[Coenzyme Q10 in Parkinson's disease. Symptomatic or neuroprotective effects?]

Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive loss of dopaminergic neurons within the substantia nigra pars compacta. Experimental and clinical data point to a defect of the mitochondrial respiratory chain as a major pathogenetic factor in PD. Although the restoration of mitochondrial respiration and reduction of oxidative stress by coenzyme Q(10) (CoQ10) could induce neuroprotective effects against the dopaminergic cell death in PD, these effects of CoQ10 could also improve the dopaminergic dysfunction. Thus CoQ10 might theoretically exert both neuroprotective and symptomatic effects in PD. Current data from controlled clinical trials are not sufficient to answer conclusively whether CoQ10 is neuroprotective in PD. Moreover, several open and controlled pilot studies on symptomatic effects of CoQ10 revealed inconsistent results. A recent randomized, double-blind, placebo-controlled trial showed no symptomatic effects in PD. CoQ10 is well tolerated and safe as both monotherapy and add-on medication in PD patients. The present review discusses the current knowledge on neuroprotective and symptomatic actions of CoQ10 in PD.