Sphingomyelin suppresses the binding and utilization of low density lipoproteins by skin fibroblasts

Cultured human skin fibroblasts incubated at 37°C with sonically dispersed, positively charged liposomes containing sphingomyelin internalized and metabolized the phospholipid. Sphingomyelin incorporation into the cells produced a reduction in low density lipoprotein binding and degradation. Lecithin-containing liposomes were much less effective. In addition, incubation with sphingomyelin resulted in a marked increase in acetate incorporation into sterol. These results suggest that sphingomyelin, which is required by cells for membrane synthesis, can influence the regulation of the cell surface low density lipoprotein receptor and intracellular cholesterol balance.