A team of researchers from the University of California, San Diego School of Medicine and the Veterans Affairs San Diego Healthcare System, have been able to successfully regenerate lost tissue in damaged corticospinal tracts, using neurons derived from stem cells. This is extremely exciting news as, up until now, researchers have been unable to regenerate the corticospinal projection – the most important human motor system which runs from the cerebral cortex into the spinal cord – although many have tried.
The breakthrough came about when the team decided to use neural stem cells to determine whether they would support regeneration, by grafting neural progenitor cells onto the sites of spinal injuries in rats. Directed to grow as a spinal cord, these grafted stem cells successfully formed functional synapses that were able to improve the movement of the rats’ forelimbs. This was a particularly good result as it refuted the current belief that the neurons in the corticospinal projection were completely lacking the internal mechanisms necessary for regeneration.
Past Research and new research
While past research into this area has found some success in regaining functional recovery in rats, none of these studies have been able to regenerate the corticospinal axons. As humans use corticospinal axons for voluntary movement, without the regeneration of these axons, researchers believed that it was unlikely that any of these therapies had the potential to improve function in human patients. Now that they’ve found a way to regenerate this vitally important motor system, it’s given researchers renewed hope that beneficial therapies can be found.
However, finding suitable therapies is likely to be a long and drawn out process, as more work is needed before it can be tested on humans, both in regards to safety and long-term functional benefit. This means further testing to find ways to transfer the technology to both larger animal models and humans, and to identify the best type of human neural stem cells to give optimum results.
The team, who worked in conjunction with researchers in Japan and Wisconsin, have recently published their findings in the online journal Nature Medicine.