Impact of Amyloid-β on Platelet Mitochondrial Function and Platelet-Mediated Amyloid Aggregation in Alzheimer's Disease

Background: Alzheimer's disease (AD) is characterized by an accumulation of amyloid beta (A beta) peptides in the brain and mitochondrial dysfunction. Platelet activation is enhanced in AD and platelets contribute to AD pathology by their ability to facilitate soluble A beta to form A beta aggregates. Thus, anti-platelet therapy reduces the formation of cerebral amyloid angiopathy in AD transgenic mice. Platelet mitochondrial dysfunction plays a regulatory role in thrombotic response, but its significance in AD is unknown and explored herein. Methods: The effects of A beta-mediated mitochondrial dysfunction in platelets were investigated in vitro. Results: A beta 40 stimulation of human platelets led to elevated reactive oxygen species (ROS) and superoxide production, while reduced mitochondrial membrane potential and oxygen consumption rate. Enhanced mitochondrial dysfunction triggered platelet-mediated A beta 40 aggregate formation through GPVI-mediated ROS production, leading to enhanced integrin alpha IIb beta(3) activation during synergistic stimulation from ADP and A beta 40. A beta 40 aggregate formation of human and murine (APP23) platelets were comparable to controls and could be reduced by the antioxidant vitamin C. Conclusions: Mitochondrial dysfunction contributes to platelet-mediated A beta aggregate formation and might be a promising target to limit platelet activation exaggerated pathological manifestations in AD.