Oxidized low density lipoprotein stimulates aortic smooth muscle cell proliferation

We have investigated the effects of oxidized low density lipoproteins(Ox-LDL) on aortic smooth muscle cell (SMC) proliferation andthe biosynthesis of glycosphingo-lipids. We found that Ox-LDL exerted a concentration, time, and temperaturedependent alteration of cell proliferation and the biosynthesisof lactosylceramide. At low concentrations (5–10 µg/mlmedium) Ox-LDL stimulated cell proliferation measured by anincrease in the incorporation of ³H-thymidine in cells and thesynthesis of lactosylceramide, but not glucosylceramide synthesis.Oxidized LDL exerted a threefold increase in the incorporationof [³H]-galactose and [³H]-serine in lactosylceramide. The activityof lactosylceramide synthetase; UDP-galactose glucosylceramideß1