For a long time, scientists thought people cannot grow back lost body parts. Animals like salamanders can regrow whole limbs, but humans usually heal with scar tissue.
New work from Texas A&M’s College of Veterinary Medicine shows that mammals might have hidden healing powers. These powers sit inside the normal wound‑healing process and can be turned on under the right conditions.
Dr. Ken Muneoka, a professor of veterinary physiology, says the question of why some animals regenerate while humans do not has been asked since Aristotle. His team tried a two‑step method that let bone, joint and ligament tissues grow back after an amputation.
Turning Healing Toward Growth, Not Scars
When a mammal is hurt, fibroblast cells quickly close the wound and make scar tissue. This protects against infection but blocks true regeneration.
Regenerating animals take a different route. In salamanders, similar cells gather into a blastema, a starter kit for new tissue.
Muneoka explains that fibroblasts can go two ways: they can make a scar or a blastema. The researchers tried to push them toward the blastema path.
The Two‑Step Treatment
First, the team waited until the wound was closed, then applied fibroblast growth factor 2 (FGF2). This step encouraged cells to form a blastema‑like structure.
Days later, they added bone morphogenetic protein 2 (BMP2). BMP2 told the cells to start building bone, tendon and ligament tissue.
“You first shift the cells away from scarring, then you give them the instructions to build,” Muneoka says.
No Need for Extra Stem Cells
A key surprise was that the method did not require putting new stem cells into the body. The needed cells were already there; they just needed the right signals.
Dr. Larry Suva adds that cells once thought “unprogrammable” can actually be re‑programmed. The ability is not gone, just hidden.
What Was Regrown?
The scientists restored the main parts lost in the amputation: bone, tendon, ligament and joint tissue. The new structures were not perfect copies, but they resembled natural anatomy.
This shows that several biological pathways must work together for true regeneration.
Future Benefits
Even if full organ regrowth is far off, the approach could improve everyday wound healing. Reducing scar tissue and boosting repair could help many patients.
Both BMP2 and FGF2 are already approved or in clinical trials, which may speed up future testing.
Rethinking Mammal Healing
The study suggests mammals keep a dormant regeneration system. Turning it on could change how doctors treat injuries.
“Showing regeneration can be activated opens many new questions,” Suva says.