Researchers have developed a pioneering method to mend damaged hearts without open-heart surgery, an advance that could one day transform the treatment of heart failure.
The new approach utilises lab-grown heart tissue created from reprogrammed adult stem cells, which is delivered through a tiny incision rather than a surgically opened chest cavity. In preclinical testing, the stem cell patch restored heart function and improved healing.
Wuqiang Zhu, senior author of the study published in Acta Biomaterialia and a cardiovascular researcher at Mayo Clinic in Arizona, said: ‘For patients with severe heart failure, there are very few options beyond mechanical pumps or transplants. We hope this approach will offer a new way to repair their own hearts.
‘The adult human heart doesn’t regenerate once cells are lost. That’s why heart failure, especially chronic heart failure due to the loss of functional cardiac muscle, is often difficult to treat; the muscle simply cannot repair itself.’
For years, scientists have been working on ways to replace damaged tissue with healthy heart cells derived from stem cells. Early efforts showed promise, but most required open-heart surgery.
By reprogramming ordinary adult cells, such as skin or blood cells, into induced pluripotent stem cells (iPSCs), researchers can coax them into becoming replacement heart cells.
In collaboration with engineers at the University of Nebraska Medical Centre, Mayo researchers developed a flexible, paper-thin patch made of nano- and microfibres-coated with gelatin. This hybrid scaffold supports a blend of human heart muscle cells, blood vessel cells and fibroblasts to create a living, beating piece of heart tissue. Before transplantation, the tissue is infused with bioactive factors such as fibroblast growth factor 1 and CHIR99021 that encourage the growth of new blood vessels and help the cells survive once they are in place.
Dr Zhu explained: ‘The beauty of this design is that it can be folded like a piece of paper, loaded into a slender tube, and delivered precisely where it’s needed through a small incision in the chest. Once in place, it unfolds and adheres naturally to the heart’s surface.’
Instead of using stitches, the team used a biocompatible surgical adhesive that holds the patch in place while minimising additional trauma to the surrounding tissue.
Testing in preclinical models demonstrated that the minimally invasive method improved heart function, reduced scarring, enhanced vascular growth, and lessened inflammation compared to conventional approaches.
Dr Zhu said: ‘Our results show that these engineered tissues not only survive but actually help the heart heal itself. That's the ultimate goal: to replace what's lost and restore function.’
The research aligns closely with Mayo Clinic's Genesis Initiative, which aims to accelerate discoveries that restore or regenerate human organs and tissues.
The Mayo Clinic team plans to advance this work through larger-scale preclinical testing to ensure the therapy's safety and effectiveness before moving to human clinical trials, a process that Dr Zhu estimates could take five years or more.
