Axolotls May Hold the Key to Regrowing Limbs
16 comments
·June 19, 2025neom
Here is the paper: https://www.nature.com/articles/s41467-025-59497-5
leidenfrost
I wonder how much stress growing a whole limb imply on the body.
Would it male you prone to get cancer, since all that replication "depleted" our stem cells and brown fat reserves? What about our telomeres?
oa335
Biologist Michael Levin posits that bio-electric fields “, not simply genes, hold the key to limb regeneration.
bilsbie
Do we know how a human would regrow a limb? Would it start out as a small limb and grow out or just grow arm first then elbow, forearm, etc.
alphazard
We do grow limbs routinely, in utero. Typically 4 limbs per person. I would assume that we would be looking to activate the genes responsible for that same process. You can look up timelapse videos of embryos on youtube to answer your question.
It seems more likely for there to be a single set of genes responsible for growing a limb than 2 sets in the Axolotl. Especially since the new limbs seem identical to the old ones, rather than following a distinct backup blueprint.
sheepscreek
From what I’ve read, Salamanders of all kind retain their stem-cell embryonic growth capabilities in their early life (after birth). But once they become adults, they become more mortal like the rest of us. But Axolotls for some reason never lose their ability.
crazydoggers
An axolotl is a salamander that remains in its larval form throughout its life, while most salamanders go through a metamorphosis during sexual maturity, so it’s not surprising it retains embryonic growth capabilities.
There’s actually a theory that hominid ancestors at some point split off from other great apes by also not going through the typical great ape sexual maturity. For examples humans look a lot more like juvenile chimps that we do sexually mature chimps.
zabzonk
Why we can't do it: https://www.popsci.com/newts-toads-regrow-limbs-humans-evolu...
reliablereason
Seams reasonable that it would probably form in the same way that it forms in the embryo. But i guess it would depend on how we manage to convince the body to do this.
echelon
Introducing pluripotent cells seems like a recipe for disaster.
We should really just grow clones in labs and harvest them for parts.
Remove the brains at week 16 through genetic and surgical means. Keep the rest of the body artificially alive. Expensive upfront, but massively scaleable.
MHC, ABO, etc. complexes engineered to be transplant compatible.
We could replace organs and blood as we age. In fifty years, full head transplants could tackle every disease except brain and blood cancers and neurodegeneration. Every other disease solved.
It's so simple and obvious, but nobody can get over the egocentric morality qualms and superstitious ick factor.
Our bodies are plants. It's our minds that are special. We should be able to transplant every other part.
v3ss0n
Brain is necessary for growth , repair , and several immune responses. Do you want a zombie arm?
PaulHoule
Gets you a factor of two if you're lucky. Imagine the mental fidelity of presidents 46 and 47 when they're ready for a third full body transplant.
nickpeterson
What if we transplant just part of the brain?
IX-103
I think the big factor there is that you'd have to wait over a decade for the transplant to be the correct size. I'm also not sure that we have the technology to keep a brainless body alive for such a long period - the brain is involved in a large number of processes that we don't yet have a way to replicate. And then you'd need a complex surgery to perform the transplant.
Pluripotent cells work fine in many animals with no apparent problems and avoid all of the issues with the clone approach. If pluripotent cells turn out to cause problems, then we could always engineer a kill switch to make sure they die off after the limb is regrown.
metalman
ya, but no be riding the glitch train I have a atrong sense that the brain is very much involved in growing the rest of the nervous system......which the "parts" need to function these hypothetical procedures will be hugely complex surgeries that will take a long, realy long time, and there will be complications, so the risk to benifit ratio will only be good in a few scenarios....for which you need a wildly complex and expensive facility to prepare for many years in advance. gets worse, as the timing of procedures may require "parts" that are critical for the....."chasis" to self maintain, then requiring other back up "chasis" gets even worse, as the learning curve is going to be exceptionaly steep, and long, almost certainly meaning that who ever trys first, wont live long enough to benifit. all for what? a new chasis for a worn out brain?
> That helped them pinpoint a molecule called retinoic acid—a derivative of vitamin A found in many skincare products—as a key ingredient for limb regeneration
Hoo boy, I am seeing some serious fuel for snake oil, here.
I wonder how long before I start getting spam selling retinoic acid as an aid in growing ... er, a limb ...
Also, I wonder if the article was edited by AI. That may not be a bad thing, but it would be interesting if The Smithsonian is using AI editors.