A potential cure for Parkinson's disease has come a significant step closer today with a study showing that it is possible to treat the degenerative brain disorder with cells derived from cloned embryos - a development condemned by the Roman Catholic Church.
The research was carried out on laboratory mice but scientists believe the findings are proof that the techniques could be applied to humans suffering not just from Parkinson's, but a range of other incurable diseases.
Researchers have demonstrated the possibility of treating Parkinson's disease by transplanting laboratory-matured brain cells back into the individual who supplied the skin cells that were turned into cloned embryos - a process known as therapeutic cloning.
"This is an exciting development, as for the first time it may be possible to create a person's own embryonic stem cells to potentially treat Parkinson's disease," said Kieran Breen, director of research at the Parkinson's Disease Society - a charity representing the 120,000 people in Britain affected by the illness.
Dr Breen said: "Stem cell therapy offers great hope for repairing the brain. It may ultimately offer a cure, allowing people to lead a life that is free from the symptoms of Parkinson's disease."
Proof that therapeutic cloning is more than a pipedream will be used by British scientists as justification for their push to expand the boundaries of their research to include the use of animal-human "hybrid" embryos for medical experiments, a process that is bitterly opposed by the Catholic Church.
Scientists say that, because of the shortage of human eggs for research purposes, they need to use cow or rabbit eggs for cloning experiments, and have lobbied hard for it to be allowed under the Human Fertilisation and Embryology Bill currently going through Parliament. Even though the stem cells derived from cloned hybrid embryos will never be used on patients, the practice is condemned by the Church, which wants all MPs to be given a free vote in the Commons.
The latest development, published in the journal Nature Medicine, is further proof-of-principle that therapeutic cloning can effectively treat - and possibly cure - a degenerative brain disorder.
For the first time scientists have been able to create healthy, working brain cells from immature stem cells, derived from embryos cloned from skin cells, and transplant them back into the diseased brain.
The laboratory mice in the study suffered from a type of Parkinson's disease, which is marked by the death of certain nerve cells or neurons in the brain that produce the neurotransmitter dopamine. Skin cells were scraped from the tails of the animals and cloned using mouse eggs, which had their own cell nuclei removed. Stem cells taken from the resulting cloned embryos were grown in the laboratory into mature dopamine-producing brain cells. After transplanting the cells back into the brain, the mice showed significant improvements in a range of experiments designed to test skills that become notably worse in those with Parkinson's disease.
The team of American and Japanese scientists, led by Lorenz Studer of the Sloan-Kettering Institute in New York, were able to produce 187 different strains of embryonic stem cells from 24 Parkinsonian mice. A key finding of the experiment was that there were no signs of tissue rejection because the transplanted brain cells were derived from the same mouse that supplied the skin cell for the cloned embryo.
Professor Robin Lovell-Badge of the Medical Research Council said the study provided further proof-of-principle that therapeutic cloning was a potential treatment for severe disorders of the brain. He said: "The authors were also able to test several independent embryonic stem cell lines corresponding to individual mice, and could show that most seemed to work well. This is very encouraging as it indicates that the cloning process is a sufficiently robust method of reprogramming cells back to an early embryonic state, at least when the early embryos are used to derive embryonic stem cell lines.
"Ideally one of the next steps will be to repeat the whole procedure with a monkey model. This will allow much better tests of functional recovery and safety."
Life With the Disease
"I wish one of these pontificators could get inside my body and see what it feels like. Parkinson's is like being locked in your own body when your mind is still there. I can become as rigid as a plank and my legs won't bend. It's as though there is a ton of cement on my chest and an army of ants crawling up and down my body with spears. It's like being buried alive.
"By the age of 70, three-quarters of those in this country will have Parkinson's disease to some degree as it is a degenerative illness. Once you have it, it never goes into remission. But no one tells you how difficult it is to live with.
"It makes me so angry when I hear academics, theologians or medics arguing about cloning. For me, it is like hearing any hopes we may have of returning to normality being taken away. By mixing ethics with religion and politics, which is a lethal concoction, they are not thinking about the people who have the disease. I feel like saying, 'Get off your high horse.'
"I would not want to stop any process unless it I knew it was categorically not going to work for those who are suffering. I don't believe cloning embryos is like taking life. Parkinson's is such a desperately painful disease. You would have thought that everyone would support anything reasonable to find a cure, and I believe what is being suggested is reasonable."
Geraldine Peacock CBE is a former chair of the Charity Commission. She has had Parkinson's for 18 years.