Can we regenerate like Doctor Who—or at least a salamander?

Doctor Who may have an assist from really bizarre DNA that morphs you into a different form when you burn out, but you don’t have to be a Gallifreyan Time Lord to regenerate in some way.

Regeneration was once thought to belong either in science fiction or at least to animals like the axolotl, a salamander that can almost paranormally grow back lost body parts. It can even grow back parts of its brain (useful in a zombie apocalypse). Now new research suggests that humans have a regenerative ability when it comes to cartilage. We obviously can’t regrow entire limbs. What we can do, though, is still something that science used to think was impossible.

What a research team from Duke University School of Medicine (DUSM) recently found out was that humans can regrow cartilage much as salamanders do, which is a breakthrough even though we don’t have the capacity to give ourselves spare limbs. Yet.

“We believe that an understanding of this ‘salamander-like’ regenerative capacity in humans, and the critically missing components of this regulatory circuit, could provide the foundation for new approaches to repair joint tissues and possibly whole human limbs,” said coauthor and DUSM professor Virginia Kraus, whose findings were recently published in the journal Science Advances.

Human cartilage regeneration could be a miracle breakthrough to reverse the cartilage breakdown that causes osteoarthritis. The team discovered a built-in cartilage repair system that is strongest in the ankle joints and is still present, but weaker, further up the legs. The ages of the proteins were determined through amino acids, whose tendency to change from one form to another is predictable. The older the protein, the more amino acid conversions it has gone through.

This is very similar to the chance an animal like an axlotl will have of regenerating limbs, depending where it may be bitten by a predator—further extremities have a better chance. What the researchers determined we share with salamanders and other animals, which can regenerate limbs, fins, tails, and other body parts, are microRNA molecules. microRNA is left over from evolution and is the superpower behind cartilage regeneration.

Just as in animals, more microRNA activity was found in our furthest extremities. Turning microRNAs into medications could mean an eventual stop or even reversal to osteoarthritis. That’s not all. While we can’t regenerate limbs on our own, this science could someday be manipulated to actually grow them back.

“We believe we could boost these regulators to fully regenerate degenerated cartilage of an arthritic joint. If we can figure out what regulators we are missing compared with salamanders, we might even be able to add the missing components back and develop a way someday to regenerate part or all of an injured human limb,” Kraus said. “We believe this is a fundamental mechanism of repair that could be applied to many tissues, not just cartilage."

Humans may not be part salamander, but in a world where we’re already figuring out how to merge our genes with other species, it wouldn’t be surprising if we can eventually regenerate like one.

(via Duke University School of Medicine)