Israeli Researchers Restore Mobility to Paralyzed Rats
November 13, 2017
A research group led by researchers from the Technion-Israel Institute of Technology has successfully repaired completely severed spinal cords in paralyzed rats, giving them the ability to walk again. An article on the subject was recently published in Frontiers in Neuroscience.
The dramatic success is the result of a collaboration between two experts from the world of biomedical engineering and stem cells: Prof. Shulamit Levenberg, Dean of the Faculty of Biomedical Engineering at the Technion-Israel Institute of Technology, and Prof. Daniel Offen of the Sackler Faculty of Medicine and Sagol School of Neuroscience at Tel Aviv University. The lab research was led by doctoral students Erez Shor (Technion) and Javier Ganz (TAU).
Spinal cord injury (SCI) is a severe event that often leads to irreversible paralysis in critical areas of the body. This is due to damage to the axons and glial cells that support the neurons and that are responsible for communication between them. Despite significant developments in the world of rehabilitation and developments such as allograft nerve transplantation, cell therapy and implantation of engineered tissue, achieving substantial recovery following complete spinal cord transection remains an unmet challenge.
The present study combines several different technologies: specialized 3D scaffolds and a method for transplanting them in the spinal cord developed in Prof. Levenberg’s lab; use of stem cells derived from gum tissue cells isolated in Prof. Sandu Pitaru’s lab; and the protocol of differentiation of stem cells into cells that secrete proteins that stimulate the regeneration of neurons developed in Prof. Daniel Offen’s lab.
The results are impressive: within about three weeks, transplantation of a three-dimensional construct of engineered tissue restored the ability to walk, coordination and other motor skills in 42% of the rats. This is in comparison with 0% of the untreated rats in the control group.
“In the past, researchers have managed to rehabilitate a damaged spinal cord,” explains Prof. Levenberg. “But this is the first time that stem cell transplantation has significantly restored sensation to limbs, as well as complex motor abilities including fast walking, in just a few weeks.”
According to the standard measure of functional recovery (ranging from 0 to 21), the average score achieved among the treated rats was 9.7. Forty-two percent achieved a score greater than 17, suggesting regained motor control in a way that allows for coordinated gait, proper positioning of the foot, foot height above the ground, weight support, general stability and tail-paw coordination. In most of the treated rats there was also an improvement in sensory responses to external stimuli, due to the rehabilitation of the electrical signal pathways between the nerve cells.
Monitoring of the rehabilitation process revealed that the implantation led to the gradual reconstruction of the transected spinal cord, with regrowth of axons and neurons and inhibition of scar formation. The scaffold is essential for this process because it directs the direction of growth of the neurons and axons and provides the tissue with a proper balance between flexibility and stiffness. This scaffold degrades gradually and disappears around 60 days after transplantation.
The conclusions corroborate the research hypothesis that a specific combination of specialized scaffolds, stem cells derived from human gum tissue and appropriate growth factors will lead to the regeneration of the spinal cord where it was transected. Moreover, this process leads to rehabilitation of the individual’s motor abilities, including walking. The researchers note that follow-up studies are now required that will lead to the application of the integrated technology in human beings.
This study was supported by the J&J Shervington Foundation, the Israel Foundation for Spinal Cord Injury and the Israel Science Foundation.
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