Lund University researchers followed a Parkinson’s disease patient who had undergone neuronal transplantation, and reported the patient experienced long-term “major clinical benefits,” including the restoration of normal dopamine function. Importantly, transplant-derived cell reinnervation was evident for almost 25 years, although the disease again began to progress some 14 years after transplantation.
The study, “Extensive graft-derived dopaminergic innervation is maintained 24 years after transplantation in the degenerating parkinsonian brain,” was published in Proceedings of the National Academy of Sciences of the United States of America (PNAS).
Transplantation of dopamine neurons derived from embryonic stem cells into the brains of Parkinson’s disease (PD) patients is a promising potential treatment for halting PD progression, as it has been shown that transplanted cells can survive and function in the brains of people with the disease. However, inconsistent findings of PD symptom relief among patients and even unwanted side effects, such as involuntary movements, have limited the use of this technique.
Researchers reported the long-term follow-up of a PD patient who underwent dopamine-producing nerve cell transplantation 24 years prior to his death, and postmortem analysis of the brain. Three years after the procedure, improvement was so impressive that the patient was able to stop medication with L-dopa. Ten years after the operation, brain-imaging results showed that dopamine function was completely normal. Furthermore, transplanted dopamine-producing cells and their normal neural connections were still present almost 25 years after the transplant. However, researchers observed that the procedure’s clinical benefits gradually faded as the disease progressed to other areas of the brain.
“This study is completely unique,” one of the study’s lead authors, Professor Anders Björklund, said in a press release. “No transplanted Parkinson’s patient has ever been followed so closely and over such a long period. The patient was also unique in the sense that the nerve cells were only transplanted to one hemisphere of the brain, which meant that the other, which did not receive any transplant, could function as a control. What we have learnt from the study of this patient will be of great value for future attempts to transplant dopamine-producing nerve cells obtained from stem cells, a new development led by researchers in Lund.”