In contrast to vitamin E, HDL, apoA-I, and apoA-I mimetic peptides have been shown to prevent LDL oxidation in cell-free systems and in the artery wall co culture studies. HDL, apoA-I, and apoA-I mimetics have been shown to decrease lesions and improve vascular reactivity in animal models of atherosclerosis and in humans. HDL cholesterol promotes cholesterol efflux from extra hepatic tissues and thus can reduce the transformation of macrophages into foam cells and thus reduce fatty streak (foam cell)