Cholesterol absorption and lipoprotein metabolism in type II diabetes mellitus with and without coronary artery disease

Hypercholesterolemia is an important atherogenic risk factor in type II diabetes, and although coronary artery disease (CAD) is frequent in these patients, it is not known whether cholesterol and lipoprotein metabolism differ in patients with (CAD+) and without CAD (CAD-). Our aim was to study cholesterol metabolism and lipoprotein kinetics in mildly hypercholesterolemic type II diabetic men with and without CAD under similar dietary conditions. Despite similar serum and lipoprotein cholesterol levels, and kinetics of total and dense LDL apo B, light and dense LDL particles were cholesterol-enriched only in CAD+ subjects. Apolipoprotein A-II level was lower in CAD+ than in CAD- subjects (27.1 +/- 0.7 versus 30.9 +/- 0.7 mg/dl, P < 0.05),:HDL cholesterol and apolipoprotein A-I kinetics were similar in the two groups. Cholesterol absorption was significantly higher in the CAD+ versus CAD- subjects (27 +/- 2 versus 20 +/- 3%, P < 0.05). In multiple logistic stepwise regression analysis with CAD as the dependent variable, cholesterol absorption efficiency and serum plant sterol/cholesterol proportions were the only variables significantly associated with CAD. In conclusion, in mildly hypercholesterolemic type II diabetic patients, the only metabolic parameter differentiating CAD patients from non-CAD ones was significantly higher cholesterol absorption efficiency in the coronary patients, which could contribute to the finding of the atherogenic cholesterol-rich dense LDL subfraction in these patients. Thus, a treatment causing cholesterol malabsorption by sitostanol alone or in combination with statin could be beneficial in these patients.