Does High-Dose Coenzyme Q 10 Improve Oxidative Damage and Clinical Outcomes in Parkinson's Disease?

Abstract

Evidence on the efficacy of high-dose coenzyme Q₁₀ (CoQ₁₀) in Parkinson's disease (PD) is conflicting. An open-label dose-escalation study was performed to examine the effects of CoQ₁₀ on biomarkers of oxidative damage and clinical outcomes in 16 subjects with early idiopathic PD. Each dose (400, 800, 1200, and 2400 mg/day) was consumed daily for 2 weeks. High-dose CoQ₁₀ was well tolerated and improvements in the total Unified Parkinson's Disease Rating Scale (median, 37 vs. 27; p=0.048) were observed following study completion. Plasma F₂-isoprostanes (adjusted for arachidonate) were significantly reduced in the 400–1200 mg/day dose range, but increased at 2400 mg/day dosage. A similar pattern of change was observed with serum phospholipase A₂ activities. Levels of plasma all trans-retinol, plasma total tocopherol, serum uric acid, and serum total cholesterol were unchanged despite an increase in the CoQ₁₀ dosage. Subjects with symptomatic benefits from CoQ₁₀ (decrease in total UPDRS >10 points) had lower baseline plasma ubiquinol (p=0.07, Mann–Whitney U test) and decreased F₂-isoprostanes per unit arachidonate (p=0.04, Wilcoxon Signed-Ranks test). These results lead to the hypothesis that the therapeutic response to CoQ₁₀ depends on baseline levels of ubiquinol and whether the dosage of CoQ₁₀ used can ameliorate the burden of oxidative damage. Antioxid. Redox Signal. 21: 211–217.