By eliminating an enzyme critical to cell growth, the scientists found a way to jump start the growth of nerve cells in mice.
In a collaborative effort by the University of California Irvine, University of California San Diego, and Harvard University, the researchers kind of turned back the hands of time. By manipulating the signaling pathway involved in cell growth, the researchers knocked out an enzyme called PTEN, which usually stops new nerve growth.
Without the enzyme, the mice with spinal cord damage were able to regrow cells.
Normally, nerve cells can't generally grow as we get older. Therefore, when the spinal cord is injured, it cannot regrow on its own. The researchers basically made the mice revert back to a time when PTEN activity is low (seen early on in development). Without this enzyme, the nerve cells could grow.
The study builds off of a 2008 Harvard Medical one that blocked the PTEN enzyme. Like this one, it showed similar regrowth in the nerve connections between the eye and brain in mice with optic nerve damage.
“Until now, such robust nerve regeneration has been impossible in the spinal cord,” Irvine researcher Oswald Steward said in a statement. “Paralysis and loss of function from spinal cord injury has been considered untreatable, but our discovery points the way toward a potential therapy to induce regeneration of nerve connections following spinal cord injury in people.
Now the researchers need to see if spinal cord function can be restored this way too.
But the real test will be to see if this can be used to treat spinal cord injuries in humans. Nearly 2 percent of the U.S. population suffer from paralysis — one million of them are paralyzed from a spinal cord injury.
“These devastating consequences occur even though the spinal cord below the level of injury is intact,” Steward added in a statement. “All these lost functions could be restored if we could find a way to regenerate the connections that were damaged.”