April 27, 2001 (Toronto) -- A hot new area of scientific investigation revolves around using stem cells to repair damage done to certain parts of the body. Stem cells have the unique ability to transform themselves, after transplantation, into the types of cells or tissues in their new surroundings. The most adaptable of these stem cells come from fetuses, but using those is very controversial. New research suggests that one day we might not have to.
Results from a mouse study presented here at the 69th annual meeting of the American Association of Neurological Surgeons (AANS) suggests that transplanting adult stem cells from the brain into the spinal cord may someday prove an effective therapy for people suffering from spinal cord injury.
Researchers studied this approach in 15 adult female mice with moderately severe spinal cord injury. Eight of the mice received cell transplants taken from special regions in the brain, while the other seven got nothing.
For seven days after the transplantation, researchers kept track of the mice's movement and the function of their nervous system. The mice that received the transplanted cells were found to be more mobile, according to study co-author Charles Tator, MD, PhD, a neurosurgeon at Toronto Western Hospital.
Although their mobility improved slightly, Tator stresses that the mice were far from back to normal. "None of these mice could walk normally afterward," he says. "I wouldn't want to create the impression that we returned them to normal after one week."
However, Tator says, if the mice had been assessed for longer than one week, better results may have been seen.
Tator's research group also reported some positive findings about the cells themselves following transplantation.
"What we found was that these cells survived ... and formed new supporting cells in the spinal cord," he tells WebMD.
"The uniqueness of our work is that this was an adult brain cell, so it does away with the concern of using fetal cells," says Tator. Translating this mouse work into humans, he says, may mean removing stem cells from a deceased person, growing them in the laboratory, and then transplanting them into a person with either spinal cord injury or a potential host of other neurological conditions.
Animal-to-human cell transplants aren't completely ruled out, however. Just two weeks ago, on April 13, an Albany, N.Y., man received a transplant of pig cells into his spinal cord.
Charles Dederick underwent the experimental procedure -- the first of its kind, according to officials at Albany Medical Center Hospital -- in an attempt to restore function to his arms and legs after a motorcycle accident in 1997 rendered him quadriplegic. Although he has not noticed any improvement as yet, he remains hopeful.
Each year, approximately 8,000 Americans suffer traumatic spinal cord injury, with common causes ranging from car accidents, falls, and sports and recreational activities. In addition to paralysis, spinal cord injury can cause abnormal bladder and bowel function, loss of temperature control, and even death.
Findings such as those reported in Toronto " represent encouraging progress toward the development of a cure," says Robert F. Heary, MD, who attended the AANS meeting. "In the short term, these results have been excellent."
To confirm the potential, studies of longer duration are needed, says Heary, a neurosurgeon at the University of Medicine and Dentistry of New Jersey, at New Jersey Medical School in Newark. "But studies such as this, which lend promise for the future, are spectacular," he says.
Importantly, Tator says, the potential of applying this science in human is still years away. Overcoming things like infection and rejection as cells are transplanted from one human to another will be a big challenge, he says.
"Our future studies are going to involve following these mice for a longer period of time in a larger number of animals to see if they can recover more. We also have plans to perform spinal cord to spinal cord transplantation," he says. "The stem cells that originate in the spinal cord may be more effective in regeneration than brain cells for spinal cord injury."
Further laboratory tests of this strategy are necessary before clinical trials in humans can be considered, Tator says.