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Cholesteryl Ester Transfer Protein (CETP) Inhibitor: Potential of Anacetrapib to treat Atherosclerosis and CAD

Posted in Atherogenic Processes & Pathology, Biomarkers & Medical Diagnostics, Cardiovascular Pharmacogenomics, Cell Biology, Signaling & Cell Circuits, Chemical Biology and its relations to Metabolic Disease, Chemical Genetics, FDA Regulatory Affairs, Frontiers in Cardiology and Cardiovascular Disorders, Genome Biology, Genomic Testing: Methodology for Diagnosis, Liver & Digestive Diseases Research, Medical and Population Genetics, Metabolomics, Origins of Cardiovascular Disease, Personalized and Precision Medicine & Genomic Research, Pharmacogenomics, Pharmacotherapy of Cardiovascular Disease, Population Health Management, Genetics & Pharmaceutical, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Statistical Methods for Research Evaluation, Systemic Inflammatory Response Related Disorders, tagged , , , , , , , on April 7, 2013| 15 Comments »

Curator: Aviva Lev-Ari, PhD, RN

 

UPDATED on 7/29/2018

 

HDL-C: Is It Time to Stop Calling It the ‘Good’ Cholesterol? – Medscape – Jul 27, 2018.

 

In Eli Lilly’s Pipeline: DISCONTINUING Evacetrapib, a CETP inhibitor that’s meant to boost HDL

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2015/10/12/in-eli-lillys-pipeline-discontinuing-evacetrapib-a-cetp-inhibitor-thats-meant-to-boost-hdl/

 

On April 3, 2012 we published

Fight against Atherosclerotic Cardiovascular Disease: A Biologics not a Small Molecule – Recombinant Human lecithin-cholesterol acyltransferase (rhLCAT) attracted AstraZeneca to acquire AlphaCore

ACP-501, a recombinant human lecithin-cholesterol acyltransferase (LCAT) enzyme.

LCAT, an enzyme in the bloodstream, is a key component in the reverse cholesterol transport (RCT) system, which is thought to play a major role in driving the removal of cholesterol from the body and may be critical in the management of high-density lipoprotein (HDL) cholesterol levels.  The LCAT enzyme could also play a role in a rare, hereditary disorder called familial LCAT deficiency (FLD) in which the LCAT enzyme is absent.

http://pharmaceuticalintelligence.com/2013/04/03/fight-against-atherosclerotic-cardiovascular-disease-a-biologics-not-a-small-molecule-recombinant-human-lecithin-cholesterol-acyltransferase-rhlcat-attracted-astrazeneca-to-acquire-alphacore/

On April 4, 2013, the next day, a new study was published on a novel class of compounds, cholesteryl ester transfer protein (CETP) inhibitors, has demonstrated many potentially beneficial lipid-modifying effects was published on Anacetrapib, a compound that causes near-complete CETP inhibition, has among its effects, robust reductions in LDL-C and lipoprotein(a) as well as dramatic increases in HDL-C. The ability of anacetrapib to reduce coronary disease events is being tested in the Randomized EValuation of the Effects of Anacetrapib Through Lipid-modification (REVEAL) trial (NCT01252953).

Writer’s VIEWS:

    • AstraZeneca acquisition of AlphaCore represents its market entry into the CETP inhibitor segment via an acquisition where the company did not have presence or inhouse research. The results of the second study will position Merck at a superior position upon completion of Phase III Clinical Trials for Anacetrapib
    • If Biologics will help increase HDL in wide market penetration, the market share of Statins will be negatively impacted. Patent expiration and generic market availability of Statin erode future profits
    • Anacetrapib in in Phase III clinical Trial, if successfully completed — will be the FIRST biologics to use CETP inhibition biology of lipid metabolism in the quest to fight atherosclerosis by improving CVD outcomes
    • A connection between this two events and cites in Disclosure, AstraZeneca, Merck, supporting the research of Christopher P Cannon on the study on Anacetrapib.
    • Full Article PDF file was published in Research Reports in Clinical Cardiology, one of the Journals on Beall’s list publisher, where scientists pay to have the article been published, Dove Press, on its Web site says, “There are no limits on the number or size of the papers we can publish.” See reference for Beall’s list publishers http://www.nytimes.com/2013/04/08/health/for-scientists-an-exploding-world-of-pseudo-academia.html?pagewanted=1&_r=0&emc=eta1

Study Goals:

  • testing the hypothesis that CETP inhibition may reduce atherosclerotic outcomes. 
  • answer important questions regarding the role of CETP in the biology of lipid metabolism and atherosclerosis.

Research Reports in Clinical Cardiology, 4 April 2013 Volume 2013:4 Pages 39 – 53

Dylan L Steen,1 Amit V Khera,2 Christopher P Cannon1

1TIMI Study Group, Cardiovascular Division, 2Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA

Disclosure

Dr Cannon is a member of the advisory boards of and has received grant support from Alnylam, Bristol-Myers Squibb, Pfizer, and CSL Behring; has received grant support from Accumetrics, AstraZeneca, Essentialis, GlaxoSmithKline, Merck, Regeneron, Sanofi, and Takeda; and is a clinical advisor to Automated Medical Systems. All other authors have reported that they have no relationships relevant to the contents of this paper.

Abstract: Despite major advances in cardiovascular care in recent decades, atherosclerotic cardiovascular disease remains the leading cause of morbidity and mortality worldwide. Statins have been shown to reduce cardiovascular events by 25%–40% in a dose-dependent fashion; yet additional therapies are needed to reduce vascular disease progression and acute thrombotic events. In addition to low-density lipoprotein cholesterol (LDL-C) reduction, other lipid risk factors, such as low high-density lipoprotein cholesterol (HDL-C), have created interest as therapeutic targets to lower cardiovascular risk. However, the absence of compelling data for incremental benefit of non-LDL-centric therapies in the statin era has limited their clinical use. A novel class of compounds, cholesteryl ester transfer protein (CETP) inhibitors, has demonstrated many potentially beneficial lipid-modifying effects. While in vitro and animal data for CETP inhibition have been encouraging, the initial enthusiasm for the class has been tempered by the failure of two CETP inhibitors (torcetrapib and dalcetrapib) in Phase III trials to reduce cardiovascular outcomes. Anacetrapib, a compound that causes near-complete CETP inhibition, has among its effects, robust reductions in LDL-C and lipoprotein(a) as well as dramatic increases in HDL-C. The ability of anacetrapib to reduce coronary disease events is being tested in the Randomized EValuation of the Effects of Anacetrapib Through Lipid-modification (REVEAL) trial (NCT01252953).

Keywords: anacetrapib, cholesteryl ester transfer protein, cholesteryl ester transfer protein inhibitor, atherosclerosis

  • Niacin, which augments HDL-C by 20%–25%, recently failed to lower atherosclerotic events in both the Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides and Impact on Global Health Outcomes (AIM-HIGH)6 and Treatment of HDL to Reduce the Incidence of Vascular Events (HPS2-THRIVE) trials.7,8
  • Lp(a) lowering has not yet been evaluated in randomized controlled trials, but observational and genetic (including Mendelian randomization) analyses have demonstrated an independent association of increased Lp(a) levels with increased CV events, suggesting Lp(a) lowering may confer benefit.9
  • surprising failure of the first two CETP inhibitors (torcetrapib and dalcetrapib) in Phase III outcomes trials has somewhat tempered this initial excitement and forced a re-evaluation of the complex effects of CETP inhibition on lipid metabolism and vascular biology.
  • Anacetrapib results in near-complete CETP inhibition with more pronounced lipid effects than its predecessors and is currently in a Phase III study for secondary prevention of coronary events. If successful it is likely that anacetrapib will also be considered for statin-intolerant patients and for primary prevention in patients who require LDL-C lowering beyond statin monotherapy
  • Human CETP is a 476-residue, 74 kDa, hydrophobic glycoprotein primarily secreted by the liver and adipose tissue.13 CETP was first cloned in 1987.14 The structure of CETP allows formation of a tunnel with the opening on one end interacting with HDL and the other with a very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), or LDL particle. The hydrophobic central cavity of this tunnel is large enough to allow transfer of neutral lipids (eg, cholesteryl esters [CEs], triglycerides [TGs]) from donor to acceptor particles, but conformational changes may occur to accommodate larger lipoprotein particles. The concave surface of CETP matches the curvature of the HDL particles to which it is primarily bound in the bloodstream.15,16
  • The overall effect of CETP is a net transfer of CE from HDL to these apolipoprotein B (apoB)-containing particles and TG to HDL and LDL
  • An important driver of the transfer of CE from HDL to apoB-containing particles is the production of CE from free cholesterol within HDL by lecithin acetyltransferase (LCAT).17

    The role of CETP in reverse cholesterol transport.

    Beginning in the peripheral tissues, free cholesterol is predominantly taken up by small “immature” HDL particles (eg, pre-β-HDL) via the ABCA1 transporter. Alternatively, it can be taken up by larger “mature” HDL particles (eg, HDL2) via the ABCG1 transporter. LCAT converts free cholesterol into cholesteryl ester, which is then shuttled to apoB-lipoproteins (eg, LDL, VLDL) in exchange for triglycerides. Only a minority of cholesteryl ester is delivered directly to the liver by HDL via the SR-BI; the majority is delivered indirectly to the liver by apoB-lipoproteins via the LDL recepter.

    Abbreviations: CETP, cholesteryl ester transfer protein; HDL, high-density lipoprotein; ABCA1, ATP-binding cassette transporter A1; ABCG1, ATP-binding cassette transporter G1; LCAT, lecithin acetyltransferase; apoB, apolipoprotein B; LDL, low-density lipoprotein; VLDL, very low density lipoprotein; SR-BI, scavenger receptor-BI; FC, free cholesterol; CE, cholesteryl ester.

  • One of the interesting questions in CETP deficiency is whether the HDL particles produced by potent CETP inhibition are functional. Regardless of whether reverse cholesterol transport is increased, the initial steps of cholesterol efflux from foam cells may be one of the key anti-atherogenic functions of HDL.5
  • This increased efflux is related to the very high content of LCAT and apoE in these large HDL particles, presumably driving net cholesterol efflux by promoting cholesterol esterification.36
  • effect of CETP deficiency on liver uptake of cholesteryl ester, an important downstream step in a reverse cholesterol transport. These studies suggest that there may be increased CE uptake via SR-BI as well as through a high affinity of large apoE-rich HDL for LDL receptors.20
  • meta-analysis established that three CETP genotypes were not only associated with decreased CETP activity and increased HDL but also with a lower risk of myocardial infarction (MI). For example, for each allele inherited, individuals with the TaqIB polymorphism had lower mean CETP activity (−8.6%), higher mean HDL-C (4.5%), higher mean apoA-I (2.4%), and an odds ratio for coronary disease of 0.95 (95% confidence intervals [CI], 0.92, 0.99). Similar associations were found for the other two CETP genotypes.40
  • Subsequent studies have confirmed that genetic variants leading to reduced CETP activity and its corresponding anti-atherogenic lipid profile are associated with reduced atherosclerotic outcomes.41–43
  • In ILLUSTRATE, an inverse association between HDL-C achieved and the primary endpoint of atheroma volume (r = −0.17, P , 0.001) was found. In addition, the highest quartile of HDL-C achieved (.86 mg/dL) demonstrated atheroma regression, suggesting that there may be a “threshold effect” to HDL-C elevation.68
  • Other CETP inhibitors:

Dalcetrapib
was developed by Hoffmann–La Roche until May 2012. It did not raise blood pressure and did raise HDL, but it showed no clinically meaningful efficacy.

Evacetrapib 

is under development by Eli Lilly & Company.
Torcetrapib
was developed by Pfizer until December 2006 but caused unacceptable increases in blood pressure and had net cardiovascular detriment.
Anacetrapib At the 16th International Symposium on Drugs Affecting Lipid Metabolism (New York, Oct 4-7, 2007), Merck reported on a Phase IIb study. The eight week study reported dosage correlated reduction in LDL-C and increases in HDL-C levels with no corresponding increases in blood pressure in any cohort. The increase in HDL was particularly significant, averaging 44 percent, 86 percent, 139 percent and 133 percent at doses of 10 mg, 40 mg, 150 mg and 300 mg. Merck performed a dose-ranging study of anacetrapib, with the results presented in 2009.

Anacetrapib 

Anacetrapib is a 3,5-bis-trifluoromethyl-benzene derivative with similar binding properties to CETP as torcetrapib. The compound was developed when it was found that a substitution modification of the oxazolidinone ring increased its potency for CETP inhibition in a transgenic mouse model.85 In terms of its pharmacokinetics and pharmacodynamics, anacetrapib is rapidly absorbed with a time-to-peak plasma concentration of about 4 hours. The oral bioavailability of anacetrapib is poor, with only about 20% being absorbed; however at this exposure, LDL-C is reduced up to 40% and HDL-C increased up to 140%. It is recommended that anacetrapib be taken with food (ie, low-fat diet) to increase drug exposure (and efficacy) as well as compliance.86

Anacetrapib is highly protein bound (eg, CETP) in the plasma (.99.5%). It is cleared by oxidative metabolism via Cytochrome P450 3A4 (CYP3A4) with excretion of the metabolites via the biliary/fecal route. Only a trace amount is eliminated by urinary excretion.87 Importantly, while anacetrapib is a sensitive CYP3A4 substrate, anacetrapib neither inhibits nor induces CYP3A4 activity. No meaningful interactions have been found between anacetrapib and simvastatin, digoxin, or warfarin.86 Anacetrapib in part to its redistribution to adipose tissue has a long terminal half-life.88

In terms of safety endpoints, anacetrapib demonstrated no increase in side effects (including myalgia), drug-related adverse effects, adverse events leading to drug discontinuation, or other important safety endpoints, such as BP, electrolyte, aldosterone, creatinine kinase, or transaminase levels. A very small increase in C-reactive protein of undetermined significance was seen with anacetrapib, which notably was also reported with torcetrapib and dalcetrapib in their Phase III studies. It is unknown whether this is a class effect as the small sample size in the evacetrapib Phase II study limits evaluation of small C-reactive protein changes.

It is expected that the REVEAL (the Phase III) population will also have lower starting LDL-C levels, both because statin-intolerant subjects will not be enrolled and because of more stringent lipid entry criteria. The final major difference is that the primary endpoint in REVEAL is focused on coronary events, while ACCELERATE has a broader primary endpoint. A broader primary endpoint along with a slightly higher risk population will allow for a shorter follow-up duration and much smaller sample size in ACCELERATE.

Conclusion

  • CETP remains a valid target and that the lipid changes resulting from its inhibition may be protective. The biology of CETP inhibition is complex, and questions remain regarding which lipid changes (eg, reductions in LDL and Lp(a), increases in HDL) are most likely to be important and whether there are still unknown effects that may negate any overall clinical benefit.
  • if potent CETP inhibition is found to be beneficial, it is still unclear whether this effect will be homogeneous or vary based on individual metabolism.
  • anacetrapib-induced HDL (especially the apoE-rich HDL2 particles) may have an enhanced ability for reverse cholesterol transport without any known adverse effects. Importantly, if a threshold effect for HDL-C augmentation exists, the vast majority of patients taking anacetrapib would be expected to cross it.
  • Despite a difficult beginning for the class of CETP inhibitors, anacetrapib and evacetrapib hold promise as future therapies for patients with atherosclerosis
REFERENCES

1. Cholesterol Treatment Trialists’ (CTT) Collaboration, Baigent C, Blackwell L, et al. Efficacy and safety of more intensive lowering of LDL cholesterol: A meta-analysis of data from 170,000 participants in 26 randomised trials. Lancet. 2010;376(9753):1670–1681.

2. Cannon CP, Braunwald E, McCabe CH, et al. Intensive versus moderate lipid lowering with statins after acute coronary syndromes. N Engl J Med. 2004;350(15):1495–1504.

3. Steinberg D. The rationale for initiating treatment of hypercholesterolemia in young adulthood. Curr Atheroscler Rep. 2013;15(1):296.

4. Gordon T, Castelli WP, Hjortland MC, Kannel WB, Dawber TR. High density lipoprotein as a protective factor against coronary heart disease. the framingham study. Am J Med. 1977;62(5):707–714.

5. Vergeer M, Holleboom AG, Kastelein JJ, Kuivenhoven JA. The HDL hypothesis: Does high-density lipoprotein protect from atherosclerosis? J Lipid Res. 2010;51(8):2058–2073.

6. AIM-HIGH Investigators, Boden WE, Probstfield JL, et al. Niacin in patients with low HDL cholesterol levels receiving intensive statin therapy. N Engl J Med. 2011;365(24):2255–2267

7. Armitage J, Baigent C, Chen Z, Landray M. Treatment of HDL to reduce the incidence of vascular events HPS2-THRIVE. Available from: http://clinicaltrials.gov/ct2/show/NCT00461630. Updated 2010. Accessed February 1, 2012.

8. Merck announces HPS2-THRIVE study of TREDAPTIVE (extended-release Niacin/Laropriprant) did not achieve primary endpoint. Available from: http://www.mercknewsroom.com/press-release/prescription-medicine-news/merck-announces-hps2-thrive-study-tredaptive-extended-relea. Updated 2012. Accessed December 31, 2012.

9. Tsimikas S, Hall JL. Lipoprotein(a) as a potential causal genetic risk factor of cardiovascular disease: A rationale for increased efforts to understand its pathophysiology and develop targeted therapies. J Am Coll Cardiol. 2012;60(8):716–721.

10. Brown ML, Inazu A, Hesler CB, et al. Molecular basis of lipid transfer protein deficiency in a family with increased high-density lipoproteins. Nature. 1989;342(6248):448–451.

11. Inazu A, Brown ML, Hesler CB, et al. Increased high-density lipoprotein levels caused by a common cholesteryl-ester transfer protein gene mutation. N Engl J Med. 1990;323(18):1234–1238.

12. Ohtani R, Inazu A, Noji Y, et al. Novel mutations of cholesteryl ester transfer protein (CETP) gene in Japanese hyperalphalipoproteinemic subjects. Clin Chim Acta. 2012;413(5–6):537–543.

13. Chapman MJ, Le Goff W, Guerin M, Kontush A. Cholesteryl ester transfer protein: At the heart of the action of lipid-modulating therapy with statins, fibrates, niacin, and cholesteryl ester transfer protein inhibitors. Eur Heart J. 2010;31(2):149–164.

14. Drayna D, Jarnagin AS, McLean J, et al. Cloning and sequencing of human cholesteryl ester transfer protein cDNA. Nature. 1987;327(6123): 632–634.

15. Qiu X, Mistry A, Ammirati MJ, et al. Crystal structure of cholesteryl ester transfer protein reveals a long tunnel and four bound lipid molecules. Nat Struct Mol Biol. 2007;14(2):106–113.

16. Zhang L, Yan F, Zhang S, et al. Structural basis of transfer between lipoproteins by cholesteryl ester transfer protein. Nat Chem Biol. 2012;8(4):342–349.

17. Barter PJ, Brewer HB Jr, Chapman MJ, Hennekens CH, Rader DJ, Tall AR. Cholesteryl ester transfer protein: A novel target for raising HDL and inhibiting atherosclerosis. Arterioscler Thromb Vasc Biol. 2003;23(2):160–167.

18. Niesor EJ. Different effects of compounds decreasing cholesteryl ester transfer protein activity on lipoprotein metabolism. Curr Opin Lipidol. 2011;22(4):288–295.

19. Arai T, Tsukada T, Murase T, Matsumoto K. Particle size analysis of high density lipoproteins in patients with genetic cholesteryl ester transfer protein deficiency. Clin Chim Acta. 2000;301(1–2):103–117.

20. Yamashita S, Sprecher DL, Sakai N, Matsuzawa Y, Tarui S, Hui DY. Accumulation of apolipoprotein E-rich high density lipoproteins in hyperalphalipoproteinemic human subjects with plasma cholesteryl ester transfer protein deficiency. J Clin Invest. 1990;86(3):688–695.

21. Ikewaki K, Nishiwaki M, Sakamoto T, et al. Increased catabolic rate of low density lipoproteins in humans with cholesteryl ester transfer protein deficiency. J Clin Invest. 1995;96(3):1573–1581.

22. Millar JS, Brousseau ME, Diffenderfer MR, et al. Effects of the cholesteryl ester transfer protein inhibitor torcetrapib on apolipo­protein B100 metabolism in humans. Arterioscler Thromb Vasc Biol. 2006;26(6):1350–1356.

23. Rosenson RS, Brewer HB Jr, Davidson WS, et al. Cholesterol efflux and atheroprotection: Advancing the concept of reverse cholesterol transport. Circulation. 2012;125(15):1905–1919.

24. Foger B, Chase M, Amar MJ, et al. Cholesteryl ester transfer protein corrects dysfunctional high density lipoproteins and reduces aortic atherosclerosis in lecithin cholesterol acyltransferase transgenic mice. J Biol Chem. 1999;274(52):36912–36920.

25. Hayek T, Masucci–Magoulas L, Jiang X, et al. Decreased early athero­sclerotic lesions in hypertriglyceridemic mice expressing cholesteryl ester transfer protein transgene. J Clin Invest. 1995;96(4):2071–2074.

26. MacLean PS, Bower JF, Vadlamudi S, et al. Cholesteryl ester transfer protein expression prevents diet-induced atherosclerotic lesions in male db/db mice. Arterioscler Thromb Vasc Biol. 2003;23(8):1412–1415.

27. Marotti KR, Castle CK, Boyle TP, Lin AH, Murray RW, Melchior GW. Severe atherosclerosis in transgenic mice expressing simian cholesteryl ester transfer protein. Nature. 1993;364(6432):73–75.

28. Plump AS, Masucci–Magoulas L, Bruce C, Bisgaier CL, Breslow JL, Tall AR. Increased atherosclerosis in ApoE and LDL receptor gene knock-out mice as a result of human cholesteryl ester transfer protein transgene expression. Arterioscler Thromb Vasc Biol. 1999;19(4):1105–1110.

29. Westerterp M, van der Hoogt CC, de Haan W, et al. Cholesteryl ester transfer protein decreases high-density lipoprotein and severely aggra­vates atherosclerosis in APOE*3-leiden mice. Arterioscler Thromb Vasc Biol. 2006;26(11):2552–2559.

30. Tanigawa H, Billheimer JT, Tohyama J, Zhang Y, Rothblat G, Rader DJ. Expression of cholesteryl ester transfer protein in mice promotes macrophage reverse cholesterol transport. Circulation. 2007;116(11): 1267–1273.

31. Schwartz CC, VandenBroek JM, Cooper PS. Lipoprotein cholesteryl ester production, transfer, and output in vivo in humans. J Lipid Res. 2004;45(9):1594–1607.

32. Khera AV, Wolfe ML, Cannon CP, Qin J, Rader DJ. On-statin choles­teryl ester transfer protein mass and risk of recurrent coronary events (from the pravastatin or atorvastatin evaluation and infection therapy-thrombolysis in myocardial infarction 22 [PROVE IT-TIMI 22] study). Am J Cardiol. 2010;106(4):451–456.

33. Evans GF, Bensch WR, Apelgren LD, et al. Inhibition of cholesteryl ester transfer protein in normocholesterolemic and hypercholester­olemic hamsters: Effects on HDL subspecies, quantity, and apolipo­protein distribution. J Lipid Res. 1994;35(9):1634–1645.

34. Rittershaus CW, Miller DP, Thomas LJ, et al. Vaccine-induced antibodies inhibit CETP activity in vivo and reduce aortic lesions in a rabbit model of atherosclerosis. Arterioscler Thromb Vasc Biol. 2000;20(9):2106–2112.

35. Sugano M, Makino N, Sawada S, et al. Effect of antisense oligonucle­otides against cholesteryl ester transfer protein on the development of atherosclerosis in cholesterol-fed rabbits. J Biol Chem. 1998;273(9): 5033–5036.

36. Matsuura F, Wang N, Chen W, Jiang XC, Tall AR. HDL from CETP-deficient subjects shows enhanced ability to promote cholesterol efflux from macrophages in an apoE- and ABCG1-dependent pathway. J Clin Invest. 2006;116(5):1435–1442.

37. Curb JD, Abbott RD, Rodriguez BL, et al. A prospective study of HDL-C and cholesteryl ester transfer protein gene mutations and the risk of coro­nary heart disease in the elderly. J Lipid Res. 2004;45(5): 948–953.

38. Moriyama Y, Okamura T, Inazu A, et al. A low prevalence of coronary heart disease among subjects with increased high-density lipoprotein cholesterol levels, including those with plasma cholesteryl ester transfer protein deficiency. Prev Med. 1998;27(5 Pt 1): 659–667.

39. Zhong S, Sharp DS, Grove JS, et al. Increased coronary heart disease in Japanese–American men with mutation in the cholesteryl ester transfer protein gene despite increased HDL levels. J Clin Invest. 1996;97(12): 2917–2923.

40. Thompson A, Di Angelantonio E, Sarwar N, et al. Association of cholesteryl ester transfer protein genotypes with CETP mass and activ­ity, lipid levels, and coronary risk. JAMA. 2008;299(23):2777–2788.

41. Ridker PM, Pare G, Parker AN, Zee RY, Miletich JP, Chasman DI. Polymorphism in the CETP gene region, HDL cholesterol, and risk of future myocardial infarction: Genomewide analysis among 18 245 initially healthy women from the women’s genome health study. Circ Cardiovasc Genet. 2009;2(1):26–33.

42. Voight BF, Peloso GM, Orho–Melander M, et al. Plasma HDL cho­lesterol and risk of myocardial infarction: A mendelian randomisation study. Lancet. 2012;380(9841):572–580.

43. Johannsen TH, Frikke–Schmidt R, Schou J, Nordestgaard BG, Tybjaerg–Hansen A. Genetic inhibition of CETP, ischemic vascular disease and mortality, and possible adverse effects. J Am Coll Cardiol. 2012;60(20):2041–2048.

submit your manuscript | http://www.dovepress.com Dovepress Dovepress 51 Anacetrapib for coronary heart disease Research Reports in Clinical Cardiology 2013:4

44. Clark RW, Ruggeri RB, Cunningham D, Bamberger MJ. Descrip­tion of the torcetrapib series of cholesteryl ester transfer pro­tein inhibitors, including mechanism of action. J Lipid Res. 2006;47(3):537–552.

45. Ranalletta M, Bierilo KK, Chen Y, et al. Biochemical characterization of cholesteryl ester transfer protein inhibitors. J Lipid Res. 2010;51(9): 2739–2752.

46. Brousseau ME, Schaefer EJ, Wolfe ML, et al. Effects of an inhibitor of cholesteryl ester transfer protein on HDL cholesterol. N Engl J Med. 2004;350(15):1505–1515.

47. Clark RW, Sutfin TA, Ruggeri RB, et al. Raising high-density lipoprotein in humans through inhibition of cholesteryl ester transfer protein: An initial multidose study of torcetrapib. Arterioscler Thromb Vasc Biol. 2004;24(3):490–497.

48. McKenney JM, Davidson MH, Shear CL, Revkin JH. Efficacy and safety of torcetrapib, a novel cholesteryl ester transfer protein inhibitor, in individuals with below-average high-density lipoprotein cholesterol levels on a background of atorvastatin. J Am Coll Cardiol. 2006;48(9): 1782–1790.

49. Morehouse LA, Sugarman ED, Bourassa PA, et al. Inhibition of CETP activity by torcetrapib reduces susceptibility to diet-induced atherosclero­sis in New Zealand White rabbits. J Lipid Res. 2007;48(6): 1263–1272.

50. Barter PJ, Caulfield M, Eriksson M, et al. Effects of torcetrapib in patients at high risk for coronary events. N Engl J Med. 2007;357(21): 2109–2122.

51. Kastelein JJ, van Leuven SI, Burgess L, et al. Effect of torcetrapib on carotid atherosclerosis in familial hypercholesterolemia. N Engl J Med. 2007;356(16):1620–1630.

52. Bots ML, Visseren FL, Evans GW, et al. Torcetrapib and carotid intima-media thickness in mixed dyslipidaemia (RADI­ANCE 2 study): A randomised, double-blind trial. Lancet. 2007;370(9582):153–160.

53. Nissen SE, Tardif JC, Nicholls SJ, et al. Effect of torcetrapib on the progression of coronary atherosclerosis. N Engl J Med. 2007;356(13): 1304–1316.

54. Hu X, Dietz JD, Xia C, et al. Torcetrapib induces aldosterone and cor­tisol production by an intracellular calcium-mediated mechanism inde­pendently of cholesteryl ester transfer protein inhibition. Endocrinology. 2009;150(5):2211–2219.

55. Forrest MJ, Bloomfield D, Briscoe RJ, et al. Torcetrapib-induced blood pressure elevation is independent of CETP inhibition and is accompa­nied by increased circulating levels of aldosterone. Br J Pharmacol. 2008;154(7):1465–1473.

56. DePasquale M, Cadelina G, Knight D, et al. Mechanistic studies of blood pressure in rats treated with a series of cholesteryl ester transfer protein inhibitors. Drug Develop Res. 2009;70(10.1002/ddr.20282):35.

57. Clerc RG, Stauffer A, Weibel F, et al. Mechanisms underlying off-target effects of the cholesteryl ester transfer protein inhibitor torcetrapib involve L-type calcium channels. J Hypertens. 2010;28(8): 1676–1686.

58. Sofat R, Hingorani AD, Smeeth L, et al. Separating the mechanism-based and off-target actions of cholesteryl ester transfer protein inhibitors with CETP gene polymorphisms. Circulation. 2010;121(1): 52–62.

59. Blasi E, Bamberger M, Knight D, et al. Effects of CP-532,623 and torcetrapib, cholesteryl ester transfer protein inhibitors, on arterial blood pressure. J Cardiovasc Pharmacol. 2009;53(6):507–516.

60. Connelly MA, Parry TJ, Giardino EC, et al. Torcetrapib produces endothelial dysfunction independent of cholesteryl ester transfer protein inhibition. J Cardiovasc Pharmacol. 2010;55(5):459–468.

61. Simic B, Hermann M, Shaw SG, et al. Torcetrapib impairs endothelial function in hypertension. Eur Heart J. 2012;33(13):1615–1624.

62. Westerterp M, Koetsveld J, Tall AR. Cholesteryl ester transfer protein inhibition: A dysfunctional endothelium. J Cardiovasc Pharmacol. 2010;55(5):456–458.

63. Guerin M, Le Goff W, Duchene E, et al. Inhibition of CETP by torce­trapib attenuates the atherogenicity of postprandial TG-rich lipoproteins in type IIB hyperlipidemia. Arterioscler Thromb Vasc Biol. 2008;28(1): 148–154.

64. Yvan–Charvet L, Matsuura F, Wang N, et al. Inhibition of cholesteryl ester transfer protein by torcetrapib modestly increases macrophage cholesterol efflux to HDL. Arterioscler Thromb Vasc Biol. 2007;27(5): 1132–1138.

65. Tall AR. The effects of cholesterol ester transfer protein inhibition on cholesterol efflux. Am J Cardiol. 2009;104(Suppl 10):39E–45E.

66. Tchoua U, D’Souza W, Mukhamedova N, et al. The effect of cholesteryl ester transfer protein overexpression and inhibition on reverse choles­terol transport. Cardiovasc Res. 2008;77(4):732–739.

67. Briand F, Thieblemont Q, Andre A, Ouguerram K, Sulpice T. CETP inhibitor torcetrapib promotes reverse cholesterol transport in obese insulin-resistant CETP-ApoB100 transgenic mice. Clin Transl Sci. 2011;4(6):414–420.

68. Nicholls SJ, Tuzcu EM, Brennan DM, Tardif JC, Nissen SE. Cholesteryl ester transfer protein inhibition, high-density lipoprotein raising, and progression of coronary atherosclerosis: Insights from ILLUSTRATE (investigation of lipid level management using coronary ultrasound to assess reduction of atherosclerosis by CETP inhibition and HDL elevation). Circulation. 2008;118(24):2506–2514.

69. Fryirs MA, Barter PJ, Appavoo M, et al. Effects of high-density lipoproteins on pancreatic beta-cell insulin secretion. Arterioscler Thromb Vasc Biol. 2010;30(8):1642–1648.

70. Barter PJ, Rye KA, Tardif JC, et al. Effect of torcetrapib on glucose, insulin, and hemoglobin A1c in subjects in the investigation of lipid level management to understand its impact in atherosclerotic events (ILLUMINATE) trial. Circulation. 2011;124(5):555–562.

71. Funder JW. Aldosterone, hypertension and heart failure: Insights from clinical trials. Hypertens Res. 2010;33(9):872–875.

72. Kuivenhoven JA, de Grooth GJ, Kawamura H, et al. Effectiveness of inhibition of cholesteryl ester transfer protein by JTT-705 in combina­tion with pravastatin in type II dyslipidemia. Am J Cardiol. 2005;95(9): 1085–1088.

73. Okamoto H, Yonemori F, Wakitani K, Minowa T, Maeda K, Shinkai H. A cholesteryl ester transfer protein inhibitor attenuates atherosclerosis in rabbits. Nature. 2000;406(6792):203–207.

74. de Grooth GJ, Kuivenhoven JA, Stalenhoef AF, et al. Efficacy and safety of a novel cholesteryl ester transfer protein inhibitor, JTT-705, in humans: A randomized phase II dose-response study. Circulation. 2002;105(18):2159–2165.

75. Niesor EJ, Magg C, Ogawa N, et al. Modulating cholesteryl ester transfer protein activity maintains efficient pre-beta-HDL formation and increases reverse cholesterol transport. J Lipid Res. 2010;51(12): 3443–3454.

76. Derks M, Anzures–Cabrera J, Turnbull L, Phelan M. Safety, tolerability and pharmacokinetics of dalcetrapib following single and multiple ascending doses in healthy subjects: A randomized, double-blind, placebo-controlled, phase I study. Clin Drug Investig. 2011;31(5):325–335.

77. Stein EA, Roth EM, Rhyne JM, Burgess T, Kallend D, Robinson JG. Safety and tolerability of dalcetrapib (RO4607381/JTT-705): Results from a 48-week trial. Eur Heart J. 2010;31(4):480–488.

78. Fayad ZA, Mani V, Woodward M, et al. Safety and efficacy of dalce­trapib on atherosclerotic disease using novel non-invasive multimo­dality imaging (dal-PLAQUE): A randomised clinical trial. Lancet. 2011;378(9802):1547–1559.

79. Luscher TF. Effects of dalcetrapib on vascular function: Results of phase IIb dal-VESSEL study. Available from: http://www.escardio.org/about/press/press-releases/esc11-paris/Pages/HL1-dal-VESSEL.aspx. Updated 2011. Accessed February 1, 2012.

80. Schwartz GG, Olsson AG, Ballantyne CM, et al. Rationale and design of the dal-OUTCOMES trial: Efficacy and safety of dalcetrapib in patients with recent acute coronary syndrome. Am Heart J. 2009;158(6):896–901. e3.

81. Miller R. Roche stops dalcetrapib trial for lack of benefit. Available from: http://www.theheart.org/article/1395141.do. Updated 2012. Accessed June 21, 2012.

82. Schwartz GG, Olsson AG, Abt M, et al. Effects of dalcetrapib in patients with a recent acute coronary syndrome. N Engl J Med. 2012;367(22):2089–2099.

83. Nicholls SJ, Brewer HB, Kastelein JJ et al. Effects of the CETP Inhibitor evacetrapib administered as monotherpay or in combination with statins on HDL and LDL cholesterol: a randomized controlled trial. JAMA. 2011;306(19):2099-2109.

84. Eli Lilly and Company. A study of evacetrapib in high-risk vascular disease (ACCELERATE); NCT01687998. Available from: http://www.clinicaltrials.gov/ct2/show/study/NCT01687998?term=evacetrapib&rank=3. Updated 2012. Accessed November 17, 2012.

85. Smith CJ, Ali A, Hammond ML, et al. Biphenyl-substituted oxazolidinones as cholesteryl ester transfer protein inhibitors: Modifica­tions of the oxazolidinone ring leading to the discovery of anacetrapib. J Med Chem. 2011;54(13):4880–4895.

86. Gutstein DE, Krishna R, Johns D, et al. Anacetrapib, a novel CETP inhibitor: Pursuing a new approach to cardiovascular risk reduction. Clin Pharmacol Ther. 2012;91(1):109–122.

87. Kumar S, Tan EY, Hartmann G, et al. Metabolism and excretion of anacetrapib, a novel inhibitor of the cholesteryl ester transfer protein, in humans. Drug Metab Dispos. 2010;38(3):474–483.

88. Dansky HM, Bloomfield D, Gibbons P, et al. Efficacy and safety after cessation of treatment with the cholesteryl ester transfer protein inhibitor anacetrapib (MK-0859) in patients with primary hypercholesterolemia or mixed hyperlipidemia. Am Heart J. 2011;162(4): 708–716.

89. Bloomfield D, Carlson GL, Sapre A, et al. Efficacy and safety of the cholesteryl ester transfer protein inhibitor anacetrapib as monotherapy and coadministered with atorvastatin in dyslipidemic patients. Am Heart J. 2009;157(2):352–360. e2.

90. Krishna R, Anderson MS, Bergman AJ, et al. Effect of the cholesteryl ester transfer protein inhibitor, anacetrapib, on lipoproteins in patients with dyslipidaemia and on 24-h ambulatory blood pressure in healthy individuals: Two double-blind, randomised placebo-controlled phase I studies. Lancet. 2007;370(9603):1907–1914.

91. Krauss RM, Wojnooski K, Orr J, et al. Changes in lipoprotein subfrac­tion concentration and composition in healthy individuals treated with the CETP inhibitor anacetrapib. J Lipid Res. 2012;53(3): 540–547.

92. Krishna R, Bergman AJ, Green M, Dockendorf MF, Wagner JA, Dykstra K. Model-based development of anacetrapib, a novel cholesteryl ester transfer protein inhibitor. AAPS J. 2011;13(2): 179–190.

93. Yvan–Charvet L, Kling J, Pagler T, et al. Cholesterol efflux potential and antiinflammatory properties of high-density lipoprotein after treatment with niacin or anacetrapib. Arterioscler Thromb Vasc Biol. 2010;30(7):1430–1438.

94. Castro–Perez J, Briand F, Gagen K, et al. Anacetrapib promotes reverse cholesterol transport and bulk cholesterol excretion in Syrian golden hamsters. J Lipid Res. 2011;52(11):1965–1973.

95. Cannon CP, Dansky HM, Davidson M, et al. Design of the DEFINE trial: Determining the EFficacy and tolerability of CETP INhibition with AnacEtrapib. Am Heart J. 2009;158(4):513–519. e3.

96. Cannon CP, Shah S, Dansky HM, et al. Safety of anacetrapib in patients with or at high risk for coronary heart disease. N Engl J Med. 2010;363(25):2406–2415.

97. Davidson M, Liu SX, Barter P, et al. Measurement of LDL-C after treatment with the CETP inhibitor anacetrapib. J Lipid Res. 2013;54(2):467–472.

98. Brinton E, Liu S, Stepanavage M, et al. Lipid-modifying effects of anacetrapib in patients with lower versus higher baseline levels of HDL-C, LDL-C, and TG: Pre-specified subgroup analyses of the DEFINE (determining the efficacy and tolerability of CETP INhibition with AnacEtrapib) trial. Circulation. 2011;124:A9649.

99. Gotto A, Cannon C, Shah S, et al. Lipid modifying effects of anacetrapib: Pre-specified subgroup analyses. Circulation. 2011;124: A15035.

100. Bowman L. REVEAL: Randomized EValuation of the effects of anacetrapib through lipid-modification. Available from: http://www.clinicaltrials.gov/ct2/show/NCT01252953?term=anacetrapib&rank=4. Updated 2011. Accessed June 25, 2012.

101. Cannon CP. High-density lipoprotein cholesterol as the Holy Grail. JAMA. 2011;306(19):2153–2155 Research Reports in Clinical Cardiology 2013:4

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Amyloidosis with Cardiomyopathy

Posted in Biomarkers & Medical Diagnostics, Cardiovascular Pharmacogenomics, Cerebrovascular and Neurodegenerative Diseases, Chemical Biology and its relations to Metabolic Disease, Chemical Genetics, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Frontiers in Cardiology and Cardiovascular Disorders, Genome Biology, Genomic Testing: Methodology for Diagnosis, Human Immune System in Health and in Disease, International Global Work in Pharmaceutical, Liver & Digestive Diseases Research, Medical and Population Genetics, Medical Imaging Technology, Image Processing/Computing, MRI, CT, Nuclear Medicine, Ultra Sound, Molecular Genetics & Pharmaceutical, Personalized and Precision Medicine & Genomic Research, Pharmaceutical Industry Competitive Intelligence, Pharmacotherapy and Cell Activity, Pharmacotherapy of Cardiovascular Disease, Proteomics, Systemic Inflammatory Response Related Disorders, tagged , , , , , , , , , on March 31, 2013| 11 Comments »

Amyloidosis with Cardiomyopathy

Author: Larry H Bernstein, MD, FACP
Introduction
Amyloidosis describes the various clinical syndromes that occur as a result of damage by amyloid deposits in tissues and organs throughout the body.  Systemic amyloidosis is a relatively rare multisystem disease caused by the deposition of misfolded protein in various tissues and organs. The term amyloid describes the deposition in the extracellular space of certain proteins in a highly characteristic, insoluble fibrillar form.  The disease entity is a disorder of misfolded or misassembled proteins.  There is extracellular amyloid fiber laid down as cross β-sheets disrupting organ function, which may affect the pancreas, kidney, autonomic nervous system, the heart, and in one form causes carpal tunnel syndrome.
It may present to almost any specialty, and diagnosis is frequently delayed. Cardiac involvement is a leading cause of morbidity and mortality, especially in primary light chain (AL) amyloidosis and in both wild-type and hereditary transthyretin amyloidosis. The heart is also occasionally involved in acquired serum amyloid A type (AA) amyloidosis and other rare hereditary types. Clinical phenotype varies greatly between different types of amyloidosis, and even the cardiac presentation has a great spectrum. The incidence of amyloidosis is uncertain, but it is thought that the most frequently diagnosed AL amyloidosis has an annual incidence of 6 to 10 cases per million population in the United Kingdom and United States.
The molecular basis for this particular phenomenon came with the extensive work done on multiple myeloma, antibody structure, and light chains.  In 1950, the discovery of a familial amyloid polyneuropathy was described in Portugal, and there were similar diseases in Sweden and Japan.  There were 72 known variants of transthyretin (TTR) in 1995, and now there are 100.  In addition, the occurance of different TTR associated variants with and without (amyloid) is found is Brazil, UK, US, Israel, Spain, France, Germany, Denmark, and Africa.  The table of variants, organ damage, and geographic location is too large to place on this document. If we refer to amyloid cardiomyopathy, it is exclusively a primary amyloidopathy, not secondary to light chain disorders or an inflammatory disease.  If we consider amyloidosis, we also have to consider family history, organ dysfunction, and we have to make a distinction between primary cardiac involvement, autonomic nervous system instability, and the two coexisting.  Familial amyloid polyneuropathy (FAP) is an extremely debilitating and progressive disease that is only treatable by liver transplantation.  Primary amyloid cardiomyopathy has been treated by heart transplant.  The qualifying statement here is, it depends.

Primary and Secondary Amyloidoses

Amyloid was originally described by pathologists based on microscopy. Amyloidoses are a systemic primary or secondary disease. There are distinctions to be made based on location and type.  The clinical significance of amyloid disease varies enormously, ranging from incidental asymptomatic deposits to localized disease through to rapidly fatal systemic forms that can affect multiple vital organs.
Common causes of secondary amyloidosis are – light chain production (AL) as in plasma cell dyscrasia, amyloid A (AA), senile systemic amyloidosis (diagnosed rarely in life).  The systemic amyloidoses are designated by a capital A (for amyloid) followed by the abbreviation for the chemical identity of the fibril protein. Thus, TTR amyloidosis is abbreviated ATTR, and immunoglobulin light chain type amyloidosis is abbreviated AL. Both normal-sequence TTR and variant-sequence TTR form amyloidosis. Normal-sequence TTR forms cardiac amyloidosis in elderly people, termed senile cardiac amyloidosis (SCA). When it was recognized that SCA is often accompanied by microscopic deposits in many other organs, the alternative name senile systemic amyloidosis (SSA) was proposed. Both terms are now used.
Currently available therapy is focused on reducing the supply of the respective amyloid fibril precursor protein and supportive medical care, which together have greatly improved survival. Chemotherapy and anti-inflammatory treatment for the disorders that underlie AL and AA amyloidosis are guided by serial measurements of the respective circulating amyloid precursor proteins, i.e. serial serum free light chains in AL and serum amyloid A protein in AA type.
Quality of life and prognosis of some forms of hereditary systemic amyloidosis can be improved by liver and other organ transplants. Various new therapies, ranging from silencing RNA, protein stabilizers to monoclonal antibodies, aimed at inhibiting fibril precursor supply, fibril formation or the persistence of amyloid deposits, are in development; some are already in clinical phase.
Ann Clin Biochem May 2012; 49(3 ): 229-241   http://acb.2011.011225v1 49/3/229

What is transthyretin (TTR)?

TTR is a  tetramer of 4 127 amino acid subunits synthesized by the liver that circulates as a transporter of thyroxin, and with retinol-binding protein, transports vitamin A.  It was originally defined by the migration in electrophoresis more anodal to albumin, hence, prealbumin.  It is present in cerebrospinal fluid, secreted by the choroid plexus.  The TTR monomer contains 8 antiparallel beta pleated sheet domains. TTR can be found in plasma and in cerebrospinal fluid and is synthesized by the choroid plexus of the brain and, to a lesser degree, by the retina. Its gene is located on the long arm of chromosome 18 and contains 4 exons and 3 introns.
The concentration in serum can be expected to be above 20 mg/dL in a health adult, but the protein decreases by 1 mg/dL/day postoperatively, and it decreases with acute or chronic renal failure, pneumonia or sepsis, rising again with the onset of anabolism.  Patients in the pulmonary intensive care unit have TTR levels that remain low for 7-10 days, but followup data for the remainder of the hospital stay or in relationship to readmission in the six months after release from hospital care was not part of the study.
A decrease in TTR is associated with the systemic inflammatory response, whereby, the liver reprioritizes the synthesis of proteins with an increase in acute phase reactants (APRs), namely, C-reactive protein (CRP) and a-1 acid glycoprotein, and decreased albumin and TTR.  The inflammatory condition maintains a euthyroid status with decreased TTR because of the availability of free thyroxine in equilibrium with the lower binding protein.  This has been referred to sick euthyroid status. The role in thyroxine transport is not insignificant, as chronic protein malnutrition is associated with hypothyroidism, as originally described by Prof. Yves Ingenbleek, Univ. Louis Pateur, Starsbourg, Fr. in Senegalese children with Kwashiorkor.  However, the importance of TTR as a unique biomarker is not to be downgraded because of what is often refered to as “an inverted APR”.
Transthyretin was discovered to be a good reflection of the “lean body mass”, by Vernon Young, MIT, and Ingenbleek, as a result of 3 decades of study. The ratio of S:N being 1:20 in plant proteins and 1:12.5 in animal sources, is closely related to methylation reactions and sustained deficiency of S intake results in elevated homocysteine level.

What is FAP?

Familial amyloid polyneuropathy (FAP), also called transthyretin-related hereditary amyloidosis, transthyretin amyloidosis or Corino de Andrade’s disease, is an autosomal dominant neurodegenerative disease. It is a form of amyloidosis, and was first identified and described by Portuguese neurologist Mário Corino da Costa Andrade, in the 1950s.FAP is distinct from senile systemic amyloidosis (SAS), which is not inherited, and which was determined to be the primary cause of death for 70% of supercentenarians who have been autopsied.
Familial amyloid polyneuropathy (FAP) is an extremely debilitating and progressive disease that is only treatable by liver transplantation.  Primary amyloid cardiomyopathy has been treated by heart transplant.  The qualifying statement here is, it depends.  Those patients with TTR-amyloidopathy have a specific gene substitution in the TTR gene. Consequently, there is circulation TTR, but it is not effectively involved in thyroxine transport.

Characteristics.

Usually manifesting itself between 20 and 40 years of age, it is characterized by pain, paresthesia, muscular weakness and autonomic dysfunction. In its terminal state, the kidneys and the heart are affected. FAP is characterized by the systemic deposition of amyloidogenic variants of the transthyretin protein, especially in the peripheral nervous system, causing a progressive sensory and motor polyneuropathy. The age at symptom onset, pattern of organ involvement, and disease course vary, but most mutations are associated with cardiac and/or nerve involvement. The gastrointestinal tract, vitreous, lungs, and carpal ligament are also frequently affected. When the peripheral nerves are prominently affected, the disease is termed familial amyloidotic polyneuropathy (FAP). When the heart is involved heavily but the nerves are not, the disease is called familial amyloid cardiomyopathy (FAC). Regardless of which organ is primarily targeted, the general term is simply amyloidosis-transthyretin type, abbreviated ATTR.

Genetics.

  1. TTR mutations accelerate the process of TTR amyloid formation and are the most important risk factor for the development of clinically significant ATTR. More than 85 amyloidogenic TTR variants cause systemic familial amyloidosis. The variant TTR is mostly produced by the liver. Amyloidogenic TTR mutations destabilize TTR monomers or tetramers, allowing the molecule to more easily attain an amyloidogenic intermediate conformation. The tetramer has to dissociate into misfolded monomers to aggregate into a variety of structures including amyloid fibrils. Because most patients are heterozygotes, they deposit both mutant and wild type TTR subnits.
  2. Familial amyloid polyneuropathy has an autosomal dominant pattern of inheritance. FAP is caused by a mutation of the TTR gene, located on human chromosome 18q12.1-11.2. A replacement of valine by methionine at position 30 (TTR V30M) is the mutation most commonly found in FAP.
  3. The disease in the TTR V30M kindreds was termed FAP because early symptoms arose from peripheral neuropathy, but these patients actually have systemic amyloidosis, with widespread deposits often involving the heart, gastrointestinal tract, eye, and other organs.
  4. TTR V122I: This variant, carried by 3.9% of African Americans and over 5% of the population in some areas of West Africa, increases the risk of late-onset (after age 60 years) cardiac amyloidosis. It appears to be the most common amyloid-associated TTR variant worldwide. Affected patients usually do not have peripheral neuropathy.
  5. TTR T60A: This variant causes late-onset systemic amyloidosis with cardiac, and sometimes neuropathic, involvement. This variant originated in northwest Ireland and is found in Irish and Irish American patients.
  6. TTR L58H: Typically affecting the carpal ligament and nerves of the upper extremities, this variant originated in Germany. It has spread throughout the United States but is most common in the mid-Atlantic region.
  7. TTR G6S: This is the most common TTR variant, but it appears to be a neutral polymorphism not associated with amyloidosis. It is carried by about 10% of people of white European descent.

Cardiac transthyretin (TTR) amyloidosis

Cardiac amyloidosis of transthyretin fibril protein (ATTR) type is an infiltrative cardiomyopathy characterised by ventricular wall thickening and diastolic heart failure. More than 27 different precursor proteins have the propensity to form amyloid fibrils. The particular precursor protein that misfolds to form amyloid fibrils defines the amyloid type and predicts the patient’s clinical course. Several types of amyloid can infiltrate the heart, resulting in progressive diastolic and systolic dysfunction, congestive heart failure, and death.  Increased access to cardiovascular magnetic resonance imaging has led to a marked increase in referrals to St George’s University of London, London (Dr. Jason Dungu) of Caucasian patients with wild-type ATTR (senile systemic) amyloidosis and Afro-Caribbean patients with the hereditary ATTR V122I type. Both subtypes present predominantly as isolated cardiomyopathy. The differential diagnosis includes cardiac amyloid light-chain (AL) amyloidosis, which has a poorer prognosis and can be amenable to chemotherapy.

Clinical Presentation

Cardiac amyloidosis, irrespective of type, presents as a restrictive cardiomyopathy characterized by progressive diastolic and subsequently systolic biventricular dysfunction and arrhythmia.1 Key “red flags” to possible systemic amyloidosis include nephrotic syndrome, autonomic neuropathy (eg, postural hypotension, diarrhea), soft-tissue infiltrations (eg, macroglossia, carpal tunnel syndrome, respiratory disease), bleeding (eg, cutaneous, such as periorbital, gastrointestinal), malnutrition/cachexia and genetic predisposition (eg, family history, ethnicity). Initial presentations may be cardiac, with progressive exercise intolerance and heart failure. Other organ involvement, particularly in AL amyloidosis, may cloud the cardiac presentation (eg, nephrotic syndrome, autonomic neuropathy, pulmonary or bronchial involvement). Pulmonary edema is not common early in the disease process, but pleural and pericardial effusions and atrial arrhythmias are often seen. Syncope is common and a poor prognostic sign. It is typically exertional or postprandial as part of restrictive cardiomyopathy, sensitivity to intravascular fluid depletion from loop diuretics combined with autonomic neuropathy, or conduction tissue involvement (atrioventricular or sinoatrial nodes) or ventricular arrhythmia. The latter may rarely cause recurrent syncope. Disproportionate septal amyloid accumulation mimicking hypertrophic cardiomyopathy with dynamic left ventricular (LV) outflow tract obstruction is rare but well documented. Myocardial ischemia can result from amyloid deposits within the microvasculature. Atrial thrombus is common, particularly in AL amyloidosis

Diagnosis and Treatment

imaging – Cardiovascular Magnetic Resonance in Cardiac Amyloidosis*.

Cardiac amyloidosis can be diagnostically challenging. Cardiovascular magnetic resonance (CMR) can assess abnormal myocardial interstitium. In cardiac amyloidosis, CMR shows a characteristic pattern of global subendocardial late enhancement coupled with abnormal myocardial and blood-pool gadolinium kinetics. The findings agree with the transmural histological distribution of amyloid protein and the cardiac amyloid load.
 *AM Maceira; J Joshi; SK Prasad; J Charles Moon, et al. Royal Brompton Hospital, London;
The diagnosis of amyloidosis requires histological identification of amyloid deposits. Congo Red staining renders amyloid deposits salmon pink by light microscopy, with a characteristic apple green birefringence under polarized light conditions. Additional immunohistochemical staining for precursor proteins identifies the type of amyloidosis.  Ultimately, immunogold electron microscopy and mass spectrometry confer the greatest sensitivity and specificity for amyloid typing.
Treatment of cardiac amyloidosis is dictated by the amyloid type and degree of involvement. Consequently, early recognition and accurate classification are essential.
Novel diagnostic and surveillance approaches using imaging (echocardiography, cardiovascular magnetic resonance), biomarkers (brain natriuretic peptide [BNP], high-sensitivity troponin), new histological typing techniques, and current and future treatments, including approaches directly targeting the amyloid deposits.

Etiology

Amyloidosis is caused by the extracellular deposition of autologous protein in an abnormal insoluble β-pleated sheet fibrillary conformation—that is, as amyloid fibrils. More than 30 proteins are known to be able to form amyloid fibrils in vivo, which cause disease by progressively damaging the structure and function of affected tissues. Amyloid deposits also contain minor nonfibrillary constituents, including serum amyloid P component (SAP), apolipoprotein E, connective tissue components (glycosaminoglycans, collagen), and basement membrane components (fibronectin, laminin). Amyloid deposits can be massive, and cardiac or other tissues may become substantially replaced. Amyloid fibrils bind Congo red stain, yielding the pathognomonic apple-green birefringence under cross-polarized light microscopy that remains the gold standard for identifying amyloid deposits.

AL Amyloidosis

AL amyloidosis is caused by deposition of fibrils composed of monoclonal immunoglobulin light chains and is associated with clonal plasma cell or other B-cell dyscrasias. The spectrum and pattern of organ involvement is very wide, but cardiac involvement occurs in half of cases and is sometimes the only presenting feature. Cardiac AL amyloidosis may be rapidly progressive. Low QRS voltages, particularly in the limb leads, are common. Thickening of the LV wall is typically mild to moderate and is rarely >18 mm even in advanced disease. Cardiac AL amyloid deposition is accompanied by marked elevation of the biomarkers BNP and cardiac troponin, even at an early stage. Involvement of the heart is the commonest cause of death in AL amyloidosis and is a major determinant of prognosis; without cardiac involvement, patients with AL amyloidosis have a median survival of around 4 years, but the prognosis among affected patients with markedly elevated BNP and cardiac troponin (Mayo stage III disease) is on the order of 8 months.

Hereditary Amyloidoses

Mutations in several genes, such as transthyretin, fibrinogen, apolipoprotein A1, and apolipoprotein A2 can be responsible for hereditary amyloidosis, but by far the most common cause is variant ATTR amyloidosis (variant ATTR) caused by mutations in the transthyretin gene causing neuropathy and, often, cardiac involvement.

TTR gene mutation

 The most common is the Val122Ile mutation. In a large autopsy study that included individuals with cardiac amyloidosis, the TTR Val122Ile allele was present in 3.9% of all African Americans and 23% of African Americans with cardiac amyloidosis. Penetrance of the mutation is not truly known and is associated with a late-onset cardiomyopathy that is indistinguishable from senile cardiac amyloidosis.

Pathology, Presentation, and Management of Amyloidoses

More than 100 genetic variants of TTR are associated with amyloidosis. Most present as the clinical syndrome of progressive peripheral and autonomic neuropathy. Unlike wild-type ATTR or variant ATTR Val122Ile, the features of other variant ATTR include vitreous amyloid deposits or, rarely, deposits in other organs. Cardiac involvement in variant ATTR varies by mutations and can be the presenting or indeed the only clinical feature. For example, cardiac involvement is rare in variant ATTR associated with Val30Met (a common variant in Portugal or Sweden), but it is almost universal and develops early in individuals with variant ATTR due to Thr60Ala mutation (a mutation common in Ireland).

Senile Systemic Amyloidosis (Wild-Type ATTR)

Wild-type TTR amyloid deposits are found at autopsy in about 25% of individuals >80 years of age.  The prevalence of wild-type TTR deposits leading to the clinical syndrome of wild-type ATTR cardiac amyloidosis is unknown. Wild-type ATTR is a predominantly cardiac disease, and the only other significant extracardiac feature is a history of carpal tunnel syndrome, often preceding heart failure by 3 to 5 years. Extracardiac involvement is most unusual.
Both wild-type ATTR and ATTR due to Val122Ile are diseases of the >60-year age group and are often misdiagnosed as hypertensive heart disease. Wild-type ATTR has a strong male predominance, and the natural history remains poorly understood, but studies suggest a median survival of about 7 years from presentation. Recent developments in cardiac magnetic resonance (CMR), which have greatly improved detection of cardiac amyloid during life, suggest that wild-type ATTR is more common than previously thought: It accounted for 0.5% of all patients seen at the UK amyloidosis center until 2001 but now accounts for 7% of 1100 cases with amyloidosis seen since the end of 2009. There appears to be an association between wild-type ATTR and history of myocardial infarctions, G/G (Val/Val) exon 24 polymorphism in the alpha2-macroglobulin (alpha2M), and the H2 haplotype of the tau gene36; the association of tau with Alzheimer’s disease raises interesting questions as both are amyloid-associated diseases of aging.
ECG of a patient with cardiac AL amyloidosis showing small QRS voltages (defined as ≤6 mm height), predominantly in the limb leads and pseudoinfarction pattern in the anterior leads.
Echocardiography is characteristic. Typical findings include concentric ventricular thickening with right ventricular involvement, poor biventricular long-axis function with normal/near-normal ejection fraction and valvular thickening (particularly in wild-type or variant ATTR). Diastolic dysfunction is the earliest echocardiographic abnormality and may occur before cardiac symptoms develop. Biatrial dilatation in presence of biventricular, valvular, and interatrial septal thickening 53 is a useful clue to the diagnosis.
Transthoracic echocardiogram with speckle tracking. The red and yellow lines represent longitudinal motion in the basal segments, whereas the purple and green lines represent apical motion. This shows loss of longitudinal ventricular contraction at the base compared to apex.

Biomarkers.

High-sensitivity troponin is abnormal in >90% of cardiac AL patients, and the combination of BNP/NT-proBNP plus troponin measurements is used to stage and risk-stratify patients with AL amyloidosis at diagnosis. Very interestingly, the concentration of BNP/NT-proBNP in AL amyloidosis may fall dramatically within weeks after chemotherapy that substantially reduces the production of amyloidogenic light chains. The basis for this very rapid phenomenon, which is not mirrored by changes on echocardiography or CMR, remains uncertain, but a substantial fall is associated with improved outcomes.

Cardiac Magnetic Resonance.

CMR provides functional and morphological information on cardiac amyloid in a similar way to echocardiography, though the latter is superior for evaluating and quantifying diastolic abnormalities. An advantage of CMR is in myocardial tissue characterization. Amyloidotic myocardium reveals subtle precontrast abnormalities (T1, T2), but extravascular contrast agents based on chelated gadolinium provide the key information.

CMR with the classic amyloid global, subendocardial late gadolinium enhancement pattern in the left ventricle with blood and mid-/epimyocardium nulling together.
Recently, the technique of equilibrium contrast CMR has demonstrated much higher extracellular myocardial volume in cardiac amyloid than any other measured disease. It is anticipated that accurate measurements of the expanded interstitium in amyloidosis will prove useful in serial quantification of cardiac amyloid burden.
Sequential static images from a CMR TI scout sequence. As the inversion time (TI) increases, myocardium nulls first (arrow in image 3), followed by blood afterwards (arrow in image 6), implying that there is more gadolinium contrast in the myocardium than blood—a degree of interstitial expansion such that the “myocrit” is smaller than the hematocrit.

Tissue biopsy.

To confirm amyloidosis, including familial TTR amyloidosis, the demonstration of amyloid deposition on biopsied tissues is essential. With Congo red staining, amyloid deposits show a characteristic yellow-green birefringence under polarized light. Tissues suitable for biopsy include: subcutaneous fatty tissue of the abdominal wall, skin, gastric or rectal mucosa, sural nerve, and peritendinous fat from specimens obtained at carpal tunnel surgery. Sensitivity of endoscopic biopsy of gastrointestinal mucosa is around 85%; biopsy of the sural nerve is less sensitive. It is ideal to show that these amyloid deposits are specifically immunolabeled by anti-TTR antibodies.

Serum variant TTR protein.

TTR protein normally circulates in serum or plasma as a soluble protein having a tetrameric structure [Kelly 1998, Rochet & Lansbury 2000]. Normal plasma TTR concentration is 20-40 mg/dL (0.20-0.40 mg/mL).  Pathogenic mutations in TTR cause conformational change in the TTR protein molecule, disrupting the stability of the TTR tetramer, which is then more easily dissociated into pro-amyloidogenic monomers.

After immunoprecipitation with anti-TTR antibody, serum variant TTR protein can be detected by mass spectrometry. Approximately 90% of TTR variants so far identified are confirmed by this method. Mass shift associated with each variant TTR protein is indicated.

Molecular genetic testing.

  • TTR is the only gene in which mutations are known to cause familial TTR amyloidosis.
  • Identified in many individuals of different ethnic backgrounds; found in large clusters in Portugal, Sweden, and Japan.
  • The gene has four exons; and all the hitherto-identified mutations are in exons 2, 3, or 4.
GeneReviews designates a molecular genetic test as clinically available only if the test is listed in the GeneTests Laboratory Directory by either a US CLIA-licensed laboratory or a non-US clinical laboratory.
  • Molecular genetic testing of TTR by sequence analysis (may be preceded by targeted mutation analysis)
  • Although deletion/duplication testing is available clinically, no exonic or whole-gene deletions or duplications involving TTR have been reported to cause familial transthyretin amyloidosis.
  • However, with newly available deletion/duplication testing methods, it is theoretically possible that such mutations may be identified in affected individuals in whom prior testing by sequence analysis of the entire coding region was negative.
  • Predictive testing for at-risk asymptomatic adult family members requires prior identification of the disease-causing mutation in the family.
  • Prenatal diagnosis and preimplantation genetic diagnosis (PGD) for at-risk pregnancies require prior identification of the disease-causing mutation in the family.

Genetically Related (Allelic) Disorders

Familial euthyroid hyperthyroxinemia is caused by normal allelic variants in TTR, including Gly6Ser, Ala109Thr, Ala109Val, and Thr119Met (see Table 5) [Nakazato 1998, Benson 2001, Saraiva 2001]. The TTR protein binds approximately 15% of serum thyroxine. These mutations increase total serum thyroxine concentration because of their increased affinity for thyroxine, however, they increase neither free thyroxine nor free triiodothyronine. Therefore, individuals with these sequence variants develop no clinical symptoms (i.e., they are euthyroid).
Senile systemic amyloidosis (SSA; previously called senile cardiac amyloidosis) results from the pathologic deposition of wild-type TTR, predominantly in the heart. Pathologic deposits are also seen in the lungs, blood vessels, and the renal medulla of the kidneys [Westermark et al 2003]. SSA affects mainly the elderly but is rarely diagnosed during life.
Sensorimotor neuropathy and autonomic neuropathy progress over ten to 20 years. Various types of cardiac conduction block frequently appear. Cachexia is a common feature at the late stage of the disease. Affected individuals usually die of cardiac failure, renal failure, or infection.

Cardiac amyloidosis.

Cardiac amyloidosis, mainly characterized by progressive cardiomyopathy, has been reported with more than two thirds of TTR mutations. In some families with specific TTR mutations, such as Asp18Asn, Val20Ile, Pro24Ser, Ala45Thr, Ala45Ser, His56Arg, Gly57Arg, Ile68Leu, Ala81Thr, Ala81Val, His88Arg, Glu92Lys, Arg103Ser, Leu111Met, or Val122Ile, cardiomyopathy without peripheral neuropathy is a main feature of the disease.

Cardiac amyloidosis is usually late onset. Most individuals develop cardiac symptoms after age 50 years; cardiac amyloidosis generally presents with restrictive cardiomyopathy. The typical electrocardiogram shows a pseudoinfarction pattern with prominent Q wave in leads II, III, aVF, and V1-V3, presumably resulting from dense amyloid deposition in the anterobasal or anteroseptal wall of the left ventricle. The echocardiogram reveals left ventricular hypertrophy with preserved systolic function. The thickened walls present “a granular sparkling appearance.”
Among the mutations responsible for cardiac amyloidosis, Val122Ile is notable for its prevalence in African Americans. Approximately 3.0%-3.9% of African Americans are heterozygous for Val122Ile . The high frequency of Val122Ile partly explains the observation that in individuals in the US older than age 60 years, cardiac amyloidosis is four times more common among blacks than whites.

Leptomeningeal (oculoleptomeningeal) amyloidosis.

Amyloid deposition is seen in the pial and arachnoid membrane, as well as in the walls of vessels in the subarachnoid space associated with TTR mutations including Leu12Pro, Asp18Gly, Ala25Thr, Val30Gly, Ala36Pro, Gly53Glu, Gly53Ala, Phe64Ser, Tyr69His, or Tyr114Cys.  Individuals with leptomeningeal amyloidosis show CNS signs and symptoms including: dementia, psychosis, visual impairment, headache, seizures, motor paresis, ataxia, myelopathy, hydrocephalus, or intracranial hemorrhage. When associated with vitreous amyloid deposits, leptomeningeal amyloidosis is known as familial oculolepto-meningeal amyloidosis (FOLMA). In leptomeningeal amyloidosis protein concentration in the cerebrospinal fluid is usually high, and gadolinium-enhanced MRI typically shows extensive enhancement of the surface of the brain, ventricles, and spinal cord.

Genotype-Phenotype Correlations.

In subsets of families with the Val30Met mutation, considerable variation in phenotypic manifestations and age of onset is observed. It is hypothesized that genetic modifiers and non-genetic factors contribute to the pathogenesis and progression of familial TTR amyloidosis. The vast majority of individuals with familial TTR amyloidosis are heterozygous for a TTR mutation. It has been clinically and experimentally demonstrated that the normal allelic variant c.416C>T (Thr119Met) has a protective effect on amyloidogenesis in individuals who have the Val30Met mutation.

Cardiac amyloidosis is caused by Asp18Asn, Val20Ile, Pro24Ser, Ala45Thr, Ala45Ser, His56Arg, Gly57Arg, Ile68Leu, Ala81Thr, Ala81Val, His88Arg, Glu92Lys, Arg103Ser, Leu111Met, or Val122Ile. Peripheral and autonomic neuropathy are absent or less evident in persons with these mutations.
Leptomeningeal amyloidosis is associated with Leu12Pro, Asp18Gly, Ala25Thr, Val30Gly, Ala36Pro, Gly53Glu, Gly53Ala, Phe64Ser, Tyr69His, or Tyr114Cys.

Penetrance.

It is generally accepted that the penetrance is much higher in individuals in endemic foci than outside of endemic foci. In Portugal, cumulative disease risk in individuals with the Val30Met mutation is estimated at 80% by age 50 and 91% by age 70 years, whereas the risk in French heterozygotes is 14% by age 50 and 50% by age 70 years. In Sweden, the penetrance is much lower: 1.7% by age 30, 5% by age 40, 11% by age 50, 22% by age 60, 36% by age 70, 52% by age 80, and 69% by age 90, respectively.

Nomenclature

The neuropathy associated with TTR mutations, now called familial TTR amyloidosis, was formerly referred to as one of the following:
  • Familial amyloid polyneuropathy type I (or the Portuguese-Swedish-Japanese type)
  • Familial amyloid polyneuropathy type II (or the Indiana/Swiss or Maryland/German type)

Prevalence

The Val30Met mutation, found worldwide, is the most widely studied TTR variant and is responsible for the well-known large foci of individuals with TTR amyloid polyneuropathy in Portugal, Sweden, and Japan. Numerous families with various non-Val30Met mutations have also been identified worldwide.

 Small transthyretin (TTR) ligands as possible therapeutic agents in TTR amyloidoses.

Almeida MR, Gales L, Damas AM, Cardoso I, Saraiva MJ. Porto, Portugal.
Curr Drug Targets CNS Neurol Disord. 2005 Oct;4(5):587-96.
In transthyretin (TTR) amyloidosis TTR variants deposit as amyloid fibrils giving origin, in most cases, to peripheral polyneuropathy, cardiomyopathy, carpal tunnel syndrome and/or amyloid deposition in the eye. The amino acid substitutions in the TTR variants destabilize the tetramer, which may dissociate into non native monomeric intermediates that aggregate and polymerize in amyloid fibrils that further elongate. Since this is a multi-step process there is the possibility to impair TTR amyloid fibril formation at different stages of the process namely by tetramer stabilization, inhibition of fibril formation or fibril disruption. Based on the proposed mechanism for TTR amyloid fibril formation we discuss the action of some of the proposed TTR stabilizers such as derivatives of some NSAIDs (diflunisal, diclofenac, flufenamic acid, and derivatives) and the action of amyloid disrupters such as 4′-iodo-4′-deoxydoxorubicin (I-DOX) and tetracyclines. Among all these compounds, TTR stabilizers seem to be the most interesting since they would impair very early the process of amyloid formation and could also have a prophylactic effect.

Clusterin regulates transthyretin amyloidosis.

Lee KW, Lee DH, Son H, Kim YS, Park JY, et al.  Gyeongnam National University, South Korea
Biochem Biophys Res Commun 2009;388(2):256-60.   http://dx.doi.org/10.1016/j.bbrc.2009.07.166.
Clusterin has recently been proposed to play a role as an extracellular molecular chaperone, affecting the fibril formation of amyloidogenic proteins. The ability of clusterin to influence amyloid fibril formation prompted us to investigate whether clusterin is capable of inhibiting TTR amyloidosis. Here, we report that clusterin strongly interacts with wild-type TTR and TTR variants V30M and L55P under acidic conditions, and blocks the amyloid fibril formation of TTR variants. In particular, the amyloid fibril formation of V30M TTR in the presence of clusterin is reduced to level similar to wild-type TTR. We also demonstrated that clusterin is an effective inhibitor of L55P TTR amyloidosis, the most aggressive form of TTR diseases. The mechanism by which clusterin inhibits TTR amyloidosis appears to be through stabilization of TTR tetrameric structure.

Prognosis.

Cardiac amyloidosis in general has a poor prognosis, but this differs according to amyloid type and availability and response to therapy. Treatment may be classified as follows: supportive therapy (ie, modified heart-failure treatment including device therapy); therapies that suppress production of the respective amyloid fibril precursor protein (eg, chemotherapy in AL amyloidosis); and novel strategies to inhibit amyloid fibril formation or to directly target the amyloid deposits or stabilize the precursor protein (especially in ATTR with drugs such as tafamidis or diflunisal). Cardiac transplantation, although rarely feasible, can be very successful in carefully selected patients.

Reducing Amyloid Fibril Precursor Protein Production

Treatment of amyloidosis is currently based on the concept of reducing the supply of the respective amyloid fibril precursor protein. In AL amyloidosis, therapy is directed toward the clonal plasma cells using either cyclical combination chemotherapy or high-dose therapy with autologous stem cell transplantation.
The newer treatment options include bortezomib (a proteosome inhibitor)105 and the newer immunomodulatory drugs lenalidomide and pomalidomide. Bortezomib combinations appear to be especially efficient in amyloidosis with high rates of near-complete clonal responses, which appear to translate into early cardiac responses.106–108 Phase II (bortezomib in combination with cyclophosphamide or doxorubicin) and phase III (bortezomib, melphalan, and dexamethasone compared to melphalan and dexamethasone as front-line treatment) trials are underway.
AA amyloidosis is the only other type of amyloidosis in which production of the fibril precursor protein can be effectively suppressed by currently available therapies. Anti-inflammatory therapies, such as anti-tumor necrosis factor agents in rheumatoid arthritis, can substantially suppress serum amyloid A protein production, but very little experience has been obtained regarding cardiac involvement, which is very rare in this particular type of amyloidosis.
TTR is produced almost exclusively in the liver, and TTR amyloidosis has lately become a focus for novel drug developments aimed at reducing production of TTR through silencing RNA and antisense oligonucleotide therapies. ALN-TTR01, a systemically delivered silencing RNA therapeutic, is already in phase I clinical trial. Liver transplantation has been used as a treatment for variant ATTR for 20 years, to remove genetically variant TTR from the plasma. Although this is a successful approach in ATTR Val30Met, it has had disappointing results in patients with other ATTR variants, which often involve the heart. The procedure commonly results in progressive cardiac amyloidosis through ongoing accumulation of wild-type TTR on the existing template of variant TTR amyloid. The role of liver transplantation in non-Val30Met–associated hereditary TTR amyloidosis thus remains very uncertain.

Inhibition of Amyloid Formation

Amyloid fibril formation involves massive conformational transformation of the respective precursor protein into a completely different form with predominant β-sheet structure. The hypothesis that this conversion might be inhibited by stabilizing the fibril precursor protein through specific binding to a pharmaceutical has lately been explored in TTR amyloidosis. A key step in TTR amyloid fibril formation is the dissociation of the normal TTR tetramer into monomeric species that can autoaggregate in a misfolded form. In vitro studies identified that diflunisal, a now little used nonsteroidal anti-inflammatory analgesic, is bound by TTR in plasma, and that this enhances the stability of the normal soluble structure of the protein. Studies of diflunisal in ATTR are in progress. Tafamidis is a new compound without anti-inflammatory analgesic properties that has a similar mechanism of action. Tafamidis has just been licensed for neuropathic ATTR, but its role in cardiac amyloidosis remains uncertain, and clinical trial results are eagerly awaited. Higher-affinity “superstabilizers” are also in development.

Conclusion

Cardiac amyloidosis remains challenging to diagnose and to treat. Key “red flags” that should raise suspicion include clinical features indicating multisystem disease and concentric LV thickening on echocardiography in the absence of increased voltage on ECG; the pattern of gadolinium enhancement on CMR appears to be very characteristic. Confirmation of amyloid type is now possible in most cases through a combination of immunohistochemistry, DNA analysis, and proteomics. A variety of novel specific therapies are on the near horizon, with potential to both inhibit new amyloid formation and enhance clearance of existing deposits.

Future Prospects

Jeffery W. Kelly, the former Dean of Graduate Studies (2000-2008) and Vice President of Academic Affairs (2000-2006), currently is the Chairman of Molecular and Experimental Medicine and the Lita Annenberg Hazen Professor of Chemistry within the Skaggs Institute of Chemical Biology at The Scripps Research Institute in La Jolla, California.
The work on folding proteins by the Kelly Group focuses on
[1] understanding protein misfolding and aggregation and on developing both chemical
[2] and biological strategies
[3] to ameliorate diseases caused by protein misfolding and/or aggregation.
Besides studying the structural and energetic basis behind protein folding, his laboratory also studies the etiology of neurodegenerative diseases linked to protein aggregation, including Alzheimer’s disease, Parkinson’s Disease, and the familial gelsolin and transthyretin-based amyloidoses–publishing over 250 peer-reviewed papers in this area to date. He has also provided insight into genetic diseases associated with loss of protein function, such as lysosomal storage diseases.
Kelly has cofounded three biotechnology companies, FoldRx Pharmaceuticals (with Susan Lindquist), now owned by Pfizer, Proteostasis Therapeutics, Inc. (with Andrew Dillin and Richard Morimoto) (a private corporation) and Misfolding Diagnostics (with Xin Jiang and Justin Chapman; a private corporation). The Kelly laboratory discovered the first regulatory agency-approved drug that slows the progression of a human amyloid disease using a structure-based design approach. This drug, now called Tafamidis or Vyndaqel, slowed the progression of familial amyloid polyneuropathy in an 18 month placebo controlled trial and in an 18 month extension study sponsored by FoldRx Pharmaceuticals (acquired by Pfizer in 2010). Vyndaqel or Tafamidis  was approved for the treatment of Familial amyloid Polyneuropathy by the European Medicines Agency in late 2011. Kelly also discovered that diflunisal kinetically stabilizes transthyretin, enabling a placebo controlled clinical trial with it to ameliorate familial amyloid polyneuropathy–the results of which will be announced in 2013. Proteostasis Therapeutics, Inc. is developing first-in-class drugs that adapt the proteostasis network to ameliorate both loss-of-function misfolding diseases and gain-of-toxic function diseases linked to protein aggregation.
In addition to discovering the first drug that slows the progression of a human amyloid disease, the Kelly Laboratory is credited with demonstrating that transthyretin conformational changes alone are sufficient for amyloidogenesis, discovering the first example of functional amyloid in mammals, making major contributions toward understanding β-sheet folding, discovering the “enhanced aromatic sequon”–sequences that are more efficiently glycosylated by cells and sequences which stabilize the proteins that they are incorporated into as a consequence of N-glycosylation and was corresponding author on and contributed some of the key experimental data demonstrating that altering cellular proteostasis capacity has the potential to alleviate protein misfolding and aggregation diseases.
Native state kinetic stabilization as a strategy to ameliorate protein misfolding diseases: a focus on the transthyretin amyloidoses. Johnson SM, Wiseman RL, Sekijima Y, Green NS, Adamski-Werner SL, Kelly JW.  http://www.ncbi.nlm.nih.gov/pubmed/16359163
Small molecule-mediated protein stabilization inside or outside of the cell is a promising strategy to treat protein misfolding/misassembly diseases. Herein we focus on the transthyretin (TTR) amyloidoses and demonstrate that preferential ligand binding to and stabilization of the native state over the dissociative transition state raises the kinetic barrier of dissociation (rate-limiting for amyloidogenesis), slowing and in many cases preventing TTR amyloid fibril formation. Since T119M-TTR subunit incorporation into tetramers otherwise composed of disease-associated subunits also imparts kinetic stability on the tetramer and ameliorates amyloidosis in humans, it is likely that small molecule-mediated native state kinetic stabilization will also alleviate TTR amyloidoses.
Energetic characteristics of the new transthyretin variant A25T may explain its atypical central nervous system pathology.
Sekijima Y, Hammarström P, Matsumura M, Shimizu Y, Iwata M, Tokuda T, Ikeda S, Kelly JW.
Lab Invest. 2003 Mar;83(3):409-17.   http://www.ncbi.nlm.nih.gov/pubmed/12649341
Transthyretin (TTR) is a tetrameric protein that must misfold to form amyloid fibrils. Misfolding includes rate-limiting tetramer dissociation, followed by fast tertiary structural changes that enable aggregation. Amyloidogenesis of wild-type (WT) TTR causes a late-onset cardiac disease called senile systemic amyloidosis. The aggregation of one of > 80 TTR variants leads to familial amyloidosis encompassing a collection of disorders characterized by peripheral neuropathy and/or cardiomyopathy. Prominent central nervous system (CNS) impairment is rare in TTR amyloidosis. Herein, we identify a new A25T TTR variant in a Japanese patient who presented with CNS amyloidosis at age 42 and peripheral neuropathy at age 44. The A25T variant is the most destabilized and fastest dissociating TTR tetramer published to date, yet, surprising, disease onset is in the fifth decade. Quantification of A25T TTR in the serum of this heterozygote reveals low levels relative to WT, suggesting that protein concentration influences disease phenotype. Another recently characterized TTR CNS variant (D18G TTR) exhibits strictly analogous characteristics, suggesting that instability coupled with low serum concentrations is the signature of CNS pathology and protects against early-onset systemic amyloidosis. The low A25T serum concentration may be explained either by impaired secretion from the liver or by increased clearance, both scenarios consistent with A25T’s low kinetic and thermodynamic stability. Liver transplantation is the only known treatment for familial amyloid polyneuropathy. This is a form of gene therapy that removes the variant protein from serum preventing systemic amyloidosis. Unfortunately, the choroid plexus would have to be resected to remove A25T from the CSF-the source of the CNS TTR amyloid. Herein we demonstrate that small-molecule tetramer stabilizers represent an attractive therapeutic strategy to inhibit A25T misfolding and CNS amyloidosis. Specifically, 2-[(3,5-dichlorophenyl)amino]benzoic acid is an excellent inhibitor of A25T TTR amyloidosis in vitro.
Prevention of Transthyretin Amyloid Disease by Changing Protein Misfolding Energetics
Per Hammarström*, R. Luke Wiseman*, Evan T. Powers, Jeffery W. Kelly†
Science 31 Jan 2003; 299(5607):713-716    http://dx.doi.org/10.1126/science.1079589
Genetic evidence suggests that inhibition of amyloid fibril formation by small molecules should be effective against amyloid diseases. Known amyloid inhibitors appear to function by shifting the aggregation equilibrium away from the amyloid state. Here, we describe a series of transthyretin amyloidosis inhibitors that functioned by increasing the kinetic barrier associated with misfolding, preventing amyloidogenesis by stabilizing the native state. The trans-suppressor mutation, threonine 119 → methionine 119, which is known to ameliorate familial amyloid disease, also functioned through kinetic stabilization, implying that this small-molecule strategy should be effective in treating amyloid diseases.
R104H may suppress transthyretin amyloidogenesis by thermodynamic stabilization, but not by the kinetic mechanism characterizing T119 interallelic trans-suppression.
Sekijima Y, Dendle MT, Wiseman RL, White JT, D’Haeze W, Kelly JW.
Amyloid. Jun 2006;13(2):57-66.    http://www.ncbi.nlm.nih.gov/pubmed/16911959
The tetrameric protein transthyretin (TTR) forms amyloid fibrils upon dissociation and subsequent monomer misfolding, enabling misassembly. Remarkably, the aggregation of one of over 100 destabilized TTR variants leads to familial amyloid disease. It is known that trans-suppression mediated by the incorporation of T119M subunits into tetramers otherwise composed of the most common familial variant V30M, ameliorates disease by substantially slowing the rate of tetramer dissociation, a mechanism referred to as kinetic stabilization of the native state. R104H TTR has been reported to be non-pathogenic, and recently, this variant has been invoked as a trans-suppressor of amyloid fibril formation. Here, we demonstrate that the trans-suppression mechanism of R104H does not involve kinetic stabilization of the tetrameric structure, instead its modest trans-suppression most likely results from the thermodynamic stabilization of the tetrameric TTR structure. Thermodynamic stabilization increases the fraction of tetramer at the expense of the misfolding competent monomer decreasing the ability of TTR to aggregate into amyloid fibrils. As a consequence of this stabilization mechanism, R104H may be capable of protecting patients with modestly destabilizing mutations against amyloidosis by slightly lowering the overall population of monomeric protein that can misfold and form amyloid.
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Accurate Identification and Treatment of Emergent Cardiac Events

Posted in Atherogenic Processes & Pathology, Biomarkers & Medical Diagnostics, Cardiac & Vascular Repair Tools Subsegment, Cardiovascular Pharmacogenomics, Cell Biology, Signaling & Cell Circuits, Computational Biology/Systems and Bioinformatics, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Frontiers in Cardiology and Cardiovascular Disorders, Genome Biology, Genomic Testing: Methodology for Diagnosis, Health Economics and Outcomes Research, International Global Work in Pharmaceutical, ISO 10993 for Product Registration: FDA & CE Mark for Development of Medical Devices and Diagnostics, Medical Imaging Technology, Image Processing/Computing, MRI, CT, Nuclear Medicine, Ultra Sound, Molecular Genetics & Pharmaceutical, Nutritional Supplements: Atherogenesis, lipid metabolism, Personalized and Precision Medicine & Genomic Research, Pharmaceutical Analytics, Pharmaceutical Industry Competitive Intelligence, Pharmacotherapy of Cardiovascular Disease, Population Health Management, Genetics & Pharmaceutical, Population Health Management, Nutrition and Phytochemistry, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Stem Cells for Regenerative Medicine, Technology Transfer: Biotech and Pharmaceutical, tagged , , , , , , , , , , , on March 15, 2013| 9 Comments »

Accurate Identification and Treatment of Emergent Cardiac Events

Author: Larry H Bernstein, MD, FCAP
In the immediately preceding article, I discussed the difficulties in predicting long-term safety for developing drugs, and the cost of failure in early identification.

It is not the same scale of issue as for the patient emergently presenting to the ED. Despite enormous efforts to reduce the development of and the complications of acute ischemia related cardiac events, the accurate diagnosis of the patient presenting to the emergency room is still, as always, reliant on clinical history, physical examination, effective use of the laboratory, and increasingly helpful imaging technology. The main issue that we have a consensus agreement that PLAQUE RUPTURE is not the only basis for a cardiac ischemic event. The introduction of  high sensitivity troponin tests has made it no less difficult after throwing out the receiver-operator characteristic curve (ROC) and assuming that any amount of cardiac troponin released from the heart is pathognomonic of an acute ischemic event.  This has resulted in a consensus agreement that

  • ctn measurement at a coefficient of variant (CV) measurement in excess of 2 Std dev of the upper limit of normal is a “red flag”
  • signaling AMI? or other cardiomyopathic disorder

This is the catch.  The ROC curve established AMI in ctn(s) that were accurate for NSTEMI – (and probably not needed with STEMI or new Q-wave, not previously seen) –

  1. ST-depression
  2. T-wave inversion
    • in the presence of other findings
    • suspicious for AMI

Wouldn’t it be nice if it was like seeing a robin on your lawn after a harsh winter?  Life isn’t like that.  When acute illness hits the patient may well present with ambiguous findings.   We are accustomed to relying on

  1. clinical history
  2. family history
  3. co-morbidities, eg., diabetes, obesity, limited activity?, diet?
    1. stroke and/or peripheral vascular disease
    2. hypertension and/or renal vascular disease
    3. aortic atherosclerosis or valvular heart disease
      • these are evidence, and they make up syndromic classes
  4. Electrocardiogram – 12 lead EKG (as above)
  5. Laboratory tests
    1. isoenzyme MB of creatine kinase (CK)… which declines after 12-18 hours
    2. isoenzyme-1 of LD if the time of appearance is > day-1 after initial symptoms (no longer used)
    3. cardiac troponin cTnI or cTnT
      • genome testing
      • advanced analysis of EKG

This may result in more consults for cardiologists, but it lays the ground for better evaluation of the patient, in the long run.  When you look at the amount of information that has to be presented to the physician, there is serious need for improvement in the electronic medical record to benefit the patient and the caregivers.  Recently, we have a publication on a new test that has been evaluated, closely related to the C-reactive protein (CRP), a test that has generated much discussion over the effect of treatment for patients who have elevated CRP in the absence of increased LDL cholesterol, diabetes, or obvious atherosclerotic comorbidities.  The serum pentraxin 3 test is related to cell mediated immunity, and an evaluation has been published in the Journal of Investigative Medicine.

Journal of Investigative Medicine Feb 2013; 61 (2): 278–285.
http://dx.doi.org/10.231/JIM.0b013e31827c2971

Serum Pentraxin 3 Levels Are Associated With the Complexity and Severity of Coronary Artery Disease in Patients With Stable Angina Pectoris
Karakas, Mehmet Fatih MD*; Buyukkaya, Eyup MD*; Kurt, Mustafa MD*; et al.
From the Departments of Cardiology and,Clinical Biochemistry, Mustafa Kemal University, Tayfur Ata Sokmen Medical School, Hatay, Turkey.
Reprints: Mehmet Fatih Karakas, MD, Antakya 31005, Turkey. E-mail: mfkarakas@hotmail.com.

Abstract
Background: Atherosclerosis is a complex inflammatory process. Although pentraxin 3 (PTX-3), a newly identified inflammatory marker, was associated with adverse outcomes in stable angina pectoris,

  • an association between PTX-3 and the complexity of coronary artery disease (CAD) has not been reported.

The aim of the present study is to assess

  • the association between the level of PTX-3 and
  • the complexity and severity of CAD assessed with
  • SYNTAX and Gensini scores in patients with stable angina pectoris.

Methods: The study population is 2 groups:

  • 161 patients with anginal symptoms and evidence of ischemia
    • who underwent coronary angiography and
  • 50 age- and sex- matched control subjects without evidence of ischemia .

Patients were grouped into 3 groups according to the complexity and severity of coronary lesions

  • assessed by the SYNTAX score (30 patients with a SYNTAX score of 0 were excluded).

Serum PTX-3 and high-sensitivity C-reactive protein (hs-CRP) levels were measured in both groups.

Results: The PTX-3 levels demonstrated

  • an increase from low to high SYNTAX groups (r = 0.72, P < 0.001).

Whereas the low SYNTAX group had statistically significantly higher PTX-3 levels when compared with the control group (0.50 ± 0.01 vs 0.24 ± 0.01 ng/mL, P < 0.001),

  • the hs-CRP levels were not different (0.81 ± 0.42 vs 0.86 ± 0.53 mg/dL, P = 0.96).
  • but  the intermediate SYNTAX group had higher hs-CRP levels compared with the low SYNTAX group (1.3 ± 0.66 vs 0.86 ± 0.53 mg/dL, P = 0.002).

Serum PTX-3 levels and hs-CRP levels were both correlated with the SYNTAX scores and Gensini scores (for SYNTAX: r = 0.87 [P < 0.001] and r = 0.36 [P = 0.01]; for Gensini: r = 0.75 [P < 0.001] and r = 0.27 [P = 0.002], respectively), and

  • according to the results of univariate and multivariate analyses, for “intermediate and high” SYNTAX scores, age, diabetes mellitus, low-density lipoprotein cholesterol, hs-CRP, and PTX-3
  • were found to be independent predictors, whereas
  • for the presence of “high” SYNTAX score only PTX-3 was found to be an independent predictor.
  • The receiver operating characteristic curve analysis further revealed that the PTX-3 level was
    • a strong indicator of high SYNTAX score with an area under the curve of 0.91 (95% confidence interval, 0.86–0.96).

Conclusions: Pentraxin 3, a novel inflammatory marker, was more tightly associated with the complexity and severity of CAD than hs-CRP and

    • it was found to be an independent predictor for high SYNTAX score.

The association between atherosclerosis and inflammation has been more understood during recent years. Currently, atherosclerosis is considered as a complex inflammatory process in which

    • leukocytes and inflammatory markers are involved.1

Several inflammatory markers

  1.  high-sensitivity C-reactive protein (hs-CRP),
  2. fibrinogen, and
  3. complement C3…. are associated with cardiovascular events.1–5

Pentraxin 3 (PTX-3), that resembles CRP both in structure and function,1 is produced both by

  • hematopoietic cells such as macrophages, dendritic cells, neutrophils, and by
  • nonhematopoietic cells such as fibroblasts and vascular endothelial cells.2

Plasma PTX-3 levels may be elevated in patients with

  1. vasculitis,6
  2. acute myocardial infarction,7,8 and
  3. systemic inflammation or sepsis,9
  4. psoriasis,
  5. unstable angina pectoris, and
  6. heart failure.10–13

Dubin et al14 reported that PTX-3 levels are associated with with adverse outcomes in stable angina pectoris (SAP). Despite reports about the association of PTX-3 and coronary artery disease (CAD),

an association between the level of PTX-3 and the complexity and severity of CAD is not established.15,16 Thus, the aim of this study was

  • to assess the association between the level of PTX-3 and the complexity and severity of CAD assessed with SYNTAX and Gensini scores in SAP patients.

MATERIALS AND METHODS

Of 211 patients were prospectively recruited,  161 SAP patients with evidence of ischemia (positive treadmill or myocardial perfusion scan) underwent coronary angiography for suspected CAD, and 50 age- and sex- matched outpatient subjects with a negative treadmill or myocardial perfusion scan test were taken as the control group. Patients were excluded if they had

  •  acute coronary syndrome
  • history of previous myocardial infarction;
  • coronary artery bypass grafting or percutaneous coronary intervention;
  • secondary hypertension (HT);
  • renal failure;
  • hepatic failure;
  • chronic obstructive lung disease and/or
  • manifest heart disease, such as
    • cardiac failure (left ventricular ejection fraction <50%),
    • atrial fibrillation, and
    • moderate to severe cardiac valve disease; and
    • SYNTAX score of zero

Similarly, patients were excluded with

  • infection,
  • acute stress, or chronic systemic inflammatory disease and
  • those who had been receiving medications affecting the number of leukocytes .

Thirty patients were excluded from the study because the coronary angiograms revealed normal coronary arteries (SYNTAX score of 0). All the participants included in the study were informed about the study, and they voluntarily consented to participate. The Serum PTX-3 level was measured on blood samples collected after 12-hour fast just prior to coronary angiography and kept at −80°C until the assays were performed. PTX3 was measured by enzyme immunoassay (EIA) using quantitative kit (human PTX-3/TSG-14 immunoassay, DPTX30; R&D Systems, Inc, Minneapolis, MN). The intra-assay and interassay coefficients of variation ranged from 3.8% to 4.4% and 4.1% to 6.1%, respectively (minimum detectable concentration, 0.025 ng/mL). High-sensitivity CRP was measured in serum by EIA (Immage hs-CRP EIA Kit; Beckman Coulter Inc, Brea, CA). Transthoracic echocardiography was performed, and biplane Simpson’s ejection fraction (%) was calculated before coronary angiography. Hypertension was defined as having at least 2 blood pressure measurements greater than 140/90 mm Hg or using antihypertensive drugs, whereas diabetes mellitus (DM) was defined as having at least 2 fasting blood sugar measurements greater than 126 mg/dL or using antidiabetic drugs. Smoking was categorized into current smokers and nonsmokers. Nonsmokers included ex-smokers who had quit smoking for at least 6 months before the study. Body mass index (BMI) values were calculated based on the height and weight of each patient. Medications used before the coronary angiography were noted. The study was approved by the local ethics committee.
SYNTAX and Gensini Scores
To grade the complexity of CAD, the SYNTAX score was used. Each coronary lesion with a stenosis diameter of 50% or greater in vessels of 1.5 mm or greater was scored. Parameters used in the SYNTAX scoring are shown in Table 1. The latest online updated version (2.11) was used in the calculation of the SYNTAX scores (www.syntaxscore.com).17 The SYNTAX score was classified as follows:

  1. low SYNTAX score (≤22),
  2. intermediate SYNTAX score (23–32)
  3. high SYNTAX score (≥33).

Table 1   http://images.journals.lww.com/jinvestigativemed/LargeThumb.00042871-201302000-00007.TT1.jpeg

The severity of CAD was determined by the Gensini score, which

  • measures the extent of coronary stenosis according to degree and location.18

In the Gensini scoring system,

  • larger segments are more heavily weighted ranging from 0.5 to 5.0
    • left main coronary artery × 5;
    • proximal segment of the left anterior descending coronary artery [LAD] × 2.5;
    • proximal segment of the circumflex artery × 2.5;
    • midsegment of the LAD × 1.5;
    • right coronary artery distal segment of the LAD,
    • posterolateral artery, and obtuse marginal artery × 1;
    • and others × 0.5.

The narrowing of the coronary artery lumen is rated

  1. 2 for 0% to 25% stenosis,
  2. 4 for 26% to 50%,
  3. 8 for 51% to 75%,
  4. 16 for 76% to 90%,
  5. 32 for 91% to 99%,
  6. 64 for 100%.

The Gensini index is the sum of the total weights for each segment. All angiographic variables of the SYNTAX and Gensini score were computed by

  • 2 experienced cardiologists who were blinded to the procedural data and clinical outcomes.

The final decision was reached by consensus when a conflict occurred.The number of diseased vessels with

  • greater than 50% luminal stenosis was scored from 1 to 3 (namely, 1-, 2-, or 3-vessel disease), and
  • a lesion greater than 50% in the left main coronary artery was regarded as a 2-vessel disease.

Statistical Analyses

Statistical analyses were conducted with SPSS 17 (SPSS Inc, Chicago, IL) software package program.
Continuous variables were expressed as mean ± SD or median ± interquartile range values, whereas categorical variables were presented as percentages.
The differences between normally distributed numeric variables were evaluated by Student t test or 1-way analysis of variance, whereas

  • non–normally distributed variables were analyzed by Mann-Whitney U test or Kruskal-Wallis variance analysis as appropriate.

χ2 Test was used for the comparison of categorical variables. Pearson test was used for correlation analysis.
To determine the independent predictors of “intermediate and high” SYNTAX scores and only “high” SYNTAX scores,

  • 2 different sets of univariate and multivariate analyses were performed
    • (in the first model SYNTAX cutoff was 22, whereas
    • in the second model SYNTAX cutoff was 33).

The standardized parameters that were found to have a significance (P < 0.10) in the univariate analysis were evaluated by stepwise logistic regression analysis.
Ninety-five percent confidence interval (CI) and odds ratio (OR) per SD increase were presented together. Interobserver and intraobserver variability for SYNTAX scores

  • was done by Bland-Altman analysis.

An exploratory evaluation of additional cut points was performed using the receiver operating characteristic (ROC) curve analysis.
All the P values were 2-sided, and a P < 0.05 was considered as statistically significant.
RESULTS
Baseline Characteristics
In total, 181 patients (50.2 ± 6.5 years, 52.5% were composed of males) were included in the study. Baseline clinical, angiographic, and laboratory characteristics of the patients
relative to SYNTAX score groups are shown in Table 2. Age, sex, HT, DM, BMI, and medication were not different between the groups. Baseline clinical and laboratory characteristics
of patients according to PTX-3 quartiles are shown in Table 3. The Bland-Altman analysis revealed that the degrees of intraobserver and interobserver variability for SYNTAX score
and Gensini score readings were 5% and 6% for SYNTAX and 8% and 9% for Gensini, respectively.
Table 2   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.TT2.jpeg
Table 3   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.TT3.jpeg

The PTX-3 levels demonstrated an increase from the low SYNTAX group to the high SYNTAX group (r = 0.87, P < 0.001).
The low SYNTAX group had statistically significantly higher PTX-3 levels when compared with the control group (0.50 ± 0.01 vs 0.24 ± 0.01 ng/mL, P < 0.001); similarly,
the PTX-3 levels were higher in the high SYNTAX group than in both

  • the intermediate SYNTAX group (0.84 ± 0.08 vs 0.55 ± 0.01 ng/mL, P < 0.001) and
  • the low SYNTAX group (0.84 ± 0.08 vs 0.50 ± 0.01 ng/mL, P < 0.001).
  • there was no difference in levels of PTX-3 between the low and the intermediate SYNTAX group (0.50 ± 0.01 vs 0.55 ± 0.01 ng/mL, P = 0.09).

On the other hand, there was no difference in levels of hs-CRP between the control and the low SYNTAX group (0.81 ± 0.42 vs 0.86 ± 0.53 mg/dL, P = 0.96).
The intermediate SYNTAX group had statistically significantly higher hs-CRP levels

  • compared with the low SYNTAX group (1.3 ± 0.66 vs 0.86 ± 0.53 mg/dL, P = 0.002);
  • the hs-CRP levels were not different between the high SYNTAX group
    • and the intermediate SYNTAX group. (1.3 ± 0.66 vs 1.3 ± 0.43 mg/dL, P = 0.99).

Univariate correlation analysis revealed a positive correlation between serum PTX-3 levels and hs-CRP levels with

  • the SYNTAX and Gensini scores
    • for SYNTAX: r = 0.87 [P < 0.001] and r = 0.36 [P = 0.01];
    • for Gensini: r = 0.75 [P < 0.001] and r = 0.27 [P = 0.002],  (Fig. 1).

In addition to that, the Gensini and SYNTAX scores are found to be well correlated with each other (r = 0.80, P < 0.001).
When the SYNTAX score was taken as continuous variable, multivariate linear regression analysis revealed that

  • the SYNTAX score was correlated with PTX-3 and hs-CRP (for PTX-3: β = 0.84 [P < 0.001]; hs-CRP: β =0.08 [P = 0.032]).

Figure 1   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.FF1.jpeg

For determining the predictors of intermediate and high SYNTAX scores and only-high SYNTAX scores,

  • 2 different sets of univariate and multivariate analyses were performed among the patients who underwent coronary angiography.

For predicting the intermediate and high SYNTAX scores, the SYNTAX score was dichotomized into

  • high (score ≥22) and
  • low (<22) groups,

whereas for predicting the only-high SYNTAX scores, the SYNTAX score was dichotomized into

  • 2 groups with a score of 33 or greater and a score of less than 33.

In the first multivariate analysis (where SYNTAX cutoff was 22), the parameters showing significance in the univariate analysis

  • age,
  • sex,
  • HT,
  • DM,
  • low-density lipoprotein cholesterol [LDL-C],
  • hs-CRP,
  • PTX-3

were evaluated by multivariate analysis to determine the

  • independent predictors of intermediate and high SYNTAX scores.

In the univariate analysis, higher values of

  • age (OR, 1.5 [95% CI, 1.1–2.0]; P = 0.01),
  • LDL-C (OR, 1.3 [95% CI, 0.98–1.8]; P = 0.068),
  • hs-CRP (OR, 2.6 [95% CI, 1.8–3.8]; P < 0.001), and
  • PTX-3 (OR, 13.6 [95% CI, 6.4–28.9]; P < 0.001)
    • were associated with higher SYNTAX scores,
  • HT (OR, 0.44 [95% CI, 0.24–0.80]; P = 0.008) and
  • DM (OR, 0.48 [95% CI, 0.25–0.91]; P = 0.02)
    • were associated with lower SYNTAX scores.

In the multivariate analysis – age, DM, LDL-C, hs-CRP, and PTX-3 – were found to be

  • independent predictors of “intermediate to high” SYNTAX score (Table 4).

Increased

  • age (OR, 2.5 [95% CI, 1.3–4.8]; P = 0.007),
  • LDL-C (OR, 2.8 [95% CI, 1.5–5.2]; P = 0.001),
  • hs-CRP (OR, 3.3 [95% CI, 1.8–6.1]; P < 0.001), and
  • PTX-3 (OR, 35.4 [95% CI, 10.1–123.6]; P < 0.001)
    • were associated with increased SYNTAX scores,

whereas DM (OR, 0.08 [95% CI, 0.02–0.33]; P < 0.001) was associated with lower SYNTAX score (Table 4).

In the second univariate and multivariate analyses (where SYNTAX cutoff was 33),

  • the parameters that showed significance in the univariate analysis were age, LDL-C, glucose, hs-CRP, and PTX-3.
  • In the univariate analysis, increased
    • age (OR, 1.5 [95% CI, 1.0–2.3]; P = 0.05),
    • LDL-C (OR, 1.5 [95% CI, 0.97–2.2]; P = 0.07),
    • hs-CRP (OR, 1.4 [95% CI, 0.97–2.1]; P = 0.072), and
    • PTX-3 (OR, 18.5 [95% CI, 6.6–51.8]; P < 0.001)
      • were found to be associated with increased SYNTAX scores.

When these parameters were evaluated with multivariate analysis, only PTX-3 (OR, 18.4 [95% CI, 6.2–54.2]; P < 0.001)

    • was found to be an independent predictor for high SYNTAX score (Table 4).

Table 4   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.TT4.jpeg

The ROC curve analysis further revealed that the PTX-3 level was a strong indicator of high SYNTAX score with

  • an area under the curve (AUC) of 0.91 (95% CI, 0.86–0.96) (Fig. 2).

The optimal cutoff of PTX-3 for the high SYNTAX score was 0.75 ng/mL.
Sensitivity, specificity, positive predictive value, and negative predictive value to identify high SYNTAX score for the PTX-3 level

  • were 90%, 84%, 97%, and 60%, respectively.
  • the ROC curve analysis of PTX-3 for intermediate-high SYNTAX score revealed that the AUC value was 0.82 (95% CI, 0.75–0.89).

The optimal threshold of PTX-3 level that

  • maximized the combined specificity and sensitivity to predict
    • intermediate to high SYNTAX score was 0.73 ng/mL.

For the cutoff value of 0.73 ng/mL, sensitivity, specificity, positive predictive value, and negative predictive value

  • to identify intermediate-high SYNTAX score were 56%, 98%, 97%, and 56%, respectively.

Figure 2   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.FF2.jpeg

In the ROC analysis of hs-CRP for high SYNTAX scores, the AUC value was found to be 0.68 (95% CI, 0.59–0.77; P < 0.001).
The optimal threshold of hs-CRP that maximized the combined specificity and sensitivity to predict for high SYNTAX scores was 0.89 mg/dL.
Similarly, the ROC analysis of hs-CRP for the intermediate-high SYNTAX scores revealed an AUC of 0.74 (95% CI, 0.65–0.83; P = 0.001).
The cutoff value of hs-CRP to predict the intermediate-high SYNTAX scores with a maximized sensitivity and specificity was 0.66 mg/dL.
DISCUSSION
In this particular study, we investigated the relationship between the serum PTX-3 level and the severity of CAD

  • assessed by SYNTAX and Gensini scores in patients with SAP.

The PTX-3, was significantly higher than control group in the patients with CAD, and the serum PTX-3 levels

  • were associated with the SYNTAX and Gensini scores.

When compared with the hs-CRP, the PTX-3 was found to be more tightly associated with the complexity and severity of CAD in the patients with SAP.
Pentraxin 3, an acute-phase reactant that is functionally and structurally similar to CRP,1 is produced both by different kinds of cells such as

  • macrophages, dendritic cells, neutrophils, fibroblasts, and vascular endothelial cells.2
  • Pentraxin 3 is released following the inflammatory stimuli19; therefore, it may reflect the local inflammatory status in tissues.20

Serum PTX-3 levels were shown to be elevated in patients with

  • vasculitis,6 acute myocardial infarction,7,8 and systemic inflammation or sepsis,9 psoriasis, unstable angina pectoris, and heart failure.10–13

Higher PTX3 levels were reported to be associated with worse cardiovascular outcomes

  1. after acute coronary syndromes,8,21
  2. in the elderly people without known cardiovascular disease22 and
  3. associated with overall mortality in patients with stable coronary disease,
  4. independent of systemic inflammation.14

There are 2 reports investigating the association of PTX-3 level and the atherosclerotic burden.15,16 In one of these reports,

  • Knoflach et al.15 took B-mode ultrasonography as the atherosclerosis index.

They did not provide any information about coronary anatomy, and in the other report, Soeki et al.16 evaluated 40 patients who

  • underwent coronary angiography and measured their Gensini scores.

However, in none of the studies were the SYNTAX score and Gensini score used together to assess the degree of coronary atherosclerotic burden.
To our knowledge, this is the first report that showed the association of PTX-3 levels with the complexity and severity of CAD assessed by

  • SYNTAX and Gensini scores in patients with stable coronary disease.

Chronic low-grade inflammation has been thought to play a major role in the pathogenesis of atherosclerosis.23,24 Previous studies have reported that

  • levels of inflammatory markers such as hs-CRP, interleukin 6, and so on were increased in atherosclerosis.25

In the present study, both the SYNTAX and the Gensini scores were found to be correlated with serum PTX-3 and hs-CRP levels,

  • which in turn might reflect the degree of inflammation.

The SYNTAX score is an important tool in the classification of complex CAD26 and can give predictive information about short- and long-term outcomes

  • in patients with stable CAD who undergo percutaneous coronary intervention.27–30

Although the SYNTAX score is currently used for assessing the angiographic complexity of CAD rather than the severity of coronary atherosclerotic burden,

  • because more complex lesions tend to have more atherosclerotic burden,
  • the SYNTAX scores may also reflect the severity of coronary atherosclerotic burden.

The Gensini score, a well-known and widely used scoring system to evaluate the severity of CAD,18 was measured and

  • found to be well correlated with the SYNTAX score,
    • which supports the idea that angiographically more complex lesions tend to have more atherosclerotic burden.

When compared with the hs-CRP,

  • the PTX-3 seems to be more tightly associated with coronary disease burden (r = 0.36 vs r = 0.87).

We found out that the serum PTX-3 levels were higher than those in the control group, even in the low SYNTAX group.
On the other side, the serum hs-CRP levels were not different in the control and the low SYNTAX groups.
It was reported that the leukocytes mainly found in the coronary artery lumen are the neutrophils.31
It is also known that PTX-3 is stored in specific granules of neutrophils and released in response to inflammatory signals.32
The reason why serum PTX-3 levels seem more tightly associated with the coronary disease burden

  • when compared with serum hs-CRP levels may be the association of the
  • on-site presence of neutrophils and local inflammatory signal–triggered release of  PTX-3.

On the other hand, some human studies revealed that PTX-3 was produced more in areas of atherosclerosis and may contribute to its pathogenesis.31
Some other studies suggested that PTX-3 may be part of a protective mechanism in

  • vascular repair via inhibiting fibroblast growth factor 2 or some other growth factors responsible for smooth muscle proliferation.33,34

But still, the exact role of PTX-3 in the pathophysiology of atherosclerosis seems to be obscure for the time being. It is well established that atherosclerosis
has an inflammatory background in most of the cases. In addition to that, high blood CRP level is known as an indicator of future cardiovascular disease risk
even in healthy individuals.35 According to the results of univariate and multivariate analyses, for intermediate and high SYNTAX scores,

  1. age, DM, LDL-C, hs-CRP, and PTX-3 were found to be independent predictors, whereas for the presence of
  2. high SYNTAX score, only PTX-3 was found to be an independent predictor.

Because of the tighter association with atherosclerotic burden and the on-site vascular presence,

    • PTX-3 may be a promising candidate marker for vascular inflammation and future cardiovascular events.

LIMITATIONS
The major limitation of the current study is the number of patients included. It would be better to include more patients to increase the statistical power.

Besides, the SYNTAX and Gensini scores give us an idea about the complexity and severity of coronary atherosclerosis; however,
with coronary angiography alone, it is not possible to understand the extent of coronary plaque. In addition to that, the coronary anatomy of the
control group was not known, which was another limitation. Our selected population was free of other confounders of systemic inflammation, and
we did not have data about inflammatory markers other than hs-CRP, such as interleukin 6, tumor necrosis factor α, and so on, which may be accepted
as a limitation. Another limitation of the current study is that because there was no long-term follow-up of the patients, it did not provide any prognostic
data in terms of future cardiovascular events.
CONCLUSIONS
Pentraxin 3, a novel inflammatory marker, is associated with the complexity and severity of the CAD assessed by the SYNTAX and the Gensini scores in patients with SAP and seems to be more tightly associated with coronary atherosclerotic burden than hs-CRP.

REFERENCES

1. Hansson GK. Inflammation, atherosclerosis, and coronary artery disease. N Engl J Med. 2005; 352: 1685–1695.
2. Brown DW, Giles WH, Croft JB. White blood cell count: an independent predictor of coronary heart disease mortality among a national cohort. J Clin Epidemiol. 2001; 54: 316–322.
3. Kannel WB, Anderson K, Wilson PW. White blood cell count and cardiovascular disease. Insights from the Framingham Study. JAMA. 1992; 267: 1253–1256.
4. Muscari A, Bozzoli C, Puddu GM, et al.. Association of serum C3 levels with the risk of myocardial infarction. Am J Med. 1995; 98: 357–364.
5. Ridker PM, Cushman M, Stampfer MJ, et al.. Inflammation, aspirin, and the risk of cardiovascular disease in apparently healthy men. N Engl J Med. 1997; 336: 973–979.
6. Fazzini F, Peri G, Doni A, et al.. PTX3 in small-vessel vasculitides: an independent indicator of disease activity produced at sites of inflammation. Arthritis Rheum. 2001; 44: 2841–2850.
7. Peri G, Introna M, Corradi D, et al.. PTX3, A prototypical long pentraxin, is an early indicator of acute myocardial infarction in humans. Circulation. 2000; 102: 636–641.
8. Latini R, Maggioni AP, Peri G, et al.. Prognostic significance of the long pentraxin PTX3 in acute myocardial infarction. Circulation. 2004; 110: 2349–2354.
9. Muller B, Peri G, Doni A, et al.. Circulating levels of the long pentraxin PTX3 correlate with severity of infection in critically ill patients. Crit Care Med. 2001; 29: 1404–1407.
10. Bevelacqua V, Libra M, Mazzarino MC, et al.. Long pentraxin 3: a marker of inflammation in untreated psoriatic patients. Int J Mol Med. 2006; 18: 415–423.
11. Inoue K, Sugiyama A, Reid PC, et al.. Establishment of a high sensitivity plasma assay for human pentraxin3 as a marker for unstable angina pectoris. Arterioscler Thromb Vasc Biol. 2007; 27: 161–167.
12. Suzuki S, Takeishi Y, Niizeki T, et al.. Pentraxin 3, a new marker for vascular inflammation, predicts adverse clinical outcomes in patients with heart failure. Am Heart J. 2008; 155: 75–81.
13. Matsubara J, Sugiyama S, Nozaki T, et al.. Pentraxin 3 is a new inflammatory marker correlated with left ventricular diastolic dysfunction and heart failure with normal ejection fraction. J Am Coll Cardiol. 2011; 57: 861–869.
14. Dubin R, Li Y, Ix JH, et al.. Associations of pentraxin-3 with cardiovascular events, incident heart failure, and mortality among persons with coronary heart disease: data from the Heart and Soul Study. Am Heart J. 2012; 163: 274–279.
16. Soeki T, Niki T, Kusunose K, et al.. Elevated concentrations of pentraxin 3 are associated with coronary plaque vulnerability. J Cardiol. 2011; 58: 151–157.
17. SYNTAX working group. SYNTAX score calculator. Available at http://www.syntaxscore.com. Accessed May 20, 2012.
18. Gensini GG. A more meaningful scoring system for determining the severity of coronary heart disease. Am J Cardiol. 1983; 51: 606.
20. Mantovani A, Garlanda C, Bottazzi B, et al.. The long pentraxin PTX3 in vascular pathology. Vascul Pharmacol. 2006; 45: 326–330.
21. Matsui S, Ishii J, Kitagawa F, et al.. Pentraxin 3 in unstable angina and non-ST-segment elevation myocardial infarction. Atherosclerosis. 2010; 210: 220–225.
22. Jenny NS, Arnold AM, Kuller LH, et al.. Associations of pentraxin 3 with cardiovascular disease and all-cause death: the Cardiovascular Health Study. Arterioscler Thromb Vasc Biol. 2009; 29: 594–599.
26. Serruys PW, Morice MC, Kappetein AP, et al.. Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease. N Engl J Med. 2009; 360: 961–972.
27. van Gaal WJ, Ponnuthurai FA, Selvanayagam J, et al.. The SYNTAX score predicts peri-procedural myocardial necrosis during percutaneous coronary intervention. Int J Cardiol. 2009; 135: 60–65.
28. Lemesle G, Bonello L, de Labriolle A, et al.. Prognostic value of the SYNTAX score in patients undergoing coronary artery bypass grafting for three-vessel coronary artery disease. Catheter Cardiovasc Interv. 2009; 73: 612–617.
29. Capodanno D, Di Salvo ME, Cincotta G, et al.. Usefulness of the SYNTAX score for predicting clinical outcome after percutaneous coronary intervention of unprotected left main coronary artery disease. Circ Cardiovasc Interv. 2009; 2: 302–308.
30. Kim YH, Park DW, Kim WJ, et al.. Validation of SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score for prediction of outcomes after unprotected left main coronary revascularization. JACC Cardiovasc Interv. 2010; 3: 612–623.
32. Jaillon S, Peri G, Delneste Y, et al.. The humoral pattern recognition receptor PTX3 is stored in neutrophil granules and localizes in extracellular traps. J Exp Med. 2007; 204: 793–804.
33. Inforzato A, Baldock C, Jowitt TA, et al.. The angiogenic inhibitor long pentraxin PTX3 forms an asymmetric octamer with two binding sites for FGF2. J Biol Chem. 2010; 285: 17681–17692.
34. Camozzi M, Zacchigna S, Rusnati M, et al.. Pentraxin 3 inhibits fibroblast growth factor 2–dependent activation of smooth muscle cells in vitro and neointima formation in vivo. Arterioscler Thromb Vasc Biol. 2005; 25: 1837–1842.
35. Koenig W, Sund M, Frohlich M, et al.. C-Reactive protein, a sensitive marker of inflammation, predicts future risk of coronary heart disease in initially healthy middle-aged men: results from the MONICA (Monitoring Trends and Determinants in Cardiovascular Disease) Augsburg Cohort Study, 1984 to 1992. Circulation. 1999; 99: 237–242.
Keywords:  pentraxin 3; coronary artery disease; SYNTAX score; hs-CRP; inflammation

This is not the only recent finding that adds to the ability to evaluate these patients.  An as yet unpublished paper, expected to be published soon reports on

QRS fragmentation as a Prognostic test in Acute Coronary Syndrome,  and this reviewer expects the work to have a high impact.  The authors state that
QRS complex fragmentation is a promising bed-side test for assessment of prognosis in those patients.  Presence of fragmented QRS in surface ECG during ACS

  • represents myocardial scar or fibrosis and reflect severity of coronary lesions and a correlation between fQRS and depression of Lv function is established.

There are still other indicators that need to be considered, such as the mean arterial blood pressure.

There has been review and revisions of the guidelines for treatment of UA/NSTEMI within the last year, with differences being resolved among the Europeans and US.

Guidelines Updated for Unstable Angina/Non-ST Elevation Myocardial Infarction
According to the current study by Jneid and colleagues, new evidence is available on the management of unstable angina. This report replaces the 2007 American College of Cardiology Foundation/American Heart Association (ACC/AHA) Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction (UA/NSTEMI) that were updated by the 2011 guidelines.

This guideline was reviewed by

  • 2 official reviewers each nominated by the ACCF and the AHA, as well as
  • 1 or 2 reviewers each from the American College of Emergency Physicians; the Society for Cardiovascular Angiography and Interventions; and the Society of Thoracic Surgeons; and
  • 29 individual content reviewers, including members of the ACCF Interventional Scientific Council.

The recommendations in this focused update are considered current

  • until they are superseded in another focused update or the full-text guideline is revised, and are official policy of both the ACCF and the AHA.

STUDY SYNOPSIS AND PERSPECTIVE
American cardiology societies have caught up with the European Society of Cardiology by

  • issuing their second update to the UA/NSTEMI guidelines in 18 months,
  • with the 2012 focused update replacing the 2011 guidelines [1].

The new recommendations include ticagrelor (Brilinta) as one of the options for antiplatelet therapy alongside prasugrel (Effient) and clopidogrel, bringing them in line with European.
The European guidance, however, gave precedence to the new antiplatelets over clopidogrel, whereas the American update “places ticagrelor on an equal footing with the other two antiplatelets available–
this is the main reason for the update,” lead author Dr Hani Jneid (Baylor College of Medicine, Houston, TX), told heartwire . “Doctors now have a choice for second-line therapy after aspirin, depending on

  • the patient’s clinical scenario,
  • physician preference, and cost,”
    • now that clopidogrel is available generically.

The US decision to recommend

  • first prasugrel–in its 2011 update to the UA/NSTEMI guidelines–and
  • now ticagrelor as equivalent antiplatelet therapy choices to clopidogrel after aspirin
    • puts it somewhat at odds with the Europeans,
    • who reserve clopidogrel use for those who cannot take the newer agents.

The reason for the Americans differing stance is that because while they are faster acting and more potent–

  • the cost-effectiveness of the new agents is not known.
  • it isn’t clear how the efficacy observed in pivotal clinical trials of these agents is going to translate into real-world benefit,
  • and issues such as bleeding with prasugrel and compliance with a twice-daily drug such as ticagrelor remain concerns.

Bulk of 2012 Update on How to Use Ticagrelor
The 2012 ACCF/AHA focused update for the management of UA/NSTEMI stresses that

  • all patients at medium/high risk should receive dual antiplatelet therapy on admission,
  • with aspirin being first-line, indefinite therapy.

The bulk of the update centers on how to use ticagrelor which–

  • like prasugrel or clopidogrel–
  • can be added to aspirin for up to 12 months (or longer, at the discretion of the treating clinician).

Jneid notes it’s important to remember that prasugrel can only be used in the cath lab

  • in patients undergoing percutaneous coronary intervention (PCI),
  • whereas ticagrelor, like clopidogrel, can be used in medically managed or PCI patients.

And he emphasizes that, in line with the FDA’s black-box warning on ticagrelor,

The 81-mg aspirin dose is also considered a reasonable option in preference to a higher maintenance dose of 325 mg in

  • any acute coronary syndrome (ACS) patient following PCI, he adds, as
  • this strategy is believed to result in equal efficacy and lower bleeding risk.

With regard to how long antiplatelet therapy should be stopped before planned cardiac surgery, the recommendation is

  • five days for ticagrelor–the same as that advised for clopidogrel.
  • and seven days prior to surgery for prasugrel.

Jneid also highlights other important recommendations from the 2011 focused update carried over to 2012:

It is “reasonable” to proceed with cardiac catheterization and revascularization within

  • 12–24 hours of admission in initially stable, very high-risk patients with ACS.

An invasive strategy is “reasonable” in patients with

  • mild and moderate chronic kidney disease.

In those with diabetes hospitalized with ACS, insulin use should target glucose levels <180 mg/dL,

  • a less-intensive reduction than previously recommended.

Platelet function or genotype testing for clopidogrel resistance are both considered “reasonable”

  • if clinicians think the results will alter management,
  • but Jneid acknowledged that “there is not much evidence to support these assays” .

Committee Encourages Participation in Registries
Jneid observes that unstable angina and NSTEMI are “very common” conditions that carry a high risk of death and recurrent heart attacks,

  • which is why “the AHA and ACCF constantly update their guidelines so that physicians can provide patients with
  • the most appropriate, aggressive therapy with the goal of improving health and survival.”

To this end, he notes that the writing panel encourages

  • clinicians and hospitals to participate in quality-of-care registries designed
  • to track and measure outcomes, complications, and
  • adherence to evidence-based medicines.

Conflicts of interest for the writing committee are listed in the paper.

References

Jneid H, Anderson JL, Wright SR, et al. 2012 ACCF/AHA focused update on the guideline for the management of patients with unstable angina/non-ST elevation myocardial infarction (Updating the 2007 guideline and replacing the 2011 focused update): A report of the ACCF/AHA.
Circulation 2012;      Available at: http://circ.ahajournals.org/  http://dx.doi.org/10.1161/CIR0b013e3182566fleo
source   http://www.medscape.org

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Genomics & Genetics of Cardiovascular Disease Diagnoses: A Literature Survey of AHA’s Circulation Cardiovascular Genetics, 3/2010 – 3/2013

Posted in Atherogenic Processes & Pathology, Biological Networks, Gene Regulation and Evolution, Biomarkers & Medical Diagnostics, Cardiovascular Pharmacogenomics, Chemical Genetics, Computational Biology/Systems and Bioinformatics, Disease Biology, Small Molecules in Development of Therapeutic Drugs, FDA Regulatory Affairs, Frontiers in Cardiology and Cardiovascular Disorders, Genome Biology, Genomic Testing: Methodology for Diagnosis, HTN, Liver & Digestive Diseases Research, Metabolomics, Molecular Genetics & Pharmaceutical, Origins of Cardiovascular Disease, Personalized and Precision Medicine & Genomic Research, Pharmaceutical Analytics, Pharmacogenomics, Population Health Management, Genetics & Pharmaceutical, Proteomics, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Statistical Methods for Research Evaluation, Systemic Inflammatory Response Related Disorders, Technology Transfer: Biotech and Pharmaceutical, tagged , , , , , , , , , , , on March 7, 2013| 25 Comments »

Genomics & Genetics of Cardiovascular Disease Diagnoses: A Literature Survey of AHA’s Circulation Cardiovascular Genetics, 3/2010 – 3/2013

 

Curators: Aviva Lev-Ari, PhD, RN and Larry H. Bernstein, MD, FCAP

 

348 articles that appeared in AHA’s Circulation Cardiovascular Genetics, 3/2010 – 3/2013 were classified by the curators of this article into the following TEN categories. The first 9, represent DIAGNOSES of cardiovascular diseases, the last, deals with Pharmacogenomics.

The Cardiovascular Diagnoses that were covered in the period of 3/2010 – 3/2013, include the following:

  • Preventative Cardiology
  • MicroRNA in Serum as Bimarker for Cardiovascular Pathologies: acute myocardial infarction, viral myocarditis, diastolic dysfunction, and acute heart failure
  • Genetic Determinants of Potassium Sensitivity and Hypertension
  • Heart and Aging Research in Genomic Epidemiology: 1700 MIs and 2300 coronary heart disease events among about 29 000 eligible patients
  • Genetics of CVD and Hyperlipidemia, Hyper Cholesterolemia, Metabolic Syndrome
  • Genomics and Valvular Disease
  • Pharmacogenomics

Introductions

Larry H. Bernstein, MD, FCAP

 

The curation of this large amount of material in 10 categories begins with a first chapter on preventative cardiology, which has had much public attention for the last decade.  Much of the concern with preventive cardiology has emphasized diet and exercise.  There is much to be said about this in articles not yet written.  However, there are several decades of research on the amino acid composition of foods, and the essential fatty acids, that indicates an essential balance between proinflammatory and antiinflammatory fatty acids in polyunsaturated fatty acids, and of the harmful effects of saturated fats.  There is also much to be said of essential amino acids, and in particular, those essential for methylation processes, and sulfur metabolism.

The next eight chapters are all concerned with genomics in cardiovascular disease.  This is in no small part a follow up on the completion of the genetic code in 2003, a seminal event.  Let us look at these in clusters.

[1]   microRNA in serum is now considered for a biomarker for cardiovascular disease.  It can be measured at very low levels, but we don’t yet know where it fits.   It might be more revealing once we understand the adaptive mechanism in development of congestive heart failure, renal hypertension, and post-genomic events.

[2]  It appears to me that potassium sensitivity and hypertension approached from the genomic side is more complicate.  Why is that?   The kidney excretes a sodium load and in metabolic acidosis, the serum potassium rises with a metabolic acidemia that can’t be compensated by the respiratory loss of CO2 through the carbonic anhydrase mechanism.

[3]  Heart and aging research is a rich area for work on the long term post-genomic changes, and it involves a large population base.

[4][5]  The genomics of cardiac dysrrhytmias and cardiomyopathies will open new doors into our understanding of the mechanisms of these diseases, and perhaps find therapeutic targets.  There has been a large volume of work on lipid synthesis, the role of the liver in generating apolipoproteins, and this has new answers on the way.  The most important feature, not readily accepted is the measurement of particles, which has now been done by a monoclonal antibody.  Metabolic syndrome brings together adipose tissue metabolism, endocrine and changes in CRP and IL-1.

[6]   Vascular pathologies and coagulation, hyperviscosity has had an enormous increase in intensity of research.  The concept of plaque rupture to account for all AMIs is being modified, and the high sensitivity cardio-specific troponins have become the most widely use test.

[7]  The genomics of valvular disease fits with the increased surgical procedures for valvular disease related to atheroschlerosis and advent of minimally invasive surgical procedures for the reapir and replacement of valves, procedure called TAVR vs. Openhealrt surgery for valve replacement.

[8]  Inherited cardiovascular disease is an older family of disorders, going back to Victor McKusik, and also the “Blue Baby” operation, both at Johns Hopkins.

[9] Pharmacogenomics is a vary active field of investigation and has uncovered inter-individual differences in handling Warfarin as a starter.

 

 

Preventative Cardiology

 

Methods in Genetics and Clinical Interpretation Randomized Trial of Personal Genomics for Preventive Cardiology Design and Challenges

Joshua W. Knowles, MD, PhD, Themistocles L. Assimes, MD, PhD, Michaela Kiernan, PhD, Aleksandra Pavlovic, BS, Benjamin A. Goldstein, PhD, Veronica Yank, MD, Michael V. McConnell, MD, Devin Absher, PhD, Carlos Bustamante, PhD, Euan A. Ashley, MD, DPhil and John P.A. Ioannidis, MD, DSc

Author Affiliations

From the Division of Cardiovascular Medicine (J.W.K., T.L.A., A.P., M.V.M., E.A.A.), Stanford Prevention Research Center (M.K., V.Y., J.P.A.I.), Division of General Medical Disciplines (V.Y.), Department of Genetics (C.B.), Department of Health Research and Policy (J.P.A.I.), Stanford University School of Medicine, Stanford, CA; Quantitative Sciences Unit, Stanford University School of Medicine, Palo Alto, CA (B.A.G.); HudsonAlpha Institute for Biotechnology, Huntsville, AL (D.A.); Department of Statistics, Stanford University School of Humanities and Sciences, Stanford, CA (J.P.A.I.).

Correspondence to Joshua W. Knowles, MD, PhD, Stanford University School of Medicine, Division of Cardiovascular Medicine, Falk CVRC, 300 Pasteur Dr, Stanford, CA 94305. E-mail knowlej@stanford.edu

Background

Genome-wide association studies (GWAS) have identified more than 1500 disease-associated single nucleotide polymorphisms (SNPs), including many related to atherosclerotic cardiovascular disease (CVD). Associations have been found for most traditional risk factors (TRFs), including lipids,1,2 blood pressure/hypertension,3,4 weight/body mass index,5,6 smoking behavior,7 and diabetes.8–13 GWAS have also identified susceptibility variants for coronary heart disease (CHD). The first and, so far, strongest of these signals was found in the 9p21.3 locus, where common variants in this region increase the relative risk of CVD by 15% to 30% per risk allele in most race/ethnic groups.13–20 Subsequent large-scale GWAS meta-analyses and replication studies in largely white/European populations have led to the reliable identification of an additional 26 loci conferring susceptibility to CHD,2,20–23 all with substantially lower effects sizes compared with the 9p21 locus. Many of these CVD susceptibility loci appear to be conferring risk independent of TRFs and thus cannot currently be assessed by surrogate clinical measures (Table 1). Among the 27 independent loci identified in the most recent large meta-analyses of CVD, 21 were reported not to be associated with any of the TRFs.20,21

 SOURCE

Circulation: Cardiovascular Genetics 2012; 5: 368-376

doi: 10.1161/ CIRCGENETICS.112.962746

 

 

MicroRNA in Serum as Bimarker for Cardiovascular Pathologies: acute myocardial infarction, viral myocarditis,  diastolic dysfunction, and acute heart failure

Increased MicroRNA-1 and MicroRNA-133a Levels in Serum of Patients With Cardiovascular Disease Indicate Myocardial Damage

 

Yasuhide Kuwabara, MD, Koh Ono, MD, PhD, Takahiro Horie, MD, PhD, Hitoo Nishi, MD, PhD, Kazuya Nagao, MD, PhD, Minako Kinoshita, MD, PhD, Shin Watanabe, MD, PhD, Osamu Baba, MD, Yoji Kojima, MD, PhD, Satoshi Shizuta, MD, Masao Imai, MD, Toshihiro Tamura, MD, Toru Kita, MD, PhD and Takeshi Kimura, MD, PhD

Author Affiliations

From the Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Y. Kuwabara, K.O., T.H., H.N., K.N., M.K., S.W., O.B., Y. Kojima, S.S., M.I., T.T., T. Kimura); and Kobe City Medical Center General Hospital, Kobe, Japan (T. Kita).

Correspondence to Koh Ono, MD, PhD, Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto, Japan 606-8507. E-mail kohono@kuhp.kyoto-u.ac.jp

 

Abstract

Background—Recently, elevation of circulating muscle-specific microRNA (miRNA) levels has been reported in patients with acute myocardial infarction. However, it is still unclear from which part of the myocardium or under what conditions miRNAs are released into circulating blood. The purpose of this study was to identify the source of elevated levels of circulating miRNAs and their function in cardiovascular diseases.

Conclusions—These results suggest that elevated levels of circulating miR-133a in patients with cardiovascular diseases originate mainly from the injured myocardium. Circulating miR-133a can be used as a marker for cardiomyocyte death, and it may have functions in cardiovascular diseases.

SOURCE:

Circulation: Cardiovascular Genetics. 2011; 4: 446-454

Published online before print June 2, 2011,

doi: 10.1161/ CIRCGENETICS.110.958975

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Circulating MicroRNA-208b and MicroRNA-499 Reflect Myocardial Damage in Cardiovascular Disease

Maarten F. Corsten, MD, Robert Dennert, MD, Sylvia Jochems, BSc, Tatiana Kuznetsova, MD, PhD, Yvan Devaux, PhD, Leon Hofstra, MD, PhD, Daniel R. Wagner, MD, PhD, Jan A. Staessen, MD, PhD, Stephane Heymans, MD, PhD and Blanche Schroen, PhD

Author Affiliations

From the Center for Heart Failure Research (M.F.C., R.D., S.J., S.H., B.S.), Cardiovascular Research Institute, Maastricht, The Netherlands; the Division of Hypertension and Cardiovascular Rehabilitation (T.K., J.A.S.), Department of Cardiovascular Diseases, University of Leuven, Leuven, Belgium and Department of Epidemiology, Maastricht University Medical Center, Maastricht, The Netherlands; Centre de Recherche Public–Santé, Luxembourg (Y.D., D.R.W.), Luxembourg; Maastricht University Medical Center (L.H.), Maastricht, The Netherlands; and Centre Hospitalier Luxembourg (D.R.W.), Luxembourg.

Correspondence to Blanche Schroen, PhD, Center for Heart Failure Research, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands. E-mail b.schroen@cardio.unimaas.nl

Drs Heymans and Schroen contributed equally to this work.

Abstract

Background— Small RNA molecules, called microRNAs, freely circulate in human plasma and correlate with varying pathologies. In this study, we explored their diagnostic potential in a selection of prevalent cardiovascular disorders.

Methods and Results— MicroRNAs were isolated from plasmas from well-characterized patients with varying degrees of cardiac damage:

(1) acute myocardial infarction,

(2) viral myocarditis,

(3) diastolic dysfunction, and

(4) acute heart failure.

Plasma levels of selected microRNAs, including heart-associated (miR-1, -133a, -208b, and -499), fibrosis-associated (miR-21 and miR-29b), and leukocyte-associated (miR-146, -155, and -223) candidates, were subsequently assessed using real-time polymerase chain reaction. Strikingly, in plasma from acute myocardial infarction patients, cardiac myocyte–associated miR-208b and -499 were highly elevated, 1600-fold (P<0.005) and 100-fold (P<0.0005), respectively, as compared with control subjects. Receiver operating characteristic curve analysis revealed an area under the curve of 0.94 (P<10−10) for miR-208b and 0.92 (P<10−9) for miR-499. Both microRNAs correlated with plasma troponin T, indicating release of microRNAs from injured cardiomyocytes. In viral myocarditis, we observed a milder but significant elevation of these microRNAs, 30-fold and 6-fold, respectively. Plasma levels of leukocyte-expressed microRNAs were not significantly increased in acute myocardial infarction or viral myocarditis patients, despite elevated white blood cell counts. In patients with acute heart failure, only miR-499 was significantly elevated (2-fold), whereas no significant changes in microRNAs studied could be observed in diastolic dysfunction. Remarkably, plasma microRNA levels were not affected by a wide range of clinical confounders, including age, sex, body mass index, kidney function, systolic blood pressure, and white blood cell count.

Conclusions— Cardiac damage initiates the detectable release of cardiomyocyte-specific microRNAs-208b and -499 into the circulation.

SOURCE:

Circulation: Cardiovascular Genetics. 2010; 3: 499-506

Published online before print October 4, 2010,

doi: 10.1161/ CIRCGENETICS.110.957415

 

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Genetic Determinants of Potassium Sensitivity and Hypertension

 

Integrated Computational and Experimental Analysis of the Neuroendocrine Transcriptome in Genetic Hypertension Identifies Novel Control Points for the Cardiometabolic Syndrome

Ryan S. Friese, PhD, Chun Ye, PhD, Caroline M. Nievergelt, PhD, Andrew J. Schork, BS, Nitish R. Mahapatra, PhD, Fangwen Rao, MD, Philip S. Napolitan, BS, Jill Waalen, MD, MPH, Georg B. Ehret, MD, Patricia B. Munroe, PhD, Geert W. Schmid-Schönbein, PhD, Eleazar Eskin, PhD and Daniel T. O’Connor, MD

Author Affiliations

From the Departments of Bioengineering (R.S.F., G.W.S.-S.), Medicine (R.S.F., A.J.S., F.R., P.S.N., D.T.O.), Pharmacology (D.T.O.), and Psychiatry (C.M.N.), the Bioinformatics Program (C.Y.), and the Institute for Genomic Medicine (D.T.O.), University of California at San Diego; the VA San Diego Healthcare System, San Diego, CA (D.T.O.); the Departments of Computer Science & Human Genetics, University of California at Los Angeles (E.E.); the Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India (N.R.M.); Clinical Pharmacology and The Genome Centre, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom (P.B.M.); Center for Complex Disease Genomics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (G.B.E.); and Scripps Research Institute, La Jolla, CA (J.W.).

Correspondence to Daniel T. O’Connor, MD, Department of Medicine, University of California at San Diego School of Medicine, VASDHS (0838), Skaggs (SSPPS) Room 4256, 9500 Gilman Drive, La Jolla, CA 92093-0838. E-mail doconnor@ucsd.edu

Abstract

Background—Essential hypertension, a common complex disease, displays substantial genetic influence. Contemporary methods to dissect the genetic basis of complex diseases such as the genomewide association study are powerful, yet a large gap exists betweens the fraction of population trait variance explained by such associations and total disease heritability.

Methods and Results—We developed a novel, integrative method (combining animal models, transcriptomics, bioinformatics, molecular biology, and trait-extreme phenotypes) to identify candidate genes for essential hypertension and the metabolic syndrome. We first undertook transcriptome profiling on adrenal glands from blood pressure extreme mouse strains: the hypertensive BPH (blood pressure high) and hypotensive BPL (blood pressure low). Microarray data clustering revealed a striking pattern of global underexpression of intermediary metabolism transcripts in BPH. The MITRA algorithm identified a conserved motif in the transcriptional regulatory regions of the underexpressed metabolic genes, and we then hypothesized that regulation through this motif contributed to the global underexpression. Luciferase reporter assays demonstrated transcriptional activity of the motif through transcription factors HOXA3, SRY, and YY1. We finally hypothesized that genetic variation at HOXA3, SRY, and YY1 might predict blood pressure and other metabolic syndrome traits in humans. Tagging variants for each locus were associated with blood pressure in a human population blood pressure extreme sample with the most extensive associations for YY1 tagging single nucleotide polymorphism rs11625658 on systolic blood pressure, diastolic blood pressure, body mass index, and fasting glucose. Meta-analysis extended the YY1 results into 2 additional large population samples with significant effects preserved on diastolic blood pressure, body mass index, and fasting glucose.

Conclusions—The results outline an innovative, systematic approach to the genetic pathogenesis of complex cardiovascular disease traits and point to transcription factor YY1 as a potential candidate gene involved in essential hypertension and the cardiometabolic syndrome.

 SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 430-440

Published online before print June 5, 2012,

doi: 10.1161/ CIRCGENETICS.111.962415

Genome-Wide Linkage and Positional Candidate Gene Study of Blood Pressure Response to Dietary Potassium Intervention

The Genetic Epidemiology Network of Salt Sensitivity Study

Tanika N. Kelly, PhD, James E. Hixson, PhD, Dabeeru C. Rao, PhD, Hao Mei, MD, PhD, Treva K. Rice, PhD, Cashell E. Jaquish, PhD, Lawrence C. Shimmin, PhD, Karen Schwander, MS, Chung-Shuian Chen, MS, Depei Liu, PhD, Jichun Chen, MD, Concetta Bormans, PhD, Pramila Shukla, MS, Naveed Farhana, MS, Colin Stuart, BS, Paul K. Whelton, MD, MSc, Jiang He, MD, PhD and Dongfeng Gu, MD, PhD

Author Affiliations

From the Department of Epidemiology (T.N.K., H.M., C.-S.C., J.H.), Tulane University School of Public Health and Tropical Medicine, and Department of Medicine (J.H.), Tulane University School of Medicine, New Orleans, La; Department of Epidemiology (J.E.H., L.C.S., C.B., P.S., N.F., C.S.), University of Texas School of Public Health, Houston, Tex; Division of Biostatistics (D.C.R., T.K.R., K.S.), Washington University School of Medicine, St Louis, Mo; Division of Prevention and Population Sciences (C.E.J.), National Heart, Lung, Blood Institute, Bethesda, Md; National Laboratory of Medical Molecular Biology (D.L.), Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; Cardiovascular Institute and Fuwai Hospital (J.C., D.G.), Chinese Academy of Medical Sciences and Peking Union Medical College and Chinese National Center for Cardiovascular Disease Control and Research, Beijing, China; and Office of the President (P.K.W.), Loyola University Health System and Medical Center, Maywood, Ill.

Correspondence to Dongfeng Gu, MD, PhD, Division of Population Genetics and Prevention, Cardiovascular Institute and Fuwai Hospital, 167 Beilishi Rd, Beijing 100037, China. E-mail gudongfeng@vip.sina.com

Abstract

Background— Genetic determinants of blood pressure (BP) response to potassium, or potassium sensitivity, are largely unknown. We conducted a genome-wide linkage scan and positional candidate gene analysis to identify genetic determinants of potassium sensitivity.

Conclusions— Genetic regions on chromosomes 3 and 11 may harbor important susceptibility loci for potassium sensitivity. Furthermore, the AGTR1 gene was a significant predictor of BP responses to potassium intake.

SOURCE:

Circulation: Cardiovascular Genetics. 2010; 3: 539-547

Published online before print September 22, 2010,

doi: 10.1161/ CIRCGENETICS.110.940635

 

Genome-Wide Association Study of Cardiac Structure and Systolic Function in African Americans

The Candidate Gene Association Resource (CARe) Study

Ervin R. Fox, MD*, Solomon K. Musani, PhD*, Maja Barbalic, PhD*, Honghuang Lin, PhD, Bing Yu, MS, Kofo O. Ogunyankin, MD, Nicholas L. Smith, PhD, Abdullah Kutlar, MD, Nicole L. Glazer, MD, Wendy S. Post, MD, MS, Dina N. Paltoo, PhD, MPH, Daniel L. Dries, MD, MPH, Deborah N. Farlow, PhD, Christine W. Duarte, PhD, Sharon L. Kardia, PhD, Kristin J. Meyers, PhD, Yan V. Sun, PhD, Donna K. Arnett, PhD, Amit A. Patki, MS, Jin Sha, MS, Xiangqui Cui, PhD, Tandaw E. Samdarshi, MD, MPH, Alan D. Penman, PhD, Kirsten Bibbins-Domingo, MD, PhD, Petra Bůžková, PhD, Emelia J. Benjamin, MD, David A. Bluemke, MD, PhD, Alanna C. Morrison, PhD, Gerardo Heiss, MD, J. Jeffrey Carr, MD, MSc, Russell P. Tracy, PhD, Thomas H. Mosley, PhD, Herman A. Taylor, MD, Bruce M. Psaty, MD, PhD, Susan R. Heckbert, MD, PhD, Thomas P. Cappola, MD, ScM and Ramachandran S. Vasan, MD

Author Affiliations

Guest Editor for this article was Barry London, MD, PhD.

Correspondence to Ervin Fox, MD MPH, FAHA, FACC, Professor of Medicine, Department of Medicine, University of Mississippi Medical Center, 2500 North State St, Jackson, MS 39216. E-mail efox@medicine.umsmed.edu

↵* These authors contributed equally as joint first authors.

Abstract

Background—Using data from 4 community-based cohorts of African Americans, we tested the association between genome-wide markers (single-nucleotide polymorphisms) and cardiac phenotypes in the Candidate-gene Association Resource study.

Methods and Results—Among 6765 African Americans, we related age, sex, height, and weight-adjusted residuals for 9 cardiac phenotypes (assessed by echocardiogram or magnetic resonance imaging) to 2.5 million single-nucleotide polymorphisms genotyped using Genome-wide Affymetrix Human SNP Array 6.0 (Affy6.0) and the remainder imputed. Within the cohort, genome-wide association analysis was conducted, followed by meta-analysis across cohorts using inverse variance weights (genome-wide significance threshold=4.0 ×10−7). Supplementary pathway analysis was performed. We attempted replication in 3 smaller cohorts of African ancestry and tested lookups in 1 consortium of European ancestry (EchoGEN). Across the 9 phenotypes, variants in 4 genetic loci reached genome-wide significance: rs4552931 in UBE2V2 (P=1.43×10−7) for left ventricular mass, rs7213314 in WIPI1 (P=1.68×10−7) for left ventricular internal diastolic diameter, rs1571099 in PPAPDC1A (P=2.57×10−8) for interventricular septal wall thickness, and rs9530176 in KLF5 (P=4.02×10−7) for ejection fraction. Associated variants were enriched in 3 signaling pathways involved in cardiac remodeling. None of the 4 loci replicated in cohorts of African ancestry was confirmed in lookups in EchoGEN.

Conclusions—In the largest genome-wide association study of cardiac structure and function to date in African Americans, we identified 4 genetic loci related to left ventricular mass, interventricular septal wall thickness, left ventricular internal diastolic diameter, and ejection fraction, which reached genome-wide significance. Replication results suggest that these loci may be unique to individuals of African ancestry. Additional large-scale studies are warranted for these complex phenotypes.

SOURCE:

Circulation: Cardiovascular Genetics. 2013; 6: 37-46

Published online before print December 28, 2012,

doi: 10.1161/ CIRCGENETICS.111.962365

 

Heart and Aging Research in Genomic Epidemiology: 1700 MIs and 2300 coronary heart disease events among about 29 000 eligible patients

 

Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium

Design of Prospective Meta-Analyses of Genome-Wide Association Studies From 5 Cohorts

Bruce M. Psaty, MD, PhD, Christopher J. O’Donnell, MD, MPH, Vilmundur Gudnason, MD, PhD, Kathryn L. Lunetta, PhD, Aaron R. Folsom, MD, Jerome I. Rotter, MD, André G. Uitterlinden, PhD, Tamara B. Harris, MD, Jacqueline C.M. Witteman, PhD, Eric Boerwinkle, PhD and on Behalf of the CHARGE Consortium

Author Affiliations

From the Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Services (B.M.P.), University of Wash; Center for Health Studies, Group Health (B.M.P.), Seattle, Wash; the National Heart, Lung and Blood Institute and the Framingham Heart Study (C.J.O.D.), Framingham, Mass; Icelandic Heart Association and the Department of Cardiovascular Genetics (Y.G.), University of Iceland, Reykjavik, Iceland; Department of Biostatistics (K.L.), Boston University School of Public Health, Mass; Division of Epidemiology and Community Health (A.R.F.), University of Minnesota, Minneapolis; Medical Genetics Institute (J.I.R.), Cedars-Sinai Medical Center, Los Angeles, Calif; Departments of Internal Medicine (A.G.U.) and Epidemiology (A.G.U., J.C.M.W.), Erasmus Medical Center, Rotterdam, The Netherlands; Laboratory of Epidemiology, Demography, and Biometry (T.B.H.), Intramural Research Program, National Institute on Aging, Bethesda, Md; and Human Genetics Center and Division of Epidemiology (E.B.), University of Texas, Houston.

Guest editor for this article was Elizabeth R. Hauser, PhD.

Abstract

Background— The primary aim of genome-wide association studies is to identify novel genetic loci associated with interindividual variation in the levels of risk factors, the degree of subclinical disease, or the risk of clinical disease. The requirement for large sample sizes and the importance of replication have served as powerful incentives for scientific collaboration.

Methods— The Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium was formed to facilitate genome-wide association studies meta-analyses and replication opportunities among multiple large population-based cohort studies, which collect data in a standardized fashion and represent the preferred method for estimating disease incidence. The design of the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium includes 5 prospective cohort studies from the United States and Europe: the Age, Gene/Environment Susceptibility—Reykjavik Study, the Atherosclerosis Risk in Communities Study, the Cardiovascular Health Study, the Framingham Heart Study, and the Rotterdam Study. With genome-wide data on a total of about 38 000 individuals, these cohort studies have a large number of health-related phenotypes measured in similar ways. For each harmonized trait, within-cohort genome-wide association study analyses are combined by meta-analysis. A prospective meta-analysis of data from all 5 cohorts, with a properly selected level of genome-wide statistical significance, is a powerful approach to finding genuine phenotypic associations with novel genetic loci.

Conclusions— The Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium and collaborating non-member studies or consortia provide an excellent framework for the identification of the genetic determinants of risk factors, subclinical-disease measures, and clinical events.

Example of Coronary Heart Disease

The cohort-study methods papers provide detail about many of the phenotypes listed in Table 2. For coronary heart disease, investigators knowledgeable about the phenotype in each study decided to focus on fatal and nonfatal myocardial infarction (MI) as the primary outcome because the MI criteria differed in only trivial ways among the studies. There were some minor differences in the definition of the composite outcome of MI, fatal coronary heart disease, and sudden death, which became the secondary outcome. Only subjects at risk for an incident event were included in the analysis. MI survivors whose DNA was drawn after the event were not eligible. The primary analysis was restricted to Europeans or European Americans. Patients entered the analysis at the time of the DNA blood draw, and were followed until an event, death, loss to follow up, or the last visit. The main recommendations of the Analysis Committee were adopted, and a threshold of 5×10−8 was selected for genome-wide statistical significance. Analyses in progress include about 1700 MIs and 2300 coronary heart disease events among about 29 000 eligible patients. Each cohort conducted its own analysis, and results were uploaded to a secure share site for the fixed-effects meta-analysis. Even with this number of events (Supplemental Figure 2), power is good for only for relatively high minor allele frequencies (>0.25) and large relative risks (>1.3).

The authors had full access to and take full responsibility for the integrity of the data. All authors have read and agree to the manuscript as written.

Discussion

In thousands of published papers, the 5 CHARGE cohort studies and many of the collaborating studies have already characterized the risk factors for and the incidence and prognosis of a variety of aging-related and cardiovascular conditions. The analysis of the incident MI, for instance, is free from the survival bias typically associated with cross-sectional or case-control studies. The methodologic advantages of the prospective population-based cohort design, the similarity of phenotypes across 5 studies, the availability of genome-wide genotyping data in each cohort, and the need for large sample sizes to provide reliable estimates of genotype-phenotype associations have served as the primary incentives for the formation of the CHARGE consortium, which includes GWAS data on about 38 000 individuals. The consortium effort relies on collaborative methods that are similar to those used by the individual contributing cohorts.

Phenotype experts who know the studies and the data well are responsible for phenotype-standardization across cohorts. The coordinated prospectively planned meta-analyses of CHARGE provide results that are virtually identical to a cohort-adjusted pooled analysis of individual level data. This approach–the within-study analysis followed by a between-study meta-analysis–avoids the human subjects issues associated with individual-level data sharing.

Editors, reviewers, and readers expect replication as the standard in science.6 The finding of a genetic association in one population with evidence for replication in multiple independent populations provides moderate assurance against false-positive reports and helps to establish the validity of the original finding. In a single experiment, the discovery-replication structure is traditionally embodied in a 2-stage design. The CHARGE consortium includes up to 5 independent replicate samples as well as additional collaborating studies for some phenotype working groups, so that it would have been possible to set up analysis plans within CHARGE to mimic the traditional 2-stage design for replication. For instance, the 2 largest cohorts could have served as the discovery set and the others as the replication set. However, attaining the extremely small probability values expected in GWAS requires large sample sizes. For any phenotype, a prospective meta-analysis of all participating cohorts, with a properly selected level of genome-wide statistical significance to minimize the chance of false-positives, is the most powerful approach to finding new genuine associations for genetic loci.25 When findings narrowly miss the prespecified significance threshold, genotyping individuals in other independent populations provides additional evidence about the association. For findings that substantially exceed pre-established significance thresholds, the results of a CHARGE meta-analysis effectively provide evidence of a multistudy replication.

The effort to assemble and manage the CHARGE consortium has provided some interesting and unanticipated challenges. Participating cohorts often had relationships with outside study groups that predated the formation of CHARGE. Timelines for genotyping and imputation have shifted. Purchases of new computer systems for the volume of work were sometimes necessary. Each cohort came to the consortium with their own traditions for methods of analysis, organization, and authorship policies that, while appropriate for their own work, were not always optimal for collaboration with multiple external groups. Within each cohort, the investigators had often formed working groups that divided up the large number of available phenotypes in ways that made sense locally but did not necessarily match the configuration that had been adopted by other cohorts. The Research Steering Committee has attempted to create a set of CHARGE working groups that accommodate the needs and the conventions of the various cohorts. Transparency, disclosure, and professional collaborative behavior by all participating investigators have been essential to the process.

Resource limitations are another challenge. Grant applications that funded the original single-study genome-wide genotyping effort typically imagined a much simpler design. The CHS whole-genome study had as its primary aim, for instance, the analysis of data on 3 endpoints, coronary disease, stroke and heart failure. With a score of active phenotype working groups, the CHARGE collaboration broadened the scope of the short-term work well beyond initial expectations for all the participating cohorts.

One of the premier challenges has been communications among scores of investigators at a dozen sites. CHS and ARIC are themselves multi-site studies. To be successful, the CHARGE collaboration has required effective communications: (1) within each cohort; (2) between cohorts; (3) within the CHARGE working groups; and (4) among the major CHARGE committees. In addition to the traditional methods of conference calls and email, the CHARGE “wiki,” set up by Dr J. Bis (Seattle, Wash), has provided a crucial and highly functional user-driven website for calendars, minutes, guidelines, working group analysis plans, manuscript proposals, and other documents. In the end, there is no substitute for face-to-face meetings, especially at the beginning of the collaboration, and this complex meta-organization has benefited from several CHARGE-wide meetings.

The major emerging opportunity is the collaboration with other studies and consortia. Many working groups have already incorporated nonmember studies into their efforts. Several working groups have coordinated submissions of initial manuscripts with the parallel submission of manuscripts from other studies or consortia. Several working groups have embarked on plans for joint meta-analyses between CHARGE and other consortia. CHARGE has tried to acknowledge and reward the efforts of champions, who assume leadership responsibility for moving these large complex projects forward and who are often hard-working young investigators, the key to the future success of population science.

The CHARGE Consortium represents an innovative model of collaborative research conducted by research teams that know well the strengths, the limitations, and the data from 5 prospective population-based cohort studies. By leveraging the dense genotyping, deep phenotyping and the diverse expertise, prospective meta-analyses are underway to identify and replicate the major common genetic determinants of risk factors, measures of subclinical disease, and clinical events for cardiovascular disease and aging.

SOURCE:

Circulation: Cardiovascular Genetics.2009; 2: 73-80

doi: 10.1161/ CIRCGENETICS.108.829747

 

 

Genomics of Ventricular arrhythmias, A-Fib, Right Ventricular Dysplasia, Cardiomyopathy

 

Comprehensive Desmosome Mutation Analysis in North Americans With Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

A. Dénise den Haan, MD, Boon Yew Tan, MBChB, Michelle N. Zikusoka, MD, Laura Ibañez Lladó, MS, Rahul Jain, MD, Amy Daly, MS, Crystal Tichnell, MGC, Cynthia James, PhD, Nuria Amat-Alarcon, MS, Theodore Abraham, MD, Stuart D. Russell, MD, David A. Bluemke, MD, PhD, Hugh Calkins, MD, Darshan Dalal, MD, PhD and Daniel P. Judge, MD

Author Affiliations

From the Department of Medicine/Cardiology (A.D.d.H., B.Y.T., M.N.Z., L.I.L., R.J., A.D., C.T., C.J., N.A.-A., T.A., S.D.R., H.C., D.D., D.P.J.), Johns Hopkins University School of Medicine, Baltimore, Md; Department of Cardiology, Division of Heart and Lungs (A.D.d.H.), University Medical Center Utrecht, Utrecht, The Netherlands; and National Institutes of Health, Radiology and Imaging Sciences (D.A.B.), Bethesda, Md.

Correspondence to Daniel P. Judge, MD, Johns Hopkins University, Division of Cardiology, Ross 1049; 720 Rutland Avenue, Baltimore, MD 21205. E-mail djudge@jhmi.edu

Abstract

Background— Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited disorder typically caused by mutations in components of the cardiac desmosome. The prevalence and significance of desmosome mutations among patients with ARVD/C in North America have not been described previously. We report comprehensive desmosome genetic analysis for 100 North Americans with clinically confirmed or suspected ARVD/C.

Methods and Results— In 82 individuals with ARVD/C and 18 people with suspected ARVD/C, DNA sequence analysis was performed on PKP2, DSG2, DSP, DSC2, and JUP. In those with ARVD/C, 52% harbored a desmosome mutation. A majority of these mutations occurred in PKP2. Notably, 3 of the individuals studied have a mutation in more than 1 gene. Patients with a desmosome mutation were more likely to have experienced ventricular tachycardia (73% versus 44%), and they presented at a younger age (33 versus 41 years) compared with those without a desmosome mutation. Men with ARVD/C were more likely than women to carry a desmosome mutation (63% versus 38%). A mutation was identified in 5 of 18 patients (28%) with suspected ARVD. In this smaller subgroup, there were no significant phenotypic differences identified between individuals with a desmosome mutation compared with those without a mutation.

Conclusions— Our study shows that in 52% of North Americans with ARVD/C a mutation in one of the cardiac desmosome genes can be identified. Compared with those without a desmosome gene mutation, individuals with a desmosome gene mutation had earlier-onset ARVD/C and were more likely to have ventricular tachycardia.

SOURCE:

Circulation: Cardiovascular Genetics.2009; 2: 428-435

Published online before print June 3, 2009,

doi: 10.1161/ CIRCGENETICS.109.858217

 

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Large-Scale Candidate Gene Analysis in Whites and African Americans Identifies IL6R Polymorphism in Relation to Atrial Fibrillation

The National Heart, Lung, and Blood Institute’s Candidate Gene Association Resource (CARe) Project

Renate B. Schnabel, MD, MSc*, Kathleen F. Kerr, PhD*, Steven A. Lubitz, MD*, Ermeg L. Alkylbekova, MD*, Gregory M. Marcus, MD, MAS, Moritz F. Sinner, MD, Jared W. Magnani, MD, Philip A. Wolf, MD, Rajat Deo, MD, Donald M. Lloyd-Jones, MD, ScM, Kathryn L. Lunetta, PhD, Reena Mehra, MD, MS, Daniel Levy, MD, Ervin R. Fox, MD, MPH, Dan E. Arking, PhD, Thomas H. Mosley, PhD, Martina Müller-Nurasyid, MSc, PhD, Taylor R. Young, MA, H.-Erich Wichmann, MD, PhD, Sudha Seshadri, MD, Deborah N. Farlow, PhD, Jerome I. Rotter, MD, Elsayed Z. Soliman, MD, MSc, MS, Nicole L. Glazer, PhD, James G. Wilson, MD, Monique M.B. Breteler, MD, Nona Sotoodehnia, MD, MPH, Christopher Newton-Cheh, MD, MPH, Stefan Kääb, MD, PhD, Patrick T. Ellinor, MD, PhD*, Alvaro Alonso, MD*, Emelia J. Benjamin, MD, ScM*, Susan R. Heckbert, MD, PhD* and for the Candidate Gene Association Resource (CARe) Atrial Fibrillation/Electrocardiography Working Group

Correspondence to Susan R. Heckbert, MD, PhD, Cardiovascular Health Research Unit, University of Washington, 1730 Minor Ave, Suite 1360, Seattle, WA 98101. E-mail heckbert@u.washington.edu; Emelia J. Benjamin, MD, ScM, Medicine and Epidemiology, Boston University Schools of Medicine and Public Health, The Framingham Heart Study, 73 Mount Wayte Ave, Framingham, MA 01702–5827. E-mail emelia@bu.edu; Renate B. Schnabel, MD, MSc, Department of Medicine 2, Cardiology, Johannes Gutenberg University, Langenbeckstr 1, 55131 Mainz, Germany. E-mail schnabelr@gmx.de

↵* These authors contributed equally to the manuscript.

Abstract

Background—The genetic background of atrial fibrillation (AF) in whites and African Americans is largely unknown. Genes in cardiovascular pathways have not been systematically investigated.

Methods and Results—We examined a panel of approximately 50 000 common single-nucleotide polymorphisms (SNPs) in 2095 cardiovascular candidate genes and AF in 3 cohorts with participants of European (n=18 524; 2260 cases) or African American descent (n=3662; 263 cases) in the National Heart, Lung, and Blood Institute’s Candidate Gene Association Resource. Results in whites were followed up in the German Competence Network for AF (n=906, 468 cases). The top result was assessed in relation to incident ischemic stroke in the Cohorts for Heart and Aging Research in Genomic Epidemiology Stroke Consortium (n=19 602 whites, 1544 incident strokes). SNP rs4845625 in the IL6R gene was associated with AF (relative risk [RR] C allele, 0.90; 95% confidence interval [CI], 0.85–0.95; P=0.0005) in whites but did not reach statistical significance in African Americans (RR, 0.86; 95% CI, 0.72–1.03; P=0.09). The results were comparable in the German AF Network replication, (RR, 0.71; 95% CI, 0.57–0.89; P=0.003). No association between rs4845625 and stroke was observed in whites. The known chromosome 4 locus near PITX2 in whites also was associated with AF in African Americans (rs4611994; hazard ratio, 1.40; 95% CI, 1.16–1.69; P=0.0005).

Conclusions—In a community-based cohort meta-analysis, we identified genetic association in IL6R with AF in whites. Additionally, we demonstrated that the chromosome 4 locus known from recent genome-wide association studies in whites is associated with AF in African Americans.

 SOURCE:

Circulation: Cardiovascular Genetics.2011; 4: 557-564

Published online before print August 16, 2011,

doi: 10.1161/ CIRCGENETICS.110.959197

PITX2c Is Expressed in the Adult Left Atrium, and Reducing Pitx2c Expression Promotes Atrial Fibrillation Inducibility and Complex Changes in Gene Expression

Paulus Kirchhof, MD*, Peter C. Kahr*, Sven Kaese, Ilaria Piccini, PhD, Ismail Vokshi, BSc, Hans-Heinrich Scheld, MD, Heinrich Rotering, MD, Lisa Fortmueller, MD (vet), Sandra Laakmann, MD (vet), Sander Verheule, PhD, Ulrich Schotten, MD, PhD, Larissa Fabritz, MD and Nigel A. Brown, PhD

Author Affiliations

From the Department of Cardiology and Angiology (P.K., P.C.K., S.K., I.P., L.F., S.L., L.F.) and the Department of Thoracic and Cardiovascular Surgery (H.-H.S., H.R.), University Hospital Muenster, Germany; Division of Biomedical Sciences (P.C.K., I.V., N.A.B.), St. George’s, University of London, United Kingdom; and the Department of Physiology (S.V., U.S.), Maastricht University, The Netherlands.

Correspondence to Nigel A. Brown, PhD, Division of Biomedical Sciences, St George’s, University of London, Cranmer Terrace, London, SW17 0RE, UK. E-mail nbrown@sgul.ac.uk

↵* Drs Kirchhof and Kahr contributed equally to this work.

Abstract

Background— Intergenic variations on chromosome 4q25, close to the PITX2 transcription factor gene, are associated with atrial fibrillation (AF). We therefore tested whether adult hearts express PITX2 and whether variation in expression affects cardiac function.

Methods and Results— mRNA for PITX2 isoform c was expressed in left atria of human and mouse, with levels in right atrium and left and right ventricles being 100-fold lower. In mice heterozygous for Pitx2c (Pitx2c+/−), left atrial Pitx2c expression was 60% of wild-type and cardiac morphology and function were not altered, except for slightly elevated pulmonary flow velocity. Isolated Pitx2c+/− hearts were susceptible to AF during programmed stimulation. At short paced cycle lengths, atrial action potential durations were shorter in Pitx2c+/− than in wild-type. Perfusion with the β-receptor agonist orciprenaline abolished inducibility of AF and reduced the effect on action potential duration. Spontaneous heart rates, atrial conduction velocities, and activation patterns were not affected in Pitx2c+/− hearts, suggesting that action potential duration shortening caused wave length reduction and inducibility of AF. Expression array analyses comparing Pitx2c+/− with wild-type, for left atrial and right atrial tissue separately, identified genes related to calcium ion binding, gap and tight junctions, ion channels, and melanogenesis as being affected by the reduced expression of Pitx2c.

Conclusions— These findings demonstrate a physiological role for PITX2 in the adult heart and support the hypothesis that dysregulation of PITX2 expression can be responsible for susceptibility to AF.

 SOURCE:

Circulation: Cardiovascular Genetics.2011; 4: 123-133

Published online before print January 31, 2011,

doi: 10.1161/ CIRCGENETICS.110.958058

 

Genetics of CVD and Hyperlipidemia, Hyper Cholesterolemia, Metabolic Syndrome

 

Genetic Loci Associated With Plasma Concentration of Low-Density Lipoprotein Cholesterol, High-Density Lipoprotein Cholesterol, Triglycerides, Apolipoprotein A1, and Apolipoprotein B Among 6382 White Women in Genome-Wide Analysis With Replication

Daniel I. Chasman, PhD*, Guillaume Paré, MD, MS*, Robert Y.L. Zee, PhD, MPH, Alex N. Parker, PhD, Nancy R. Cook, ScD, Julie E. Buring, ScD, David J. Kwiatkowski, MD, PhD, Lynda M. Rose, MS, Joshua D. Smith, BS, Paul T. Williams, PhD, Mark J. Rieder, PhD, Jerome I. Rotter, MD, Deborah A. Nickerson, PhD, Ronald M. Krauss, MD, Joseph P. Miletich, MD and Paul M Ridker, MD, MPH

Author Affiliations

From the Center for Cardiovascular Disease Prevention (D.I.C., G.P., R.Y.L.Z., N.R.C., J.E.B., L.M.R., P.M.R.) and Donald W. Reynolds Center for Cardiovascular Research (D.I.C., G.P., R.Y.L.Z., N.R.C., D.J.K., P.M.R.), Brigham and Women’s Hospital, Harvard Medical School, Boston, Mass; Amgen, Inc, Cambridge, Mass (A.N.P., J.M.P.); Department of Genome Sciences, University of Washington, Seattle, Wash (J.D.S., M.J.R., D.A.N.); Life Science Division, Lawrence Berkeley National Laboratory, Berkeley, Calif (P.T.W., R.M.K.); Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, Calif (J.I.R.); and Children’s Hospital Oakland Research Institute, Oakland, Calif (R.M.K.).

Correspondence to Daniel I. Chasman, Center for Cardiovascular Disease Prevention, Brigham and Women’s Hospital, 900 Commonwealth Ave E, Boston, MA 02215. E-mail dchasman@rics.bwh.harvard.edu

Abstract

Background— Genome-wide genetic association analysis represents an opportunity for a comprehensive survey of the genes governing lipid metabolism, potentially revealing new insights or even therapeutic strategies for cardiovascular disease and related metabolic disorders.

Methods and Results— We have performed large-scale, genome-wide genetic analysis among 6382 white women with replication in 2 cohorts of 970 additional white men and women for associations between common single-nucleotide polymorphisms and low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein (Apo) A1, and ApoB. Genome-wide associations (P<5×10−8) were found at the PCSK9 gene, the APOB gene, the LPL gene, the APOA1-APOA5 locus, the LIPC gene, the CETP gene, the LDLR gene, and the APOE locus. In addition, genome-wide associations with triglycerides at the GCKR gene confirm and extend emerging links between glucose and lipid metabolism. Still other genome-wide associations at the 1p13.3 locus are consistent with emerging biological properties for a region of the genome, possibly related to the SORT1 gene. Below genome-wide significance, our study provides confirmatory evidence for associations at 5 novel loci with low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triglycerides reported recently in separate genome-wide association studies. The total proportion of variance explained by common variation at the genome-wide candidate loci ranges from 4.3% for triglycerides to 12.6% for ApoB.

Conclusion— Genome-wide associations at the GCKR gene and near the SORT1 gene, as well as confirmatory associations at 5 additional novel loci, suggest emerging biological pathways for lipid metabolism among white women.

 SOURCE:

Circulation: Cardiovascular Genetics.2008; 1: 21-30

doi: 10.1161/ CIRCGENETICS.108.773168

 

 

Integrated Computational and Experimental Analysis of the Neuroendocrine Transcriptome in Genetic Hypertension Identifies Novel Control Points for the Cardiometabolic Syndrome

Ryan S. Friese, PhD, Chun Ye, PhD, Caroline M. Nievergelt, PhD, Andrew J. Schork, BS, Nitish R. Mahapatra, PhD, Fangwen Rao, MD, Philip S. Napolitan, BS, Jill Waalen, MD, MPH, Georg B. Ehret, MD, Patricia B. Munroe, PhD, Geert W. Schmid-Schönbein, PhD, Eleazar Eskin, PhD and Daniel T. O’Connor, MD

Author Affiliations

From the Departments of Bioengineering (R.S.F., G.W.S.-S.), Medicine (R.S.F., A.J.S., F.R., P.S.N., D.T.O.), Pharmacology (D.T.O.), and Psychiatry (C.M.N.), the Bioinformatics Program (C.Y.), and the Institute for Genomic Medicine (D.T.O.), University of California at San Diego; the VA San Diego Healthcare System, San Diego, CA (D.T.O.); the Departments of Computer Science & Human Genetics, University of California at Los Angeles (E.E.); the Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India (N.R.M.); Clinical Pharmacology and The Genome Centre, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom (P.B.M.); Center for Complex Disease Genomics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (G.B.E.); and Scripps Research Institute, La Jolla, CA (J.W.).

Correspondence to Daniel T. O’Connor, MD, Department of Medicine, University of California at San Diego School of Medicine, VASDHS (0838), Skaggs (SSPPS) Room 4256, 9500 Gilman Drive, La Jolla, CA 92093-0838. E-mail doconnor@ucsd.edu

Abstract

Background—Essential hypertension, a common complex disease, displays substantial genetic influence. Contemporary methods to dissect the genetic basis of complex diseases such as the genomewide association study are powerful, yet a large gap exists betweens the fraction of population trait variance explained by such associations and total disease heritability.

Methods and Results—We developed a novel, integrative method (combining animal models, transcriptomics, bioinformatics, molecular biology, and trait-extreme phenotypes) to identify candidate genes for essential hypertension and the metabolic syndrome. We first undertook transcriptome profiling on adrenal glands from blood pressure extreme mouse strains: the hypertensive BPH (blood pressure high) and hypotensive BPL (blood pressure low). Microarray data clustering revealed a striking pattern of global underexpression of intermediary metabolism transcripts in BPH. The MITRA algorithm identified a conserved motif in the transcriptional regulatory regions of the underexpressed metabolic genes, and we then hypothesized that regulation through this motif contributed to the global underexpression. Luciferase reporter assays demonstrated transcriptional activity of the motif through transcription factors HOXA3, SRY, and YY1. We finally hypothesized that genetic variation at HOXA3, SRY, and YY1 might predict blood pressure and other metabolic syndrome traits in humans. Tagging variants for each locus were associated with blood pressure in a human population blood pressure extreme sample with the most extensive associations for YY1 tagging single nucleotide polymorphism rs11625658 on systolic blood pressure, diastolic blood pressure, body mass index, and fasting glucose. Meta-analysis extended the YY1 results into 2 additional large population samples with significant effects preserved on diastolic blood pressure, body mass index, and fasting glucose.

Conclusions—The results outline an innovative, systematic approach to the genetic pathogenesis of complex cardiovascular disease traits and point to transcription factor YY1 as a potential candidate gene involved in essential hypertension and the cardiometabolic syndrome.

 SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 430-440

Published online before print June 5, 2012,

doi: 10.1161/ CIRCGENETICS.111.962415

 

Associations Between Incident Ischemic Stroke Events and Stroke and Cardiovascular Disease-Related Genome-Wide Association Studies Single Nucleotide Polymorphisms in the Population Architecture Using Genomics and Epidemiology Study

Cara L. Carty, PhD, Petra Bůžková, PhD, Myriam Fornage, PhD, Nora Franceschini, MD, Shelley Cole, PhD, Gerardo Heiss, MD, PhD, Lucia A. Hindorff, PhD, MPH, Barbara V. Howard, PhD, Sue Mann, MPH, Lisa W. Martin, MD, Ying Zhang, PhD, Tara C. Matise, PhD, Ross Prentice, PhD, Alexander P. Reiner, MD, MS and Charles Kooperberg, PhD

Author Affiliations

From the Public Health Sciences, Fred Hutchinson Cancer Research Center (C.L.C., S.M., R.P., C.K.); Department of Biostatistics, University of Washington, Seattle, WA (P.B.); Institute of Molecular Medicine, University of Texas Health Sciences Center at Houston, Houston, TX (M.F.); Division of Epidemiology, School of Public Health, University of Texas Health Sciences Center, Houston, TX (M.F.); Department of Epidemiology, University of North Carolina, Chapel Hill, NC (N.F., G.H.); Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX (S.C.); Office of Population Genomics, National Human Genome Research Institute, Bethesda, MD (L.A.H.); Medstar Health Research Institute, Washington, DC (B.V.H.); George Washington University School of Medicine, Washington, DC (B.V.H., L.W.M.); University of Oklahoma Health Sciences Center, Oklahoma City, OK (Y.Z.); Department of Genetics, Rutgers University, Piscataway, NJ (T.C.M.); Department of Epidemiology, University of Washington, Seattle, WA (A.P.R.).

Correspondence to Dr Cara L. Carty, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N./M3-A410, Seattle, WA 98109. E-mail ccarty@fhcrc.org

Abstract

Background—Genome-wide association studies (GWAS) have identified loci associated with ischemic stroke (IS) and cardiovascular disease (CVD) in European-descent individuals, but their replication in different populations has been largely unexplored.

Methods and Results—Nine single nucleotide polymorphisms (SNPs) selected from GWAS and meta-analyses of stroke, and 86 SNPs previously associated with myocardial infarction and CVD risk factors, including blood lipids (high density lipoprotein [HDL], low density lipoprotein [LDL], and triglycerides), type 2 diabetes, and body mass index (BMI), were investigated for associations with incident IS in European Americans (EA) N=26 276, African-Americans (AA) N=8970, and American Indians (AI) N=3570 from the Population Architecture using Genomics and Epidemiology Study. Ancestry-specific fixed effects meta-analysis with inverse variance weighting was used to combine study-specific log hazard ratios from Cox proportional hazards models. Two of 9 stroke SNPs (rs783396 and rs1804689) were associated with increased IS hazard in AA; none were significant in this large EA cohort. Of 73 CVD risk factor SNPs tested in EA, 2 (HDL and triglycerides SNPs) were associated with IS. In AA, SNPs associated with LDL, HDL, and BMI were significantly associated with IS (3 of 86 SNPs tested). Out of 58 SNPs tested in AI, 1 LDL SNP was significantly associated with IS.

Conclusions—Our analyses showing lack of replication in spite of reasonable power for many stroke SNPs and differing results by ancestry highlight the need to follow up on GWAS findings and conduct genetic association studies in diverse populations. We found modest IS associations with BMI and lipids SNPs, though these findings require confirmation.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 210-216

Published online before print March 8, 2012,

doi: 10.1161/ CIRCGENETICS.111.962191

 

Common Variation in Fatty Acid Genes and Resuscitation From Sudden Cardiac Arrest

Catherine O. Johnson, PhD, MPH, Rozenn N. Lemaitre, PhD, MPH, Carol E. Fahrenbruch, MSPH, Stephanie Hesselson, PhD, Nona Sotoodehnia, MD, MPH, Barbara McKnight, PhD, Kenneth M. Rice, PhD, Pui-Yan Kwok, MD, PhD, David S. Siscovick, MD, MPH and Thomas D. Rea, MD, MPH

Author Affiliations

From the Departments of Medicine (C.O.J., R.N.L., N.S., D.S.S., T.D.R.), Biostatistics (B.M., K.M.R.), and Epidemiology (D.S.S), University of Washington, Seattle; King County Emergency Medical Services, Seattle, WA (C.E.F.); and Institute of Human Genetics, University of California San Francisco (S.H., P.-Y.K.).

Correspondence to Catherine O. Johnson, PhD, MPH, Department of Medicine, University of Washington, CHRU 1730 Minor Ave, Suite 1360, Seattle, WA 98101. E-mail johnsoco@uw.edu

Abstract

Background—Fatty acids provide energy and structural substrates for the heart and brain and may influence resuscitation from sudden cardiac arrest (SCA). We investigated whether genetic variation in fatty acid metabolism pathways was associated with SCA survival.

Methods and Results—Subjects (mean age, 67 years; 80% male, white) were out-of-hospital SCA patients found in ventricular fibrillation in King County, WA. We compared subjects who survived to hospital admission (n=664) with those who did not (n=689), and subjects who survived to hospital discharge (n=334) with those who did not (n=1019). Associations between survival and genetic variants were assessed using logistic regression adjusting for age, sex, location, time to arrival of paramedics, whether the event was witnessed, and receipt of bystander cardiopulmonary resuscitation. Within-gene permutation tests were used to correct for multiple comparisons. Variants in 5 genes were significantly associated with SCA survival. After correction for multiple comparisons, single-nucleotide polymorphisms in ACSL1 and ACSL3 were significantly associated with survival to hospital admission. Single-nucleotide polymorphisms in ACSL3, AGPAT3, MLYCD, and SLC27A6 were significantly associated with survival to hospital discharge.

Conclusions—Our findings indicate that variants in genes important in fatty acid metabolism are associated with SCA survival in this population.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 422-429

Published online before print June 1, 2012,

doi: 10.1161/ CIRCGENETICS.111.961912

 

Genome-Wide Association Study Pinpoints a New Functional Apolipoprotein B Variant Influencing Oxidized Low-Density Lipoprotein Levels But Not Cardiovascular Events

AtheroRemo Consortium

Kari-Matti Mäkelä, BM, BSc, Ilkka Seppälä, MSc, Jussi A. Hernesniemi, MD, PhD, Leo-Pekka Lyytikäinen, MD, Niku Oksala, MD, PhD, DSc, Marcus E. Kleber, PhD, Hubert Scharnagl, PhD, Tanja B. Grammer, MD, Jens Baumert, PhD, Barbara Thorand, PhD, Antti Jula, MD, PhD, Nina Hutri-Kähönen, MD, PhD, Markus Juonala, MD, PhD, Tomi Laitinen, MD, PhD, Reijo Laaksonen, MD, PhD, Pekka J. Karhunen, MD, PhD, Kjell C. Nikus, MD, PhD, Tuomo Nieminen, MD, PhD, MSc, Jari Laurikka, MD, PhD, Pekka Kuukasjärvi, MD, PhD, Matti Tarkka, MD, PhD, Jari Viik, PhD, Norman Klopp, PhD, Thomas Illig, PhD, Johannes Kettunen, PhD, Markku Ahotupa, PhD, Jorma S.A. Viikari, MD, PhD, Mika Kähönen, MD, PhD, Olli T. Raitakari, MD, PhD, Mahir Karakas, MD, Wolfgang Koenig, MD, PhD, Bernhard O. Boehm, MD, Bernhard R. Winkelmann, MD, Winfried März, MD and Terho Lehtimäki, MD, PhD

Correspondence to Kari-Matti Mäkelä, Department of Clinical Chemistry, Finn-Medi 2, PO Box 2000, FI-33521 Tampere, Finland. E-mail kari-matti.makela@uta.fi

Abstract

Background—Oxidized low-density lipoprotein may be a key factor in the development of atherosclerosis. We performed a genome-wide association study on oxidized low-density lipoprotein and tested the impact of associated single-nucleotide polymorphisms (SNPs) on the risk factors of atherosclerosis and cardiovascular events.

Methods and Results—A discovery genome-wide association study was performed on a population of young healthy white individuals (N=2080), and the SNPs associated with a P<5×10–8 were replicated in 2 independent samples (A: N=2912; B: N=1326). Associations with cardiovascular endpoints were also assessed with 2 additional clinical cohorts (C: N=1118; and D: N=808). We found 328 SNPs associated with oxidized low-density lipoprotein. The genetic variant rs676210 (Pro2739Leu) in apolipoprotein B was the proxy SNP behind all associations (P=4.3×10–136, effect size=13.2 U/L per allele). This association was replicated in the 2 independent samples (A and B, P=2.5×10–47 and 1.1×10–11, effect sizes=10.3 U/L and 7.8 U/L, respectively). In the meta-analyses of cohorts A, C, and D (excluding cohort B without angiographic data), the top SNP did not associate significantly with the age of onset of angiographically verified coronary artery disease (hazard ratio=1.00 [0.94–1.06] per allele), 3-vessel coronary artery disease (hazard ratio=1.03 [0.94–1.13]), or myocardial infarction (hazard ratio=1.04 [0.96–1.12]).

Conclusions—This novel genetic marker is an important factor regulating oxidized low-density lipoprotein levels but not a major genetic factor for the studied cardiovascular endpoints.

 SOURCE:

Circulation: Cardiovascular Genetics.2013; 6: 73-81

Published online before print December 17, 2012,

doi: 10.1161/ CIRCGENETICS.112.964965

Genome-Wide Screen for Metabolic Syndrome Susceptibility Loci Reveals Strong Lipid Gene Contribution But No Evidence for Common Genetic Basis for Clustering of Metabolic Syndrome Traits

Kati Kristiansson, PhD, Markus Perola, MD, PhD, Emmi Tikkanen, MSc, Johannes Kettunen, PhD, Ida Surakka, MSc, Aki S. Havulinna, DSc (Tech.), Alena Stančáková, MD, PhD, Chris Barnes, PhD, Elisabeth Widen, MD, PhD, Eero Kajantie, MD, PhD, Johan G. Eriksson, MD, DMSc, Jorma Viikari, MD, PhD, Mika Kähönen, MD, PhD, Terho Lehtimäki, MD, PhD, Olli T. Raitakari, MD, PhD, Anna-Liisa Hartikainen, MD, PhD, Aimo Ruokonen, MD, PhD, Anneli Pouta, MD, PhD, Antti Jula, MD, PhD, Antti J. Kangas, MSc, Pasi Soininen, PhD, Mika Ala-Korpela, PhD, Satu Männistö, PhD, Pekka Jousilahti, MD, PhD, Lori L. Bonnycastle, PhD, Marjo-Riitta Järvelin, MD, PhD, Johanna Kuusisto, MD, PhD, Francis S. Collins, MD, PhD, Markku Laakso, MD, PhD, Matthew E. Hurles, PhD, Aarno Palotie, MD, PhD, Leena Peltonen, MD, PhD*, Samuli Ripatti, PhD and Veikko Salomaa, MD, PhD

Correspondence to Dr Kati Kristiansson, National Institute for Health and Welfare, University of Helsinki, Biomedicum, PL 104, FI-00251 Helsinki, Finland. E-mail kati.kristiansson@thl.fi

Abstract

Background—Genome-wide association (GWA) studies have identified several susceptibility loci for metabolic syndrome (MetS) component traits, but have had variable success in identifying susceptibility loci to the syndrome as an entity. We conducted a GWA study on MetS and its component traits in 4 Finnish cohorts consisting of 2637 MetS cases and 7927 controls, both free of diabetes, and followed the top loci in an independent sample with transcriptome and nuclear magnetic resonance-based metabonomics data. Furthermore, we tested for loci associated with multiple MetS component traits using factor analysis, and built a genetic risk score for MetS.

Methods and Results—A previously known lipid locus, APOA1/C3/A4/A5 gene cluster region (SNP rs964184), was associated with MetS in all 4 study samples (P=7.23×10−9 in meta-analysis). The association was further supported by serum metabolite analysis, where rs964184 was associated with various very low density lipoprotein, triglyceride, and high-density lipoprotein metabolites (P=0.024–1.88×10−5). Twenty-two previously identified susceptibility loci for individual MetS component traits were replicated in our GWA and factor analysis. Most of these were associated with lipid phenotypes, and none with 2 or more uncorrelated MetS components. A genetic risk score, calculated as the number of risk alleles in loci associated with individual MetS traits, was strongly associated with MetS status.

Conclusions—Our findings suggest that genes from lipid metabolism pathways have the key role in the genetic background of MetS. We found little evidence for pleiotropy linking dyslipidemia and obesity to the other MetS component traits, such as hypertension and glucose intolerance.

 SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 242-249

Published online before print March 7, 2012,

doi: 10.1161/ CIRCGENETICS.111.961482

 

Genetics and Vascular Pathologies and Platelet Aggregation, Cardiac Troponin T in Serum

 

 

TGFβRIIb Mutations Trigger Aortic Aneurysm Pathogenesis by Altering Transforming Growth Factor β2 Signal Transduction

Katharine J. Bee, PhD, David C. Wilkes, PhD, Richard B. Devereux, MD, Craig T. Basson, MD, PhD and Cathy J. Hatcher, PhD

Author Affiliations

From the Center for Molecular Cardiology, Greenberg Division of Cardiology, Weill Cornell Medical College, New York, NY.

Correspondence to Cathy J. Hatcher, PhD, Greenberg Division of Cardiology, Weill Cornell Medical College, 525 E. 68th St, New York, NY 10065. E-mail cjhatche@med.cornell.edu

Abstract

Background—Thoracic aortic aneurysm (TAA) is a common progressive disorder involving gradual dilation of the ascending and/or descending thoracic aorta that eventually leads to dissection or rupture. Nonsydromic TAA can occur as a genetically triggered, familial disorder that is usually transmitted in a monogenic autosomal dominant fashion and is known as familial TAA. Genetic analyses of families affected with TAA have identified several chromosomal loci, and further mapping of familial TAA genes has highlighted disease-causing mutations in at least 4 genes: myosin heavy chain 11 (MYH11), α-smooth muscle actin (ACTA2), and transforming growth factor β receptors I and II (TGFβRI and TGFβRII).

Methods and Results—We evaluated 100 probands to determine the mutation frequency in MYH11, ACTA2, TGFβRI, and TGFβRII in an unbiased population of individuals with genetically mediated TAA. In this study, 9% of patients had a mutation in one of the genes analyzed, 3% of patients had mutations in ACTA2, 3% in MYH11, 1% in TGFβRII, and no mutations were found in TGFβRI. Additionally, we identified mutations in a 75 base pair alternatively spliced TGFβRII exon, exon 1a that produces the TGFβRIIb isoform and accounted for 2% of patients with mutations. Our in vitro analyses indicate that the TGFβRIIb activating mutations alter receptor function on TGFβ2 signaling.

Conclusions—We propose that TGFβRIIb expression is a regulatory mechanism for TGFβ2 signal transduction. Dysregulation of the TGFβ2 signaling pathway, as a consequence of TGFβRIIb mutations, results in aortic aneurysm pathogenesis.

SOURCE: 

Circulation: Cardiovascular Genetics.2012; 5: 621-629

Published online before print October 24, 2012,doi: 10.1161/​CIRCGENETICS.112.964064

Matrix Metalloproteinase-9 Genotype as a Potential Genetic Marker for Abdominal Aortic Aneurysm

Tyler Duellman, BS, Christopher L. Warren, PhD, Peggy Peissig, PhD, Martha Wynn, MD and Jay Yang, MD, PhD

Author Affiliations

From the Molecular and Cellular Pharmacology Graduate Program (T.D., J.Y.) and Department of Anesthesiology (M.W., J.Y.), University of Wisconsin School of Medicine and Public Health, Madison; Illumavista Biosciences LLC, Madison, WI (C.L.W.); and Biomedical Informatics Research Center, Marshfield Clinics Research Foundation, Marshfield, WI (P.P.).

Correspondence to Jay Yang, MD, PhD, Department of Anesthesiology, University of Wisconsin SMPH, SMI 301, 1300 University Ave, Madison, WI 53706. E-mail Jyang75@wisc.edu

Abstract

Background—Degradation of extracellular matrix support in the large abdominal arteries contribute to abnormal dilation of aorta, leading to abdominal aortic aneurysms, and matrix metalloproteinase-9 (MMP-9) is the predominant enzyme targeting elastin and collagen present in the walls of the abdominal aorta. Previous studies have suggested a potential association between MMP-9 genotype and abdominal aortic aneurysm, but these studies have been limited only to the p-1562 and (CA) dinucleotide repeat microsatellite polymorphisms in the promoter region of the MMP-9 gene. We determined the functional alterations caused by 15 MMP-9 single-nucleotide polymorphisms (SNPs) reported to be relatively abundant in the human genome through Western blots, gelatinase, and promoter–reporter assays and incorporated this information to perform a logistic-regression analysis of MMP-9 SNPs in 336 human abdominal aortic aneurysm cases and controls.

Methods and Results—Significant functional alterations were observed for 6 exon SNPs and 4 promoter SNPs. Genotype analysis of frequency-matched (age, sex, history of hypertension, hypercholesterolemia, and smoking) cases and controls revealed significant genetic heterogeneity exceeding 20% observed for 6 SNPs in our population of mostly white subjects from Northern Wisconsin. A step-wise logistic-regression analysis with 6 functional SNPs, where weakly contributing confounds were eliminated using Akaike information criteria, gave a final 2 SNP (D165N and p-2502) model with an overall odds ratio of 2.45 (95% confidence interval, 1.06–5.70).

Conclusions—The combined approach of direct experimental confirmation of the functional alterations of MMP-9 SNPs and logistic-regression analysis revealed significant association between MMP-9 genotype and abdominal aortic aneurysm.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 529-537

Published online before print August 31, 2012,

doi: 10.1161/ CIRCGENETICS.112.963082

Common Genetic Variation in the 3′–BCL11B Gene Desert Is Associated With Carotid-Femoral Pulse Wave Velocity and Excess Cardiovascular Disease Risk

The AortaGen Consortium

Gary F. Mitchell, MD*, Germaine C. Verwoert, MSc*, Kirill V. Tarasov, MD, PhD*, Aaron Isaacs, PhD, Albert V. Smith, PhD, Yasmin, BSc, MA, PhD, Ernst R. Rietzschel, MD, PhD, Toshiko Tanaka, PhD, Yongmei Liu, MD, PhD, Afshin Parsa, MD, MPH, Samer S. Najjar, MD, Kevin M. O’Shaughnessy, MA, BM, DPhil, FRCP, Sigurdur Sigurdsson, MSc, Marc L. De Buyzere, MSc, Martin G. Larson, ScD, Mark P.S. Sie, MD, PhD, Jeanette S. Andrews, MS, Wendy S. Post, MD, MS, Francesco U.S. Mattace-Raso, MD, PhD, Carmel M. McEniery, BSc, PhD, Gudny Eiriksdottir, MSc, Patrick Segers, PhD, Ramachandran S. Vasan, MD, Marie Josee E. van Rijn, MD, PhD, Timothy D. Howard, PhD, Patrick F. McArdle, PhD, Abbas Dehghan, MD, PhD, Elizabeth S. Jewell, MS, Stephen J. Newhouse, MSc, PhD, Sofie Bekaert, PhD, Naomi M. Hamburg, MD, Anne B. Newman, MD, MPH, Albert Hofman, MD, PhD, Angelo Scuteri, MD, PhD, Dirk De Bacquer, PhD, Mohammad Arfan Ikram, MD, PhD†, Bruce M. Psaty, MD, PhD†, Christian Fuchsberger, PhD‡, Matthias Olden, PhD‡, Louise V. Wain, PhD§, Paul Elliott, MB, PhD§, Nicholas L. Smith, PhD‖, Janine F. Felix, MD, PhD‖, Jeanette Erdmann, PhD¶, Joseph A. Vita, MD, Kim Sutton-Tyrrell, PhD, Eric J.G. Sijbrands, MD, PhD, Serena Sanna, PhD, Lenore J. Launer, MS, PhD, Tim De Meyer, PhD, Andrew D. Johnson, MD, Anna F.C. Schut, MD, PhD, David M. Herrington, MD, MHS, Fernando Rivadeneira, MD, PhD, Manuela Uda, PhD, Ian B. Wilkinson, MA, BM, FRCP, Thor Aspelund, PhD, Thierry C. Gillebert, MD, PhD, Luc Van Bortel, MD, PhD, Emelia J. Benjamin, MD, MSc, Ben A. Oostra, PhD, Jingzhong Ding, MD, PhD, Quince Gibson, MBA, André G. Uitterlinden, PhD, Gonçalo R. Abecasis, PhD, John R. Cockcroft, BSc, MB, ChB, FRCP, Vilmundur Gudnason, MD, PhD, Guy G. De Backer, MD, PhD, Luigi Ferrucci, MD, Tamara B. Harris, MD, MS, Alan R. Shuldiner, MD, Cornelia M. van Duijn, PhD, Daniel Levy, MD*, Edward G. Lakatta, MD* and Jacqueline C.M. Witteman, PhD*

Correspondence to Gary F. Mitchell, MD, Cardiovascular Engineering, Inc, 1 Edgewater Dr, Suite 201A, Norwood, MA 02062. E-mail GaryFMitchell@mindspring.com

↵* These authors contributed equally.

Abstract

Background—Carotid-femoral pulse wave velocity (CFPWV) is a heritable measure of aortic stiffness that is strongly associated with increased risk for major cardiovascular disease events.

Methods and Results—We conducted a meta-analysis of genome-wide association data in 9 community-based European ancestry cohorts consisting of 20 634 participants. Results were replicated in 2 additional European ancestry cohorts involving 5306 participants. Based on a preliminary analysis of 6 cohorts, we identified a locus on chromosome 14 in the 3′-BCL11B gene desert that is associated with CFPWV (rs7152623, minor allele frequency=0.42, β=−0.075±0.012 SD/allele, P=2.8×10−10; replication β=−0.086±0.020 SD/allele, P=1.4×10−6). Combined results for rs7152623 from 11 cohorts gave β=−0.076±0.010 SD/allele, P=3.1×10−15. The association persisted when adjusted for mean arterial pressure (β=−0.060±0.009 SD/allele, P=1.0×10−11). Results were consistent in younger (<55 years, 6 cohorts, n=13 914, β=−0.081±0.014 SD/allele, P=2.3×10−9) and older (9 cohorts, n=12 026, β=−0.061±0.014 SD/allele, P=9.4×10−6) participants. In separate meta-analyses, the locus was associated with increased risk for coronary artery disease (hazard ratio=1.05; confidence interval=1.02–1.08; P=0.0013) and heart failure (hazard ratio=1.10, CI=1.03–1.16, P=0.004).

Conclusions—Common genetic variation in a locus in the BCL11B gene desert that is thought to harbor 1 or more gene enhancers is associated with higher CFPWV and increased risk for cardiovascular disease. Elucidation of the role this novel locus plays in aortic stiffness may facilitate development of therapeutic interventions that limit aortic stiffening and related cardiovascular disease events.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 81-90

Published online before print November 8, 2011,

doi: 10.1161/ CIRCGENETICS.111.959817

Genetic Variation in PEAR1 is Associated with Platelet Aggregation and Cardiovascular Outcomes

Joshua P. Lewis1, Kathleen Ryan1, Jeffrey R. O’Connell1, Richard B. Horenstein1, Coleen M. Damcott1, Quince Gibson1, Toni I. Pollin1, Braxton D. Mitchell1, Amber L. Beitelshees1, Ruth Pakzy1, Keith Tanner1, Afshin Parsa1, Udaya S. Tantry2, Kevin P. Bliden2, Wendy S. Post3, Nauder Faraday3, William Herzog4, Yan Gong5, Carl J. Pepine6, Julie A. Johnson5, Paul A. Gurbel2 and Alan R. Shuldiner7*

Author Affiliations

1University of Maryland School of Medicine, Baltimore, MD

2Sinai Hospital of Baltimore, Baltimore, MD

3Johns Hopkins University School of Medicine, Baltimore, MD

4Sinai Hospital of Baltimore & Johns Hopkins University School of Medicine, Baltimore, MD

5University of Florida College of Pharmacy, Gainesville, FL

6University of Florida College of Medicine, Gainesville, FL

7University of Maryland School of Medicine & Veterans Administration Medical Center, Baltimore, MD

↵* University of Maryland School of Medicine & Veterans Administration Medical Center, Baltimore, MD ashuldin@medicine.umaryland.edu

Abstract

Background-Aspirin or dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is standard therapy for patients at increased risk for cardiovascular events. However, the genetic determinants of variable response to aspirin (alone and in combination with clopidogrel) are not known.

Methods and Results-We measured ex-vivo platelet aggregation before and after DAPT in individuals (n=565) from the Pharmacogenomics of Antiplatelet Intervention (PAPI) Study and conducted a genome-wide association study (GWAS) of drug response. Significant findings were extended by examining genotype and cardiovascular outcomes in two independent aspirin-treated cohorts: 227 percutaneous coronary intervention (PCI) patients, and 1,000 patients of the International VErapamil SR/trandolapril Study (INVEST) GENEtic Substudy (INVEST-GENES). GWAS revealed a strong association between single nucleotide polymorphisms on chromosome 1q23 and post-DAPT platelet aggregation. Further genotyping revealed rs12041331 in the platelet endothelial aggregation receptor-1 (PEAR1) gene to be most strongly associated with DAPT response (P=7.66×10-9). In Caucasian and African American patients undergoing PCI, A-allele carriers of rs12041331 were more likely to experience a cardiovascular event or death compared to GG homozygotes (hazard ratio = 2.62, 95%CI 0.96-7.10, P=0.059 and hazard ratio = 3.97, 95%CI 1.10-14.31, P=0.035 respectively). In aspirin-treated INVEST-GENES patients, rs12041331 A-allele carriers had significantly increased risk of myocardial infarction compared to GG homozygotes (OR=2.03, 95%CI 1.01-4.09, P=0.048).

Conclusions-Common genetic variation in PEAR1 may be a determinant of platelet response and cardiovascular events in patients on aspirin, alone and in combination with clopidogrel.

Clinical Trial Registration Information-clinicaltrials.gov; Identifiers: NCT00799396 and NCT00370045

SOURCE:

CIRCGENETICS.112.964627

Published online before print February 7, 2013,

doi: 10.1161/ CIRCGENETICS.111.964627

Association of Genome-Wide Variation With Highly Sensitive Cardiac Troponin-T Levels in European Americans and Blacks

A Meta-Analysis From Atherosclerosis Risk in Communities and Cardiovascular Health Studies

Bing Yu, MD, MSc, Maja Barbalic, PhD, Ariel Brautbar, MD, Vijay Nambi, MD, Ron C. Hoogeveen, PhD, Weihong Tang, PhD, Thomas H. Mosley, PhD, Jerome I. Rotter, MD, Christopher R. deFilippi, MD, Christopher J. O’Donnell, MD, Sekar Kathiresan, MD, Ken Rice, PhD, Susan R. Heckbert, MD, PhD, Christie M. Ballantyne, MD, Bruce M. Psaty, MD, PhD and Eric Boerwinkle, PhD on behalf of the CARDIoGRAM Consortium

Author Affiliations

From the Human Genetic Center, University of Texas Health Science Center at Houston, Houston, TX (B.Y., M.B., E.B.); Deptartment of Medicine (A.B., V.N., R.C.H., C.M.B.), and Human Genome Sequencing Center (E.B.), Baylor College of Medicine, Houston, TX; Department of Epidemiology, University of Minnesota, Minneapolis, MN (W.T.); Division of Geriatrics, University of Mississippi Medical Center, Jackson, MS (T.H.M.); Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, CA (J.I.R.); School of Medicine, University of Maryland, Baltimore, MD (C.R.D.); National Heart, Lung, and Blood Institute and Framingham Heart Study, National Institutes of Health, Bethesda, MD (C.J.O.D.); Center for Human Genetic Research & Cardiovascular Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, MA (S.K.); Department of Biostatistics (K.R.), and Cardiovascular Health Research Unit & Department of Epidemiology (S.R.H.), University of Washington, Seattle, WA; and Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Services, University of Washington & Group Health Research Institute, Group Health Cooperative, Seattle, WA (B.M.P.).

Correspondence to Eric Boerwinkle, PhD, Human Genetic Center, University of Texas School of Public Health, 1200 Herman Pressler E-447, Houston, TX 77030. E-mail Eric.Boerwinkle@uth.tmc.edu

Abstract

Background—High levels of cardiac troponin T, measured by a highly sensitive assay (hs-cTnT), are strongly associated with incident coronary heart disease and heart failure. To date, no large-scale genome-wide association study of hs-cTnT has been reported. We sought to identify novel genetic variants that are associated with hs-cTnT levels.

Methods and Results—We performed a genome-wide association in 9491 European Americans and 2053 blacks free of coronary heart disease and heart failure from 2 prospective cohorts: the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study. Genome-wide association studies were conducted in each study and race stratum. Fixed-effect meta-analyses combined the results of linear regression from 2 cohorts within each race stratum and then across race strata to produce overall estimates and probability values. The meta-analysis identified a significant association at chromosome 8q13 (rs10091374; P=9.06×10−9) near the nuclear receptor coactivator 2 (NCOA2) gene. Overexpression of NCOA2 can be detected in myoblasts. An additional analysis using logistic regression and the clinically motivated 99th percentile cut point detected a significant association at 1q32 (rs12564445; P=4.73×10−8) in the gene TNNT2, which encodes the cardiac troponin T protein itself. The hs-cTnT-associated single-nucleotide polymorphisms were not associated with coronary heart disease in a large case-control study, but rs12564445 was significantly associated with incident heart failure in Atherosclerosis Risk in Communities Study European Americans (hazard ratio=1.16; P=0.004).

Conclusions—We identified 2 loci, near NCOA2 and in the TNNT2 gene, at which variation was significantly associated with hs-cTnT levels. Further use of the new assay should enable replication of these results.

 SOURCE:

Circulation: Cardiovascular Genetics.2013; 6: 82-88

Published online before print December 16, 2012,

doi: 10.1161/ CIRCGENETICS.112.963058

 

Genomics and Valvular Disease

 

Supravalvular Aortic Stenosis Elastin Arteriopathy

 

Giuseppe Merla, PhD, Nicola Brunetti-Pierri, MD, Pasquale Piccolo, PhD, Lucia Micale, PhD and Maria Nicla Loviglio, PhD, MSc

Author Affiliations

From the Medical Genetics Unit, IRCCS Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy (G.M., L.M., M.N.L.); Telethon Institute of Genetics and Medicine, Napoli, Italy (N.B-P., P.P.); Department of Pediatrics, Federico II University of Naples, Naples, Italy (N.B-P.); and CIG Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland (M.N.L.).

Correspondence to Giuseppe Merla, PhD, Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza, viale Cappuccini, 71013 San Giovanni Rotondo, Italy. E-mail g.merla@operapadrepio.it

Abstract

Supravalvular aortic stenosis is a systemic elastin (ELN) arteriopathy that disproportionately affects the supravalvular aorta. ELN arteriopathy may be present in a nonsyndromic condition or in syndromic conditions such as Williams–Beuren syndrome. The anatomic findings include congenital narrowing of the lumen of the aorta and other arteries, such as branches of pulmonary or coronary arteries. Given the systemic nature of the disease, accurate evaluation is recommended to establish the degree and extent of vascular involvement and to plan appropriate interventions, which are indicated whenever hemodynamically significant stenoses occur. ELN arteriopathy is genetically heterogeneous and occurs as a consequence of haploinsufficiency of the ELN gene on chromosome 7q11.23, owing to either microdeletion of the entire chromosomal region or ELN point mutations. Interestingly, there is a prevalence of premature termination mutations resulting in null alleles among ELN point mutations. The identification of the genetic defect in patients with supravalvular aortic stenosis is essential for a definitive diagnosis, prognosis, and genetic counseling.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 692-696

doi: 10.1161/ CIRCGENETICS.112.962860

Genetic Loci for Coronary Calcification and Serum Lipids Relate to Aortic and Carotid Calcification

Daniel Bos, MD, M. Arfan Ikram, MD, PhD, Aaron Isaacs, PhD, Benjamin F.J. Verhaaren, MD, Albert Hofman, MD, PhD, Cornelia M. van Duijn, PhD, Jacqueline C.M. Witteman, PhD, Aad van der Lugt, MD, PhD and Meike W. Vernooij, MD, PhD

Author Affiliations

From the Departments of Radiology (D.B., M.A.I., B.F.J.V., A.v.d.L., M.W.V), Epidemiology (D.B., M.A.I., A.I., B.F.J.V., A.H., C.M.v.D., J.C.M.W., M.W.V.), and Genetic Epidemiology Unit (A.I., C.M.v.D.), Erasmus MC, Rotterdam, the Netherlands.

Correspondence to Meike W. Vernooij, MD, PhD, Department of Radiology, Erasmus MC, Gravendijkwal 230, PO Box 2040, 3000CA Rotterdam, the Netherlands. E-mail m.vernooij@erasmusmc.nl

Abstract

Background—Atherosclerosis in different vessel beds shares lifestyle and environmental risk factors. It is unclear whether this holds for genetic risk factors. Hence, for the current study genetic loci for coronary artery calcification and serum lipid levels, one of the strongest risk factors for atherosclerosis, were used to assess their relation with atherosclerosis in different vessel beds.

Methods and Results—From 1987 persons of the population-based Rotterdam Study, 3 single-nucleotide polymorphisms (SNPs) for coronary artery calcification and 132 SNPs for total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglycerides were used. To quantify atherosclerotic calcification as a marker of atherosclerosis, all participants underwent nonenhanced computed tomography of the aortic arch and carotid arteries. Associations between genetic risk scores of the joint effect of the SNPs and of all calcification were investigated. The joint effect of coronary artery calcification–SNPs was associated with larger calcification volumes in all vessel beds (difference in calcification volume per SD increase in genetic risk score: 0.15 [95% confidence interval, 0.11–0.20] in aorta, 0.14 [95% confidence interval, 0.10–0.18] in extracranial carotids, and 0.11 [95% confidence interval, 0.07–0.16] in intracranial carotids). The joint effect of total cholesterol SNPs, low-density lipoprotein SNPs, and of all lipid SNPs together was associated with larger calcification volumes in both the aortic arch and the carotid arteries but attenuated after adjusting for the lipid fraction and lipid-lowering medication.

Conclusions—The genetic basis for aortic arch and carotid artery calcification overlaps with the most important loci of coronary artery calcification. Furthermore, serum lipids share a genetic predisposition with both calcification in the aortic arch and the carotid arteries, providing novel insights into the cause of atherosclerosis.

 SOURCE:

Circulation: Cardiovascular Genetics.2013; 6: 47-53

Published online before print December 16, 2012,

doi: 10.1161/ CIRCGENETICS.112.963934

 

Joint Associations of 61 Genetic Variants in the Nicotinic Acetylcholine Receptor Genes with Subclinical Atherosclerosis in American Indians

A Gene-Family Analysis

Jingyun Yang, PhD*, Yun Zhu, MS*, Elisa T. Lee, PhD, Ying Zhang, PhD, Shelley A. Cole, PhD, Karin Haack, PhD, Lyle G. Best, BS MD, Richard B. Devereux, MD, Mary J. Roman, MD, Barbara V. Howard, PhD and Jinying Zhao, MD, PhD

Author Affiliations

From the Tulane University School of Public Health and Tropical Medicine, New Orleans, LA (J.Y., Y. Zhu, J.Z.); Center for American Indian Health Research, University of Oklahoma Health Sciences Center, Oklahoma City, OK (E.T.L., Y. Zhang); Texas Biomedical Research Institute, San Antonio, TX (S.A.C., K.H.); Missouri Breaks Industries Research Inc, Timber Lake, SD (L.G.B.); The New York Hospital-Cornell Medical Center, New York, NY (R.B.D., M.J.R.); MedStar Health Research Institute, Hyattsville, MD (B.V.H.); and Georgetown and Howard Universities Centers for Translational Sciences, Washington, DC (B.V.H.).

Correspondence to Jinying Zhao, MD, PhD, Department of Epidemiology, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal St, SL18, New Orleans, LA 70112. E-mail jzhao5@tulane.edu

↵* These authors contributed equally to this work.

Abstract

Background—Atherosclerosis is the underlying cause of cardiovascular disease, the leading cause of morbidity and mortality in all American populations, including American Indians. Genetic factors play an important role in the pathogenesis of atherosclerosis. Although a single-nucleotide polymorphism (SNP) may explain only a small portion of variability in disease, the joint effect of multiple variants in a pathway on disease susceptibility could be large.

Methods and Results—Using a gene-family analysis, we investigated the joint associations of 61 tag SNPs in 7 nicotinic acetylcholine receptor genes with subclinical atherosclerosis, as measured by carotid intima-media thickness and plaque score, in 3665 American Indians from 94 families recruited by the Strong Heart Family Study (SHFS). Although multiple SNPs showed marginal association with intima-media thickness and plaque score individually, only a few survived adjustments for multiple testing. However, simultaneously modeling of the joint effect of all 61 SNPs in 7 nicotinic acetylcholine receptor genes revealed significant association of the nicotinic acetylcholine receptor gene family with both intima-media thickness and plaque score independent of known coronary risk factors.

Conclusions—Genetic variants in the nicotinic acetylcholine receptor gene family jointly contribute to subclinical atherosclerosis in American Indians who participated in the SHFS. These variants may influence the susceptibility of atherosclerosis through pathways other than cigarette smoking per se.

SOURCE:

Circulation: Cardiovascular Genetics.2013; 6: 89-96

Published online before print December 22, 2012,

doi: 10.1161/ CIRCGENETICS.112.963967

 

 

Heredity of Cardiovascular Disorders Inheritance

 

A Clinical Approach to Common Cardiovascular Disorders When There Is a Family History

The Implications of Inheritance for Clinical Management

Srijita Sen-Chowdhry, MBBS, MD, FESC, Daniel Jacoby, MD and William J. McKenna, MD, DSc, FESC

Author Affiliations

From the Institute of Cardiovascular Science, University College London, London, United Kingdom (S.S-C., W.J.M.); Department of Epidemiology, Imperial College, London, London, United Kingdom (S.S-C.); Division of Cardiology, Yale School of Medicine, New Haven, CT (D.J., W.J.M.).

Correspondence to Professor William J. McKenna, MD, DSc, FESC, Institute of Cardiovascular Science, University College London, The Heart Hospital, 16-18 Westmoreland Street, London, E-mail william.mckenna@uclh.nhs.uk

Introduction

Since the advent of genotyping, recognition of heritable disease has been perceived as an opportunity for genetic diagnosis or new gene identification studies to advance understanding of pathogenesis. Until recently, however, clinical application of DNA-based testing was confined largely to Mendelian disorders. Even within this remit, predictive testing of relatives is cost-effective only in diseases in which the majority of families harbor mutations in known causal genes, such as adult polycystic kidney disease and hypertrophic cardiomyopathy, but not dilated cardiomyopathy. Confirmatory genetic testing of index cases with borderline clinical features may be economic in the still smaller subset of diseases with limited locus heterogeneity, such as Marfan syndrome. Furthermore, Mendelian diseases account for ≈5% of total disease burden.1 Genome-wide association studies have made headway in elucidating the genetic contribution to the more common, complex diseases, and high throughput techniques promise to facilitate integration of genetic analysis into clinical practice. Nevertheless, many genes remain to be identified and implementation of genomic profiling as a population screening tool would not be cost-effective at present. The implications of heredity, however, extend beyond serving as a platform for genetic analysis, influencing diagnosis, prognostication, and treatment of both index cases and relatives, and enabling rational targeting of genotyping resources. This review covers acquisition of a family history, evaluation of heritability and inheritance patterns, and the impact of inheritance on subsequent components of the clinical pathway.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 467-476

doi: 10.1161/ CIRCGENETICS.110.959361

Clinical Considerations of Heritable Factors in Common Heart Failure

Thomas P. Cappola, MD, ScM and Gerald W. Dorn II, MD

Author Affiliations

From the Department of Medicine, University of Pennsylvania, Philadelphia, PA (T.P.C.), and Center for Pharmacogenomics, Washington University School of Medicine, St Louis, MO (G.W.D.II.).

Correspondence to Gerald W. Dorn II, MD, Center for Pharmacogenomics, Washington University, 660 S Euclid Ave, Campus Box 8220, St Louis, MO 63110. E-mail gdorn@dom.wustl.edu

 

Introduction

Heart failure is a common condition responsible for at least 290 000 deaths each year in the United States alone.1 A small minority of heart failure cases are attributed to Mendelian or familial cardiomyopathies. The majority of systolic heart failure cases are not familial but represent the end result of 1 or many conditions that primarily injure the myocardium sufficiently to diminish cardiac output in the absence of compensatory mechanisms. Paradoxically, because they also injure the myocardium, it is the chronic actions of the compensatory mechanisms that in many instances contribute to the progression from simple cardiac injury to dilated cardiomyopathy and overt heart failure. Thus, the epidemiology of common heart failure appears to be just as sporadic as its major antecedent conditions (atherosclerosis, diabetes, hypertension, and viral myocarditis).

Familial trends in preclinical cardiac remodeling2 and risk of developing heart failure3 reveal an important role for genetic modifiers in addition to clinical and environmental factors. Candidate gene studies performed over the past 10 years have identified a few polymorphic gene variants that modify risk or progression of common heart failure.4 Whole-genome sequencing will lead to the discovery of other genetic modifiers that were not candidates.5 The imminent availability of individual whole-genome sequences at a cost competitive with available genetic tests for familial cardiomyopathy will no doubt further expand the list of putative genetic heart failure modifiers. Heart failure risk alleles along with traditional clinical factors will need to be considered by clinical cardiologists in their design of optimal disease surveillance and prevention programs and in individually tailoring heart failure management.

The use of individual genetic make-up is likely to have the earliest and greatest impact on managing patients with heart failure by tailoring available pharmacotherapeutics to optimize patient response and minimize adverse effects (ie, the area of pharmacogenetics). Modern heart failure management has been derived and directed by the results of large, randomized, multicenter clinical trials. When standard therapies are applied according to the selection criteria used in these trials, they prolong average survival across affected populations or decrease the incidence of heart failure in populations at risk.6 For this reason, standardized treatment guidelines prescribe heart failure therapies according to trial designs, aiming for the same target doses and general treatment approaches,7 and largely ignore individual characteristics. In this article, we review established and emerging knowledge of genetic influence on common heart failure and try to anticipate how these genetic factors may be best used to eschew the cookie-cutter approach to heart failure management and move toward implementing a personalized medicine approach for the treatment and prevention of this important and prevalent disease.

The Concept of Genotype-Directed Personal Medical Management in Heart Failure

Variation in clinical heart failure progression and therapeutic response (either benefits or side effects) supports the need for a more individualized approach to disease management. On the basis of clinical stratification (eg, by etiology of heart failure as ischemic versus nonischemic, functional status, comorbid disease), physicians try to match each patient’s specific heart failure syndrome with a therapeutic regime devised to provide the most benefit. Standard heart failure pharmacotherapy currently comprises a minimum of 3 medications (angiotensin-converting enzyme [ACE] inhibitors, β-blockers, and aldosterone antagonists), with consideration of additional medications (hydralazine/isosorbide, angiotensin receptor blockers) and diuretics. The recommended target dosages for these agents, derived from their respective clinical trials, is rarely achieved,8 partly because of untoward clinical side effects such as low blood pressure or renal dysfunction. Accordingly, the published guidelines most often are applied in each individual patient using ad hoc approaches derived from personal experience and the “art of medicine.”

Technological advances in human genomics promise a different approach and are bringing cardiology into an era of clinically applied pharmacogenetics9 (whether we want to or not). As sequencing costs decline, it is not hard to envision that patients will present having had their entire genome already sequenced. The imperative to apply genome information in clinical settings will increase, as demonstrated by recent proof-of-concept studies.10 Our field seems poorly prepared for this type of evolution in care; Roden et al9 identified 3 major barriers: First is the absence of rapidly available genotype information in the clinical workflow. This barrier is being overcome with whole-genome sequencing, which (with proper analysis) promises a permanent and largely immutable genetic roadmap for individual disease risk and drug response at a cost comparable to many other clinical tests.11 Second, we must have the knowledge to properly apply information on genetic variants for the diseases we are managing and the drugs we are using. As we describe, this knowledge is accumulating for heart failure and for other cardiac conditions, and the rate at which we are gaining additional information and developing further expertise appears to be accelerating.

The third and perhaps most formidable barrier is the lack of clinical evidence showing how real-time application of genetic information can best benefit patients. As has been broadly communicated to the medical community and lay public, common functional gene variants in CYP2C19 can impair the transformation of clopidogrel into its active metabolite, leading to increased risk of stent thrombosis after percutaneous coronary intervention.12 The relevant question thus becomes the following: If physicians have this information at the time of clinical care and reacted by adjusting clopidogrel dose or substituting prasugrel, which is unaffected by CYP2C19 genotype,13 would there be any improvement in clinical outcome? It is also important to consider whether any observed benefits justify the additional costs of genetic testing and for the alternate drug. Studies are currently examining these questions, and similar clinical trials will prospectively examine whether a genotype-guided strategy of warfarin dosing will be superior to the standard genotype-blinded approach in reaching target anticoagulation goals. At this time, there are no similar prospective, randomized, blinded trials of genotype-guided care for common heart failure.

Emerging Variants

The variants described here are established, but new ones are emerging. Although findings in heart failure genome-wide association studies have been limited, we can expect additional common heart failure variants to emerge as sample sizes increase.65 The CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) consortium published a genome-wide association study of incident heart failure that tested for associations between >2.4 million HapMap-imputed polymorphisms in >20 000 subjects.7 They identified 2 loci associated with heart failure, rs10519210 (15q22, containing USP3 encoding a ubiquitin-specific protease) in subjects of European ancestry and rs11172782 (12q14, containing LRIG3 encoding a leucine-rich, immunoglobulin-like domain-containing protein of uncertain function) in subjects of African ancestry.66 In a companion study using the same population and genotyping results, mortality analysis of the subgroup of individuals who developed heart failure implicated an intronic SNP in CMTM7 (CKLF-like MARVEL transmembrane domain-containing 7).67 These genetic associations require independent replication and further study to identify the underlying biological mechanisms.

A recently published genome-wide association study by a European consortium on dilated cardiomyopathy identified common variants in BAG3 (BCL2-associated athanogene 3) associated with heart failure57 and identified rare BAG3 missense and truncation mutations that segregate with familial cardiomyopathy. These findings were consistent with an earlier exome-sequencing study that identified BAG3 as a familial dilated cardiomyopathy gene and showed recapitulation of cardiomyopathy with BAG3 morpholino knockdown in zebra fish.68 Together, these studies convincingly support variation in BAG3 as a genetic risk factor of cardiomyopathy and heart failure. It is noteworthy that both common and rare functional variations were identified at this locus. A unifying hypothesis for these findings, which needs to be formally tested, is that common variants in BAG3 serve as proxies for rare functional BAG3 mutations with large effects. In this situation, the underlying genetic lesion is a rare variant with a large functional effect. This has recently been described for common variants in MYH6 that correlated with rare functional MYH6 variants to cause sick sinus syndrome.69 It is premature to speculate on the clinical applications of these newer findings.

Moving Knowledge to Practice

A small number of genomic variants have been identified that modify heart failure by affecting well-understood physiological systems. The principal barrier preventing their adoption in practice may be lack of evidence showing how application of this information can best be used for clinical benefit. Trials testing genotype targeting of antiplatelet therapy and anticoagulation will be completed in the coming years. The findings from these studies will likely determine the level of enthusiasm for conducting genotype-guided trials of β-blockers and RAAS antagonists in heart failure. Given that the lifetime risk of heart failure in the United States is estimated at 1 in 5, even a small favorable effect on heart failure prevention or outcome through use of genome-guided therapy has the potential for a large public health impact. We therefore believe that a near-term goal should be to conduct pharmacogenomic trials in heart failure based on our current understanding of heart failure variants.

Looking ahead, unbiased approaches will continue to reveal a large number heart failure-modifying variants (both common and rare). Based on experience in other complex phenotypes, such has height70 and plasma lipid levels,71 the underlying genetic mechanisms for many new heart failure variants will be completely unknown, and their sheer number will preclude detailed experimentation using murine models to figure them out. Leveraging these variants for clinical application is a challenge that we will be forced to confront.

As our ability to identify rare, disease-causing variants improves through personal genome sequencing, we will be faced with the additional problem of how best to estimate the disease risk conferred by a sequence variant for which there has been no biological validation. In probabilistic terms, because there are 3 billion nucleotides in the human genome and over twice that many humans on the planet, it is likely that a nucleotide substitution for every position is represented in someone. Obviously, it will be impossible to recombinantly express and functionally characterize every DNA variant that is going to be implicated in heart failure. Bioinformatics filters have been used to try and separate functionally significant from insignificant variants based on the likelihood of changing transcript expression or protein function. These tools are limited but will improve if we tailor their results to the known characteristics of each gene product. For example, current approaches to categorize amino acid substitutions as conservative or nonconservative based only on charge or side chains can be improved by molecular modeling that incorporates protein-specific structure-function information. This approach has been used to estimate the pathogenicity of myosin heavy chain (MHC) mutations in an effort to determine which mutations are likely to cause familial cardiomyopathy when linkage analysis is not feasible.72 In concept, this approach can be applied to any protein for which structure-function activities have been finely mapped to distinct domains.

A promising extension of this approach may be to use evolutionary genetics to infer disease causality. Again, using the MHC genes as examples, human genome data show a greater prevalence of nonsynonymous gene variants in MYH6, which encodes the minor cardiac α-MHC isoform, compared with the adjacent MYH7, which encodes the major β-MHC isoform. This disparity suggests a greater tolerance for protein changes in the α-MHC isoform and negative selection against these in β-MHC. We can infer, therefore, that amino acid changes are more likely to have adverse impacts in MYH7-encoded β-MHC. If this paradigm survives prospective testing, then the forthcoming explosion of individual genetic data not only will present a massive problem in interpretation, but also will provide the genetic information by which analyses of rare sequence variants across large unaffected populations can help to differentiate the tolerable variants from those that are more likely to alter disease risk.

Each Reference above is found in:

http://circgenetics.ahajournals.org/content/4/6/701.full

SOURCE: 

Circulation: Cardiovascular Genetics.2011; 4: 701-709

doi: 10.1161/ CIRCGENETICS.110.959379

 

Pharmacogenomics

 

Hypertension Susceptibility Loci and Blood Pressure Response to Antihypertensives

Results From the Pharmacogenomic Evaluation of Antihypertensive Responses Study

Yan Gong, PhD, Caitrin W. McDonough, PhD, Zhiying Wang, MS, Wei Hou, PhD, Rhonda M. Cooper-DeHoff, PharmD, MS, Taimour Y. Langaee, PhD, Amber L. Beitelshees, PharmD, MPH, Arlene B. Chapman, MD, John G. Gums, PharmD, Kent R. Bailey, PhD, Eric Boerwinkle, PhD, Stephen T. Turner, MD and Julie A. Johnson, PharmD

Author Affiliations

From the Department of Pharmacotherapy and Translational Research (Y.G., C.W.M., R.M.C.-D., T.Y.L., J.G.G., J.A.J.), Department of Biostatistics, College of Medicine (W.H.), Division of Cardiovascular Medicine, College of Medicine (R.M.C.-D., J.A.J.), and Department of Community Health and Family Medicine (J.G.G.), University of Florida, Gainesville, FL; Division of Epidemiology, University of Texas at Houston, Houston, TX (Z.W., E.B.); Division of Endocrinology, Diabetes and Nutrition, University of Maryland, Baltimore, MD (A.L.B.); Renal Division, Emory University, Atlanta, GA (A.B.C.); and Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN (S.T.T.).

Correspondence to Yan Gong, PhD, Department of Pharmacotherapy and Translational Research, University of Florida, PO Box 100486, 1600 SW Archer Rd, Gainesville, FL 32610. E-mail gong@cop.ufl.edu.

Abstract

Background—To date, 39 single nucleotide polymorphisms (SNPs) have been associated with blood pressure (BP) or hypertension in genome-wide association studies in whites. Our hypothesis is that the loci/SNPs associated with BP/hypertension are also associated with BP response to antihypertensive drugs.

Methods and Results—We assessed the association of these loci with BP response to atenolol or hydrochlorothiazide monotherapy in 768 hypertensive participants in the Pharmacogenomics Responses of Antihypertensive Responses study. Linear regression analysis was performed on whites for each SNP in an additive model adjusting for baseline BP, age, sex, and principal components for ancestry. Genetic scores were constructed to include SNPs with nominal associations, and empirical P values were determined by permutation test. Genotypes of 37 loci were obtained from Illumina 50K cardiovascular or Omni1M genome-wide association study chips. In whites, no SNPs reached Bonferroni-corrected α of 0.0014, 6 reached nominal significance (P<0.05), and 3 were associated with atenolol BP response at P<0.01. The genetic score of the atenolol BP-lowering alleles was associated with response to atenolol (P=3.3×10–6 for systolic BP; P=1.6×10–6 for diastolic BP). The genetic score of the hydrochlorothiazide BP-lowering alleles was associated with response to hydrochlorothiazide (P=0.0006 for systolic BP; P=0.0003 for diastolic BP). Both risk score P values were <0.01 based on the empirical distribution from the permutation test.

Conclusions—These findings suggest that selected signals from hypertension genome-wide association studies may predict BP response to atenolol and hydrochlorothiazide when assessed through risk scoring.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 686-691

Published online before print October 19, 2012,

doi: 10.1161/ CIRCGENETICS.112.964080

 

Genetic Determinants of Statin-Induced Low-Density Lipoprotein Cholesterol Reduction

The Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) Trial

Daniel I. Chasman, PhD, Franco Giulianini, PhD, Jean MacFadyen, BA, Bryan J. Barratt, PhD, Fredrik Nyberg, MD, PhD, MPH and Paul M Ridker, MD, MPH

Author Affiliations

From the Center for Cardiovascular Disease Prevention (D.I.C., F.G., J.M., P.M.R.), JUPITER Trial Coordinating Center (D.I.C., F.G., J.M., P.M.R.), Brigham and Women’s Hospital and Harvard Medical School (D.I.C., P.M.R.), Boston, MA; Personalised Healthcare and Biomarkers, AstraZeneca Research and Development, Alderley Park, United Kingdom (B.J.B.); AstraZeneca Research and Development, Mölndal, Sweden (F.N.); and Unit of Occupational and Environmental Medicine, Department of Public Health and Community Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden (F.N.).

Correspondence to Daniel I. Chasman, PhD, Center for Cardiovascular Disease Prevention, Brigham and Women’s Hospital, 900 Commonwealth Ave E, Boston, MA 02215. E-mail dchasman@rics.bwh.harvard.edu

Abstract

Background—In statin trials, each 20 mg/dL reduction in cholesterol results in a 10–15% reduction of annual incidence rates for vascular events. However, interindividual variation in low-density lipoprotein cholesterol (LDL-C) response to statins is wide and may partially be determined on a genetic basis.

Methods and Results—A genome-wide association study of LDL-C response was performed among a total of 6989 men and women of European ancestry who were randomly allocated to either rosuvastatin 20 mg daily or placebo. Single nucleotide polymorphisms (SNPs) for genome-wide association (P<5×10−8) with LDL-C reduction on rosuvastatin were identified at ABCG2, LPA, and APOE, and a further association at PCSK9 was genome-wide significant for baseline LDL-C and locus-wide significant for LDL-C reduction. Median LDL-C reductions on rosuvastatin were 40, 48, 51, 55, 60, and 64 mg/dL, respectively, among those inheriting increasing numbers of LDL-lowering alleles for SNPs at these 4 loci (P trend=6.2×10−20), such that each allele approximately doubled the odds of percent LDL-C reduction greater than the trial median (odds ratio, 1.9; 95% confidence interval, 1.8–2.1; P=5.0×10−41). An intriguing additional association with sub–genome-wide significance (P<1×10-6) was identified for statin related LDL-C reduction at IDOL, which mediates posttranscriptional regulation of the LDL receptor in response to intracellular cholesterol levels. In candidate analysis, SNPs in SLCO1B1 and LDLR were confirmed as associated with LDL-C lowering, and a significant interaction was observed between SNPs in PCSK9 and LDLR.

Conclusions—Inherited polymorphisms that predominantly relate to statin pharmacokinetics and endocytosis of LDL particles by the LDL receptor are common in the general population and influence individual patient response to statin therapy.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 257-264

Published online before print February 13, 2012,

doi: 10.1161/ CIRCGENETICS.111.961144

Genetic Variation in the β2 Subunit of the Voltage-Gated Calcium Channel and Pharmacogenetic Association With Adverse Cardiovascular Outcomes in the INternational VErapamil SR-Trandolapril STudy GENEtic Substudy (INVEST-GENES)

Yuxin Niu, PhD*, Yan Gong, PhD*, Taimour Y. Langaee, PhD, Heather M. Davis, PharmD, Hazem Elewa, PhD, Amber L. Beitelshees, PharmD, MPH, James I. Moss, PhD, Rhonda M. Cooper-DeHoff, PharmD, Carl J. Pepine, MD and Julie A. Johnson, PharmD

Author Affiliations

From the Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics (Y.N., Y.G., T.Y.L., H.M.D., H.E., J.I.M., R.M.C.-D., J.A.J.), College of Pharmacy, University of Florida, Gainesville, Fla; Division of Endocrinology, Diabetes and Nutrition (A.L.B.), University of Maryland School of Medicine, Baltimore, Md; and Division of Cardiovascular Medicine (R.M.C.-D., C.J.P., J.A.J.), University of Florida College of Medicine, Gainesville, Fla.

Correspondence to Julie A. Johnson, PharmD, Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, PO Box 100486, Gainesville, FL 32610. E-mail Johnson@cop.ufl.edu

↵* Drs Niu and Gong contributed equally to this work.

Abstract

Background— Single-nucleotide polymorphisms (SNPs) within the regulatory β2 subunit of the voltage-gated calcium channel (CACNB2) may contribute to variable treatment response to antihypertensive drugs and adverse cardiovascular outcomes.

Methods and Results— SNPs in CACNB2 from 60 ethnically diverse individuals were identified and characterized. Three common SNPs (rs2357928, rs7069292, and rs61839258) and a genome-wide association study-identified intronic SNP (rs11014166) were genotyped for a clinical association study in 5598 hypertensive patients with coronary artery disease randomized to a β-blocker (BB) or a calcium channel blocker (CCB) treatment strategy in the INternational VErapamil SR-Trandolapril STudy GENEtic Substudy (INVEST-GENES). Reporter gene assays were conducted on the promoter SNP, showing association with clinical outcomes. Twenty-one novel SNPs were identified. A promoter A>G SNP (rs2357928) was found to have significant interaction with treatment strategy for adverse cardiovascular outcomes (P for interaction, 0.002). In whites, rs2357928 GG patients randomized to CCB were more likely to experience an adverse outcome than those randomized to BB treatment strategy, with adjusted hazard ratio (HR) (CCB versus BB) of 2.35 (95% CI, 1.19 to 4.66; P=0.014). There was no evidence for such treatment difference in AG (HR, 1.16; 95% CI, 0.75 to 1.79; P=0.69) and AA (HR, 0.63; 95% CI, 0.36 to 1.11; P=0.11) patients. This finding was consistent in Hispanics and blacks. CACNB2 rs11014166 showed similar pharmacogenetic effect in Hispanics, but not in whites or blacks. Reporter assay analysis of rs2357928 showed a significant increase in promoter activity for the G allele compared to the A allele.

Conclusions— These data suggest that genetic variation within CACNB2 may influence treatment-related outcomes in high-risk patients with hypertension.

Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00133692.

SOURCE:

Circulation: Cardiovascular Genetics.2010; 3: 548-555

doi: 10.1161/ CIRCGENETICS.110.957654

 

Hepatic Metabolism and Transporter Gene Variants Enhance Response to Rosuvastatin in Patients With Acute Myocardial Infarction

The GEOSTAT-1 Study

Kristian M. Bailey, MBChB, Simon P.R. Romaine, BSc, Beryl M. Jackson, RGN, Amanda J. Farrin, MSc, Maria Efthymiou, MSc, Julian H. Barth, MD, Joanne Copeland, BSc, Terry McCormack, MBBS, Andrew Whitehead, MSc, Marcus D. Flather, MBBS, Nilesh J. Samani, MD, FMedSci, Jane Nixon, PhD, Alistair S. Hall, MD, PhD, Anthony J. Balmforth, PhD and on behalf of the SPACE ROCKET Trial Group

Author Affiliations

From the Division of Cardiovascular and Diabetes Research (K.M.B., S.P.R.R., B.M.J., A.J.B.), and Division of Cardiovascular and Neuronal Remodelling (A.S.H.), Multidisciplinary Cardiovascular Research Centre, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds, United Kingdom; Clinical Trials Research Unit (A.J.F., M.E., J.C., J.N.), University of Leeds, Leeds, United Kingdom; Clinical Biochemistry (J.H.B.), Leeds General Infirmary, Leeds, United Kingdom; Whitby Group Practice (T.M.), Spring Vale Medical Centre, Whitby, North Yorkshire, United Kingdom; Pharmacy Department (A.W.), Leeds General Infirmary, Leeds, United Kingdom; Clinical Trials and Evaluation Unit (M.D.F.), Royal Brompton and Harefield NHS Trust and Imperial College, London, United Kingdom; and Department of Cardiovascular Sciences (N.J.S.), University of Leicester, Leicester, United Kingdom.

Correspondence to Alistair S. Hall, Clinical Cardiology, Multidisciplinary Cardiovascular Research Centre (MCRC), G Floor, Jubilee Building, Leeds General Infirmary, Leeds, LS1 3EX, United Kingdom. E-mail A.S.Hall@leeds.ac.uk

* Dr Bailey, Mr Romaine, Dr Hall, and Dr Balmforth contributed equally to this study.

Abstract

Background— Pharmacogenetics aims to maximize benefits and minimize risks of drug treatment. Our objectives were to examine the influence of common variants of hepatic metabolism and transporter genes on the lipid-lowering response to statin therapy.

Methods and Results— The Genetic Effects On STATins (GEOSTAT-1) Study was a genetic substudy of Secondary Prevention of Acute Coronary Events—Reduction of Cholesterol to Key European Targets (SPACE ROCKET) (a randomized, controlled trial comparing 40 mg of simvastatin and 10 mg of rosuvastatin) that recruited 601 patients after myocardial infarction. We genotyped the following functional single nucleotide polymorphisms in the genes coding for the cytochrome P450 (CYP) metabolic enzymes, CYP2C9*2 (430C>T), CYP2C9*3 (1075A>C), CYP2C19*2 (681G>A), CYP3A5*1 (6986A>G), and hepatic influx and efflux transporters SLCO1B1 (521T>C) and breast cancer resistance protein (BCRP; 421C>A). We assessed 3-month LDL cholesterol levels and the proportion of patients reaching the current LDL cholesterol target of <70 mg/dL (<1.81 mmol/L). An enhanced response to rosuvastatin was seen for patients with variant genotypes of either CYP3A5 (P=0.006) or BCRP (P=0.010). Furthermore, multivariate logistic-regression analysis revealed that patients with at least 1 variant CYP3A5 and/or BCRP allele (n=186) were more likely to achieve the LDL cholesterol target (odds ratio: 2.289; 95% CI: 1.157, 4.527; P=0.017; rosuvastatin 54.0% to target vs simvastatin 33.7%). There were no differences for patients with variants of CYP2C9, CYP2C19, or SLCO1B1 in comparison with their respective wild types, nor were differential effects on statin response seen for patients with the most common genotypes for CYP3A5 and BCRP (n=415; odds ratio: 1.207; 95% CI: 0.768, 1.899; P=0.415).

Conclusion— The LDL cholesterol target was achieved more frequently for the 1 in 3 patients with CYP3A5 and/or BCRP variant genotypes when prescribed rosuvastatin 10 mg, compared with simvastatin 40 mg.

Clinical Trial Registration— URL: http://isrctn.org. Unique identifier: ISRCTN 89508434.

SOURCE:

Circulation: Cardiovascular Genetics.2010; 3: 276-285

Published online before print March 5, 2010,

doi: 10.1161/ CIRCGENETICS.109.898502

 

Comprehensive Whole-Genome and Candidate Gene Analysis for Response to Statin Therapy in the Treating to New Targets (TNT) Cohort

John F. Thompson, PhD, Craig L. Hyde, PhD, Linda S. Wood, MS, Sara A. Paciga, MA, David A. Hinds, PhD, David R. Cox, MD, PhD, G. Kees Hovingh, MD, PhD and John J.P. Kastelein, MD, PhD

Author Affiliations

From the Helicos BioSciences (J.F.T.), Cambridge, Mass; Molecular Medicine (J.F.T., L.S.W., S.A.P.) and Statistical Applications (C.L.H.), Pfizer Global Research and Development, Groton, Conn; Perlegen Sciences (D.A.H., D.R.C.), Mountain View, Calif; and Department of Vascular Medicine (G.K.H., J.J.P.K.), Academic Medical Center, Amsterdam, The Netherlands.

Correspondence to John J.P. Kastelein, MD, PhD, Department of Vascular Medicine, Academic Medical Center, Meibergdreef 9, Room F4-159.2, 1105 AZ Amsterdam, The Netherlands. E-mail j.j.kastelein@amc.uva.nl or j.s.jansen@amc.uva.nl

Abstract

Background— Statins are effective at lowering low-density lipoprotein cholesterol and reducing risk of cardiovascular disease, but variability in response is not well understood. To address this, 5745 individuals from the Treating to New Targets (TNT) trial were genotyped in a combination of a whole-genome and candidate gene approach to identify associations with response to atorvastatin treatment.

Methods and Results— A total of 291 988 single-nucleotide polymorphisms (SNPs) from 1984 individuals were analyzed for association with statin response, followed by genotyping top hits in 3761 additional individuals. None was significant at the whole-genome level in either the initial or follow-up test sets for association with low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triglyceride response. In addition to the whole-genome platform, 23 candidate genes previously associated with statin response were analyzed in these 5745 individuals. Three SNPs in apoE were most highly associated with low-density lipoprotein cholesterol response, followed by 1 in PCSK9 with a similar effect size. At the candidate gene level, SNPs in HMGCR were also significant though the effect was less than with those in apoE and PCSK9. rs7412/apoE had the most significant association (P=6×10−30), and its high significance in the whole-genome study (P=4×10−9) confirmed the suitability of this population for detecting effects. Age and gender were found to influence low-density lipoprotein cholesterol response to a similar extent as the most pronounced genetic effects.

Conclusions— Among SNPs tested with an allele frequency of at least 5%, only SNPs in apoE are found to influence statin response significantly. Less frequent variants in PCSK9 and smaller effect sizes in SNPs in HMGCR were also revealed.

SOURCE:

Circulation: Cardiovascular Genetics.2009; 2: 173-181

Published online before print February 12, 2009,

doi: 10.1161/ CIRCGENETICS.108.818062

Summary

Larry H. Bernstein, MD, FCAP

This review has examined a compendium of well regarded documents drawn from 248 articles in Circulation Cardiovascular Genetics from March 2010 to March 2013. The large amount of evidence obtained from large population studies identifying Genome Wide Analysis Studies (GWAS) examines a host of cardiac and vascular diseases in which there is association between specific single nucleotide peptides (SNPs), and gene loci, that may play or have no significant role in developing heart disease. It certainly is evidence of the role that the American Heart Association has is in supporting the leading research today for tomorrow’s patients.   It is too early to sort them out, but it speaks to a large volume of discovery in this area.

It raises another issue that we have been confronted with mostly since the second half of the 20th century.  What is that issue?  The issue, it appears to me, is the vast improvements in analytical technology so that “imprecision” is far less likely to be a confounder in biological measurements and this lends access to far better accuracy?  But from that question arises another! Accuracy only refers to what is measured, but does it give us better ability to explain a complex and dynamic process?  In other words, what is what we are looking at representative of in manageable events?   I think that this is the most important idea that should come out of the recent criticism of the trajectory that molecular genetics been on in the last 5 years.

It was still in an era that “BIG’ science was not the normal.  One could spend an enormous effort at stepwise purification of a protein or enzyme, or other biomolecule starting with a slurry made from 100 lbs of “chicken heart”, for example.  These separations were based on negative charges on the molecules and positive charges on the column, and the molecules of no interest were eluted by gradient elution.  Much was learned about large scale preparation from small scale trials.  But this work was not undertaken without the intent to carry out a number of investigations to understand the “functionality” of a link in a metabolic pathway.  The studies that followed the purification required kinetic investigation with a coenzyme, or with a synthetically modified coenzyme, amino acid sequencing, NMR studies, etc.  You could not put together a “mechanism” without having the minimum amount of necessary information for a reliable account.  It is probably this requirement that led to today’s “BIG” science, that is founded upon multiple methods, now large data bases, and teams of investigators across institutions and continents.  The acquisition of knowledge has been astounding, but the integration of knowledge has not caught up.

However, let’s see if we can sort out the most meaningful signals from what I too am beginning to call the “noisy channel”.  As often happens, important areas of research are opened up that are followed by significant discovery and, in the long run, many other dead end publications that have no lasting significance.  In order to do justice to the work, I’ll pick through documents I find interesting, keeping in mind there is a hidden layer of complexity of which only sufficient information leads to a better understanding.  As much literature calls attention to, much of what ails us has nothing to do with classical Mendelian genetics, and has a postgenomic component.

The most fascinating aspect of this is the withering “dark matter” of the genome. While that component may be silent or expressed, the understanding comes at a higher observed order.  The dark became light! The expression became subtle, like weak bond interactions. The underlying organization is a component of the adaptive ability of an organism or individual in an environment with plants and animals in a changing climate, at particular altitudes, with given water supplies, with disease vectors, and with endogenous sources of essential nutrients.  This brings into focus the regulatory role of the genome as just as important a factor as transmission of the genetic code, especially in somatic cell populations.

The remainder of this discussion deals specifically with my observations on cardiovascular genomics. The following conclusion is appropriate, if incomplete, at this time on circulating miRNAs, particularly miR-133a:

  • elevated levels of circulating miR-133a in patients with cardiovascular diseases originate mainly from the injured myocardium.
  • Circulating miR-133a can be used as a marker for cardiomyocyte death, and

A number of articles that cite this article suggest that it may be useful for following disease progression:
Plasma microRNAs serve as biomarkers of therapeutic efficacy and disease progression in hypertension-induced heart failure  Eur J Heart Fail  2013

MicroRNAs Within the Continuum of Postgenomics Biomarker Discovery Arterio. Thromb. Vasc. Bio. 2013;33:206-214

“Need for Rigor in Design, Reporting, and Interpretation of Transcriptomic Biomarker Studies”  J. Clin. Microbiol.. 2012;50:4192-4193

Circulating microRNAs as diagnostic biomarkers for cardiovascular diseases. Am. J. Physiol. Heart Circ. Physiol.. 2012;303:H1085-H1095,

Circulating MicroRNAs: Novel Biomarkers and Extracellular Communicators in Cardiovascular Disease? Circ. Res.. 2012;110:483-495

Circulating MicroRNAs: Biomarkers or Mediators of Cardiovascular Diseases?  Arterioscler. Thromb. Vasc. Bio. 2011;31:2383-2390,

Circulating MicroRNA-208b and MicroRNA-499 Reflect Myocardial Damage in Cardiovascular Disease MF Corsten, R Dennert, S Jochem, T Kuznetsova,  et al.

The finding refers to an association that is related to the appearance of a miRNA in the circulation of patients with acute cardiac ischemia, and particular released into the circulation of patients from injured myocardium.  This finding has to be distinguished from a finding of another miRNA released with acute injury.  In the case of miR499 (and miR208b), there is a comparison with plasma cTnT, and an ROC curve is produced.

The List of this follows:

Circulation: Cardiovascular Genetics 2010; 3: 499-506

Strikingly, in plasma from

  • acute myocardial infarction patients, cardiac myocyte–associated miR-208b and -499 were highly elevated, 1600-fold (P<0.005) and 100-fold (P<0.0005), respectively, as compared with control subjects. Receiver operating characteristic curve analysis revealed an area under the curve of 0.94 (P<10−10) for miR-208b and 0.92 (P<10−9) for miR-499. Both microRNAs correlated with plasma troponin T, indicating release of microRNAs from injured cardiomyocytes.
  • In patients with acute heart failure, only miR-499 was significantly elevated (2-fold), whereas
  • no significant changes in microRNAs studied could be observed in diastolic dysfunction.

Remarkably, plasma microRNA levels were not affected by a wide range of clinical confounders, including

  • age,
  • sex,
  • body mass index,
  • kidney function,
  • systolic blood pressure, and
  • white blood cell count.

This is miRNA with a different twist.  It appears that there are 3 types found in AMI (133a, 208b, 409).  But type 499 alone is increased with acute heart failure (no mention of chronic cardiomyopathy and no effect of estimated GFR, or of age).

If the problem was just of AMI, then we have to know what this brings to the table.  As it is the hs-troponins have yet to be shown to effectively not only increase the high sensitivity of the tests, but to decrease the confusion generated by the elevation.  The enormous improvement of a test that may be superior to the hs-ctn’s is for the patient with very indeterminiate shortness of breath, a nondefinitive ECG, and in a prodromal phase of AMI.  This happened in the past, and it may happen now, and it may account for many cases of silent MI that were found at autopsy.

Cited by
Plasma microRNAs serve as biomarkers of therapeutic efficacy and disease progression in hypertension-induced heart failure Eur J Heart Fail. 2013;0:hft018v1-hft018,
Circulating microRNAs as diagnostic biomarkers for cardiovascular diseases Am. J. Physiol. Heart Circ. Physiol.. 2012;303:H1085-H1095,

Circulation Editors’ Picks: Most Read Articles in Cardiovascular Genetics Circulation. 2012;126:e163-e169,
MicroRNAs in Patients on Chronic Hemodialysis (MINOS Study) CJASN. 2012;7:619-623,

Novel techniques and targets in cardiovascular microRNA research Cardiovasc Res. 2012;93:545-554,

Microparticles: major transport vehicles for distinct microRNAs in circulation Cardiovasc Res. 2012;93:633-644,

Profiling of circulating microRNAs: from single biomarkers to re-wired networks Cardiovasc Res. 2012;93:555-562,

Small but smart–microRNAs in the centre of inflammatory processes during cardiovascular diseases, the metabolic syndrome, and ageing   Cardiovasc Res. 2012;93:605-613,

Circulation: Heart Failure Editors’ Picks: Most Important Papers in Pathophysiology and Genetics Circ Heart Fail. 2012;5:e32-e49

Use of Circulating MicroRNAs to Diagnose Acute Myocardial Infarction   Clin. Chem. 2012;58:559-567,

Circulating microRNAs to identify human heart failure   Eur J Heart Fail. 2012;14:118-119,

Next Steps in Cardiovascular Disease Genomic Research–Sequencing, Epigenetics, and Transcriptomics  Clin. Chem. 2012;58:113-126,

Most Read in Cardiovascular Genetics on Biomarkers, Inherited Cardiomyopathies and Arrhythmias, Metabolomics, and Genomics Circ Cardiovasc Genet. 2011;4:e24-e30,

MicroRNA-126 modulates endothelial SDF-1 expression and mobilization of Sca-1+/Lin- progenitor cells in ischaemia  Cardiovasc Res. 2011;92:449-455,

The use of genomics for treatment is another matter, and has several factors, e.g., age, residual function after AMI, comorbidities

This is a lot of interesting work that opens as many questions as it answers. The observations are real, and they lead to questions relating to the heart and the circulation.  Maybe it will generate answers to very tough issues concerning hypertension, renal disease and the heart.  It is far too early to tell.  It appears that we are about to hear a cacophony of miR’s in a symphony on cardiac and circulatory diseases not be be pieced together soon. But we have many more tools at our disposal than we did when Karmen discovered and made a distinction between

  • Aspartate and Alanine aminotransferases in the late 1950s, followed in the 1960s by
  • Creatine phosphokinase, the
  • MB-isoenzyme of CK by Sobel, Shell and Kjeckshus,
  • isoenzyme-1 of lactate dehydrogenase, and later the
  • Troponins,

leading to the programs to “reduce the extent of infarct damage”.  Then came the

  • a- and b-type natriuretic peptides,

which are still not fully understood in their role in congestive heart failure and in renal disease.

One item strikes the imagination as a fruitful area of further study.   Genetic Determinants of Potassium Sensitivity and Hypertension.    Integrated Computational and Experimental Analysis of the Neuroendocrine Transcriptome in Genetic Hypertension Identifies Novel Control Points for the Cardiometabolic Syndrome

Essential hypertension, a common complex disease, displays substantial genetic influence. Contemporary methods to dissect the genetic basis of complex diseases such as the genomewide association study are powerful, yet a large gap exists betweens the fraction of population trait variance explained by such associations and total disease heritability.

The researchers

  • developed a novel, integrative method (combining animal models, transcriptomics, bioinformatics, molecular biology, and trait-extreme phenotypes)
  • to identify candidate genes for essential hypertension and the metabolic syndrome.

Method  …  transcriptome profiling on adrenal glands from blood pressure extreme mouse strains:

  1. the hypertensive BPH (blood pressure high) and
  2. hypotensive BPL (blood pressure low).

Results….   Microarray data clustering revealed

  • underexpression of intermediary metabolism transcripts in HIGH BLOOD PRESSURE.
  • The MITRA algorithm identified a conserved motif in the transcriptional regulatory regions of the underexpressed metabolic genes,
  • They decide that regulation through this motif contributed to the global underexpression.
  • Luciferase reporter assays demonstrated transcriptional activity of the motif through transcription factors
    • HOXA3,
    • SRY, and
    •  YY1.

They finally hypothesized that genetic variation at HOXA3, SRY, and YY1 might predict blood pressure and other metabolic syndrome traits in humans. Tagging variants for each locus were associated with

  • blood pressure in a human population blood pressure extreme sample with
  • the most extensive associations for YY1 tagging single nucleotide polymorphism rs11625658 on
  1. systolic blood pressure,
  2. diastolic blood pressure,
  3. body mass index, and
  4. fasting glucose.

Meta-analysis extended the YY1 results into 2 additional large population samples with significant effects preserved on diastolic blood pressure, body mass index, and fasting glucose.

It will take much more of this beautiful integrative work to open up our imagination as to what physiological processes are occurring.

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Lp(a) Gene Variant Association

Posted in Cardiovascular Pharmacogenomics, Genome Biology, Genomic Testing: Methodology for Diagnosis, International Global Work in Pharmaceutical, Pharmacotherapy of Cardiovascular Disease, tagged , , , , , , , , , on March 6, 2013| 5 Comments »

Lp(a) Gene Variant Association

Reporter: Larry H Bernstein, MD, FCAP

 

UPDATED on 2/20/2023

Universal Testing for Lp(a): What Are We Waiting For?

Dennis R. Leahy, MD

February 01, 2023

Lp(a) was associated with atherosclerotic cardiovascular disease (ASCVD), but whether an elevated blood level was a biomarker or a causal factor proved difficult to determine.

resurgent interest in molecular pathophysiology this past decade has clarified Lp(a)’s unique contribution to atherothrombotic disease and calcific aortic stenosis.

Lp(a) comprises an apoB particle bonded to an apo(a) particle. Apo(a) is complex and has a number of isoforms that can result in large heterogenicity in apo(a) size between, as well as within, individuals. This contributes to controversy about the ideal assay and whether Lp(a) levels should be expressed as mass (mg/dL) or number of particles (nmols/L). This should not, however, deter universal testing.

Universal Lp(a) testing would spotlight this pervasive and important risk factor that was referred to as the “horrible” cholesterol in a recent review.

To date, trials of an antisense oligonucleotide and a small interfering RNA molecule targeting hepatic LPA messenger RNA have confirmed that plasma Lp(a) levels can be significantly and safely lowered. If the ongoing Lp(a) HORIZON and OCEAN(a) phase 3 trials have positive outcomes in patients with known ASCVD, this would spawn a host of clinical trials to explore the possibilities of these therapies in primary prevention as well. These will require tens of thousands of enrollees, and universal testing would expand the pool of potential participants.

Recent data from the United Kingdom suggest that attainment of specific LDL-C levels may offset the risk for vascular events in those with high Lp(a) levels.

SOURCE

https://www.medscape.com/viewarticle/987221#vp_1

LDL-Lowering to Specific Targets May Offset Risk From High Lp(a)

https://www.medscape.com/viewarticle/974798

@@@@

Lp(a) Gene Variant Associated With Aortic Stenosis

Reported by Lisa Nainggolan Feb 06, 2013; GThanassoulis et al. NEJM http://www.theheart.org/article/1503525.do

People carrying this single nucleotide polymorphism (SNP) had a doubling of the risk of valve calcification on computer tomography (CT) compared with those without the variation. The same SNP has previously been identified as a risk factor for increased Lp(a) levels and coronary artery disease (CAD). Findings Could Reawaken Interest in Therapies Targeting Lp(a)

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A Single Nucleotide Polymorphism is a change o...

A Single Nucleotide Polymorphism is a change of a nucleotide at a single base-pair location on DNA. Created using Inkscape v0.45.1. (Photo credit: Wikipedia)

 

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Nanotechnology and Heart Disease

Posted in Bio Instrumentation in Experimental Life Sciences Research, Biomarkers & Medical Diagnostics, BioSimilars, Cardiac & Vascular Repair Tools Subsegment, Cardiovascular Pharmacogenomics, Cell Biology, Signaling & Cell Circuits, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Drug Delivery Platform Technology, Frontiers in Cardiology and Cardiovascular Disorders, Medical Devices R&D Investment, Nanotechnology for Drug Delivery, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Stents & Tools, Valves & Tools, tagged , , , , , , on March 4, 2013| 3 Comments »

Nanotechnology and Heart Disease

Author and Curator:  Tilda Barliya PhD

Cardiovascular disease is the most common cause of death worldwide and will become even more prevalent as the population ages. New therapeutic targets are being identified as a result of emerging insights into disease mechanisms, and new strategies are also being tested, possibly leading to new treatment options. Improving diagnosis is also crucial, because by detecting disease early, the focus could be shifted from treatment to prevention (1).

Mortality rates for cardiovascular disease have improved, but there are inequalities across the UK

The World Health Organization estimates that more than 17 million people died from cardiovascular diseases in 2008. In the U.S., about 785,000 people will have new heart attacks this year and 470,000 will suffer recurrent ones. While more patients are surviving such events, about two-thirds don’t make complete recoveries and are vulnerable to heart failure (2).

Heart and vascular disease is the number one killer in most industrialized nations, and costs countries billions in health care, and lost wages. Nanotechnology, biotechnology, robotics, and stem cells are reinvigorating the development of artificial components of the cardiovascular system. We’ve seen hearts grown from stem cells in labs, artificial mechanical hearts, companies spending millions to develop artificial blood, and now even artificial vascular tubes which act more like the real thing. Combined with upcoming advances in robotic and micro-surgery, medicine could be on the path to conquering its public enemy number one.

Nanotechnology offers several tools and advantages in cardiovascular science which are in the areas of diagnosis, imaging, and tissue engineering.

including:

  • treating defective heart valves
  • detecting and treat arterial plaque
  • understanding at a sub-cellular level how heart tissue functions in both healthy  and damaged organs, which can help researchers design better treatments

Examples:

Robert Langer, Omid Farokhzad and colleagues have developed nanoparticles that can cling to artery walls and slowly release medicine, an advance that potentially provides an alternative to drug-releasing stents in some patients with cardiovascular disease. The particles, dubbed “nanoburrs” because they are coated with tiny protein fragments that allow them to stick to target proteins, can be designed to release their drug payload over several days (3, 4). The nanoburrs are targeted to a specific structure, known as the basement membrane, which lines the arterial walls and is only exposed when those walls are damaged. Therefore, the nanoburrs could be used to deliver drugs to treat atherosclerosis and other inflammatory cardiovascular diseases. In the current study, the team used paclitaxel, a drug that inhibits cell division and helps prevent the growth of scar tissue that can clog arteries

Prof. Erkki Ruoslahti and other researchers from UC Santa Barbara have developed a nanoparticle that can attack plaque –– a major cause of cardiovascular disease (5).  These lipid-based micelles target the p32 receptors known to overexpress in plaques. To accomplish the research, the team induced atherosclerotic plaques in mice by keeping them on a high-fat diet. They then intravenously injected these mice with the micelles, which were allowed to circulate for three hours.

Clinical Trials:

“Nanotechnology creates artificial artery for clinical trials”

Researchers at London Royal Free Hospital are hoping to save limbs and lives with the creation of their new artificial artery. Unlike current artery replacements, this grafting substance was created using nanotechnology and can pulse with the natural movements of the body. That pulsing will allow the polymer tube to be used in very small grafts (<8mm), giving hope that damaged arteries which would normally lead to amputations or heart attacks can now be treated (6). The clinical study should have started by the end of 2010. No further information is currently available on this clinical trial.

The new artificial artery material was developed by Professors George Hamilton (vascular surgery) and Alexander Seifalian (nanotechnology and tissue repair). The substance is a polymer which has been embedded with different types of special molecules. Some of these molecules aid circulation, others encourage stem cells to coat its walls. That coating is very important and may allow the artificial tissue to bond better with the body and promote long term health. Most importantly though, the design of the artificial vascular tissue is resistant to clotting and can pulse.

Summary:

Research of heart disease is progressing on several levels simultaniously. It is believed that nanotechnology may offer several advantages in detecting and treating several heart conditions, however, they have yet to progressed into the clinical trials.

Quoting Dr. Tal Dvir: ” Many current experimental approaches to heart attack involve supplying growth factors, drugs, stem cells and other therapeutic agents to the scarred, dying tissue. Some of these compounds, such as periostin and neuregulin, have been shown in animal models to enhance heart regeneration and improve cardiac function. But the existing delivery approaches are all invasive, involving direct injections into the heart, catheter procedures, or surgical placement of implants that release the necessary factors.

The ultimate goal is to have the particles release compounds that promote regeneration. One approach is to release factors that attract the patient’s own stem cells, avoiding the need for tissue-engineered patches. But to date, no one’s gotten stem cells to differentiate efficiently into cardiomyocytes”

REFERENCES

1. http://www.nature.com/nature/supplements/insights/cardiovascular/index.html

2. Novel Cure for Ailing Hearts. http://online.wsj.com/article/SB10000872396390443537404577577002440205144.html

3. Chan JM., Zhang L., Tong R., Ghosh D., Gao W., Liao G., Yuet KP., Gray D., Rhee JW., Cheng J., Golomb G., Libby P, Langer R and Farokhzad OC. Spatiotemporal controlled delivery of nanoparticles to injured vasculature. Proc Natl Acad Sci U S A. 2010 Feb 2;107(5):2213-8.  http://www.pnas.org/content/107/5/2213.long

4. Chan JM., Rhee JW., Drum CL., Bronson RT., Golomb G., Langer R and Farokhzad OC. In vivo prevention of arterial restenosis with paclitaxel-encapsulated targeted lipid-polymeric nanoparticles. Proc Natl Acad Sci U S A. 2011 Nov 29;108(48):19347-52.

http://www.pnas.org/content/108/48/19347.long

5. Hamzah J., Kotamraju VR., Seo JW., Agemy L., Fogel V., Mahakian LM., Peters D., Roth L., Gagnon MK., Ferrara KW and Ruoslahti E. Specific penetration and accumulation of a homing peptide within atherosclerotic plaques of apolipoprotein E-deficient mice. Proc Natl Acad Sci U S A. 2011 Apr 26;108(17):7154-9. http://www.pnas.org/content/108/17/7154.long

6. Written By: : http://singularityhub.com/2010/01/05/nanotechnology-creates-artificial-artery-for-clinical-trials/

7. Ikaria® Commences Global Registration Trial for Bioabsorbable Cardiac Matrix. http://www.prnewswire.com/news-releases/ikaria-commences-global-registration-trial-for-bioabsorbable-cardiac-matrix-136581753.html.

8. Posted by: Prof. Lev-Ari :”Arteriogenesis and Cardiac Repair: Two Biomaterials – Injectable Thymosin beta4 and Myocardial Matrix Hydrogel” http://pharmaceuticalintelligence.com/2013/02/27/arteriogenesis-and-cardiac-repair-two-biomaterials-injectable-thymosin-beta4-and-myocardial-matrix-hydrogel/

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Cardiac Ca2+ Signaling: Transcriptional Control

Posted in Biological Networks, Cardiovascular Pharmacogenomics, Cell Biology, Disease Biology, Gene Regulation and Evolution, Genetics & Pharmaceutical, Genome Biology, Molecular Genetics & Pharmaceutical, Nutrition and Phytochemistry, Pharmaceutical Analytics, Pharmaceutical Industry Competitive Intelligence, Population Health Management, Signaling & Cell Circuits, Small Molecules in Development of Therapeutic Drugs, tagged , , , , , , , , , on March 2, 2013| 2 Comments »

Cardiac Ca2+ Signaling: Transcriptional Control

Reporter: Larry H Bernstein, MD, FCAP

The other side of cardiac Ca2+ signaling: transcriptional control

A Domínguez-Rodríguez, G Ruiz-Hurtado, Jean-Pierre Benitah and AM Gómez

  • Ca2+ is not only a key element in excitation-contraction coupling (EC coupling), but
  • it is also a pivotal second messenger in cardiac signal transduction,
  • being able to control processes such as
    • excitability,
    • metabolism, and
    • transcriptional regulation.

Front. Physio. 2012; 3:452.                 http://dx.doi.org/fphys.2012.00452/
http://www.fphys.com/The other side of cardiac Ca2+ signaling: transcriptional control

calcium release calmodulin

calcium release calmodulin

English: A rendition of the CaMKII holoenzyme ...

English: A rendition of the CaMKII holoenzyme in the (A) Closed and the (B) Open conformation (Photo credit: Wikipedia)

Related articles

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The Heart: Vasculature Protection – A Concept-based Pharmacological Therapy including THYMOSIN

Posted in Atherogenic Processes & Pathology, Bio Instrumentation in Experimental Life Sciences Research, Biomarkers & Medical Diagnostics, Cardiovascular Pharmacogenomics, Cell Biology, Signaling & Cell Circuits, Disease Biology, Small Molecules in Development of Therapeutic Drugs, FDA Regulatory Affairs, Frontiers in Cardiology and Cardiovascular Disorders, HTN, Human Immune System in Health and in Disease, Origins of Cardiovascular Disease, Personalized and Precision Medicine & Genomic Research, Pharmaceutical R&D Investment, Pharmacotherapy of Cardiovascular Disease, Population Health Management, Genetics & Pharmaceutical, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Stem Cells for Regenerative Medicine, Systemic Inflammatory Response Related Disorders, Technology Transfer: Biotech and Pharmaceutical, tagged , , , , , on February 28, 2013| 14 Comments »

Heart Vasculature – Regeneration and Protection of Coronary Artery Endothelium and Smooth Muscle: A Concept-based Pharmacological Therapy of a Combination Three Drug Regimen including THYMOSIN 

Author & Curator: Aviva Lev-Ari, PhD, RN

 

ABSTRACT

A concept-based original pharmacological therapy was developed for the research results presented in Cell by Wu, Fujiwara, Cibulsky et al. (2006), Moretti, Caron, Nakano, et al. (2006) and for the research results in Nature by Smart, Risebro, Melville, et al. (2007). We propose the following concept-based original pharmacological therapy design for Preoperative and Postoperative management of cardiac injury to heart tissue, smooth muscle, to aorta and coronary artery disease. This is a treatment for Coronary Vasculogenesis, Anti-hypertention (short-acting), Vascular Anti-inflammation (vasculitis), Neovascularization of ischemic tissue and release of adult epicardium from a quiescent state while restoring its pluripotency.

VIEW VIDEO

What are Induced Pluripotent Stem Cells? (iPS Cells)

 http://www.youtube.com/watch?v=i-QSurQWZo0

Lasker Lecture: Dr. Shinya Yamanaka, 2 of 3:

Induced Pluripotent Stem Cells? (iPS Cells)

http://www.youtube.com/watch?v=DQNoyDwCPzM

Multipotent Embryonic Isl1^+ Progenitor Cells Lead to Cardiac, Smooth Muscle, and Endothelial Cell Diversification

Alessandra A Moretti, Leslie L Caron, Atsushi A Nakano, Jason T JT Lam, Alexandra A Bernshausen,Yinhong Y Chen, Yibing Y Qyang, Lei L Bu, Mika M Sasaki, Silvia S Martin-Puig, Yunfu Y Sun, Sylvia M SM Evans, Karl-Ludwig KL Laugwitz, Kenneth R KR Chien
Cell 127(6):15 (2006), PMID 17123592

Cardiogenesis requires the generation of endothelial, cardiac, and smooth muscle cells, thought to arise from distinct embryonic precursors. We use genetic fate-mapping studies to document that isl1^+ precursors from the second heart field can generate each of these diverse cardiovascular cell types in vivo. Utilizing embryonic stem (ES) cells, we clonally amplified a cellular hierarchy of isl1^+ cardiovascular progenitors, which resemble the developmental precursors in the embryonic heart. The transcriptional signature of isl1^+/Nkx2.5^+/flk1^+ defines a multipotent cardiovascular progenitor, which can give rise to cells of all three lineages. These studies document a developmental paradigm for cardiogenesis, where muscle and endothelial lineage diversification arises from a single cell-level decision of a multipotent isl1^+ cardiovascular progenitor cell (MICP). The discovery of ES cell-derived MICPs suggests a strategy for cardiovascular tissue regeneration via their isolation, renewal, and directed differentiation into specific mature cardiac, pacemaker, smooth muscle, and endothelial cell types.

http://pubget.com/paper/17123592/Multipotent_Embryonic_Isl1___Progenitor_Cells_Lead_to_Cardiac__Smooth_Muscle__and_Endothelial_Cell_Diversification

 

Thymosin beta 4 (Tβ4)

is a highly conserved, 43-amino acid acidic peptide (pI 4.6) that was first isolated from bovine thymus tissue over 25 years ago. It is present in most tissues and cell lines and is found in high concentrations in blood platelets, neutrophils, macrophages, and other lymphoid tissues. Tβ4 has numerous physiological functions, the most prominent of which being the regulation of actin polymerization in mammalian nucleated cells and with subsequent effects on actin cytoskeletal organization, necessary for cell motility, organogenesis, and other important cellular events.

Recently,

  • Tβ4 was shown to be expressed in the developing heart and found to stimulate migration of cardiomyocytes and endothelial cells, promote survival of cardiomyocytes (Nature, 2004), and most recently
  • to play an essential role in all key stages of cardiac vessel development: vasculogenesis, angiogenesis, and arteriogenesis (Nature 2006).
  • These results suggest that Tβ4 may have significant therapeutic potential in humans to protect myocardium and promote cardiomyocyte survival in the acute stages of ischemic heart disease.

RegeneRx Biopharmaceuticals, Inc. is developing Tβ4 for the treatment of patients with acute myocardial infarction (AMI). Such efforts presented will include the formulation, development, and manufacture of a suitable drug product for use in the clinic, the performance of nonclinical pharmacology and toxicology studies, and the implementation of a phase 1 clinical protocol to assess the safety, tolerability, and the pharmacokinetics of Tβ4 in healthy volunteers.

http://onlinelibrary.wiley.com/doi/10.1196/annals.1415.051/abstract;jsessionid=BB7CC897572B7DDB60370EA64A81FC3F.d01t03?deniedAccessCustomisedMessage=&userIsAuthenticated=false

EXPLORATIONS with THYMOSIN beta4 for INDUCING ADULT EPICARDIAL PROGENETOR MOBILIZATION AND NEOVASCULARIZATION is presented in

Resident-cell-based Therapy in Human Ischaemic Heart Disease: Evolution in the PROMISE of Thymosin beta4 for Cardiac Repair

http://pharmaceuticalintelligence.com/2012/04/30/93/

EXPLORATIONS with THYMOSIN beta4 for INDUCTION of ARTERIOGENESIS, Prevention and repair of damaged cardiac tissue post MI and other CVD related research projects are presented in

Arteriogenesis and Cardiac Repair: Two Biomaterials – Injectable Thymosin beta4 and Myocardial Matrix Hydrogel

http://pharmaceuticalintelligence.com/2013/02/27/arteriogenesis-and-cardiac-repair-two-biomaterials-injectable-thymosin-beta4-and-myocardial-matrix-hydrogel/

Recent research results with THYMOSIN beta4 in use for Cardiovascular Disease

appeared in 2010:

Annals of the New York Academy of Sciences, May 2010 Volume 1194 Pages ix–xi, 1–230

http://onlinelibrary.wiley.com/doi/10.1111/nyas.2010.1194.issue-1/issuetoc

appeared in 2012:

  • Thymosins in Health and Disease II: 3rd International Symposium on The Emerging Clinical Applications of Tymosin beta 4 in Cardiovascular Disease

Annals of the New York Academy of Sciences, October 2012 Volume 1270 Pages vii-ix, 1–121.

http://onlinelibrary.wiley.com/doi/10.1111/nyas.2012.1270.issue-1/issuetoc

Allan L. Goldstein, Enrico Garaci, Editors, Thymosins in Cardiovascular Disease, November 2012, Wiley-Blackwell (paperback)

http://www.wiley.com/WileyCDA/WileyTitle/productCd-1573319104.html?cid=RSS_WILEY2_LIFEMED

Selected for this article are the abstracts of the following research projects, all were presented at the 2nd International Symposium, May 2010:

Thymosin β4: structure, function, and biological properties supporting current and future clinical applications

Published studies have described a number of physiological properties and cellular functions of thymosin β4 (Tβ4), the major G-actin-sequestering molecule in mammalian cells. Those activities include the promotion of cell migration, blood vessel formation, cell survival, stem cell differentiation, the modulation of cytokines, chemokines, and specific proteases, the upregulation of matrix molecules and gene expression, and the downregulation of a major nuclear transcription factor. Such properties have provided the scientific rationale for a number of ongoing and planned dermal, corneal, cardiac clinical trials evaluating the tissue protective, regenerative and repair potential of Tβ4, and direction for future clinical applications in the treatment of diseases of the central nervous system, lung inflammatory disease, and sepsis. A special emphasis is placed on the development of Tβ4 in the treatment of patients with ST elevation myocardial infarction in combination with percutaneous coronary intervention, pp.179-189, May 2010.

  

Thymosin β4 and cardiac repair

Hypoxic heart disease is a predominant cause of disability and death worldwide. As adult mammals are incapable of cardiac repair after infarction, the discovery of effective methods to achieve myocardial and vascular regeneration is crucial. Efforts to use stem cells to repopulate damaged tissue are currently limited by technical considerations and restricted cell potential. We discovered that the small, secreted peptide thymosin β4 (Tβ4) could be sufficiently used to inhibit myocardial cell death, stimulate vessel growth, and activate endogenous cardiac progenitors by reminding the adult heart on its embryonic program in vivo. The initiation of epicardial thickening accompanied by increase of myocardial and epicardial progenitors with or without infarction indicate that the reactivation process is independent of injury. Our results demonstrate Tβ4 to be the first known molecule able to initiate simultaneous myocardial and vascular regeneration after systemic administration in vivo. Given our findings, the utility of Tβ4 to heal cardiac injury may hold promise and warrant further investigation, pp. 87-96, May 2010.

 

Thymosin β4 facilitates epicardial neovascularization of the injured adult heart

Ischemic heart disease complicated by coronary artery occlusion causes myocardial infarction (MI), which is the major cause of morbidity and mortality in humans

http://www.who.int/cardiovascular_diseases/resources/atlas/en/index.html

After MI the human heart has an impaired capacity to regenerate and, despite the high prevalence of cardiovascular disease worldwide, there is currently only limited insight into how to stimulate repair of the injured adult heart from its component parts. Efficient cardiac regeneration requires the replacement of lost cardiomyocytes, formation of new coronary blood vessels, and appropriate modulation of inflammation to prevent maladaptive remodeling, fibrosis/scarring, and consequent cardiac dysfunction. Here we show that thymosin β4 (Tβ4) promotes new vasculature in both the intact and injured mammalian heart. We demonstrate that limited EPDC-derived endothelial-restricted neovascularization constitutes suboptimal “endogenous repair,” following injury, which is significantly augmented by Tβ4 to increase and stabilize the vascular plexus via collateral vessel growth. As such, we identify Tβ4 as a facilitator of cardiac neovascularization and highlight adult EPDCs as resident progenitors which, when instructed by Tβ4, have the capacity to sustain the myocardium after ischemic damage, pp. 97-104, May 2010.

 

Thymosin β4: a key factor for protective effects of eEPCs in acute and chronic ischemia

Acute myocardial infarction is still one of the leading causes of death in the industrial nations. Even after successful revascularization, myocardial ischemia results in a loss of cardiomyocytes and scar formation. Embryonic EPCs (eEPCs), retroinfused into the ischemic region of the pig heart, provided rapid paracrine benefit to acute and chronic ischemia in a PI-3K/Akt-dependent manner. In a model of acute myocardial ischemia, infarct size and loss of regional myocardial function decreased after eEPC application, unless cell pre-treatment with thymosin β4 shRNA was performed. Thymosin ß4 peptide retroinfusion mimicked the eEPC-derived improvement of infarct size and myocardial function. In chronic ischemia (rabbit model), eEPCs retroinfused into the ischemic hindlimb enhanced capillary density, collateral growth, and perfusion. Therapeutic neovascularization was absent when thymosin ß4 shRNA was introduced into eEPCs before application. In conclusion, eEPCs are capable of acute and chronic ischemia protection in a thymosin ß4 dependent manner, pp. 105-111, May 2010.

Clinical Study Data of Thymosin beta 4 Presented

Published on October 3, 2009 at 5:10 AM

REGENERX BIOPHARMACEUTICALS, INC. (NYSE Amex:RGN) today reported on several clinical studies with Thymosin beta 4 (Tβ4) presented the Second International Symposium on Thymosins in Health and Disease, in Catania, Italy. The following are synopses of the presentations:

Myocardial Development of RGN-352 (Injectable Tβ4 Peptide)

David Crockford, RegeneRx’s vice president for clinical and regulatory affairs presented an overview of the biological properties that support Tβ4’s near term and long term clinical applications. Mr. Crockford noted that special emphasis is being placed on the development of RGN-352 for the systemic (injectable) treatment of patients with ST-elevation myocardial infarction (STEMI) in combination with percutaneous coronary intervention, the current standard of care in most western countries for this common type of heart attack. The goal with RGN-352 is to prevent or repair continued damage to cardiac tissue post-heart attack, when such tissue around the damaged site remains at risk.

Dr. Dennis Ruff, vice president and medical director of ICON, and principal investigator, presented the most current results on the Phase I safety study with RGN-352 entitled, “A Randomized, Double-blind, Placebo-controlled, Dose-response Phase I Study of the Safety and Tolerability of the Intravenous Administration of Thymosin Beta 4 and its Pharmacokinetics After Single and Multiple Doses in Healthy Volunteers.” Dr. Ruff discussed key aspects of the study and concluded with, “There were no dose limiting or serious adverse events throughout the dosing period. Synthetic Tβ4 administered intravenously up to 1260 mg, and for up to 14 days, appears to be well tolerated with low incidence of adverse events and no evidence of serious adverse events.”

http://www.news-medical.net/news/20091003/Clinical-study-data-of-Thymosin-beta-4-presented.aspx

RegeneRx Receives Notice of Allowance from Chinese Patent Office for Treatment and Prevention of Heart Disease

RegeneRx Receives Notice of Allowance from Chinese Patent Office for Treatment and Prevention of Heart Disease

February 7, 2013 — Rockville, MD

RegeneRx Biopharmaceuticals, Inc. (OTC Bulletin Board: RGRX) (“the Company” or “RegeneRx”) today announced that it has received a Notice of Allowance of a Chinese patent application for uses of Thymosin beta 4 (TB4) for treating, preventing, inhibiting or reducing heart tissue deterioration, injury or damage in a subject with heart failure disease. Claims also include uses for restoring heart tissue in those subjects. The patent will expire July 26, 2026 http://www.regenerx.com/wt/page/pr_1360265259

Theoretical treatment protocol differential between the Preoperative which may be between 3 to 6 month, and the Postoperative which may prolong to one year.

Proposal for Preoperative Treatment – Three drug combination involves

  • Drug # 1: Thymosin fraction 5 (a sublingual composition)
  • Drug # 2: Indomethacin (Nonsteroidal anti-inflammatory drugs (NSAID))
  • Drug # 3: Clevidipine (blood pressure lowering drug, (no effect on heart rate))

 

Proposal for Postoperative Treatment – Three drug combination consists of

  • Drug # 1: Thymosin fraction 5 (a sublingual composition)
  • Drug # 4: ACEI (Captopril (50mg))
  • Drug # 5: Beta Blocker and Diuretic (Metoprolol and hydrochlorothiazide (50 mg/25 mg)) Lopressor HCT

Unprecedented novel paradigm development in the scientific understanding of the origin of

  • (a) myocardial cells
  • (b) smooth muscle cells
  • (c) endothelial cells
  • (d) pace maker cells and
  • (e) heart vasculature: aorta, pulmonary artery and coronary arteries, occurred in 2006.

In a seminal article in Cell, “Developmental Origin of a Bipotential Myocardial and Smooth Muscle Cell Precursor in the Mammalian Heart” Wu, et al., (2006), described their discovery as follows:

“Despite recent advances in delineating the mechanisms involved in cardiogenesis, cellular lineage specification remains incompletely understood.” To explore the relationship between developmental fate and potential.” They “isolated a cardiac-specific Nkx2.5+ cell population from the developing mouse embryo. The majority of these cells differentiated into cardiomyocytes and conduction system cells. Some, surprisingly, adopted a smooth muscle fate. To address the clonal origin of these lineages, we isolated Nkx2.5+ cells from in vitro differentiated murine embryonic stem cells and found ~28% of these cells expressed c-kit. These c-kit+ cells possessed the capacity for long-term in vitro expansion and differentiation into both cardiomyocytes and smooth muscle cells from a single cell.” They “confirmed these findings by isolating c-kit+Nkx2.5+ cells from mouse embryos and demonstrated their capacity for bipotential differentiation in vivo. Taken together, these results support the existence of a common precursor for cardiovascular lineages in the mammalian heart.”

Another breakthrough article in Cell, “Multipotent Embryonic Isl1+ Progenitor Cells Lead to Cardiac, Smooth Muscle, and Endothelial Cell Diversification” Moretti, et al., (2006) described their discovery as follows:

“Cardiogenesis requires the generation of endothelial, cardiac, and smooth muscle cells, thought to arise from distinct embryonic precursors.” They “use genetic fate-mapping studies to document that isl1+ precursors from the second heart field can generate each of these diverse cardiovascular cell types in vivo. Utilizing embryonic stem (ES) cells”, they “clonally amplified a cellular hierarchy of isl1+ cardiovascular progenitors, which resemble the developmental precursors in the embryonic heart. The transcriptional signature of isl1+/Nkx2.5+/flk1+ defines a multipotent cardiovascular progenitor, which can give rise to cells of all three lineages. These studies document a developmental paradigm for cardiogenesis, where muscle and endothelial lineage diversification arises from a single cell-level decision of a multipotent isl1+ cardiovascular progenitor cell (MICP). The discovery of ES cell-derived MICPs suggests a strategy for cardiovascular tissue regeneration via their isolation, renewal, and directed differentiation into specific mature cardiac, pacemaker, smooth muscle, and endothelial cell types.” (Moretti, et al., 2006).

Third scientific breakthrough was reported in Nature on the roles that Thymosin beta4 play in

  • (a) coronary vessel development
  • (b) induction of adult epicardial cell migration
  • (c) cardiomyocyte survival by vascularization which is dependent on Thymosin beta4 and
  • (d) identification of the pro-angiogenic tetrapeptide AcSDKP which is produced by endoproteinase activity of Thymosin beta4 (Smart, et al., 2007).

That new level of understanding has the potential to generate new pharmaco therapies to upregulate biological processes that underlie the function of the various compartments of the cardiovascular system, as new scientific explanations became available in 2006.

We have developed a methodology for discovery of concept-based original pharmacological therapy designs for combination of several drug regimens. We carry out two types of research strategy. Methodology Strategy Type One: we develop an original pharmacological therapy design specialized in addressing medical problems identified in targeted follow up studies on mortality and morbidity of cardiovascular patients. Methodology Strategy Type One is implemented in Lev-Ari & Abourjaily (2006a, 2006b, 2006c). We designed a specialized pharmaco therapy for the research results presented in NEJM, on “Circulating Endothelial Progenitor Cells and Cardiovascular Outcomes” (Werner, Kosiol, Schiegl, et al., 2005a) and the editorial interpretation of these research results by Rosenzweig  (2005). We proposed the following concept-based original pharmacological therapy design for Endogenous Augmentation of circulating Endothelial Progenitor Cells for Reduction of Risk for Macrovascular Cardiac Events.

 

Proposal of Treatment – Three drug combination

  • Inhibition of ET-1, ETA and ETA-ETB (Bosentan)
  • Induction of NO production and stimulation of eNOS (Nebivolol)
  • Stimulation of PPAR-gamma (substitute to Rosiglitazone)

Our Methodology Strategy Type Two involves discovery of concept-based original pharmacological therapy design for combination of several drug regimens for underlying biological processes discovered in the pursuit of basic researchers conducted in wet lab experiments by vascular biologists and molecular cardiologists. Here, we developed a concept-based original pharmacological therapy for the research results presented in Cell by Wu, Fujiwara, Cibulsky et al. (2006), Moretti, Caron, Nakano, et al. (2006) and for the research results in Nature by Smart, Risebro, Melville, et al. (2007). We propose the following concept-based original pharmacological therapy design for Preoperative and Postoperative management of cardiac injury to heart tissue, smooth muscle and to aorta and coronary artery disease. This is a treatment for Coronary Vasculogenesis, Anti-hypertention (short-acting), Vascular Anti-inflammation (vasculitis), Neovascularization of ischemic tissue and release of adult epicardium from a quiescent state and restoring its pluripotency.

 

Proposal for Preoperative Treatment – Three drug combination

  • Drug # 1:

Thymosin fraction 5 (a sublingual composition)

  • Drug # 2:

Indomethacin (Nonsteroidal anti-inflammatory drugs (NSAID))

  • Drug # 3:

Clevidipine (blood pressure lowering drug, no effect on heart rate)

Proposal for Postoperative Treatment – Three drugs combination

  • Drug # 1:

Thymosin fraction 5 (a sublingual composition)

  • Drug # 4:

ACEI (Captopril (50mg))

  • Drug # 5:

HCTBeta Blocker and Diuretic (Metoprolol and hydrochlorothiazide (50 mg/25 mg)) Lopressor

 

Thymosin beta4 Induces Adult Epicardial Progenitor Mobilization and Neovascularization

 

Smart et al. (2007) implicate Thymosine beta4 (Tb4) with the following functions: (a) Tb4 in regulating all three key stages of cardiac vessel development: coronary vasculogenesis, angiogenesis and arteriogenesis – collateral growth; (b) identify the adult epicardium as a potential source of vascular progenitors which, when stimulated by Tb4, migrate and differentiate into smooth muscle and endothelial cells; (c) the ability of Tb4 to promote coronary vascularization both during development and in the adult, enhances cardiomyocyte survival and contributes significantly towards Tb4-induced cardioprotection.

The reaction in the scientific community to these investigative results was most favorable.

“These results are very exciting because most humans suffering from ischemic cardiac events, either acutely or chronically, do not develop the collateral vessel growth necessary to preserve and restore heart tissue. If, in humans, we see the same effects as seen in mice, TB4 would be the first drug to prevent loss of (heart) muscle cells and restore blood flow in this manner and provide a new and much needed treatment modality for these patients,”

commented Deepak Srivastava, M.D., Professor and Director, Gladstone Institute of Cardiovascular Disease, University of California San Francisco, CA. Dr. Srivastava and his colleagues published the first paper on TB4’s effects on myocardial infarction in Nature in November 2004.

http://phx.corporate-ir.net/phoenix.zhtml?c=144396&p=irol-newsArticle&ID=932573&highlight=

VIEW VIDEO

http://www.youtube.com/watch?v=Vjj7LSuSMAo

 

Review of the Chemistry and the Mechanism of action supporting the process by which, N-acetyl-seryl-aspartyl-lysyl- proline (Ac-SDKP) stimulates endothelial cell differentiation from adult epicardium, is presented in

Resident-cell-based Therapy in Human Ischaemic Heart Disease: Evolution in the PROMISE of Thymosin beta4 for Cardiac Repair

http://pharmaceuticalintelligence.com/2012/04/30/93/

A Concept-based Pharmacologic Therapy of a Combined Three Drug Regimen for Regeneration and Protection of Coronary Artery Endothelium and Smooth Muscle.

This is a treatment for Coronary Vasculogenesis, Anti-hypertention (short-acting), Vascular Anti-inflammation (vasculitis), Neovascularization of ischemic tissue and release of adult epicardium from a quiescent state and restoring its pluripotency.

 

Preoperative Treatment – Three drugs

  • Drug # 1:
  • Thymosin fraction 5 (a sublingual composition)
  • Drug # 2:
  • Indomethacin (Nonsteroidal anti-inflammatory drugs (NSAID)) (25 mg PO bid)
  • Drug # 3:
  • Clevidipine (Blood pressure lowering drug, no effect on heart rate)

 

Postoperative Treatment – Three drugs

  • Drug # 1:
  • Thymosin fraction 5 (a sublingual composition)
  • Drug # 4:
  • ACEI (Captopril (50mg))
  • Drug # 5:
  • Beta Blocker and diuretic (Metoprolol and hydrochlorothiazide (50 mg/25 mg)) Lopressor HCT

Original Drug Therapy Combination Proposed

Drug # 1: Thymosin fraction 5

Drug # 2: Indomethacin

Drug # 3: Clevidipine

Drug # 1:

Sublingual compositions comprising Thymosin fraction 5

United States Patent:  6,733,791

http://www.pharmcast.com/Patents100/Yr2004/May2004/051104/6733791_Sublingual051104.htm

http://www.google.com/patents/US6733791

The compositions comprise a room temperature stable peptide or complex of peptides that may be administered in a dosage of between 0.0001 mg/ml or gm and 600 mg/ml or gm.

Thymosin beta4 is released from human blood platelets and attached by factor XIIIa (transglutaminase) to fibrin and collagen (Huff et al. 2002). They suggest that Thymosin beta4 cross-linking is mediated by factor XIIIa, a transglutaminase that is co-released from stimulated platelets. This provides a mechanism to increase the local concentration of Thymosin beta4 near sites of clots and tissue damage, where it may contribute to wound healing, angiogenesis and inflammatory responses (Al-Nedawi, et al., 2004). The beta-Thymosins constitute a family of highly conserved and extremely water-soluble 5 kDa polypeptides. Thymosin beta4 is the most abundant member; it is expressed in most cell types and is regarded as the main intracellular G-actin sequestering peptide. There is increasing evidence for extracellular functions of Thymosin beta4. For example, Thymosin beta4 increases the rate of attachment and spreading of endothelial cells on matrix components and stimulates the migration of human umbilical vein endothelial cells. They show that Thymosin beta4 can be cross-linked to proteins such as fibrin and collagen by tissue transglutaminase. Thymosin beta4 is not cross-linked to many other proteins and its cross-linking to fibrin is competed by another family member, Thymosin beta10 (Huff et al. 2002).

Rationale for selection of Sublingual compositions comprising Thymosin fraction 5

The actin binding motif of Thymosin beta4 is an essential site for its angiogenic activity (Philip, et al. (2003). Thymosin beta4 is presented in Smart, et al. (2007) in the Nature article as a single factor that can potentially couple myocardial and coronary vascular regeneration in failing mouse hearts. They have shown that cells in the heart’s outer layer can migrate deeper into a failing organ to carry out essential repairs. The migration of progenitor cells is controlled by the protein Thymosin beta 4, already known to help reduce muscle cell loss after a heart attack.

http://news.bbc.co.uk/2/hi/health/6143286.stm

The discovery opens up the possibility of using the protein to develop more effective treatments for heart disease. Previously it was thought that cells within the adult heart are in a state of permanent rest and that any progenitor cells that can contribute to heart tissue repair travel into the heart from the bone marrow. See 150 references on that perspective on cEPCs origin and roles, which was the scientific frontier on this topic, prior to the publication of Smart et al., (2007), in Lev-Ari & Abourjaily (2006a, 2006b, 2006c).

However, researchers at University College London have demonstrated that beneficial cells actually reside in the heart itself (Smart et al. (2007). This approach would bypass the risk of immune system rejection, a major problem with the use of stem cell transplants from another source. Allogenic rejection was the main reason for the selection of an endogenous augmentation method for cEPCs using drug therapy by Lev-Ari & Abourjaily  (2006a, 2006b, 2006c). Closer examination revealed that without the Thymosin beta 4 protein, the progenitor cells failed to move deeper into the heart and change the cells needed to build healthy blood vessels and sustain muscle tissue.

http://www.irishhealth.com/clin/cholesterol/newsstory.php?id=10581

Drug # 2:

Indomethacin

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for their anti-inflammatory effects and have been shown to have chemopreventive effects as well. NSAIDs inhibit cyclooxygenase (COX) activity to exert their anti-inflammatory effects, but it is not clear whether their antitumorigenic ability is through COX inhibition. Using subtractive hybridization, Jain et al. (2004) identified a novel member of the transforming growth factor- superfamily that has antitumorigenic activity from Indomethacin-treated HCT-116 human colorectal cancer cells. On further investigation of this library, they now report the identification of a new cDNA corresponding to the Thymosin beta-4 gene. Thymosin beta-4 is a small peptide that is known for its actin-sequestering function, and it is associated with the induction of angiogenesis, accelerated wound healing, and metastatic potential of tumor cells. However, only selective NSAIDs induce Thymosin beta-4 expression in a time- and concentration-dependent manner. For example,

Indomethacin and SC-560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole] induce Thymosin beta-4 expression whereas sulindac sulfide does not.

They show that selective NSAIDs induce actin cytoskeletal reorganization, a precursory step to many dynamic processes regulating growth and motility including tumorigenesis. This is the first report to link Thymosin beta-4 induction with NSAIDs. These data suggest that NSAIDs alter the expression of a diverse number of genes and provide new insights into the chemopreventive and biological activity of these drugs (Jain et al. 2004).

Rationale for Indomethacin selection

 

Inhibitor of prostaglandin synthesis. Inhibits cyclooxygenase (COX) 1 selective.

Suggested dosage: 25 mg PO bid.

Jain et al. (2004) report a link between Thymosin beta-4 induction with NSAIDs. We selected both drugs (drug classes) and anticipate strong synergistic therapeutic effects.

Drug # 3:

Clevidipine

Clevidipine is the first third-generation calcium channel blocker, Dr. Papadakos said. It has what he called an “ultrashort” clinically relevant half-life of about one minute and then is rapidly metabolized. The effect on blood pressure is seen within one to two minutes.

http://www.medpagetoday.com/MeetingCoverage/SCCM/tb/5091

Clevidipine is an investigational agent undergoing late-stage clinical development to evaluate its potential as an innovative, targeted, fast acting intravenous product under investigation for lowering blood pressure before, during and after surgery.

http://www.themedicinescompany.com/products_Clevidipine.shtml

The Medicines Company entered into agreements with AstraZeneca PLC in March of 2002 for the development, licensing and commercialization of Clevidipine. If approved, the product could be an excellent fit with The Medicines Company’s emerging acute cardiovascular care franchise, which is led by Angiomax® (bivalirudin), an anticoagulant approved in the U.S. and other countries for use during coronary angioplasty procedures. If Clevidipine passes further clinical hurdles — phase III trials are under way — the drug may form a useful addition to the medications available to physicians in the perioperative setting

Mechanism of Action

Clevidipine belongs to a well-known class of drugs called dihydropyridine calcium channel antagonists. In vitro studies demonstrated that Clevidipine acts by selectively relaxing the smooth muscle cells that line small arteries, resulting in widening of the artery opening and reducing blood pressure within the artery (Levy, Huraux, Nordlander, 1997, 345-358).

Phase III Clinical Trials

The Medicines Company is currently sponsoring a Phase III clinical program of five studies to evaluate safety and efficacy of Clevidipine:

Early Development

The Medicines Company’s development program for Clevidipine follows upon the data sets generated by AstraZeneca, which completed clinical pharmacology, dose-finding and efficacy studies in almost 300 patients or volunteers. In clinical studies, Clevidipine has shown to provide the desired blood pressure lowering effect without causing an increase in heart rate (Kotrly, et al. 1984). Further studies demonstrate that reductions in blood pressure are dose-dependent, are not associated with an increase in heart rate and cease rapidly after stopping Clevidipine infusions (Ericsson, et al., 2000), (Schwieler, et al., 1999). In clinical studies Clevidipine was rapidly metabolized independent of the liver and the kidneys, allowing rapid clearance of the drug from the bloodstream (Ericsson, et al., 1999a), (Ericsson, et al., 1999b). Therefore, the effects of Clevidipine are short-lived, which translates into a rapid cessation of its effect on reducing blood pressure.

The two efficacy studies are known as ESCAPE-1 and ESCAPE-2. The primary objective of these studies is to determine the efficacy of Clevidipine injection versus placebo in treating pre-operative (ESCAPE-1) and post-operative (ESCAPE-2) high blood pressure. Three safety studies are collectively known as ECLIPSE. The primary objective is to establish the safety of Clevidipine in the treatment of perioperative high blood pressure, as measured by a comparison of the incidences of death, stroke, myocardial infarction and renal dysfunction between the Clevidipine and comparative treatment groups. The comparative treatments are nitroglycerin, sodium nitroprusside and nicardipine.  The ECLIPSE trial randomized 589 patients at 40 centers in the U.S. to get either sodium nitroprusside or Clevidipine. Sodium nitroprusside was administered according to institutional practice; Clevidipine was begun at 2 mg/kg and doubled every 90 seconds until blood pressure was lowered. The primary endpoint was the difference in major clinical events — death, myocardial infarction, stroke, and renal dysfunction 30 days after surgery. The secondary endpoint was blood pressure control during the first 24 hours after surgery.

The study showed no significant differences in the elements of the primary endpoint, except for mortality, Dr. Papadakos said, where 1.7% of Clevidipine patients died, compared with 4.7 of those getting sodium nitroprusside.  The difference was statistically significant at P<0.05, but Dr. Papadakos characterized the improvement as “slight.” On the other hand, the drug did show an important difference in blood pressure control over the first 24 hours, he said:

  • Patients on Clevidipine spent an average of 4.37 minutes per hour outside the desired blood pressure range.
  • Sodium nitroprusside patients spent, on average, 10.5 minutes per hour outside the desired range.
  • The difference was statistically significant at P<0.003.

Dr. Papadakos concluded that Clevidipine is a new drug that is effective, safe, and easy to use. On 2/20/2007, Dr. Deutschman, who moderated the late-breaking session at which Dr. Papadakos spoke, said that a better comparison, would be intravenous nicardipine (Cardene IV), a second-generation calcium channel blocker that is also in wide use and is considered the standard of care. “We don’t know yet if this drug is going to be better than nicardipine,” he said.

http://www.medpagetoday.com/MeetingCoverage/SCCM/tb/5091

Rationale for Clevidipine selection

Clevidipine is an acute care product. Blood pressure management is a major component of care during the 13.4 million inpatient surgeries conducted in the U.S. each year. Blood pressure control, which is managed by an anesthesiologist, is often important in patients with both normal and high blood pressure undergoing surgery or other interventional procedures. Some of these patients require rapid, precise control of blood pressure to avoid compromising key organ function such as the heart, brain and kidney.

CONCLUSION 

This is the first study to design a novel combination drug treatment for Coronary Vasculogenesis, Anti-hypertention (short-acting), Vascular Anti-inflammation (vasculitis), Neovascularization of ischemic tissue and release of adult epicardium from a quiescent state and restoring its pluripotency. This treatment is based on the new three paradigms that were presented in Cell (2006) and Nature (2007). This combination drug therapy of three drugs, one in current use (Indomethacin), and two in clinical trials (Thymosin beta4 & Clevidipine), has not been proposed before. It represents an original concept drug combination design by Lev-Ari & Abourjaily (2007). This combination represents the cutting edge conceptualization of the field of treatment of cardiac injury based on a protein produced in the heart cells, Thymosin beta4, which function as a tissue and artery healer. Its upregulation by drug therapy will revolutionize cardiology and treatment for cardiovascular disease. The combination drug therapy consists of the following drugs:

  • Drug # 1:

Thymosin fraction 5 (a sublingual composition)

  • Drug # 2:

Indomethacin (Nonsteroidal anti-inflammatory drugs (NSAID)) (25 mg PO bid)

  • Drug # 3:

Clevidipine (Blood pressure lowering drug, (no effect on heart rate))

 

REFERENCES

Al-Nedawi, K.N.I., Malgorzata, C., Bednarek, R., Szemraj, J., Swiatkowska, M., Cierniewska-Cieslak, A., Wyczolkowska, J., Cierniewski, C.S. (2004, February) “Thymosin 4 induces the synthesis of plasminogen activator inhibitor 1 in cultured endothelial cells and increases its extracellular expression.” Blood, 103, (4), 1319-1324.

Ericsson, H., Fakt. C., Hoglund. L., et al. (1999a). “Pharmacokinetics and pharmacodynamics of Clevidipine in healthy volunteers after intravenous infusion.” Eur J Clin Pharm., 55 (1), 61-67.

Ericsson, H., Fakt, C., Jolin-Mellgard A., et al. (1999b). “Clinical and pharmacokinetic results with a new ultrashort-acting calcium antagonist, Clevidipine, following gradually increasing intravenous doses to healthy volunteers.” Br J Clin Pharm., 47 (5), 531-538.

Ericsson, H., Bredberg, U., Eriksson, U., et al. (2000). “Pharmacokinetics and arteriovenous differences in Clevidipine concentration following a short and a long-term intravenous infusion in healthy volunteers.” Anesthesiology, 92 (4), 993-1001.

Fleming, I. (2006). “Signaling by the Angiotensin-Converting Enzyme” Circulation Research, 98, 887.

Heart can carry out own repairs, 16.11.2006

Retrieved on 3/1/2007

http://www.medicalprogress.org/benefits/heartdis/news.cfm?news_id=478

Retrieved on 3/1/2007

http://news.bbc.co.uk/2/hi/health/6143286.stm

Heart may be able to repair itself

Retrieved on 3/1/2007

http://www.irishhealth.com/clin/cholesterol/newsstory.php?id=10581

Huff, T., Otto, A., Muller, C.S.G., Meier, M., Hannappel, E. (2002). “Thymosin ß4 is released from human blood platelets and attached by factor XIIIa (transglutaminase) to fibrin and collagen.”The FASEB Journal, 16, 691-696.

Jain, A.K., Moore, S.M., Yamaguchi, K., Eling, T.E., Baek, S.J. (2004, August). “Selective Nonsteroidal Anti-Inflammatory Drugs Induce Thymosin beta-4 and Alter Actin Cytoskeletal Organization in Human Colorectal Cancer Cells.” Journal of Pharmacology and Experimental Therapeutics, 311 (3) 885-891.

Kotrly, K. J., Ebert, T. J., Vucins, E. et al. (1984). “Baroreceptor reflex control of heart rate during isoflurane anesthesia in humans.” Anesthesiology,  60, 173-179.

Lev-Ari, A. & Abourjaily, P. (2006a) “An Investigation of the Potential of circulating Endothelial Progenitor Cells (cEPC) as a Therapeutic Target for Pharmacologic Therapy Design for Cardiovascular Risk Reduction.” Part I: Macrovascular Disease – Therapeutic Potential of cEPCs – Reduction methods for CV risk. Unpublished manuscript.

Lev-Ari, A. & Abourjaily, P. (2006b) “An Investigation of the Potential of circulating Endothelial Progenitor Cells (cEPC) as a Therapeutic Target for Pharmacologic Therapy Design for Cardiovascular Risk Reduction.” Part II: Therapeutic Strategy for cEPCs Endogenous Augmentation: A Concept-based Treatment Protocol for a Combined Three Drug Regimen. Unpublished manuscript.

Lev-Ari, A. & Abourjaily, P. (2006c) “An Investigation of the Potential of circulating Endothelial Progenitor Cells (cEPC) as a Therapeutic Target for Pharmacological Therapy Design for Cardiovascular Risk Reduction.” Part III: Biomarker for Therapeutic Targets of Cardiovascular Risk Reduction by cEPCs Endogenous Augmentation using New Combination Drug Therapy of Three Drug Classes and Several Drug Indications. A Theoretical Design for Quantification of the Endogenous EPCs Augmentation for Differential Level of CV Risk Reduction and Diagnostic Device Design for Drug Delivery. Unpublished manuscript.

Lev-Ari, A. & Abourjaily, P. (2007). Heart Vasculature – Regeneration and Protection of Coronary Artery Endothelium and Smooth Muscle: A Concept-based Pharmacological Therapy of a Combined Three Drug Regimen. Unpublished manuscript.

Levy, J. H., Huraux, C., Nordlander, M. (1997). “Treatment of perioperative hypertension.” In: Epstein M, Ed. Chapter in Calcium Antagonists in Clinical Medicine. Philadelphiea: Hanely & Belfus, pp. 345-358.

Liu, J-M, Lawrence, F., Kovacevic, M., Bignon, J., Papadimitriou, E., Lallemand, J-Y., Katsoris, P., Potier, P., Fromes, Y., Wdzieczak-Bakala, J. (2003, April) “The tetrapeptide AcSDKP, an inhibitor of primitive hematopoietic cell proliferation, induces angiogenesis in vitro and in vivo.” Blood, 101 (8), 3014-3020

Moretti, A., Caron, L., Nakano, A., Lam, J.T., Bernshausen, A., Chen, Y., Qyang, Y., Bu, L., Sasaki, M., Martin-Puig, S., Sun, Y., Evans, S.M., Laugwitz, K-L, Chien, K.R. (2006, December) “Multipotent Embryonic Isl1+ Progenitor Cells Lead to Cardiac, Smooth Muscle, and Endothelial Cell Diversification.” Cell, 127, 1151-1165.

Protein Discovered That Can Tell Human Heart to Heal Itself

Retrieved 3/1/2007

http://www.cathlabdigest.com/displaynews.cfm?newsid=1122065

Philp D, Huff T, Gho YS, Hannappel E, Kleinman HK. (2003). “The actin binding site on Thymosin beta4 promotes angiogenesis.” FASEB Journal, published on line 9/18/2003.

Retrieved 3/1/2007

http://www.fasebj.org/cgi/reprint/03-0121fjev1.pdf

Putting the art in heart research, 15 February 2007

Retrieved on 3/1/2007

http://www.ich.ucl.ac.uk/pressoffice/pressrelease_00498

Rosenzweig A., (2005). Circulating Endothelial Progenitors – Cells as Biomarkers. NEJM, 353 (10), 1055-1057.

Schwieler, J.H., Ericsson, H., Lofdahl, P., et al. (1999). “Circulatory effects and pharmacology of Clevidipine, a novel ultra short acting and vascular selective calcium antagonist, in hypertensive humans.” J Cardiovasc Pharmacology, 34 (2), 268-274.

Smart, N., Risebro, C.A., Melville, A.D., Moses, K., Schwartz, R.J., Chien, K.R., Riley, P.R. (2007, January) “Thymosin Beta4 induces adult epicardial progenitor mobilization and neovascularization.” Nature, 445, 177-182.

 

Sublingual compositions comprising Thymosin fraction 5 and methods for administration

Retrieved 3/1/2007

http://www.pharmcast.com/Patents100/Yr2004/May2004/051104/6733791_Sublingual051104.htm

 

TMSB4X  Thymosin, beta 4, X-linked

Retrieved on 3/1/2007

http://www.ihop-net.org/UniPub/iHOP/gs/92756.html

Waeckel, L., Jérôme Bignon, J., Jian-Miao Liu, J-M., Markovits, D., Ebrahimian, T.G., Vilar, J., Mees, B., Blanc-Brude, O., Barateau, V., Sophie Le ricousse-Roussanne. S., Duriez, M. Tobelem, G.,  Wdzieczak-Bakala, J., Bernard I Lévy, B.I., Silvestre, J-S. (2006) “Tetrapeptide AcSDKP Induces Postischemic Neovascularization Through Monocyte Chemoattractant Protein-1 Signaling.” Arteriosclerosis, Thrombosis, and Vascular Biology, 26, 773

Wang, D., Oscar A. Carretero, O.A.,Yang, X-Y., Rhaleb, N-E., Liu, Y-H., Liao, T-D., Yang, X-P. (2004). “N-acetyl-seryl-aspartyl-lysyl-proline stimulates angiogenesis in vitro and in vivo.” Am J Physiol Heart Circ Physiol., 287, H2099-H2105.

Werner N, Junk S, Laufs L, Link A, Walenta K, Bohm M, Nickenig G., (2003).  Intravenous transfusion of endothelial progenitor cells reduces neointima formation after vascular injury. Circ Res., 93, e17– e24.

Werner N, Kosiol S, Schiegl T, Ahlers P, Walenta K, Link A, Böhm M, Nickenig G. (2005a). Circulating Endothelial Progenitor Cells and Cardiovascular Outcomes, NEJM, 353, 999-1007

Werner, N. & Nickenig, G. (2005b). Authors Reply to Correspondence to the Editor on Circulating Endothelial Progenitor Cells. NEJM, 353 (24), 2613-2616

Wu, S.M., Fujiwara, Y., Cibulsky, S.M., Clapham, D.E., Lien, C., Schultheiss, T.M., Orkin, S.H. (2006, December). “Developmental Origin of a Bipotential Myocardial and Smooth Muscle Cell Precursor in the Mammalian Heart.” Cell, 127, 1137-1150.

Other related articles on this Open Access Online Scientific Journal, include the following:

Saha, S. (2012b) Innovations in Bio instrumentation for Measurement of Circulating Progenetor Endothelial Cells in Human Blood.
http://pharmaceuticalintelligence.com/2012/07/08/innovations-in-bio-instrumentation-for-measurement-of-circulating-progenitor-endothelial-cells-in-human-blood/

 

Saha, S. (2012c) Endothelial Differentiation and Morphogenesis of Cardiac Precursor
http://pharmaceuticalintelligence.com/2012/07/17/endothelial-differentiation-and-morphogenesis-of-cardiac-precursors/

Saha, S. (2012e). Human Embryonic-Derived Cardiac Progenitor Cells for Myocardial Repair

http://pharmaceuticalintelligence.com/2012/08/01/human-embryonic-derived-cardiac-progenitor-cells-for-myocardial-repair/

Lev-Ari, A. 12/29/2012. Coronary artery disease in symptomatic patients referred for coronary angiography: Predicted by Serum Protein Profiles

http://pharmaceuticalintelligence.com/2012/12/29/coronary-artery-disease-in-symptomatic-patients-referred-for-coronary-angiography-predicted-by-serum-protein-profiles/

 

Bernstein, HL and Lev-Ari, A. 11/28/2012. Special Considerations in Blood Lipoproteins, Viscosity, Assessment and Treatment

http://pharmaceuticalintelligence.com/2012/11/28/special-considerations-in-blood-lipoproteins-viscosity-assessment-and-treatment/

 

Lev-Ari, A. 11/13/2012 Peroxisome proliferator-activated receptor (PPAR-gamma) Receptors Activation: PPARγ transrepression for Angiogenesis in Cardiovascular Disease and PPARγ transactivation for Treatment of Diabetes

http://pharmaceuticalintelligence.com/2012/11/13/peroxisome-proliferator-activated-receptor-ppar-gamma-receptors-activation-pparγ-transrepression-for-angiogenesis-in-cardiovascular-disease-and-pparγ-transactivation-for-treatment-of-dia/

 

Lev-Ari, A. 10/19/2012 Clinical Trials Results for Endothelin System: Pathophysiological role in Chronic Heart Failure, Acute Coronary Syndromes and MI – Marker of Disease Severity or Genetic Determination?

http://pharmaceuticalintelligence.com/2012/10/19/clinical-trials-results-for-endothelin-system-pathophysiological-role-in-chronic-heart-failure-acute-coronary-syndromes-and-mi-marker-of-disease-severity-or-genetic-determination/

 

Lev-Ari, A. 10/4/2012 Endothelin Receptors in Cardiovascular Diseases: The Role of eNOS Stimulation

http://pharmaceuticalintelligence.com/2012/10/04/endothelin-receptors-in-cardiovascular-diseases-the-role-of-enos-stimulation/

 

Lev-Ari, A. 10/4/2012 Inhibition of ET-1, ETA and ETA-ETB, Induction of NO production, stimulation of eNOS and Treatment Regime with PPAR-gamma agonists (TZD): cEPCs Endogenous Augmentation for Cardiovascular Risk Reduction – A Bibliography

http://pharmaceuticalintelligence.com/2012/10/04/inhibition-of-et-1-eta-and-eta-etb-induction-of-no-production-and-stimulation-of-enos-and-treatment-regime-with-ppar-gamma-agonists-tzd-cepcs-endogenous-augmentation-for-cardiovascular-risk-reduc/

 

Lev-Ari, A. 8/28/2012 Cardiovascular Outcomes: Function of circulating Endothelial Progenitor Cells (cEPCs): Exploring Pharmaco-therapy targeted at Endogenous Augmentation of cEPCs

http://pharmaceuticalintelligence.com/2012/08/28/cardiovascular-outcomes-function-of-circulating-endothelial-progenitor-cells-cepcs-exploring-pharmaco-therapy-targeted-at-endogenous-augmentation-of-cepcs/

 

Lev-Ari, A. 8/27/2012 Endothelial Dysfunction, Diminished Availability of cEPCs, Increasing CVD Risk for Macrovascular Disease – Therapeutic Potential of cEPCs

http://pharmaceuticalintelligence.com/2012/08/27/endothelial-dysfunction-diminished-availability-of-cepcs-increasing-cvd-risk-for-macrovascular-disease-therapeutic-potential-of-cepcs/

 

Lev-Ari, A. 8/24/2012 Vascular Medicine and Biology: CLASSIFICATION OF FAST ACTING THERAPY FOR PATIENTS AT HIGH RISK FOR MACROVASCULAR EVENTS Macrovascular Disease – Therapeutic Potential of cEPCs

http://pharmaceuticalintelligence.com/2012/08/24/vascular-medicine-and-biology-classification-of-fast-acting-therapy-for-patients-at-high-risk-for-macrovascular-events-macrovascular-disease-therapeutic-potential-of-cepcs/

 

Lev-Ari, A. 7/30/2012 Biosimilars: Intellectual Property Creation and Protection by Pioneer and by Biosimilar Manufacturers

http://pharmaceuticalintelligence.com/2012/07/30/biosimilars-intellectual-property-creation-and-protection-by-pioneer-and-by-biosimilar-manufacturers/

 

Lev-Ari, A. 7/29/2012 Biosimilars: Financials 2012 vs. 2008

http://pharmaceuticalintelligence.com/2012/07/30/biosimilars-financials-2012-vs-2008/

 

Lev-Ari, A. 7/29/2012 Biosimilars: CMC Issues and Regulatory Requirements

http://pharmaceuticalintelligence.com/2012/07/29/biosimilars-cmc-issues-and-regulatory-requirements/

 

Lev-Ari, A. 7/19/2012 Cardiovascular Disease (CVD) and the Role of agent alternatives in endothelial Nitric Oxide Synthase (eNOS) Activation and Nitric Oxide Production

http://pharmaceuticalintelligence.com/2012/07/19/cardiovascular-disease-cvd-and-the-role-of-agent-alternatives-in-endothelial-nitric-oxide-synthase-enos-activation-and-nitric-oxide-production/

 

Lev-Ari, A. 4/30/2012 Resident-cell-based Therapy in Human Ischaemic Heart Disease: Evolution in the PROMISE of Thymosin beta4 for Cardiac Repair

http://pharmaceuticalintelligence.com/2012/04/30/93/

Lev-Ari, A. 5/29/2012 Triple Antihypertensive Combination Therapy Significantly Lowers Blood Pressure in Hard-to-Treat Patients with Hypertension and Diabetes

http://pharmaceuticalintelligence.com/2012/05/29/445/

 

Lev-Ari, A. 7/2/2012 Macrovascular Disease – Therapeutic Potential of cEPCs: Reduction Methods for CV Risk

http://pharmaceuticalintelligence.com/2012/07/02/macrovascular-disease-therapeutic-potential-of-cepcs-reduction-methods-for-cv-risk/

 

Lev-Ari, A. 7/9/2012 Mitochondria Dysfunction and Cardiovascular Disease – Mitochondria: More than just the “powerhouse of the cell”

http://pharmaceuticalintelligence.com/2012/07/09/mitochondria-more-than-just-the-powerhouse-of-the-cell/

 

Lev-Ari, A. 7/16/2012 Bystolic’s generic Nebivolol – positive effect on circulating Endothelial Proginetor Cells endogenous augmentation

http://pharmaceuticalintelligence.com/2012/07/16/bystolics-generic-nebivolol-positive-effect-on-circulating-endothilial-progrnetor-cells-endogenous-augmentation/

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Personalized Cardiovascular Genetic Medicine at Partners HealthCare and Harvard Medical School

Posted in Atherogenic Processes & Pathology, Biological Networks, Biomarkers & Medical Diagnostics, Cardiomyopathy, Cardiovascular Pharmacogenomics, Cardiovascular Research, Cell Biology, Chemical Biology and its relations to Metabolic Disease, Chemical Genetics, Computational Biology/Systems and Bioinformatics, Congenital Heart Disease, Electrophysiology, Frontiers in Cardiology and Cardiovascular Disorders, Genome Biology, Genomic Testing: Methodology for Diagnosis, HTN, Medical and Population Genetics, Molecular Genetics & Pharmaceutical, Myocardial Metabolism, Origins of Cardiovascular Disease, Personalized and Precision Medicine & Genomic Research, Pharmacogenomics, Pharmacotherapy of Cardiovascular Disease, Population Health Management, Proteomics, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Technology Transfer: Biotech and Pharmaceutical, Translational Research, Translational Science, tagged , , , , , , , , , on February 25, 2013| 3 Comments »

Personalized Cardiovascular Genetic Medicine at Partners HealthCare and Harvard Medical School

Curator: Aviva Lev-Ari, PhD, RN

UPDATED on 5/4/2015

Goes to Clinic @MGH: Clinically validated versions of Exome Sequencing and Analysis using Broad-developed methods like Hybrid Capture, the Genome Analysis Toolkit (GATK), and MuTect

http://pharmaceuticalintelligence.com/2015/05/04/goes-to-clinic-mgh-clinically-validated-versions-of-exome-sequencing-and-analysis-using-broad-developed-methods-like-hybrid-capture-the-genome-analysis-toolkit-gatk-and-mutect/

Center for Personalized Genetic Medicine, Partners HealthCare and Harvard Medical School

The Partners HealthCare Center for Personalized Genetic Medicine offers technologies and technical support for the research activities of Partners investigators. Our objective is to help investigators advance their research programs and to provide the highest quality service, technical expertise, and leading technologies for genomics research. Our goal is to broaden the access to these technologies while offering the best customer service in the most cost conscious and time efficient manner possible.

We are organized into four principal service areas:

  • sequence analysis,
  • genotyping,
  • expression analysis, and
  • bioprocessing/sample management

Our platforms include next generation sequencing with Illumina HiSeq2000 and GA ii analyzers as well as Sanger sequencing using ABI 3730 XL sequence analyzers. Targeted custom genotyping is offered using Sequenom and Illumina GoldenGate panels as well as GWAS scale projects using Illumina Infinium and DNA methylation analysis using Illumina bead arrays. Expression analysis is available with capabilities for processing total RNA on either Affymetrix or Illumina arrays.

Through services from our BioSample Services Facility (BSF) and Partners Biorepository for Medical Discovery (PBMD) teams we provide a research platform for handling samples in a standardized manner to provide consistency from sample to sample. The BSF is able to assist investigators to configure projects utilizing your own samples or coupled with the PCPGM-PBMD we are able to support the integration of cohorts of samples selected from the PBMD into analysis on our genomics platforms.

DNA Sequencing

The DNA Sequencing Group at the Partners HealthCare Center for Personalized Genetic Medicine has a strong history of producing high quality, dependable, and informative results for collaborators and clients. The DNA Sequencing Group participated in the Human Genome Project, building the STS-Based BAC map for Human Chromosome 12, and providing Chromosome 12 tiling path clones to the Baylor Human Genome Sequencing Center for sequencing.

The group sequenced 113 BACs for the Mouse Genome Project, contributing 24 megabases of finished mouse sequences to the published Mouse Genome, as well as providing draft sequences for unique strains of several bacterial genomes, including Pseudomonas aeruginosa, and Vibrio cholerae. More recently, the group participated in identifying mutations linked to numerous diseases, either in collaborations or by providing client laboratories with full service resequencing and analysis.

Services by Project Goals

Mutation Identification via Resequencing

This facility provides full-service resequencing of regions of interest in one or more genomic DNAs, including the following:

  • Discussion of the scope of the project and a cost quote
  • Identification of genes in the region of interest as needed, with the Investigator
  • Primer design using our automated system, to amplify desired regions
  • Primer ordering
  • QC of the primers on DNA standards, if required
  • PCR amplification of DNA provided by Investigator
  • PCR clean-up
  • Sequencing reactions
  • Sequencing reaction clean-up
  • Sequence application to the ABI 3730 XL Analyzer
  • Chromatograms are made available to Investigator over web (GIGPAD)
  • Data assembly and analysis using Phred Phrap and PolyPhred
  • One round of repeats and redesign if necessary
  • Report of variations found throughout sequence
  • Trouble shooting for 100% coverage if desired
Research Services
  • Fee-for-service sequencing
  • Fragment analysis / genotyping (Microsatellite Instability)
Technology Development
  • New technology testing and development
  • Collaborative Protocol development
  • Beta-test site for instrumentation and software
Clinical Diagnosis
  • Diagnostic test development
  • Sequencing for clinical diagnostics group
Genomic Sequencing Projects
  • Human
  • Rodent
  • Bacteria

http://pcpgm.partners.org/research-services/sequencing

Advancing Translational Genomics through Personalized Medicine Projects

The mission of the Partners HealthCare Center for Personalized Genetic Medicine (PCPGM) is to utilize genetics and genomics to promote and implement personalized medicine in caring for patients throughout the Partners HealthCare system and in health care nationally and globally.

The Personalized Medicine Project program was developed to support the clinical research efforts of junior Partners HealthCare investigators for translational genetics and genomic projects to advance personalized medicine.  The goal of this program is to identify biological markers that can be used as potential predictive tests.  This will be accomplished by:

  • Leveraging the Partners HealthCare Research Patient Data Registry (RPDR) and the Partners Biorepository for Medical Discovery (PBMD), centralized locations where Partners HealthCare patient data and/or samples are stored.
  • Identifying novel biological markers or new uses for existing markers.
  • Focusing on tests that could:
    • improve diagnostic sensitivity or specificity;
    • further stratify patient groups with a given diagnosis;
    • predict improved clinical outcomes; or
    • assist with selection of therapies or methods to manage disease.

http://pcpgm.partners.org/biorepository/pmprojectsrfp

Harvard Medical School Genetics Training Program

The Harvard Medical School (HMS) Genetics Training Program is one of the oldest and largest programs in the country. It was founded by Drs. John Littlefield at the Massachusetts General Hospital and Park Gerald at Children’s Hospital Boston in the early 1970’s. The program has trained scientists and clinicians who have become leaders in academic genetics, and has supported investigators who have made major contributions to the clinical practice of genetics and genetics research.

The HMS Genetics Training Program is accredited by the ABMG in all areas of training – Clinical Genetics, Biochemical Genetics, Cytogenetics, and Molecular Genetics. This provides an opportunity for our trainees to become active candidates for board certification in a discipline(s) of medical genetics in addition to receiving laboratory training. The training laboratories and clinics of the program are centered at HMS and its affiliated institutions including Brigham and Women’s Hospital (BWH), the HMS Department of Genetics, Beth Israel Deaconess Medical Center (BIDMC), Children’s Hospital Boston (CHB), Dana Farber Cancer Institute (DFCI), and Massachusetts General Hospital (MGH). The HMS Genetics Training Program provides trainees the opportunity to take advantage of the extraordinarily rich academic environment offered at HMS and its affiliated institutions as well as the greater Boston scientific community.

Cardiovascular Research Center @MGH

The Cardiovascular Research Center was founded in 1990, and occupies over 30,000 sq. ft. of laboratory space in both the Charlestown Navy Yard and the Richard B. Simches Research Building. Dr. Mark Fishman, now president of the Novartis Institutes for Biomedical Research, directed the Center from 1990 until 2002. From 2002-2005, Dr. Kenneth Bloch served as Interim Director and then in June 2005, the Massachusetts General Hospital welcomed Dr. Kenneth Chien as the new scientific director of the Cardiovascular Research Center. Prior to his MGH appointments, Dr. Chien directed the Institute for Molecular Medicine at the University of California at San Diego. An internationally recognized biologist specializing in cardiovascular science, he is a true pioneer in developing new therapeutic strategies to prevent the onset and progression of heart failure. Dr. Chien served as director until 2012.

Cardiovascular Research Center investigators have made many groundbreaking discoveries. Among these include:

• first identification of progenitor cells in the heart
• cloning of the first vertebrate cell death genes
• knocking out the genes that produce nitric oxide (NO), showing the importance of this molecule to atherosclerosis and stroke
• clinical use of NO to treat patients with pulmonary hypertension
• development of gene and cell transfer approaches to treat heart failure
• performance of the first large-scale genetic screen in a vertebrate (the zebrafish)
• identification of genes critical to cardiac pacemaking, rhythm, contractile function, and normal heart patterning
• discovery of a new methylase gene responsible for altering DNA structure during an individual’s lifetime

The Cardiovascular Research Center has taken great pride in the training of scientists with MDs and/or PhDs, as well as graduate students from a variety of Boston area institutions.

The Cardiovascular Research Center has two locations, one in the Charlestown Navy Yard and the other on the main campus’s Charles River Plaza complex in the Richard Simches Research Center.

Both the Simches and Navy Yard sites offer state of the art facilities, including tissue culture rooms, warm and cold rooms, histology rooms, autoclave facilities, hot labs, scope rooms and conference rooms. The Navy Yard lab has a topnotch zebrafish facility that is utilized by many scientists both inside and outside the Center, and a transgenic mouse core for both knock-ins and knock-outs. The Navy Yard facilities also contain echocardiogram equipment, specialized microscopes equipped with video capability for making movies, as well as a confocal microscope available to the Center researchers. The Simches lab houses the CVRC Stem Cell Biology + Therapy program, including a dedicated facility for human ES cell based technology, run by Dr. Chad Cowan, and future plans for high throughput screening facility to allow chemical screening in ESX cell based systems. Other cores available to researchers include a Cell Sorting and Flow Cytometry lab and a DNA sequencing core.

The Cardiology Laboratory for Integrative Physiology & Imaging lab is dedicated to large animal studies. An in house interventional cardiologist specializing in large animals performs the surgeries. In addition there are technicians that assist in the daily operations of the lab and can assist in experiment design and project implementation. This lab specializes in large animal imaging, CAT scans and catheter base manipulations. There is also an MRI imaging facility housed in the lab.

http://www2.massgeneral.org/cvrc/about.html

Genomics and Cardiovascular Medicine @MGH

Translational Medicine: Genomics and Proteomics @MGH
The goal of the Translational Medicine Program is to harness the rich clinical cardiovascular population at the Massachusetts General Hospital to identify and validate novel genomic determinants of cardiovascular disease. Our goal is not to capture the entire cohort of cardiovascular patients presenting to Massachusetts General Hospital, but rather to focus our efforts on extremely well-phenotyped human models that are unique to cardiovascular disease. Of particular interest are “perturbational” studies in humans (e.g., cardiac exercise testing) that elicit robust phenotypes in affected individuals to serve as the springboard for analyses that span from genomics to proteomics and biochemical profiling. The Translational Medicine Program will involve a multidisciplinary group of investigators who contribute expertise in cardiovascular basic science, clinical cardiology, genetic/genomic epidemiology, bioinformatics, imaging, pathology, as well as clinical chemistry and mass spectrometry. While the Program in Translational Medicine will be physically located at the Massachusetts General Hospital Main Campus, the effort will leverage ongoing interdisciplinary collaborations with investigators at the Framingham Heart Study, the Broad Institute of M.I.T., Harvard University, and Harvard Medical School. Our goals are to:• Identify specific unmet needs in cardiovascular biomarker and pathway discovery (e.g., genomic markers of subclinical premature coronary artery disease, serum biomarkers of myocardial ischemia)• Match cutting-edge technologies with our unique patient cohorts for “first in man” studies• Establish the infrastructure necessary to phenotype patients with the targeted condition (from plasma samples, RNA, DNA, imaging, etc.) and enroll sufficiently sized cohort(s) with the requisite power to validate novel biomarkers.• Establish scientifically high priority research projects to target for independent funding.• Ultimately, develop novel therapeutic interventions.While efforts in translational investigation are already underway, this program will identify synergies between ongoing studies and catalyze new opportunities. Several of the ongoing projects that are anticipated to serve as cornerstones of this effort include:Proteomics and Metabolomics Studies (PI: Gerszten , Wang)
Recent advances in proteomic and metabolic profiling technologies have enhanced the feasibility of high throughput patient screening for the diagnosis of disease states. Small biochemicals and proteins are the end result of the entire chain of regulatory changes that occur in response to physiological stressors, disease processes, or drug therapy. In addition to serving as biomarkers, both circulating metabolites and proteins participate as regulatory signals, such as in the control of blood pressure. Our ongoing studies have helped pioneer the application of novel mass spectrometry and liquid chromatography techniques to plasma analysis. In parallel with the profiling efforts, we have developed statistical software for functional pathway trend analysis and used it to demonstrate significant coordinate changes in specific pathways. Such analysis allows us to gain insight into the functionally relevant cellular mechanisms contributing to disease pathways and increases the likelihood that prospective biomarkers will be validated in other patient cohorts. Support for this effort would be synergistic with ongoing funding, including the recent appointment and support for Dr. Gerszten to lead a metabolomics initiative at the Broad Institute.Cardiovascular Genetics and Genomics Studies (PIs: Kathiresan, Newton-Cheh,Wang, and O’Donnell)
Through the Human Genome Project and the International Haplotype Map project, researchers now have available the complete human genome sequence, a nearly complete set of common single nucleotide polymorphisms (SNPs), and a map of the patterns of correlation (“linkage disequilibrium”) among SNPs. Research on a large-scale is now possible to define associations of common, complex human cardiovascular diseases —such as myocardial infarction and sudden cardiac death—with genetic variants using candidate gene and genome-wide association studies, gene sequencing, and family-based linkage studies. Specific diseases and traits being studied by CVRC researchers include early-onset myocardial infarction, sudden cardiac death, blood lipids, blood pressure, electrocardiographic QT interval and blood hemostatic factor levels. These studies draw clinical material from the Massachusetts General Hospital and from collaborations with population-based epidemiologic cohorts such as the Framingham Heart Study. Like the metabolomics/proteomics work, these efforts build on the technologic and scientific expertise at the Broad Institute. Specifically, CVRC researchers leverage the Broad Institute’s expertise in large-scale genotyping, genomics, and statistical genetics. The collaboration between the Massachusetts General Hospital, the Framingham Heart Study, and the Broad Institute brings together resources that are unique to each institution to identify genes related to complex cardiovascular traits and to ultimately impact human health.Chemical Biology Program (PIs: Peterson and Shaw) Dr. Peterson’s group has championed the zebrafish as a tool for drug discovery. The zebrafish has become a widely used model organism because of its fecundity, its morphological and physiological similarity to mammals, the existence of many genomic tools and the ease with which large, phenotype-based screens can be performed. Because of these attributes, the zebrafish also provides opportunities to accelerate the process of drug discovery. By combining the scale and throughput of in vitro screens with the physiological complexity of animal studies, the zebrafish promises to contribute to several aspects of the drug development process, including target identification, disease modeling, lead discovery and toxicology. The Program in Translational Medicine will specifically support efforts to test novel pro-angiogenic factors (discovered as suppressors of the “gridlock” phenotype in zebrafish) on human cells such as circulating endothelial precursors.Dr. Shaw’s group is studying the cellular effects of human disease mutations in patient samples, by perturbing cells with a panel of thousands of drugs, and asking whether mutant versus wild-type cells react differently to a given biochemical (reminiscent of a genetic interaction screen). Dr. Shaw has demonstrated the feasibility of this approach using lymphoblast cell lines from a family affected by a monogenic form of diabetes (MODY1), and shown that glucocorticoid signaling differs between affected vs. unaffected patients. Because his studies incorporate the use of FDA-approved drugs, he can quickly identify both potentially “druggable” disease pathways as well as novel therapeutic agents. Further validation of these efforts in other monogenic disorders, such as LDL-receptor deficient patients is planned next. Ultimately this work will be extended to studies in complex genetic diseases.Director: Rob Gerszten, MDPrincipal Investigators:
• Farouc Jaffer, MD, PhD
• Sekar Kathiresan, MD
• Chris Newton-Cheh, MD, MPH
• Randall Peterson, PhD
• Stanley Shaw, MD, PhD
• Thomas Wang, MD

Genetic Basis of Cardiomyopathy

Original gene identification for Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy, Autosomal Dominant

McNally E, MacLeod H, Dellefave L. Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy, Autosomal Dominant. 2005 Apr 18 [Updated 2009 Oct 13]. In: Pagon RA, Bird TD, Dolan CR, et al., editors. GeneReviews™ [Internet]. Seattle (WA): University of Washington, Seattle; 1993-.

Summary

Disease characteristics. Autosomal dominant arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by progressive fibrofatty replacement of the myocardium that predisposes to ventricular tachycardia and sudden death in young individuals and athletes. It primarily affects the right ventricle; with time, it may also involve the left ventricle. The presentation of disease is highly variable even within families, and affected individuals may not meet established clinical criteria. The mean age at diagnosis is 31 years (±13; range: 4-64 years).

Available from:

http://www.ncbi.nlm.nih.gov/books/NBK1131/

Pan Cardiomyopathy Panel

@the Center for Personalized Genetic Medicine of Partners HealthCare and Harvard Medical School

The Pan Cardiomyopathy (PCM) Panel contains 51 cardiomyopathy genes including Titin (TTN), which encodes the largest human protein. This panel covers genes associated with HCM, DCM, RCM, LVNC, ARVC and CPVT and uses a combination of Next Generation Sequencing technology and conventional Sanger sequencing.

For illustrative reference, click to see one of our images or diagrams. Genes on Pan Cardiomyopathy Panels, Disease-Gene Associations, Gene Cellular Location.

Please select on the disease to read more: HCM,DCM, ARVC/CPVT, or LVNC.

Current Tests:

Pan Cardiomyopathy Panel – 51 genes

  • HCM Panel – 18 genes§
  • DCM Panel – 27 genes§
  • ARVC/CPVT Panel – 8 genes§
  • LVNC Panel – 10 genes§

§Optional reflex to remaining genes

Storage Cardiomyopathy – please select a disease to learn more

For any other single gene tests, please call the LMM at 617-768-8499 or lmm@partners.org.

For Variant Classification Rules – Lab for Molecular Medicine (LMM)

http://pcpgm.partners.org/sites/default/files/LMM/Resources/LMM_VariantClassification_05.26.11.pdf 

For LMM Reference Sequences

http://pcpgm.partners.org/sites/default/files/LMM/Resources/LMMRefSeq-2.20.13.pdf

When to order which panel?

The Pan Cardiomyopathy panel may shorten the “testing odyssey” when a clear diagnosis has not been established. However, because many genes have not yet been associated with more than one cardiomyopathy, interpretation of novel variants may be more difficult when they are found in a gene that is not (yet) known to cause the patient’s cardiomyopathy. Please note: We are expecting an increase in “variants of unknown significance” and recommend careful consideration of the following factors when deciding whether to order the full panel or the disease specific sub-panels. The Pan Cardiomyopathy Panel may be best suited for patients who have already exhausted current testing options or whose clinical diagnosis is not yet clear. It may also be a good first line test for patients who have a family history where the number of living affected relatives would allow segregation analysis to establish or rule out pathogenicity for “variants of unknown significance (VUSs)”. Finally, the patient’s personal preferences should be considered as VUSs can cause anxiety.

Disease Backgrounds

Hypertrophic cardiomyopathy (HCM) is characterized by unexplained left ventricular hypertrophy (LVH) in a non-dilated ventricle. With a prevalence estimated to be ~1/500 in the general population, HCM is the most common monogenic cardiac disorder. To date, over 1000 variants have been identified in genes causative of HCM, most of which affect the sarcomere, the contractile unit of the cardiac muscle. In addition, defects in genes involved in storage diseases, such as LAMP2, PRKAG2 and GLA, typically cause systemic disease but may also result in predominant cardiac manifestations, which can mimic hypertrophic cardiomyopathy (HCM). For additional information about HCM, please visit GeneReviews. 

Dilated cardiomyopathy (DCM) is characterized by ventricular chamber enlargement and systolic dysfunction with normal left ventricular wall thickness. The estimated prevalence of DCM is 1/2,500 and about 20-35% of cases have a family history showing a predominantly autosomal mode of inheritance. To date, over 40 genes have been demonstrated to cause DCM, encoding proteins involved in the sarcomere, Z-disk, nuclear lamina, intermediate filaments and the dystrophin-associated glycoprotein complex. Variants in some genes cause additional abnormalities: LMNA variants are frequently found in DCM that occurs with progressive conduction system disease. Variants in the TAZ gene cause Barth syndrome, an X-linked cardioskeletal myopathy in infants. In addition, variants in several genes (including LMNA, DES, SGCD, TCAP and EMD) can cause DCM in conjunction with skeletal myopathy.  For additional information about DCM, please visit GeneReviews.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is estimated to affect approximately 1/5,000 individuals in the general population, about half of which have a family history. The disease is characterized by replacement of myocytes by fatty or fibrofatty tissue, mainly in the right ventricle. The resulting manifestations are broad and include ventricular tachyarrhythmias and sudden death in young individuals and athletes. ARVC is typically inherited in an autosomal dominant fashion with incomplete penetrance and variable expressivity and to date, 5 ARVC genes (DSP, DSC2, DSG2, PKP2, TMEM43) have been identified, all but one (TMEM43) encode components of the desmosome. For more information about ARVC, please visit GeneReviews.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is typically characterized by exercise induced syncope due to ventricular tachycardia in individuals without structural heart disease. Two CPVT genes are known to date (RYR2 – autosomal dominant; CASQ2 – autosomal recessive). For more information about CPVT, please visit GeneReviews.

Left ventricular noncompaction (LVNC) has recently been established as a specific type of cardiomyopathy and is characterized by a spongy appearance of the left ventricular myocardium, resulting from an arrest in normal cardiac development. LVNC can be found in isolation or in association with other cardiomyopathies (HCM, DCM) as well as congenital cardiac abnormalities. The population prevalence is not known but LVNC is reported in ~0.014% of echocardiograms. LVNC is often familial and the genetic spectrum is beginning to emerge although it is not yet well defined. LVNC genes reported to date include ACTC, DTNA, LDB3, MYBPC3, MYH7, TAZ, and TNNT2 (Montserrat 2007, Klaassen 2008; Kaneda 2007, Zaragoza 2007; reviewed in: Maron 2006, Finsterer 2009). For more information about LVNC, please visit OMIM.org.

For any additional information, please contact us at 617-768-8500 or lmm@partners.org.

SOURCE:
Genes: 51 genesMethodology: A combination of next generation sequencing technology and Sanger sequencingAnalytical Sensitivity:Substitutions: 100% (95%CI=98.5-100)Small InDels: 95% (95%CI=83-99)Clinical Sensitivity: See below.Additional Links:

Cardiomyopathy

Price TAT CPT Codes
Pan Cardiomyopathy Panel (51 Genes)  –  lmPCM-pnlAv2_L 
$3,950 8-12 wks 81479
HCM Panel (18 Genes)  –  lmPCM-pnlB_L
$3,200 8-12 wks 81479
DCM Panel (27 Genes)  –  lmPCM-pnlCv2_L
$3,850 8-12 wks 81479
ARVC/CPVT Panel (8 Genes)  –  lmPCM-pnlD_L
$3,000 8-12 wks 81479
LVNC Panel (10 Genes)  –  lmPCM-pnlE_L
$3,200 8-12 wks 81479
Remaining Pan Cardiomyopathy Genes (HCM Reflex)  –  lmPCM-pnlFv2_L
$2,000 8-12 wks 81479
Remaining Pan Cardiomyopathy Genes (DCM Reflex)  –  lmPCM-pnlGv2_L
$2,000 8-12 wks 81479
Remaining Pan Cardiomyopathy Genes (ARVC/CPVT Reflex)  –  lmPCM-pnlHv2_L
$2,000 8-12 wks 81479
Remaining Pan Cardiomyopathy Genes (LVNC Reflex)  –  lmPCM-pnlIv2_L
$2,000 8-12 wks 81479
Remaining Pan Cardiomyopathy Genes (Version 1 Reflex) – lmPCM-pnlL_L
$750 8-12 wks 81479
Unexplained Cardiac Hypertrophy Panel (2 genes)  –  lmUCH-pnlA_L
$1,500 3 wks 81479
ABCC9 Gene Sequencing  –  lmABCC9-a_L
$1,800 3 wks 81479
ACTC Gene Sequencing  –  lmACTC-a_L
$700 3 wks 81405
ACTN2 Gene Sequencing  –  lmACTN2-a_L
$1,500 3 wks 81479
CSRP3 Gene Sequencing  –  lmCSRP3-a_L
$900 3 wks 81479
CTF1 Gene Sequencing  –  lmCTF1-a_L
$800 3 wks 81479
DES Gene Sequencing  –  lmDES-a_L
$750 3 wks 81479
DSC2 Gene Sequencing  –  lmDSC2-a_L
$1,150 3 wks 81479
DSG2 Gene Sequencing  –  lmDSG2-a_L
$1,075 3 wks 81479
DSP Gene Sequencing  –  lmDSP-a_L
$1,700 3 wks 81479
DTNA Gene Sequencing – lmDTNA-a_L
$1,500 5-6 wks 81479
EMD Gene Sequencing  –  lmEMD-a_L
$450 3 wks 81479
GLA Gene Sequencing  –  lmGLA-a_L
$700 3 wks 81405
LAMP2 Gene Sequencing  –  lmLAMP2-a_L
$700 3 wks 81405
LDB3 Gene Sequencing  –  lmLDB3-a_L
$950 3 wks 81406
LMNA Gene Sequencing  –  lmLMNA-a_L
$700 3 wks 81406
MYBPC3 Gene Sequencing  –  lmMYBPC3-a_L
$1,500 3 wks 81407
MYH7 Gene Sequencing  –  lmMYH7-a_L
$1,700 3 wks 81407
MYL2 Gene Sequencing  –  lmMYL2-a_L
$700 3 wks 81405
MYL3 Gene Sequencing  –  lmMYL3-a_L
$700 3 wks 81405
PKP2 Gene Sequencing  –  lmPKP2-a_L
$1,500 3 wks 81479
PLN Gene Sequencing  –  lmPLN-a_L
$400 3 wks 81479
PRKAG2 Gene Sequencing  –  lmPRKAG2-a_L
$1,000 3 wks 81406
SCN5A Gene Sequencing – lmSCN5A-a_L
$1,700 5-6 wks 81407
SGCD Gene Sequencing  –  lmSGCD-a_L
$1,100 3 wks 81405
TAZ Gene Sequencing  –  lmTAZ-a_L
$700 3 wks 81406
TCAP Gene Sequencing  –  lmTCAP-a_L
$700 3 wks 81479
TMEM43 Gene Sequencing  –  lmTMEM43-a_L
$700 3 wks 81479
TNNI3 Gene Sequencing  –  lmTNNI3-a_L
$700 3 wks 81405
TNNT2 Gene Sequencing  –  lmTNNT2-a_L
$1,000 3 wks 81406
TPM1 Gene Sequencing  –  lmTPM1-a_L
$700 3 wks 81405
TTN Gene Sequencing  –  lmTTN-a_L
$3,000 8-12 wks 81479
TTR Gene Sequencing – lmTTR-a_L
$485 3 wks 81404
VCL Gene Sequencing  –  lmVCL-a_L
$1,500 3 wks 81479

Congenital Heart Disease/Defects

Price TAT CPT Codes
Congenital Heart Disease Panel A (GATA4, NKX2-5, JAG1)  –  lmCHD-pnlA_L
$1,300 4 wks 81479
ELN (Elastin) Gene Sequencing  –  lmELN-a_L
$1,300 4 wks  81479
GATA4 Gene Sequencing  –  lmGATA4-a_L
$750 3 wks 81479
JAG1 Gene Sequencing  –  lmJAG1-a_L
$1,100 3 wks 81407
NKX2-5 Gene Sequencing  –  lmNKX2-5-a_L
$600 3 wks 81479
SOURCE:

Lakdawala NK, Funke BH, Baxter S, Cirino A, Roberts AE, Judge DP, Johnson N, Mendelsohn NJ, Morel C, Care M, Chung WK, Jones C, Psychogios A, Duffy E, Rehm HL, White E, Seidman JG, Seidman CE, Ho CY.  Genetic Testing for Dilated Cardiomyopathy in Clinical Practice. J Card Fail 2012, In press.

Neri PM, Pollard SE, Volk LA, Newmark L, Varugheese M, Baxter S, Aronson SJ, Rehm HL, Bates DW. Usability of a Novel Clinician Interface for Genetic Results. J Biomed Informatics. 2012. In press.

Genomics @Brigham and Women’s Hospital and Harvard Medical School  

The goal of The Cardiovascular Genome Unit (TCGU) is to foster interdisciplinary interaction between clinical investigators and scientists to comprehensively explore the era of human genomic research. In particular, our aim would be to identify, categorize and characterize the genes and genetic pathways of the vascular and cardiac tissues of the cardiovascular system during oncogenesis, normal function and the pathogenesis of cardiovascular diseases.

    The Cardiovascular Genome Unit is responsible for indexing gene expression, profiling gene expression, identifying SNPs and generation of protein profiles from a wide variety of tissues representative of various anatomical regions as well as developmental and pathological stages in the cardiovascular system. This information resource emphasizes on cardiovascular disease and should aid in the discovery of disease causing genes, diagnostic and prognostic markers, drug targets, protein therapeutics and improved therapeutic strategies for cardiovascular disease.

    Our laboratory is the curator of a genome-based resource for molecular cardiovascular medicine consisting of over 52,000 ESTs generated from nine heart and artery libraries, representing different developmental stages and disease states (Liew et al 1994, Hwang et al 1997, Dempsey et al 2000). 

    This comprehensive catalogue of cardiac and hematopoietic genes is an unmined molecular resource for microarray analysis and a genetic gold mine for the discovery of genes that may play a role in cardiovascular disorders. In order to exploit this raw data, we propose to develop cDNA microarrays consisting of known and novel sequence-tagged genes. The arrayed clones provide an excellent substrate for expression profiling of cardiovascular disease, for example heart failure or ischemic heart disease, leading the potential discovery of diagnostic as well as prognostic markers.

    In order to accomplish the goals of the center, several cutting edge technologies are being employed.

The human cardiovascular research component of our labs.

One of the most efficient and effective strategies for the identification genes is the Expressed Sequence Tag (EST) approach.  In this approach, randomly selected cDNA clones are subjected to automated sequencing (PCR or plasmid templates) to generate a partial sequence from either the 5’- or 3’-end termed an EST.  This method allows for large-scale gene tagging and indexing from any tissue- or cell-type of interest.  A comprehensive cardiovascular gene index could be developed using a variety of cardiovascular tissues representing different anatomical, developmental and pathological states.

Comparing transcript profiles between different development or disease states is a powerful way to gain insight into the genetic changes underlying these events.  This is especially important when looking at complex systems, such as in development or disease (e.g. hypertension or atherosclerosis).  There are several unique approaches to this problem, several of which are:

a)      EST profile Comparison– After the production of a significant number of ESTs from 2 or more libraries, the frequencies of ESTs can be compared to identify those genes which are differentially expressed.     However, normalized or subtracted cDNA libraries cannot be used for this and this method is most effective for finding large differences in expression.

 

b)      cDNA Microarray Hybridization– The recent introduction of the cDNA microarray, a technology capable of analyzing the expression of thousands of genes simultaneously in a single experiment, may  provide one of the best ways to delineate gene expression patterns.  In the cDNA microarray, cDNA clones are spotted onto a glass slide matrix and hybridized with fluorescently labeled cDNA probes derived from total RNA pools of test and reference cells or tissues.  The signal intensity for each probe is quantified and any differences between the two samples becomes readily apparent.  Thus, the genetic changes underlying the phenotype of study can be identified at the level of a single gene. 

 

c)      Identification of Single Nucleotide Polymorphisms– SNPs are single-base heritable variations in the genome which occur once in approximately 1000 bases in the human genome and occur at a frequency of >1% in the human population.  SNPs provide an important genetic resource useful for disease gene discovery. including the identification of disease susceptible genes.  SNPs can be identified through comparison of EST sequences, DNA hybridization strategies and direct sequencing of genomic DNA.  The generation of a SNP database for genes expressed in the cardiovascular system will provide a valuable resource to aid in disease gene discovery. 

 

d)      Quantitative determination of expressed genes– the up- and down- regulated genes are crucial to the phenotypic expression of any given cell.  The frequency of gene expressed in development or disease state can be obtained from an EST approach using cDNA libraries as well as its intensity detected using microarrays.  Such results can be verified through RT-PCR analysis from the tissue samples.  A high through-put analysis of 96 samples can be performed by real-time PCR analyses.

Using our 10,000 element “CardioChip”, we elucidated over 100 differentially expressed genes in end-stage heart failure resulting from dilated cardiomyopathy. The results were published in

Am J Pathol. 2002 June; 160(6): 2035–2043.

Global Gene Expression Profiling of End-Stage Dilated Cardiomyopathy Using a Human Cardiovascular-Based cDNA Microarray

From Cardiovascular Genome Unit*, the Department of Medicine, and the Department of Anesthesiology,‡Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts; and the Department of Laboratory Medicine and Pathobiology,†University of Toronto, Toronto, Ontario, Canada

Abstract

To obtain a genomic portrait of heart failure derived from end-stage dilated cardiomyopathy (DCM), we explored expression analysis using the CardioChip, a nonredundant 10,848-element human cardiovascular-based expressed sequence tag glass slide cDNA microarray constructed in-house. RNA was extracted from the left ventricular free wall of seven patients undergoing transplantation, and five nonfailing heart samples. Cy3- and Cy5-labeled (and reverse dye-labeled) cDNA probes were synthesized from individual diseased or nonfailing adult heart RNA, and hybridized to the array. More than 100 transcripts were consistently differentially expressed in DCM >1.5-fold (versus pooled nonfailing heart,P < 0.05). Atrial natriuretic peptide was found to be up-regulated in DCM (19-fold compared to nonfailing, P < 0.05), as well as numerous sarcomeric and cytoskeletal proteins (eg, cardiac troponin, tropomyosin), stress response proteins (eg, HSP 40, HSP 70), and transcription/translation regulators (eg, CCAAT box binding factor, eIF-1AY). Down-regulation was most prominently observed with cell-signaling channels and mediators, particularly those involved in Ca2+ pathways (Ca2+/calmodulin-dependent kinase, inositol 1,4,5-trisphosphate receptor, SERCA). Most intriguing was the co-expression of several novel, cardiac-enriched expressed sequence tags. Quantitative real-time reverse transcriptase-polymerase chain reaction of a selection of these clones verified expression. Our study provides a preliminary molecular profile of DCM using the largest human heart-specific cDNA microarray to date.

Dilated cardiomyopathy (DCM) is characterized clinically by left ventricular dilatation, wall thinning, and homogeneous dysfunction of the myocardium leading to congestive heart failure. Genetically, DCM seems to evolve through primary mutations in the genes of the sarcomeric proteins. 1 However, recent evidence suggests that, despite distinct pathways leading to divergent endpoint phenotypes of each disease, there may exist some overlapping genetic modifiers leading to a conversion of one to the other. 2 How this occurs is under question; to understand this, a better knowledge of the molecular pathways and intermediary regulators is required.

Global analysis of gene expression has proven to be a fruitful means of examining the overall molecular portrait of a particular event as well as seeking out novel candidate transcripts that may play a role in formulating the phenotype or genotype of interest. By using this strategy, multiple genes and pathways in complex disorders can be visualized simultaneously, allowing for a feasible platform from which to investigate new and interesting genes. Using expressed sequence tag technology, our laboratory has generated a compendium of genes expressed in the human cardiovascular system, with the ultimate goal of assembling the intricacies of development and of disease, particularly the pathways leading to heart failure. 3 Through a computer-based in silico strategy, we have been able to identify—in a large scale—both known and previously unsuspected genetic modulators contributing to the growth of the myocardium from fetal through adult, and from normal to a perturbed hypertrophic phenotype. In contrast a gene-by-gene approach in elucidating the genes and mechanisms involved is time-consuming and cumbersome.

Recently, microarray technology has been used as a means of large-scale screening of vast numbers of genes—if not whole genomes—that possess differential expression in two distinct conditions. Although new and exciting developments have arisen in such fields as cancer 4 and yeast, 5 advances in understanding the complexity of cardiovascular disease, 6 specifically DCM, have been limited. One recent study examined gene expression in two failing hearts using oligo-based arrays. 7 Although the GeneChip® (Affymetrix, Santa Clara, CA) offers a carefully controlled systematic method of analysis, its current lack of user flexibility in its design hinders novel gene discovery currently available in tissue-specific arrays. Our laboratory has taken advantage of our vast previously acquired resources and has constructed what we believe to be the first ever custom-made cardiovascular-based cDNA microarray, which we term the “CardioChip.” 8 Its practicality and flexibility has allowed us to conceptualize the molecular events surrounding end-stage heart failure.

This report describes the most informative cDNA microarray-based analysis of end-stage heart failure derived from DCM currently available. Although we believe we have effectively demonstrated reproducibility and reliability of our technology (both for the entire array and for a selection of genes located on it), a larger n from our population would enhance the validity of our conclusions. Certainly, there exists no homogeneous heart failure genotype, especially among only seven DCM patients. Nonetheless, we have demonstrated a common expression pattern among our set of samples, from both microarray and QRT-PCR analysis. We are also limited by the genes (both in number and identity) present on this array. Although we are currently unable to spot every gene and gene cluster on our CardioChip, we have tried to draw from a diverse assortment of genes and gene pathways, both known and unknown. It must be emphasized that this investigation is not exhaustive; by no means does it attempt to fully characterize the molecular basis of heart failure. Its intention is to provide a preliminary portrait of global gene expression in complex cardiovascular disease using cDNA microarray and QRT-PCR technology, and to highlight the effectiveness of our ever-evolving platform for gene discovery. With even more patient samples and a CardioChip toward completeness, we will be in a better position to reap the important benefits from this initial work and expand our body of knowledge.

REFERENCES

http://www.pnas.org/content/91/22/10645.full.pdf

1. Towbin JA, Bowles NE: Genetic abnormalities responsible for dilated cardiomyopathy. Curr Cardiol Rep 2000, 2:475-480. [PubMed]
2. Chien KR: Stress pathways and heart failure. Cell 1999, 98:555-558. [PubMed]
3. Hwang JJ, Dzau VJ, Liew CC: Genomics and the pathophysiology of heart failure. Curr Cardiol Rep2001, 3:198-207. [PubMed]
4. Alizadeh AA, Eisen MB, Davis RE, Ma C, Lossos IS, Rosenwald A, Boldrick JC, Sabet H, Tran T, Yu X, Powell JI, Yang L, Marti GE, Moore T, Hudson J, Jr, Lu L, Lewis DB, Tibshirani R, Sherlock G, Chan WC, Greiner TC, Weisenburger DD, Armitage JO, Warnke R, Levy R, Wilson W, Grever M, Byrd JC, Botstein D, Brown PO, Staudt LM: Distinct types of diffuse large B-cell lymphoma identified by gene expression profiling. Nature 2000, 403:503-511. [PubMed]
5. Gasch AP, Spellman PT, Kao CM, Carmel-Harel O, Eisen MB, Storz G, Botstein D, Brown PO: Genomic expression programs in the response of yeast cells to environmental changes. Mol Biol Cell 2000, 11:4241-4257. [PMC free article] [PubMed]
6. Taylor LA, Carthy CM, Yang D, Saad K, Wong D, Schreiner G, Stanton LW, McManus BM: Host gene regulation during coxsackievirus B3 infection in mice: assessment by microarrays. Circ Res 2000, 87:328-334. [PubMed]
7. Yang J, Moravec CS, Sussman MA, DiPaola NR, Fu D, Hawthorn L, Mitchell CA, Young JB, Francis GS, McCarthy PM, Bond M: Decreased SLIM1 expression and increased gelsolin expression in failing human hearts measured by high-density oligonucleotide arrays. Circulation 2000, 102:3046-3052.[PubMed]
8. Barrans JD, Stamatiou D, Liew CC: Construction of a human cardiovascular cDNA microarray: portrait of the failing heart. Biochem Biophys Res Commun 2001, 280:964-969. [PubMed]
9. Hwang DM, Hwang WS, Liew CC: Single pass sequencing of a unidirectional human fetal heart cDNA library to discover novel genes of the cardiovascular system. J Mol Cell Cardiol 1994, 26:1329-1333.[PubMed]
10. Hwang DM, Dempsey AA, Lee CY, Liew CC: Identification of differentially expressed genes in cardiac hypertrophy by analysis of expressed sequence tags. Genomics 2000, 66:1-14. [PubMed]
11. Hwang DM, Dempsey AA, Wang RX, Rezvani M, Barrans JD, Dai KS, Wang HY, Ma H, Cukerman E, Liu YQ, Gu JR, Zhang JH, Tsui SK, Waye MM, Fung KP, Lee CY, Liew CC: A genome-based resource for molecular cardiovascular medicine: toward a compendium of cardiovascular genes. Circulation 1997,96:4146-4203. [PubMed]
12. Liew CC, Hwang DM, Fung YW, Laurenssen C, Cukerman E, Tsui S, Lee CY: A catalogue of genes in the cardiovascular system as identified by expressed sequence tags. Proc Natl Acad Sci USA 1994,91:10645-10649. [PMC free article] [PubMed]
13. Liew CC, Hwang DM, Wang RX, Ng SH, Dempsey A, Wen DH, Ma H, Cukerman E, Zhao XG, Liu YQ, Qiu XK, Zhou XM, Gu JR, Tsui S, Fung KP, Waye MM, Lee CY: Construction of a human heart cDNA library and identification of cardiovascular based genes (CVBest). Mol Cell Biochem 1997, 172:81-87.[PubMed]
14. Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ: Basic local alignment search tool. J Mol Biol1990, 215:403-410. [PubMed]
15. DeRisi J, Penland L, Brown PO, Bittner ML, Meltzer PS, Ray M, Chen Y, Su YA, Trent JM: Use of a cDNA microarray to analyze gene expression patterns in human cancer. Nat Genet 1996, 14:457-460.[PubMed]
16. Vikstrom KL, Bohlmeyer T, Factor SM, Leinwand LA: Hypertrophy, pathology, and molecular markers of cardiac pathogenesis. Circ Res 1998, 82:773-778. [PubMed]
17. Towbin JA: The role of cytoskeletal proteins in cardiomyopathies. Curr Opin Cell Biol 1998, 10:131-139.[PubMed]
18. Elliott K, Watkins H, Redwood CS: Altered regulatory properties of human cardiac troponin I mutants that cause hypertrophic cardiomyopathy. J Biol Chem 2000, 275:22069-22074. [PubMed]
19. Kimura A, Harada H, Park JE, Nishi H, Satoh M, Takahashi M, Hiroi S, Sasaoka T, Ohbuchi N, Nakamura T, Koyanagi T, Hwang TH, Choo JA, Chung KS, Hasegawa A, Nagai R, Okazaki O, Nakamura H, Matsuzaki M, Sakamoto T, Toshima H, Koga Y, Imaizumi T, Sasazuki T: Mutations in the cardiac troponin I gene associated with hypertrophic cardiomyopathy. Nat Genet 1997, 16:379-382. [PubMed]
20. Redwood C, Lohmann K, Bing W, Esposito GM, Elliott K, Abdulrazzak H, Knott A, Purcell I, Marston S, Watkins H: Investigation of a truncated cardiac troponin T that causes familial hypertrophic cardiomyopathy: Ca(2+) regulatory properties of reconstituted thin filaments depend on the ratio of mutant to wild-type protein. Circ Res 2000, 86:1146-1152. [PubMed]
21. Geisterfer-Lowrance AA, Kass S, Tanigawa G, Vosberg HP, McKenna W, Seidman CE, Seidman JG: A molecular basis for familial hypertrophic cardiomyopathy: a beta cardiac myosin heavy chain gene missense mutation. Cell 1990, 62:999-1006. [PubMed]
22. Thierfelder L, Watkins H, MacRae C, Lamas R, McKenna W, Vosberg HP, Seidman JG, Seidman CE: Alpha-tropomyosin and cardiac troponin T mutations cause familial hypertrophic cardiomyopathy: a disease of the sarcomere. Cell 1994, 77:701-712. [PubMed]
23. Arber S, Hunter JJ, Ross J, Jr, Hongo M, Sansig G, Borg J, Perriard JC, Chien KR, Caroni P: MLP-deficient mice exhibit a disruption of cardiac cytoarchitectural organization, dilated cardiomyopathy, and heart failure. Cell 1997, 88:393-403. [PubMed]
24. Dalakas MC, Park KY, Semino-Mora C, Lee HS, Sivakumar K, Goldfarb LG: Desmin myopathy, a skeletal myopathy with cardiomyopathy caused by mutations in the desmin gene. N Engl J Med 2000,342:770-780. [PubMed]
25. Satoh M, Takahashi M, Sakamoto T, Hiroe M, Marumo F, Kimura A: Structural analysis of the titin gene in hypertrophic cardiomyopathy: identification of a novel disease gene. Biochem Biophys Res Commun 1999, 262:411-417. [PubMed]
26. Olson TM, Michels VV, Thibodeau SN, Tai YS, Keating MT: Actin mutations in dilated cardiomyopathy, a heritable form of heart failure. Science 1998, 280:750-752. [PubMed]
27. Schonberger J, Seidman CE: Many roads lead to a broken heart: the genetics of dilated cardiomyopathy. Am J Hum Genet 2001, 69:249-260. [PMC free article] [PubMed]
28. Dempsey AA, Ton C, Liew CC: A cardiovascular EST repertoire: progress and promise for understanding cardiovascular disease. Mol Med Today 2000, 6:231-237. [PubMed]
29. Francis GS: Changing the remodeling process in heart failure: basic mechanisms and laboratory results. Curr Opin Cardiol 1998, 13:156-161. [PubMed]
30. Rao VU, Spinale FG: Controlling myocardial matrix remodeling: implications for heart failure.Cardiol Rev 1999, 7:136-143. [PubMed]
31. McKinsey TA, Olson EN: Cardiac hypertrophy: sorting out the circuitry. Curr Opin Genet Dev 1999,9:267-274. [PubMed]
32. Chien KR: Genomic circuits and the integrative biology of cardiac diseases. Nature 2000, 407:227-232. [PubMed]
33. Miyamoto MI, del Monte F, Schmidt U, DiSalvo TS, Kang ZB, Matsui T, Guerrero JL, Gwathmey JK, Rosenzweig A, Hajjar RJ: Adenoviral gene transfer of SERCA2a improves left ventricular function in aortic-banded rats in transition to heart failure. Proc Natl Acad Sci USA 2000, 97:793-798.[PMC free article] [PubMed]
34. Tada M, Yabuki M, Toyofuku T: Molecular regulation of phospholamban function and gene expression. Ann NY Acad Sci 1998, 853:116-129. [PubMed]
35. Marks AR: Cardiac intracellular calcium release channels: role in heart failure. Circ Res 2000, 87:8-11. [PubMed]
36. Dewaste V, Pouillon V, Moreau C, Shears S, Takazawa K, Erneux C: Cloning and expression of a cDNA encoding human inositol 1,4,5-trisphosphate 3-kinase C. Biochem J 2000, 352:343-351.[PMC free article] [PubMed]
Books (partial list):

Liew CC, Jackowski, G, Ma T, Jung, YC, Sole, MJ. Possible role of nonhistone chromatin proteins associated with heterogeneous nuclear RNA in myocardial differentiation and in the genesis of cardiomyopathy. In: Alpert NR, editor. Perspectives in
Cardiovascular Research. Raven Press; 1983. p. 497-511.

Liew CC, Takihara KY, Jandreski M, Liew J, Sole MJ. Structure and expression of human b-myosin heavy chain gene. In: Carraro U, editor. Sarcomeric and Non-sarcomeric Muscles: Basic and Applied Research Prospects for the 90s. Padova, Italy: Unipress
Padova; 1988. P 11-17.

Liew CC, Takihara KY, Liew J, Sole MJ. Characterization of human cardiac myosin heavy chain genes. In: Wu F, Wu CW, editors. Structure and Function of Nucleic Acids and Proteins, New York, Raven Press; 1990. pp.303-309.

Wang RX, Cukerman E, Chen B, Liew CC. Differential screening and megasequencing of human heart cDNA library: A search for genes associated with heart failure. In: Dhalla NS, Pierce GN, Panagia V, Beamish RE, editors. Boston: Kluwer Academic Press; 1995. P. 67-77.

Dempsey A, Liew CC. Genes involved in normal cardiac development. In: Sheridan DJ, editor. Left Ventricular Hypertrophy. London: Churchill Communications Europe Ltd; 1998: p. 61-70.

Tan K, Dempsey A, Liew CC. Cardiac genes and gene databases for cardiovascular disease genetics. In: Hollenberg NK, editor. Current Hypertension Reports. Philadelphia: Current Science Group; 1999: Vol 1:51-58.

Liew, CC. Expressed Sequence Tags. In: Encyclopedia of Molecular Medicine, Ed: T. Creighton, John Wiley and Son, New York. 2001

Hwang J-J, Dzau V and Liew CC. Genomics and thePathophysiology of Heart Failure. In: Current Cardiology Reports; Current Science Inc; 2001: Vol 3: 198-207.

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Secondary Hypertension caused by Aldosterone-producing Adenomas caused by Somatic Mutations in ATP1A1 and ATP2B3

Posted in Biological Networks, Gene Regulation and Evolution, Biomarkers & Medical Diagnostics, CANCER BIOLOGY & Innovations in Cancer Therapy, Cardiovascular Pharmacogenomics, Cell Biology, Signaling & Cell Circuits, Chemical Genetics, Computational Biology/Systems and Bioinformatics, Frontiers in Cardiology and Cardiovascular Disorders, Genome Biology, Genomic Testing: Methodology for Diagnosis, HTN, Molecular Genetics & Pharmaceutical, Personalized and Precision Medicine & Genomic Research, tagged , , , , , on February 21, 2013| Leave a Comment »

Reporter: Aviva Lev-Ari, PhD, RN

Somatic mutations in ATP1A1 and ATP2B3 lead to aldosterone-producing adenomas and secondary hypertension

Nature Genetics

Published online 17 February 2013
Mutations affecting a pair of related enzyme-coding genes can contribute to the 

risk of benign glandular tumors 

called adenomas and secondary hypertension, a new 

Nature Genetics

 study suggests. An international team led by investigators in Germany performed

exome sequencing

on matched tumor and normal samples from nine individuals with forms of adenoma that enhance aldosterone hormone production. This leads to a type of so-called aldosteronism that can bump up blood pressure and cause other adverse symptoms.

When researchers sorted through the exome sequence data, they saw ties between aldosterone-producing adenoma and mutations in two ATPase genes — ATP1A1 and ATP2B3 — that participate in sodium/potassium and calcium signaling, respectively. Somatic ATP1A1 mutations turned up in more than 5 percent of 308 aldosterone-producing adenoma samples screened subsequently, the team noted, while 1.6 percent of those tumors contained ATP2B3 alterations.

“[T]hese findings expand the spectrum of somatic alterations leading to [aldosterone-producing adenomas] to two members of the P-type ATPase pump family, extend knowledge of the molecular mechanism leading to [aldosterone-producing adenoma],” the Ludwig Maximilian University of Munich researcher Martin Reincke, the study’s corresponding author, and colleagues wrote, “and indicate new potential therapeutic targets for the most frequent secondary form of arterial hypertension.”

SOURCE:

http://www.genomeweb.com//node/1194476?hq_e=el&hq_m=1505701&hq_l=6&hq_v=6fcaf1aef4

Somatic mutations in ATP1A1 and ATP2B3 lead to aldosterone-producing adenomas and secondary hypertension

Primary aldosteronism is the most prevalent form of secondary hypertension. To explore molecular mechanisms of autonomous aldosterone secretion, we performed exome sequencing of aldosterone-producing adenomas (APAs). We identified somatic hotspot mutations in the ATP1A1 (encoding an Na+/K+ ATPase α subunit) and ATP2B3 (encoding a Ca2+ ATPase) genes in three and two of the nine APAs, respectively. These ATPases are expressed in adrenal cells and control sodium, potassium and calcium ion homeostasis. Functional in vitro studies of ATP1A1 mutants showed loss of pump activity and strongly reduced affinity for potassium. Electrophysiological ex vivo studies on primary adrenal adenoma cells provided further evidence for inappropriate depolarization of cells with ATPase alterations. In a collection of 308 APAs, we found 16 (5.2%) somatic mutations in ATP1A1 and 5 (1.6%) in ATP2B3.

Mutation-positive cases showed

  • male dominance,
  • increased plasma aldosterone concentrations and
  • lower potassium concentrations compared with mutation-negative cases.

In summary, dominant somatic alterations in two members of the ATPase gene family result in autonomous aldosterone secretion.

Author information

Primary authors

  1. These authors contributed equally to this work.

    • Maria-Christina Zennaro &
    • Tim M Strom

Affiliations

  1. Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität München, Munich, Germany.

    • Felix Beuschlein,
    • Andrea Osswald,
    • Urs D Lichtenauer,
    • Evelyn Fischer &
    • Martin Reincke

  2. Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche Scientifique (UMRS) 970, Paris Cardiovascular Research Center, Paris, France.

    • Sheerazed Boulkroun,
    • Laurence Amar,
    • Benoit Samson-Couterie,
    • Pierre-Francois Plouin,
    • Xavier Jeunemaitre &
    • Maria-Christina Zennaro

  3. Université Paris Descartes, Sorbonne Paris Cité, Paris, France.

    • Sheerazed Boulkroun,
    • Laurence Amar,
    • Benoit Samson-Couterie,
    • Pierre-Francois Plouin,
    • Xavier Jeunemaitre &
    • Maria-Christina Zennaro

  4. Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.

    • Thomas Wieland,
    • Anett Walther,
    • Thomas Schwarzmayr,
    • Susanne Diener,
    • Elisabeth Graf,
    • Thomas Meitinger &
    • Tim M Strom

  5. Department of Biomedicine, Aarhus University, Aarhus, Denmark.

    • Hang N Nielsen,
    • Vivien R Schack &
    • Bente Vilsen

  6. Medizinische Zellbiologie, Universität Regensburg, Regensburg, Germany.

    • David Penton,
    • Philipp Tauber &
    • Richard Warth

  7. Assistance Publique–Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France.

    • Laurence Amar,
    • Pierre-Francois Plouin,
    • Xavier Jeunemaitre &
    • Maria-Christina Zennaro

  8. Department of Medicine I, Endocrine and Diabetes Unit, University Hospital Würzburg, Würzburg, Germany.

    • Bruno Allolio

  9. Centre National de la Recherche Scientifique (CNRS), Institut des Hautes Etudes Scientifiques, Bures sur Yvette, France.

    • Arndt Benecke

  10. Clinical Endocrinology, Campus Mitte, University Hospital Charité, Berlin, Germany.

    • Marcus Quinkler

  11. Department of Medicine, University of Padova, Padova, Italy.

    • Francesco Fallo

  12. Endocrine Unit, Department of Medicine, University of Padova, Padova, Italy.

    • Franco Mantero

  13. Institute of Human Genetics, Technische Universität München, Munich, Germany.

    • Thomas Meitinger &
    • Tim M Strom

  14. DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany.

    • Thomas Meitinger

  15. Department of Medical Sciences, Division of Internal Medicine and Hypertension, University of Torino, Turin, Italy.

    • Paolo Mulatero

Contributions

S.B., H.N.N., U.D.L., D.P., V.R.S., A.W., P.T., S.D. and B.S.-C. performed the experiments. A.O., T.W., L.A., E.F., T.S., T.M.S., E.G. and A.B. performed statistical analysis and analyzed the data. B.A., M.Q., F.F., P.-F.P., F.M. and P.M. contributed materials. F.B., T.M., X.J., R.W., B.V., M.-C.Z., T.M.S. and M.R. jointly supervised research, conceived and designed the experiments, analyzed the data, contributed reagents, materials and/or analysis tools and wrote the manuscript.

SOURCE:

http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.2550.html

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