Researchers have developed a promising technique that may some day restore bladder function in people with paralysis. They have regenerated nerves involved in bladder control in rats with spinal cord injuries, making it possible for the animals to urinate normally again.
The loss of bladder function is one of the most serious problems afflicting people with severe spinal cord injury.
Their bladders are no longer able to work properly because motor signals from the brain stem where the command center for urination is located are disrupted. When the nerves are severely damaged, the brain is no longer able to tell the bladder to squeeze and relax in order to pass urine. So, many individuals who are paralyzed must be catheterized to let their urine drain out. Otherwise, the liquid waste collects in the bladder and backs up to the kidneys, which is fatal.
Researchers at Cleveland Clinic and Case Western Reserve University Medical School in Ohio restored urination in rats whose spinal cords were cut. Scientists regenerated nerves across the 5-mm gap, using a three-step process.
They bridged the gap with healthy nerves taken from around the animals’ ribs, so there was no tissue rejection. Next, they applied a chemical called fibroblast growth factor to help the nerve grafts integrate and align to tissue at the injury site and they then delivered an enzyme, called chondroitinase, to limit scarring, which blocks nerve regeneration.
Jerry Silver of Case Western says nerves sprouted from high up in the brain and grew several centimeters to the injury site. After three months, according to Silver, researchers began to see some bladder control. After six months, he says there was a major improvement in the rats’ ability to control urination.
“.. repaired to I would say around two-thirds back to normal. That is not perfect, but I would say is a remarkable improvement,” he said.
After six months, the bladder control didn’t improve further.
Silver points to a similar procedure by a Taiwanese surgeon that restored partial walking in a man who had been injured with a knife. The research was controversial, says Silver, because other scientists couldn’t replicate the results.
In his study, Silver says the procedure restored some partial limb movement.
“We really don’t see much in the way of walking in our animals. They can wiggle their joints but they really don’t walk. But the recovery of urination was far more interesting and remarkable than their ability to locomote,” he said.
But Silver believes in time, the difficult spinal cord surgery will be perfected to the point where walking can be restored in paralyzed individuals.
An article by Jerry Silver and colleagues on restoring bladder control in paralyzed rats is published in the Journal of Neuroscience.