Researchers in London and Amsterdam say a new gene therapy — one that can be activated and de-activated — successfully restored “hand” function in rats with spinal cord injuries.
Researchers at King’s College London and the Netherlands Institute for Neuroscience targeted the scar tissue that forms after a traumatic spinal injury. That scar tissue “prevents new connections being made between nerve cells,” researchers said in a June 14 news announcement.
The gene therapy being studied “causes cells to produce an enzyme called chondroitinase, which can break down the scar tissue and allow networks of nerve cells to regenerate.”
Professor Elizabeth Bradbury, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), said of the study, “What is exciting about our approach is that we can precisely control how long the therapy is delivered by using a gene ‘switch’. This means we can hone in on the optimal amount of time needed for recovery. Gene therapy provides a way of treating large areas of the spinal cord with only one injection, and with the switch we can now turn the gene off when it is no longer needed.”
Dr. Emily Burnside, another IoPPN researchers, noted that rats and humans perform similar series of movements when reaching for and grabbing objects, a fact that makes rats valuable to such studies. “We found that when the gene therapy was switched on for two months, the rats were able to accurately reach and grasp sugar pellets,” Burnside said. “We also found a dramatic increase in activity in the spinal cord of the rats, suggesting that new connections had been made in the networks of nerve cells.”
Researchers discovered that the rats’ immune systems were able to locate and remove the “gene switch” used to start and stop the gene therapy. One of the researchers’ additional tasks was to overcome that obstacle, which they accomplished by adding “a ‘stealth gene,’ which hides the gene switch from the immune system.”
Because researchers found that a small amount of the gene therapy remained active even after the gene was “switched off,” they’re now working on creating a way to completely stop the gene therapy when it’s no longer needed. Once that issue is addressed, researchers plan to go ahead with trials using larger species of subjects.
The study has been published in the journal Brain.
