It turns out cartilage in human joints can repair itself
similarly to salamanders and zebrafish’s ability to regenerate
limbs. The new development was discovered by researchers at Duke
Health.
“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 in a statement[1]
senior author Virginia Byers Kraus, M.D., Ph.D., a professor in the
departments of Medicine, Pathology and Orthopedic Surgery at
Duke.
To make their discovery, Kraus and colleagues, including lead
author Ming-Feng Hsueh, Ph.D., had to find a way to determine the
age of proteins. They did so using internal molecular clocks
integral to amino acids.
Through spectrometry, they were able to identify when key
proteins in human cartilage, including collagens, were young,
middle-aged or old.
They found that the age of cartilage grew older as you moved up
the body. Therefore the cartilage in ankles is young, it is
middle-aged in the knee and old in the hips.
They deduced from this that cartilage age correlated with how
limb repair occurs in certain animals. Animals more readily
regenerate at the furthest tips, including the ends of legs or
tails.
microRNA
The researchers also found that molecules called microRNA are
responsible for regulating this process in animals. And since
these microRNAs are also found in humans, it means humans also
possess the capacity for joint tissue repair.
“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,” Hsueh said. “We call it our
‘inner salamander’ capacity.”
The researchers now believe that microRNAs could be turned into
medicines for treating arthritis.
“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.”
References
- ^
said in a statement
(corporate.dukehealth.org) - ^
study
(advances.sciencemag.org)