Malondialdheyde production features in platelets of Parkinson and Alzheimer patients and in physiological aging

Malondialdheyde (MDA), a marker of free radical-induced lipid peroxidation, was measured in basal condition and after stimulation with a free radical generating system in platelets of Parkinson's (PD) and Alzheimer's (AD) pat ient and in normal subjects of different ages. Superoxide dismutase (SOD) a ctivity was determined to assess the platelet detoxification capacity. In n ormal subjects at any age stimulated MDA levels were significantly higher c ompared with levels of basal MDA and this difference appeared to be constan t at any age, thus suggesting that the susceptibility to peroxidation is no t age dependent. In PD patients a significant increase in basal MDA when co mpared with age-matched controls was found, whereas AD patients showed a de crease of this biochemical parameter. SOD activity was significantly lower in PD patients, but showed no significant difference in AD. These results s uggest that in PD patients, instead of in AD, an extracerebral involvement occurs.