Paws and play: gene treatment helps rats with spinal cord injury regain their nerve

Rats with spinal cord injuries have regained the use of their paws after being given a groundbreaking gene therapy that helps to mend damaged nerves in the spine.

The new therapy works by dissolving the dense scar tissue that forms a thick barrier between severed nerves when the spinal column is broken.

Animals that were given the treatment produced an enzyme called chondroitinase which breaks down scar tissue and allows the broken nerves to reconnect with each other.

Tests showed that when the therapy was given for two months, rats relearned the kinds of skilled movements they needed to grab little sugar balls from a platform.

“The gene therapy has enabled us to treat large areas of the spinal cord with only one injection,” said Elizabeth Bradbury, who led the research at King’s College London. “This is important because the spinal cord is long and the pathology spreads down its whole length after injury.”

While more animal studies are needed before the therapy can go into human trials, researchers hope that ultimately the treatment will help people with spinal injuries who have lost the ability to perform daily tasks, such as using a knife and fork, picking up a mug, and writing.

“Recovering the use of the hands is the top priority for the majority of individuals living with spinal cord injuries. It would enable them to do everyday tasks such as washing and dressing independently, picking up a coffee cup, and would be life changing,” she added.

Writing in the journal, Brain, the scientists explain that the therapy could have a “significant impact” on people with tetraplegic paralysis, for whom regaining hand control could mean a major improvement in independence. Most human spine injuries, such as those inflicted by traffic accidents, damage the neck and so affect all four limbs.

Before it can be considered for human trials, the researchers will need to show that it works safely in larger animals which have suffered accidental injuries. They must also find a way to completely shut down the gene therapy once the spine has healed. At the moment, the scar-busting enzyme is still produced at low levels when the therapy is switched off.

“While we are hopeful, we know there is a long way to go to add further safety elements to the gene therapy before it can be used in humans,” said Bradbury.