Scientists at Texas A&M University have demonstrated that mammals may possess a previously unknown capacity for limb regeneration. In a study published in Nature Communications, researchers successfully triggered partial regrowth of a lost toe in mice using two signaling proteins: fibroblast growth factor 2 (FGF2) and bone morphogenetic protein 2 (BMP2). Unlike typical wound healing that results in scarring, this method reprogrammed fibroblast cells to form a blastema—a temporary cluster of cells capable of regenerating tissue—similar to what is seen in salamanders and axolotls. The regrown tissue included bones, tendons, ligaments, and joint structures, though the new digits were sometimes misshapen or smaller than original ones.

The process works in two stages: FGF2 first shifts cells away from forming scar tissue, then BMP2 instructs the reprogrammed cells to build new structures. This approach bypasses the need for external stem cell transplants, instead leveraging cells already present in the body. Previous attempts without FGF2 failed to form blastemas or achieve full regrowth, highlighting the importance of the two-step signaling.

While still far from human application, the findings open new pathways in regenerative medicine. Both proteins are already under clinical evaluation—BMP2 is approved for reconstructive surgery, and FGF2 is progressing toward similar use—suggesting potential near-term benefits in improving wound healing and reducing scarring. The study challenges long-standing assumptions about mammalian healing limits and raises questions about how deeply conserved regenerative abilities might be across species.