Kelly, a curious listener, ignited a quest into human regeneration after questioning if our tongues can regrow. Joined by Dr. Elly Tanaka, an expert on axolotls—the amphibians renowned for regrowing limbs—they explore why humans lag behind in regeneration. The conversation dives into the evolutionary origins of regenerative abilities, potential dormant genes in humans, and innovative lab-grown heart organoids. Kelly even showcases her new axolotl tattoo, symbolizing this fascinating journey into the limits and possibilities of bodily regeneration.
Axolotls possess extraordinary regenerative abilities, enabling them to regrow limbs and organs, providing insights into potential human medical advancements.
While humans exhibit limited regeneration primarily through cellular turnover, understanding the evolutionary origins of these abilities could unlock new therapeutic possibilities.
Deep dives
The Regenerative Marvel of Axolotls
Axolotls, a unique species of salamander, exhibit remarkable regenerative abilities, allowing them to regrow lost limbs and even internal organs. Unlike humans, whose regenerative capabilities are severely limited, axolotls can replace body parts following injury, with regeneration occurring at a molecular level. When an axolotl loses a limb, the wound heals quickly, and specific cells known as fibroblasts revert to a stem cell-like state, enabling them to become the precise cells needed for regeneration. This intricate process highlights the axolotl's potential as a key area of study for regenerative medicine, showcasing biological mechanisms that could inspire future treatments for human injuries.
Human Regeneration: What We Can and Cannot Regrow
While humans possess some regenerative capabilities, these are mostly limited to cellular turnover rather than full organ regrowth. For example, the liver can regenerate to some extent after damage, and the skin can heal superficial injuries. However, organs like the heart and brain do not have this capacity, which raises questions about why humans have evolved this way. The balance between maintaining complex organ function and the risks associated with cellular division leads to limited regeneration, focusing more on repair than full renewal.
Evolutionary Insights into Regeneration
Regenerative abilities are not unique to axolotls; they are a characteristic shared among a broader group of salamanders and other species, such as certain fish. Research suggests that these abilities may have existed in ancient amphibians, indicating that modern species inherited regeneration traits from their ancestors. By studying the molecular frameworks governing regeneration in axolotls, researchers aim to uncover potential genetic blueprints that may also exist in humans but have become dormant over time. This evolutionary perspective opens up possibilities for understanding how regeneration can be reactivated or adapted within human biology.
The Future of Regenerative Medicine
Advancements in regenerative medicine hint at the potential for developing organs from human cells, enabling scientists to grow tissues like heart organoids for research and potentially transplantation. Researchers are exploring cellular manipulation techniques, such as inducing pluripotent stem cells to revert back to a stem cell-like state and differentiate into heart cells. Although challenges remain in engineering fully functional organs, the progress being made suggests that future therapies could harness regeneration in ways previously deemed impossible. This ongoing research holds promise for treating conditions that currently lack effective solutions, such as heart disease, by potentially allowing for the growth of replacement organs.
It would be quite a superpower to regrow entire body parts. CrowdScience listener Kelly started pondering this after a discussion with her friend on whether human tongues could regrow. Finding out that they couldn't, she asked us to investigate the extent of human regenerative abilities.
Presenter Alex Lathbridge travels to Vienna, a hotbed of research in this area. He meets an animal with much better powers of regeneration than humans - the axolotl. In Elly Tanaka’s lab he finds out how she studies their incredible abilities – and shows off his new axolotl tattoo.
Why can these sweet-looking salamanders regrow entire limbs while we can’t even regrow our tongues? Palaeontologist Nadia Fröbisch has looked into the evolutionary origins of regeneration, and it goes a lot further back than you might think.
And in fact, even humans are constantly regenerating, by renewing the building blocks of our bodies: cells. New cells grow and replace old ones all the time – although, in some parts of the body, we do keep hold of the same cells throughout our lives.
However, cell turnover isn’t the same as regrowing entire organs or limbs. But can we grow new body parts in the lab instead? We meet Sasha Mendjan, who creates heart organoids using our cells’ innate ability to self-organise. How far off are we from implanting organs, grown from a patient’s stem cells, back into the human body?
Contributors:
Dr Elly Tanaka, Institute of Molecular Biotechnology (IMBA)
Prof Martin Hetzer, Institute of Science and Technology Austria (ISTA)
Prof Nadia Fröbisch, Natural History Museum Berlin
Dr Sasha Mendjan, Institute of Molecular Biotechnology (IMBA)
Presenter: Alex Lathbridge
Producer: Florian Bohr
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Bob Nettles
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