A complicated procedure for transplanting human stem cells into the spinal cord of patients with a fatal neurodegenerative disease may be done safely, new research shows. Although it’s unclear whether the stem cell treatment can actually slow down the progression of amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease, researchers are hopeful that one day the procedure could be used to develop a new life-saving therapy.
This is not the first time that stem cells — cells that can develop into many different cell types — have been injected into the spinal cord of patients. But in today’s study, published in the journal Neurology, researchers at three different clinical centers have injected increasing doses of stem cells in a controlled way — and have shown that patients can tolerate the procedure.
"We’re quite excited about it."
"We met our goal of proving that this is a way to safely provide this kind of therapy and now [it] can be tested in a larger trial to see if it will actually change the course of disease," says Jonathan Glass, one of the study authors and the leader of the Emory ALS Center at Emory University. "We’re quite excited about it."
ALS is a fatal disorder in which motor neurons degenerate, causing patients to incrementally lose their ability to breathe and swallow, eventually leading to their death. Only one medication, called Riluzole, can slow down the progression of ALS, but it can’t cure the disease. That’s why stem cells are so appealing for treating the disease — they may be able to make motor neurons in the spinal cord live longer. In one previous study, neural stem cells injected into the spinal cords of rats with ALS delayed the onset of the disease and extended the rats’ lifespan by 17 days. "There’s a certain sense that stem cell therapies might be a way to move forward in these otherwise untreatable disorders," says Glass.
But injecting stem cells in the spinal cord is extremely dangerous. The slightest error could leave patients paralyzed and post-surgery complications can lead to death. That’s why today’s study focused on refining the injection procedure and assessing its safety. The fact that it was conducted at three clinical centers mean that it’s teachable, and could be performed widely in the future. "Here all it takes is one error and you leave someone paralyzed from the neck down," says Jeffrey Rothstein, a professor of neurology at Johns Hopkins School of Medicine, who wasn’t involved in the study. "Those safety errors can be very big."
"All it takes is one error and you leave someone paralyzed."
The researchers injected the cells into the spinal cords of 15 people with ALS. The patients received between 2 million and 16 million stem cells in 10 to 40 injections, in either one or two surgeries. Two patients had serious complications, including spinal cord swelling and severe pain. Others developed side effects to the immunosuppressant medications given so that the bodies wouldn’t reject the transplanted cells. But overall the procedure was found to be safe.
"It’s an important step," says Lucie Bruijn, chief scientist at the ALS Association, who did not take part in the study. (Some of the study authors, however, receive funding from the ALS Association.) "Every time we do something and these people have sacrificed and taken the risk, we learn something. And in this case, what is important was to be able to increase the dosing because we don’t know what dosing is going to be the correct one, and to know that it was safe to put it both in the lumbar and the cervical region."
"It’s an important step."
The study cautions that the procedure was only tried on 15 patients — an incredibly small number. Most studies testing drugs for ALS and other chronic neurological diseases require from 800 to 1,200 patients, says Rothstein. The small number of patients also didn’t allow the researchers to assess whether the stem cells were effective in slowing the disease. The study did not have a control group, so the researchers used three historical control groups from previous studies to see whether the treatment affected the disease at all. No changes in how ALS progressed were found. "The trial wasn’t designed, and really wasn’t powered, to test whether it was effective," Glass says.
However dangerous, the procedure needs to be tested further, because ALS patients are in dire need of new therapies, experts say. "ALS remains a progressive fatal disease," Holli Horak, an associate professor of neurology at University of Arizona, who did not take part in the study, wrote in an email, "so it is important to continue to explore novel treatments and therapeutics with the hope of providing relief or even a cure."