Differences in Lipoprotein Subfraction Composition and Distribution Between Type I Diabetic Men and Control Subjects

Subfractions of very-low-density and low-density lipoproteins were examined in 10 male normolipidemic type I (insulin-dependent) diabetic patients before and after improvement of metabolic control and were compared with subfractions from male control subjects matched to the diabetic patients at entry for age, body mass index, plasma cholesterol, and plasma triglycerides. Two consistent differences in subfraction composition were noted between the diabetic patients at entry and the control subjects. First, subfractions from diabetic patients tended to be cholesterol-ester poor and triglyceride rich; this was particularly marked for the low-density lipoprotein subfractions. Second, the subfractions from pretreatment diabetic patients contained higher proportions of non-apolipoprotein B apolipoproteins. This compositional anomaly, but not the lipid modifications, responded to but was not completely normalized by improved glycemic control, which was also accompanied by reductions in the plasma concentrations of all subfractions. Treatment modified subfraction distribution so that the lipoprotein profile of posttreatment diabetic patients more closely resembled the profile observed in the control subjects. These changes were achieved without significant modification of daily insulin dose. In the context of blood lipid risk factors, the results argue for the need to maintain optimal insulinization even in apparently normolipidemic diabetic patients to avoid modifications of the lipoprotein pattern toward a potentially more atherogenic profile.