On Jan. 29, 2025, researchers from the University Medical Center Göttingen announced they have shown that patches of muscle grown from stem cells can help to repair a failing heart, in a clinical trial that tested the procedure on a 46-year-old woman.

The woman, who had a heart attack in 2016 and later developed heart failure, had an operation to implant 10 patches of 400 million cells on the surface of her heart. Her condition then remained stable for three months, long enough for her to receive a heart transplant. Scientists who examined her old heart found that the implanted muscle patches had remained in place and formed blood vessels.

The results of the trial, which took place in 2021, were published in Nature on 29 January, alongside findings from earlier studies that tested muscle patches containing either 40 million or 200 million cells in rhesus macaques (Macaca mulatta).

The research team engineered iPSCs to grow into heart muscle and connective tissue. They mixed these cells with collagen gel to create patches, and developed a minimally invasive procedure to place them on the surface of the heart.

The treatment is not intended to replace the need for a full transplant, but it can help people with advanced heart failure who are waiting for a heart to become available..