Lecithin: cholesterol acyl transfer rate and high density lipoproteins in plasma during dietary and cholestyramine treatment of type Ila hyperlipoproteinaemia

Abstract

Abstract. Changes in the lecithin:cholesterol acyl transfer rate and the concentrations of lipids and high density lipoprotein lipids in plasma were studied during dietary and cholestyramine treatment of type IIa subjects. Samples were obtained from twenty subjects before and 2 months after the start of a cholesterol lowering diet. Sixteen subjects were studied 1 month after the addition of cholestyramine treatment to the dietary regimen.During 2 months of dietary modification the mean concentrations of cholesterol, phospholipids and low density lipoprotein cholesterol were reduced by 10%. In the high density lipoprotein fraction there was a 10% mean increase of the cholesterol but no change of the mean phospholipid concentration. There were no changes of the mean triglyceride concentration or the mean fractional or molar lecithin:cholesterol acyl transfer rates in plasma.One month after the addition of cholestyramine to the diet there were further reductions in the mean plasma concentrations of cholesterol by 22.5%, phospholipids by 12% and low density lipoprotein cholesterol by 32%. The mean triglyceride concentration and the mean concentration and composition of the high density lipoprotein fraction were unchanged. The mean fractional Iecithin :cholesterol acyl transfer rate was increased by 30%. The type IIa subjects with high molar lecithin: cholesterol acyl transfer rates during the diet showed increments of molar lecithin:cholesterol acyl transfer rates during cholestyramine therapy.Interpretations of these findings in relation to lipoprotein metabolism are discussed.