In lab tests, mice with spinal injuries had some improvements after getting injections of adult human neural stem cells.

The mice showed evidence of spinal-cord-lesion repair and better mobility, report Aileen Anderson, PhD, and colleagues.

”This work is a promising step, and supports the need to study multiple stem cell types for the possibility of treating human neurological injury and disease,” says Anderson in a news release.

Andersonworks at the University of California at Irvine’s departments of physical medicine and rehabilitation, anatomy and neurobiology, and the Reeve-Irvine Research Center.

The study appears in Proceedings of the National Academy of Sciences.

Frist Backs Stem Cell Research

Stem Cell Study

Anderson’s team only studied mice, not people. It’s not known if the results would be the same for people.

Nine days after spinal cord injury, each mouse got four shots.

Some mice got shots of adult human neural stem cells. Those cells can develop into cells of the nervous system, which includes the brain and spinal cord.

For comparison, some spine-injured mice got shots that didn’t include any cells. Other mice got shots of a type of human liver cell, which can’t become part of the nervous system.

Adult stem cells are different from embryonic stem cells. Both types of stem cells can develop into different kinds of cells. Embryonic stem cells may have a wider range of possibilities than adult stem cells.

Some Spinal Healing

The mice that got the stem cells improved in two ways:

—Some repair of spinal damage

—Better movement 16 weeks after the shots were given

The mice used their hind paws to help coordinate movement, states the news release.

The mice in the comparison groups didn’t show either benefit.

Next, the mice got a shot of diphtheria toxin. That killed the human cells. Afterward, improvements faded for the stem cell group.

That suggests that the human stem cells played a role in the mice’s progress, but the process isn’t clear yet, the researchers write.

Stem Cells’ Actions

The human adult neural stem cells did three things in the study, according to Anderson’s team:

—Survived the injection.

—Migrated to the right spot on the spine.

—Formed a type of cell that restored a protective coating called myelin that had been stripped away by spinal damage.

In past studies, human neural stem cells have been coaxed into becoming specific cell types before transplantation, notes the news release.

“We set out to find whether these cells would be able to respond to the injury in an appropriate and beneficial way on their own,” says researcher Brian Cummings, PhD, in the news release.

“We were excited to find that the cells responded to the damage by making appropriate new cells that could assist in repair. This study supports the possibility that formation of new myelin and new neurons may contribute to recovery,” he continues.

Cummings works in the physical medicine and rehabilitation department of the University of California, Irvine.

Two of the other researchers work at StemCells Inc., which stands to profit from this research, the journal states.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Cummings, B. Proceedings of the National Academy of Sciences, Sept. 27, 2005; vol 102: pp 14069-14074. News release, University of California, Irvine. News release, Proceedings of the National Academy of Sciences.