OMEGA-3-FATTY-ACIDS IN SMOOTH-MUSCLE CELL PHOSPHOLIPIDS INCREASE MEMBRANE CHOLESTEROL EFFLUX

The aim of our work was to determine whether fatty acid modifications in smooth muscle cell phospholipids affect cholesterol efflux and deso rption. [3(H)]Cholesterol was used to label cholesterol pools in the w hole cell or selectively in the plasma membrane. Cells were incubated for 12 h in order to increase oleate, linoleate, arachidonate, eicosap entaenoic acid (EPA) or docosahexaenoic acid (DHA) in phospholipids. C holesterol efflux was monitored using native or tetranitromethane modi fied high-density lipoprotein(3) (HDL(3)). When all cholesterol pools were labeled, the efflux from cells treated with different fatty acids were not different. Plasma membrane cholesterol efflux remained uncha nged after oleate, linoleate or arachidonate treatments, but was marke dly increased after EPA and DHA enrichment, both with native HDL(3) an d with tetranitromethane-high-density lipoprotein. These results sugge st that the positive effects of n-3 fatty acid consumption on the athe rosclerotic process could belinked in part to an increase in plasma me mbrane cholesterol efflux from vascular smooth muscle cells.