Treatment with adult stem cells has cured mice suffering with a form of multiple sclerosis, say Italian researchers. Almost a third of the mice recovered completely from paralysis of their back legs, and the rest all showed substantial improvement.
"It was amazing," says Angelo Vescovi, of the San Raffaele Hospital in Milan. He has now begun experiments giving human adult stem cells to monkeys with the nerve and brain damage seen in MS. But he warns that success in mice does not guarantee success in humans: "I wouldn't want to raise expectations."
Vescovi, Gianvito Martino and colleagues injected the diseased mice with stem cells that had been extracted from the brains of adult mice and multiplied in the lab. The cells were injected in the bloodstream or spinal cord.
Postmortems on the mice showed that the stem cells had migrated to and then repaired damaged areas of the nerves and brain. In particular, the myelin sheaths of nerve cells were restored, after having been worn away.
Seek and repair
Demonstrating that stem cells can locate and repair a multitude of damaged sites by themselves is highly significant for the treatment of MS. "The problem with MS is that we don't know where the lesions are," says Vescovi.
Vescovi stresses that his team's apparent success with adult stem cells should not used as a reason to halt research on embryonic stem cells. Pro-life groups object to research on ESCs because this involves the destruction of embryos aged up to 14 days. These groups argue that adult stem cells are just as promising for medical research.
Although Vescovi does not think embryos should created solely to supply stem cells, he believes it is justified to extract them from spare IVF embryos that would otherwise be "put down the sink".
The European parliament last week voted for draconian new laws to restrict research on embryonic stem cells and on cloning of cells to create tissues for transplant. But the most restrictive measures could be removed as the proposed laws pass through subsequent stages of the legislative process.
Journal reference: Nature (vol 422, p 688)
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