If we know that the axolotl and the lizard are capable of regrowing some of their amputated limbs, we were unaware until now that in mammals too, this feat was not entirely impossible. Generally, for humans as for cats or mice, an injury then leaves room for a healing process. However, a team of researchers from Texas A&M University has just shaken up this biological certainty with a revolutionary experiment.
The secret lies in the behavior of our own cells. When we get injured, cells called fibroblasts rush in to patch the hole. An effective process for stopping hemorrhage, but which results in the creation of a scar preventing any regrowth. Scientists have discovered that by sending the right signals to these same cells, we can divert them from their clogging mission to transform them into real masons, generating new tissues.
In this study reported by the journal Science Alert, researchers succeeded in regrowing amputated fingers in mice. To do this, they looked at two specific proteins. The first, called FGF2, plays the role of programmer: it prepares the ground by forming a blastema, that is to say a bud of cells ready to rebuild everything. According to biologist Ken Muneoka, who led the work, “It’s really a two-step process. You start by moving the cells away from healing, and then you provide the signals that tell them what to build.”
The second phase is triggered by the BMP2 protein. It is she who gives the order to start the structural work such as bones, tendons, ligaments or joints. What is particularly exciting is that the researchers did not need to inject foreign stem cells. All the necessary cells were already there, on site, you just had to know how to talk to them. The results show complex bone and joint structures reforming where previously only a scar would have formed.
A feat adaptable to man?
Of course, the result is not yet perfect. The regenerated fingers in the mice were sometimes a little smaller than the originals, or slightly malformed. But the main thing is elsewhere because it has been proven that the regeneration machinery is not absent in us, just dormant. Larry Suva, co-author of the study, explains that this discovery is a radical game changer: “Once you show that regeneration can be activated, it opens the door to entirely new questions.”
For the general public, the question is obviously whether – and when – we will be able to benefit from this care. Although human tests are still a long way off, there is optimism: the proteins used, notably BMP2, are already known and used in certain types of reconstructive surgeries. This means that the path to clinical trials could be shorter than imagined, if only to improve the healing of complex wounds without going through the troublesome healing phase.
The issue goes well beyond simple aesthetic considerations. For thousands of amputees or people suffering from serious joint injuries, this path offers concrete hope. Imagine a future where, instead of mechanical prosthetics, the growth of new cartilage or bone fragment could simply be stimulated.
As Ken Muneoka points out, this study addresses an old problem: “Why some animals can regenerate and others, especially humans, cannot, is a big question asked since Aristotle. I’ve spent my career trying to understand that.” Today, it seems we’ve finally found part of the answer.
