Antioxidant properties of macrophages toward low-density lipoprotein

Oxidative modification of low-density lipoprotein (LDL) has been implicated in atherosclerosis. Intensive scientific efforts over the last two decades have focused on the elucidation of the mechanisms by which LDL is oxidized in vivo. A wealth of in vitro studies has demonstrated that the cell types present in atherosclerotic lesions, including monocyte/macrophages, quanti tatively one of the most important cell types in plaque development, promot e LDL oxidation. The mechanisms of cellular prooxidant activities hale been extensively investigated. Fewer studies have addressed possible protective properties of the cells in LDL oxidation. This review summarizes recent ob servations of antioxidant, and potentially antiatherogenic, activities of m acrophages toward LDL, including macrophage-mediated detoxification of lipi d and protein hydroperoxides, metal sequestration and the generation of com pounds pounds with antioxidant properties. These activities could contribut e to the net effect of macrophages on deleterious LDL oxidation and to the complex role of these cells in lesion development. (C) 2001, Elsevier Scien ce Inc.