The gecko can fully heal its heart without scar tissue
A research team from Aarhus University has mapped how geckos regenerate damaged heart tissue. This could make the gecko an important new model organism in the quest to understand the body's ability to repair itself.
Why can some animals repair damaged organs, while the human body often must settle for patching up injuries with scar tissue? This is one of biology's major fundamental questions—one that researchers have been pursuing answers to for years.
Now, research has moved a step closer to an answer after a research team from Aarhus University demonstrated that the scaly reptile, the gecko, can repair damaged heart tissue without forming scars.
The finding could have a major impact on regenerative research—the study of how the body can repair and regenerate damaged tissue. So says Tobias Wang, Professor of Zoophysiology at Aarhus University.
“For years, the zebrafish has been a key lab animal in heart regeneration research because it can restore damaged heart tissue. But the zebrafish is far removed from humans when it comes to the heart and circulatory system. That’s why we’ve been looking for an animal that can bridge the gap between fish and human physiology,” he says, explaining the rationale behind the study, which was conducted in collaboration with researchers from Charles University in Prague and published in The Physiological Society.
Magic in the gecko’s heart
Reptiles like the gecko have a heart with a compact muscle layer and higher blood pressure, making them more similar to humans. This makes the gecko a model that, in certain areas, is closer to the human heart and circulatory system, Tobias Wang explains.
In the laboratory study, the researchers gained access to the gecko's heart and applied a brief freeze-injury using a metal plate dipped in liquid nitrogen. The ice-cold plate triggered controlled cell death, mimicking the tissue damage that occurs when a blood clot cuts off the blood supply to the heart. In a mammal, such damage would typically leave behind stiff scar tissue—assuming one survives the heart attack—and the heart never fully returns to its original state.
However, in the gecko’s heart, something remarkable happened: instead of forming stiff scar tissue, the heart began to repair itself.
During the first week after the freezing and cell death, the tissue lost its function, but in week two, the heart tissue began to regenerate. After 21 days, measurements of the heart's electrical activity showed that signals were once again spreading across the entire ventricle. After four weeks, the damaged part of the heart had regenerated, and cardiac function was fully restored.
A promising new model animal
This is the first time that this regenerative capacity has been documented and mapped so precisely in a reptile species, Tobias Wang notes:
“In an evolutionary and research-historical light, this means that we can now confidently 'check off' that reptiles possess this ability. Consequently, we now have a new and more representative model organism for research purposes, precisely because the gecko has a physiology with higher blood pressure and a compact heart structure that more closely resembles a human heart,” he says.
Although a ready-to-use treatment for heart patients will not be available tomorrow, the discovery is an important step for both biological and medical research.
Still unanswered questions
“Knowing that geckos can be used as a more accurate model for human heart healing fills the gap in the transition from so-called lower species to more complex mammals. It isn't a quick fix for treating heart disease, but a crucial step toward understanding which biological buttons need to be pushed if the human body is one day to learn how to repair itself.”
There are still plenty of unanswered questions, Tobias Wang emphasizes. One of the most fundamental is why mammals lost the ability to regenerate in the first place when we evolved a high metabolic rate and warm bodies.
The next step for the research team is to study snakes. They have even higher blood pressure than geckos, and preliminary observations suggest that their hormonal response during nutrient absorption may accelerate the healing process even further.
Why can some animals repair damaged organs, while the human body often must settle for patching up injuries with scar tissue? This is one of biology's major fundamental questions—one that researchers have been pursuing answers to for years.
Now, research has moved a step closer to an answer after a research team from Aarhus University demonstrated that the scaly reptile, the gecko, can repair damaged heart tissue without forming scars.
The finding could have a major impact on regenerative research—the study of how the body can repair and regenerate damaged tissue. So says Tobias Wang, Professor of Zoophysiology at Aarhus University.
“For years, the zebrafish has been a key lab animal in heart regeneration research because it can restore damaged heart tissue. But the zebrafish is far removed from humans when it comes to the heart and circulatory system. That’s why we’ve been looking for an animal that can bridge the gap between fish and human physiology,” he says, explaining the rationale behind the study, which was conducted in collaboration with researchers from Charles University in Prague and published in The Physiological Society.
Magic in the gecko’s heart
Reptiles like the gecko have a heart with a compact muscle layer and higher blood pressure, making them more similar to humans. This makes the gecko a model that, in certain areas, is closer to the human heart and circulatory system, Tobias Wang explains.
In the laboratory study, the researchers gained access to the gecko's heart and applied a brief freeze-injury using a metal plate dipped in liquid nitrogen. The ice-cold plate triggered controlled cell death, mimicking the tissue damage that occurs when a blood clot cuts off the blood supply to the heart. In a mammal, such damage would typically leave behind stiff scar tissue—assuming one survives the heart attack—and the heart never fully returns to its original state.
However, in the gecko’s heart, something remarkable happened: instead of forming stiff scar tissue, the heart began to repair itself.
During the first week after the freezing and cell death, the tissue lost its function, but in week two, the heart tissue began to regenerate. After 21 days, measurements of the heart's electrical activity showed that signals were once again spreading across the entire ventricle. After four weeks, the damaged part of the heart had regenerated, and cardiac function was fully restored.
A promising new model animal
This is the first time that this regenerative capacity has been documented and mapped so precisely in a reptile species, Tobias Wang notes:
“In an evolutionary and research-historical light, this means that we can now confidently 'check off' that reptiles possess this ability. Consequently, we now have a new and more representative model organism for research purposes, precisely because the gecko has a physiology with higher blood pressure and a compact heart structure that more closely resembles a human heart,” he says.
Although a ready-to-use treatment for heart patients will not be available tomorrow, the discovery is an important step for both biological and medical research.
Still unanswered questions
“Knowing that geckos can be used as a more accurate model for human heart healing fills the gap in the transition from so-called lower species to more complex mammals. It isn't a quick fix for treating heart disease, but a crucial step toward understanding which biological buttons need to be pushed if the human body is one day to learn how to repair itself.”
There are still plenty of unanswered questions, Tobias Wang emphasizes. One of the most fundamental is why mammals lost the ability to regenerate in the first place when we evolved a high metabolic rate and warm bodies.
The next step for the research team is to study snakes. They have even higher blood pressure than geckos, and preliminary observations suggest that their hormonal response during nutrient absorption may accelerate the healing process even further.
Behind the research result
Study type:
Experimental animal study involving 28 adult female leopard geckos (Eublepharis macularius).
External funding:
The study is supported by the Czech Ministry of Education, Youth and Sports through the Cooperatio programs for Cardiovascular Science and Dental Medicine, as well as the National Institute for Cancer Research, Programme EXCELES (project LX22NPO5102), funded by the EU's Next Generation EU program.
Link to scientific publication:
https://physoc.onlinelibrary.wiley.com/doi/10.1113/EP093688:
Contact:
Professor Tobias Wang
+45 51 37 77 37
Tobias.wang@bio.au.dk