Erythrocyte antioxidant enzymes in Parkinson's disease

Oxidative stress is incriminated to play a central role in the pathogenesis of Parkinson's disease (PD). Oxidative stress, to which neurons are highly susceptible, is also known to induce oxidative changes in human red blood cells (RBCs), in vivo and in vitro. Earlier studies on oxidative stress in RBCs in patients with PD have yielded controversial results claiming unaltered activity to reduced activity. Using RBC as a model, we have undertaken this study to ascertain the possibility of oxidative damage to the RBCs in PD by measuring the cytosolic antioxidant enzymes viz., superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (G-Px) and glucose-6-phosphate dehydrogenase (G6PD).

Activities of antioxidant enzymes were measured in erythrocytes of 115 PD patients and 37 normal age-matched healthy persons as controls. Enzymes activities were correlated with age of patients, age of onset of disease, duration of disease, United Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr stage.

The SOD, CAT, G-Px and G6PD activities were significantly lower in patients with PD compared to the control. A significant (P<0.05) negative correlation of enzyme activities with Hoehn and Yahr stage of the disease and also with UPDRS score was found.

Results of the present study showed involvement of oxidative stress as one of the risk factors, which can initiate and/or promote neurodegeneration in PD and was correlated to the severity of the disease.