Researchers have pinpointed stem cells within the spinal cord that, if persuaded to differentiate into more healing cells and fewer scarring cells following an injury, may lead to a new, non-surgical treatment for debilitating spinal-cord injuries.
Injuries of the spinal cord resulting from trauma that fractures or dislocates vertebrae are usually characterized by broken pieces of vertebrae tearing into cord tissue or pressing on nerves. In the worst case, the cord can no longer relay messages below the point of injury and the victim is paralyzed.
The tiny number of stem cells in the adult spinal cord proliferate slowly or rarely, and fail to promote regeneration on their own. But recent experiments show that these same cells, grown in the lab and returned to the injury site, can restore some function in paralyzed rodents and primates.
As you are aware if you read this blog, in a developing embryo, stem cells differentiate into all the specialized tissues of the body. In adults, stem cells act as a repair system, replenishing specialized cells, but also maintaining the normal turnover of regenerative organs such as blood, skin or intestinal tissues.
In a new study, Konstantinos Meletis, a postdoctoral fellow at the Massachusetts Institute of Technology's Picower Institute, and colleagues at the Karolinska Institute in Sweden, have uncovered the molecular mechanism underlying the tantalizing results of the rodent and primate experiments. And they go one step further. By identifying for the first time where this subpopulation of cells is found, they pave a path toward manipulating them with drugs to boost their inborn ability to repair damaged nerve cells.
Specifically, they found that neural stem cells in the adult spinal cord are limited to a layer of cube- or column-shaped, cilia-covered cells called ependymal cells. These cells make up the thin membrane lining the inner-brain ventricles and the connecting central column of the spinal cord. "We have been able to genetically mark this neural stem cell population and then follow their behavior," Meletis said. "We find that these cells proliferate upon spinal cord injury, migrate toward the injury site and differentiate over several months."
Adapted from the MIT announcement.
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