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Posts Tagged ‘Low-density lipoprotein’


HOT TOPICS 2014: Heart – The medpage TODAY View

Reporter: Aviva Lev-Ari, PhD, RN

HOT TOPICS 2014: Heart – Medical 1
(Post Date: 1/2/14)

VIEW VIDEO

http://www.medpagetoday.com/HOTTOPICS2014/special-reports/SpecialReports-Videos/365

HOT TOPICS 2014: Heart – Medical 1
(Post Date: 1/2/14)
Discussants: 
Steven Nissen, MD – Cleveland Clinic
Clyde Yancy, MD – Northwestern University, Feinberg School of Medicine
Robert Califf, MD – Duke Medical Center
Elliott Antman, MD – BWH

 

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LDL, HDL, TG, ApoA1 and ApoB: Genetic Loci Associated With Plasma Concentration of these Biomarkers – A Genome-Wide Analysis With Replication

Reporter: Aviva Lev-Ari, PhD, RN

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 LPLgene, 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 GCKRgene 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 SORT1gene, 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

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Genetics of Aortic and Carotid Calcification: The Role of Serum Lipids

Reporter: Aviva Lev-Ari, PhD, RN

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-mailm.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

 

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Two Mutations, in the PCSK9 Gene: Eliminates a Protein involved in Controlling LDL Cholesterol

Reporter: Aviva Lev-Ari, PhD, RN

UPDATED on 11/15/2013

Relax, PCSK9ers: FDA won’t roadblock blockbusters from Sanofi, Amgen

By Damian Garde

On the heels of new guidelines casting doubts on a much-hyped new class of cholesterol drugs, the FDA said it would not demand long and costly outcomes trials before approving PCSK9 treatments from the likes of Amgen ($AMGN), Sanofi ($SNY) and Regeneron ($REGN), clearing the way for treatments expected to rake in up to $3 billion a year.

As Bloomberg reports, the FDA plans to stick to its guns in vetting cardiovascular drugs, looking at reductions in LDL cholesterol and blood pressure as surrogate endpoints for long-term health benefits. That’s a relief for the developers of PCSK9-targeting drugs, who have faced mounting uncertainty about what they’ll need to do to get their would-be blockbusters to market. Partners Sanofi and Regeneron lead the pack with the promising alirocumab, followed by Amgen, Pfizer ($PFE) and numerous others.

Earlier this week, the American College of Cardiology and the American Heart Association put out new guidelines for prescribing cholesterol treatments, recommending tried-and-true statins over more novel therapies because the old drugs’ down-the-line cardiovascular benefits are well-told. That stirred up long-running concerns that the FDA would toughen up its requirements for the coming crop of PCSK9 treatments, asking drug developers to dump millions into long-term studies that demonstrate hard outcomes

But while PCSK9 developers may not have to worry about new regulatory hurdles, what’s good enough for the FDA won’t necessarily sway payers, and the billion-dollar sales estimates tied to PCSK9 drugs are contingent on widespread adoption. With that in mind, Pfizer is plotting a massive, 22,000-patient outcomes trial, looking to demonstrate the PCSK9-targeting RN-316’s ability to improve cardiovascular health in the long run, a move that may spur its competitors to follow suit.

And the FDA’s conventional wisdom on cardiovascular endpoints may not stand pat. Eric Colman, a deputy director at CDER, told Bloomberg the agency is keeping a close eye on a post-market study of Merck’s ($MRK) Vytorin, and if the drug’s LDL-lowering ability doesn’t translate to lower rates of cardiovascular events, it may well rethink its requirements.

Related Articles:

AstraZeneca wins, Merck and AbbVie lose with new statin-use guidelines

Sanofi, Regeneron take the lead in blockbuster PhIII race of PCSK9 drugs

Pfizer bets big on PCSK9 with ‘massive’ Phase III outcomes study

 SOURCE

From: FierceBiotech <editors@fiercebiotech.com>
Reply-To: <editors@fiercebiotech.com>
Date: Fri, 15 Nov 2013 17:56:42 +0000 (GMT)
To: <avivalev-ari@alum.berkeley.edu>
Subject: | 11.15.13 | Sanofi, Amgen dodge PCSK9 hurdles

 

http://www.nature.com/news/genetics-a-gene-of-rare-effect-1.12773?goback=%2Egde_96118_member_230797138

Genetics: A Gene of Rare Effect

A mutation that gives people rock-bottom cholesterol levels has led geneticists to what could be the next blockbuster heart drug.

Stephen S. Hall

09 April 2013
ADAPTED FROM: PETER DAZELEY/GETTY

Indeed, Tracy’s well-being has been inspiring to doctors, geneticists and now pharmaceutical companies precisely because she is so normal. Using every tool in the modern diagnostic arsenal — from brain scans and kidney sonograms to 24-hour blood-pressure monitors and cognitive tests — researchers at the Texas medical centre have diagnostically sliced and diced Tracy to make sure that the two highly unusual genetic mutations she has carried for her entire life have produced nothing more startling than an incredibly low level of cholesterol in her blood. At a time when the target for low-density lipoprotein (LDL) cholesterol, more commonly called ‘bad cholesterol’, in Americans’ blood is less than 100 milligrams per decilitre (a level many people fail to achieve), Tracy’s level is just 14.

A compact woman with wide-eyed energy, Tracy (not her real name) is one of a handful of African Americans whose genetics have enabled scientists to uncover one of the most promising compounds for controlling cholesterol since the first statin drug was approved by the US Food and Drug Administration in 1987. Seven years ago, researchers Helen Hobbs and Jonathan Cohen at UT-Southwestern reported1 that Tracy had inherited two mutations, one from her father and the other from her mother, in a gene called PCSK9, effectively eliminating a protein in the blood that has a fundamental role in controlling the levels of LDL cholesterol. African Americans with similar mutations have a nearly 90% reduced risk of heart disease. “She’s our girl, our main girl,” says Barbara Gilbert, a nurse who has drawn some 8,000 blood samples as part of Cohen and Hobbs’ project to find genes important to cholesterol metabolism.

Of all the intriguing DNA sequences spat out by the Human Genome Project and its ancillary studies, perhaps none is a more promising candidate to have a rapid, large-scale impact on human health than PCSK9. Elias Zerhouni, former director of the US National Institutes of Health (NIH) in Bethesda, Maryland, calls PCSK9 an “iconic example” of translational medicine in the genomics era. Preliminary clinical trials have already shown that drugs that inhibit the PCSK9 protein — used with or without statins — produce dramatic reductions in LDL cholesterol (more than 70% in some patients). Half-a-dozen pharmaceutical companies — all aiming for a share of the global market for cholesterol-reducing drugs that could reach US$25 billion in the next five years according to some estimates — are racing to the market with drugs that mimic the effect of Tracy’s paired mutations.

Free interview

Stephen Hall talks about Sharlayne’s unusual condition and whether similar cases might lead to a new line of drugs.

Zerhouni, now an in-house champion of this class of drug as an executive at drug firm Sanofi, headquartered in Paris, calls the discovery and development of PCSK9 a “beautiful story” in which researchers combined detailed physical information about patients with shrewd genetics to identify a medically important gene that has made “super-fast” progress to the clinic. “Once you have it, boy, everything just lines up,” he says. And although the end of the PCSK9 story has yet to be written — the advanced clinical trials now under way could still be derailed by unexpected side effects — it holds a valuable lesson for genomic research. The key discovery about PCSK9‘s medical potential was made by researchers working not only apart from the prevailing scientific strategy of genome research over the past decade, but with an almost entirely different approach.

As for Tracy, who lives in the southern part of Dallas County, the implications of her special genetic status have become clear. “I really didn’t understand at first,” she admits. “But now I’m watching ads on TV [for cholesterol-lowering drugs], and it’s like, ‘Wow, I don’t have that problem’.”

A heart problem

Cardiovascular disease is — and will be for the foreseeable future, according to the World Health Organization — the leading cause of death in the world, and its development is intimately linked to elevated levels of cholesterol in the blood. Since their introduction, statin drugs have been widely used to lower cholesterol levels. But Jan Breslow, a physician and geneticist at Rockefeller University in New York, points out that up to 20% of patients cannot tolerate statins’ side effects, which include muscle pain and even forgetfulness. And in many others, the drugs simply don’t control cholesterol levels well enough.

The search for better treatments for heart disease gained fresh impetus after scientists published the draft sequence of the human genome in 2001. In an effort to identify the genetic basis of common ailments such as heart disease and diabetes, geneticists settled on a strategy based on the ‘common variant hypothesis’. The idea was that a handful of disease-related versions (or variants) of genes for each disease would be common enough — at a frequency of roughly 5% or so — to be detected by powerful analyses of the whole genome. Massive surveys known as genome-wide association studies compared the genomes of thousands of people with heart disease, for example, with those of healthy controls. By 2009, however, many scientists were lamenting the fact that although the strategy had identified many common variants, each made only a small contribution to the disease. The results for cardiovascular disease have been “pretty disappointing”, says Daniel Steinberg, a lipoprotein expert at the University of California, San Diego.

Single-minded: Helen Hobbs and Jonathan Cohen’s approach to heart-disease genetics yielded a target for drugs that could compete with statins.MISTY KEASLER/REDUX/EYEVINE

More than a decade earlier, in Texas, Hobbs and Cohen had taken the opposite tack. They had backgrounds in Mendelian, or single-gene, disorders, in which an extremely rare variant can have a big — often fatal — effect. They also knew that people with a particular Mendelian disorder didn’t share a single common mutation in the affected gene, but rather had a lot of different, rare mutations. They hypothesized that in complex disorders, many different rare variants were also likely to have a big effect, whereas common variants would have relatively minor effects (otherwise natural selection would have weeded them out). “Jonathan and I did not see any reason why it couldn’t be that rare variants cumulatively contribute to disease,” Hobbs says. To find these rare variants, the pair needed to compile detailed physiological profiles, or phenotypes, of a large general population. Cohen spoke of the need to “Mendelize” people — to compartmentalize them by physiological traits, such as extremely high or low cholesterol levels, and then look in the extreme groups for variations in candidate genes known to be related to the trait.

The pair make a scientific odd couple. Hobbs, who trained as an MD, is gregarious, voluble and driven. Cohen, a soft-spoken geneticist from South Africa, has a laid-back, droll manner and a knack for quantitative thinking. In 1999, they set out to design a population-based study that focused on physical measurements related to heart disease. Organized with Ronald Victor, an expert on high blood pressure also at UT Southwestern, and funded by the Donald W. Reynolds Foundation in Las Vegas, Nevada, the Dallas Heart Study assembled exquisitely detailed physiological profiles on a population of roughly 3,500 Dallas residents2. Crucially, around half of the participants in the study were African Americans, because the researchers wanted to probe racial differences in heart disease and high blood pressure. The team measured blood pressure, body mass index, heart physiology and body-fat distribution, along with a battery of blood factors related to cholesterol metabolism — triglycerides, high-density lipoprotein (HDL) cholesterol and LDL cholesterol. In the samples of blood, of course, they also had DNA from each and every participant.

As soon as the database was completed in 2002, Hobbs and Cohen tested their rare-variant theory by looking at levels of HDL cholesterol. They identified the people with the highest (95th percentile) and lowest (5th percentile) levels, and then sequenced the DNA of three genes known to be key to metabolism of HDL cholesterol. What they found, both in Dallas and in an independent population of Canadians, was that the number of mutations was five times higher in the low HDL group than in the high group3. This made sense, Cohen says, because most human mutations interfere with the function of genes, which would lead to the low HDL numbers. Published in 2004, the results confirmed that rare, medically important mutations could be found in a population subdivided into extreme phenotypes.

Armed with their extensive database of cardiovascular traits, Hobbs and Cohen could now dive back into the Dallas Heart Study whenever they had a new hypothesis about heart disease and, as Cohen put it, “interrogate the DNA”. It wasn’t long before they had an especially intriguing piece of DNA at which to look.

The missing link

In February 2003, Nabil Seidah, a biochemist at the Clinical Research Institute of Montreal in Canada, and his colleagues reported the discovery of an enigmatic protein4. Seidah had been working on a class of enzymes known collectively as proprotein convertases, and the researchers had identified what looked like a new member of the family, called NARC-1: neural apoptosis-regulated convertase 1.

“We didn’t know what it was doing, of course,” Seidah says. But the group established that the gene coding the enzyme showed activity in the liver, kidney and intestines as well as in the developing brain. The team also knew that in humans the gene mapped to a precise genetic neighbourhood on the short arm of chromosome 1.

That last bit of geographical information pointed Seidah to a group led by Catherine Boileau at the Necker Hospital in Paris. Her team had been following families with a genetic form of extremely high levels of LDL cholesterol known as familial hypercholesterolaemia, which leads to severe coronary artery disease and, often, premature death. Group member Marianne Abifadel had spent five fruitless years searching a region on the short arm of chromosome 1 for a gene linked to the condition. When Seidah contacted Boileau and told her that he thought NARC-1 might be the gene she was looking for, she told him, “You’re crazy”, Seidah recalls. Seidah bet her a bottle of champagne that he was correct; within two weeks, Boileau called back, saying: “I owe you three bottles.”

“The PCSK9 story is a terrific example of an up-and-coming pattern of translational research.”

In 2003, the Paris and Montreal groups reported that the French families with hypercholesterolaemia had one of two mutations in this newly discovered gene, and speculated that this might cause increased production of the enzyme5. Despite Seidah’s protests, the journal editors gave both the gene and its protein product a new name that fit with standard nomenclature: proprotein convertase subtilisin/kexin type 9, or PCSK9. At around the same time, Kara Maxwell in Breslow’s group at Rockefeller University6 and Jay Horton, a gastroenterologist at UT-Southwestern7 also independently identified the PCSK9 gene in mice and revealed its role in a previously unknown pathway regulating cholesterol8.

The dramatic phenotype of the French families told Hobbs that “this is an important gene”. She also realized that in genetics, mutations that knock out a function are much more common than ones that amplify function, as seemed to be the case with the French families. “So immediately I’m thinking, a loss-of-function mutation should manifest as a low LDL level,” she says. “Let’s go and see if that’s true.”

Going to extremes

Hobbs and Cohen had no further to look than in the extreme margins of people in the Dallas Heart Study. In quick order, they identified the highest and lowest LDL readings in four groups: black women, black men, white women and white men. They then resequenced the PCSK9 gene in the low-cholesterol groups, looking for mutations that changed the make-up of the protein.

They found seven African Americans with one of two distinct ‘nonsense’ mutations in PCSK9 — mutations that essentially aborted production of the protein. Then they went back and looked for the same mutations in the entire population. Just 2% of all black people in the Dallas study had either of the two PCSK9 mutations — and those mutations were each associated with a 40% reduction of LDL cholesterol in the blood9. (The team later detected a ‘missense mutation’ in 3% of white people, which impaired but did not entirely block production of the protein.) The frequency of the mutations was so low, Hobbs says, that they would never have shown up in a search for common variants.

When Hobbs and Cohen published their findings in 2005, they suggested that PCSK9 played a crucial part in regulating bad cholesterol, but said nothing about whether the mutations had any effect on heart disease. That evidence came later that year, when they teamed up with Eric Boerwinkle, a geneticist at the University of Texas Health Science Center in Houston, to look forPCSK9 mutations in the Atherosclerosis Risk in Communities (ARIC) study, a large prospective study of heart disease that had been running since 1987. To experts such as Steinberg, the results10 — published in early 2006 — were “mind-blowing”. African Americans in ARIC who had mutations in PCSK9 had 28% less LDL cholesterol and an 88% lower risk of developing heart disease than people without the mutations. White people with the less severe mutation in the gene had a 15% reduction in LDL and a 47% reduced risk of heart disease.

How did the gene exert such profound effects on LDL cholesterol levels? As researchers went on to determine11, the PCSK9 protein normally circulates in the bloodstream and binds to the LDL receptor, a protein on the surface of liver cells that captures LDL cholesterol and removes it from the blood. After binding with the receptor, PCSK9 escorts it into the interior of the cell, where it is eventually degraded. When there is a lot of PCSK9 (as in the French families), there are fewer LDL receptors remaining to trap and remove bad cholesterol from the blood. When there is little or no PCSK9 (as in the black people with mutations), there are more free LDL receptors, which in turn remove more LDL cholesterol.

“We didn’t understand why everybody wasn’t doing what we were doing.”

The UT-Southwestern group, meanwhile, went back into the community looking for family members who might carry additional PCSK9 mutations. In September 2004, Gilbert, the nurse known as ‘the cholesterol lady’ in south Dallas because of her frequent visits, knocked on the door of Sharlayne Tracy’s mother, an original member of the Dallas Heart Study. Gilbert tested Tracy, as well as her sister, brother and father. “They tested all of us, and I was the lowest,” Tracy says. Zahid Ahmad, a doctor working with Hobbs at UT-Southwestern, was one of the first to look at Tracy’s lab results. “Dr Zahid was in awe,” Tracy recalled. “He said, ‘You’re not supposed to be so healthy!’.”

It wasn’t just that her LDL cholesterol measured 14. As a person with two dysfunctional copies of the gene — including a new type of mutation — Tracy was effectively a human version of a knockout mouse. The gene had been functionally erased from her genome, and PCSK9 was undetectable in her blood without any obvious untoward effects. The genomics community might have been a little slow to understand the significance, Hobbs says, “but the pharmaceutical companies got it right away”.

The next statin?

This being biology, however, the road to the clinic was not completely smooth. The particular biology of PCSK9 has so far thwarted efforts to find a small molecule that would interrupt its interaction with the LDL receptor and that could be packaged in a pill. But the fact that the molecule operates outside cells means that it is vulnerable to attack by monoclonal antibodies — one of the most successful (albeit most expensive) forms of biological medicine.

The results of early clinical trials have caused a stir. Regeneron Pharmaceuticals of Tarrytown, New York, collaborating with Sanofi, published phase II clinical-trial results12 last October showing that patients with high LDL cholesterol levels who had injections every two weeks of an anti-PCSK9 monoclonal antibody paired with a high-dose statin saw their LDL cholesterol levels fall by 73%; by comparison, patients taking high-dose statins alone had a decrease of just 17%. Last November, Regeneron and Sanofi began to recruit 18,000 patients for phase III trials that will test the ability of their therapy to cut cardiovascular events, including heart attacks and stroke. Amgen of Thousand Oaks, California, has also launched several phase III trials of its own monoclonal antibody after it reported similarly promising results13. Among other companies working on PCSK9-based therapies are Pfizer headquartered in New York, Roche based in Basel, Switzerland, and Alnylam Pharmaceuticals of Cambridge, Massachusetts. (Hobbs previously consulted for Regeneron and Pfizer, and now sits on the corporate board of Pfizer.)

Not everyone is convinced that a huge market awaits this class of cholesterol-lowering drugs. Tony Butler, a financial analyst at Barclays Capital in New York, acknowledges the “beautiful biology” of the PCSK9 story, but wonders if the expense of monoclonal drugs — and a natural reluctance of both patients and doctors to use injectable medicines — will constrain potential sales. “I have no idea what the size of the market may be,” he says.

“Everything hinges on the phase III side effects,” says Steinberg. So far, the main side effects reported have been minor, such as reactions at the injection site, diarrhoea and headaches. But animal experiments have raised potential red flags: the Montreal lab reported in 2006 that knocking out the gene in zebrafish is lethal to embryos14. That is why the case of Tracy was “very, very helpful” to drug companies, says Hobbs. Although her twin mutations have essentially deprived her of PCSK9 throughout her life, doctors have found nothing abnormal about her.

That last point may revive a debate in the cardiology community: should drug therapy to lower cholesterol levels, including statins and the anti-PCSK9 medicines, if they pan out, be started much earlier in patients than their 40s or 50s? That was the message Steinberg took from the people withPCSK9 mutations in the ARIC study — once he got over his shock at the remarkable health effects. “My first reaction was, ‘This must be wrong. How could that be?’And then it hit me — these people had low LDL from the day they were born, and that makes all the difference.” Steinberg argues that cardiologists “should get off our bums” and reach a consensus about beginning people on cholesterol-lowering therapy in their early thirties. But Breslow, a former president of the American Heart Association, cautions against being too aggressive too soon. “Let’s start out with the high-risk individuals and see how they do,” he says.

Not long after Hobbs and Cohen published their paper in 2006, they began to get invited to give keynote talks at major cardiology meetings. Soon after, the genetics community began to acknowledge the strength of their approach. In autumn 2007, then-NIH director Zerhouni organized a discussion at the annual meeting of the institutes’ directors to raise the profile of the rare-variant approach and contrast it with genome-wide studies. “Obviously, the two approaches are opposed to each other, and the question was, what was the relative value of each?” says Zerhouni. “I thought the PCSK9 story was a terrific example of an up-and-coming pattern of translational research” — indeed, he adds, “a harbinger of things to come”.

Hobbs and Cohen might not have found their gene if they had not had a hunch about where to look, but improved sequencing technology and decreasing costs now allow genomicists to incorporate the rare variant approach and to mount large-scale sweeps in search of such variants. “Gene sequencing is getting cheap enough that if there’s another gene like PCSK9 out there, you could probably find it genome-wide,” says Jonathan Pritchard, a population biologist at the University of Chicago, Illinois.

“What was amazing to us,” says Hobbs, “was that the genome project was spending all this time, energy, effort sequencing people, and they weren’t phenotyped, so there was no potential for discovery. We didn’t understand, and couldn’t understand, why everybody wasn’t doing what we were doing. Particularly when we started making discoveries.”

SOURCE:

Nature 496, 152–155 (11 April 2013) doi:10.1038/496152a

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Author information

Affiliations

  1. Stephen S. Hall is a science writer in New York who also teaches public communication to graduate students in science at New York University.

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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.

https://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
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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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Hypertriglyceridemia concurrent Hyperlipidemia: Vertical Density Gradient Ultracentrifugation a Better Test to Prevent Undertreatment of High-Risk Cardiac Patients

Curator: Aviva Lev-Ari, PhD, RN

Equation May Give Wrong LDL Status

By Todd Neale, Senior Staff Writer, MedPage Today

Published: March 28, 2013

Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

  • The widely used Friedewald equation may be underestimating LDL cholesterol levels in many patients, a study found.
  • Note that 14.6% of the patients in the study were placed into different treatment groups by the Friedewald estimates and direct measurements, mainly due to classification in a lower LDL cholesterol treatment group by Friedewald compared with direct LDL cholesterol.

After excluding the patients who had a triglyceride level of 400 mg/dL or greater — in whom there are known limitations of the Friedewald equation — the researchers examined data from 1,310,440 adults (mean age 59) who underwent lipid screening; 14.6% had a Friedewald-estimated LDL cholesterol level of less than 70 mg/dL, the treatment target for high-risk patients.

“Nevertheless, non-HDL cholesterol and apolipoprotein B are alternative approaches, with potential advantages over any measure of LDL cholesterol, and these measures avoid confusion that arises in defining LDL cholesterol …,” they wrote. “Moreover, in clinical trial patients with LDL cholesterol levels in the high-risk range highlighted in our study, non-HDL cholesterol and apolipoprotein B were stronger markers of residual risk than Friedewald LDL cholesterol.”

Martin S, et al “Friedewald estimated versus directly measured low-density lipoprotein cholesterol and treatment implications” J Am Coll Cardiol 2013; DOI: 10.1016/j.jacc.2013.01.079.

VIEW VIDEOBiomarker Series: Lipoprotein A — WellnessFX

VIEW VIDEO BioMarker Series: Apolipoprotein B — WellnessFX

The widely used Friedewald equation may be underestimating LDL cholesterol levels in many patients, researchers found.

The discrepancy between LDL cholesterol values that were estimated by the Friedewald equation and those that were directly measured was greatest when LDL cholesterol levels were low and triglyceride levels were high, according to Seth Martin, MD, of Johns Hopkins Hospital, and colleagues.

Among patients with a Friedewald-estimated value of less than 70 mg/dL, for example, the directly measured level was a median of 9 mg/dL higher when triglycerides were 150 to 199 mg/dL and 18.4 mg/dL higher when triglycerides were 200 to 399 mg/dL, the researchers reported online in the Journal of the American College of Cardiology.

Overall, 14.6% of the patients included in the study were placed into different treatment groups by the Friedewald estimates and direct measurements. This discordance was mainly due to “classification in a lower LDL cholesterol treatment group by Friedewald compared with direct LDL cholesterol,” which occurred in 11.3% of patients, they noted.

The discordance was greatest “when accuracy is most crucial, in patients with LDL cholesterol levels in the high-risk treatment range and concurrent hypertriglyceridemia,” Martin and colleagues wrote, noting that because the Friedewald estimates were generally lower than the directly measured values, using the equation could result in undertreatment of high-risk patients.

“This phenomenon warrants consideration in contemporary patient care and clinical practice guidelines,” the authors wrote.

With the Friedewald equation, LDL cholesterol is estimated by subtracting the HDL cholesterol level and the triglyceride level (divided by 5) from the total cholesterol level. Using the equation avoids the extra time and expense needed to directly measure LDL with ultracentrifugation.

Since the equation was introduced in 1972, however, practice guidelines have introduced lower LDL cholesterol targets, and high triglyceride levels have become more common due to the increasing problems of obesity, insulin resistance, and diabetes.

To assess the accuracy of the equation in a contemporary setting, the researchers compared Friedewald estimates with direct measurements performed with vertical density gradientultracentrifugation by the Vertical Auto Profile (VAP) from 2009 to 2011.

After excluding the patients who had a triglyceride level of 400 mg/dL or greater — in whom there are known limitations of the Friedewald equation — the researchers examined data from 1,310,440 adults (mean age 59) who underwent lipid screening; 14.6% had a Friedewald-estimated LDL cholesterol level of less than 70 mg/dL, the treatment target for high-risk patients.

The median directly measured LDL cholesterol level was 109 mg/dL. Lipid distributions were similar to those seen in the National Health and Nutrition Examination Survey for 2007 to 2008, indicating that the study sample was nationally representative.

In general, the Friedewald estimates were lower than the direct measurements of LDL cholesterol, and the discordance was greatest among patients with low LDL cholesterol levels and high triglyceride levels.

Of the patients with a Friedewald estimate of less than 70 mg/dL, 23% had a direct measurement that was higher than that. That figure rose to 39% when triglycerides were 150 to 199 mg/dL and 59% when triglycerides were 200 to 399 mg/dL.

The findings could have implications for patient care, according to the researchers.

“While we are not suggesting the need for routine clinical measurement of LDL cholesterol by direct assays, it bears mentioning that multiple direct assays beyond the VAP test [used in this study] are available,” they wrote.

“Nevertheless, non-HDL cholesterol and apolipoprotein B are alternative approaches, with potential advantages over any measure of LDL cholesterol, and these measures avoid confusion that arises in defining LDL cholesterol …,” they wrote. “Moreover, in clinical trial patients with LDL cholesterol levels in the high-risk range highlighted in our study, non-HDL cholesterol and apolipoprotein B were stronger markers of residual risk than Friedewald LDL cholesterol.”

They acknowledged some limitations of the analysis, including the possibility that patients who undergo a VAP test may be a special population and the use of one-time LDL cholesterol measurements. In addition, the researchers did not have access to detailed clinical characteristics of the patients or clinical outcomes or information on statin use and fasting status before the lipid test.

http://www.medpagetoday.com/Cardiology/Dyslipidemia/38147?xid=NL_DHE_2013-03-29

REFERENCES

http://my.americanheart.org/professional/General/Secondary-Prevention-Risk-Reduction-for-Cardiac-and-Vascular-Disease_UCM_432926_Article.jsp

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Aspirin for The Prevention of Recurrent Venous Thromboembolism After a First Unprovoked Event: Results of the ASPIRE Randomized Controlled Trial
ASPIRE: This trial is investigating the efficacy of aspirin in preventing recurrent venous thromboembolism (VTE) in patients with first unprovoked VTE

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Main Results of the Future REvascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease (FREEDOM) Trial
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LBCT.02     Health Economics and Quality of Life in Contemporary Trials     Sun., Nov. 4, 2012 / 5:30pm-6:43pm

LBCT.03     Treatments for Prevention of Cardiovascular Events: A Population Perspective     Mon., Nov. 5, 2012 /  9:00am-10:28am

LBCT.04     Novel Treatments for Managing Lipid Disorders     Mon., Nov. 5, 2012 / 10:45am-11:55am

LBCT.05     Cell-Based Therapies for Myocardial Regeneration     Tues., Nov. 6, 2012 / 10:45am-12:00pm

LBCT.06     Management of LV Dysfunction: Devices and Drugs     Tues., Nov. 6, 2012 / 3:45pm-5:35pm

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CS.01     Prevention and Treatment of Ischemic Heart Disease: Novel Approaches     Mon., Nov. 5, 2012 / 7:30am-8:46am

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CS.03     Emerging Therapeutics for Diabetes and Dyslipidemia     Tues., Nov. 6, 2012 / 7:30am-8:25am

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Related articles on this Open Access Online Scientific Journal include the following:

High-Density Lipoprotein (HDL): An Independent Predictor of Endothelial Function & Atherosclerosis, A Modulator, An Agonist, A Biomarker for Cardiovascular Risk 

Aviva Lev-Ari, PhD, RN, 3/31/2013

Artherogenesis: Predictor of CVD – the Smaller and Denser LDL Particles

Aviva Lev-Ari, PhD, RN 11/15/2012

Special Considerations in Blood Lipoproteins, Viscosity, Assessment and Treatment

Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN, 11/28/2012

What is the role of plasma viscosity in hemostasis and vascular disease risk?

Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN, 11/28/2012

Aviva Lev-Ari, PhD, RN, 3/7/2013

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Curator: Aviva Lev-Ari, PhD, RN

Evidence of HDL Modulation of eNOS in Humans

 Whereas the functional link between HDL and eNOS has been appreciated only recently, the relationship between HDL and endothelium-dependent vasodilation has been known for some time. In studies of coronary vasomotor responses to acetylcholine, it was noted in 1994 that patients with elevated HDL have greater vasodilator and attenuated vasoconstrictor responses (Zeiher et al., 1994).

Circulation, 89:2525–2532.

Studies of flow-mediated vasodilation of the brachial artery have also shown that HDL cholesterol is an independent predictor of endothelial function (Li et al., 2000).

Int. J. Cardiol., 73:231–236

Induction of NO Production and Stimulation of eNOS

Mechanism of Action (MOA) for Nitric Oxide (NO) and endothelial Nitric Oxide Syntase (eNOS) are described in George T. and P. Ramwell, (2004). Nitric Oxide, Donors, & Inhibitors. Chapter 19 in Katzung, BG., Basic & Clinical Pharmacology. McGraw-Hill, 9th Edition, pp. 313 – 318

http://books.google.com/books/about/Basic_and_Clinical_Pharmacology.html?id=4O7ghcthkt4C

The direct, short-term impact of HDL on endothelial function also has recently been investigated in humans. One particularly elegant study recently evaluated forearm blood flow responses in individuals who are heterozygous for a loss-of-function mutation in the ATP-binding cassette transporter 1 (ABCA1) gene. Compared with controls, ABCA1 heterozygotes (six men and three women) had HDL levels that were decreased by 60%, their blood flow responses to endothelium-dependent vasodilators were blunted, and endothelium-independent responses were unaltered. After a 4-hour infusion of apoAI/phosphatidylcholine disks, their HDL level increased threefold and endothelium-dependent vasomotor responses were fully restored (Bisoendial et al., 2003). It has also been observed that endothelial function is normalized in hypercholesterolemic men with normal HDL levels shortly following the administration of apoAI/phosphatidylcholine particles (Spieker et al., 2002).

Circulation, 105:1399–1402.

Thus, evidence is now accumulating that HDL is a robust positive modulator of endothelial NO production in humans (Shaul & Mineo, 2004).

J Clin Invest., 15; 113(4): 509–513.

HDL is more than an eNOS Agonist

 In addition to the modulation of NO production by signaling events that rapidly dictate the level of enzymatic activity, important control of eNOS involves changes in the abundance of the enzyme. In a clinical trial by the Karas laboratory of niacin therapy in patients with low HDL levels (nine males and two females), flow-mediated dilation of the brachial artery was improved in association with a rise in HDL of 33% over 3 months (Kuvin et al., 2002).

Am. Heart J., 144:165–172.

They also demonstrated that eNOS expression in cultured human endothelial cells is increased by HDL exposure for 24 hours. They further showed that the increase in eNOS is related to an increase in the half-life of the protein, and that this is mediated by PI3K–Akt kinase and MAPK (Ramet et al., 2003).

J. Am. Coll. Cardiol., 41:2288–2297.

Thus, the same mechanisms that underlie the acute activation of eNOS by HDL appear to be operative in upregulating the expression of the enzyme.

The current understanding of the mechanism by which HDL enhances endothelial NO production is summarized in Shaul & Mineo (2004), Figure 1.

J Clin Invest., 15; 113(4): 509–513.

It describes the mechanism of action for HDL enhancement of NO production by eNOS in vascular endothelium.

(a)   HDL causes membrane-initiated signaling, which stimulates eNOS activity. The eNOS protein is localized in cholesterol-enriched (orange circles) plasma membrane caveolae as a result of the myristoylation and palmitoylation of the protein. Binding of HDL to SR-BI via apoAI causes rapid activation of the nonreceptor tyrosine kinase src, leading to PI3K activation and downstream activation of Akt kinase and MAPK. Akt enhances eNOS activity by phosphorylation, and independent MAPK-mediated processes are additionally required (Duarte, et al., 1997). .Eur J Pharmacol, 338:25–33. HDL also causes an increase in intracellular Ca2+ concentration (intracellular Ca2+ store shown in blue; Ca2+ channel shown in pink), which enhances binding of calmodulin (CM) to eNOS. HDL-induced signaling is mediated at least partially by the HDL-associated lysophospholipids SPC, S1P, and LSF acting through the G protein–coupled lysophospholipid receptor S1P3. HDL-associated estradiol (E2) may also activate signaling by binding to plasma membrane–associated estrogen receptors (ERs), which are also G protein coupled. It remains to be determined if signaling events are also directly mediated by SR-BI (Yuhanna et al., 2001), (Nofer et al., 2004), (Gong et al., 2003), (Mineo et al., 2003).

Nat. Med.7:853–857.

J. Clin. Invest.,113:569–581.

J. Clin. Invest., 111:1579–1587.

J. Biol. Chem., 278:9142–9149.

(b)   HDL regulates eNOS abundance and subcellular distribution. In addition to modulating the acute response, the activation of the PI3K–Akt kinase pathway and MAPK by HDL upregulates eNOS expression (open arrows). HDL also regulates the lipid environment in caveolae (dashed arrows). Oxidized LDL (OxLDL) can serve as a cholesterol acceptor (orange circles), thereby disrupting caveolae and eNOS function. However, in the presence of OxLDL, HDL maintains the total cholesterol content of caveolae by the provision of cholesterol ester (blue circles), resulting in preservation of the eNOS signaling module (Ramet et al., 2003), (Blair et al., 1999), (Uittenbogaard et al., 2000).

J. Am. Coll. Cardiol., 41:2288–2297.

J. Biol. Chem., 274:32512–32519.

J. Biol. Chem., 275:11278–11283.

Source for HDL-eNOS Figure: Shaul & Mineo (2004).

 

HDL enhances NO production by eNOS in vascular endothelium.

FIGURE SOURCE:

Shaul, PW and Mineo, C, (2004). HDL action on the vascular wall: is the answer NO? J Clin Invest., 15; 113(4): 509–513.

eNOS is not Activated by Nebivolol in Human Failing Myocardium.

Nebivolol is a highly selective beta(1)-adrenoceptor blocker with additional vasodilatory properties, which may be due to an endothelial-dependent beta(3)-adrenergic activation of the endothelial nitric oxide synthase (eNOS). beta(3)-adrenergic eNOS activation has been described in human myocardium and is increased in human heart failure. Therefore, this study investigated whether nebivolol may induce an eNOS activation in cardiac tissue. Immunohistochemical stainings were performed using specific antibodies against eNOS translocation and eNOS serine(1177) phosphorylation in rat isolated cardiomyocytes, human right atrial tissue (coronary bypass-operation), left ventricular non-failing (donor hearts) and failing myocardium after application of the beta-adrenoceptor blockers nebivolol, metoprolol and carvedilol, as well as after application of BRL 37344, a specific beta(3)-adrenoceptor agonist. BRL 37344 (10 muM) significantly increased eNOS activity in all investigated tissues (either via translocation or phosphorylation or both). None of the beta-blockers (each 10 muM), including nebivolol, increased either translocation or phosphorylation in any of the investigated tissues. In human failing myocardium, nebivolol (10 muM) decreased eNOS activity. In conclusion, nebivolol shows a tissue-specific eNOS activation. Nebivolol does not activate the endothelial eNOS in end-stage human heart failure and may thus reduce inhibitory effects of NO on myocardial contractility and on oxidative stress formation. This mode of action may be of advantage when treating heart failure patients.

Brixius K, Song Q, Malick A, Boelck B, Addicks K, Bloch W, Mehlhorn U, Schwinger R, (2006). eNOS is not activated by nebivolol in human failing myocardium.

Life Sci. 2006 Apr 25

REFERENCES

Brixius K, Song Q, Malick A, Boelck B, Addicks K, Bloch W, Mehlhorn U, Schwinger R, (2006). eNOS is not activated by nebivolol in human failing myocardium.

Life Sci. 2006 Apr 25

Mineo C, Yuhanna IS, Quon MJ, Shaul PW., (2003). HDL-induced eNOS activation is mediated by Akt and MAP kinases. J. Biol. Chem., 278:9142–9149.

Shaul, PW and Mineo, C, (2004). HDL action on the vascular wall: is the answer NO? J Clin Invest., 15; 113(4): 509–513.

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Artherogenesis: Predictor of CVD – the Smaller and Denser LDL Particles

Reporter: Aviva Lev-Ari, PhD, RN

Updated 3/5/2013

Genetic Associations with Valvular Calcification and Aortic Stenosis

N Engl J Med 2013; 368:503-512

February 7, 2013DOI: 10.1056/NEJMoa1109034

METHODS

We determined genomewide associations with the presence of aortic-valve calcification (among 6942 participants) and mitral annular calcification (among 3795 participants), as detected by computed tomographic (CT) scanning; the study population for this analysis included persons of white European ancestry from three cohorts participating in the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium (discovery population). Findings were replicated in independent cohorts of persons with either CT-detected valvular calcification or clinical aortic stenosis.

CONCLUSIONS

Genetic variation in the LPA locus, mediated by Lp(a) levels, is associated with aortic-valve calcification across multiple ethnic groups and with incident clinical aortic stenosis. (Funded by the National Heart, Lung, and Blood Institute and others.)

SOURCE:

N Engl J Med 2013; 368:503-512

HDL is more than an eNOS Agonist

 In addition to the modulation of NO production by signaling events that rapidly dictate the level of enzymatic activity, important control of eNOS involves changes in the abundance of the enzyme. In a clinical trial by the Karas laboratory of niacin therapy in patients with low HDL levels (nine males and two females), flow-mediated dilation of the brachial artery was improved in association with a rise in HDL of 33% over 3 months (Kuvin et al., 2002).

Am. Heart J., 144:165–172.

They also demonstrated that eNOS expression in cultured human endothelial cells is increased by HDL exposure for 24 hours. They further showed that the increase in eNOS is related to an increase in the half-life of the protein, and that this is mediated by PI3K–Akt kinase and MAPK (Ramet et al., 2003).

J. Am. Coll. Cardiol., 41:2288–2297.

Thus, the same mechanisms that underlie the acute activation of eNOS by HDL appear to be operative in upregulating the expression of the enzyme.

The current understanding of the mechanism by which HDL enhances endothelial NO production is summarized in Shaul & Mineo (2004), Figure 1.

J Clin Invest., 15; 113(4): 509–513.

It describes the mechanism of action for HDL enhancement of NO production by eNOS in vascular endothelium.

(a)   HDL causes membrane-initiated signaling, which stimulates eNOS activity. The eNOS protein is localized in cholesterol-enriched (orange circles) plasma membrane caveolae as a result of the myristoylation and palmitoylation of the protein. Binding of HDL to SR-BI via apoAI causes rapid activation of the nonreceptor tyrosine kinase src, leading to PI3K activation and downstream activation of Akt kinase and MAPK. Akt enhances eNOS activity by phosphorylation, and independent MAPK-mediated processes are additionally required (Duarte, et al., 1997). Eur J Pharmacol, 338:25–33.

HDL also causes an increase in intracellular Ca2+ concentration (intracellular Ca2+ store shown in blue; Ca2+ channel shown in pink), which enhances binding of calmodulin (CM) to eNOS. HDL-induced signaling is mediated at least partially by the HDL-associated lysophospholipids SPC, S1P, and LSF acting through the G protein–coupled lysophospholipid receptor S1P3. HDL-associated estradiol (E2) may also activate signaling by binding to plasma membrane–associated estrogen receptors (ERs), which are also G protein coupled. It remains to be determined if signaling events are also directly mediated by SR-BI (Yuhanna et al., 2001), (Nofer et al., 2004), (Gong et al., 2003), (Mineo et al., 2003).

Nat. Med., 7:853–857.

J. Clin. Invest.,113:569–581.

J. Clin. Invest., 111:1579–1587.

J. Biol. Chem., 278:9142–9149.

(b)   HDL regulates eNOS abundance and subcellular distribution. In addition to modulating the acute response, the activation of the PI3K–Akt kinase pathway and MAPK by HDL upregulates eNOS expression (open arrows). HDL also regulates the lipid environment in caveolae (dashed arrows). Oxidized LDL (OxLDL) can serve as a cholesterol acceptor (orange circles), thereby disrupting caveolae and eNOS function. However, in the presence of OxLDL, HDL maintains the total cholesterol content of caveolae by the provision of cholesterol ester (blue circles), resulting in preservation of the eNOS signaling module (Ramet et al., 2003), (Blair et al., 1999), (Uittenbogaard et al., 2000).

J. Am. Coll. Cardiol., 41:2288–2297.

J. Biol. Chem., 274:32512–32519.

J. Biol. Chem., 275:11278–11283.

SOURCE:

Shaul, PW and Mineo, C, (2004). HDL action on the vascular wall: is the answer NO? J Clin Invest., 15; 113(4): 509–513.

Are Additional Lipid Measures Useful?

Ryan D. Bradley, ND; and Erica B. Oberg, ND, MPH

http://www.imjournal.com/resources/web_pdfs/recent/1208_bradley.pdf

Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are the well-established standards by which clinicians identify individuals at risk for coronary artery disease (CAD), yet nearly 50% of people who have a myocardial infarction have normal cholesterol levels. Measurement of additional biomarkers may be useful to more fully stratify patients according to disease risk. The typical lipid panel includes TC, LDL-C, high-density lipoprotein cholesterol  (HDL-C), and triglycerides (TGs). Emerging biomarkers for cardiovascular risk include measures of LDL-C pattern, size,  and density; LDL particle number; lipoprotein(a); apolipoproteins  (apoA1 and apoB100 being the most useful);  C-reactive protein; and lipoprotein-associated phospholipase

Some of these emerging biomarkers have been proven to add to, or be more accurate than, traditional risk factors in predicting coronary artery disease and, thus, may be useful for clinical decision-making in high-risk patients and in patients with borderline traditional risk factors.  However, we still believe that until treatment strategies can uniquely address these added risk factors—ie, until protocols to rectify unhealthy findings are shown to improve cardiovascular outcomes—healthcare providers should continue to focus primarily on helping patients reach optimal LDL-C, HDL-C, and TG levels

Table 1. Traditional Lipid Panel and Recommended Treatment

Goals for Cardiovascular Disease Prevention34

  • Total Cholesterol Desirable (low) < 200 mg/dL
  • Borderline high 200-239 mg/dL
  • High 240 mg/dL or greater
  • HDL Cholesterol Desirable (high) > 60 mg/dL
  • Acceptable 40-60 mg/dL
  • Low < 40 mg/dL
  • LDL Cholesterol Desirable (low) < 100 mg/dL
  • Acceptable 100-129 mg/dL
  • Borderline high 130-159 mg/dL
  • High 160-189 mg/dL
  • Very high 190 mg/dL or greater
  • Triglycerides Desirable (low) < 150 mg/dL
  • Borderline high 150-199 mg/dL
  • High 200-499 mg/dL
  • Very high 500 mg/dL or greater

LDL-C and HDL-C: Pattern, Size, and Density

Two patterns predominate and are used to describe the average size of LDL particles. Pattern A refers to a preponderance of large LDL particles, while Pattern B refers to a preponderance of small LDL particles; a minority of individuals displays an intermediate or mixed pattern. Some commercially available assays further subdivide LDL-C into 7 distinct designations based on particle size.9,10

LDL Lipoprotein Particle Number

LDL particle number (LDL-P) is a measure of the number of lipoprotein particles independent of the quantity of lipid within the cholesterol particle; ie, LDL-P measures the number of individual particles, not a concentration like LDL-C. It is measured using nuclear magnetic resonance technology and is unaffected by fasting status.21 Higher LDL-P measures have been associated with a higher risk of CAD. This might simply be because there are more particles susceptible to oxidation in circulation.

There are suggestions, but not definitive proof, that reducing LDL-P increases intra-LDL antioxidant capacity.  The European Prospective Investigation of Cancer (EPIC)-Norfolk cohort, a study that has followed 25 663 participants  (men and women aged 45-79 years) over 6 years, evaluated associations between LDL-P and risk of CAD. Compared to controls,  cases of CAD had a higher number of LDL particles (LDL-P P<.0001), smaller average LDL-particle size (P=.002), and higher concentrations of small LDL particles (P<.0001).22

Once again,  small, dense LDL-C were positively associated with TG and negatively associated with HDL.  In another study investigating incident angina and MI with LDL-P, females, but not males, had a significantly increased odds ratio for incident MI and angina for higher LDL-P—but not for LDL size—after adjustment for LDL, age, and race.  Males had increased (but not significant) point estimates showing the same relationship.23 Of note, LDL-P and non-HDL-C (ie,  TC minus HDL-C, or, specifically, LDL-C plus VLDLs), added equivalently to Framingham-predicted CAD risk stratification, thus reducing our enthusiasm for this additional measurement when TC and HDL-C are routinely available.22 Based on these results, LDL-P is becoming recognized as a more-precise measure of LDL-related risk and, as it becomes more available, is likely to replace LDL-C in risk-stratification tools. Clinical availability is currently limited; however, Medicare recently began reimbursing for regular testing of LDL-P in highrisk patients, so we should see availability increase soon. There are no novel treatments based on LDL-P at this time, and data shows therapies that lower LDL-C lower LDL-P as well.

 Apolipoproteins

Apolipoproteins are the protein components of plasma lipoproteins. Several different apolipoproteins have been identified and numbered; however, apoB48, apoB100, and apoA are the most commonly referenced.  ApoB48 is associated with LDL particles that transport dietary cholesterol to the liver for processing. ApoB100 is found in lipoproteins originating from the liver (eg, LDL and VLDL); it transports these lipoproteins and, also, TGs to the periphery. In addition, ApoB100 is involved with the binding of LDL particles to the vascular wall, implicating itself as a key player in the development of atherogenic plaques. Importantly, there is one apoB100 molecule per hepatic-derived lipoprotein. Hence, it is possible to quantify the number of LDL/VLDL particles by noting the total apoB100 concentration.

Measurement of apoB100 has been shown in nearly all studies to outperform LDL-C and non-HDL-C as a predictor of CAD events and as an index of residual CAD risk, perhaps due to differences in measurement sensitivity between measurement methodologies. Direct measurement of apolipoproteins is superior to calculated lipid measurements. Yet, currently, apoB100 measurement is more costly than routine measurements and,  because apoB100 is so closely associated with non-HDL-C (which,  as mentioned previously, can be estimated by TC minus HDL-C),  our enthusiasm for the clinical use of this test is limited.24 For its part, apoA is associated with HDL particles; the 2 major proteins in HDL are apoAI and apoAII. Of these, apoAI has more frequently been used to estimate HDL-C, but, in contrast to apoB100, apoAI is not unique to HDL and so the ratio of apoAI to HDL is not 1 to 1.24

Lipoprotein(a)

Lipoprotein(a)—Lp(a)—is attached to apoB. The association of Lp(a) with CAD and its ability to act as a biomarker of risk appears to be strongest in patients with hypercholesterolemia and, in particular, in young patients with premature atherosclerosis (males younger than 55 and females younger than 65). Part of the reason for this is the observation that there seem to be important threshold effects such that only very high Lp(a) levels (> 30 mg/dL) are associated with elevated vascular risk; in this regard, these increased plasma levels of Lp(a) independently predict the presence of CAD, particularly in patients with elevated LDL-C levels.28

In the Cardiovascular Health Study, a relative risk of approximately 3-fold for death from vascular events and stroke was seen in the highest quintile compared to the lowest quintile of Lp(a) but for males only, whereas no such relation existed for women.29 Lp(a) is commonly considered a marker for familial hypercholesterolemia. Lp(a) may best be used in assessing the risk of younger males with strong family histories of CVD but  should not be used more generally.

Risk Factors for Cardiovascular Disease

(Exclusive of LDL Cholesterol)34

  • Cigarette smoking
  • Hypertension (BP > 140/90 mmHg or on antihypertensive medication)
  • Low HDL cholesterol (< 40 mg/dL)
  • Family history of premature CHD (CHD in first-degree male relative <
  • 55 years; CHD in first-degree female relative < 65 years)
  • Age (men > 44 years; women > 54 years

In addition,

  • Clinical coronary heart disease,
  • symptomatic carotid artery disease,
  • peripheral arterial disease, or
  • abdominal aortic aneurysm

Conclusion

In the United States, treatment guidelines for high CVD risk factors are set by the National Cholesterol Education Program (NCEP) Expert Panel, which developed the third report of the Adult Treatment Panel (ATPIII).34 Treatment goals are determined according to risk stratification by LDL-C and by known additional risk factors such as smoking, low HDL, hypertension,  family history, and age. Yet, clinically, decision-making is always more complex than this. Additional risk stratification can be accomplished by measuring the biomarkers discussed above, and this may potentially provide additive benefit beyond NCEP guidelines. However, we always encourage clinicians to treat known risks to goal levels before adding additional goals for treatment. In a future article we will provide further detail on treatment options for novel biomarkers.

REFERENCES

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2. Tsimikas S, Willerson JT, Ridker PM. C-reactive protein and other emerging blood

biomarkers to optimize risk stratification of vulnerable patients. J Am Coll Cardiol.

2006;47(8 Suppl):C19-C31.

3. Nicholls SJ, Tuzcu EM, Sipahi I, et al. Statins, high-density lipoprotein cholesterol,

and regression of coronary atherosclerosis. JAMA. 2007;297(5):499-508.

4. Hausenloy DJ, Yellon DM. Targeting residual cardiovascular risk: raising high-density

lipoprotein cholesterol levels. JAMA. 2007;297(5):499-508.

5. Bansal S, Buring JE, Rifai N, Mora S, Sacks FM, Ridker PM. Fasting compared with

nonfasting triglycerides and risk of cardiovascular events in women. JAMA.

2007;298(3):309-316.

6. Nordestgaard BG, Benn M, Schnohr P, Tybjaerg-Hansen A. Nonfasting triglycerides

and risk of myocardial infarction, ischemic heart disease, and death in men and

women. JAMA. 2007;298(3):299-308.

7. Stampfer MJ, Krauss RM, Ma J, et al. A prospective study of triglyceride level, lowdensity

lipoprotein particle diameter, and risk of myocardial infarction. JAMA.

1996;276(11):882-888.

8. Ceriello A. The post-prandial state and cardiovascular disease: relevance to diabetes

mellitus. Diabetes Metab Res Rev. 2000;16(2):125-132.

9. Carmena R, Duriez P, Fruchart JC. Atherogenic lipoprotein particles in artherosclerosis.

Circulation. 2004;109(23 Suppl 1):III2-III7.

10. Dormans TP, Swinkels DW, de Graaf J, Hendriks JC, Stalenhoef AF, Demacker PN.

Single-spin density-gradient ultracentrifugation vs gradient gel electrophoresis: two

methods for detecting low-density-lipoprotein heterogeneity compared. Clin Chem.

1991;37(6):853-858.

11. Roheim PS, Asztalos BF. Clinical significance of lipoprotein size and risk for coronary

atherosclerosis. Clin Chem. 1995;41(1):147-152.

12. Swinkels DW, Demacker PN, Hendriks JC, van ‘t Laar A. Low density lipoprotein

subfractions and relationship to other risk factors for coronary artery disease in

healthy individuals. Arteriosclerosis. 1989;9(5):604-613.

13. Tan CE, Chew LS, Chio LF, et al. Cardiovascular risk factors and LDL subfraction

profile in Type 2 diabetes mellitus subjects with good glycaemic control. Diabetes Res

Clin Pract. 2001;51(2):107-114.

14. Lamarche B, Tchernof A, Mauriège P, et al. Fasting insulin and apolipoprotein B levels

and low-density lipoprotein particle size as risk factors for ischemic heart disease.

JAMA. 1998;279(24):1955-1961.

15. St-Pierre AC, Ruel IL, Cantin B, et al. Comparison of various electrophoretic characteristics

of LDL particles and their relationship to the risk of ischemic heart disease.

Circulation. 2001;104(19):2295-2299.

16. Mora S, Szklo M, Otvos JD, et al. LDL particle subclasses, LDL particle size, and

carotid atherosclerosis in the Multi-Ethnic Study of Atherosclerosis (MESA).

Atherosclerosis. 2007;192(1):211-217.

17. Singh IM, Shishehbor MH, Ansell BJ. High-density lipoprotein as a therapeutic target:

a systematic review. JAMA. 2007;298(7):786-798.

18. Lewis GF. Determinants of plasma HDL concentrations and reverse cholesterol

transport. Curr Opin Cardiol. 2006;21(4):345-352.

19. Kontush A, de Faria EC, Chantepie S, Chapman MJ. A normotriglyceridemic, low

HDL-cholesterol phenotype is characterised by elevated oxidative stress and HDL

particles with attenuated antioxidative activity. Atherosclerosis. 2005;182(2):277-285.

20. Nobécourt E, Jacqueminet S, Hansel B, et al. Defective antioxidative activity of small

dense HDL3 particles in type 2 diabetes: relationship to elevated oxidative stress and

hyperglycaemia. Diabetologia. 2005;48(3):529-538.

21. Dungan KM, Guster T, DeWalt DA, Buse JB. A comparison of lipid and lipoprotein

measurements in the fasting and nonfasting states in patients with type 2 diabetes.

Curr Med Res Opin. 2007;23(11):2689-2695.

22. El Harchaoui K, van der Steeg WA, Stroes ES, et al. Value of low-density lipoprotein

particle number and size as predictors of coronary artery disease in apparently

healthy men and women: the EPIC-Norfolk Prospective Population Study. J Am Coll

Cardiol. 2007;49(5):547-553.

23. Kuller L, Arnold A, Tracy R, et al. Nuclear magnetic resonance spectroscopy of lipoproteins

and risk of coronary heart disease in the cardiovascular health study.

Arterioscler Thromb Vasc Biol. 2002;22(7):1175-1180.

24. Olofsson SO, Wiklund O, Borén J. Apolipoproteins A-I and B: biosynthesis, role in

the development of atherosclerosis and targets for intervention against cardiovascular

disease. Vasc Health Risk Manag. 2007;3(4):491-502.

25. Walldius G, Jungner I. Is there a better marker of cardiovascular risk than LDL cholesterol?

Apolipoproteins B and A-I—new risk factors and targets for therapy. Nutr

Metab Cardiovasc Dis. 2007;17(8):565-571.

26. Anand SS, Islam S, Rosengren A, et al. Risk factors for myocardial infarction in

women and men: insights from the INTERHEART study. Eur Heart J.

2008;29(7):932-940.

27. McQueen MJ, Hawken S, Wang X, et al. Lipids, lipoproteins, and apolipoproteins as

risk markers of myocardial infarction in 52 countries (the INTERHEART study): a

case-control study. Lancet. 2008;372(9634):224-233.

28. Danesh J, Collins R, Peto R. Lipoprotein(a) and coronary heart disease. Metaanalysis

of prospective studies. Circulation. 2000;102(10):1082-1085.

29. Ariyo AA, Thach C, Tracy R; Cardiovascular Health Study Investigators. Lp(a) lipoprotein,

vascular disease, and mortality in the elderly. N Engl J Med.

2003;349(22):2108-2115.

30. Retterstol L, Eikvar L, Bohn M, Bakken A, Erikssen J, Berg K. C-reactive protein predicts

death in patients with previous premature myocardial infarction—a 10 year

follow-up study. Atherosclerosis. 2002;160(2):433-440.

31. Kiechl S, Willeit J, Mayr M, et al. Oxidized phospholipids, lipoprotein(a), lipoprotein-

associated phospholipase A2 activity, and 10-year cardiovascular outcomes:

prospective results from the Bruneck study. Arterioscler Thromb Vasc Biol.

2007;27(8):1788-1795.

32. Kolko M, Rodriguez de Turco EB, Diemer NH, Bazan NG. Neuronal damage by

secretory phospholipase A2: modulation by cytosolic phospholipase A2, plateletactivating

factor, and cyclooxygenase-2 in neuronal cells in culture. Neurosci Lett.

2003;338(2):164-168.

33. Robins SJ, Collins D, Nelson JJ, Bloomfield HE, Asztalos BF. Cardiovascular events

with increased lipoprotein-associated phospholipase A(2) and low high-density lipoprotein-

cholesterol: the Veterans Affairs HDL Intervention Trial. Arterioscler Thromb

Vasc Biol. 2008;28(6):1172-1178.

34. Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in

Adults. Executive Summary of The Third Report of The National Cholesterol

Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment

of High Blood Cholesterol In Adults (Adult Treatment Panel III). JAMA.

2001;285(19):2486-2497.

Other related articles on this Open Access Online Scientific Journal include the following:

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

Aviva Lev-Ari, PhD, RN

https://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/

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

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/04/07/cholesteryl-ester-transfer-protein-cetp-inhibitor-potential-of-anacetrapib-to-treat-atherosclerosis-and-cad/

Hypertriglyceridemia concurrent Hyperlipidemia: Vertical Density Gradient Ultracentrifugation a Better Test to Prevent Undertreatment of High-Risk Cardiac Patients

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/04/04/hypertriglyceridemia-concurrent-hyperlipidemia-vertical-density-gradient-ultracentrifugation-a-better-test-to-prevent-undertreatment-of-high-risk-cardiac-patients/

High-Density Lipoprotein (HDL): An Independent Predictor of Endothelial Function & Atherosclerosis, A Modulator, An Agonist, A Biomarker for Cardiovascular Risk

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/03/31/high-density-lipoprotein-hdl-an-independent-predictor-of-endothelial-function-artherosclerosis-a-modulator-an-agonist-a-biomarker-for-cardiovascular-risk/

 

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Reporter: Aviva Lev-Ari, PhD, RN

 

According to The 2012 Johns Hopkins Heart Attack Prevention White Paper by Heart Experts

Roger S. Blumenthal, M.D. 

Director, Johns Hopkins Ciccarone Center for the Prevention of Heart Disease

Professor of Medicine, Johns Hopkins University School of Medicine

and

Simeon Margolis, M.D., Ph.D.

Professor of Medicine and Biological Chemistry

Johns Hopkins University School of Medicine

 

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Find out why a yearly flu shot can protect your heart. You’ll learn about the importance of taming inflammation.

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Evidence linking the flu vaccine to lower heart attack risk.

Angina: A critical warning of heart disease that should never be ignored.

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Since 1889, Johns Hopkins researchers have advanced the development of science and medicine, quickly transferring new knowledge from the research laboratory to the patient’s bedside. The School of Medicine is the largest recipient of biomedical research funds from the National Institutes of Health, and in 2003, Johns Hopkins University’s own Peter Agre, M.D., won the Nobel Prize in chemistry.

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You can trust what you read in The 2012 Johns Hopkins Heart Attack Prevention White Paper. Coauthor Roger S. Blumenthal, M.D., is Professor of Medicine in the Division of Cardiology at The Johns Hopkins Hospital and the Director of the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease. His interests include the development of new strategies to manage coronary heart disease risk factors and the noninvasive detection of coronary atherosclerosis.

Co-author Simeon Margolis, M.D., Ph.D., is Professor of Medicine and Biological Chemistry at the Johns Hopkins University School of Medicine and the medical editor of The Johns Hopkins newsletter, Health After 50.

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The right lifestyle changes can go a long way toward bringing down high blood pressure and cholesterol levels. These simple changes may be enough to let you avoid medication altogether. But if not, making a few well-chosen adjustments in your habits can boost the effectiveness of the medications you take, perhaps even reducing the dosage you require.

How to protect against heart attacks with fiber. Find out if you are getting the recommended daily amount.

What new research reveals about calcium supplements and your risk of coronary heart disease.

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FREE Heart Attack Prevention Special Report: 

Tested, Proven Ways To Save Your Heart

Heart Attack Prevention Strategies

The #1 Way to Prevent a Heart Attack 

The importance of smoking cessation cannot be underestimated.

Walking Your Way to a Healthier Heart 

Johns Hopkins specialists outline the best ways for starting a walking program to maximize your heart health.

Action Plan When a Heart Attack Strikes 

The crucial symptoms to look out for (which can often be different in men and inAs you wi women) and what to do and NOT do if you or a loved one starts to show the telltale signs.

Cholesterol Busting Foods

The latest research on stanols, sterols, soy, fiber, and more.

A Drink a Day for Heart Health?

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Smoking, or living with a smoker, can undermine your best efforts to achieve a healthy heart. Only 5 to 10 percent of people successfully quit on their own, which is why the information in this free gift is so essential. Based on vast clinical experience and knowledge of the full range of medications and techniques to help you quit, Johns Hopkins doctors give you tools that raise your chances of quitting for good.

Learn the three things that, if used in combination, give you a far greater likelihood of kicking the habit.

The latest scientific thinking on nicotine replacement gum, skin patches, nasal sprays and inhalers.

Who’s a candidate for the medications that can help reduce cravings and withdrawal symptoms.

Tips for people who have tried (perhaps many times) before without lasting success.

Why avoiding alcohol can help you avoid cigarettes…

 

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The sooner you take steps to reduce your heart attack risk, the better. Prevention remains your most powerful medicine. But knowing how to respond in an emergency-whether it involves you or someone you are with-can be crucial to survival.

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As you will learn in your free copy of Tested, Proven Ways To Save Your Heart, what you do and what you don’t do during the first crucial minutes and hours following a heart attack can make all the difference in the outcome.

Did you know that a third of all people having a heart attack never experience any chest pain at all? Your Johns Hopkins-designed “Action Plan When a Heart Attack Strikes” alerts you to the range of warning signs, including the less common ones that are more likely to occur in women.

At what point should you call an ambulance? When are you better off driving the person to the hospital instead of waiting for the ambulance to arrive? What information must the emergency personnel have right away? How do you handle the person in denial, who insists, “You’re overreacting” or “There’s nothing wrong?”

I hope you never need to use this information at all. But you’ll be much better prepared to respond calmly and effectively when you have your free gift, Tested, Proven Ways To Save Your Heart, on hand.

SOURCE:

http://www.johnshopkinshealthalerts.com/contact_us/

 

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Cardiovascular Risk Inflammatory Marker: Risk Assessment for Coronary Heart Disease and Ischemic Stroke – Atherosclerosis

Reporter: Aviva Lev-Ari, PhD, RN

 

Updated on 10/3/2018

Treatment concentration of high-sensitivity C-reactive protein

Published:November 13, 2017DOI:https://doi.org/10.1016/S0140-6736(17)32865-9

Interleukin 1β has multiple potential mechanisms that contribute to the pathogenesis of atherothrombotic cardiovascular disease.

Induction of interleukin 6 leads to the release of acute phase reactants including hsCRP. Thus, hsCRP serves as a surrogate marker of the overall inflammatory milieu,

often in situations where patients have multiple co-morbidities,

with a cumulative dose-response indicating a higher risk.

References

  • Ridker PM
  • Everett BM
  • Thuren T
  • et al.
Antiinflammatory therapy with canakinumab for atherosclerotic disease.

N Engl J Med. 2017; 3771119-1131

  • Libby P
Interleukin-1 beta as a target for atherosclerosis therapy: biological basis of CANTOS and beyond.

J Am Coll Cardiol. 2017; 702278-2289

  • Pokharel Y
  • Sharma PP
  • Qintar M
  • et al.
High-sensitivity C-reactive protein levels and health status outcomes after myocardial infarction.

Atherosclerosis. 2017; 26616-23

  • Wang A
  • Liu J
  • Li C
  • et al.
Cumulative exposure to high-sensitivity C-reactive protein predicts the risk of cardiovascular disease.

J Am Heart Assoc. 2017; 6e005610

    • Ridker PM
    • MacFadyen JG
    • Everett BM
    • et al.

on behalf of the CANTOS Trial Group

Relationship of C-reactive protein reduction to cardiovascular event reduction following treatment with canakinumab: a secondary analysis from the CANTOS randomised controlled trial.

Lancet. 2017; (published online Nov 13.)

SOURCE

 

 

 

 

Cardiovascular Risk Inflammatory Marker: Risk Assessment for Coronary Heart Disease and Ischemic StrokeAtherosclerosis.

 

Watch VIDEO

webinar

Lp-PLA2 Overview Webinar

Source: http://www.plactest.com/healthcare/webinar

Watch VIDEO

 american-heart-association-2007-lppla2-highlights

American Heart Association 2007 Lp-PLA2 Presentation

Source: http://www.plactest.com/healthcare/american-heart-association-2007-lppla2-highlights

diaDexus’s PLAC, the test measuting Lp-PLA2 as a novel and valuable cardiovascular risk inflammatory marker a vascular-specific inflammatory marker implicated in the formation of rupture-prone plaque, and is the only blood test cleared by the FDA to assess risk for coronary heart disease and ischemic stroke associated with atherosclerosis. (2003 and in 2005 received additional clearance as an aid in the assessment of risk for ischemic stroke associated with atherosclerosis.)

 

In 2007 the PLAC Test was granted a Category I CPT Code (83698) by the American Medical Association and is reimbursed by the Centers for Medicare and Medicaid Services (CMS) with a National Limitation Amount (NLA) of $47.77 in the 2011 CMS Clinical Laboratory Fee Schedule.

In July 2010, diaDexus completed a reverse merger with VaxGen. diaDexus currently trades on the OTC Bulletin Board (DDXS.OB).

 

PLAC Test is an alternative to C- Reactive Protein Test

 

The PLAC® Test is a simple blood test to detect Lp-PLA2 in the bloodstream. It is used to help predict risk for coronary heart disease and ischemic stroke associated with atherosclerosis.

 

  • The PLAC Test measures Lp-PLA2
    (lipoprotein-associated phospholipase A2), a vascular-specific inflammatory enzyme implicated in the formation of rupture-prone plaque. It is plaque rupture and thrombosis, not stenosis, that causes the majority of cardiac events.
  • A substantial body of evidence, including over 100 studies and abstracts in peer-reviewed journals and conferences, support Lp-PLA2 as a cardiovascular risk marker that provides new information, over and above traditional risk factors.
  • Consistent with ATP III and European guidelines, the PLAC Test should be used as an adjunct to traditional risk factor assessment to identify which moderate or high risk patients, as initially assessed by traditional risk factors, may actually be at higher risk.
  • An elevated PLAC Test may indicate a need for more aggressive patient management.
    • 50% of cardiovascular events strike in patients with unremarkable lipid levels, highlighting the prevalence of hidden cardiovascular risk.
    • LDL-C and total cholesterol have proven not to be reliable predictors of stroke; the PLAC Test addresses this unmet clinical need.
  • Lipid lowering therapies, including statins, are proven to reduce cardiovascular events regardless of baseline LDL-C levels.

 

Basic Science of Lp-PLA2

The PLAC® Test measures Lp-PLA2 (lipoprotein-associated phospholipase A2) a vascular-specific inflammatory enzyme implicated in the formation of rupture-prone plaque. It is plaque rupture and thrombosis that cause the majority of cardiac events, not stenosis.

 

 

 

 

Lp-PLA2 is a calcium-independent serine lipase that is associated with both low-density lipoprotein (LDL) and, to a lesser extent, high-density lipoprotein (HDL) in human plasma and serum and is distinct from other phospholipases such as cPLA2 and sPLA2. Lp-PLA2 is produced by macrophages and other inflammatory cells and is expressed in greater concentrations in advanced atherosclerotic lesions than early-stage lesions.

 

Lp-PLA2 has demonstrated modest intra- and inter-individual variation, commensurate with other cardiovascular lipid markers and substantially less than C-reactive protein (CRP). In addition, Lp-PLA2 is not elevated in systemic inflammatory conditions, and may be a more specific marker of vascular inflammation. The relatively small biological variation of Lp-PLA2 and its specificity are of value in the detection and monitoring of cardiovascular risk.

SOURCE:

http://www.plactest.com/healthcare/basic-science.html

 

 

Clinical Utility of the PLAC Test

 

The PLAC® Test Measures Lp-PLA2, a Unique Marker  
The PLAC Test for Lp-PLA2 is the only blood test cleared by the FDA to aid in assessing risk for both coronary heart disease and ischemic stroke associated with atherosclerosis. The PLAC Test measures lipoprotein-associated phospholipase A2 (Lp-PLA2), a vascular-specific biomarker implicated in the formation of rupture-prone plaque. The majority of all heart attacks and strokes are caused by plaque rupture and thrombosis (clots) – not stenosis (narrowing of arteries).

Lp-PLA2 is a unique marker for vascular-specific inflammation and is produced by macrophages in inflamed plaque. Lp-PLA2 provides additive risk information when combined with other markers such as hs-CRP to help you personalize your treatment options, beyond the limitations of the traditional cardiovascular (CV) risk factors.

The PLAC Test Helps Identify Hidden Risk
Lp-PLA2 is an independent risk marker for stroke. At every level of blood pressure, an Lp-PLA2 value above the median almost doubles the risk for stroke.  Current stroke guidelines include consideration of Lp-PLA2 measurement in asymptomatic patients to identify those who may be at increased risk of stroke.

The PLAC Test Helps Improve Patient Management 
Periodic measurement of the amount of Lp-PLA2 in the blood for patients with 2 or more CVD risk factors can aid clinical decisions for at-risk patients, allowing you to assess or reassess the effect of lipid lowering therapies on vascular inflammation, intensify therapeutic lifestyle changes, and reinforces doctors’ recommendations for patient management.

 

 

 

 

Essential Information to Guide Treatment

In accordance with ATP III Guidelines, patients with 2 or more CV risk factors may be candidates for advanced lipid testing.

Measure the amount of Lp-PLA2 in your patient’s blood stream with the PLAC Test to determine whether they may be at increased risk for heart attack or stroke.

If the PLAC Test results are 200 ng/mL or greater, cardiovascular disease may be present. Review your patient’s advanced lipid panel results to determine where more aggressive patient management may be needed.

 

* additional reduction of Lp-PLA2 seen when added to statin therapy.

Based on:

Shalwitz R, et al. ATVB Annual Mtg. 2007.

Kuvin J, et al. Am J Cardiol. 2006.

Albert M, et al. Atherosclerosis 2005.

Schaefer EJ, et al. Am J Cardiol. 2005.

Saougos VG, et al. ATVB 2007.

Muhlestein JB, et al. JACC 2006.

      Early detection and more aggressive treatment can help prevent cardiovascular events.


 

SOURCE:

http://www.plactest.com/Default.aspx?PageID=4620488&A=PrinterView

 

 

REFERENCES

 

Pathophysiology and Genetics Studies

 

A Twin Study of Heritability of Plasma Lipoprotein-Associated Phospholipase A2 (Lp-PLA2) Mass and ActivityLenzini L, Antezza K, Caroccia B, Wolfert RL, Szczech R, Cesari M, Narkiewicz K, Williams CJ, Rossi GP. A Twin Study of Heritability of Plasma Lipoprotein-Associated Phospholipase A2 (Lp-PLA2) Mass and Activity. Atherosclerosis. 2009; 205(1): 181-5.

Enhanced Expression of Lp-PLA2 and Lysophosphatidylcholine in Symptomatic Carotid Atherosclerotic PlaqueMannheim D, Herrmann J, Versari D, Gössl M, Meyer FB, McConnell JP, Lerman LO, Lerman A. Enhanced Expression of Lp-PLA2 and Lysophosphatidylcholine in Symptomatic Carotid Atherosclerotic Plaque. Stroke. 2008; 39: 1448-55.

Expression of Lipoprotein-Associated Phospholipase A2 in Carotid Artery Plaques Predicts Long-term Cardiac OutcHerrmann J, Mannheim D, Wohlert C, Versari D, Meyer FB, McConnell JP, Gössl M, Lerman LO, Lerman A. Expression of Lipoprotein-Associated Phospholipase A2 in Carotid Artery Plaques Predicts Long-term Cardiac Outcome. Eur. Heart J. 2009 Dec; 30(23): 2930-8.

Lipoprotein-Associated Phospholipase A2 is an Independent Marker for Coronary Endothelial Dysfunction in HumansYang EH, McConnell JP, Lennon RJ, Barsness GW, Pumper G, Hartman SJ, Rihal CS, Lerman LO, Lerman A. Lipoprotein-Associated Phospholipase A2 is an Independent Marker for Coronary Endothelial Dysfunction in Humans. Arterioscler Thromb Vasc Biol. 2006; 26(1): 106-11.

Lipoprotein-Associated Phospholipase A2 Protein Expression in the Natural Progression of Human Coronary AtherosclerosisKolodgie FD, Burke AP, Skorija KS, Ladich E, Kutys R, Makuria AT, Virmani R. Lipoprotein-Associated Phospholipase A2 Protein Expression in the Natural Progression of Human Coronary Atherosclerosis. Arterioscler Thromb Vasc Biol. 2006; 26: 2523-9.

 

Therapeutic Modulation Studies

 

Cardiovascular Events With Increased Lipoprotein-Associated Phospholipase A2 and Low High-Density Lipoprotein-Cholesterol. The Veterans Affairs HDL Intervention Trial.Robins SJ, Collins D, JJ, Bloomfield HE, Asztalos BF. Cardiovascular Events With Increased Lipoprotein-Associated Phospholipase A2 and Low High-Density Lipoprotein-Cholesterol. The Veterans Affairs HDL Intervention Trial. Arterioscler Thromb Vasc Biol. 2008; 28(6): 1172-8.

Changes in Lp-PLA2 activity in secondary prevention predict coronary events and treatment effect by pravastatin in long term intervention with pravastatin in ischemic disease (LIPID) TrialWhite HD, Simes J, Barnes, E et al. Changes in Lp-PLA2 activity in secondary prevention predict coronary events and treatment effect by pravastatin in long term intervention with pravastatin in ischemic disease (LIPID) Trial. Circulation, abstract 14857, AHA 2011

Differential Effect of Hypolipidemic Drugs on Lipoprotein-Associated Phospholipase A2Saougos VG, Tambaki AP, Kalogirou M, Kostapanos M, Gazi IF, Wolfert RL, Elisaf M, Tselepis AD. Differential Effect of Hypolipidemic Drugs on Lipoprotein-Associated Phospholipase A2. Arterioscler Thromb Vasc Biol. 2007; 27: 2236-43.

Effects of Atorvastatin Versus Other Statins on Fasting and Postprandial C-Reactive Protein and Lipoprotein-Associated Phospholipase A2 in Patients With Coronary Heart Disease Versus Control SubjectsSchaefer EJ, McNamara JR, Asztalos BF, Tayler T, Daly JA, Gleason JL, Seman LJ, Ferrari A, Rubenstein JJ. Effects of Atorvastatin Versus Other Statins on Fasting and Postprandial C-Reactive Protein and Lipoprotein-Associated Phospholipase A2 in Patients With Coronary Heart Disease Versus Control Subjects. Am J Cardiol. 2005; 95: 1025-32.

Effects of Extended-Release Niacin on Lipoprotein Particle Size, Distribution, and Inflammatory Markers in Patients With Coronary Artery DiseaseKuvin JT, Dave DM, Sliney KA, Mooney P, Patel AR, Kimmelstiel CD, Karas RH. Effects of Extended-Release Niacin on Lipoprotein Particle Size, Distribution, and Inflammatory Markers in Patients With Coronary Artery Disease. Am J Cardiol. 2006; 98: 743-5.

Cardiovascular Events With Increased Lipoprotein-Associated Phospholipase A2 and Low High-Density Lipoprotein-Cholesterol. The Veterans Affairs HDL Intervention Trial.Robins SJ, Collins D, JJ, Bloomfield HE, Asztalos BF. Cardiovascular Events With Increased Lipoprotein-Associated Phospholipase A2 and Low High-Density Lipoprotein-Cholesterol. The Veterans Affairs HDL Intervention Trial. Arterioscler Thromb Vasc Biol. 2008; 28(6): 1172-8.

Changes in Lp-PLA2 activity in secondary prevention predict coronary events and treatment effect by pravastatin in long term intervention with pravastatin in ischemic disease (LIPID) TrialWhite HD, Simes J, Barnes, E et al. Changes in Lp-PLA2 activity in secondary prevention predict coronary events and treatment effect by pravastatin in long term intervention with pravastatin in ischemic disease (LIPID) Trial. Circulation, abstract 14857, AHA 2011

Differential Effect of Hypolipidemic Drugs on Lipoprotein-Associated Phospholipase A2Saougos VG, Tambaki AP, Kalogirou M, Kostapanos M, Gazi IF, Wolfert RL, Elisaf M, Tselepis AD. Differential Effect of Hypolipidemic Drugs on Lipoprotein-Associated Phospholipase A2. Arterioscler Thromb Vasc Biol. 2007; 27: 2236-43.

Effects of Atorvastatin Versus Other Statins on Fasting and Postprandial C-Reactive Protein and Lipoprotein-Associated Phospholipase A2 in Patients With Coronary Heart Disease Versus Control SubjectsSchaefer EJ, McNamara JR, Asztalos BF, Tayler T, Daly JA, Gleason JL, Seman LJ, Ferrari A, Rubenstein JJ. Effects of Atorvastatin Versus Other Statins on Fasting and Postprandial C-Reactive Protein and Lipoprotein-Associated Phospholipase A2 in Patients With Coronary Heart Disease Versus Control Subjects. Am J Cardiol. 2005; 95: 1025-32.

Effects of Extended-Release Niacin on Lipoprotein Particle Size, Distribution, and Inflammatory Markers in Patients With Coronary Artery DiseaseKuvin JT, Dave DM, Sliney KA, Mooney P, Patel AR, Kimmelstiel CD, Karas RH. Effects of Extended-Release Niacin on Lipoprotein Particle Size, Distribution, and Inflammatory Markers in Patients With Coronary Artery Disease. Am J Cardiol. 2006; 98: 743-5.

Cardiovascular Events With Increased Lipoprotein-Associated Phospholipase A2 and Low High-Density Lipoprotein-Cholesterol. The Veterans Affairs HDL Intervention Trial.Robins SJ, Collins D, JJ, Bloomfield HE, Asztalos BF. Cardiovascular Events With Increased Lipoprotein-Associated Phospholipase A2 and Low High-Density Lipoprotein-Cholesterol. The Veterans Affairs HDL Intervention Trial. Arterioscler Thromb Vasc Biol. 2008; 28(6): 1172-8.

Changes in Lp-PLA2 activity in secondary prevention predict coronary events and treatment effect by pravastatin in long term intervention with pravastatin in ischemic disease (LIPID) TrialWhite HD, Simes J, Barnes, E et al. Changes in Lp-PLA2 activity in secondary prevention predict coronary events and treatment effect by pravastatin in long term intervention with pravastatin in ischemic disease (LIPID) Trial. Circulation, abstract 14857, AHA 2011

Differential Effect of Hypolipidemic Drugs on Lipoprotein-Associated Phospholipase A2Saougos VG, Tambaki AP, Kalogirou M, Kostapanos M, Gazi IF, Wolfert RL, Elisaf M, Tselepis AD. Differential Effect of Hypolipidemic Drugs on Lipoprotein-Associated Phospholipase A2. Arterioscler Thromb Vasc Biol. 2007; 27: 2236-43.

Effects of Atorvastatin Versus Other Statins on Fasting and Postprandial C-Reactive Protein and Lipoprotein-Associated Phospholipase A2 in Patients With Coronary Heart Disease Versus Control SubjectsSchaefer EJ, McNamara JR, Asztalos BF, Tayler T, Daly JA, Gleason JL, Seman LJ, Ferrari A, Rubenstein JJ. Effects of Atorvastatin Versus Other Statins on Fasting and Postprandial C-Reactive Protein and Lipoprotein-Associated Phospholipase A2 in Patients With Coronary Heart Disease Versus Control Subjects. Am J Cardiol. 2005; 95: 1025-32.

Effects of Extended-Release Niacin on Lipoprotein Particle Size, Distribution, and Inflammatory Markers in Patients With Coronary Artery DiseaseKuvin JT, Dave DM, Sliney KA, Mooney P, Patel AR, Kimmelstiel CD, Karas RH. Effects of Extended-Release Niacin on Lipoprotein Particle Size, Distribution, and Inflammatory Markers in Patients With Coronary Artery Disease. Am J Cardiol. 2006; 98: 743-5.

 

 

 

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