MALONDIALDEHYDE-MODIFIED HDL LEADS TO ACCUMULATION OF CHOLESTEROL IN RAT-LIVER ENDOTHELIAL-CELLS

In order to study in vivo the effect of modified high density lipoprot ein (HDL) on the movement of free cholesterol to liver cells and bile, we injected i.v. into rats, native or malondialdehyde modified HDL la belled with [C-14]cholesterol. Bile analysis indicated that the contri bution of labelled cholesterol to bile acid secretion was diminished i n the group receiving MDA-modified HDL when compared to control group. On the other hand, the liver analysis revealed higher radioactivity i n the treated group. A separation of liver cells into parenchymal, end othelial, and kupffer at 90 min after the injection of MDA-modified HD L or native HDL indicated that the endothelial cell uptake of labelled free cholesterol from MDA-modified HDL was 2.6-fold higher than for n ative HDL. It is suggested that liver endothelial cells may be involve d in the protection against atherogenoic oxidized lipoprotein. However , with regard to our finding, the uptake of cholesterol from modified HDL was detrimental to bile acid secretion. (C) 1995 Academic Press, I nc.