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Posts Tagged ‘pharmacotherapy’


Castration Resistant Prostate Cancer

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

Lack of Cumulative Toxicity Associated With Cabazitaxel Use in Prostate Cancer

Di Lorenzo, Giuseppe MD, PhD; Bracarda, Sergio MD; Gasparro, Donatello MD; …; Bosso, Davide MD; Dondi, Davide MSc (Biol); Sonpavde, Guru MD; Lucarelli, Giuseppe MD, PhD; De Placido, Sabino MD, PhD; Buonerba, Carlo MD

Abstract: Cabazitaxel provided a survival advantage compared with mitoxantrone in patients with castration-resistant prostate cancer refractory to docetaxel. Grade 3 to 4 (G3–4) neutropenia and febrile neutropenia were relatively frequent in the registrative XRP6258 Plus Prednisone Compared to Mitoxantrone Plus Prednisone in Hormone Refractory Metastatic Prostate Cancer (TROPIC) trial, but their incidence was lower in the Expanded Access Program (EAP). Although cumulative doses of docetaxel are associated with neuropathy, the effect of cumulative doses of cabazitaxel is unknown. In this retrospective review of prospectively collected data, the authors assessed “per cycle” incidence and predictors of toxicity in the Italian cohort of the EAP, with a focus on the effect of cumulative doses of cabazitaxel.

The study population consisted of 218 Italian patients enrolled in the cabazitaxel EAP. The influence of selected variables on the most relevant adverse events identified was assessed using a Generalized Estimating Equations model at univariate and multivariate analysis.

“Per cycle” incidence of G 3 to 4 neutropenia was 8.7%, whereas febrile neutropenia was reported in 0.9% of cycles. All events of febrile neutropenia occurred during the first 3 cycles. Multivariate logistic regression analysis showed that higher prior dose of cabazitaxel was associated with decreased odds of having G3 to 4 neutropenia (OR = 0.90; 95% CI: 0.86–0.93; P < 0.01), febrile neutropenia (OR = 0.52; 95% CI: 0.34–0.81; P < 0.01) and G3 to 4 anemia (OR = 0.93; 95% CI: 0.86–1; P = 0.07). Patients with a body surface area >2 m2presented increased odds of having G 3 to 4 neutropenia (OR = 0.93; 95% CI: 0.86–1; P = 0.07), but decreased odds of having G3 to 4 anemia.

Among the toxicities assessed, the authors did not identify any that appeared to be associated with a higher number of cabazitaxel cycles delivered. Prior cumulative dose was associated with reduced G3 to 4 neutropenia and anemia. The apparent protective effect associated with higher doses of cabazitaxel is likely to be affected by early dose reduction and early toxicity-related treatment discontinuation. Because this analysis is limited by its retrospective design, prospective trials are required to assess the optimal duration of cabazitaxel treatment.

Several agents provide a survival advantage and symptom palliation in patients with docetaxel-refractory, metastatic castration-resistant prostate cancer (CRPC).1,2 These agents include cabazitaxel, enzalutamide, abiraterone, and radium 223.1,2 Presently, the treatment choice is influenced by several factors, including physician’s and patient’s preference, drug availability, reimbursement policies, performance status, organ function, as well as expected toxicity profile, but comparative efficacy data are lacking. Similarly to other taxane agents, cabazitaxel is frequently associated with bone marrow toxicity. In the XRP6258 Plus Prednisone Compared to Mitoxantrone Plus Prednisone in Hormone Refractory Metastatic Prostate Cancer (TROPIC) trial,3 grade (G) 3–4 neutropenia and febrile neutropenia were reported in 82% and 8% of patients treated with cabazitaxel, respectively, whereas these adverse events were respectively reported in 33.9% and 5% of the Italian patients enrolled in the Expanded Access Program (EAP).4 Conversely, G3 to 4 neuropathy was a rare event both in the TROPIC and in the EAP study.3–5 To further analyze the safety profile of cabazitaxel, we retrospectively reviewed prospectively collected data about the most common toxicities reported in the Italian cohort of the EAP. “Per cycle,” rather than “per patient” incidence was computed, and an explorative analysis was performed to investigate potential predictors of toxicity. In view of the risk of cumulative toxicity (neuropathy) associated with docetaxel,6 the effect of prior cumulative dose of cabazitaxel was investigated in a multivariable model along with other potential predictive factors.

Treatment

At the time of the analysis, 1494 cycles had been administered to 218 patients included in the entire cohort, whereas a total of 553 cycles had been administered to 61 patients with a body surface area >2 sqm. Patients were administered a median of 6.0 (interquartile range: IR, 4–10) cycles. The median dose delivered was 24.00 mg/sqm (IR: 22.3–24.7). Each patient received a median cumulative dose of 149.9 mg/sqm (IR: 92.8–232.2). Sixty-four patients (29.6%) received at least 10 cycles (Table 2). Primary G-CSF prophylaxis was administered in 87 patients (39.9%), whereas G-CSF secondary prophylaxis was administered in 76 patients (34.8%). Therapy was delayed in 274 cycles, which was because of cabazitaxel toxicity only in 65 (23.7%) of these. Dose was reduced 52 times (Table 2), and in 45 cases dose reduction was because of cabazitaxel adverse events. In the safety population, the main reason for treatment discontinuation was disease progression (43.1%), followed by adverse event (24.5%) and physician’s decision (18.5%). Of note, in the subgroup of 64 patients receiving at least 10 cycles, 51.6% discontinued cabazitaxel because of investigator’s decision, and only 1 patient (1.6%) discontinued for toxicity (Table 3).

Table 2
Table 2
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Table 3
Table 3
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Safety

Overall incidence of toxicity per cycle is detailed in Table 4. Main G3 to 4 hematologic toxicities were neutropenia and anemia. The “per cycle” incidence rate of G3 to 4 neutropenia was 8.7%, whereas febrile neutropenia occurred only in 0.9% of all cycles and it was an early event, occurring during the first 3 cycles only (Figure 1). Main non hematologic toxicities were G2 asthenia/fatigue and G2 diarrhea, occurring in 3.7% and 0.8% of cycles, whereas G3 to 4 asthenia/fatigue and G3 to 4 diarrhea occurred in 1.8% and 0.4% of cycles. Four adverse events had a per cycle incidence >1% and were selected for univariate (Tables 5 and 6) and multivariate (Table 7) analysis GEE logistic regression analysis. Febrile neutropenia was also assessed because of its clinical relevance. Multivariate logistic regression analysis showed a significant reduction of the odds of having G3 to 4 neutropenia (−10%), febrile neutropenia (−48%) and anemia (−7%), per 10 mg/m2 increase of total prior dose of cabazitaxel. A body surface area >2 m2 was associated with increased odds of having G3 to 4 neutropenia (OR: 2.58; 95% CI = 1.50–4.43; P < 0.01), but decreased odds of having G3 to 4 anemia (OR: 0.10; 95% CI = 0.02–0.52; P < 0.01). Age as a continuous variable was not associated to an increased rate of any of the adverse events analyzed. Of note, higher previous dose of docetaxel appeared to be associated with a slightly, but statistically significant decreased odds of having G 3–4 anemia (OR: 0.859; 95% CI = 0.73−1.00; P = 0.06), G3 to 4 neutropenia (OR: 0.95; 95% CI = 0.91–0.99; P = 0.03), and G2 and G3 to 4 fatigue/asthenia (OR: 0.90; 95% CI = 0.84–0.96; P < 0.01). Twelve patients died within 30 days since last cabazitaxel treatment for causes judged to be unrelated to cabazitaxel by the local investigators. Three patients died as a result of treatment-emergent adverse events possibly related to cabazitaxel treatment. Of these 3 patients, 1 patient died after 1 cycle because of respiratory and renal failure, 1 patient died after 2 cycles because of respiratory failure and the third patient died after 3 cycles because of pancytopenia and hepatic failure.

Table 4
Table 4
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Figure 1
Figure 1
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Table 5
Table 5
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Table 6
Table 6
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Table 7
Table 7
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DISCUSSION

In a cohort of 746 patients enrolled throughout Europe in the cabazitaxel EAP, G3 to 4 neutropenia, febrile neutropenia and G3 to 4 diarrhea occurred in 17%, 5.4% and 2.8% of patients, respectively.5The discrepancy of these results with those obtained in the TROPIC trial has been explained by study differences in patient characteristics, frequency of hematologic assessment, as well as proactive management of adverse events of cabazitaxel.5 Dose reductions were also more frequent in the EAP compared with the TROPIC trial (17.4% versus 12%) and may also have affected the safety profile.4,5 Furthermore, in the EAP versus the TROPIC trial, 1% versus 2% of patients died as a result of neutropenia, respectively. In our study cohort, only 3 deaths (≈1.3%) possibly related to cabazitaxel treatment were reported, whereas 12 patients died within 30 days since the last cabazitaxel dose for reasons, which were definitely judged to be unrelated to cabazitaxel by the local investigator. Treatment delay, which was reported in 274 cycles, was because of cabazitaxel toxicity approximately only in one-fourth of cases and to “other causes” in 180 cases. This finding may be related to the influence of logistic reasons (eg, waiting list) or patient’s compliance as a common cause of treatment delay. Dose reduction, which was reported in 52 cases, was mainly because of cabazitaxel adverse events. Ongoing phase III trials are assessing whether lower doses of cabazitaxel are equally effective and better tolerated than higher doses.7 In the analysis of our study cohort, the dose of 25 versus 20 mg/m^2 was associated with increased risk of G3 to 4 neutropenia (OR = 1.8; CI = 1.0–3.55; P = 0.049) in the multivariable model, but this result is likely to be confounded by patients who received the 25 mg/m^2 dose and then permanently interrupted treatment for toxicity. Differently from the results obtained in other series,5,8 we have not found the use of G-CSF to be associated with decreased incidence of G3 to 4 neutropenia, possibly because frailer patients are both more likely to experience G 3–4 neutropenia and to receive G-CSF prophylaxis. Similarly to the results obtained in the work by Heidenreich et al,8 we found that prior cumulative dose of docetaxel was associated with lower odds of G3 to 4 neutropenia. Reintroduction of docetaxel was reported to be a feasible option in selected patients, although docetaxel rechallenge is not supported by randomized-controlled trials.9,10 A favorable association of prior cumulative dose of docetaxel with G3 to 4 anemia and G 2–4 asthenia/fatigue was also reported, along with an overall low “per cycle incidence” of febrile neutropenia and G3 to 4 diarrhea and neutropenia. These toxicities do not recur throughout the course of the treatment in most of the cases. Higher prior cumulative dose of cabazitaxel was associated with lower risk of G3 to 4 neutropenia and febrile neutropenia, and the majority of G3 to 4 events of bone marrow toxicity occurred during the first 5 cycles. Heidenreich et al5 compared toxicities associated with first versus subsequent doses and reported higher odds of severe neutropenia at the first cycle versus subsequent cycles. This result is consistent with existing data.11 In our work, we found no evidence of cumulative toxicity for any of the adverse events considered in a multivariable model assessing their association with prior cumulative dose of cabazitaxel. In this regard, it is noteworthy that of the 64 patients receiving at least 10 cycles, only 1 (1.5%) had to interrupt treatment because of toxicity and approximately 50% (33 patients, 51.6%) suspended treatment because of investigator’s decision. Although continuation of docetaxel after 10 cycles does not appear to yield any benefit,12 the optimal duration of cabazitaxel treatment in nonprogressive patients is unknown.

No studies have been specifically conducted to assess the additional benefit associated with continuation of cabazitaxel treatment beyond 10 cycles. Nevertheless, the risk of rapidly progressive disease following cabazitaxel interruption must be carefully considered and discussed with the patient, especially in those with high disease burden who may experience clinical deterioration and be unable to resume systemic therapy.13 We also reported that patients with a body surface area greater than 2 m2 showed an OR of 2.58 for G3 to 4 neutropenia, but an OR of 0.1 for G3 to 4 anemia. We are unable to provide an explanation for this finding at the present time.

Our analysis has a number of limitations, including its retrospective nature, the arbitrary selection of the variables included in the multivariable model, the lack of sample size calculation, as well as the lack of assessment of peripheral neuropathy, which is a clinically relevant adverse event in patients receiving chemotherapy after first-line docetaxel6,14. Furthermore, the number of patients receiving >10 cycles was small and no patient received more than 17 cycles. In this regard, it must be noted that a report of 4 patients with CRPC cancer treated with >15 cycles of cabazitaxel found that peripheral neuropathy was the only clinically significant toxicity associated with cumulative doses.15 There is no established clinical variable predictive of cabazitaxel efficacy in the postdocetaxel setting, although preliminary evidence by our work group suggest that cabazitaxel could be more effective than novel hormonal agents in a number of clinical settings, which include patients with brain metastases,16 high Gleason score at diagnosis,17 and primary refractoriness to docetaxel.18 Similarly to other antineoplastic agents (eg, sunitinib19), cabazitaxel may also be more effective in patients showing greater treatment-related toxicity. A recent post-hoc analysis of the TROPIC trial suggested that treatment outcomes, in terms of Overall Survival, Progression Free Survival, and Prostate Specific Antigen response, were improved in patients developing G3 to 4 neutropenia.20 Our analysis confirms that the safety profile of cabazitaxel compares favorably with that of docetaxel, which was associated with G3 to 4 diarrhea, nail changes, and peripheral neuropathy in approximately 30% of the patients.21 Among the toxicities assessed, we did not identify any that appeared to be dependent on the cumulative dose of cabazitaxel priorly administered. As this finding is likely to be influenced by early dose reduction and early toxicity-related treatment discontinuation, it must be confirmed by prospective larger trials in patients with metastatic castration resistant prostate cancer.

REFERENCES

1. Omlin A, Pezaro C, Mukherji D, et al. Improved survival in a cohort of trial participants with metastatic castration-resistant prostate cancer demonstrates the need for updated prognostic nomograms. Eur Urol 2013; 64:300–306.

2. Rescigno P, Buonerba C, Bellmunt J, et al. New perspectives in the therapy of castration resistant prostate cancer. Curr Drug Targets 2012; 13:1676–1686.

3. de Bono JS, Oudard S, Ozguroglu M, et al. Prednisone plus cabazitaxel or mitoxantrone for metastatic castration-resistant prostate cancer progressing after docetaxel treatment: a randomised open-label trial. Lancet 2010; 376:1147–1154.

4. Bracarda S, Gernone A, Gasparro D, et al. Real-world cabazitaxel safety: the Italian early-access program in metastatic castration-resistant prostate cancer. Future Oncol 2014; 10:975–983.

5. Heidenreich A, Bracarda S, Mason M, et al. Safety of cabazitaxel in senior adults with metastatic castration-resistant prostate cancer: results of the European compassionate-use programme. Eur J Cancer 2014; 50:1090–1099.

6. Oudard S, Kramer G, Caffo O, et al. Docetaxel rechallenge after an initial good response in patients with metastatic castration-resistant prostate cancer. BJU Int 2015; 115:744–752.

7. Suzman DL, Antonarakis ES. Castration-resistant prostate cancer: latest evidence and therapeutic implications. Ther Adv Med Oncol 2014; 6:167–179.

8. Di Lorenzo G, D’Aniello C, Buonerba C, et al. Peg-filgrastim and cabazitaxel in prostate cancer patients. Anticancer Drugs 2013; 24:84–89.

9. Di Lorenzo G, Buonerba C, Faiella A, et al. Phase II study of docetaxel re-treatment in docetaxel-pretreated castration-resistant prostate cancer. BJU Int 2011; 107:234–239.

10. Buonerba C, Palmieri G, Di Lorenzo G. Docetaxel rechallenge in castration-resistant prostate cancer: scientific legitimacy of common clinical practice. Eur Urol 2010; 58: 636-.

11. Culakova E, Thota R, Poniewierski MS, et al. Patterns of chemotherapy-associated toxicity and supportive care in US oncology practice: a nationwide prospective cohort study. Cancer Med 2014; 3:434–444.

12. Pond GR, Armstrong AJ, Wood BA, et al. Evaluating the value of number of cycles of docetaxel and prednisone in men with metastatic castration-resistant prostate cancer. Eur Urol 2012; 61:363–369.

13. Di Lorenzo G, Buonerba C, de Placido S. Rapidly progressive disease in a castration-resistant prostate cancer patient after cabazitaxel discontinuation. Anticancer Drugs 2015; 26:236–239.

14. Buonerba C, Federico P, D’Aniello C, et al. Phase II trial of cisplatin plus prednisone in docetaxel-refractory castration-resistant prostate cancer patients. Cancer Chemother Pharmacol 2011; 67:1455–1461.

15. Noronha V, Joshi A, Prabhash K. Beyond ten cycles of cabazitaxel for castrate-resistant prostate cancer. Indian J Cancer 2014; 51:363–365.

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Calcium Channel Blocker Potential for Angina

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

 

Pranidipine    

ANTHONY MELVIN CRASTO, PhD

str1

https://newdrugapprovals.files.wordpress.com/2015/12/str116.jpg

 

File:Pranidipine structure.svg

Pranidipine , OPC-13340, FRC 8411

Acalas®

NDA Filing in Japan

A calcium channel blocker potentially for the treatment of angina pectoris and hypertension.

 

CAS No. 99522-79-9

  • Molecular FormulaC25H24N2O6
  • Average mass 448.468

 

see dipine series………..http://organicsynthesisinternational.blogspot.in/p/dipine-series.html

manidipine

 

PAPER

Der Pharmacia Sinica, 2014, 5(1):11-17

https://newdrugapprovals.files.wordpress.com/2015/12/str113.jpg

pelagiaresearchlibrary.com/der-pharmacia-sinica/vol5-iss1/DPS-2014-5-1-11-17.pdf

 

Names
IUPAC name

methyl (2E)-phenylprop-2-en-1-yl 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate
Other names

2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid O5-methyl O3-[(E)-3-phenylprop-2-enyl] ester
Identifiers
99522-79-9 Yes
ChEMBL ChEMBL1096842 
ChemSpider 4940726 
Jmol interactive 3D Image
MeSH C048161
PubChem 6436048
UNII 9DES9QVH58 Yes

 

 

 

PATENT SUBMITTED GRANTED
Process for the preparation of 1,4 – dihydropyridines and novel 1,4-dihydropyridines useful as therapeutic agents [US2003230478] 2003-12-18
Advanced Formulations and Therapies for Treating Hard-to-Heal Wounds [US2014357645] 2014-08-19 2014-12-04
METHODS OF TREATING CARDIOVASCULAR AND METABOLIC DISEASES [US2014322199] 2012-08-06 2014-10-30
Protein Carrier-Linked Prodrugs [US2014323402] 2012-08-10 2014-10-30
sGC STIMULATORS [US2014323448] 2014-04-29 2014-10-30
TREATMENT OF ARTERIAL WALL BY COMBINATION OF RAAS INHIBITOR AND HMG-CoA REDUCTASE INHIBITOR [US2014323536] 2012-12-07 2014-10-30
Agonists of Guanylate Cyclase Useful For the Treatment of Gastrointestinal Disorders, Inflammation, Cancer and Other Disorders [US2014329738] 2014-03-28 2014-11-06
METHODS, COMPOSITIONS, AND KITS FOR THE TREATMENT OF CANCER [US2014335050] 2012-05-25 2014-11-13
ROR GAMMA MODULATORS [US2014343023] 2012-09-18 2014-11-20
High-Loading Water-Soluable Carrier-Linked Prodrugs [US2014296257] 2012-08-10 2014-10-02 

 

 

Synthesis, isolation and use of a common key intermediate for calcium antagonist inhibitors

Neelakandan K.a,b, Manikandan H.b , B. Prabhakarana*, Santosha N.a , Ashok Chaudharia *, Mukund Kulkarnic , Gopalakrishnan Mannathusamyb and Shyam Titirmarea
a API Research Centre, Emcure Pharmaceutical Limited, Hinjawadi, Pune, India bDepartment of Chemistry, Annamalai University, Chidhambaram, India cDepartment of Chemistry, Pune University, Pune, India _________________________________________________________________________________

Pelagia Research Library     www.pelagiaresearchlibrary.com      Der Pharmacia Sinica, 2014, 5(1):11-17

 

The compound (3) synthesized from Nitrobenzaldehyde, tertiary butyl acetoacetate and piperidine can be used as a common intermediate for the production of calcium channel blockers like Nicardipine hydrochloride (1) and Pranidipine hydrochloride (2) with high purity.

 

The last twenty years have witnessed discoveries of calcium antagonists associated with multicoated pharmacodynamics potential which include not only antihypertensive and antiarrhythmic effects of the drugs but also action against excessive calcium entry in the cell of cardiovascular system and subsequent cell damage. Among many classes of calcium channel blockers, 1,4-dihydropyrimidine based drug molecules represented by Felodipine, Clevidipine, Benidipine, Nicardipine and Pranidipine are by far the best to reduce systemic vascular resistance and arterial pressure.

The reported synthetic approaches however proceed with complicated work ups, laborious purification procedures, highly expensive chemicals and low overall yields. (Scheme-I).

Synthetic scheme of Nicardipine and Pranidipine In view of the draw backs associated with previous synthetic approaches there is a strong need for environmentfriendly high yielding process applicable to the multi-kilogram production of calcium antagonist inhibitors. Herein, we report a scalable synthesis for Nicardipine hydrochloride (1) and Pranidipine hydrochloride (2) in fairly high overall yield using key intermediate 3-nitro benzylidene acid (3).Compound (3) was synthesized in two steps using 3-nitrobenzaldehyde, tertiary butyl acetoacetate and piperidine as a base to furnish tertiary butyl ester derivative (10). This was followed by hydrolysis of (10) in TFA and DCM to furnish compound (3) which would serve as a precursor for synthesis of versatile calcium antagonist inhibitors (Scheme-II).

Reported routes for synthesis of Benidipine,1,2 Lercanadipine,3-6 Nimodipine,7-11 Barnidipine12-14 and Manidipine15-16 were explored in our laboratory which involve reaction of nitro benzaldehyde with tertiary butyl acetoacetate using piperidine as a base to get tertiary butyl ester derivative (10). This is further treated with respective reagents to get various calcium channel blockers as shown in scheme 4. Since reported procedures involve in-situ generation of intermediate (3) and its reaction with corresponding fragments, it results in the formation of by-products which ultimately decrease the yield and increase the cost of API.

A novel process of manufacturing benzylidine acid derivative (3) was developed. Use of this intermediate was demonstrated by synthesis of Nicardipine and Pranidipine. This protocol may be employed for synthesis of other calcium channel blockers. In conclusion, a highly efficient, reproducible and scalable process for the synthesis of calcium channel blockers has been developed using (3) as the key intermediate.

 

[1] US 63 365 (Kyowa Hakko; appl.15.4.1982; J-prior.17.4.1981). [2] US 4 448 964 (Kyowa Hakko;15.5.1984; J-prior.17.4.1981). [3] Leonardi, A. et al.: Eur. J. Med.Chem. (EJMCA5) 33,399 (1988). [4] EP 153 016 (Recordati Chem. and Pharm.; appl. 21.1.1985; GB-prior. 14.2.1984). [5] US 4 705 797 (Recordati;10.11.1987; GB-prior. 14.2.1984). [6] WO 9 635 668 (Recordati Chem. and Pharm.; appl. 9.5.1996; I-prior. 12.5.1995). [7] DOS 2 117 571 (Bayer; appl. 10.4.1971). [8] DE 2 117 573 (Bayer; prior.10.4.1971) [9] US 3 799 934 (Bayer;26.3.1974;D-prior.10.4.1971). [10] US 3 932 645 (Bayer;13.1.1976;D-prior.10.4.1971). [11] Meyer, H. et al.: Arzneim.-Forsch. (ARZNAD) 31, 407 (1981); 33, 106 (1983). [12] DE 2 904 552 (Yamanouchi Pharm.; appl. 7.2.1979; J-prior.14.2.1978). [13] US 4 220 649 (Yamanouchi;2.9.1980; J-prior.14.2.1978). [14] CN 85 107 590( Faming Zhuanli Sheqing Gonhali S.; appl. 11.10.1985; J-prior.24.1.1985). [15] EP 94 159 (Takeda; appl. 15.4.1983; J-prior. 10.5.1982). [16] US 4 892 875 (Takeda;9.1.1990; J-prior. 10.5.1982, 11.1.1983).

 

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Diabetes Mellitus

Author & Curator: Larry H. Bernstein, MD, FCAP

 

Diabetes mellitus (DM) is a group of metabolic diseases defined by high blood glucose levels, which, depending on the fasting blood glucose, may be pre-diabetes or overt diabetes (110 mg/dl. 124 mg/dl). This blood glucose level reflects a disorder of control of glucose metabolism, which is mediated through the pituitary growth hormone acting on the liver, which produces insulin growth factor 1 (IGF1).  Diabetes is due to either the pancreas not producing enough insulin, or the cells of the body not responding properly to the insulin produced. That said, there is much to be understood about the long term systemic effects of this disorder, a multisystem disease. The presence of pre-diabetes glucose levels is sufficient to proactively take measures to reduce the circulating glucose.

Globally, as of 2013, an estimated 382 million people have diabetes worldwide, with type 2 diabetes making up about 90% of the cases. This is equal to 8.3% of the adults population, with equal rates in both women and men. Worldwide in 2012 and 2013 diabetes resulted in 1.5 to 5.1 million deaths per year, making it the 8th leading cause of death. Diabetes overall at least doubles the risk of death. The number of people with diabetes is expected to rise to 592 million by 2035. The economic costs of diabetes globally was estimated in 2013 at $548 billion and in the United States in 2012 $245 billion.

The observation of symptoms of frequent urination, increased thirst, and increased hunger is symptomatic of overt DM, and is seen with diabetic ketoacidosis, with very high hyperglycemia and glucosuria, particularly in Type 1 DM. Untreated, diabetes leads to serious complications. Acute complications include diabetic ketoacidosis. Serious long-term complications include heart disease, stroke, kidney failure, foot ulcers and damage to the eyes.

There are three main types of diabetes mellitus:

  • Type 1 DM results from the body’s failure to produce enough insulin. This form was previously referred to as “insulin-dependent diabetes mellitus” (IDDM) or “juvenile diabetes”. The cause is unknown.
  • Type 2 DM begins with insulin resistance, a condition in which cells fail to respond to insulin properly. As the disease progresses a lack of insulin may also develop. This form was previously referred to as “non insulin-dependent diabetes mellitus” (NIDDM) or “adult-onset diabetes”. The primary cause is excessive body weight and not enough exercise.
  • Gestational diabetes, the third, occurs when pregnant women without a previous history of diabetes develop a high blood glucose level.

Type 1 DM, which presents suddenly in children or young adults, is possibly an as yet unidentified post-translational or epigenetic form, unrelated to Type 2, which is becoming more common in children.  It results in the destruction of islet beta cells that then have no capacity to produce insulin.  A family history of the disease would be a signal to raise a child with great care to not stress the pancreas.  Even though I raised the possibility of an epigenetic factor, it is important to keep in mind that the regulation of glucose is responsive to a number of stresses, even in a healthy person.  These are:

  • Corticosteroids
  • Glucagon
  • Growth hormone
  • Catecholamines
  • Proinflammatory cytokines
  • Anxiety disorder
  • Eating disorder

Gestational diabetes is perhaps Type 2 diabetes in a pregnant woman initiated by the condition of pregnancy. Whether these women were not diabetic, with a glucose level between 100-110 prior to pregnancy, is an open question. However, the pregnant state is accompanied by large effects by hormone levels.

Type 2 diabetes has been increasing worldwide, not only in western nations.  However, in non-western countries that have large populations of underserved, there is still a major problem with protein energy malnutrition (PEM). Globally, as of 2013, an estimated 382 million people have diabetes worldwide, with type 2 diabetes making up about 90% of the cases. This is equal to 8.3% of the adults population, with equal rates in both women and men. Worldwide in 2012 and 2013 diabetes resulted in 1.5 to 5.1 million deaths per year, making it the 8th leading cause of death. Diabetes overall at least doubles the risk of death. The number of people with diabetes is expected to rise to 592 million by 2035. The economic costs of diabetes globally was estimated in 2013 at $548 billion and in the United States in 2012 $245 billion.

The major long-term complications relate to damage to blood vessels. Diabetes doubles the risk of cardiovascular disease and about 75% of deaths in diabetics are due to coronary artery disease. Other “macrovascular” diseases are stroke, and peripheral vascular disease. The primary microvascular complications of diabetes include damage to the eyes, kidneys, and nerves. Damage to the eyes, known as diabetic retinopathy, is caused by damage to the blood vessels in the retina of the eye, and can result in gradual vision loss and potentially blindness. Damage to the kidneys, known as diabetic nephropathy, can lead to tissue scarring, urine protein loss, and eventually chronic kidney disease, sometimes requiring dialysis or kidney transplant. Damage to the nerves of the body, known as diabetic neuropathy, is the most common complication of diabetes.

Prevention and treatment involves a healthy diet, physical exercise, not using tobacco and being a normal body weight. Blood pressure control and proper foot care are also important for people with the disease. Type 1 diabetes must be managed with insulin injections. Type 2 diabetes may be treated with medications with or without insulin. Insulin and some oral medications can cause low blood sugar. Weight loss surgery in those with obesity is an effective measure in those with type 2 DM. Gestational diabetes usually resolves after the birth of the baby.

A number of articles in http://pharmaceuticalintelligence,com (this journal) have presented the relationship of DM to heart and vascular disease. The complexity of the disease is not to be underestimated, and there havr been serious controversies with adverse consequences over the use of the class of drugs that includes rosiglitazone and piaglitazone, which has opened serious issues about how clinical trials are conducted, and how the data obtained in studies may be compromised.

Pharmaceutical Insights

Management of Diabetes Mellitus: Could Simultaneous Targeting of Hyperglycemia and Oxidative Stress Be a Better Panacea?

Omotayo O. Erejuwa
Int. J. Mol. Sci. 2012, 13, 2965-2972; http://www.mdpi.com/journal/ijms http://dx.doi.org:/10.3390/ijms13032965

The primary aim of the current management of diabetes mellitus is to achieve and/or maintain a glycated hemoglobin level of ≤6.5%. However, recent evidence indicates that intensive treatment of hyperglycemia is characterized by increased weight gain, severe hypoglycemia and higher mortality. Besides, evidence suggests that it is difficult to achieve and/or maintain optimal glycemic control in many diabetic patients; and that the benefits of intensively-treated hyperglycemia are restricted to microvascular complications only. Evidence also indicates that multiple drugs are required to achieve optimal glycemic target in many diabetic patients. In fact, in many diabetic patients in whom optimal glycemic goal is achieved, glycemic control deteriorates even with optimal drug therapy. It does suggest that with the current hypoglycemic or antidiabetic drugs, it is difficult to achieve and/or maintain tight glycemic control in diabetic patients. In many developing countries, the vast majority of diabetic patients have limited or lack access to quality healthcare providers and good therapeutic monitoring.

While increased weight gain could be due to some component drugs (such as sulphonylureas or insulin) of the intensive therapy regimens, hypoglycemia could be drug-induced or comorbidity-induced. Considering the evidence that associates hypoglycemia with increased mortality, higher incidence of mortality in intensive therapy group could be due to hypoglycemia or too low levels of glycosylated hemoglobin. However, it is difficult to contend that increased mortality was entirely due to hypoglycemia. The possibility of drug-induced or drug-associated toxicities could not be ruled out. For instance, rosiglitazone, which has been prohibited and withdrawn from the market in Europe, was one of the hypoglycemic drugs used to achieve intensive therapy of hyperglycemia in Action to Control Cardiovascular Risk in Diabetes (ACCORD). If these findings are anything to go by, does it not suggest that targeting hyperglycemia as the only therapeutic goal in the management of diabetes mellitus could be detrimental to diabetic patients? In addition, the current hypoglycemic drugs are characterized by limitations and adverse effects. Together with the limitations of intensive glycemic treatment (only beneficial in reducing the risk of microvascular complications, but not macrovascular disease complications), does it not imply that targeting hyperglycemia alone is not only deleterious but also limited and ineffective?

The latest figures predict that the global incidence of diabetes mellitus, which was estimated to be 366 million in 2011, will rise to 522 million by 2030. In view of these frightening statistics on the prevalence of diabetes mellitus and on the lack of adequate healthcare, together with the associated diabetic complications, morbidity and mortality, does it not suggest that there is an urgent need for a better therapeutic management of this disorder? Taken together, with these findings and statistics, it can be contended that it is high time alternative and/or complementary therapies to the currently available hypoglycemic agents (which target primarily hyperglycemia only) were sought.

All these may contribute to the unabated increase in global prevalence of diabetes mellitus and its complications In view of these adverse effects and limitations of intensive treatment of hyperglycemia in preventing diabetic complications, which is linked to oxidative stress,

  • this commentary proposes a hypothesis that “simultaneous targeting of hyperglycemia and oxidative stress” could be more effective than “intensive treatment of hyperglycemia” in the management of diabetes mellitus.

Oxidative stress is defined as

  • an “imbalance between oxidants and antioxidants in favor of the oxidants, potentially leading to damage”.

It is implicated in the pathogenesis and complications of diabetes mellitus. The role of oxidative stress is more definite in the pathogenesis of type 2 diabetes mellitus than in type 1 diabetes mellitus. In regard to diabetic complications, there is compelling evidence in support of the role of oxidative stress in both types of diabetes mellitus. Evidence suggests that elevated reactive oxygen species (ROS), which causes factor of increased ROS production, causes tissue damage or diabetic complications have been identified. These include:

  • hyperglycemia-enhanced polyol pathway;
  • hyperglycemia-enhanced formation of advanced glycation endproducts (AGEs);
  • hyperglycemia-activated protein kinase C (PKC) pathway;
  • hyperglycemia-enhanced hexosamine pathway; and
  • hyperglycemia-activated Poly-ADP ribose polymerase (PARP) pathway.

These pathways are activated or enhanced by hyperglycemia-driven mitochondrial superoxide overproduction.

Even though oxidative stress plays an important role in its pathogenesis and complications,

  • unlike other diseases characterized by oxidative stress, diabetes mellitus is unique.

Its cure (restoration of euglycemia, e.g., via pancreas transplants) does not prevent oxidative stress and diabetic complications. This is very important because hyperglycemia exacerbates oxidative stress which is linked to diabetic complications. Theoretically, restoration of euglycemia should prevent oxidative stress and diabetic complications. However, this is not the case. At present, it remains unclear why restoration of euglycemia does not automatically prevent oxidative stress and diabetic complications. The development of diabetes-related complications (both microvascular and macrovascular) may occur in diabetic patients after normoglycemia has been restored. It is a phenomenon whereby previous hyperglycemic milieu is remembered in many target organs such as heart, eyes, kidneys and nerves. This phenomenon is also documented in diabetic animals. Compelling evidence implicates the role of oxidative stress as an important mechanism by which glycemic memory causes tissue damage and diabetic complications. In view of higher incidence of diabetic complications (of which oxidative stress plays an important role) in conventionally-treated diabetic patients, targeting oxidative stress in these patients might be beneficial. In other words, it is possible that the combination of a conventional therapy of hyperglycemia and antioxidant therapy might be more effective and beneficial than intensive therapy of hyperglycemia alone, which is the gold standard at the moment.

Loss of ACE 2 Exaggerates High-Calorie Diet-Induced Insulin Resistance by Reduction of GLUT4 in Mice

M Takeda, K Yamamoto, Y Takemura, H Takeshita, K Hongyo, et al.  Diabetes 61:1–11, 2012

ACE type 2 (ACE2) functions as

  • a negative regulator of the renin angiotensin system
  • by cleaving angiotensin II (AII) into angiotensin 1–7 (A1–7).

This study assessed the role of

  • endogenous ACE2 in maintaining insulin sensitivity.

Twelve-week-old male ACE2 knockout (ACE2KO) mice had normal insulin sensitivities when fed a standard diet. AII infusion or a high-fat high-sucrose (HFHS) diet impaired glucose tolerance and insulin sensitivity more severely

  • in ACE2KO mice than in their wild-type (WT) littermates.

The strain difference in glucose tolerance

  • was not eliminated by an AII receptor type 1 (AT1) blocker
  • but was eradicated by A1–7 or an AT1 blocker combined with the A1–7 inhibitor (A779).

The expression of GLUT4 and a transcriptional factor, myocyte enhancer factor (MEF) 2A,

  • was dramatically reduced in the skeletal muscles of the standard diet–fed ACE2KO mice.

The expression of GLUT4 and MEF2A was increased

  • by A1–7 in ACE2KO mice and
  • decreased by A779 in WT mice.

A1–7 enhanced upregulation of MEF2A and GLUT4 during differentiation of myoblast cells. In conclusion,

  • ACE2 protects against high calorie diet-induced insulin resistance in mice.

This mechanism may involve the transcriptional regulation of GLUT4 via an A1–7-dependent pathway.
Modulation of the action of insulin by angiotensin-(1–7)
FP. Dominici, V Burghi, MC. Munoz, JF. Giani

Clinical Science (2014) 126, 613–630 http://dx.doi.org:/10.1042/CS20130333

The prevalence of Type 2 diabetes mellitus is predicted to increase dramatically over the coming years and the clinical implications and healthcare costs from this disease are overwhelming. In many cases, this pathological condition is linked to a cluster of metabolic disorders, such as

  1. obesity,
  2. systemic hypertension and
  3. dyslipidaemia,
  • defined as the metabolic syndrome.

Insulin resistance has been proposed as the key mediator of all of these features and contributes to the associated high cardiovascular morbidity and mortality. Although the molecular mechanisms behind insulin resistance are not completely understood, a negative cross-talk between

  • AngII (angiotensin II) and the insulin signalling pathway

has been the focus of great interest in the last decade. Indeed,

substantial evidence has shown that

  • anti-hypertensive drugs that block the RAS (renin–angiotensin system) may also act to prevent diabetes.

Despite its long history, new components within the RAS continue to be discovered.

Among them, Ang-(1–7) [angiotensin-(1–7)] has gained special attention as a counter-regulatory hormone

  • opposing many of the AngII-related deleterious effects.

Specifically, we and others have demonstrated that Ang-(1–7) improves the action of insulin and opposes the negative effect that AngII exerts at this level. In the present review, we provide evidence showing that

  • insulin and Ang-(1–7) share a common intracellular signalling pathway.

We also address the molecular mechanisms behind the beneficial effects of Ang-(1–7) on

  • AngII-mediated insulin resistance.

Finally, we discuss potential therapeutic approaches leading to modulation of the

  • ACE2 (angiotensin-converting enzyme 2)/Ang-(1–7)/Mas receptor axis

as a very attractive strategy in the therapy of the metabolic syndrome and diabetes-associated diseases.

Increased Skeletal Muscle Capillarization After Aerobic Exercise Training and Weight Loss Improves Insulin Sensitivity in Adults With IGT

Prior, JB. Blumenthal, LI. Katzel, AP. Goldberg, AS. Ryan. Diabetes Care 2014;37:1469–1475
http://dx.doi.org:/10.2337/dc13-2358

Transcapillary transport of insulin is one determinant of glucose uptake by skeletal muscle; thus,

  • a reduction in capillary density (CD) may worsen insulin sensitivity.

Skeletal muscle CD is lower in older adults with impaired glucose tolerance (IGT) compared with those with normal glucose tolerance and

  • may be modifiable through aerobic exercise training and weight loss (AEX+WL).

Insulin sensitivity (M) and 120-min postprandial glucose (G120) correlated with CD at baseline (r = 0.58 and r = 20.60, respectively, P < 0.05).

AEX+WL increased maximal oxygen consumption (VO2max) 18%(P = 0.02) and reduced weight and fat mass 8% (P < 0.02).

Regression analyses showed that the AEX+WL-induced increase in CD

  • independently predicted the increase in M (r = 0.74, P < 0.01)
  • as well as the decrease in G120 (r = 20.55, P < 0.05).

AEX+WL increases skeletal muscle CD in older adults with IGT. This represents one mechanism by which AEX+WL improves insulin sensitivity in older adults with IGT.

Glycaemic durability with dipeptidyl peptidase-4 inhibitors in type 2 diabetes: a systematic review and meta-analysis of long-term randomised controlled trials.

K Esposito, P Chiodini, MI Maiorino, G Bellastella, A Capuano, D Giugliano. BMJ Open 2014;4:e005442.
http://dx.doi.org:/10.1136/bmjopen-2014-005442

A systematic review and meta-analysis of longterm randomised trials of DPP-4 inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin and alogliptin). on haemoglobin A1c (HbA1c) was conducted. The difference between final and intermediate HbA1c assessment was the primary outcome. All trials were of 76 weeks duration at least. The difference in HbA1c changes between final and intermediate points averaged 0.22% (95% CI 0.15% to 0.29%), with high heterogeneity (I2=91%, p<0.0001). Estimates
of differences were not affected by the analysis of six extension trials (0.24%, 0.02 to 0.46), or five trials in which a DPP-4 inhibitor was added to metformin (0.24%, 0.16 to 0.32).

  • The effect of DPP-4 inhibitors on HbA1c in type 2 diabetes significantly declines during the second year of treatment.

Overcoming Diabetes Mellitus & Borderline Diabetes
By Max Stanley Chartrand, Ph.D. (Behavioral Medicine)

The over-arching biomarker that has more to do with the ability to restore normal metabolic processes is in achieving a cellular pH 7.45 (via the Kreb’s Cycle). To say the least, getting one’s cellular pH to 7.45 and A1C score below 6.0 can be a daunting task!

SIRCLE®: Naturally Achieved Targets

 Cellular pH 7.35-7.45

 Oxygen 99-100% @55-65 bpm

 Resting Blood Pressure: 110-135/ 65-80

mmHg (differs male vs female)

 Fasting blood sugar consistently <70-99

mg/dL or 3.5-5.5 mmol/L

 HgA1C score: .04-5.8

 HDL: 40-60 mg/dL; LDL: 100 -140 mg/dL;

triglycerides: <85 mg/dL

 C-Reactive Protein (CRP) Score <.5

 Galectin-3 Assay <17.8 ng/mL

Antidiabetic Activity of Hydroalcoholic Extracts of Nardostachys jatamansi in Alloxan-induced Diabetic Rats

M.A. Aleem, B.S. Asad, T Mohammed, R.A. Khan, M.F. Ahmed, A. Anjum, M. Ibrahim. Brit J Med & Medical Res 4(28): 4665-4673, 2014. http://www.sciencedomain.org/review-history.php?iid=579&id=12&aid=5024

The antidiabetic study was carried out to estimate the anti hyperglycemic potential of Nardostachys Jatamansi rhizome’s hydroalcoholic extracts in alloxan induced diabetic rats over a period of two weeks. The hydroalcoholic extract HAE1 at a dose (500mg/kg) exhibited significantly greater antihyperglycemic activity than extract HAE2 at a dose (500mg/kg) in diabetic rats. The hydroalcoholic extracts showed improvement in different parameters associated with diabetes, like body weight, lipid
profile and biochemical parameters. Extracts also showed improvement in

  • regeneration of β-cells of pancreas in diabetic rats.

Histopathological studies support the healing of pancreas by hydro alcoholic extracts (HAE1& HAE2) of Nardostachys Jatamansi, as a probable mechanism of their antidiabetic activity.

Antidiabetic and Antihyperlipidemic Effect of Parmelia Perlata. Ach. in Alloxan Induced Diabetic Rats.
Jothi G and Brindha P
Internat J of Pharmacy and Pharmaceut Sciences 2014; 6(suppl 1)

The aqueous extract of the selected plant was administered at dose levels of 200mg and 400mg/kg body weight for 60 days. After the experimental period the blood and tissue samples were collected and subjected to various biochemical and enzymic parameters. There were profound alteration in

  • fasting blood glucose,
  • serum insulin,
  • glycosylated hemoglobin (HbA1C) and
  • liver glycogen levels in alloxanized rats.
  1. Glucose-6-phosphatase,
  2. glucokinase, and
  3. fructose 1-6 bisphosphatase activity
  • were also altered in diabetic rats.

Administration of plant extract significantly (P<0.05)

  • reduced the fasting blood glucose and HbA1C level and increased the level of plasma insulin.

The activities of glucose metabolizing enzymes were also resumed to normal. There was a profound improvement in serum lipid profiles by

  • reducing serum triglyceride, cholesterol, LDL, VLDL, free fatty acids, phospholipids and increasing the HDL level in a dose dependent manner.

The effects of leaf extract were compared with standard drug glibenclamide (600μg/Kg bw). The results indicate that Parmelia perlata. Ach., Linn. could be a good natural source for developing an antidiabetic drug that can effectively maintained the blood glucose levels and lipid profile to near normal values.

Pathophysiological Insights
Diabetic glomerulosclerosis

Reviewers: Nikhil Sangle, M.D.
Revised: 21 February 2014,
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

General

==================================================

  • Diffuse capillary basement membrane thickening, diffuse and nodular glomerulosclerosis
  • Causes glomerular disease, arteriolar sclerosis, pyelonephritis, papillary necrosis; similar between type I and II patients
  • Accounts for 30% of long term dialysis patients in US; causes 20% of deaths in patients with diabetes < age 40
  • Changes may be related to nephronectin, which functions in the assembly of extracellular matrix (Nephrol Dial Transplant 2012;27:1889)

Clinical features

==================================================

  • Proteinuria occurs in 50%, usually 12-22 years after onset of diabetes
  • End stage renal disease occurs in 30% of type I patients
  • Early increased GFR and microalbuminemia (30-300 mg/day) are predictive of future diabetic nephropathy
  • Renal disease reduced by tight diabetic control; may recur with renal allografts; ACE inhibitors may reduce progression

Micro description

==================================================

  • Basement membrane thickening and increased mesangial matrix in ALL patients
  • Diffuse glomerulosclerosis: increase in mesangial matrix associated with PAS+ basement membrane thickening, eventually obliterates mesangial cells
  • Nodular glomerulosclerosis: also called intercapillary glomerulosclerosis or Kimmelstiel-Wilson disease; ovoid, spherical, laminated hyaline masses in peripheral of glomerulus, PAS+, eventually obliterates glomerular tuft; specific for diabetes and membranoproliferative glomerulonephritis, light-chain disease and amyloidosis (Hum Pathol 1993;24:77 (pathogenesis of Kimmelstiel-Wilson nodule))
  • Profound hyalinization of afferent arterioles (insudative lesion-intramural): specific for diabetes in afferent arterioles, but non-specific if in periphery of glomerular loop, Bowman’s capsule or mesangium; insudative material composed of proteins, lipids and mucopolysaccharides
  • Organizing fibroepithelial crescents: associated with aggressive clinical course
  • Diffuse thickening of tubular basement membrane, tubular atrophy and interstitial fibrosis
  • Isolated thickened glomerular basement membrane and proteinuria may be an early predictor of diabetic disease (Mod Pathol 2004;17:1506)

Nodular glomerulosclerosis, Kidney

 Glomeruli:

  1.     Acellular, homogeneous, eosinophilic, globular nodules in the mesangial orintercapillary region of a glomerular tuft with capillary displaced to the periphery.
  2.     Diffuse intercapillary glomerulosclerosis: increasing eosinophilic mesangial matrix materials.
  3.     Capsular drop: eosinophilic small nodules on Bowman’s capsule.
  4.     Fibrin cap: eosinophilic, waxy, fatty structure within the lumen of one or more capillary loops of glomerular tufts.
nodular glomeruloschlerosis

nodular glomeruloschlerosis

http://www.kidneypathology.com/Imagenes/Diabetes/Imagen.Hial.jul.w.jpg

Islet amyloid polypeptide, islet amyloid, and diabetes mellitus.

Westermark P1, Andersson A, Westermark GT.
Physiol Rev. 2011 Jul;91(3):795-826.
http://dx.doi.org:/10.1152/physrev.00042.2009.

Islet amyloid polypeptide (IAPP), or amylin, was named for its tendency to

  • aggregate into insoluble amyloid fibrils, features typical of islets of most individuals with type 2 diabetes.

This pathological characteristic is most probably of

  • great importance for the development of the β-cell failure in this disease,
  • but the molecule also has regulatory properties in normal physiology.

In addition, it possibly contributes to the diabetic condition. This review deals with both these facets of IAPP.

Islet amyloid polypeptide (IAPP, or amylin) is one of the major secretory products of β-cells of the pancreatic islets of Langerhans. It is

  • a regulatory peptide with putative function
  • both locally in the islets, where it inhibits insulin and glucagon secretion, and at distant targets.

It has binding sites in the brain, possibly contributing also to satiety regulation and inhibits gastric emptying. Effects on several other organs have also been described.

IAPP was discovered through its ability to

  • aggregate into pancreatic islet amyloid deposits,

which are seen particularly in association with type 2 diabetes in humans and with diabetes in a few other mammalian species, especially monkeys and cats.

Aggregated IAPP has cytotoxic properties and is believed to be

  • of critical importance for the loss of β-cells in type 2 diabetes

and also in pancreatic islets transplanted into individuals with type 1 diabetes. This review deals both with physiological aspects of IAPP and with the

  • pathophysiological role of aggregated forms of IAPP,
  • including mechanisms whereby human IAPP forms toxic aggregates and amyloid fibrils.

Islet amyloid, initially named “islet hyalinization,” was described in 1901 by two researchers independently and for a long time was considered an enigma. It was found to occur in association with diabetes mellitus, particularly in elderly individuals, but its possible pathogenetic importance was often denied. The similarity of the hyaline substance to amyloid was noted at an early date, and some researchers reported staining reactions typical of amyloid. It had been shown in 1959 that

  • amyloid of several types has a characteristic ultrastructure,
  • and islet deposits were found to share this appearance.

When biochemical analyses of amyloid fibrils from systemic primary and secondary amyloidoses showed that

  • these consisted of distinctive proteins,
  • it was suspected that the islet deposits might also be a polymerized protein.

The chemical composition of islet amyloid did not attract much attention even after the characteristics of other amyloid fibrils had been elucidated. The finding that the amyloid in C cell-derived medullary thyroid carcinoma is of polypeptide hormonal origin was an important indication that amyloid in other endocrine tissues also comes from the local secretory products, and it was believed that

  • insulin, or proinsulin, or split products thereof constitute the islet amyloid fibrils.

Immunological trials to characterize the amyloid yielded equivocal results. Only when concentrated formic acid was used on amyloid,

  • extracted from an amyloid-rich insulinoma, was it possible to purify the major fibril protein
  • and characterize it by NH2-terminal amino acid sequence analysis,

which very unexpectedly revealed a novel peptide,

  • not resembling any part of proinsulin
  • but with partial identity to the neuropeptide calcitonin gene-related peptide (CGRP).

Further characterization of the peptide purified from an insulinoma and from islet amyloid of human and feline origin proved it to be a 37-amino acid (aa) residue peptide. The peptide was initially named “insulinoma amyloid peptide” , later diabetes-associated peptide (DAP), and finally islet amyloid polypeptide (IAPP), or “amylin”.

IAPP is a 37-aa residue long peptide, but by the application of molecular biological methods it was quickly shown that IAPP is expressed initially as

  • part of an 89-aa residue preproprotein containing a 22-aa signal peptide and
  • two short flanking peptides, the latter cleaved off at double basic aa residues similar to proinsulin.

IAPP is expressed by one single-copy gene on the short arm of chromosome 12,

  • in contrast to insulin and the other members of the calcitonin family, including
  • CGRP,
  • adrenomedullin, and
  • calcitonin,

all of which are encoded by genes on the evolutionary related chromosome 11.

The preproIAPP gene contains three exons, of which

  • the last two encode the full prepromolecule.

The signal peptide is cleaved

  • off in the endoplasmic reticulum (ER), and
  • conversion of proIAPP to IAPP takes place in the secretory vesicles.

ProIAPP and proinsulin are both processed by the two endoproteases

  • prohormone convertase 2 (PC2) and
  • prohormone convertase 1/3 (PC1/3) and
  • by carboxypeptidase E (CPE) (Figure 1).
amylin

amylin

A: the amino acid sequence of human pro-islet amyloid polypeptide (proIAPP) with the cleavage site for PC2 at the NH2 terminus and the cleavage site for PC1/3 at the COOH terminus, indicated by arrows. The KR residues (blue) that remain at the COOH terminus after PC1/3 processing are removed by carboxypeptidase E. This event exposes the glycine residue that is used for COOH-terminal amidation.
Below is a cartoon of IAPP in blue with the intramolecular S-S bond between residues 2–7 and the amidated COOH terminus.

B: the amino acid sequence of human proinsulin with the basic residues at the B-chain/C-peptide junction and the A-chain/C-peptide/junction indicated in blue and the processing sites indicated by arrows. PC1/3 does almost exclusively process proinsulin at the B-chain/C-peptide junction while PC2 preferentially processes proinsulin at the A-chain/C-peptide junction. The basic residues (RR) (position 31, 32) that remain at the COOH terminus of the B-chain is removed by the carboxypeptidase CPE. Below is a cartoon of insulin A-chain and B-chain in red with intermolecular SS bonds between cystein residues 7 in the A and B chains, between cystein residues at position 19 in the B-chain and 20 in the A-chain and the intermolecular SS bond between cystein residues at position 6 and 11 of the A-chain.

http://physrev.physiology.org/content/physrev/91/3/795/F1.large.jpg

  1. IAPP and insulin genes contain similar promoter elements,
  2. and the transcription factor PDX1 regulates the effects of glucose on both genes.
  3. Glucose stimulated β-cells respond with a parallel expression pattern of IAPP and insulin in the rat.

However, this parallel secretion of IAPP and insulin is altered in experimental diabetes models in rodents. Perfused rat pancreas secreted relatively

  • more IAPP than insulin when exposed to dexamethasone, whereas
  • high doses of streptozotocin or alloxan reduced insulin secretion more than that of IAPP.

Oleat and palmitate increased the expression of IAPP but not of insulin in MIN6 cells. In mice fed a diet high in fat for 6 mo, plasma IAPP increased 4.5 times more than insulin compared with mice fed standard food containing 4% fat.

In human recipients who had become insulin-independent by intrahepatically transplanted islets, there was disproportionately

  • more IAPP than normal secreted during hyperglycemia.

These examples show that the strictly parallel expression of IAPP and insulin may be disturbed under certain conditions.

The crystalline structure of insulin in granules is well characterized.

  • Hexameric insulin, together with zinc, constitutes the core of the mature granules, while
  • IAPP, together with a large number of additional components, including the C peptide, is found in the halo region.

The highly fibrillogenic human IAPP has to be protected in some way from aggregation, which otherwise would take place spontaneously. The fact that very fibril-prone proteins can be kept in solution at high concentrations is known from studies of arthropod silk. The composition of the β-cell granule is extremely complex, and it has many components in addition to insulin and C peptide, in micromolar concentrations.

It is probable that IAPP is protected from aggregation by interaction with other components. Plausible candidates are

  • proinsulin, insulin, or their processing intermediates.

Insulin has been found to be

  • a strong inhibitor of IAPP fibril formation.

This finding has been verified in a number of subsequent studies, which have also shown the potency of the inhibition. The inhibition seems to depend

  • solely on the B-chain,
  • which binds specifically to a short segment of IAPP.

An insulin-to-IAPP ratio of between 1:5 and 1:100 had a strong inhibitory effect. The molar ratio between IAPP and insulin in the granule as a whole is ∼1–2:50.

Type 2 Diabetes, APOE Gene, and the Risk for Dementia and Related Pathologies. The Honolulu-Asia Aging Study

Rita Peila, Beatriz L. Rodriguez and Lenore J. Launer
Diabetes Apr 2002; 51(4): 1256-1262
http://dx.doi.org:/10.2337/diabetes.51.4.1256

Type 2 diabetes may be a risk factor for dementia, but the associated pathological mechanisms remains unclear. We evaluated the association of diabetes

  • alone or combined with the apolipoprotein E (APOE) gene
  • with incident dementia and neuropathological outcomes

in a population-based cohort of 2,574 Japanese-American men enrolled in the Honolulu-Asia Aging Study, including 216 subjects who underwent autopsy. Type 2 diabetes was ascertained by interview and direct glucose testing. Dementia was assessed in 1991 and 1994 by clinical examination and magnetic resonance imaging and was diagnosed according to international guidelines. Logistic regression was used to assess the RR of developing dementia, and log-linear regression was used to estimate the incident rate ratio (IRR) of neuropathological outcomes.

Diabetes was associated with

  1. total dementia (RR 1.5 [95% CI 1.01–2.2]),
  2. Alzheimer’s disease (AD; 1.8 [1.1–2.9]), and
  3. vascular dementia (VsD; 2.3 [1.1–5.0]).

Individuals with both type 2 diabetes and the APOE ε4 allele

  • had an RR of 5.5 (CI 2.2–13.7) for AD compared with those with neither risk factor.

Participants with type 2 diabetes and the ε4 allele had

  • a higher number of hippocampal neuritic plaques (IRR 3.0 [CI 1.2–7.3]) and
  • neurofibrillary tangles in the cortex (IRR 3.5 [1.6–7.5]) and hippocampus (IRR 2.5 [1.5–3.7]), and
  • they had a higher risk of cerebral amyloid angiopathy (RR 6.6, 1.5–29.6).

Type 2 diabetes is a risk factor for AD and VsD. The association between diabetes and AD is particularly strong among carriers of the APOE ε4 allele. The neuropathological data are consistent with the clinical results.

Role of insulin signaling impairment, adiponectin and dyslipidemia in peripheral and central neuropathy in mice

  1. Anderson, MR. King, L Delbruck, CG. Jolivalt
    Dis. Model. Mech. June 2014; 7(6): 625-633
    http://dx.doi.org:/10.1242/dmm.015750

One of the tissues or organs affected by diabetes is the nervous system,

  • predominantly the peripheral system (peripheral polyneuropathy and/or painful peripheral neuropathy)
  • but also the central system with impaired learning, memory and mental flexibility.

The aim of this study was to test the hypothesis that the pre-diabetic or diabetic condition caused by a high-fat diet (HFD) can damage both the peripheral and central nervous systems. Groups of C57BL6 and Swiss Webster mice were fed a diet containing 60% fat for 8 months and compared to control and streptozotocin (STZ)-induced diabetic groups that were fed a standard diet containing 10% fat. Aspects of peripheral nerve function (conduction velocity, thermal sensitivity) and central nervous system function (learning ability, memory) were measured at assorted times during the study. Both strains of mice on HFD developed impaired glucose tolerance, indicative of insulin resistance, but

  • only the C57BL6 mice showed statistically significant hyperglycemia.

STZ-diabetic C57BL6 mice

  • developed learning deficits in the Barnes maze after 8 weeks of diabetes, whereas
  • neither C57BL6 nor Swiss Webster mice fed a HFD showed signs of defects at that time point.

By 6 months on HFD, Swiss Webster mice developed

  • learning and memory deficits in the Barnes maze test,
  • whereas their peripheral nervous system remained normal.

In contrast, C57BL6 mice fed the HFD developed peripheral nerve dysfunction,

  • as indicated by nerve conduction slowing and thermal hyperalgesia,
  • but showed normal learning and memory functions.

Our data indicate that STZ-induced diabetes or a HFD can damage

  • both peripheral and central nervous systems,
  • but learning deficits develop more rapidly in insulin-deficient than in insulin-resistant conditions
  • and only in Swiss Webster mice.

In addition to insulin impairment, dyslipidemia or adiponectinemia might determine the neuropathy phenotype.

Neuroinflammation and neurologic deficits in diabetes linked to brain accumulation of amylin

S Srodulski, S Sharma, AB Bachstetter, JM Brelsfoard, et al.
Molecular Neurodegeneration  2014; 9(30):
http://dx.doi.org:/10.1186/1750-1326-9-30

Background: We recently found that brain tissue from patients with type-2 diabetes (T2D) and cognitive impairment

  • contains deposits of amylin, an amyloidogenic hormone synthesized and co-secreted with insulin by pancreatic β-cells.

Amylin deposition is promoted by

  • chronic hypersecretion of amylin (hyperamylinemia), which is common in humans with obesity or pre-diabetic insulin resistance.

Human amylin oligomerizes quickly when oversecreted, which is toxic,

  • induces inflammation in pancreatic islets and
  • contributes to the development of T2D.

Here, we tested the hypothesis that accumulation of oligomerized amylin affects brain function.

Methods: In contrast to amylin from humans,

  • rodent amylin is neither amyloidogenic nor cytotoxic.

We exploited this fact by comparing

  • rats overexpressing human amylin in the pancreas (HIP rats) with their littermate rats

which express only wild-type (WT) non-amyloidogenic rodent amylin. Cage activity, rotarod and novel object recognition tests were performed on animals nine months of age or older. Amylin deposition in the brain was documented by immunohistochemistry, and western blot. We also measured neuroinflammation by immunohistochemistry, quantitative real-time PCR and cytokine protein levels.

Results: Compared to WT rats, HIP rats show

i) reduced exploratory drive,
ii) impaired recognition memory and
iii) no ability to improve the performance on the rotarod.

The development of neurological deficits is

  • associated with amylin accumulation in the brain.

The level of oligomerized amylin in supernatant fractions and pellets from brain homogenates

  • is almost double in HIP rats compared with WT littermates (P < 0.05).

Large amylin deposits (>50 μm diameter) were also occasionally seen in HIP rat brains. Accumulation of oligomerized amylin

  • alters the brain structure at the molecular level.

Immunohistochemistry analysis with an ED1 antibody indicates possible activated microglia/macrophages which

  • are clustering in areas positive for amylin infiltration.

Multiple inflammatory markers are expressed in HIP rat brains as opposed to WT rats, confirming that

  • amylin deposition in the brain induces a neuroinflammatory response.

Conclusions:

  1. Hyperamylinemia promotes accumulation of oligomerized amylin in the brain
  2. leading to neurological deficits through an oligomerized amylin-mediated inflammatory response.

Additional studies are needed to determine

  • whether brain amylin accumulation may predispose to diabetic brain injury and cognitive decline.

Keywords: Diabetes, Alzheimer’s Disease, Amylin, Pre-diabetes, Insulin Resistance, Inflammation, Behavior

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