Breakthrough by Hong Kong researchers offers hope people with spinal cord injuries may walk again

HKUST researchers discover way to regenerate damaged spinal cords of lab mice, offering hope to millions of people with long-term injuries

PUBLISHED : Wednesday, 22 July, 2015, 3:01pm
UPDATED : Thursday, 23 July, 2015, 3:20am

Millions of people around the world paralysed by spinal cord injuries may one day be able to walk again, following a breakthrough by Hong Kong scientists.

Researchers at Hong Kong University of Science and Technology led by Professor Kai Liu have discovered a way to regenerate axons, or nerve fibres, in the spinal cords of mice with long-term injuries.

It's the first time axon regeneration has been induced in the corticospinal tract from injuries at least 12 months old.

"Considering animal life span is two to three years, roughly one year at this stage is comparable to 25 years in a human, so this means it's possible to be applied [to very old injuries]," Liu said.

By removing a gene called PTEN from laboratory mice with chronic spinal injuries, another gene, mTOR, was activated and drove damaged axons to regenerate and re-form connections.

"You can consider the spinal cord is like a highway," Liu said. "So the highway is a bilateral flow, [signals] both going up and down. But once your spinal cord gets disrupted, this information flow gets disrupted [and] both motor and sensory function are gone."

Liu said neurons inside the brain don't die, however, meaning that if a way could be found to restore the spinal cord connection, function could be restored.

In the United States alone there are an estimated 1,275,000 people living with paralysis as a result of long-term spinal cord injury.

Previous studies had shown if the PTEN gene was removed prior to injury or immediately afterwards, axon regeneration occurred, but Liu said his study was the first to show recovery in long-term corticospinal injuries.

Despite the promising results, Liu said more work had to be done before he would consider human trials. And while there was a possibility of using drugs to target genes, this could have consequences "because PTEN is a tumour suppressor, it is not logically a so-called druggable target."

Although no test subjects had regained function from the regeneration yet, Liu said it was the ultimate goal of his research.

"This will give a lot of hope to chronic [injury] people because most of the experiments or purely lab research target acute injury," he said. "Regeneration is a rare and difficult phenomenon, only in special cases [and] this is one of the few."

Liu and his team's research was published earlier this month in the Journal of Neuroscience.