Researchers from the Perelman School of Medicine have devised a new paradigm for repairing nerve injuries that preserves muscle function and prevents degeneration. The technique, which involves an injectable microtissue containing motor and sensory neurons encased in protective tissue, or TE-NMIs, “babysits” regenerative pathways and muscle while nerves regrow. The findings are published in Bioactive Materials.
By injecting the TE-NMIs close to muscles, the technique protects neurons and increases the likelihood that a greater quantity of axons—the long “tail” of a neuron that serves to transmit nerve impulses to other neurons or to muscle—will connect with the muscle and maintain regenerative pathways.
Researchers tested the approach in rodents with a severed sciatic nerve, injecting them with either a TE-NMI or a microtissue without any neurons. In animals that received TE-NMIs, researchers were able to electrically stimulate the nerve stump being “babysat” by the TE-NMI and record a muscle response up to five months after the tissue was implanted. No muscle response was detected in the control group.
“There are hundreds of thousands of patients who undergo surgery to repair nerve injuries every year, and even if a surgeon performs a perfect procedure, they can’t make axons regrow faster than about one inch per month. For nerve injuries in the upper arm or upper leg, regeneration could take years; however, the pathway leading to the muscle and the muscle itself will irreparably degenerate after six to 12 months without connections from axons, resulting in permanent loss of motor and sensory function,” says senior author D. Kacy Cullen, an associate professor of neurosurgery. “By increasing the time window for a patient’s axons to reconnect to muscle, this research has potential to improve the extent of recovery for patients without causing further damage.”
This story is by Kelsey Odorczyk. Read more at Penn Medicine News.
