Science

Humans have 'salamander-like' ability to regrow cartilage: study

A Mexican salamander. File photo for representative purpose.   | Photo Credit: AFP

Salamanders, zebrafish and Mexican walking fish are known to be experts at regenerating lost limbs. They pull off this extraordinary feat by using a circuit of microRNA (miRNA) in their body. Now a research from Duke University, U.S. have shown that these microRNAs are also found in humans and may help in cartilage regeneration.

The team studied the human lower limb cartilages and found that the microRNAs were highest in ankles compared to knees and hips. Also, the top layer of cartilage had a higher concentration compared to deeper layers of cartilage.

"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," says senior author Virginia Byers Kraus from the Departments of Medicine, Pathology and Orthopedic Surgery at Duke in a release. “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."

The team quantified the expression of three miRNA (miR-21, miR-31, and miR-181c) in the cartilage and found that they help activate the collagen proteins.

They used mass spectroscopy studies and analysed the different proteins in the cartilages and their ages. They noted that the newly formed ones had few or no amino acid conversions and older proteins had many. Also cartilage in the ankles were young, and those at the knee were middle-aged. Hips had the oldest cartilage. This explains why the ankles heal quicker, while the knees and hip takes time and even turn into severe arthritis. This conclusion also correlates with the findings in many other animals who easily regenerate their furthest tips such as tails.

“We are testing upper limb joints currently. Our hypothesis is that they will show the same effect with the strongest regeneration in the finger and wrist joints compared to the shoulder,” adds Dr. Kraus in an email to The Hindu. The results were published in the journal Science Advances.

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Printable version | Jan 21, 2021 8:19:03 AM | https://www.thehindu.com/sci-tech/science/humans-have-salamander-like-ability-to-regrow-cartilage-study/article29701242.ece

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