Apolipoprotein EPolymorphism Influences Postprandial Retinyl Palmitate butNotTriglyceride Concentrations

Summary Toquantify theeffect oftheapolipoprotein (apo) Epolymorphism on themagnitude ofpostprandial lipemia, we havedefined its role indetermining the responsetoasingle high-fat mealinalarge sample of(N= 474) individuals taking partinthebiethnic Atherosclerosis RiskinCommunities Study. Theprofile ofpostprandial responseinplasma was monitored over8hbytriglyceride, triglyceride-rich lipoprotein (TGRL)-triglyceride, apo B-48/apo B-100ratio, andretinyl palmitate concentrations, andthe apo Epolymorphism was determined byDNA amplification anddigestion. Thefrequency ofthe apoEalleles andtheir effects on fasting lipid levels inthis sample weresimilar tothose reported elsewhere. Postprandial plasma retinyl palmitate responsetoa high-fat mealwithvitamin A was significantly different among apo Egenotypes, withdelayed clearance in individuals with an £2allele, compared with£3/3and£3/4individuals. Inthesample of397Caucasians, averageretinyl palmitate responsewas 1,489ttg/dl in£2/3individuals, compared with1,037 jig/dl in£3/3 individuals and1,108Ftg/dl in£3/4individuals. Theapo Epolymorphism accounted for7.1%ofthe interindividual variation inpostprandial retinyl palmitate response,acontribution proportionally greaterthan its well-known effect on fasting LDL-cholesterol. However, despite this effect on postprandial retinyl palmitate, theprofile ofpostprandial triglyceride responsewas notsignificantly different among apo Egenotypes. The profile ofpostprandial responsewas consistent between thesample ofCaucasians andasmaller sample ofblack subjects. While these data indicate that theremoval ofremnantparticles fromcirculation isdelayed insubjects withthe£2/3genotype,there isno reported evidence that the£2allele predisposes tocoronaryarterydisease (CAD). Theresults ofthis study provide notonly areliable estimate ofthemagnitude oftheeffect ofthe apo Epolymorphism on various measurementscommonly used tocharacterize postprandial lipemia, butalso provide mechanistic insight into theeffects ofthe apo Egenepolymorphism on postprandial lipemia andCAD.