Salamanders can regenerate whole limbs, even as adults. While this amphibian superpower might seem irrelevant to human health, investigating the underlying biology may impart vital lessons about how the healing process can be redirected from scarring to replacing lost tissue. For this reason, Alessandra Dall’Agnese, a graduate student in the laboratory of Pier Lorenzo Puri, MD, PhD, professor in the Development, Aging, and Regeneration Program, recently wrote a review, published in BioEssays, comparing healing in salamanders to that in mammals.
“If we can figure out the means by which injured salamander limbs turn on developmental programs, we may be able to use that knowledge to create treatments that help the human body heal itself,” said Puri.
The review describes the key difference between how salamanders and humans heal following a major injury to a limb. Salamanders heal the wound, then form a regenerative center of proliferative, stem-like cells. In contrast, a regenerative center only forms in humans if the injury affects the tip of a finger or toe distal to the nail bed—otherwise, wound healing is followed by scarring.
“The important thing we’ve learned from salamanders is that there’s not an inherent limit to how much of a limb can be regrown,” explained Dall’Agnese. “The fact that mammals can only regrow the tips of digits instead suggests that there may be some property of the nail bed that fosters regeneration.
“From research in salamanders and mice, we know some of the factors that have to be turned on or off to enable regeneration. But we need a more detailed picture before we can start to develop therapies.”
“The possibility that we could discover salamanders’ secret to regeneration is a good example of why we should study a wide range of organisms,” Puri commented. “If we only studied animals closely related to us, we wouldn’t learn how to help our bodies do things they can’t normally do.”
The review is available online here.