Jean Bergeron

Hypertriglyceridemic Waist A Marker of the Atherogenic Metabolic Triad (Hyperinsulinemia; Hyperapolipoprotein B; Small, Dense LDL) in Men?

BACKGROUND The present study tested the hypothesis that simple variables, such as waist circumference and fasting plasma triglyceride (TG) concentrations, could be used as screening tools for the identification of men characterized by a metabolic triad of nontraditional risk factors (elevated insulin and apolipoprotein [apo] B and small, dense LDL particles). METHODS AND RESULTS Results of the metabolic study (study 1) conducted on 185 healthy men indicate that a large proportion (>80%) of men with waist circumference values >/=90 cm and with elevated TG levels (>/=2.0 mmol/L) were characterized by the atherogenic metabolic triad. Validation of the model in an angiographic study (study 2) on a sample of 287 men with and without coronary artery disease (CAD) revealed that only men with both elevated waist and TG levels were at increased risk of CAD (odds ratio of 3.6, P<0.03) compared with men with low waist and TG levels. CONCLUSIONS It is suggested that the simultaneous measurement and interpretation of waist circumference and fasting TG could be used as inexpensive screening tools to identify men characterized by the atherogenic metabolic triad (hyperinsulinemia, elevated apo B, small, dense LDL) and at high risk for CAD.

Elevated C-Reactive Protein Another Component of the Atherothrombotic Profile of Abdominal Obesity

Recent studies have suggested that elevated plasma C-reactive protein (CRP) levels are associated with the features of insulin resistance syndrome. In the present study, we have examined the contribution of body composition measured by hydrostatic weighing and of abdominal adipose tissue (AT) accumulation assessed by computed tomography to the variation in plasma CRP levels associated with atherogenic dyslipidemia of the insulin resistance syndrome in a sample of 159 men, aged 22 to 63 years, covering a wide range of adiposity (body mass index values from 21 to 41 kg/m2). Plasma CRP levels showed positive and significant correlations with body fat mass (r =0.41, P <0.0001), waist girth (r =0.37, P <0.0001), and visceral AT accumulation measured by computed tomography at L4 to L5 (r =0.28, P < 0.0003). Although CRP levels were associated with plasma insulin levels measured in the fasting state and after a 75-g oral glucose load, no significant correlations were found with plasma lipoprotein levels. Finally, comparison of body fatness, of abdominal fat accumulation, and of the features of the insulin resistance syndrome across quintiles of CRP revealed major differences in body fatness and in indices of abdominal AT accumulation between the lowest and the highest CRP quintiles, whereas no significant differences were found for variables of the plasma lipoprotein-lipid profile. These results suggest that obesity and abdominal AT accumulation are the critical correlates of elevated plasma CRP levels found in men with atherogenic dyslipidemia of the insulin resistance syndrome.

Effect of a monoclonal antibody to PCSK9, REGN727/SAR236553, to reduce low-density lipoprotein cholesterol in patients with heterozygous familial hypercholesterolaemia on stable statin dose with or without ezetimibe therapy: a phase 2 randomised controlled trial

BACKGROUND Inhibition of proprotein convertase subtilisin/kexin type 9 serine protease (PCSK9) resulted in large reductions of low-density lipoprotein cholesterol (LDL-C) in phase 1 trials. We assessed the efficacy and safety of various doses and dosing intervals of REGN727, a monoclonal antibody to PCSK9, added to statins, to further lower LDL-C in patients with heterozygous familial hypercholesterolaemia. METHODS This multicentre, randomised, placebo-controlled phase 2 trial was done at 16 lipid clinics in the USA and Canada. Between Jan 18, 2011, and Nov 7, 2011, we enrolled adults with heterozygous familial hypercholesterolaemia and LDL-C concentrations of 2·6 mmol/L or higher on stable diet and statin dose, with or without ezetimibe. Patients were randomly assigned to receive REGN727 150 mg, 200 mg, or 300 mg every 4 weeks, or 150 mg every 2 weeks, or placebo every 2 weeks (ratio 1:1:1:1:1). Randomisation was stratified by concomitant use of ezetimibe at baseline. Investigators, study staff, and patients were masked to treatment group. Blinding was maintained by administration of placebo alternating with REGN727 for the groups of 4 week dosing. The primary endpoint was mean percent reduction in LDL-C from baseline at week 12 and was analysed in the modified intention-to-treat population with an analysis of covariance (ANCOVA) model with treatment group. This trial is registered in ClinicalTrials.gov, number NCT 01266876. FINDINGS 77 patients were randomly assigned to study groups (15-16 patients per group) and all were analysed. Least-squares (LS) mean LDL-C reduction from baseline to week 12 was 28·9% (SE 5·08) for 150 mg every 4 weeks (p=0·0113), 31·54% (4·91) for 200 mg every 4 weeks (p=0·0035), 42·53% (5·09) for 300 mg every 4 weeks (p<0·0001), and 67·90% (4·85) for 150 mg every 2 weeks (p<0·0001), compared with 10·65% (5·04) with placebo. One serious adverse event was reported with placebo and none with REGN727. No increases of more than three times the upper limit of normal were reported for hepatic transaminases or creatinine kinase. The most common adverse event was injection-site reaction with one patient in the group of 300 mg REGN727 terminating treatment. INTERPRETATION REGN727 was well tolerated and achieved substantial further LDL-C reduction in patients with heterozygous familial hypercholesterolaemia and elevated LDL-C treated with high-dose statins, with or without ezetimibe. REGN727 has the potential to provide optimum control of LDL-C in patients with this disorder. FUNDING Sanofi US and Regeneron Pharmaceuticals Incorporated.

Race, Visceral Adipose Tissue, Plasma Lipids, and Lipoprotein Lipase Activity in Men and Women: The Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study

Abdominal obesity is associated with numerous metabolic alterations, such as hypertriglyceridemia and low levels of high density lipoprotein (HDL) cholesterol. However, compared with abdominally obese white individuals, abdominally obese black individuals have been characterized by higher plasma HDL cholesterol levels, suggesting that the impact of abdominal fat accumulation on the lipoprotein-lipid profile may differ among ethnic groups. Therefore, we have compared the associations between body fatness, visceral adipose tissue (AT) accumulation, and metabolic risk variables in a sample of 247 white men and 240 white women versus a sample of 93 black men and 143 black women. Although no difference in mean total body fatness was found between the 2 race groups, white men had higher levels of visceral AT than did black men (P<0.001). Despite the fact that black women had a greater body fat content than did white women, black women had levels of visceral AT that were similar to those of white women, suggesting a lower susceptibility to visceral obesity in black women. This lower accumulation of visceral AT in blacks was accompanied by significantly reduced apolipoprotein B concentrations and ratios of total cholesterol to HDL cholesterol as well as higher plasma HDL cholesterol levels (P<0.05) compared with those values in whites. Irrespective of sex, higher postheparin plasma hepatic lipase (HL) and lower lipoprotein lipase (LPL) activities were found in whites, resulting in an HL/LPL ratio that was twice as high in whites as in blacks (P<0.005). Although differences in lipoprotein-lipid levels were noted between whites and blacks, results from multiple regression analyses revealed that after control for morphometric and metabolic variables of the study (body fat mass, visceral AT, LPL, HL, and age), ethnicity had, per se, only a minor contribution to the variance in plasma lipoprotein levels. Thus, our results suggest that the higher plasma HDL cholesterol levels and the generally more cardioprotective plasma lipoprotein profile found in abdominally obese black versus white individuals are explained, at least to a certain extent, by a lower visceral AT deposition and a higher plasma LPL activity in black individuals.

Stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood: the Québec Family Study

The stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood was examined. The sample included 76 males and 71 females measured between the ages of 8 and 18 years and again as young adults (12 year follow-up). Indicators included the sum of three trunk skinfolds (SF3), mean blood pressure (MBP), and fasting blood glucose (GLY), high-density lipoprotein cholesterol (HDL-C), ratio of total cholesterol to HDL-C (CHOL/HDL), and triglycerides (TG). The indicators were subjected to principal components analysis to obtain a composite risk factor index (RFI). Partial interage correlations, controlling for initial age and length of follow-up, were 0.70 and 0.50 for SF3, 0.40 and 0.54 for MBP, 0.58 and 0.56 for HDL-C, 0.51 and 0.57 for CHOL/HDL, 0.37 and 0.20 (NS) for TG, 0.30 and 0.14 (NS) for GLY, and 0.51 and 0.46 for the RFI, in males and females, respectively. The results indicate that indicators of the metabolic syndrome are moderately stable from childhood and adolescence into young adulthood.

Impact of Waist Circumference on the Relationship Between Blood Pressure and Insulin: The Quebec Health Survey

Hyperinsulinemia has been suggested to be involved in the etiology of obesity-associated hypertension. The objective of the present study was to quantify, in a population-based study, the respective contributions of excess adiposity (body mass index [BMI]), waist circumference (WC), fasting insulin levels, and insulin sensitivity to the variation of resting blood pressure. The Quebec Health Survey was used to obtain fasting plasma insulin and glucose levels and resting blood pressure as well as anthropometric measurements in a representative sample of 907 men and 937 women. When the sample was divided into tertiles of BMI and further stratified on the basis of the 50th percentile of WC (88 cm in men), nonobese men in the first BMI tertile (<23.2 kg/m2) but with abdominal obesity were characterized by an increased systolic blood pressure (SBP) compared with nonobese men with low WC (130±18 versus 120±11 mm Hg; mean±SD; P=0.075). The SBP was comparable to SBP values measured among men in the top BMI tertile (129±14 mm Hg for BMI ≥26.6 kg/m2). When subjects were classified into tertiles of fasting insulin and WC, no association between insulin levels and blood pressure was noted, once the variation in WC was considered. Insulin sensitivity (estimated with homeostasis model assessment [HOMA]) did not explain variation in blood pressure in men, whereas the contribution of HOMA in women was of marginal clinical significance (R2 of <1.3%; P<0.0001). These results suggest that the documented association between obesity, fasting insulin, insulin sensitivity, and blood pressure is largely explained by concomitant variation in WC.

Efficacy and safety of alirocumab vs ezetimibe in statin-intolerant patients, with a statin rechallenge arm: The ODYSSEY ALTERNATIVE randomized trial

BACKGROUND Statin intolerance limits many patients from achieving optimal low-density lipoprotein cholesterol (LDL-C) concentrations. Current options for such patients include using a lower but tolerated dose of a statin and adding or switching to ezetimibe or other non-statin therapies. METHODS ODYSSEY ALTERNATIVE (NCT01709513) compared alirocumab with ezetimibe in patients at moderate to high cardiovascular risk with statin intolerance (unable to tolerate ≥2 statins, including one at the lowest approved starting dose) due to muscle symptoms. A placebo run-in and statin rechallenge arm were included in an attempt to confirm intolerance. Patients (n = 361) received single-blind subcutaneous (SC) and oral placebo for 4 weeks during placebo run-in. Patients reporting muscle-related symptoms during the run-in were to be withdrawn. Continuing patients were randomized (2:2:1) to double-blind alirocumab 75 mg SC every 2 weeks (Q2W; plus oral placebo), ezetimibe 10 mg/d (plus SC placebo Q2W), or atorvastatin 20 mg/d (rechallenge; plus SC placebo Q2W) for 24 weeks. Alirocumab dose was increased to 150 mg Q2W at week 12 depending on week 8 LDL-C values. Primary end point was percent change in LDL-C from baseline to week 24 (intent-to-treat) for alirocumab vs ezetimibe. RESULTS Baseline mean (standard deviation) LDL-C was 191.3 (69.3) mg/dL (5.0 [1.8] mmol/L). Alirocumab reduced mean (standard error) LDL-C by 45.0% (2.2%) vs 14.6% (2.2%) with ezetimibe (mean difference 30.4% [3.1%], P < .0001). Skeletal muscle-related events were less frequent with alirocumab vs atorvastatin (hazard ratio 0.61, 95% confidence interval 0.38-0.99, P = .042). CONCLUSIONS Alirocumab produced greater LDL-C reductions than ezetimibe in statin-intolerant patients, with fewer skeletal-muscle adverse events vs atorvastatin.

Blood lipid response to 20 weeks of supervised exercise in a large biracial population: The HERITAGE family study

We studied the effects of 20 weeks of supervised cycle-ergometer exercise on plasma lipids in 675 healthy, sedentary, normolipidemic white and black men and women aged 17 to 65 years, participating in the HERITAGE Family Study. Fasting plasma lipids were assessed twice at baseline and 24 and 72 hours after the last exercise session and adjusted for plasma volume changes. No significant differences from the mean baseline levels were observed for total, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) cholesterol and apolipoprotein B (Apo B). A significant reduction (P < .01) from baseline levels in plasma total and VLDL triglycerides was observed only in the 24-hour posttraining specimens, reflecting a response to the last bout of exercise. High-density lipoprotein (HDL) cholesterol increased 3.6% for the combined group, primarily due to an increase in HDL2, with an associated increase in Apo A-1 (P < .001). No significant differences were noted in the HDL response by sex, race, or age. An inverse correlation (r = -.241) was observed between the increase in HDL cholesterol and change in body fat only in men, and the increase in HDL cholesterol was unrelated to the change in maximal oxygen uptake (VO2max).

Visceral Obesity and Plasma Glucose-Insulin Homeostasis: Contributions of Interleukin-6 and Tumor Necrosis Factor-α in Men

OBJECTIVE This study examined the relationships of two inflammatory cytokines, IL-6 and TNF-alpha, to visceral adiposity and indices of plasma glucose-insulin homeostasis. RESEARCH DESIGN AND METHODS Plasma levels of IL-6 and TNF-alpha were measured in 189 untreated asymptomatic men (aged 43.7 +/- 7.8 yr; body mass index 29.0 +/- 4.3 kg/m(2); waist girth 98.6 +/- 10.3 cm). RESULTS Significant and positive associations were found between both cytokines with adiposity and adipose tissue distribution indices (0.15 < or = r < 0.32; P < 0.05) as well as plasma glucose-insulin homeostasis variables (0.22 < or = r < 0.28; P <0.05). Comparison of two subgroups, each composed of 32 overweight men (> or =25 kg/m(2)) with similar body mass index values (28.7 kg/m(2) in both groups) but with markedly different levels of visceral adipose tissue (< vs. > or = 130 cm(2)), revealed significant differences only for IL-6 levels (1.42 +/- 1.15 vs. 0.86 +/- 0.52 pg/ml; P < 0.02 for men with high vs. low visceral adipose tissue, respectively). Finally, when subjects were stratified on the basis of their respective concentrations of IL-6 and TNF-alpha (using the 50th percentile of their overall distribution), an ANOVA revealed an independent contribution of IL-6 to the variation of fasting insulin (P < 0.01) and each of these two cytokines to the variation of insulin levels measured after a 75-g oral glucose challenge (P <0.01 for IL-6 and P < 0.05 for TNF-alpha). CONCLUSIONS Because IL-6 appeared to be clearly associated with visceral adiposity, TNF-alpha rather showed associations with indices of total body fatness. Thus, TNF-alpha may contribute to the insulin resistance of overall obesity, whereas IL-6 may be one of the mediators of the hyperinsulinemic state specifically related to excess visceral adiposity.

Hypertriglyceridemic waist: A useful screening phenotype in preventive cardiology?

The worldwide increase in the prevalence and incidence of type 2 diabetes represents a tremendous challenge for the Canadian health care system, especially if we consider that this phenomenon may largely be explained by the epidemic of obesity. However, despite the well-recognized increased morbidity and mortality associated with an elevated body weight, there is now more and more evidence highlighting the importance of intra-abdominal adipose tissue (visceral adipose tissue) as the fat depot conveying the greatest risk of metabolic complications. In this regard, body fat distribution, especially visceral adipose tissue accumulation, has been found to be a key correlate of a cluster of diabetogenic, atherogenic, prothrombotic and inflammatory metabolic abnormalities now often referred to as the metabolic syndrome. This dysmetabolic profile is predictive of a substantially increased risk of coronary artery disease (CAD) even in the absence of hyperglycemia, elevated low-density lipoprotein cholesterol or hypertension. For instance, some features of the metabolic syndrome (hyperinsulinemia, elevated apolipoprotein B and small low-density lipoprotein particles--the so-called atherogenic metabolic triad) have been associated with a more than 20-fold increase in the risk of ischemic heart disease in middle-aged men enrolled in the Quebec Cardiovascular Study. This cluster of metabolic complications has also been found to be predictive of a substantially increased risk of CAD beyond the presence of traditional risk factors. These results emphasize the importance of taking into account in daily clinical practice the presence of metabolic complications associated with abdominal obesity together with traditional risk factors to properly evaluate the cardiovascular risk profile of patients. From a risk assessment standpoint, on the basis of additional work conducted by several groups, there is now evidence that the simultaneous presence of an elevated waist circumference and fasting triglyceride levels (a condition that has been described as hypertriglyceridemic waist) may represent a relevant first-step approach to identify a subgroup of individuals at higher risk of being carriers of the features of the metabolic syndrome. Moreover, a moderate weight loss in initially abdominally obese patients is associated with a selective mobilization of visceral adipose tissue, leading to improvements in the metabolic risk profile predictive of a reduced risk of CAD and type 2 diabetes. In conclusion, hypertriglyceridemic waist as a marker of visceral obesity and related metabolic abnormalities is a useful and practical clinical phenotype to screen persons at risk for CAD and type 2 diabetes.