A half-dozen paraplegic rats recovered movement in all lower joints after being transplanted with Neuralstem’s NSI-566 spinal cord stem cells—a result the company said could aid in treating human spinal cord injury.
The six were among 12 rats experiencing lower-body paralysis after undergoing complete spinal transections. The six were assessed over seven weeks and compared to a control group that had not received transplants. Neuralstem published results of its spinal cord stem cell transplant in the journal Cell, in a paper titled “Long-Distance Growth and Connectivity of Neural Stem Cells After Severe Spinal Cord Injury: Cell-Intrinsic Mechanisms Overcome Spinal Inhibition.”
According to the study, rats treated with NSI-566 showed significant locomotor recovery, with most (57%) of the grafted cells turned into neurons. Also significant, according to the company, was the number of axons that emerged, extending over 17 spinal segments both above and below the point of spinal cord lesion. The axons expressed synaptic proteins in the host gray matter, suggesting they made synaptic contact with host spinal neurons.
“The fact that these cells induce regeneration of axons and partial recovery of motor function makes them relevant for testing for the treatment of human spinal cord injury,” Karl Johe, Ph.D., Neuralstem’s chairman and CSO, said in a statement.
According to the paper, retransecting the spinal cord immediately above the graft abolished functional gain, a finding that Neuralstem said indicated that the regeneration of host axons into the human stem cell graft was responsible for the functional recovery.
Neuralstem has submitted an application to the FDA for a trial to treat chronic spinal cord injury with NSI-566. The cells were used in a recently completed Phase I clinical trial for amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease).