Evidence for two metabolic pools of arterial cholesteryl esters in developing experimental atherosclerosis in the rabbit.

A major feature of the development of atherosclerotic lesions in the major arteries of man and most animals is a very large increase in the amounts of cholesteryl esters in the smooth-muscle cells of the tunica intima. The cholesterol moiety of cholesteryl esters is derived almost exclusively from lipoproteins of the blood, whereas the fatty acid portion may originate both from the blood and by synthesis de novo and chain elongation in the arterial cells. Between 20 and 50 % of the cholesteryl esters which accumulate in atherosclerosis of the rabbit aorta arise by esterification of cholesterol with fatty acid derived from the blood. In the experiments reported here, the rates of esterification of cholesterol by [3H]oleic acid in perfused rabbit aortas were measured at different stages in the development of fatty-streak lesions of atherosclerosis. The results suggest the formation of more than one metabolic pool of arterial cholesteryl esters.