Like many lizards, geckos can escape from predators that grab their tails by breaking away and then regrowing the severed appendage. Further, they can complete that regrowth process in 30 days, which is speedier than any other type of lizard.
Now scientists at the University of Guelph in Canada have discovered that the gecko tail—which also includes part of its spinal cord—contains a specific type of stem cell that rapidly proliferates and churns out proteins in response to injury. These proteins generate a new spinal cord. They believe their discoveries, published in the Journal of Comparative Neurology, could be used to develop new treatments for spinal cord injuries in people.
The researchers discovered that the gecko’s tail houses a population of stem cells called radial glia, which are normally in a resting state. When an injury occurs, they jump into action and continue making healing proteins until the new spinal cord is completely built.
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The human body responds to a spinal cord injury in a completely different manner, making scar tissue to seal the wound. That sealing prevents regeneration.
"It's a quick fix but in the long term it's a problem," said Matthew Vickaryous, the lead author of the study, in a statement. "This may play a role in why we have a limited ability to repair our spinal cords. We are missing the key cell types required."
In the lab, Vickaryous simulated spinal cord injuries in geckos by pinching their tails. They measured what happened in individual cells in the tail before and after regeneration.
Stem cells have long been of interest to scientists and companies searching for new treatments for spinal cord injuries. Earlier this year, for example, Asterias Biotherapeutics published data from a small study of embryonic stem cells in five patients with spinal cord injuries, all of whom experienced an improvement in motor function, the company said. Switzerland-based G-Therapeutics is developing a device that uses electrical signals and gravity-assistance technology to restore movement in patients.
The spinal cord study in geckos is part of a larger effort to understand all of the regenerative properties of the lizard’s central nervous system. The next step for the University of Guelph research team will be to figure out how the gecko makes new brain cells.