Vitamin E inhibits CD36 scavenger receptor expression in hypercholesterolemic rabbits

A numerous studies suggest that Vitamin E has a preventive role in atherosclerosis, although the mechanism of action still remains unclear. CD36, a member of the scavenger receptor family is centrally involved in the uptake of oxidized low density proteins (oxLDLs) from bloodstream. During the atherosclerotic process, the lipid cargo of oxLDL accumulates in macrophages and smooth muscle cells, inducing their pathological conversion to foam cells. In the present study, we investigate the role of Vitamin E on CD36 expression in an in vivo model. Atherosclerosis was induced by a 2% cholesterol containing Vitamin E poor diet. Three groups of six rabbits each were studied. The first group (control) was fed on Vitamin E poor diet. The second group was fed with Vitamin E poor diet containing 2% cholesterol and the rabbits in the third group were fed with Vitamin E poor diet containing 2% cholesterol and received injections of 50 mg/kg of Vitamin E i.m. After 4 weeks, aortas were removed and analysed by light microscopy for atherosclerotic lesions. Aortic samples were analysed for CD36 mRNA expression. The aortas of cholesterol-fed rabbits showed typical atherosclerotic lesions, detected by macroscopic and microscopic examination, and exhibited an increase in CD36 mRNA expression. Vitamin E fully prevented cholesterol induced atherosclerotic lesions and the induction of CD36 mRNA expression. The effects observed at the level of CD36 scavenger receptor expression in vivo suggest an involvement of reduced foam cell formation in the protective effect of Vitamin E against atherosclerosis.

Fasting plasma glucose predicts survival and angiographic progression in high-risk postmenopausal women with coronary artery disease

BACKGROUND: We studied the association of baseline fasting plasma glucose (FPG) levels with survival and coronary artery disease (CAD) progression among postmenopausal women without unstable angina. METHODS: Women were recruited from seven centers in the Women's Angiographic Vitamin and Estrogen Trial (WAVE) (n = 423). Event follow-up was available for 400 women (65.1 +/- 8.5 years, 66% white, 92% hypertensive, 19% smokers, 67% hypercholesterolemic). Thirty-eight percent of the women had diabetes or FPG > 125 mg/dL, and 21% had a fasting glucose 100-125 mg/dL. Follow-up angiography was performed in 304 women. Cox regression was used to model survival from a composite outcome of death or myocardial infarction (D/MI, 26 events; median follow-up 2.4 years). Angiographic progression was analyzed quantitatively using linear regression accounting for baseline minimum lumen diameter (MLD), follow-up time, and intrasubject correlations using generalized estimating equations. Regression analyses were adjusted for follow-up time, baseline age, treatment assignment, and Framingham risk (excluding diabetes). RESULTS: Women with impaired fasting glucose/diabetes mellitus (IFG/DM) had a relative risk (RR) of D/MI of 4.2 ( p = 0.009). In all women, each 10 mg/dL increase in FPG was associated with an 11% increase ( p < 0.001) in the hazard of D/MI. Each 10 mg/dL increase in FPG was associated with a 6.8 mum decrease in MLD over the follow-up period ( p = 0.005). CONCLUSIONS: Higher FPG is associated with increased risk of D/MI and greater narrowing of the coronary lumen in women with CAD. Aggressive monitoring of glucose levels may be beneficial for secondary CAD prevention.