Alimentary Lipemia-induced Redistribution of Cholesteryl Ester between Lipoproteins Studies in Normollpidemic, Combined Hyperiipidemic, and Hypercholesterolemic Men

Alimentary llpemla stimulates the transfer of cholesteryl ester between llpoprotelns In vitro and may alter llpoprotein cholesteryl ester distribution In vivo. The effect of a single, large oral fat load on lipoproteln cholesteryl ester redistribution and the activity of cholesteryl ester transfer protein was investigated In six normolipldemlc men (Group A), six combined hyperiipidemic men (Group B), and six hypercholesterolemic men (Group C). Fasting triglyceride-rlch llpoprotein cholesteryl ester was high in Group B, low In Group A, and Intermediate In Group C (A<C<B, p<0.05). After an oral fat load, total plasma cholesteryl ester was unchanged in all groups. In Group A, cholesteryl ester Increased in smaller triglyceride-rich lipoproteins and remained so at 24 hours. Conversely, low density and high density llpoprotein cholesteryl ester decreased and returned to fasting values at 24 hours. In Group B, cholesteryl ester Increased In large trlglycerlde-rlch llpoprotelns. Low density and high density llpoprotein cholesteryl ester (expressed as percentage of plasma cholesteryl ester) decreased. By contrast, In Group C, trlglycerlde-rlch llpoprotein and low density llpoprotein cholesteryl ester remained unaltered, and only high density lipoproteln cholesteryl ester decreased. The activity of cholesteryl ester transfer protein Increased in all groups and returned to fasting values at 24 hours. No differences In response were observed among the three groups. It Is concluded that an oral fat load can Induce a shift in llpoprotein cholesteryl ester distribution from high and low density llpoprotelns to trlgrycerlde-rlch llpoprotelns without affecting total plasma cholesteryl ester. The Induction of trlglycerlde mass and the activity of cholesteryl ester transfer protein appear to be important factors In these changes. The alterations were most pronounced In normollpidemia and combined hyperllpldemla. Minor changes occurred In hypercholesterolemla. (Arteriosclerosis 9:614-622, September/October 1989)