Stem cells help paralysed rats to walk

Two new studies carried out using rats have shown that stem cells taken from early embryos could be used to treat spinal injuries. Researchers at the University of California in Irvine, US, used stem cells from human embryos to grow specialised 'nerve insulating' cells to successfully treat paralysed rats with 'bruised' spines.

The transplanted cells, called oligodendrocytes, appeared to stimulate the growth of new nerve cells, as well as re-insulating the damaged ones. The scientists, who presented their findings at the recent BIO 2003 conference in Washington DC, say they now plan to use the technique on people who have suffered recent, localised spinal cord damage.

In a separate study, researchers at the Johns Hopkins University in Maryland, used unspecialised human embryo stem cells to treat rats with injured spinal cords. Team leader Douglas Kerr says that the findings, which will appear in the Journal of Neuroscience, seem to show that the animals' recovery was due to the repair of damaged nerve cells rather than the growth of new ones. 'The stem cell's magic was really their ability to get into the area of injury and snuggle up to those neurons teetering on the brink of death' says Kerr.

The president of US stem cell firm Geron, which funded the University of California study, hopes the results will persuade policy makers not to ban embryo stem cell research. Thomas Okarma says that although ways will have to be found to prevent people from rejecting embryo cell transplants, stem cells from adult tissue have serious limitations as a mass-market treatment because not many can be grown from a single source.

In contrast, 'one cell bank derived from a single embryo produces enough neurons to treat ten million Parkinsons's disease patients' he told delegates at the BIO 2003 conference. The proposed use of cloned cells from early embryos to develop new disease treatments is not funded by the US government, but such research is currently permitted in the private sector. 'The promise of this technology is beginning to be realised' said Okarma. 'That's why we think this battle is worth fighting'.