Postprandial changes in high-density lipoprotein composition and subfraction distribution are not altered in patients...

A detailed analysis of postprandial changes in the size, density, composition, and relative proportion of the major high-density lipoprotein (HDL) subfractions, HDL2 and HDL3, was performed in seven normolipidemic patients with insulin-dependent diabetes mellitus (IDDM) in moderate glycemic control and seven age-, sex-, and weight-matched healthy nondiabetic controls. IDDM subjects received an overnight insulin infusion to maintain euglycemia, with an incremental increase in the insulin infusion rate at the time of the test meal (containing 60 g fat/m2). Samples for detailed analysis of HDL by gradient density ultracentrifugation and nondenaturing gradient gel electrophoresis (GGE) were collected at 0, 4, Br, and 12 hours after the test meal. The composition of HDL, HDL2, and HDL3 was significantly altered in the postprandial state in IDDM subjects and controls with an increase in triglyceride content at 4 to 8 hours and a reciprocal decrease in cholesteryl ester, reflecting exchange of lipid constituents of HDL with triglyceride (TG)-rich lipoproteins. In addition, the phospholipid content of the particles increased at 8 hours after the meal. Peak density of HDL2 and HDL3 decreased slightly at 4 to 8 hours, reaching significance only in controls at 8 hours (P < .05), whereas the mean radius size of these subfractions did not change significantly. In controls and IDDM subjects, the ratio of HDL3 to HDL2 at 8 to 12 hours increased significantly (P < .005). Significant differences in the composition, size, density, or subfraction distribution of HDL between subjects with IDDM and controls were not observed following ingestion of the lipid-rich meal. We conclude from these data that in patients with IDDM in moderate glycemic control, there do not appear to be any significant gross abnormalities in postprandial HDL metabolism with respect to the size, density, or compositional changes of HDL particles.