Salamanders can regrow limbs. Could humans someday? - Harvard Gazette

"Biologists long have been fascinated by the ability of salamanders to regrow entire limbs. Now Harvard researchers have solved part of the mystery of how they accomplish this feat - by activating stem cells throughout the body, not just at the injury site. In a new paper published in the journal Cell, researchers documented how this bodywide response in axolotl salamanders is triggered by the sympathetic nervous system, or the "fight or flight" network."

""We've shown the importance of the adrenaline stress signaling hormone in getting cells ready for regeneration," said Duygu Payzin-Dogru, lead author of the study and a postdoctoral researcher in the Department of Stem Cell and Regenerative Biology. "Because adrenaline exists in humans, this tells us we can co-opt some of the things we found in the axolotl to perhaps improve regenerative outcomes in humans. We have some of the same components and just have to figure out the right way to implement them.""

"Axolotls are often examined as model organisms of limb regeneration because they are among the fastest-breeding species of salamanders. Some invertebrates, such as planarian flatworms, can regrow entire bodies from small bits of tissue. But salamanders are the only vertebrates that can regenerate full limbs. When an appendage is severed, salamanders sprout a blastema - a lump that contains the precursor cells that become increasingly specialized to form a new arm, leg, or tail."

Axolotl salamanders activate stem cells throughout the body after limb loss instead of only at the injury site. The sympathetic nervous system triggers this bodywide activation through adrenaline stress signaling, which primes cells for regeneration. Adrenaline is present in humans, indicating that analogous components might be co-opted to improve human regenerative outcomes if implemented correctly. Salamanders form a blastema at amputation sites that contains precursor cells which progressively specialize into a new arm, leg, or tail. Some invertebrates can regrow entire bodies, while salamanders are the only vertebrates known to regenerate full limbs.

Read at Harvard Gazette