CLEARANCE OF POSTPRANDIAL LIPOPROTEINS IN NORMOLIPEMICS - ROLE OF THEAPOLIPOPROTEIN-E PHENOTYPE

The hepatic clearance of triglyceride-rich Lipoproteins is mediated vi a apolipoprotein (ape) E which occurs in three common isoforms, apoE2, apoE3 and apoE4. To study the importance of the apoE isoforms on the response curves of different triglyceride-rich lipoproteins and the ef fect of chylomicron remnants on the composition of HDL, 37 normolipemi cs were investigated after a standardized fatty meal (8 apoE2/E2, 8 ap oE2/E3, 8 apoE3/E3, 7 apoE3/E4 and 6 apoE4/E4). These individuals were matched for see, body mass index, fasting triglycerides, HDL-choleste rol, and apoA-I. A delayed chylomicron remnant clearance was observed only in apoE2 homozygotes. and this delay was neither correlated with fasting lipids nor with peak lipoprotein concentrations. In apoE2/E3 h eterozygotes, in contrast, the defective isoform E2 appears to be comp ensated for by the normal apoE isoform E3. In non-apo-E2/E2 individual s, the chylomicron remnant response was highly correlated with the mag nitude of chylomicron and VLDL responses, with Easting triglycerides, and with the triglycerides enrichment and cholesterol depletion of HDL . These correlations were not observed in apoE2/E2. From these results we conclude that the chylomicron remnant response curve is an indicat or of the extent of postprandial lipemia in non-apoE2/E2 individuals o nly.