April 11 is World Parkinson's Day. Parkinson's disease, characterized by tremors in the hands and feet and gradual paralysis of the body, is considered one of the three major geriatric brain disorders alongside dementia and stroke. With the intensification of aging, the number of Parkinson's disease patients in South Korea has been increasing every year, reaching 125,526 as of 2023.
Parkinson's disease is a degenerative brain disorder that causes tremors in the hands and feet as dopamine nerve cells decrease, resulting in a heavier walking gait. Notable figures such as boxer Muhammad Ali and Pope John Paul II have suffered from it. Dopamine is a neurotransmitter responsible for involuntary muscle movements.
The medical community reports that a complex interplay of genetic and environmental factors contributes to the onset of Parkinson's disease. Since the causes of the disease have not yet been fully identified, there is no fundamental cure. Currently, treatments have been developed using medication that administers levodopa, a substance that becomes dopamine, and deep brain stimulation, which applies electrical stimulation to the brain, but they only slow the progression of symptoms.
Recently, research and development aimed at fundamentally treating Parkinson's disease has been actively progressing. One area of focus is stem cells. The aim is to revive dead dopamine nerve cells with stem cells as Parkinson's disease progresses.
Professor Lee Pil-hyu of Severance Hospital and Professor Jang Jin-woo of Korea University Anam Hospital conducted clinical trials with 12 Parkinson's disease patients using S.Biomedics' stem cell treatment, confirming improvements in symptoms. This treatment is derived from embryonic stem cells, which are primitive cells capable of growing into all tissues and organs of the body.
According to results presented by S.Biomedics at an international conference held in Vienna, Austria, earlier this month, both the low-dose and high-dose treatment groups saw improvements in motor function scores of up to 28.9% compared to pre-implantation. Mental and emotional symptoms, as well as autonomic nervous symptoms, were also significantly improved in both low-dose and high-dose groups.
In particular, after analyzing brain imaging images one year after the stem cell treatment implantation, there was an increased expression of dopamine transporters compared to before. Professor Kim Dong-wook of Yonsei University College of Medicine, the developer of the stem cell treatment, noted, "This suggests that the stem cells survive in the brain, mature into dopamine nerve cells, and form consolidations with surrounding areas and synapses (the connections between nerve cells)," adding that, "This can be seen as strong evidence for the fundamental therapeutic mechanism that replaces dead dopamine nerve cells in Parkinson's disease."
Research is also actively being conducted to identify substances that trigger Parkinson's disease to find treatment clues. Professor Zhen Tao Zhang of Wuhan University in China announced in the international journal 'PLoS Biology' in February that a cholesterol metabolite, 24-OHC, plays a significant role in the onset of Parkinson's disease in mice. The research team reported that blocking or preventing the production of this substance could be an effective strategy for treating Parkinson's disease.
Previously, a joint research team from the Institute for Basic Science, Korea Institute of Science and Technology (KIST), and Asan Medical Center reported that they first identified that a neurotransmitter called gamma-aminobutyric acid (GABA), secreted from non-neuronal cells in the brain known as glial cells, puts dopamine-secreting nerve cells to sleep, causing Parkinson's disease.
The research team reported that after inducing Parkinson's disease in mice and administering a GABA inhibitor, dopamine production was facilitated, resulting in improved motor function. In normal mice, inhibiting dopamine-secreting nerve cells reduced their step count, showing Parkinson's symptoms, while conversely, waking the dopamine-secreting nerve cells in Parkinson's mice increased their steps, indicating symptom improvement. They found that dopamine nerve cells are the cause of Parkinson's disease and also identified the substances that trigger it.
The primary symptoms of Parkinson's disease include bradykinesia (slowness of movement), tremors, stiffness, postural instability (difficulty maintaining balance), and mobility problems. Severe non-motor symptoms such as sleeplessness, constipation, and depression can appear years before these motor symptoms.
Professor Yu Dal-ra of Kyunghee University noted, "While the symptoms, onset timing, and progression patterns vary among patients, it is characterized mainly by tremors on one side that start before or are more severe than on the other side while still, along with rigidity and slowness of movement."
Exercise therapy aimed at preventing Parkinson's disease is also under investigation. Neurotransmitter serotonin, generated through exercise or deep breathing, alleviates depression, obsessive-compulsive disorder, insomnia, and panic disorder. Exercise also raises dopamine levels. Medical professionals emphasize that exercise is as important as medication for Parkinson's patients.
Professor Yu Dal-ra said, "Even when Parkinson's disease develops, exercise can slow the progression of symptoms," and recommended exercising for about 30 minutes a day at a moderate intensity that raises one's breath. It is also recommended as an exercise therapy to habitually take walks after meals or do calisthenics regularly to build muscle and relax the joints.
References
PLoS Biology (2025) DOI: https://doi.org/10.1371/journal.pbio.3002974
Nature Reviews Neuroscience (2023) DOI: https://doi.org/10.1038/s41583-023-00724-7