Alzheimer's disease: Beta amyloid and lipid metabolism.

Amyloid deposits found in brains of Alzheimer's disease, Down's syndrome and normal aged individuals are composed mainly of aggregated amyloid beta (Ab), soluble form which is a normal protein. We previously reported that soluble Ab (sAb) in normal human plasma and cerebrospinal fluid is complexed to high density lipoprotein (HDL). Consequences of sAb association with the HDL and Ab involvement in the lipid turnover are discussed herein.