Parkinson’s disease (PD) is a long-term neurodegenerative disorder of the central nervous system that predominately affects the motor system. Patients affected by PD are deprived of dopamine-producing neurons in the substantia nigra, a specific area of the brain, which leads to a decrease in dopamine levels in their brain. Since low dopamine levels in the brain is linked with the central nervous system, they experience “tremor or shaking, muscle stiffness and slowness of movements”, the common symptoms of PD (Neurology, 2017). With the progress of this disease, particularly with ageing, the patients experience difficulty in walking, talking and even in completing simple tasks (JAMA Neurology, 2017).
Corcos and colleagues at Northwestern Medicine and University of Denver have found out that for patients with early-stage PD, performing high-intensity exercise three times a week, decreased the worsening of the motor symptoms (JAMA Neurology, 2017). According to them “exercise is the medicine” and the optimal exercise regimes for patients affected by PD should be designed based on a cardiologist-supervised graded exercise test.
Zhou, Barkow and Freed at the University of Colorado Anschutz Medical Campus using a mice model have shown that exercise could stop accumulation of the neuronal protein alpha-synuclein in brain cells (PLOS ONE, 2017). They believed that clumps of alpha-synuclein play a central role in the death of brain cells associated with PD. Keqiang Ye at Emory University, USA and his colleagues have discovered that alpha-synuclein, a sticky protein, is a pivot for the damage of brain cells in patient’s affected by PD and blocks signals that are important for brain growth. They have demonstrated that alpha-synuclein binds and interferes with TrkB, the receptor for BDNF (brain derived neurotrophic factor) thus creating a “tug of war” between the alpha-synuclein and BDNF for their dominance over the TrkB (PNAS, 2017). According to Zhou and Freed, lack of DJ-1 gene has declined the ability of the mice to run while exercise increased brain and muscle expression by turning on the protective gene DJ-1 and prevents the accumulation of the neuronal protein alpha-synuclein in the brain cells (PLOS ONE, 2017).
Based on their experiments Zhou, Barkow and Freed showed that exercise is likely to prevent brain cells from dying (PLOS ONE, 2017). Since dopamine is the critical component determining the activity of brain cells, they are working towards the conversion of human embryonic stem cells to dopamine neurons as this will open up new avenues to produce sufficient amount of dopamine cells that are necessary for transplant. Researchers at the Department of Medical Biochemistry and Biophysics, Karolinska Institute, lead by Prof. Ernest Arenas, have shown that it possible to manipulate the gene expression of non-neuronal cells (glial cells) in the brain to produce new dopamine neurons (Nature Biotechnology, 2017).
T.S.N. Sankara Narayanan
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