Pesticides and Parkinson's disease: Current and future perspective

Inappropriate use of pesticides has globally exposed mankind to a number of health hazards. Still their production is rising at the rate of 11 % annually and, has already exceeded more than 5 million tons in 2000 (FAO 2017). Plenty of available data reveals that pesticides exposures through agricultural use and food-preservative residue consumption may lead to neurodegenerative disorders like Parkinson's and Alzheimer's diseases. Parkinson's disease (PD) is a progressive motor impairment and a neurodegenerative disorder, considered as the leading source of motor disability. Pesticides strongly inhibit mitochondrial Complex-I, causing mitochondrial dysfunction and death of dopaminergic neurons in the substantia nigra (SN), thus leading to pathophysiologic implications of PD. Current medical treatment strategies, including pharmacotherapeutics and supportive therapies can only provide symptomatic relief. While complementary and alternative medicines including traditional medicine or acupuncture are considered as beneficial ways of treatment with significant clinical effect. Medically non-responding cases can be treated by surgical means, 'Deep Brain Stimulation'. Cell therapy is also an emerging and promising technology for disease modeling and drug development in PD. Their main aim is to replace and/or support the lost and dying dopaminergic neurons in the SN. Recently I/II clinical phase trial (Japan) have used dopaminergic progenitors generated from induced pluripotent stem (iPS) cells which can unveil a successful cell therapy to treat PD symptoms efficiently. This review focuses on PD caused by pesticides use, current treatment modalities, and ongoing research updates. Since PD is not a cell-autonomous disease rather caused by multiple factors, a combinatorial therapeutic approach may address not only the motor-related symptoms but also non-motor cognitive-behavioral issues.