Levels of reduced and oxidized coenzymeQ-10 and 8-hydroxy-2′-deoxyguanosine in the cerebrospinal fluid of patients with living Parkinson's disease demonstrate that mitochondrial oxidative damage and/or oxidative DNA damage contributes to the neurodegenerative process

The aim of this study was to investigate the possibility that mitochondrial oxidative damage, oxidative DNA damage or both contribute to the neurodegenerative process of Parkinson's disease (PD). We employed high-performance liquid chromatography (HPLC) using an electrochemical detector to measure concentrations of the reduced and oxidized forms of coenzymeQ-10 (CoQ-10) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in the cerebrospinal fluid (CSF) of 20 patients with PD and 20 age-matched controls with no neurological disease. The percentage of oxidized to total CoQ-10 (%CoQ-10) in the CSF of the PD group (80.3 ± 17.9%) was significantly higher than in the control group (68.2 ± 20.4%, P < 0.05). In addition, the concentration of 8-OHdG in the CSF of PD patients was greater than in the CSF of controls (P < 0.0001) and was positively correlated with the duration of illness (r_s = 0.87, P < 0.001). Finally, the %CoQ-10 was correlated with concentrations of 8-OHdG in the CSF of PD patients (r_s = 0.56, P < 0.01). The present study suggests that both mitochondrial oxidative damage and oxidative DNA damage play important roles in the pathogenesis of early PD development.