A single dose of adult donor stem cells given to animals that have neurological damage similar to that experienced by adults with a stroke or newborns with cerebral palsy can significantly enhance recovery from these types of injuries, according to research findings presented earlier this month at the Annual Meeting of the American Academy of Neurology in San Diego.

Using a commonly utilized animal model for stroke, researchers from the Medical College of Georgia (MCG) administered a dose of 200,000 to 400,000 human stem cells into the brain of animals that had experienced significant loss of mobility and other functions. stem cells used in the study were a recently discovered type, referred to as multipotent adult progenitor cells.

Treated animals experienced at least 25 percent greater improvement in motor and neurological performance than controls, reports Cesario Borlongan, PhD, a neuroscientist at MCG and the Veterans Affairs Medical Center in Augusta, Ga.

The findings hopefully will translate to incremental but important recovery advances in humans, says study co-author David Hess, MD,chair of the MCG Department of Neurology. He hopes stem cell therapy, along with aggressive physical therapy and possibly the clot-busting drug tissue plasminogen activator (tPA), one day can work synergistically to reduce disability due to stroke, which is the single largest cause of disability among American adults.

"These are not going to be cures, but this level of recovery is significant and could help get somebody out of a bed and into a wheelchair, out of a wheelchair to walking with a cane, or from a cane to walking unassisted. We look at that as a big improvement," Dr. Hess says.

Researchers tested adult animals across a range of standardized tasks, before and after undergoing a surgically-induced stroke, and measured their performance. Control animals and those that received a single injection of stem cells then were evaluated for two months.

The animals treated with stem cells had greater recovery of injured tissue and enhanced performance across the range of tests examining strength, balance, agility and fine motor skills.

"A single dose of the cells produced robust behavioral recovery at an early period post-transplantation, and the recovery was durable, lasting up to two months, which was the length of this study," Dr. Borlongan says. "Furthermore, animals continued to show improvement over time."

In the newborn model of ischemic injury, enhanced recovery occurred within two weeks. Even though less than 1 percent of the transplanted cells were present two months later, animals receiving treatment developed new neurons.

"Up to this point, no treatment approaches can get rid of that ischemic core," Dr. Borlongan says. "But outside of that core is a lining called the penumbra. If you do not treat it over time, the penumbra becomes part of the core. We are able to increase the number of cells surviving along that penumbra even one week after a stroke."

Animals in the cerebral palsy model also experienced at least a 25 percent improvement over controls. Cerebral palsy is a condition caused by an ischemic injury similar to stroke but occurring before or during birth. A larger percentage of donated cells survived and within two weeks matured into neurons in the young, more pliable brains.

Close donor matching seemed unnecessary, Dr. Borlongan says.Unmatched transplants from the same species and genetically identical transplants yielded essentially equal results.

"Given the number of stroke victims each year, it would be a big step forward if a safe and effective stem cell therapy could be produced, conveniently stored, and efficiently delivered on a widespread basis," comments Gil Van Bokkelen, PhD, chairman and CEO of Athersys Inc., a biopharmaceutical company in Cleveland, that funded the research.

In extensive animal testing the mature stem cells have been shown to be safe and do not form tumors or other abnormal tissue, a potential problem seen with embryonic stem cells. In addition, the use of immunosuppressive drugs does not appear to be required, in contrast to other types of stem cell treatment.

The researchers already are working with the U.S. Food and Drug Administration with the goal of beginning clinical trials within the next few years.

Researchers are working toward delivering the stem cells intravenously, an approach they believe will work because the cells naturally migrate to an injury site.

*Toni Baker is director of media relations at the Medical College of Georgia.