Platelet-mediated foam cell formation in atherosclerosis.
The early fatty streak lesions of atherosclerosis are characterized by the presence of cholesteryl ester-loaded macrophages or "foam cells." Platelets are also present in the early lesions of atherosclerosis and are often found in close association with foam cells. We have investigated the hypothesis that platelets contribute to foam cell formation by inducing macrophage cholesteryl ester accumulation. Using an in vitro culture system of human monocyte-derived macrophages and autologous platelets, we have demonstrated a platelet-dependent stimulation of macrophage cholesterol esterification and cholesteryl ester accumulation. The response is specific to platelets and is dependent upon activation of the platelets. An active fraction can be isolated from the releasates of thrombin-stimulated platelets that contain large cholesterol-rich platelet membrane vesicles. The results suggest that platelet-derived free cholesterol is required for platelet-induced macrophage foam cell formation.
Department of Immunology, Research Institute of Scripps Clinic, La Jolla, California.
L K
LK
Curtiss
C A
CA
Dyer
C L
CL
Banka
A S
AS
Black
D001161:Arteriosclerosis / Q000097:blood / Q000473:pathology*; D001792:Blood Platelets / Q000502:physiology*; D002478:Cells, Cultured; D002788:Cholesterol Esters / Q000378:metabolism; D005487:Foam Cells / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D015539:Platelet Activation
D002788:Cholesterol Esters