Salamanders are renowned for their regenerative capabilities, such as growing back entire limbs. We can’t pull off this biological trick, but new research highlights a previously unknown regenerative ability in humans—one held over from our evolutionary past.
Scientists at Duke Health found that molecules called microRNA, which are “more active in animals that are known for limb, fin or tail repair,” such as salamanders and zebrafish, regulate the process of cartilage repair, according to a press release.
In animals, as well as in humans, microRNAs are found in greater numbers in the ankles and top layers of cartilage, as opposed to in the knees and hips.
In the study, scientists were also able to determine that the “age” of cartilage — which refers to whether any “amino acid conversions” have occurred — found in the ankles is young, while “it’s middle-aged in the knee and old in the hips,” according to the press release.
These findings help explain why ankles injuries tend to be easier and quicker to recover from as compared to hip and knee injuries, and why ankles are less likely to become “severely arthritic.”
“We were excited to learn that the regulators of regeneration in the salamander limb appear to also be the controllers of joint tissue repair in the human limb,” said lead author Ming-Feng Hsueh. “We call it our ‘inner salamander’ capacity.”
“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,” added researcher and Duke Professor Virginia Byers Kraus.