Through the research they found that a blood clot almost immediately develops where the gecko lost its tail, sealing the wound. But if the research team covered the wound with gecko skin, before it could clot, the regeneration would fail to take place. This meant that the open wound itself is sending out signals to the body that something needs replacing.
When humans suffer an injury to their spinal cord (12,000 cases per year in the U.S.), scar tissue grows around the injury. The scar tissue seals the wound, minimizing inflammation, but also preventing regeneration much like the skin placed on the tailless geckos. According to Vickaryous, geckos don’t form that scar: “This absence of a scar is a big feature, we think, that permits them to regrow.”
This leads him to think scar tissue might be part of the reason why humans cannot heal from spinal injuries. “This may play a role in why we have a limited ability to repair our spinal cords. We are missing the key cells types required,” Vickaryous said. Radial glial cells, though abundant in the brain and spinal cord of human fetuses, are absent once a human reaches adulthood. Vickaryous thinks the fact we are missing these stem cells is the primary reason why we cannot regenerate spinal cords.
“Humans are notoriously bad at dealing with spinal cord injuries so I’m hoping we can use what we learn from geckos to coax human spinal cord injuries into repairing themselves,” says Vickaryous. He and his team now ponder whether reintroducing radial glial stem cells to a spinal cord injury could prevent the formation of scar tissue, and thus allow for regeneration.
Their research with leopard geckos continues, as they look to how other areas of their bodies regenerate, including brain cells. One day their research may unlock the secrets of human regeneration, minus the sensationalized blood-thirsty reptilian side effect.
To learn more about gecko regeneration, visit the Vickaryous Lab.