Macrophage foam cells and atherosclerosis

Focal buildup of cholesterol in arteries is the process that produces ather osclerotic plaques, the cause of most coronary artery disease and strokes. Monocyte-derived macrophages are central cells that accumulate this cholest erol in atherosclerotic lesions, a manifestation of the scavenging function of the macrophage. Different types of cholesterol-containing lipid particl es found in atherosclerotic lesions may enter macrophages by a variety of e ndocytic pathways. The fate of cholesterol that enters macrophages determin es whether macrophages help or hinder cholesterol removal from the vessel w all. Macrophages may function to carry cholesterol out of lesions, or to pr ocess the cholesterol for excretion in association with small protein-phosp holipid complexes. Alternatively, macrophages that do not efficiently funct ion to remove cholesterol from lesions may ultimately undergo cell death. S ome cytokines, hormones, and pharmacologic agents show potential to modulat e these processes and may be useful in directing macrophage function in ath erosclerotic lesions towards beneficial rather than harmful effects.