Lipids in cells of atherosclerotic and uninvolved human aorta. II. Lipid metabolism in primary culture.

[3H]Acetate and [3H]oleate were used to evaluate the rate of lipid synthesis in smooth muscle cells of human aorta. Experiments were carried out in primary cultures derived from the intima and media of unaffected and atherosclerotic vascular segments. The obtained results indicate that the rate of lipid synthesis in cells cultured from fatty streaks, atherosclerotic plaques, and underlying media is higher than in cells cultured from an uninvolved intima and media, respectively. The highest level of the label incorporation was observed in the fraction of phospholipids. In cultures obtained from fatty streaks and plaques, an increased incorporation of the labeled precursors into phospholipids, triglycerides, free sterols, and sterol esters was registered. The highest relative increase occurred in the fraction of sterol esters, the rate of acetate inclusion being five- to sixfold higher compared to the cell cultures derived from unaffected aortic segments. A direct and very close correlation was found between the rate of lipid synthesis and lipid levels in cells of normal and atherosclerotic aorta. The role of intracellular lipid metabolism disorders in the accumulation of excessive fat by "atherosclerotic" cells is discussed in this report.