A heart pavement is composed of several hexagonal parts.
Photo: dpa/university medicine Göttingen
The waiting times for donor hearts in Germany are long and many patients die before a suitable organ is found for them. A heart transplant is usually necessary when there is severe heart muscle weakness – for example as a result of coronary heart disease, heart muscle inflammation or a heart attack. If the heart is too weak, but no donor organ has yet been found, a mechanical heart pump can also be used to bridge.
An alternative treatment option could only be in the medium term, “plaster” made of artificially bred heart tissue that are applied to the damaged hearts, as a now published study of rhesus monkeys showed. At the same time, the “heart plasters” are already implanted in clinical studies human patients. “In the animal model, we were able to show that the implantation of heart paves is suitable for the permanent structure of the heart muscle in heart failure,” explains Wolfram-Hubertus Zimmermann from the Institute of Pharmacology and Toxicology of the University Hospital Göttingen, which has led the monkey study and now with his team further clinical Studies carried out to heart patients. 14 patients with severe heart failure should receive a heart pavement this year as part of the study, in total it should be 53 patients in the course of the study.
Cells are reprogrammed
What is implanted there is fabric from induced pluripotent stem cells (IPS). Human cells are reprogrammed twice: First, for example, cells made of connective tissue are turned back to stem cells. And these stem cells are obtained to develop into cardiac muscle cells. The approximately 100 square centimeters of “heart pavement” consist of a mixture of heart muscle and connective tissue cells and are already able to beat in the cultural shell, as Zimmermann reports.
The treatment of heart attack patients was simulated in the monkey model. This means that the hearts of the rhesus monkeys were first weakened, then heart tissue from the described method was implanted from the outside. After three to six months, these heart tissue had grown and had significantly strengthened the affairs’ overviews, said Zimmermann.
The situation was similar with a 46-year-old patient whose heart could already be examined because she had received a donor organ. On the explaned heart, it was shown “that heart muscle cells that we implant through a heart pavement actually stay where we are implanted,” says Zimmermann. The pumping performance of the weakened heart chamber had also increased by a few percentage points.
No tumor formation found
The previous results of rhesus monkeys and people show that the heart fabric from stem cells meets fundamental requirements: it remains in the right place, has a stabilizing effect and supports the heart when beating. But the question is just as important whether the non -body tissue can also do damage. Alessandra Moretti, professor of regenerative medicine cardiovascular diseases at the Technical University of Munich, which also deals with stem cells and is not involved in the study, emphasizes that the implants have so far not caused cardiac arrhythmias. In addition, they would not have led to the formation of tumors – a well -known risk when using products from pluripotent stem cells.
Another problem with the use of IPs is that the immune system of patients must be suppressed after the implantation so that the new tissue is not rejected. In parallel, research is also carried out on so -called hypoimmuns, which do not cause any rejection reactions in the body. But: “Nobody knows whether a hypoimmune cell does not ultimately represent a great risk of tumor,” explains Zimmermann. Because the body could not repel such cells, even if they degenerated.
For the current heart pavement, if things go well, an approval study could begin in 2026. In the event of admission, it would probably be about bridging the time until the transplantation of a donor heart. This will be costly at first, says Zimmermann; The question then is how it cuts off compared to mechanical pump systems. The doctor hopes to be able to treat 20,000 patients a year with his preparation.With agencies
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