Lipid clearance from fatty streak lesions by foam cell migration.

Dietary-induced hypercholesterolemia in swine produces fatty streak lesions in the aortic arch within 15 wks. These lesions, though becoming more extensive in area, do not progress beyond the fatty streak stage up to 30 wks on the diet. The stabilization of these lesions may be attributed, in part, to the extensive migration of foam cells from the lesion into the aortic lumen. Morphological evidence indicates a lumenal movement of these cells. Previous studies (1) indicate that foam cells in these lesions are monocyte-derived. The combined evidence suggests the existence of a monocyte lipid clearance mechanism which may represent an initial response of the blood-vascular system to atherogenesis.