Doctors in Scotland working with British biotech company ReNeuron have injected stem cells into the brain of a man in a pioneering clinical trial to test the safety of a therapy for patients disabled by stroke.
The trial is the first in the world to use neural stem cell therapy in stroke patients, its organizers said on Tuesday, and external experts said it was grounds for "cautious optimism."
Keith Muir of the University of Glasgow's Institute of Neuroscience and Psychology, the principal investigator, said the surgery on the first patient, a man in his 60s, had gone well and he had been discharged from hospital.
"He will be monitored closely for two years, as will all the patients in the trial," said a spokeswoman for the university.
The procedure involves injecting ReNeuron's neural stem cells into patients' brains in the hope they will repair areas damaged by stroke, thereby improving both mental and physical function.
This first trial is designed primarily to test whether the experimental treatment is safe for stroke patients.
"We hope that in future it will lead on to larger studies to determine the effects of stem cells on the disabilities that result from stroke," Muir said in a statement.
The nature of the procedure and the characteristics of the cells mean that patients do not need to take immunosuppressant drugs after receiving treatment, the research team said.
Unlike U.S. company Geron's clinical trial in patients with spinal cord injuries, which started last month, the Scottish study uses stem cells derived from human fetuses rather than embryos.
Fetal stem cells do not have the same flexibility to turn into different tissue types as embryonic ones.
Scientists commenting on news of the trial said it was important to guard against raising expectations of miracle cures for thousands of patients in the near future.
"The current trial will require extensive tests for efficacy and safety," said Darren Griffin, a professor of genetics at Britain's Kent University, who is not involved in the study. "Nevertheless, there is room for cautious optimism."
In total, 12 patients will get ReNeuron's ReN001 cell therapy between six and 24 months after having an ischemic stroke — caused by a blockage of blood flow in the brain — and their progress will be followed for two years in the trial.
If the first study is successful, researchers plan to pursue accelerated clinical development in later-stage clinical trials, focusing initially on more severely disabled stroke patients.
Stem-cell technology is viewed as a highly promising new area of medical science, but it has proved controversial, in part because some cell lines are derived from embryos or fetuses. Other research teams are also working with adult stem cells.
Stroke is the third-largest cause of death and the single largest cause of adult disability in the developed world.
"It's far too early to know if the treatment will be successful, but the very fact that the trial is now under way is a milestone for U.K. stem cell research," said Anthony Hollander, a professor of rheumatology and tissue engineering at Bristol University.
ReNeuron had initially hoped to test its stroke treatment in the United States but switched its efforts to Britain in 2008 following delays at the U.S. Food and Drug Administration regulator.