Cleveland researchers use experimental nerve 'bridge' to restore breathing in rats with spinal cord injuries (video)

Published: Wednesday, July 13, 2011, 1:00 PM Updated: Wednesday, July 13, 2011, 3:29 PM
By John Mangels, The Plain Dealer The Plain Dealer

CLEVELAND, Ohio -- Using tools familiar to any gardener -- a chemical fertilizer and a sort of high-tech trellis -- Cleveland researchers have coaxed skittish nerve fibers to bridge a gap in rats' damaged spinal cords and forge new connections.

The repairs, though experimental, revived the rats' partially paralyzed diaphragm muscles, restoring normal or near-normal breathing in nine of 11 test animals, the Case Western Reserve University scientists report Thursday in the journal Nature.

"It's pretty amazing," said CWRU neuroscientist Jerry Silver, who led the research project and described it as the culmination of 30 years of effort. "Our work is one of the most convincing demonstrations [to date] of the return of robust function" after paralysis.

The CWRU approach blends two nerve-regrowth methods, leveraging the power of each.

"The experiments are significant in demonstrating that this combination of two repair strategies can work together to enhance recovery in the complex circuitry that controls breathing," spinal cord injury researcher James Fawcett, who heads Britain's Cambridge Centre for Brain Repair at the University of Cambridge, said via email. "This paper from the Silver laboratory shows that a combination treatment can be very successful." Fawcett was not involved in the CWRU project.

Researchers have tried many techniques over the years to overcome the devastation of spinal cord injuries, which affect 12,000 Americans annually. Progress has been slow, a testament to the human nervous system's complexity.

Much of that experimental work has focused on re-establishing the ability to walk, a goal that remains unmet. Silver's lab has concentrated instead on the challenges of regaining breathing and bladder control. "Our goal was to target one critical muscle that [paralyzed] people would like back," he said.

Those two bodily functions are far less complicated than walking in terms of making neurological fixes. The shortest stroll requires a suite of highly coordinated limb and trunk movements involving dozens of muscles; by contrast, breathing and urination basically involve flexing only the diaphragm or the sphincter. Restoring them could boost paralyzed patients' long-term survival and dramatically improve their day-to-day lives.