WASHINGTON (Reuters) - Immature human nerve cells grew in the spines of injured mice and helped them walk a little better, researchers said on Wednesday in a study they said shows it may be possible to treat patients weeks or months after their accidents.
The study, published in the Public Library of Science journal PLoS ONE, suggests there is a longer period of opportunity than previously thought to treat spinal cord injuries.
It is very difficult to heal damaged spinal cords and most studies have shown that any treatment attempt must take place within days after the injury to do any good.
But a team using StemCells Inc's nerve stem cells taken from aborted fetuses found that even a month after injury, the cells took up residence in the spine, proliferated and helped mice walk better.
The California-based company hopes to begin human tests of the cells in 2011.
The cells are a form of stem cell, the master cells of the body. These are technically adult stem cells, taken from the partly developed brains of fetuses and tested for qualities showing they are destined to form particular types of nerve cells.
Dr. Aileen Anderson of the University of California, Irvine and colleagues tested 37 mice, damaging their spinal cords surgically and then transfusing either the StemCells product, ordinary human skin cells or a placebo.
The cells migrated through the spine, grew and began to function, the researchers said. When tested for coordination, 64 percent of the stem-cell-treated mice walked better, compared to 44 percent of mice treated with ordinary cells and 20 percent of placebo-treated mice.
The report is available at http://dx.plos.org/10.1371/journal.pone.0012272.
"These exciting results demonstrate an expanded window of opportunity for human neural stem cell intervention in spinal cord injury," StemCells Vice President Dr. Stephen Huhn said in a statement.
About 1.25 million Americans have chronic spinal cord injuries. "This latest study provides additional evidence that the use of our human neural stem cells may be a viable treatment approach for them," Huhn said.
Last October, the company said a nerve stem cell product it makes helped rats with an eye disease called macular degeneration [ID:nN19320418].
It is one of a number of companies trying to develop various forms of stem cells into human therapies.
(Reporting by Maggie Fox; Editing by Julie Steenhuysen and Bill Trott)