SAN FRANCISCO, Sept. 22 (UPI) -- Mice with spinal cord injuries had increased bladder control and reduced neuropathic pain after receiving injections of human stem cells, according to researchers.
The successful treatment of spinal cord injury side effects using stem cells is a significant step forward, and suggests two of the worst side effects of the injuries can be corrected, researchers at the University of California San Francisco report.
While a lot of research time has been spent working to get spinal injury patients walking again, the researchers say surveys and studies have shown patients find their lack of bladder control and neuropathic pain to be the worst part of post-injury life.
"This is a very important step," Dr. Arnold Kriegstein, a professor of developmental and stem cell biology at the University of California San Francisco, said in a press release. 'It shows efficacy of a human cell therapy for neuropathic pain and bladder dysfunction in an animal model of spinal cord injury. The next step on the way to the clinic and a trial in patients is scaling up production of the interneuron precursors facilities that meet FDA quality and safety standards."
In spinal cord injuries, chronic pain and loss of bladder control are caused by inflammation immediately after the injury, which leads to further damage of neural circuitry in the spinal cord causing it to lose control of pain and other sensations.
For the study, published in the journal Cell Stem Cell, the researchers caused lab-grown human embryonic stem cells to differentiate into medial ganglionic eminence-like inhibitory neuron precursors -- these are the cells in the spinal cord controlling sensations and other processes -- and transplanted them into mice two weeks after spinal injury.
Six months later, the stem cells had developed into mature neurons making the proper synaptic connections in mice that received transplants. While mice that did not receive transplants continued to be hypersensitive to touch and painful stimuli, those given transplants had fewer signs of neuropathic pain and improved bladder function.
"This is an important proof of principle for using cell therapy to repair damaged neural tissue. It brings us one step closer to using such transplants to bring much needed relief to people with spinal cord injuries," Kriegstein said.