LONDON -- British scientists said today they have developed a technique to repair damaged brain tissue that could led to new treatments for stroke patients, as well as for Alzheimer's disease.
The scientists, headed by Professor Jeffrey Gray, expect to start clinical trials on humans within a few years, said Dan Charlton, spokesman for the Maudesley Hospital's Institute of Psychiatry.
Gray's team members said they subjected laboratory rats to simulated heart attacks to cause severe brain damage and then injected the rats with brain cells from mice embryos.
The rats recovered completely and performed complex tasks, including navigating through milky water to a platform to avoid drowning.
The breakthrough, the researchers say, is that the injected brain cells - neuroepithelial stems cells, or NESCs - migrated to the damaged sites in the rats' brains and then adopted the characteristics of the dead cells.
"What makes this innovative is that the cells are laboratory-manufactured and that they migrate to the part of the brain which needs repair," Charlton said.
Brain cells, unlike cells in other parts of the body, are not naturally replaced.
The Maudsley team hopes the technique can be used to reverse degenerative brain diseases, including Alzheimer's and Parkinson's, as well as brain damage from strokes and heart attacks.
In 1995, scientists at the Salk Institute in San Diego reported experiments showing that the memories of brain-damaged rats improved after injections with modified skin cells. The injections increased the brain's supply of acetylcholine, a substance reduced in the brains of Alzheimer's patients.
The Salk Institute said it was too early to say if their experiments would lead to a treatment for Alzheimer's.
At present, relatively small numbers of patients with Parkinson's disease, which causes uncontrolled trembling, have been treated with cells from human fetuses.
Gray says his team has also discovered a way of force-growing millions of fetal brain stem cells in the laboratory, dramatically reducing the need for human fetal cells. The technique involves using a cancer gene that switches on below body temperature.
"The ethical news is almost all good," Gray told a London newspaper, The Independent. "All the issues about using aborted fetuses will disappear. ... We can treat a wide range of diseases."
The researchers first published their findings in June in the British journal Neuroscience and publicized them this week after forming a company, ReNeuron, which will fund continued research and sell the product.
The Maudsley team has formed a company in conjunction with Merlin Ventures Ltd., British biotechnology entrepreneurs.
Merlin already is financing three British research projects dealing with aspects of cancer, cardiovascular disease and infectious diseases.