Reduced scarring helps nerves grow through spinal injuries

Infusing a naturally occurring anti-scarring agent called decorin into the damaged spinal cords of rats suppresses key molecules that block nerve regeneration after spinal cord injury, said Baylor College of Medicine (BCM) researchers in a study published today in the European Journal of Neuroscience.

The researchers are the first to use decorin to suppress inflammation and scar formation in spinal cord injuries. “Scar tissue that develops at sites of injury stops the regeneration of connections in the adult central nervous system,” said Dr. Stephen Davies, lead author on the study and an assistant professor of neurosurgery and neurosciences at BCM. “Infusion of decorin into spinal cord injuries prevents the formation of proteoglycan rich scar tissue by suppressing inflammation.”

Misaligned scar tissue that forms at spinal cord injuries physically blocks nerve regeneration and contains molecules called chondroitin sulfate proteoglycans that inhibit nerve fiber growth. Decorin inhibits the action of pro – inflammatory molecules released in spinal cord injuries, called transforming growth factors, which are thought to promote the formation of scar tissue.

Researchers in the study infused decorin directly into the injury site in rats with a mini-pump system, which used silica cannulas 160 microns in diameter. Because the cannulas were so small, they did not contribute to the formation of scar tissue. Using a high-powered laser scanning microscope and protein chemistry to analyze tissue samples, Davies and co-workers were able to show that decorin infusion reduced inflammation, scar formation and the levels of some proteoglycans by 80-95 percent allowing nerve fibers (called axons) to grow across spinal cord injuries in just four days.

“We have found a promising new approach to control inflammation and scar formation, which will be an important part of future strategies to encourage axon regeneration and recovery after spinal cord injury,” Davies said.

The work was supported by TIRR (The Institute for Rehabilitation and Research) Foundation’s Mission Connect and conducted in collaboration with scientists at Integra LifeSciences Holdings Corporation, The Burnham Institute and GTC Biotherapeutics Inc, who together developed the genetically engineered form of human decorin for use in the study.