Humans have the ‘untapped’ ability to regenerate body parts just like salamanders, scientists claim beweren
Like salamanders, humans have an “untapped” ability to regenerate parts of their bodies, such as a lost limb, a team of researchers said.
The axolotl, a Mexican salamander nearly extinct in the wild, is a “champion of regeneration” that can mimic almost any body part, including the brain.
Studying this unusual amphibian helped experts at the MDI Biological Laboratory in Bar Harbor, Maine, conclude that humans have an “untapped” ability to regenerate.
They focused on understanding why the axolotl doesn’t form a scar — or why it doesn’t respond to injury in the same way as the mouse and other mammals.
They found that immune cells called macrophages promoted the growth of tissue cells in the salamander but caused scarring in the mouse.
The team says that scarring may be responsible for blocking regeneration in mammals and that in the future, blocking brain pathways that lead to scarring could allow humans to regrow lost limbs or improve overall health. improve.
The axolotl, a Mexican salamander now nearly extinct in the wild, is a favorite model in regenerative medicine research due to its unique status as a wildlife champion of regeneration.
AXOLOTL (AMBYSTOMA MEXICANUM)
Axolotl (Ambystoma mexicanum), also known as the Mexican walking fish, is known for its ability to regenerate.
The amphibian is critically endangered, nearly extinct in the wild, but was originally found in lakes around Mexico City.
Unlike most amphibians, they do not undergo metamorphosis upon reaching adulthood, remain in the water and have gills rather than move to land.
They can grow up to 12 inches tall, but most are closer to nine inches tall as full grown adults.
They have a unique ability to regenerate and instead of being healed by scaring, they can produce new limbs in just a few months.
They can also regenerate tails, central nervous system, eyes and heart.
They can even restore less vital parts of their brains and take transplants from others without any problem.
dr. James Godwin and colleagues compared molecular signaling after injury in the axolotl salamander with that of an adult mouse, which has limited regenerative capacity.
Instead of regenerating lost or injured body parts, mammals typically scar at the site of an injury, creating a barrier to regeneration, Godwin explained.
“Our research shows that humans have untapped potential for regeneration,” he explained, adding that solving the problem of scarring could unlock that latent regenerative potential.
‘Axolotls do not cause scarring, allowing regeneration to take place. But once a scar has formed, the game is over in terms of regeneration. If we could prevent scars in people, we could improve the quality of life for so many people.’
The axolotl is a favorite model in regenerative medicine research because of its unique status as a natural champion of regeneration.
While most salamanders have some regenerative ability, the axolotl can regenerate almost any body part, including brain, heart, jaws, limbs, lungs, ovaries, spinal cord, skin, tail, and more.
Since mammalian embryos and juveniles have the ability to regenerate — for example, human infants can regenerate heart tissue and children can regenerate fingertips — it’s likely that adult mammals retain the genetic code for regeneration.
This creates the prospect that one day drugs could be developed that would encourage people to regenerate tissues and organs lost through disease or injury, rather than scarring.
Godwin compared immune cells called macrophages in the axolotl to those in the mouse in hopes of discovering which aspect of axolotl promotes regeneration.
The research builds on previous studies in which Godwin found that macrophages are crucial for regeneration.
Previous studies showed that when macrophage supplies in the salamander run out, the axolotl scars instead of regenerating, just like mammals do.
Macrophage signaling in the axolotl and mouse was similar when exposed to bacteria, fungi and viruses.
This changed when it came to physical injury, where macrophage signaling in the axolotl led to new tissue growth, but in the mouse led to scarring.
This graphic summary shows the divergence between molecular signaling in the immune system of the axolotl, a Mexican salamander that can easily regenerate limbs and other body parts, and the adult mouse, which cannot.
They found that the signal response of a class of proteins called toll-like receptors (TLRs), which allow macrophages to recognize a threat such as infection or injury, was “unexpectedly aberrant” in the axolotl and mouse.
“The finding offers an intriguing insight into the mechanisms that control regeneration in the axolotl,” Godwin said.
The discovery of an alternative signaling pathway compatible with regeneration could eventually lead to regenerative therapies for humans.
While regrowth of a human limb may not be realistic in the short term, there are significant opportunities for therapies to improve clinical outcomes in diseases where scarring plays an important role in pathology.
A team of scientists led by James Godwin has come one step closer to unraveling the mystery of why salamanders can regenerate while adult mammals cannot with the discovery of differences in molecular signaling that promote regeneration in the axolotl.
“We are beginning to understand better how axolotl macrophages are ready for regeneration, which will bring us closer to being able to pull the levers of regeneration in humans,” Godwin said.
“For example, I imagine I could use a topical hydrogel on the site of a wound laced with a modulator that alters the behavior of human macrophages to more closely resemble that of the axolotl.”
“Scientists at the MDI Biological Laboratory have relied on comparative biology to understand human health since its inception in 1898,” said Dr. Hermann Haller, the institution’s president.
“The discoveries made possible by James Godwin’s comparative studies of the axolotl and the mouse are proof that the idea of learning from nature is as valid today as it was over one hundred and twenty years ago.”
The article about the research was published in the journal Development Dynamics.
HOW EARLY DO THE BRAIN GUIDE TISSUE GROWTH?
New research suggests that the brain’s role in the body may begin much earlier than previously thought.
Scientists at Tufts University have discovered, by removing the brains from day-old frog embryos, that bioelectrical signals in the developing brain help to form muscles and tissues and protect the embryo from developmental defects.
In a second study published in February, the team showed that these patterns can be predicted and mapped to avoid defects caused by harmful substances.
For this, the embryos were exposed to nicotine.
Frog embryos (bottom) and bioelectric patterns (top) are shown in the image above, with normal patterns shown on the left, disrupted in the presence of nicotine (center) and restored when HCN2 is added, right
The findings could pave the way for better ways to address birth defects and injuries in humans, the researchers say, or even to regenerate complex organs.
“Studies focused on gene expression, growth factors and molecular pathways have given us a better but still incomplete understanding of how cells arrange themselves in complex organ systems in a growing embryo,” said Professor Michael Levin, Ph.D., corresponding author of the study and director of the Allen Discovery Center at Tufts University, regarding the latest study.
‘We are now starting to see how electrical patterns in the embryo drive large-scale patterns of tissues, organs and limbs. If we can decipher this electrical communication between cells, we may be able to use it to normalize development or support regeneration in the treatment of disease or injury.”