By Joene Hendry
WESTPORT, Apr 12 (Reuters Health) - Laboratory rats injected with embryonic stem cells as a treatment for spinal cord injuries show better lower extremity function than control animals, according to data presented Monday at the 68th annual meeting of the American Association of Neurological Surgeons in San Francisco, California.
Dr. Todd J. Stewart, from Washington University School of Medicine in St. Louis, Missouri, reported that he and colleagues delivered controlled contusion injuries to the spinal cords of 40 rats, causing complete initial flaccidity followed by some recovery at 3 weeks.
The researchers randomized the injured rats to receive either approximately 1 million embryonic stem cells by injection into the spinal cord at 9 days postinjury or no treatment. The St. Louis team compared the expected return of function in the control group with that seen in the treated rats.
At 2 weeks post-transplant, "the treatment group showed improvement in lower extremity function," Dr. Stewart told Reuters Health in an interview during the meeting. This improvement continued, and at 6 weeks the rats were able to walk but displayed much spasticity.
Conversely, functional improvement in the control group maximized at 3 weeks postinjury and did not improve beyond expectations for this type of spinal injury, Dr. Stewart said.
Additional analysis of the treatment group indicated that the embryonic stem cells differentiated into oligodendrocytes that wrap axons in the spinal cord. This caused myelination, "which may be a partial cause of improvement," Dr. Stewart told Reuters Health.
"We are in the infancy of this research," he noted. He and colleagues
are now researching the underlying mechanisms that may have caused the
functional improvements in the treated rats.