Doctors at Keio University in Tokyo have succeeded in restoring mobility to monkeys crippled with spinal cord injuries, by transplanting neural stem cells obtained from the spinal cords of fetuses, Hideyuki Okano, the team leader, said Monday.
It was reportedly the first time in history that researchers have succeeded in restoring mobility to primates with spinal cord injuries.
Okano, a professor at the medical department of Keio University, said that while the injured spinal cords of the monkeys were not completely mended, the results of the group's experiments may have opened the door to curing injuries of this kind in humans.
The group extracted neural stem cells from dead fetuses, multiplied them in test tubes, and transplanted them into five marmosets that had lost mobility in their hands and feet because of spinal cord injuries, Okano said.
Although the ability of the monkeys to grip sticks was initially less than 10 percent that of healthy monkeys, eight weeks after the transplants this ability rose to nearly 50 percent, Okano said.
The group believes the animals recovered their mobility after the neural stem cells grew into nerve cells and connected neural circuits that had been cut off by the injuries. The group transplanted the stem cells after pinpointing when injury inflammation had died down and before the immobility symptoms became chronic.
The doctors said the success of the transplants was down to timing.
They knew from previous experiments on primates that transplanting the cells immediately after the injury was an unsuccessful strategy due to inflammation.