A US-based team has reported the outcome after treating one individual with an experimental stem cell therapy.
The therapy involved surgically transplanting new brain cells, made from the patient's own skin, into the brain.
The results, published as a brief report in the New England Journal of Medicine, show that such a surgery is possible and suggest that after two years, the transplanted cells are alive and functioning correctly in the brain.
They also suggest that making brain cells from the patients own cells meant they were still recognised by the patient's immune system and were not rejected.
However, the authors are careful to note that this is the first step towards a new type of treatment and that it is too early to know if this kind of therapy really is as promising as it sounds.
Dr Jeffrey Schweitzer, lead author on the paper, is quoted as saying:
“These results reflect the experience of one individual patient and a formal clinical trial will be required to determine if the therapy is effective.”
The idea behind replacing brain cells
In Parkinson's, brain cells that produce the chemical dopamine are slowly lost over time. At the moment, there are no treatments that have been shown to slow, stop or reverse this.
Scientists now know how to make the type of cell that is lost in Parkinson's. They can even use samples of skin as the basic materials from which to make new dopamine-producing brain cells. Being able to make new cells means it may be possible to replace those lost in Parkinson's and reverse the condition.
However, there are many questions that need to be answered, and obstacles to overcome, before such a therapy could be made widely available. The technique has not yet been shown to be safe and effective in clinical trials.
Professor David Dexter, Deputy Director of Research at Parkinson's UK comments:
"Stem cell-based therapies hold much promise for reversing Parkinson's, but currently, no therapy has been able to achieve this. These therapies have come a long way in the last decade and we are now trying to understand the potential short and long-term benefits, and risk of these treatments for people with Parkinson's.
"Some of the earliest cell transplant therapies in Parkinson's date back to the 1980s, but subsequent trials showed mixed results. Some people did remarkably well, even coming off the medication they had relied on, while others experienced little to no improvements. As this treatment involved just one person, it is difficult to come to any conclusions about its true potential. There are also serious risks involved with any brain surgery.
"We still need to overcome significant hurdles to make stem cell-based therapies widely available. Questions around the time and cost of generating new cells from the individual being treated need answering. But with several ongoing, large-scale studies, the aim is to demonstrate that stem cell-based therapies can reverse Parkinson's and turn them into a reality for 145,000 people living with the condition in the UK today."
A note to remember
This project involved extensive collaboration across multiple institutions, scientists, physicians, and surgeons, which was funded by the patient.
We would advise all those taking part in research studies that you should never be asked to pay to take part in a clinical trial.
Clinical trials into stem cell-based therapies are ongoing. Read about the different types of trials happening around the world and the challenges that still remain on the Parkinson's UK research blog.