Platelets, endothelium, and smooth muscle cells in atherosclerosis.

A factor derived from platelets stimulates the proliferation of smooth muscle cells in culture, and is likely important in stimulating smooth muscle proliferative lesions of atherogenesis in vivo. The platelet factor is produced during platelet aggregation when serum is made from whole blood. In vitro, smooth muscle cells are potent aggregating agents for platelets, while endothelial cells can inhibit this aggregating effect. Better understanding of the interactions of platelets, smooth muscle cells, and endothelium would facilitate developing effective means of intervening in or preventing the smooth muscle proliferative lesions of atherosclerosis.