In the near future, surgeons might be able to repair injured human nerves.
Penn researchers have found a way to grow transplantable nerve tissues which fix damaged nerves and help regeneration in animals.
Led by Neurosurgery professor and director of the Penn's Center for Brain Injury and Repair Douglas Smith, the study and the results were published in the journal Tissue Engineering earlier this month.
"We have created a three-dimensional neural network, a living conduit in culture, which can be transplanted en masse to an injury site," said Smith in a press release.
There are about 300,000 people in the United States with peripheral nerve injuries every year, according to D. Kacy Cullen, a post-doctoral fellow in Smith's lab.
"But there are insufficient means to repair the major injuries," he said. "There's a need."
Cullen said this study is one of the applications of Smith's paper on stretch growth of axons, or parts of nerve cells, which came out about 10 years ago.
The study consisted of two steps.
First, the team grew constructs of living and aligned track of axons by using the stretch growth method that Smith found.
Then they transplanted the constructs to bridge a portion of excised peripheral nerves in a rat by encapsulating the axons with protein and inserting them into a surgical tube.
Cullen explained that the team found the rat nerve regenerated using living constructs as a scaffold.
"So it was remarkable that the host nerve grew right along the axons we transplanted," Cullen said.
The team also observed that the living nerves they transplanted survived up to four months, which challenges the conventional wisdom regarding immune tolerance in the peripheral nerve system.
"It's very early, but it has potential down the road to be a useful tool to facilitate nerve generation where might not have been possible before," said Cullen.
In a press release, he added that "it's a race against time - if nerve regeneration happens too slowly, as may be the case for major injuries, the support cells in the extremities can degenerate, blunting complete repair."
Cullen added that many other steps are necessary before human clinical research can be conducted.
"It's far way from human application yet," he said. "But we are learning more about mechanisms in the human nerve system."
The National Institutes of Neurological Disorders and Stroke and the Sharpe Trust funded the study.
