Effect of lipoprotein concentration and lecithin: cholesterol acyltransferase activity on cholesterol esterification in human plasma after plasma exchange

Abstract

The rate of cholesterol esterification in plasma, plasma lecithin cholesterol acyltransferase (LCAT) activity and plasma lipoprotein levels were measured in 5 [human] subjects who underwent therapeutic plasma exchange to reduce their plasma cholesterol concentration. In the week following the exchange the cholesterol esterification rate and the plasma triglyceride concentration returned rapidly in parallel to pre-exchange levels; high density lipoprotein (HDL) cholesterol and LCAT activity returned to normal more slowly but also in parallel. The rate-limiting factor for cholesterol esterification in plasma is unlikely to be solely the enzyme levels, but is probably a combination of factors, including the enzyme level and substrate abailability or product removal. Plama very low density lipoprotein (VLDL) may provide substrates for the reaction or provide a means of removing one of the products from the site of reaction.