New hope for patients: A tissue patch grown from stem cells can help people with severe heart failure, as a first clinical study has now confirmed. Accordingly, this “heart patch” strengthens the damaged heart muscle and improves the heart’s pumping function. This increases the patients’ cardiac performance and quality of life – they continue to benefit from it four years after the “heart patch” was implanted, as the doctors report. This is an important advance in the treatment of heart failure.
Heart failure is one of the most common serious heart diseases worldwide – around four million people in Germany alone are affected by such heart failure. It occurs when parts of the heart muscle do not receive enough oxygen due to a heart attack or other illness and die. Instead of the contractile muscle cells, stiff scar tissue forms and the heart’s pumping capacity continues to decrease.
“The therapies available today can often slow down the progression of the disease, but cannot replace damaged heart muscles,” says senior author Wolfram-Hubertus Zimmermann from the University Medical Center Göttingen. In severe cases, those affected can only survive with a heart transplant or an artificial heart.
(Video: Göttingen University Medical Center)
A “plaster” made up of millions of cells
But now there is hope: A research team led by Zimmermann has developed a tissue patch that strengthens the damaged heart muscle tissue and can partially replace it. The starting material for the “heart patch” is induced pluripotent stem cells – adult blood cells that have been returned to their immature state in the laboratory. Using special nutrient solutions, messenger substances and a collagen framework, the researchers use these stem cells to grow small pieces of tissue made from heart muscle cells and connective tissue.
A single heart patch consists of around 20 such pieces of tissue and contains a total of 40 to 200 million cells, as the team explains. In a minimally invasive operation, the heart patch is sewn onto the outside of the damaged heart. There, the cultured tissue is intended to form a new layer of heart muscle, approximately three to four millimeters thick, which is intended to stabilize the weakened heart muscles and provide long-term support. “Our goal is to produce new, functioning heart muscle tissue and thus specifically support the weakened heart,” explains Zimmermann.
There were already initial successes at the beginning of 2025: tests with 14 rhesus monkeys and a first human test patient showed that the heart patch is growing and developing. After three to six months, the heart wall at this point thickens and contracts more strongly than before, as the researchers reported at the time.
Positive effect also in the first clinical study
Now a further step has been taken: for the first time, a clinical study confirms that the heart patch works in patients with severe heart failure. In the first phase of the study, which started in 2021, the team led by first author Ahmad-Fawad Jebran from the Göttingen University Medical Center determined how large the heart patches should be in order to be tolerated. The maximum number of cultured cells was around 800 million. Heart patches of this size were then initially used in 20 patients.
The first results are now available – and they are positive. In the 12 patients who stayed throughout the study period, the heart patch grew and the heart wall thickened by an average of 4.5 millimeters, as Jebran and his colleagues found. After just three months, the heart’s pumping performance had improved slightly, although initially only by a few percentage points. Nevertheless, patients report an improved quality of life.
New opportunity for heart patients
Some of the patients have now been living with the heart patch for more than four years – and are showing continued improvement in their heart function. “Our results show for the first time in a larger clinical study that it is fundamentally possible to restore heart muscle function in people with advanced heart muscle weakness,” says Zimmermann. “This confirms important findings from our many years of research work.”
According to the research team, the heart patch opens up the opportunity to help people with severe heart failure. Follow-up studies with larger numbers of patients have already begun, including some in Germany and other European countries, but also in the USA. “The heart patch could become an additional treatment option for selected patients with severe heart failure in the future,” says co-author Ingo Kutschka from the University Hospital of Basel.
Source: Ahmad-Fawad Jebran (University Medicine Göttingen) et al., New England Journal of Medicine, 2026; doi: 10.1056/NEJMoa2513525