Stem cell transplantation for treatment of Parkinson disease is complex and requires both surgery and acquisition of stem cells. Research using stem cells in the context of Parkinson disease began in rats almost 40 years ago, with results promising enough to prompt the earliest human studies about 30 years ago.
There are a few different sources used for acquiring dopaminergic cells for human stem cell transplant in Parkinson disease. Fetal dopaminergic neurons and autologous dopamine secreting cells have been used, and studies using bone marrow-derived mesenchymal stem cells and bone marrow-derived embryonic stem cells have been described, with recent research favoring the use of dopaminergic neurons derived from pluripotent stem cells or reprogrammed adult somatic cells.
Currently, there are data from small human trials, a few of which provide detailed findings acquired over 10-years posttransplant. Currently, there are several ongoing human trials, including work that is being done by TRANSEURO, a European research consortium.1
Clinical and pathological results
Long-term outcomes have been followed and comprehensively reported for several patients who received fetal transplants for Parkinson disease. A study published in JAMA Neurology2 describes two patients who received intrastriatal grafts of human fetal ventral mesencephalic tissue rich in dopaminergic neuroblasts. The patients were part of a study in Lund, Sweden, which was one of the first open-label trials of fetal dopaminergic cell transplantation in Parkinson disease.
The two patients were assessed 18 and 15 years posttransplantation. The patient who was assessed 18 years postgrafting demonstrated sustained motor benefits, reported no fluctuations, remained free of any pharmacological dopamine replacement therapy, and is independent in all activities of daily living. His graft-induced dyskinesias improved with amantadine hydrochloride and buspirone hydrochloride, and remained present at his 18-year postgraft assessment, but were less severe than his levodopa-induced dyskinesias prior to transplant.
1. transEUro. Innovative Approach for the Treatment of Parkinson Disease. http://www.transeuro.org.uk. Accessed October 1, 2018.
2. Kefalopoulou Z, Politis M, Piccini P. Long-term clinical outcome of fetal cell transplantation for Parkinson disease: two case reports. JAMA Neurol. 2014;71:83-87.
3. Bega D, Krainc D. Long-term clinical outcomes after fetal cell transplantation in Parkinson disease: implications for the future of cell therapy. JAMA. 2014;311:617-618.
4. Kordower JH, Olanow CW. Fetal grafts for Parkinson disease: decades in the making. Proc Natl Acad Sci USA. 2016;113:6332-6334.
5. Rocco M, Juri C. Is treatment with stem cells effective in Parkinson disease? Medwave. 2018;18:e7242.