Accumulation of apolipoprotein C-I-rich and cholesterol-rich VLDL remnantsduring exaggerated postprandial triglyceridemia in normolipidemic patientswith coronary artery disease

Background-Exaggerated postprandial triglyceridemia is common in normolipid emic patients with coronary artery disease (CAD). Alterations in the compos ition of triglyceride-rich lipoproteins (TRLs) are likely to underlie this metabolic disturbance. However, the composition of very-low-density lipopro teins (VLDLs), which are the most abundant postprandial TRLs, has never bee n defined in CAD patients. Methods and Results-We examined postprandial changes in the number and comp osition of VLDLs in middle-aged, normolipidemic CAD patients and control su bjects. TRLs from 14 patients and 14 control subjects aged 45 to 55 years w ere subfractionated by density gradient ultracentrifugation into Svedberg f lotation rate (Sf) fractions >400, 60 to 400, and 20 to 60. The VLDLs were separated from chylomicron remnants by immunoaffinity chromatography, In CA D patients, the postprandial concentrations of triglycerides and large (Sf 60 to 400) VLDL particles were elevated, In addition, their postprandial la rge VLDLs were enriched in apolipoprotein (apo) C-I and their postprandial small (Sf 20 to 60) VLDL remnants were enriched with apo C-I and cholestero l. Conclusions-Perturbed handling of postprandial triglycerides in normolipide mic CAD patients involves the accumulation of apo C-I-rich large VLDL parti cles and the generation of small, apo C-I- and cholesterol-rich VLDL remnan ts.