University of Pittsburgh reseachers studying nerve regeneration are seeing promising results in monkey test subjects. Kacey Marra, a professor of plastic surgery and faculty member of the McGowan Institute for Regenerative Medicine, hopes to try the method in humans soon.
The most common way to treat a long segment of nerve damage is essentially transplantation: a healthy nerve from the back of the leg is taken out, spliced into thirds, and bundled together to replace the damaged nerve. This can bring back about 40 percent of function.
Marra's study used a biodegradable tube that both serves as a guide for the nerve to regrow itself, and releases a protein called GDNF to simulate nerve regeneration. The protein enters the body over the course of three months, giving nerves, which grow about a millimeter per day, enough time to regenerate.
In Marra's study, monkeys were trained to pick up and eat pieces of food by pinching their forefinger and thumb. The researchers then intentionally damaged the nerve controlling the hand, and implanted the tube.
"Over time, as the nerve regenerated down the arm into that muscle, they regained function and sensation," she said.
The monkeys recouped about 80 percent of their hand function. Marra is hopeful that her lab's research will benefit the roughly 600,000 nerve repair patients in the U.S. every year.
"We have a large number of clinical applications we want to target, starting with diabetic [nerve damage] that affects so many people," Marra said.
FDA approval is required before this method can be tested in people. Marra's team founded a company, AxoMax, to patent the nerve guide in an effort to speed up the sometimes lengthy approval process. Marra is hoping the first human trials can start next year at UPMC.