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.
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鈥淭he fact we鈥檝e seen responses to light touch, heat and electrical impulses so far down in two of the patients is very unexpected,鈥� says Stephen Huhn of , the company in Newark, California, developing and testing the treatment. 鈥淭hey鈥檙e really close to normal in those areas now in their sensitivity,鈥� he adds.
鈥淲e are very intrigued to see that patients have gained considerable sensory function,鈥� says Armin Curt of Balgrist University Hospital in Zurich, Switzerland, where the patients were treated, and .
The data are preliminary, but 鈥渢hese sensory changes suggest that the cells may be positively impacting recovery鈥�, says Curt, who presented the results today in London at the of the International Spinal Cord Society.
Persistent gains
The patients are the first three of 12 who will eventually receive the therapy. The remaining recipients will have less extensive paralysis.
鈥淭he sensory gains, first detected at three months post-transplant, have now persisted and evolved at six months after transplantation,鈥� says Huhn. 鈥淲e 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,鈥� he says.
鈥淲e need to keep monitoring these patients to see if feeling continues to affect lower segments of their bodies,鈥� says Huhn. 鈥淭hese are results after only six months, and we will follow these patients for many years.鈥�
Huhn says that the company has 鈥渃ompelling data鈥� from animal studies that the donated cells can repair nerves within broken spines (Neurological Research, DOI: ).
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.
Abandoned trial
The announcement comes almost a year after the world鈥檚 only other trial to test stem cells for spinal injury was suspended. Geron of Menlo Park, California, had injected neural stem cells derived from embryonic stem cells into four people with spinal injuries when it announced that it was going to focus on cancer therapies instead. The company also abandoned its other stem-cell programmes combating diabetes, heart disease and arthritis.
Huhn hopes that the results from the StemCells trial will revive the enthusiasm that evaporated following Geron鈥檚 bombshell. 鈥淚t鈥檚 the first time we鈥檝e seen a signal of some beneficial effect, so we鈥檙e moving in the right direction, and towards a proof of concept,鈥� he says.
The news was welcomed by other pioneers of neural stem-cell research. 鈥淚t looks encouraging and has some parallels with what we鈥檝e seen in our trial in stroke patients,鈥� says Michael Hunt, CEO of ReNeuron, in Guildford, UK, which in 2010 became the first company in the world to treat strokes with stem cells.
鈥淭hey appear to be making progress, and that鈥檚 good for the stem-cell field generally, and for neural stem-cell research in particular,鈥� says Hunt. He says that seven people who have had strokes have now been treated, and that some have shown signs of functional improvement without adverse effects.
鈥淚t鈥檚 early days, and we are proceeding cautiously before hopefully moving to more substantive trials,鈥� says Hunt.
鈥淭hese initial data certainly indicate that stem-cell transplantation may help remediate some of the severe functional loss associated with spinal cord injury,鈥� says George Bittner of the University of Texas at Austin, who has developed a polymer-based system for rapid treatment of damaged nerves.
But, he says, a single mode of treatment is unlikely to be enough to restore function after spinal cord injuries. We will need 鈥渃ombinations of approaches including stem cells, polymer-based treatments, retraining and physical therapy鈥�.
Other researchers were intrigued but cautious. 鈥淚t鈥檚 work in progress,鈥� says Wagih El Masri, a spinal specialist at the Midlands Centre for Spinal Injuries in Oswestry, UK, who attended Curt鈥檚 presentation. 鈥淲e need larger numbers of patients treated to confirm whether this interesting finding has any future.鈥�
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.
