Stem Cell Therapy Outcomes in Parkinson's Disease: A Clinical Review
Background / Problem
Parkinson's disease results from degeneration of the brain cells that produce dopamine, reducing dopamine levels and disrupting movement control — manifesting as hand tremors, difficulty moving, and impaired facial muscle control.
Because brain cells have very limited regenerative capacity, this degeneration is often permanent. Current drug treatment focuses on replacing lost dopamine, but many patients experience side effects. This piece reviews the role of stem cells as an option aimed at restoring neuronal function.
Approach & Mechanism
Stem cells used for Parkinson's disease can be hematopoietic or mesenchymal, and are studied for two therapeutic pathways: (1) differentiating into new neurons to replace damaged ones, and (2) secreting factors that reduce inflammation and stimulate regeneration of existing neurons. Parkinson's is an attractive target because degeneration affects only one type of dopamine-producing neuron.
- 1Understand the degeneration of dopamine-producing neurons
- 2Develop techniques such as genetically modifying MSCs to emphasize dopamine production
- 3Test in vitro and in animal models (mice and monkeys) before human use
- 4Conduct studies in actual patients — currently the subject of many ongoing trials
Outcomes
Stem cell transplantation for Parkinson's began nearly 20 years ago but was previously limited by technology. It has since been reported that stimulated stem cells can produce dopamine in vitro, and animal studies in mice and monkeys have reduced abnormal movement symptoms without serious side effects. Use in actual patients remains under study.
- Stimulated stem cells can produce dopamine in vitro
- Animal studies (mice and monkeys) reduced abnormal movement without serious side effects
- Studies in actual patients are still underway — not yet a standard treatment
Key Findings / Insights
- Stem cells may support the neuronal environment through paracrine secretion of regenerative factors
- Newer techniques, such as genetically modifying cells to emphasize dopamine production, improve the prospect of a treatment effect
- Large clinical trials are needed to confirm efficacy and safety in patients
References
- Kitada M, Dezawa M. Parkinson's disease and mesenchymal stem cells: potential for cell-based therapy. Parkinson's Disease. 2012;2012:873706.
- Inden M, Yanagisawa D, Hijioka M, Kitamura Y. Therapeutic effects of mesenchymal stem cells for Parkinson's disease. Ann Neurodegener Dis. 2016;1(1):1002-9.
- Gravitz L. The promise and potential of stem cells in Parkinson's disease. Nature, Sep 2021. https://www.nature.com/articles/d41586-021-02622-3
Related Resources
Frequently Asked Questions (FAQs)
Can stem cell therapy cure Parkinson's disease?
Stem cell therapy is currently still under study, aimed at slowing and relieving symptoms rather than curing the disease, and should be undertaken under specialist medical supervision.