LIPID-PEROXIDATION AND PLATELET MEMBRANE FLUIDITY - IMPLICATIONS FOR ALZHEIMERS-DISEASE

IN humans, the fluidity of cell membranes generally decreases with age . Unexpectedly, several laboratories have found increased fluidity of platelet membranes (mainly endoplasmic reticulum) in patients with Alz heimer's disease (AD) compared with controls. In the present study, fr ee radical induced lipid peroxidation was found to increase the fluidi ty of platelet membranes. Hydroxyl radicals were generated in the pres ence of Fe2+ and EDTA at low concentrations of ascorbate. It is hypoth esised that platelet membranes are unable to restore their microviscos ity by incorporating cholesterol. There may be a link between the resu lt obtained in this study, the recently discovered decreased cholester ol content of affected AD neuronal membranes, and the increased freque ncy of epsilon 4 apolipoprotein E (a cholesterol carrier) found in AD patients.