Aluminum promotes the aggregation of Alzheimer's amyloid beta-protein in vitro.

Amyloid beta-protein is the major component of senile plaques in the brains of Alzheimer's disease and has an intrinsic tendency to form insoluble aggregates. The aggregation of amyloid beta-protein has been suggested to enhance its neurotoxicity and to play a key role in the amyloid deposition. Here we show, using gel-electrophoresis and immunoblotting, that the aggregation of synthetic amyloid beta-protein (beta 1-40) is promoted by aluminum, a suspected risk factor in Alzheimer's disease. High molecular weight aggregates were observed, and the amount of precipitated protein was estimated using high performance liquid chromatography. The results suggest the possibility that aluminum directly influences the process of aggregation and the deposition of senile plaques.