Parkinson’s disease is classified as an incurable disease, with the treatment thereof emphasizing improving quality of life and minimizing symptoms, rather than curing and repairing the damage. Researcher Noa Guzner and neurologist Dr. Zeev Itsekzon tell about an innovative direction in research that may change this in the future.
Parkinson’s disease is a neurodegenerative disease, which causes the gradual degeneration of nerve cells in the brain. This disease mostly damages a particular part of a patient’s brain called the substantia nigra, which is responsible for dopamine production, among other things. This part is vital to fine motor control of the body and affects
The symptoms of the disease normally develop over years and may vary greatly from one person to another. Classical symptoms include asymmetric hand tremors at rest, slowness of motion, muscle stiffness, and instability. Sometimes non-motor symptoms exist as well, including early deterioration of the sense of smell, sleep disorders including “vivid” dreams and movements while sleeping, depression, anxiety, constipation, cognitive disorders up to dementia in late phases of the disease, and more.
Currently, treatment of Parkinson’s disease focuses on improving the patient’s quality of life and the symptoms of the disease, rather than curing it. Existing treatments include medications that directly or indirectly increase brain dopamine levels, supportive care such as physiotherapy, and sometimes even surgery and placement of a brain pacemaker used to stimulate the centers responsible for motor control. Medication and surgical treatments may be highly effective but also harbor neurological and psychological side effects.
Therefore, in recent years, a developing research direction has drawn the attention of Parkinson’s disease physicians. This research focuses on the transplantation of stem cells in an attempt to cure the disease.
Stem cells are human cells that have yet to differentiate into a specific tissue in the body. These cells can differentiate into several types of cells, including dopamine-producing nerve cells – the very same type of cells affected by the disease. Stem cells can be taken from the patient themself (autologous), from a foreign donor (allogeneic), or harvested from embryos. Afterward, these cells are transplanted into various parts of the brain. Usually, the cells are not transplanted into the area damaged by the disease, the substantia nigra, but rather in areas closer to the target areas of dopamine, or simply in more accessible areas.
The effect of stem cells on Parkinson’s disease was extensively studied in animals. Additionally, various studies in humans have also been published with very diverse results, from exacerbation of the disease to treatment success with complete deprescribing. For example, two case studies demonstrated gradual motor improvement over years after embryonic stem cells were transplanted into patients with Parkinson’s disease.
Additionally, a study conducted with seven patients with Parkinson’s disease demonstrated the safety of autologous stem cell transplantation but has also showed that 3 out of the 7 patients experienced an improvement in the Unified Parkinson’s Disease Rating Scale (UPDRS), the purpose of which is to rate the disease severity. Specifically, a decrease was observed in the duration of Off periods, periods of time during the day or the week where the patient experiences a substantial motor decline.
In 2021, the FDA issued a fast-track approval for research with a particular type of stem cells, but stem cell therapy has yet to be approved for Parkinson’s disease, and a major study that examines the efficacy of stem cell therapy versus placebo therapy has yet to launch.
In summary, it appears that stem cell transplantation is a groundbreaking option that may help in improving the quality of life of many patients with Parkinson’s disease in the future, and maybe even contribute to curing the disease. However, we must emphasize that this area of research is still in its infancy and it’s a long road ahead before routine use of this technology is approved. This therapy is currently only available for clinical study participants who meet all threshold requirements.