Expression of type III hyperlipoproteinemia in apolipoprotein E2 (Arg158 --> Cys) homozygotes is associated with hyperinsulinemia

Type III hyperlipoproteinemia (HLP) is mainly found in homozygous carriers of apolipoprotein E2 (apoE2, Arg158-->Cys). Only a small percentage (< 5%) of these apoE2 homozygotes develops hyperlipidemia, indicating that additional environmental and genetic factors contribute to the expression of type III HLP. In the present study, first, the prevalence of type III HLP among apoE2 homozygotes was estimated in a Dutch population sample of 8888 participants. Second, 68 normocholesterolemic and 162 hypercholesterolemic apoE2 homozygotes (type III HLP patients) were collected to investigate additional factors influencing type III HLP expression. In the Dutch population sample, apoE2 homozygosity occurred with a frequency of 0.6% (57 of 8888 individuals). Among the 57 E2/2 subjects, 10 type III HLP patients were identified (prevalence 18%). Comparison of normocholesterolemic E2/2 subjects and type III HLP patients showed that the latter had a significantly increased body mass index (25.6 +/- 4.0 versus 26.9 +/- 3.8 kg/m(2), respectively; P=0.03) and prevalence of hyperinsulinemia (26% versus 63%, respectively; P<0.001). Multiple linear regression analysis

A functional polymorphism in the glucocorticoid receptor gene and its relation to cardiovascular disease risk in familial hypercholesterolemia

Context: Individuals with the functional ER22/23EK variant in the glucocorticoid receptor gene are relatively resistant to the downstream consequences of glucocorticoids. Evidence suggests that carriers have a more favorable cardiovascular risk profile, but the relationship between this ER22/23EK variant and cardiovascular disease has not been hitherto assessed. Objective: We, therefore, determined whether carriership of the ER22/23EK improves cardiovascular disease risk in patients with severe hypercholesterolemia. Design, Setting, and Participants: In a multicenter cohort study, 2024 patients with heterozygous familial hypercholesterolemia, aged 18 yr and older, were genotyped for the ER22/23EK polymorphism. Patients were identified at lipid clinics throughout The Netherlands between 1989 and 2002. Main Outcome Measures: The primary outcome measure was cardiovascular disease. Results: Seventy-six (7.8%) of 977 men and 72 (6.9%) of 1047 women were carriers of the ER22/23EK variant. A total of 395 men and 247 women had a cardiovascular event. In contrast to expected results, we observed no significant association of the ER22/23EK variant with cardiovascular disease risk (men: relative risk, 0.75; 95% confidence interval, 0.50-1.14; P = 0.2; women: relative risk, 1.37;95%confidence interval, 0.82-2.28;P = 0.2). However, we found a significant interaction between gender and the polymorphism on cardiovascular disease (P = 0.02). Conclusions: In this large cohort of individuals with very high risk of cardiovascular disease, the association between the functional ER22/23EK polymorphism and cardiovascular risk was not significant overall, although it varied significantly by gender. Copyrigh

Cholesteryl ester transfer protein inhibitor torcetrapib and off-target toxicity: A pooled analysis of the rating atherosclerotic disease change by imaging with a new CETP inhibitor (RADIANCE) trials

Background - Torcetrapib, an inhibitor of cholesteryl ester transfer protein, has been shown to increase the cardiovascular event rate despite conferring a significant high-density lipoprotein cholesterol increase. Using data from the Rating Atherosclerotic Disease Change by Imaging with a New CETP Inhibitor (RADIANCE) trials, which assessed the impact of torcetrapib on carotid intima-media thickness (cIMT), we sought to explore potential mechanisms underlying this adverse outcome. Methods and Results - Data from the RADIANCE 1 and 2 studies, which examined cIMT in 904 subjects with familial hypercholesterolemia and in 752 subjects with mixed dyslipidemia, were pooled. Subjects were randomized to either atorvastatin or torcetrapib combined with atorvastatin. Mean common cIMT progression was increased in subjects receiving torcetrapib plus atorvastatin compared with subjects receiving atorvastatin alone (0.0076±0.0011 versus 0.0025±0.0011 mm/y; P=0.0014). Subjects treated with torcetrapib plus atorvastatin displayed higher postrandomization systolic blood pressure and plasma sodium and bicarbonate levels in conjunction with lower potassium levels. The decrease in potassium levels was associated with the blood pressure increase. Markedly, the use of renin-angiotensin-aldosterone system inhibitors tended to aggravate the blood pressure increase. Subjects receiving torcetrapib plus atorvastatin with the strongest low-density lipoprotein cholesterol reduction showed the smallest cIMT progression, whereas subjects with the highest systolic blood pressure increase showed the largest cIMT progression. High-density lipoprotein cholesterol increase was not associated with cIMT change. Conclusions - These analyses support mineralocorticoid-mediated off-target toxicity in patients receiving torcetrapib as a contributing factor to an adverse outcome. The absence of an inverse relationship between high-density lipoprotein cholesterol change and cIMT progression suggests that torcetrapib-induced high-density lipoprotein cholesterol increase does not mediate atheroprotection. Future studies with cholesteryl ester transfer protein inhibitors without off-target toxicity are needed to settle this issue