Platelet phospholipase A2 activity in patients with Alzheimer's disease, vascular dementia and ischemic stroke.

Phospholipase A(2) (E.C. 3.1.1.4, PLA(2)) plays an essential role in metabolism of membrane phospholipids, it is related to inflammatory reactions, secretion of amyloid precursor protein and activation of NMDA receptor after ischemia. In the present study we investigated PLA(2) activity in platelets from 37 Alzheimer's disease (AD) patients, 32 vascular dementia (VaD) patients and 32 individuals with ischemic stroke as compared to 27 healthy elderly controls. PLA(2) activity was determined using radiometric assay. Mean platelet PLA(2) activity was increased in individuals with Alzheimer's disease (p < 0.001). In VaD group the enzyme activity was between the values in AD and controls, these differences being significant from both groups. In the group of patients with ischemic stroke mean PLA(2) activity was higher either 48 h after the stroke or 7 days later (in both cases p < 0.001). The results may be particularly interesting in light of the fact, that inhibitors of PLA(2) activity are known.