Researchers at Mount Sinai School of Medicine and Rush University Medical Center have found even newly transplanted dopamine neurons can get adversely affected as Parkinson's disease progresses.
The finding not only offers a major clue in the nature of Parkinson's disease, but may also pave the way for using transplantation and stem cell therapies, for its treatment.
The research team, led by Dr. C. Warren Olanow, M.D., F. R. C. P (C), Professor and Chairman of Neurology and Director of The Robert and John M. Bendheim Parkinson's Disease Center at Mount Sinai School of Medicine, discovered that after transplanting dopamine cells in to PD patients' brain, the cells developed pathologic changes characteristic of PD, i.e. Lewy bodies. In fact, the dopamine cells ceased their normal functioning, i.e. they reduced staining for dopamine transporter.
For the study the researchers managed to perform an autopsy and for studying brain tissue from a patient who received a dopamine transplant 14 years back.
"We found that newly implanted dopamine cells can also be affected by the Parkinson's disease process. Dopamine cells are transplanted into the brain of PD patients in the hope that they can replace those that degenerate and thereby improve symptoms of the disease," Nature quoted Olanow, as saying.
"This study shows that implanted cells can become affected by the disease process and thereby limits the long-term utility of this approach," he added.
The results indicated that though the patient's condition did improve initially but it deteriorated later.
The findings suggested future implications for the use of stem cells as a treatment for Parkinson's disease and also in finding the cause of PD.
The study counters the existing theory and says that PD is not caused because of a single event but it is a continuous process that can harm newly implanted cells.
"While, on the one hand, these results may sound disappointing, this information is crucially important if we are to develop better therapies for PD. The more knowledge we gain about the nature of the disease, the better our chances to find the cause of why cells degenerate and to develop a treatment that can protect them," said Dr. Olanow.
"These findings also do not mean that transplant strategies such as stem cells can not be made to work - our findings just represent another obstacle that will have to be overcome," he added.
The study appears in the journal Nature Medicine.