Increased cholesterol concentration in intermediate density lipoprotein fraction of normolipidemic non-insulin-dependent diabetics

There is increasing agreement about the atherogenicity of intermediate density lipoprotein (IDL). In order to determine whether normocholesterolemic diabetics are at a higher risk of atherosclerosis, cholesterol concentrations in three subclasses of triglyceride-rich lipoprotein fraction ( S f 12–400) were examined. Their plasma triglyceride and cholesterol levels were limited to below 150 and 250 mg/dl, respectively. They were divided into 3 groups according to their treatment: insulin injection (group I), sulphonylurea (group S) and diet alone (group D). Age-matched healthy normolipidemic non-obese subjects served as controls (group C). Triglyceride-rich lipoproteins were separated by ultracentrifugation: very low density lipoprotein (VLDL), S f 60–400; intermediate density lipoprotein, (IDL 1), S f 20–60; IDL 2; S f 12–20. Cholesterol concentrations in total plasma, VLDL, IDL 2 and high density lipoprotein (HDL) were all identical in every group. A significant increase in cholesterol concentration was found in IDL 1 of groups S and D. Low density lipoprotein-cholesterol of group I was also increased. These findings indicate an increased risk factor in normolipidemic diabetics.