Heart muscles may soon be able to regenerate like other muscles
Heart failure remains an incurable condition. While medications can slow its progression, the only options for advanced cases are heart transplants or mechanical support through left ventricular assist devices
A new study from a collaborative research team has revealed that some patients with artificial hearts can regenerate heart muscle.
The discovery hold the potential to revolutionise heart failure treatments, which could impact millions of people globally, says Earth.
Heart failure: Current challenges
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Heart failure remains an incurable condition. While medications can slow its progression, the only options for advanced cases are heart transplants or mechanical support through left ventricular assist devices (LVADs).
These devices act as artificial hearts, helping the heart pump blood but offering no cure.
Dr. Hesham Sadek is the director of the Sarver Heart Center and chief of the Division of Cardiology at the University of Arizona College of Medicine.
"Skeletal muscle has a significant ability to regenerate after injury. If you're playing soccer and you tear a muscle, you need to rest it, and it heals," said Dr. Sadek. "When a heart muscle is injured, it doesn't grow back. We have nothing to reverse heart muscle loss."
Dr. Sadek co-led the study alongside international experts, investigating whether heart muscles possess any regenerative potential.
The project was funded by the Leducq Foundation Transatlantic Networks of Excellence Program, a collaborative initiative uniting American and European researchers.
Regeneration potential of heart
The research began with tissue samples from artificial heart patients. These samples were provided by Dr. Stavros Drakos and colleagues at the University of Utah Health and School of Medicine.
Teams from the Karolinska Institute in Stockholm, led by Dr. Jonas Frisén and Dr. Olaf Bergmann, used innovative carbon-dating methods to determine if these tissues contained newly generated cells.
The findings were remarkable: patients with artificial hearts regenerated muscle cells at over six times the rate observed in healthy hearts.
"This is the strongest evidence we have, so far, that human heart muscle cells can actually regenerate, which really is exciting, because it solidifies the notion that there is an intrinsic capacity of the human heart to regenerate," noted Dr. Sadek.
"It also strongly supports the hypothesis that the inability of the heart muscle to 'rest' is a major driver of the heart's lost ability to regenerate shortly after birth."
Role of "rest" in regeneration
Heart muscle cells actively divide in utero but stop shortly after birth, focusing solely on pumping blood without pause.
In 2011, Dr. Sadek published a study in Science that highlighted this shift. Later, in 2014, he presented evidence suggesting that patients with artificial hearts might experience some level of heart muscle regeneration.
These findings raised a critical question: does the mechanical support provided by LVADs mimic the "bedrest" needed for muscle recovery?
"The pump pushes blood into the aorta, bypassing the heart," said Dr. Sadek. "The heart is essentially resting."
The current study provided direct evidence that resting the heart through artificial support could enable muscle regeneration, marking the first time such irrefutable evidence has been shown in humans.
Variability in heart regeneration
Interestingly, only about 25% of artificial heart patients experience significant muscle regeneration. Dr. Sadek aims to uncover why some patients respond while others do not.
"It's not clear why some patients respond and some don't, but it's very clear that the ones who respond have the ability to regenerate heart muscle," he noted.
"The exciting part now is to determine how we can make everyone a responder, because if you can, you can essentially cure heart failure."
Implications for the future
The potential to enhance heart muscle regeneration through targeted molecular pathways could transform heart failure treatment.
"The beauty of this is that a mechanical heart is not a therapy we hope to deliver to our patients in the future – these devices are tried and true, and we've been using them for years," said Dr. Sadek.
This study builds on years of research and collaboration, offering renewed hope for millions of heart failure patients worldwide. With further investigation, the dream of curing heart failure could become a reality.
The study is published in the journal Circulation.
