A recent successful study into Parkinson's disease has been commented on by a leading charity.
The Parkinson's Disease Society (PDS) spoke of the team from Switzerland who discovered that monkeys which received transplants of their own brain cells had normal levels of dopamine-producing nerve cells, while only less than half were spotted in monkeys that received only the chemical which the cells produce.
It was found that transplanted cells were able to survive in the brain, making contact with the most damaged regions and protecting remaining cells or stimulating growth of new ones.
Director of research and development at the PDS Dr Kieran Breen said: "These exciting new findings offer hope that we may be able to repair the Parkinson's brain using a person's own cells. This would avoid immune rejection and the ethical controversies that surround embryonic cell transplants."
He added that scientists do not know how transplanted nerve cells behave inside the brain, nor do they understand how long these effects can last, though new transplant studies and new developments in stem cell research show "great promise".
One in 500 people in the UK, or around 120,000 individuals, have Parkinson's disease.