Tuesday, 21 January, 2003, 15:18 GMT
Scientists have successfully replaced brain cells damaged by multiple sclerosis (MS), raising hopes of an effective new treatment for the disease.
At present, the technique has only been tested in mice, but it is hoped
the same principle can eventually be applied to humans.
A team from St Vincent's Hospital in Sydney replaced the damaged brain cells with immature 'stem' cells taken from the bone marrow of both mice and humans.
Multiple sclerosis (MS) is a chronic and progressive illness that affects the body's nerves and can render a person disabled.
The disease progresses as a patient loses a type of nerve cell known as an oligodendrocyte, which helps electrical currents to travel around the nervous system by producing the protective myelin sheath that coats the nerves.
As more and more cells are lost, the myelin sheath is damaged, resulting in faulty transmission of nervous signals.
The two-year study used 25 mice to model the effects of multiple sclerosis. Adult stem cells from mice and humans were injected into the mice, five, 10 and 20 days after being isolated from bone marrow.
Signs of oligodendrocyte growth were found in between half and three-quarters of the experiments.
The next step is to determine whether the newly formed brain cells were functional and capable of producing myelin.
Professor Bruce Brew, St Vincent's director of neurology and neurosciences, said: "While we are still some years away from a human application, the fact that we are able to use adult stem cells in this way is extremely important in the development of effective therapies against a variety of brain diseases."
He said there was no guarantee that the treatment could completely reverse symptoms of MS.
But he said there was a "good likelihood" that it could have some positive impact.
Professor Brew said doctors may eventally be able to isolate stem cells from a patient's bone marrow, manipulate them and reinject them to hone in on the damaged area for repairs.
However, the research is based on the principle that stem cells will develop in response to signals generated by brain disease.
Professor Brew said the longer a person suffered from a brain disease, the weaker the signals became and the less likely that the stem cells would differentiate into the required cell.
Mike O'Donovan, chief executive of the UK Multiple Sclerosis Society, said: "The potential for using adult stem cells in the treatment of MS could be very significant.
"These early results certainly appear encouraging and we look forward to studying them in greater detail."
Christine Jones, chief executive of the UK MS Trust, said: "Of course these are very early findings and results demonstrated in mice with the experimental equivalent of MS are not necessarily replicated in people with MS.
"However, stem cell research is very exciting in terms of future therapies
for MS though obviously this study, as the researcher points out, is years
away from application."
© 2003, BBC