Stem cell patch repairs failing heart

Heart function in damaged hearts could be improved using a patch of stem cell derived heart muscle.

Heart muscle patches, made at University Medical Centre Göttingen (UMG) and University Medical Centre Schleswig-Holstein, Campus Lübeck (UKSH), Germany, have been attached to the surface of a heart in a patient with heart failure. The patches were made from heart muscle which had been derived from induced pluripotent stem cells. These muscle cells were embedded in a collagen gel and attached to the heart of a 46-year-old woman. After the patient received a heart transplant three months later, her original heart was analysed, and it was shown that the heart patch had survived and developed a blood supply, indicating it would survive long-term.

'We now have, for the first time, a laboratory-grown biological transplant available which has the potential to stabilise and strengthen the heart muscle,' Professor Ingo Kutschka, surgical director of the study at UMG explained.

The research, published in Nature, also details preclinical trials in rhesus macaque monkeys. Previous experiments using stem cell derived heart muscle have resulted in irregular heartbeats, tumours or immune rejection. Therefore, the research team first applied their heart patches to rhesus macaque hearts, showing no safety concerns and an improvement in heart function.

'We have shown in rhesus macaques that cardiac patch implantation can be applied to re-muscularised the failing heart. The challenge was to generate and implant enough heart muscle cells from rhesus macaque induced pluripotent stem cells to achieve sustainable heart repair without dangerous side effects such as cardiac arrhythmia or tumour growth,' said Professor Wolfram-Hubertus Zimmermann, of the department of pharmacology and toxicology at UMG and corresponding author of the study.

Heart failure is a leading cause of death worldwide, and currently the only cure is a heart transplant. A lack of donor availability means most patients will not receive a heart transplant. The researchers suggest that as the heart patches have been shown to improve heart function, they could increase a patient's quality of life while they wait for a transplant or be a permanent solution in themselves.

'The heart patch is an excellent example of translational research – from the laboratory to the clinic. It has the potential to replace mechanical support systems in certain cases and provide a permanent solution for patients,' said Professor Stephan Ensminger, surgical director of the study at UKSH.

However, there are still questions surrounding the long-term success of the heart patches. The patches need to survive on the heart for several months before they have a positive effect on heart function and so are not appropriate for emergency treatment. In addition, the improvement in heart function observed in the rhesus macaques will need to be confirmed in humans. This will be explored by the researchers in a follow-up clinical trial of 15 patients over several years.

'If these [larger trials] are positive, it could help to usher in a new era of heart failure treatment,' Professor James Leiper, director of research at the British Heart Foundation charity, who was not involved in the study said.