Photograph: David Burton/Alamy
Early next year, a radical new treatment for Parkinson’s disease that involves tissue transplants will receive its first trial with patients, including a group from the UK.
The stem cells grown in the laboratory and transformed into nerve cells will be used to replace those destroyed by the disease. Hopefully these will stop the spread of debilitating symptoms.
‘It has taken a long time to get to this stage, but hopefully the results of these studies will mean that, in a few years, we may be able to offer tissue transplants as standard treatments for Parkinson’s,’ said Prof. Roger Barker, of the University of Cambridge. . “It’s certainly a promising approach.”
In the UK, around 145,000 people live with Parkinson’s and around 18,000 new cases are diagnosed each year. The disease is triggered when nerve cells that supply dopamine to the brain begin to die due to a combination of genetic and environmental factors.
Dopamine helps a person control movement. When supplies dwindle, the result is shakiness, stiffness, depression and other symptoms that can end up with patients using a wheelchair or being bedridden. The progress of the disease can be slowed down by the drug L-dopa, which replaces some of the lost dopamine cell function. Treatments become less effective over the years. Scientists have been looking for new approaches for years.
One idea has been to replace dying dopamine cells with unaltered versions, which is being pioneered by several centers around the world. This initially involved using tissue from aborted fetuses that had been donated for medical research.
Fetal tissue contains dopamine-producing cells that can supply the missing chemical, although at least six or seven fetuses are needed to supply enough material for a patient. In studies in Europe, these cells have been injected into the brains of patients with encouraging results. However, other studies in the United States have found such treatments to be much less effective.
The use of tissue from aborted fetuses has been opposed by many on religious grounds. It was also difficult to obtain sufficient supplies for widely used treatments. However, Barker and his team at Cambridge, working in collaboration with scientists led by Prof Malin Parmar of Lund University in Sweden, have developed technology that avoids these problems.
The new approach uses stem cells, from which all cells with specialized functions in the human body are generated. These stem cells can be grown in laboratory cultures. Even better, scientists have learned to turn them into dopamine cells. These will form the core of the transplants that will be carried out next month.
“We now know that putting dopamine cells into the brain will work and the procedure is safe,” Barker said. “There is no longer a problem about supplying enough tissue for us to produce these cells in large numbers in the laboratory. The cost is relatively low. A supply of dopaminergic cells – made from stem cells – has become a standardized product and we have no contaminating cells, which you can get with fetal tissue.
“This means that we are now at a point where we can use stem cell transplants as treatments for Parkinson’s patients, although it will be several years before we know that they work and can be used as standard treatments for Parkinson’s disease.” “.
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The trials will begin in the next few months and continue over the next year. There will be four participants from Sweden and four from the UK. “The cells are in a freezer and ready to go in,” Barker said. “Transplants will be done in Sweden because they have the tools to do it. This will be followed up over the course of the year with further trials.
Scientists expect their tests will take at least two years to complete. They will be followed up by a careful review of the results and any side effects. Provided these proceed satisfactorily, the tissue grafts could be ready for wider use in about five years.
“Younger patients will benefit the most from this therapy,” Barker said. “It will be a one-time treatment, so the complications you get with chronic medications won’t show up, while those advanced therapies that involve deep brain stimulation won’t be needed as often.”