Postabsorptive retinyl palmitate removal is retarded in lecithin-cholesterol acyltransferase deficiency

Postabsorption fat clearance of intestinal lipoproteins indicated by retinyl palmitate was studied in two siblings with the classical lecithin-cholesterol acyltransferase (LCAT) deficiency and in a control group of 21 healthy subjects with similar apoprotein E 3/3 phenotype. Relatively high pre- and postabsorptive cholesterol esterification percentage of chylomicrons suggested that acyl coenzyme A:cholesterol acyltransferase activity was not inhibited. Postabsorptive levels of plasma lipids increased and decreased roughly similarly in the cases and controls with the postabsorptive peak values at about 4 h. Plasma total and chylomicron levels of retinyl palmitate were not affected by LCAT deficiency, while the removal of the vitamin from very low and intermediate density lipoproteins was clearly reduced so that the peak concentrations, values under the response curves and the time of the peak concentrations were markedly higher than in the controls. The long-lasting circulation of chylomicron remnants of density < 1.006-1.019 g ml-1 may have some clinical significance because postabsorptive lipoproteins are suspected to have atherogenic potentiality.