Paralysed mice regain movement after stem cell treatment

New treatments for paralysis could follow a discovery made by scientists at the Johns Hopkins University in Baltimore, US, that human embryonic stem cells 'cured' paralysis in mice and rats. The stem cells were taken from aborted human fetuses.

Mice and rats were infected with a virus which caused damage to their spinal nerve cells and left them paralysed, with symptoms similar to those associated with motor neurone disease. A solution containing human embryonic stem cells was later infused into the spinal fluid of the animals. The stem cells travelled to the damaged areas of the spine, and some developed as healthy new nerve cells. They also released proteins that encouraged regeneration of existing mature nerve cells.

Most of the animals recovered some function. Dr Douglas Kerr, a neurologist who led the study, said 'they are not completely normal but they can begin to move their hind limbs under them and some can bear weight'. He stated that the researchers were being 'cautiously aggressive' as they wanted their work to advance as fast as possible. Professor John Gearhart, who was also involved in the study, believes that the experiment in mice and rats shows that embryonic stem cells can be used to treat conditions where nerve cells have been damaged and would not normally regenerate.    

The researchers believe that clinical trials on humans could begin within three years and they hope that their research might convince legislators of the value of stem cell research. They have shown a tape of the partially cured animals to Tommy Thompson, the US Health and Human Services secretary, who is currently conducting a review of stem cell technology for the president.