Limb Regeneration: Animals Do It. Why Can’t People?

If the axolotl loses a limb after injury, the salamander is able to regrow it. Someday, researchers hope, humans will be able to do this as well.

A recent study in PLOS One identified the genetic regulators that allow zebrafish, a ray-finned fish called the bichir, and the axolotl to regenerate after injury. The findings indicate that these mechanisms aren’t specific to particular species, but have been conserved through evolution.

“Nature and evolution have performed the perfect experiment for us. These organisms last last had a common ancestor over 420 million years ago. During that time, nature has fine-tuned the circuits that are really important for the process of limb regeneration,” Voot P. Yin of the MDI Biological Laboratory, told ALN exclusively.

The team of researchers specifically focused on blastemas. Formation of this mass of cells is the first step to regeneration.

“At a cellular level, all three of these organisms regenerate the same way. They form a a tissue called the blastema for wound healing that is maintained as an outgrowth through regeneration,” added Vin’s collaborator, fellow MDI Biological Laboratory scientist, Benjamin L. King, Ph.D. “We studied the genes that gave rise to the blastema in all three organisms. These appendages are obviously quite different–an axotl forelimb is different than a zebrafish fin. But, by comparing this similar tissue in all three organisms, we focused on that network of genes that are activated.”

This discovery could help speed wound healing, getting patients back on their feet more quickly. It could also result in the development of sophistocated prosthetics after amputation. “The genes that we found in these organisms, including the microRNAs, are conserved with humans. Obviously, we don’t have the same regenerative capacity as these other animals, but we do have the same genes. We hope to be able to find a way to reactivate the circuit in humans someday,” King concluded.