On the turnover of brain cholesterol in patients with Alzheimer's disease.Abnormal induction of the cholesterol-catabolic enzyme CYP46 in glial cells

Evidence is accumulating for a link between cerebral cholesterol metabolism and Alzheimer's disease (AD). Here we focus on a possible relationship bet ween AD and a newly discovered mechanism for cholesterol eff lux from the b rain, involving conversion of brain cholesterol into 24S-hydroxycholesterol by the neuronal oxidative enzyme CYP46. There was a marked difference in t he distribution of CYP46 in brains of control and AD patients. The neuronal cells were less stained in AD brains than in controls while marked positiv e staining was found in glial cells in AD but not in controls. The dynamic changes in the mechanisms for cholesterol efflux from the brain are of inte rest in relation to the link between brain cholesterol and amyloid P-protei n in AD. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.