Plasma lipid peroxidation in sporadic Parkinson's disease. Role of the L-dopa.

Oxidative stress plays an important role in the pathogenesis of neurodegenerative diseases, such as Parkinson's disease (PD). There are several methods to measure oxidative stress, being lipid peroxidation (LPO) one of the most frequently used. Endogenous plasma LPO was determined by a spectrofluorimetric method in fifty two patients with sporadic PD and in forty controls. To know the maximum capacity of lipids to peroxidate, LPO was also measured after co-incubation with Fe2+/H2O2 (exogenous LPO). All PD patients were taken L-dopa and the effect of this treatment on LPO levels was additionally studied. Urine catecholamines and their main metabolites were also analyzed, and their possible correlation to LPO statistically studied. Endogenous plasma LPO levels were 33% higher in PD group than in control group (P<0.001). Exogenous plasma or oxidizability was also higher in PD patients compared to controls (20%, P<0.05). The intake of L-dopa was negatively dose-related to endogenous and exogenous plasma LPO. In conclusion, plasma of PD patients has elevated levels of LPO and also is more prone to peroxidation than that in the control group. The results also suggest an antioxidant effect of L-dopa.