Researchers there have discovered that the cartilage in joints of humans have the potential to repair itself in a similar way that salamanders and zebrafish can regenerate their limbs. This discovery was made at Duke Health (Duke University Health System) which includes several hospitals that do research, clinical care and education.
Virginia Byers Kraus, M.D., Ph.D., and a professor in the departments of Medicine, Pathology and Orthopedic Surgery at Duke and senior author of the study, states that, ”We believe 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.”
Kraus, along with lead author of the study, Ming-Feng Hsueh, Ph.D. and their colleagues made this discovery by determining the age of proteins. This was accomplished by using internal molecular clocks which are integral to amino acids.
With the use of spectrometry the research team was able to identify when certain key proteins in human collagens and cartilage were either young, middle-aged or old.
Their findings revealed that cartilage grew older as they moved up the body, showing that cartilage in the ankles were young, cartilage in the knees were of middle-age and that they were old in the hips.
Researchers deduced from this revelation that cartilage age is linked to how limb repair happens in certain animals and that regeneration takes place at the furthermost tips or ends of legs and tails.
They also discovered that the molecules responsible for regulating this regenerative process in animals are called microRNA. What is interesting is that microRNA are also found in humans which means that humans also possess the capacity for joint tissue and limb repair.
Hsueh, and his colleagues refer to these regulators of regeneration of limbs in salamanders to be the same controllers for tissue repair in humans, as ‘inner salamander capacity.’
Hsueh and Kraus’ team of researchers believe that microRNAs can be developed into medicines for the treatment of arthritis in humans.
Kraus states that the team believes these regulators could be boosted to completely regenerate degenerated cartilage in a person’s arthritic joint. And if they could figure out the missing regulators that are in salamanders they might be able to add those missing components and someday develop a way to regenerate all or parts of an injured human limb. If they could discover this, it could end up being a fundamental mechanism of repair for all tissues not just to cartilage .