Stem cells restore mobility in paralyzed mice
IRVINE, California - In what is a most promising breakthrough in the effectiveness of the stem cell therapy researchers have found that these cells aid in the recovery of mice with spinal cord injuries.
The findings of the study are to be published next week, but they appear online in the Proceedings of the National Academy of Sciences Early Edition. Researchers at UC Irvine Reeve-Irvine Research Center injected adult human neural stem cells into mice that had been deliberately injured at the level of the spinal cord and consequently had limited mobility. Brian Cummings, Aileen Anderson and colleagues found that these stem cells caused the regeneration of the myelin sheath around the damaged nerves. Myelin is the outer covering of a nerve that is responsible for the conduction of electric signals from one nerve to the next. When myelin around a nerve is damaged or torn away, it results in the development of severe sensory and motor paralysis.
“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,” said Cummings adding that their initial goal was to find out whether these cells would be able to respond to the injury on their own. The researchers also found that the stem cells differentiated into new neurons and caused the reestablishment of synaptic connections with other neurons.
Mice that were injected with the stem cells within nine days of being injured recovered sufficiently to be able to walk, while the mice that did not receive these cells had little or no improvement. Sixteen weeks after the mice were given stem cells, the researchers killed the cells off by using diphtheria toxin, which is fatal only to human cells and not to mice.
They found that the improvement in the walking was compromised suggesting that the human stem cells were responsible for the dramatic improvement. “This work is a promising first step, and supports the need to study multiple stem cell types for the possibility of treating of human neurological injury and disease,” said Anderson.
The adult human neural stem cells used in the study were provided by StemCells Inc. in Palo Alto, Calif, whose shares jumped by 20 percent in the backdrop of this news.
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