Humans are like salamanders

Cartilage in human joints can repair itself, researchers claimed.

SALAMANDERS, here represented by a mascot, have a special ability to regenerate body parts with ease. AFP

The cartilage in human joints, especially in ankles but less so in hips, can regenerate following injuries, similar to salamanders which can regenerate limbs.

Researchers at Duke Health have published in the Science Advances a study which identified a mechanism for cartilage repair, a finding that could impact positively in the treatment of osteoarthritis, the most common joint disorder in the world.

“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 Duke professor Virginia Byers Kraus.

The discovery was based on Kraus and her team devising a way to determine the age of proteins through “internal molecular clocks” using amino acids whose conversion from one form to another can be predicted with regularity.

The premise was that newly created proteins contained few or no amino acid conversions while older proteins have a lot. With this, researchers were able to use sensitive mass spectrometry to identify the age of key proteins in human cartilage.

The correlation between the age of human cartilage and its location aligned itself with how some animals regenerate body parts like the salamander and zebrafish.

The regeneration happens mostly in the furthest tips like the legs and in animals the tails.

Medicine has long established that ankle injuries heal faster than injuries o knees and hips, which often developed into arthritis.

“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 one of the researchers. “We call it our ‘inner salamander’ capacity.”

“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. We believe this is a fundamental mechanism of repair that could be applied to many tissues, not just cartilage.”