Abstract
Oxysterols are present in human atherosclerotic plaque and atherogenic plasma low-density lipoprotein (LDL) subfractions, and it has been suggested that they play a role in the initiation and development of atherosclerosis. 27-Hydroxycholesterol, one of the most abundant oxysterols found in atherosclerotic lesions and circulating plasma, is one of the enzymic products of cholesterol catabolic pathways to bile acids, and is involved in the elimination of excess cholesterol from peripheral tissues such as the artery wall. Conversely, oxysterols generated by free radical-mediated oxidation (e.g., C-7 and C-5, 6 oxidation products) are considered to have atherogenic effects on cellular cholesterol metabolism (i.e., biosynthesis, uptake, esterification, and efflux) and blood vessels (vascular reactivity and angiotoxicity). But there is no direct evidence yet in humans that oxysterols contribute to the development of atherosclerosis.
