Two-step treatment reveals hidden regeneration in mammals ^{CEFR B2}

For centuries mammals have lacked the ability to regrow lost limbs, a capacity retained by animals like salamanders. A study published in Nature Communications by researchers at Texas A&M University suggests that mammals may still harbour a hidden regenerative program that can be activated with the right signals.

Led by Ken Muneoka, the team devised a two-step treatment using two growth factors. They applied fibroblast growth factor 2 (FGF2) after the wound closed; this first signal stimulated formation of a blastema-like tissue, a structure normally seen in regenerative species but not in mammals. Several days later they applied bone morphogenetic protein 2 (BMP2). The second signal prompted those blastema-like cells to begin forming new anatomical structures.

The treatment restored many expected components removed during amputation — bone, joint structures, tendon, ligament and other connective tissues — producing organized skeletal and connective elements rather than perfect replicas. The work relied on multiple biological pathways and did not require adding external stem cells. As a result, researchers note the capacity was not absent but obscured. Because BMP2 already has some FDA approval and FGF2 is in clinical trials, the approach could move more quickly into clinical exploration, likely first to reduce scarring and improve tissue repair rather than immediately regrowing perfect limbs. The findings change how scientists view mammalian regeneration and raise new questions about how to activate these hidden healing abilities.