Human heart can fully recover after massive damage

The scientists report the case of a newborn that had suffered a massive heart attack in the first hours of life. It was caused by a blockage in a vital coronary vessel. "The baby's heart was severely damaged. Astonishingly, the baby recovered very quickly," said Bernhard Haubner, a cardiologist and researcher, and his colleague, Johanna Schneider, in an article just published in the journal "Circulation Research".

"One and one-half months after his severe illness, we were able to release the child. His heart is functioning normally. This observation proves for the first time that the human heart can fully recover after suffering massive damage," said Jörg-Ingolf Stein, head of pediatric cardiology at the Innsbruck Medical University. "This discovery has enormous potential. After all, cardiovascular diseases are among the most frequent causes of death worldwide".

Each year, 17 million people around the world die of cardiovascular diseases, 2 million of them in the EU alone (WHO). Even though medical care for cardiac patients has improved tremendously and the immediate fatality rate has dropped, most patients still face permanent damage leading to chronic heart failure. During a heart attack, cardiac muscle cells die and are replaced by scar tissue. But scar tissue cannot pump, which leads to limitations in cardiac function and a weakening of the heart muscle. So far, heart muscle cells lost in adults cannot be efficiently regenerated despite innovative approaches such as stem cell therapy.

Researchers already know from the animal research that lifelong regeneration of the heart is possible, for example in fish. "Along with a group from Texas, we were the first to describe complete cardiac regeneration following myocardial infarction in mice. But that only works if the mice are one week old or less," explained Bernhard Haubner, a clinician scientist working with IMBA director Josef Penninger. "To translate findings in model organisms such as mice into future therapies in humans, two key issues remain: what are the mechanisms and can cardiac regeneration indeed occur in humans? The latter we now observed, namely complete cardiac repair in a newborn human."

IMBA director Josef Penninger emphasizes the significance of this finding: "Every cardiologist dreams of being able to restore full function to a damaged heart, and now we have seen that this works in principle in humans. If we can figure out the key mechanisms that control cardiac repair in mice and other organisms, we might be also able to repair damaged heart muscle in humans in the future."