Hypercholesterolemia accelerates the Alzheimer's amyloid pathology in a transgenic mouse model

Recent data suggest that cholesterol metabolism is linked to susceptibility to Alzheimer's disease (AD). However, no direct evidence has been reported linking cholesterol metabolism and the pathogenesis of AD. To test the hyp othesis that amyloid beta-peptide (A beta) deposition can be modulated by d iet-induced hypercholesterolemia, we used a transgenic-mouse model for AD a myloidosis and examined the effects of a high-fat/high-cholesterol diet on central nervous system (CNS) A beta accumulation. Our data showed that diet -induced hypercholesterolemia resulted in significantly increased levels of formic acid-extractable A beta peptides in the CNS, Furthermore, the level s of total A beta were strongly correlated with the levels of both plasma a nd CNS total cholesterol. Biochemical analysis revealed that, compared with control, the hypercholesterolemic mice had significantly decreased levels of sAPP alpha and increased levels of C-terminal fragments (beta-CTFs), sug gesting alterations in amyloid precursor protein processing in response to hypercholesterolemia. Neuropathological analysis indicated that the hyperch olesterolemic diet significantly increased beta-amyloid load by increasing both deposit number and size. These data demonstrate that high dietary chol esterol increases A beta accumulation and accelerates the AD-related pathol ogy observed in this animal model. Thus, we propose that diet can be used t o modulate the risk of developing AD. (C) 2000 Academic Press.