Reprogramming a person’s own skin cells to replace the cells in the brain that are lost during Parkinson’s disease – also known as a cell-replacement strategy – may be possible, according to a team of researchers from McLean Hospital and Massachusetts General Hospital (both MA, USA).
The study, which has been published in New England Journal of Medicine, describes how the investigators reprogrammed a 69-year-old patient’s skin cells into induced pluripotent stem cells and then differentiated them to take on characteristics of dopaminergic neurons.
“Because the cells come from the patient, they are readily available and can be reprogrammed in such a way that they are not rejected on implantation. This represents a milestone in ‘personalized medicine’ for Parkinson’s disease,” commented senior author, Kwang-Soo Kim (McLean Hospital).
In two separate surgeries that took place in 2017 and 2018, the patient underwent transplantation of the replacement dopamine neurons. Jeffrey Schweitzer (Massachusetts General Hospital), who is the lead author of the study), designed a novel neurosurgical implantation procedure that was minimally invasive to deliver the cells.
Approximately 2 years later, imaging tests revealed that these transplanted cells were functioning correctly as dopaminergic neurons in the brain. Additionally, as the implanted cells originated from the patient, they did not trigger an immune response and were not rejected without the use of an immunosuppressant.
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“We have shown for the first time in this study that these reprogrammed cells are still recognized as self by the patient’s immune system and won’t be rejected,” stated Kim.
These results indicate that this personalized cell-replacement strategy was a technical success, as the cells were observed to survive and function in the intended manner. No side effects were noted by the patient and there were also no signs that the cells caused any unwanted growth or tumors.
According to the team, the patient has experienced improvements in his day-to-day activities and reports an improvement in his quality of life. Routine activities have become possible again, such as tying his shoes and walking with an improved stride.
As these results reflect the experience of one individual person, the investigators caution that it is too early to know whether this personalized cell-replacement strategy is viable. The researchers hope to continue to test this treatment in formal clinical trials.
Sources: Schweitzer JS, Song B, Herrington TM et al. Personalized iPSC-derived dopamine progenitor cells for Parkinson’s disease. N. Engl J. Med. 382, 1926–1932 (2020); https://parkinsonscelltherapy.org/press-release