Postprandial metabolism of apolipoprotein B-48-and B-100-containing particles in type 2 diabetes mellitus: relations to angiographically verified severity of coronary artery disease

The aim of the present cross-sectional angiographic study was to examine if there is a relationship between the severity of CAD and postprandial lipem ia in patients with type 2 diabetes mellitus. Special emphasis was directed to determining the contribution of apolipoprotein B-48 (apoB-48)-containin g and B-100 (apoB-100)-containing triglyceride-rich particles to the magnit ude of postprandial lipemia and degree of CAD. The role of apolipoprotein E (apoE) phenotype as a modulator of postprandial lipemia was also evaluated . The severity of CAD was determined by a quantitative coronary angiography and the subjects were classified into two groups based on the presence (se vere CAD) or absence (mild CAD) of at least 50% stenosis in a major coronar y vessel. The study population consisted of 43 subjects (31 men and 12 wome n) with fair glycemic control and comparable fasting lipids and body mass i ndex. Postprandial responses of TG, apoB-48 and apoB-100 in lipoprotein sub fractions (chylomicrons, VLDL1, VLDL2 and IDL) were determined after a fat load. Type 2 diabetic patients exhibited the classical dyslipidemia of the insulin resistance syndrome and delayed clearance of both hepatic and intes tinal particles. Fasting or postprandial lipid or lipoprotein measurements, including apoB-48 and apoB-100 concentrations, did not differ between the groups. The presence or absence of apoE-4 allele did not significantly infl uence postprandial lipemia. The severity of the most significant coronary s tenosis in angiography correlated with plasma and with chylomicron area und er curve (AUC) for TG (n = 27) and chylomicron AUC for apoB-48 (n = 20). Th e strongest correlate of maximal stenosis was area under incremental curve (AUIC) for apoB-100 in IDL fraction (r=0.548, P=0.012, n=20). In conclusion , postprandial apoB-48 and apoB-100 metabolism in triglyceride rich lipopro teins is distorted in type 2 diabetic patients, even in those with only mil d CAD. The data suggest that postprandial change in small remnant particle numbers may contribute to the severity of CAD in type 2 diabetes. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.