Full Breakdown
Human Hearts Regenerate After Myocardial Infarction
5/3/2026, 10:56:34 PM
Human Hearts Regenerate After Myocardial Infarction
Scientists from the University of Sydney and Royal Prince Alfred Hospital have shown that human cardiomyocytes can divide and form new tissue after a myocardial infarction, the first evidence in living patients, published in *Circulation Research*.
Cardiovascular Disease Context and Unmet Need
Cardiovascular disease is the leading cause of death, accounting for 24 % of Australian fatalities. A heart attack can destroy up to one-third of cardiac cells, leading many survivors to heart failure—affecting about 144,000 Australians with only ~115 transplants per year. Mouse studies previously showed post-infarction cardiomyocyte mitosis, but human confirmation was lacking.
Study Design and Key Findings
Researchers collected pre-mortem heart tissue from patients undergoing coronary-artery bypass surgery at Royal Prince Alfred Hospital. Using a method developed by Professors Paul Bannon and Sean Lal, paired samples from diseased and healthy regions were obtained. Analysis revealed increased mitotic activity in infarcted zones and identified several proteins linked to regeneration in mice, establishing a living-human heart model for therapeutic testing.
Implications for Treatment
Heart failure requires transplantation, with only ~115 procedures for over 144,000 patients in Australia. Demonstrating intrinsic cardiomyocyte renewal suggests future therapies could boost natural repair, potentially lowering transplant demand and improving recovery after infarction. The authors note regeneration alone does not yet prevent acute damage.
Official Statements & Responses
Dr. Robert Hume noted the heart was previously thought irreparably damaged after infarction, but data show scarred tissue can generate new cells, opening regenerative avenues. Prof. Sean Lal stressed the goal of creating new cardiomyocytes to reverse heart failure and highlighted that tissue models provide reliable data for drug development.
Verbatim Quotes
- “Our research shows that while the heart is left scarred after a heart attack, it produces new muscle cells, which opens up new possibilities.” — Robert Hume, University of Sydney
- “Professor Sean Lal, senior author of the study from the School of Medical Sciences and a heart failure cardiologist at the Royal Prince Alfred Hospital, said, “Ultimately, the goal is to use this discovery to make new heart cells that can reverse heart failure.” — Sean Lal, Royal Prince Alfred Hospital
- “Using living human heart tissue models in our work means that we will have more accurate and reliable data to develop new therapies for heart disease.” — Sean Lal, Royal Prince Alfred Hospital
- “Already, our research using these samples has identified several proteins that have previously been shown to be involved in the regeneration of the heart in mice, which is a very exciting prospect to now translate to humans.” — Sean Lal, Royal Prince Alfred Hospital
What’s Next
The team will use the human heart model to test compounds that boost cardiomyocyte division and explore the proteins as targets. Funding from the R T Hall Trust supports these studies, which will need clinical trials before any regenerative therapy can be applied.
Conflicting Reports & Gaps
The study confirms cardiomyocyte mitosis in human infarcted tissue, but functional significance and long-term outcomes remain unquantified, and larger patient cohorts are needed to validate therapeutic potential.
