Stem cells to treat multiple sclerosis?

Injections of adult stem cells appear to have cured paralysis in mice affected by a form of multiple sclerosis (MS), a team of Italian researchers reported in Nature last week. The scientists, based at the Stem Cell Research Institute at the San Raffaele Hospital, Milan, hope that a similar treatment may one day help to treat the human form of the disease.

The researchers injected adult brain stem cells into the bloodstream of 15 mice with paralysed back legs. Four of the mice were cured of their paralysis, while the other eleven regained some movement. Team leader Gianvito Martino thinks that the cells are 'guided' within the body to enter the brain and repair damage. 'We just reproduced what occurs naturally in the body' he said. But he stressed that it would take many more years of research to understand the phenomenon, and before the approach could be tried in humans. The team plans to begin trials in primates later this year, using stem cells from human fetuses.

MS is an autoimmune disease, in which the patient's immune system attacks the fatty covering that protects nerve fibres. This process gradually affects the nerve cells' ability to communicate with the brain, causing symptoms such as blurred vision, numbness, muscle weakness and paralysis. The results of the new study were greeted with excitement by some MS researchers, but others warned that the treatment may not help prevent the long term effects of the disease. 'You have to have a way of shutting off the autoimmune disease if the process is ever going to work' said Lawrence Steinman, a neurologist at Stanford University.