Health & Medicine

Humans May Have Hidden Regenerative Powers, Scientists Discover

For generations, scientists viewed the inability to regrow lost body parts as a fundamental limitation of mammals. New research suggests that regenerative abilities may simply be switched off — not absent.

• Texas A&M researchers used a two-stage growth factor treatment to redirect the body's normal healing response away from scar formation and toward tissue regrowth.
• The treatment successfully restored bone, joints, ligaments, and tendons after amputation in animal models, using FGF2 and BMP2 growth factors applied in sequence.
• The approach rethinks regeneration not as a need for stem cells but as a redirection of existing fibroblasts toward blastema formation instead of scarring.

Why can a salamander regrow an entire limb while a human heals the same injury with nothing but scar tissue? This question has puzzled biologists since the time of Aristotle. New research from the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) suggests the answer may not be that humans lack regenerative ability — but that the ability is hidden within the body's normal healing machinery, waiting to be activated.

In a study published in Nature Communications, Dr. Ken Muneoka and colleagues describe a two-step treatment that enabled the regeneration of bone, joint structures, and ligaments in mammals. Although the regrown tissues were not perfect replicas of the originals, the approach could eventually reduce scarring and improve tissue repair after amputations.

The key insight is that mammalian healing is not a single path but a fork in the road. When mammals are injured, the body typically responds with fibrosis — fibroblast cells rush to close the wound and create scar tissue. This response prevents infection but limits the body's ability to rebuild what was lost. Animals capable of regeneration follow a different path: similar cells gather into a structure called a blastema, which serves as a foundation for new tissue growth.

"It's as if these cells can move in two different directions," Muneoka said. "They could either make a scar or make a blastema. Our research focused on redirecting the behavior of fibroblasts already present at the injury site."

The team developed a treatment using two well-known growth factors in sequence. The first step applies fibroblast growth factor 2 (FGF2) after the wound has already healed over. By waiting until the initial healing process is complete, the body responds normally before the intervention. FGF2 encourages the formation of a blastema-like structure — something that does not typically occur in mammals after this type of injury. Several days later, the researchers apply a second growth factor, bone morphogenetic protein 2 (BMP2), which prompts those cells to begin building new tissues.

"This is really a two-step process," Muneoka said. "You first shift the cells away from scarring, and then you provide the signals that tell them what to build."

The research also challenges the common assumption that regeneration requires stem cells. In many tissues, regeneration occurs because stem cells multiply and develop into new specialized cells. But in this study, the regenerated tissue came from fibroblasts already present at the injury site — cells that would normally create scar tissue. The treatment essentially reprogrammed their behavior rather than introducing new cell types.

The significance of this finding extends beyond the laboratory. If the two-step approach can be translated to human medicine, it could change how surgeons and doctors approach traumatic injuries, amputations, and severe tissue damage. Instead of accepting scarring as the inevitable outcome of healing, medicine could one day offer patients the option of true tissue regeneration.

Muneoka has spent his career studying this question. "Why some animals can regenerate and others, particularly humans, can't is a big question that has been asked since Aristotle," he said. "I've spent my career trying to understand that."