Human Hearts Capable of Regenerating Muscle Cells Following Heart Attacks: Study - Video

For decades, the human heart was seen as a one-chance organ-once damaged, forever scarred. But a groundbreaking discovery from Australia is now challenging that belief, revealing that the human heart may have a hidden ability to heal itself after a heart attack.

In a study published in Circulation Research, researchers from the University of Sydney and Australia’s Baird Institute have shown, for the first time, that new heart muscle cells can form in the human heart following a heart attack. This discovery opens the door to future regenerative therapies that could help repair damaged hearts and potentially reverse heart failure.

Heart attacks occur when blood flow to the heart is blocked, causing large numbers of heart muscle cells to die. Traditionally, scientists believed these lost cells were replaced only by scar tissue, permanently weakening the heart’s ability to pump blood. While limited heart muscle regeneration had been observed in animals like mice, it had never been clearly demonstrated in humans—until now.

To uncover this phenomenon, the research team analyzed living heart tissue collected from patients undergoing bypass surgery at Royal Prince Alfred Hospital in Sydney. Using advanced cellular and molecular techniques, they examined these samples for signs of mitosis—the process by which cells divide to create new cells. The scientists found clear evidence that, alongside scar formation, new heart muscle cells were being produced in areas affected by a previous heart attack.

Robert Hume, the study’s first author, explained that these finding overturns long-held assumptions about heart damage being permanent. While the regenerated cells do not fully replace all lost tissue, their presence proves that the human heart retains some natural repair capacity.

The study’s senior author, Professor Sean Lal, emphasized that the real promise lies ahead. By understanding how and why these new cells form, scientists hope to develop treatments that can boost this natural process, encouraging the heart to regenerate more effectively after injury.

This discovery provides crucial groundwork for regenerative medicine, offering fresh hope that future therapies could help the heart heal itself—transforming how heart disease is treated in the years to come.

REFERENCE: Hume, Robert D. et al.; Human Hearts Intrinsically Increase Cardiomyocyte Mitosis After Myocardial Infarction; Circulation Research; doi: 10.1161/CIRCRESAHA.125.327486