What is "oxysterol"

n. (context organic chemistry English) Any of several oxidized derivatives of sterols

Oxysterols are oxidized derivatives of cholesterol, which may be important in many biological processes, including cholesterol homeostasis, atherosclerosis, sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation, though their roles are poorly understood.

Frying foods in overused oil or smoking cigarettes can oxidize cholesterol, creating oxysterols. It is currently thought that oxysterols may play an important role in atherosclerosis progression: they are likely to promote the synthesis of an extracellular matrix scaffold - via pericyte-like cells in blood vessels - which would be needed for the calcification process (deposition of Ca-phosphate crystals).