Platelet secretion of beta-amyloid is increased in hypercholesterolaemia

Tissue accumulation of the cytotoxic beta-amyloid peptide (Abeta) occurs in Alzheimer's disease (AD), one possible source being the platelet. AD and cardiovascular disease may share some risk factors, including hypercholesterolaemia which is associated with increased platelet activity. We examined platelet Abeta release under resting and collagen-stimulated conditions in normocholesterolaemic and hypercholesterolaemic individuals. Resting platelet Abeta efflux was greater in hypercholesterolaemics than in normocholesterolaemics. Collagen-stimulated Abeta release was concentration-dependent and increased in hypercholesterolaemics. Resting Abeta release correlated positively with plasma total cholesterol and low-density lipoprotein (LDL) cholesterol, and inversely with platelet count. These data indicate that abnormal platelet Abeta release occurs in hypercholesterolaemia.