Involvement of cholesterol in the pathogenesis of Alzheimer's disease: role of statins.

Alzheimer's disease (AD) is a slowly, progressive neurodegenerative disorder that is the most common cause of dementia in elderly people. On the other hand, cerebrovascular disease (CVD) and increased levels of cholesterol are related to a high risk of cognitive impairment and dementia. It seems that both groups of dementias are not sharply separated and involvement of cholesterol in the pathogenesis of both types of dementia is suggested. Increasing number of reports indicate that there is a connection between serum cholesterol level and risk of AD and preclinical studies indicate involvement of cholesterol in amyloid-beta protein (Abeta) production. On the other hand, the clinical role of statins in prevention or treatment of AD is not yet established. The influence of statins on AD could be indirect through decreasing serum cholesterol levels and the incidence of CVD or direct by influencing cellular mechanisms in the brain involved in Abeta production and apoptosis.