Decreased platelet phospholipase A2 activity in Alzheimer's disease and mild cognitive Impairment

We investigated the activity of phospholipase A₂ (PLA₂) in platelets from patients with Alzheimer’s disease (AD), in healthy elderly controls and in individuals with mild cognitive impairment (MCI). PLA₂ activity was significantly lower in AD than in MCI patients and controls. MCI showed mean PLA2 values between AD and controls. Lower PLA₂ activity was significantly correlated with a worse cognitive performance as rated by the MMSE and CAMDEX. Our data replicate previous findings of reduced PLA₂ activity in AD and further suggests that PLA₂ activity may also be decreased in non-demented memory impaired subjects. PLA₂ activity in platelets may reflect its activity in the brain, considering previous evidence of reduced PLA₂ in post-mortem AD brains, and in vivo spectroscopy data suggesting reduced cortical phospholipid turnover in AD.