Parkinson’s disease, first described in 1817 by an English doctor of the same name, is one of the most common neurodegenerative disorders, affecting roughly 0.3% of western populations. Current treatment options for the disease involve physical therapy, medication and surgery – all of which are useful, but tend to lose effectiveness over time.
The most promising form of therapy – the controversial practice of transplanting stem cells from aborted human fetuses into the brains of sufferers – was soon abandoned due to its low success rate and disagreements over its ethical implications.
Now, a group of researchers from Sweden, determined to follow up on the work conducted by their colleagues, devised a new set-up. This time – humans were replaced by rats. After killing the dopamine-producing cells in certain areas of their subject’s brains, the research team injected them with the same kind of cells, only derived from human embryos. After 5 months, the transplanted cells restored dopamine levels to normal, established the correct pattern of long-distance connections in the brain and became largely indistinguishable from the original cells, lost to the disease.
“The study shows that the cells that we generate from stem cells, they function equally as well as the cells that we find in the brain”, said the leading author of the study Malin Parmar. “These cells have the same ability as the brain’s normal dopamine cells to not only reach, but also to connect to their target area over longer distances. This has been our goal for some time, and the next step is to produce the same cells under the necessary regulations for human use”.
Roger Barker of Addenbrooke’s Hospital claims that even though there is much to be excited about, rushed decisions may be counterproductive. “This involves understanding the history of the whole field of cell-based therapies for Parkinson’s disease and some of the mistakes that have happened,” said Barker. “It also requires a knowledge of what the final product should look like and the need to get there in a collaborative way without being tempted to take shortcuts, because a premature clinical trial could impact negatively on the whole field of regenerative medicine.”
Clinical trials should begin as soon as 2017.
Original research article: Shane Grealish, Malin Parmar, et al., 2014, Human ESC-Derived Dopamine Neurons Show Similar Preclinical Efficacy and Potency to Fetal Neurons when grafted in a Rat Model of Parkinson’s Disease. DOI: https://dx.doi.org/10.1016/j.stem.2014.09.017.