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Humans have a salamander-like ability to regenerate damaged body parts



Axolotl (pictured) have a remarkable ability to regenerate lost body parts.
Image : Research Institute of Molecular Pathology

Salamanders are known for their ability to regenerate, such as regrowth of whole limbs. We can not go through this biological trick, but new research proves a hitherto unknown human regenerative capacity, an ability that depends on our evolutionary past.

Our body has preserved the ability to repair injured or overworked cartilage in our joints, it says new research published today in Science Advances. Remarkably, the mechanics of this healing process are virtually the same as with amphibians and other animals to regenerate lost limbs.

"We call it our inner salamander ability."

The Scientists Those who have identified this previously unknown human ability are confident that their findings will lead to powerful new therapies for treating common joint disease and injury, including osteoarthritis , could lead. More radically, this healing mechanism "could be used to improve repair of the joints and provide a basis for the regeneration of the human limbs," the authors wrote in the article.

Some animals, such as axolotls zebrafish and bichir fish, are able to regenerate various body parts. The Axolotl is special in that it can regrow its limbs, organs and even parts of its brain. The fact that people can not grow whole limbs is hardly new, but scientists previously thought that we too are unable to repair damaged and deteriorated cartilage in our joints ourselves. To better understand this obvious human limitation, researchers from Duke University School of Medicine and Lund University sought to determine how long proteins actually remain in the cartilage.

"This led us to believe that the cartilage proteins of the knee were generally younger than those of the hip of people of similar age," wrote Virginia Kraus, professor of medicine at DUSM and co-author of the new study , at Gizmodo. "By younger, we mean that they have accumulated fewer modifications of their structure, which naturally accompanied aging over time. As a result, we wanted to examine ankle cartilage and, in fact, found that the same proteins were even younger. A "salamander-like" ability to regenerate damaged body parts. Study results ” data-poster-src=”” data-anim-src=”” data-cropped=”false” class=”dv4r5q-1 hEuYft”/>

Image : Alisa Weigandt / Duke Health

This previously unknown ability was discovered using proteomics, which enables scientists to study thousands of proteins instantly with small samples. This led Kraus and her colleagues to realize that the age of the cartilage proteins can be correlated with the body part they were in. The cartilage proteins, including collagen, in the ankles were young, in the knees they were middle-aged and in the hips they were old.

This is a notable finding that a similar phenomenon is observed in animals capable of limb regeneration, as tissue repair occurs in the distal sections, ie, their extremities (eg, tiptoe and tails).

"There is a concept in the field of appendage regeneration, according to which distal tissues can be better regenerated compared to the proximal tissue," the interior Prayag Murawala, postdoc at the Research Institute of Molecular Pathology in Vienna, Austria, in an email to Gizmodo.

"One example of this is the regeneration of the mouse digit," said Murawala, who was not involved in the new research. If the first finger bone of a mouse is amputated, it can regrow, he said, but if the finger is amputated on the second finger bone, it can not regenerate. The new paper "strengthens this hypothesis with further evidence" that "is consistent with previous research." Interestingly, this might explain why in humans the hips and knees need more time to heal than an ankle and why ankles are less prone to severe arthritis. As Kraus Gizmodo explained, it is twice as likely that the hip needs joint replacement and there is also evidence that "ankle osteoarthritis rarely progresses to a serious condition," she said. 19659017] Illustration for article entitled People have a "salamander-like" ability to regenerate damaged body parts. Study results ” data-poster-src=”” data-anim-src=”” data-cropped=”false” class=”dv4r5q-1 hEuYft”/>

Image : Alisa Weigandt / Duke Health

This regeneration process is regulated by a molecule known as microRNA. This molecule has proven to be very useful in the course of evolution and is found in many animal species. MiRNA controls "large amounts of critical genes for tissue regeneration," Kraus said, and it's more active in animals with the ability to regenerate whole limbs. MiRNA is also present in humans – a genetic remnant from our evolutionary past. We no longer use it for limb regeneration, but it does help repair our damaged cartilage. As the scientists demonstrated in the new work, the activity of miRNA depends on its position in the body, increasing activity in ankles compared to knees and hips.

The salamander link also appears to be responsible for the repair of articular tissue in the human limb, "said Ming-Feng Hsueh, DUSM molecular physiologist and first author of the work, in a press release. "We call it our" inner salamander "capacity."

Kraus said that she was "very hopeful" that these findings would be translated into actual therapies in the future. Because miRNAs are very "druggable," they could be "injected directly into a joint to speed repair and prevent osteoarthritis after joint injury or even slow or reverse osteoarthritis once it has developed," she said. And as the authors noted in the article, miRNAs along with other compounds yet to be identified could "lead to the future use of a" molecular cocktail "for the attempted … regeneration of limbs in humans."

In an E -Mail to Gizmodo Kenro Kusumi, a biologist from the School of Life Sciences at Arizona State University, who was not involved in the new study, said the "billion dollar question" was whether the activation of miRNAs 'doctors' regeneration of joints allows Randal Voss, a biologist at the University of Kentucky and an expert on the regenerative ability of Axolotls, said the new paper presents some "very interesting data on protein turnover and miRNA expression Voss, which also failed on the new Said that the "proposed" repair response in humans is significantly different than the repair method used by salamanders and other animals. "Gross cartilage bunch in damaged joints. "The relationship with miRNAs is interesting in both cases," he said, "but we still have much to learn about the requirements of miRNAs in human tissue repair and regeneration in salamanders. "In order to advance these findings, functional studies are required."

"It is amazing that humans separated us from the axolotl in evolution 400 million years ago, but there are many paths that are common between humans and axolotl," Murawala told Gizmodo still have a long way to go to explain why people can not regenerate, this study provides convincing evidence that there are many similarities between human and salamander limbs. "

Murawala said the new paper was" Significantly, and with a view to the future, these results will motivate researchers to focus on the distal parts of the animals to see why these parts regenerate better than the proximal ones A big question, he said, is whether tissue regeneration works better in the distal environment or in the distal cells, or both Hopefully these questions will one day answer the question of whether we can promote tissue regeneration in humans, "he said.


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