Mitochondrial enhancement for neurodegenerative movement disorders: a systematic review of trials involving creatine, coenzyme Q10, idebenone and mitoquinone.

BACKGROUND: Neurodegenerative movement disorders mainly include Parkinson's disease (PD), atypical parkinsonisms, Huntington's disease (HD), and Friedreich's ataxia (FA). With mitochondrial dysfunction observed in these diseases, mitochondrial enhancement such as creatine, coenzyme Q10 (CoQ10) and its analogues (idebenone and mitoquinone) has been regarded as a potential treatment.

AIM: In this paper, we systematically analysed and summarized the efficacy of mitochondrial enhancement in improving motor and other symptoms in neurodegenerative movement disorders.

METHODS: We searched the electronic databases PubMed, EMBASE, CINAHL, Cochrane Library and China National Knowledge Infrastructure until September 2013 for eligible randomized controlled trials (RCTs), as well as unpublished and ongoing trials. We calculated the mean differences for continuous data with 95% confidence intervals and pooled the results using a fixed-effect model, if no significant statistical heterogeneity was found (I(2) < 50%).

RESULTS: We included 16 studies with 1,557 randomized patients, which compared creatine, CoQ10 or its analogues with placebo in motor and other symptoms. No significant improvements were found in the motor symptoms of PD, atypical parkinsonisms or HD patients, while only the high dose of idebenone seems to be promising for motor improvement in FA. Certain benefits are found in other symptoms.

CONCLUSIONS: There is insufficient evidence to support the use of mitochondrial enhancement in patients with neurodegenerative movement disorders. More well-designed RCTs with large samples are required for further confirmation.