For the first time, people with broken spines have recovered feeling in previously paralysed areas after receiving injections of neural stem cells.
Three people with paralysis received injections of 20 million neural stem cells directly into the injured region of their spinal cord. The cells, acquired from donated fetal brain tissue, were injected between four and eight months after the injuries happened. The patients also received a temporary course of immunosuppressive drugs to limit rejection of the cells.
None of the three felt any sensation below their nipples before the treatment. Six months after therapy, two of them had sensations of touch and heat between their chest and belly button. The third patient has not seen any change.
"The fact we've seen responses to light touch, heat and electrical impulses so far down in two of the patients is very unexpected," says Stephen Huhn of StemCells, the company in Newark, California, developing and testing the treatment. "They're really close to normal in those areas now in their sensitivity," he adds.
"We are very intrigued to see that patients have gained considerable sensory function," says Armin Curt of Balgrist University Hospital in Zurich, Switzerland, where the patients were treated, and principal investigator in the trial.
The data are preliminary, but "these sensory changes suggest that the cells may be positively impacting recovery", says Curt, who presented the results today in London at the annual meeting of the International Spinal Cord Society.
The patients are the first three of 12 who will eventually receive the therapy. The remaining recipients will have less extensive paralysis.
"The sensory gains, first detected at three months post-transplant, have now persisted and evolved at six months after transplantation," says Huhn. "We clearly need to collect much more data to demonstrate efficacy, but our results so far provide a strong rationale to persevere with the clinical development of our stem cells for spinal injury," he says.
"We need to keep monitoring these patients to see if feeling continues to affect lower segments of their bodies," says Huhn. "These are results after only six months, and we will follow these patients for many years."
Huhn says that the company has "compelling data" from animal studies that the donated cells can repair nerves within broken spines.
There could be several reasons why the stem cells improve sensitivity, says Huhn. They might help to restore myelin insulation to damaged nerves, improving the communication of signals to and from the brain. Or they could be enhancing the function of existing nerves, replacing them entirely or reducing the inflammation that hampers repair.
Other researchers were intrigued but cautious. "It's work in progress," says Wagih El Masri, a spinal specialist at the Midlands Centre for Spinal Injuries in Oswestry, UK, who attended Curt's presentation. "We need larger numbers of patients treated to confirm whether this interesting finding has any future."
He says that about 3 per cent of patients show similar improvements spontaneously at about 6 months, but seldom beyond that. Testing the therapy on patients who were injured more than six months before would help to confirm that the stem cells are responsible for the results.