Oxidative DNA damage in leukocytes of de novo and treated patients with Parkinson's disease

Evidence suggests the involvement of oxidative stress in the pathogenesis of Parkinson's disease (PD) and markers of oxidative DNA damage are increased in CNS and in peripheral tissues of patients with PD. In vitro studies have shown that levodopa can generate toxic oxidative metabolites but no evidence of levodopa-induced oxidative stress has been reported in vivo. We evaluated, by means of the Comet assay, DNA oxidative damage in leukocytes of de novo PD patients, dopaminergic-treated PD patients and normal subjects. Compared with controls, the level of single strand breaks, due to oxidized bases, was higher in patients with PD (p<0.05), whereas no difference was observed among the subgroups of patients. These data confirm the presence of oxidative damage to DNA in leukocytes of PD patients independently on pharmacological treatment.