A treatment derived from human embryonic stem cells improves mobility in rats with spinal cord injuries, providing the first physical evidence that the therapeutic use of these cells can help restore motor skills lost from acute spinal cord tissue damage.
Hans Keirstead and his colleagues in the Reeve-Irvine Research Center at UC Irvine have found that a human embryonic stem cell-derived treatment they developed was successful in restoring the insulation tissue for neurons in rats treated seven days after the initial injury, which led to a recovery of motor skills. But the same treatment did not work on rats that had been injured for 10 months. The findings point to the potential of using stem cell-derived therapies for treatment of spinal cord damage in humans during the very early stages of the injury. The study appears in the May 11 issue of The Journal of Neuroscience.
"We're very excited with these results. They underscore the great potential that stem cells have for treating human disease and injury," Keirstead said. "This study suggests one approach to treating people who've just suffered spinal cord injury, although there is still much work to do before we can engage in human clinical tests."
Acute spinal cord damage occurs during the first few weeks of the injury. In turn, the chronic period begins after a few months. It is anticipated that the stem cell treatment in humans will occur during spinal stabilization at the acute phase, when rods and ties are placed in the spinal column to restabilize it after injury. Currently, drug treatments are given during the acute phase to help stabilize the injury site, but they provide only a very mild benefit, and they do not foster regeneration of insulation tissue.
For the study, the UCI team used a novel technique they created to entice human embryonic stem cells to differentiate into early-stage oligodendrocyte cells. Oligodendrocytes are the building blocks of myelin, the biological insulation for nerve fibers that is critical for maintenance of electrical conduction in the central nervous system. When myelin is stripped away through disease or injury, sensory and motor deficiencies result and, in some cases, paralysis can occur.
The researchers injected these cells into rats that had experienced a partial injury to the spinal cord that impairs walking ability -- one group seven days after injury and another 10 months after injury. In both groups, the early-stage cells formed into full-grown oligodendrocyte cells and migrated to appropriate neuronal sites within the spinal cord.