High density lipoproteinemia due to vigorous physical work inhibits the incorporation of [3H]thymidine and the synthesis of glycosaminoglycans by human aortic smooth muscle cells in culture.

The effect of sera from normolipidemic men engaging in normal physical activity and from high density lipoproteinemic lumberjacks engaging in vigorous physical activity on the incorporation of [3H]thymidine and the synthesis of glycosaminoglycans by human aortic smooth muscle cells in culture was measured. At high concentration (15%) high density lipoproteinemic serum inhibited significantly (P less than 0.001) the incorporation of thymidine. The serum inhibited the synthesis of glycosaminoglycans at all concentrations tested (1--15%) with the most marked inhibition at 10 and 15%. At lower concentrations (1--5%) the inhibition was more pronounced for sulphated glycosaminoglycans than for hyaluronic acid. The inhibition was of the same magnitude for the subclasses (chondroitin, dermatan and heparan sulphates) of sulphated glycosaminoglycans studied. High density lipoproteinemia due to vigorous physical work is postulated as a protective factor against the early biochemical reactions of arterial smooth muscle cells in the development of atherosclerosis.