WESTPORT, CT (Reuters Health) Nov 7 - Rodents paralyzed by motor neuron disease exhibited motor recovery of their hind limbs following transplantation of neural stem cells into their spinal fluid, researchers reported at The Society for Neuroscience meeting in New Orleans.
Eight weeks after treatment, "12 of the 18 animals gained some movement," Dr. Douglas Kerr, of Johns Hopkins Hospital in Baltimore, told Reuters Health.
Dr. Kerr and colleagues induced lower motor neuron injury in 18 mice and rats infected with the Sindbis virus, which causes complete paralysis of the hind limbs, mimicking the effects of human motor neuron diseases. Dr. Kerr's team used a lumbar puncture to inject tagged embryonic germ cells derived from fetal animals, which can be grown indefinitely in culture, into the spinal fluid of each rodent.
Twelve of the animals displayed functional recovery ranging from trace movement of the hind legs to taking some steps, Dr. Kerr said.
Microscopic review of the animals' spinal cords at 8 weeks post-implant showed that "tagged neural stem cells migrated up and down the spinal cord and into the ventral horn," Dr. Kerr announced. "Five to seven percent of the neural stem cells differentiated into neurons."
Dr. Kerr told Reuters Health that in three of the animals with no recovery, the neural stem cells never made it into the spinal fluid, probably due to the animals' size. He noted that microscopic findings in the other three animals were inconclusive.
The researchers hypothesize that the animals may have recovered because the stem cells acted as expected, by differentiating into neurons. Alternatively, Dr. Kerr speculated, recovery might be due to a trophic effect where "the stem cells supported and improved function of the remaining host neurons."
Either way, these findings "require a lot of further characterization as to why these animals recovered," Dr. Kerr said. "Long term trials on animals are needed prior to human studies."
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