Comparative studies on human skin fibroblasts: life span and lipid metabolism in medium containing fetal bovine or human serum.

Three strains of human skin fibroblasts were cultivated in nutrient medium supplemented either with human serum or fetal bovine serum, and growth and lipid synthesis were compared. Rates of cellular growth were similar in both kinds of medium, but the replicative life spans of all three strains were curtailed significantly in human-serum medium. Incorporation of label into the major classes of neutral lipids from [14C]acetate and 3H2O was increased also in human-serum medium. Since human serum contained higher concentrations of cholesterol known to reduce endogenous cholesterol synthesis, these results were unexpected. Nonlipid factors in human serum may account for the shortened cellular life spans and increased lipogenesis and perhaps for the potential to develop atherosclerosis.