Oxidative stress in skin fibroblasts cultures from patients with Parkinson's disease.

BACKGROUND: In the substantia nigra of Parkinson's disease (PD) patients, increased lipid peroxidation, decreased activities of the mitochondrial complex I of the respiratory chain, catalase and glutathione-peroxidase, and decreased levels of reduced glutathione have been reported. These observations suggest that oxidative stress and mitochondrial dysfunction play a role in the neurodegeneration in PD. We assessed enzymatic activities of respiratory chain and other enzymes involved in oxidative processes in skin fibroblasts cultures of patients with PD. METHODS: We studied respiratory chain enzyme activities, activities of total, Cu/Zn- and Mn-superoxide-dismutase, gluthatione-peroxidase and catalase, and coenzyme Q10 levels in skin fibroblasts cultures from 20 Parkinson's disease (PD) patients and 19 age- and sex- matched healthy controls. RESULTS: When compared with controls, PD patients showed significantly lower specific activities for complex V (both corrected by citrate synthase activity and protein concentrations). Oxidized, reduced and total coenzyme Q10 levels (both corrected by citrate synthase and protein concentrations), and activities of total, Cu/Zn- and Mn-superoxide-dismutase, gluthatione-peroxidase and catalase, did not differ significantly between PD-patients and control groups. Values for enzyme activities in the PD group did not correlate with age at onset, duration, scores of the Unified Parkinson's Disease Rating scales and Hoehn-Yahr staging. CONCLUSIONS: The main result of this study was the decreased activity of complex V in PD patients. This complex synthesizes ATP from ADP using an electrochemical gradient generated by complexes I-IV. These results suggest decreased energetic metabolism in fibroblasts of patients with PD.

Oxidative stress in skin fibroblasts cultures of patients with Huntington's disease.

Oxidative stress and mitochondrial dysfunction should play a role in the neurodegeneration in Huntington's disease (HD). The most consistent finding is decreased activity of the mitochondrial complexes II/III and IV of the respiratory chain in the striatum. We assessed enzymatic activities of respiratory chain enzymes and other enzymes involved in oxidative processes in skin fibroblasts cultures of patients with HD. We studied respiratory chain enzyme activities, activities of total, Cu/Zn- and Mn-superoxide-dismutase, glutathione-peroxidase (GPx) and catalase, and coenzyme Q(10) (CoQ(10)) levels in skin fibroblasts cultures from 13 HD patients and 13 age- and sex-matched healthy controls. When compared with controls, HD patients showed significantly lower specific activities for catalase corrected by protein concentrations (P < 0.01). Oxidized, reduced and total CoQ(10) levels (both corrected by citrate synthase (CS) and protein concentrations), and activities of total, Cu/Zn- and Mn-superoxide-dismutase, and gluthatione-peroxidase, did not differ significantly between HD-patients and control groups. Values for enzyme activities in the HD group did not correlate with age at onset and of the disease and with the CAG triplet repeats. The primary finding of this study was the decreased activity of catalase in HD patients, suggesting a possible contribution of catalase, but not of other enzymes related with oxidative stress, to the pathogenesis of this disease.