Abstract

Mitochondrial dysfunction has been well established to occur in Parkinson's disease (PD) and appears to play a role in the pathogenesis of the disorder. A key component of the mitochondrial electron transport chain (ETC) is coenzyme Q₁₀, which not only serves as the electron acceptor for complexes I and II of the ETC but is also an antioxidant. In addition to being crucial to the bioenergetics of the cell, mitochondria play a central role in apoptotic cell death through a number of mechanisms, and coenzyme Q₁₀ can affect certain of these processes. Levels of coenzyme Q₁₀ have been reported to be decreased in blood and platelet mitochondria from PD patients. A number of preclinical studies in in vitro and in vivo models of PD have demonstrated that coenzyme Q₁₀ can protect the nigrostriatal dopaminergic system. A phase II trial of coenzyme Q₁₀ in patients with early, untreated PD demonstrated a positive trend for coenzyme Q₁₀ to slow progressive disability that occurs in PD.

Keywords: Coenzyme Q₁₀; Parkinson's disease; Mitochondria; Neuroprotection; Apoptosis

Abbreviations: AIF, apoptosis-inducing factor; ATP, adenosine 5′ triphosphate; C. elegans, Caenorhabditis elegans; CoA, coenzyme A; ETC, electron transport chain; FADH₂, flavin adenine dinucleotide; IAP, inhibitors of apoptosis proteins; MOMP, mitochondrial outer membrane permeabilization; MPP+, 1-methyl-4-phenylpyridinium; MPTP, 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine; NADH, nicotinamide adenine dinucleotide; PD, Parkinson's disease; PTP, permeability transition pore; ROS, reactive oxygen species; SOD2, superoxide dismutase 2 or manganese superoxide dismutase; ΔΨ_m, transmembrane potential; TH-IR, tyrosine hydroxylase immunoreactive; UCP, uncoupling proteins; UPDRS, Unified Parkinson Disease Rating Scale

Article Outline

1. Introduction

2. Mitochondria and bioenergetics and oxidative stress

3. Mitochondria and apoptosis

4. Coenzyme Q₁₀ and Parkinson's disease

5. Preclinical studies of coenzyme Q₁₀ in models of Parkinson's disease

6. Effects of coenzyme Q₁₀ on life span

7. Trials of coenzyme Q₁₀ in Parkinson's disease patients

7.1. Trials in Parkinson's disease patients on medication for Parkinson's disease

7.2. Trials in Parkinson's disease patients with early disease not requiring medication

7.3. Ongoing trials

7.4. Future trials

8. Conclusion

Acknowledgements

References