The glutathione system in Parkinson's disease and its progression

Redox dysfunctions and neuro-oxidative stress play a major role in the pathophysiology and progression of Parkinson's disease (PD). Glutathione (GSH) and the reduced/oxidized glutathione (GSH/GSSG) ratio are lowered in oxidative stress conditions and may lead to increased oxidative toxicity. GSH is involved not only in neuro-immune and neuro-oxidative processes, including thiol redox signaling, but also in cell proliferation and differentiation and in the regulation of cell death, including apoptotic pathways. Lowered GSH metabolism and a low GSH/GSSG ratio following oxidative stress are associated with mitochondrial dysfunctions and constitute a critical factor in the neuroinflammatory and neurodegenerative processes accompanying PD. This review provides indirect evidence that GSH redox signaling is associated with the pathophysiology of PD. Nevertheless, it has not been delineated whether GSH redox imbalances are a causative factor in PD or whether PD-associated pathways cause the GSH redox imbalances in PD. The results show that antioxidant approaches, including neuroprotective and anti-neuroinflammatory agents, which neutralize reactive oxygen species, may have therapeutic efficacy in the treatment of PD and its progression.