For generations the axolotl has aroused the curiosity of science due to its extraordinary capacity to regenerate entire limbs after an injury. This animal, endemic to Mexico and endowed with an almost mythical appearance, is the subject of some of the most innovative discoveries in regenerative biology. The fascination with its ability to recover arms, hands, or even organs like the heart and spinal cord, has been promoting research for years which are now beginning to provide concrete explanations.
Several studies published in scientific journals have revealed, in great detail, How the axolotl "knows" exactly which body part to rebuildThese findings, based on experiments with genetically modified specimens, They open the door to better understanding the mysteries of nature and design future therapies that could change human medicine forever.
The molecular secret: retinoic acid, enzymes and genes involved
The key to the process is in a small molecule called retinoic acid, derived from vitamin A and present in both axolotls and humans. This substance, widely used in skin and acne treatments, acts as a kind of navigation system for cells in the wound area, indicating with millimetric precision what tissue should be formed. Scientists have discovered that the amount of retinoic acid It is what “informs” whether it is time to regenerate a finger, a hand or an entire arm.
The mechanism is even more sophisticated, since It is not only retinoic acid that is involved. An enzyme called CYP26B1, responsible for degrading this compound, modulates its concentration along the limb. Near the body, retinoic acid levels are higher, and in remote areas, such as the fingers, they diminish. When this enzyme is artificially inhibited, axolotls can develop disproportionate limbs, even duplicating body parts whose reconstruction was not necessary.
Along with these elements, researchers have identified a specific gene called SHOX, which is also present in humans and regulates the growth of long bones during regeneration. Alter the function of SHOX can produce limbs abnormally short, demonstrating that this “genetic switch” is fundamental in axolotls and in our species.
How do the axolotl's cells achieve this feat?
When the axolotl suffers the loss of a limb, a wound forms at the site of the injury. cellular structure called blastemaThis grouping of cells, similar to embryonic cells, contains the potential to become any type of tissue: bone, muscle, skin or nerves. The most amazing thing is that, thanks to the "gradient" of retinoic acid, These cells can "remember" the exact position of the amputation and only regenerate what is missing.
To understand this process, scientists have worked with Genetically modified axolotls that glow fluorescently when their cells respond to retinoic acid. This confirms that the molecule guides the blastema cells and that the enzyme CYP26B1 ensures that the process stops when the member is complete.
It is curious that, although mammals and humans have the same genes and molecules, Our body responds to major injuries by forming scars instead of new members. This contrast, according to experts, lies in the way our cells interpret chemical signals after an injury.
Implications for human medicine: Are we close to regenerating limbs?
The parallel between the axolotl and humans fuels the hope that if we can reactivate these mechanisms, We could one day regenerate lost arms or legsSome human infants already show the ability to recover fingertips after injury, suggesting that the potential for regeneration exists, even if it is asleep in adulthood.
Currently, research is focused on discovering how activate that genetic memory y reprogram human cells to stop scarring and allow for complete regeneration. Techniques such as CRISPR gene editing and advanced cell therapies are the main bets for advancing regenerative medicine.
These discoveries in axolotls not only open up the possibility of curing serious injuries or degenerative diseases in humans, but also help to better understand the shared biological codeIf science can unravel the secrets of regeneration in these animals, the possibility of recovering a lost limb could be ever closer.
