Israeli scientists have isolated a molecule that promotes heart cell regeneration, according to the results of a new study published in Nature magazine, a discovery that could offer hope to millions of sufferers of cardiovascular diseases around the world.
The study, led by Rehovot’s Weizmann Institute of Science in cooperation with several other schools in Israel and in the US, examined the effect of an embryonic protein on adult heart regeneration.
While heart regeneration in mammals has been observed during the prenatal stage, it is virtually impossible for the blood-pumping organ to heal after birth. Any damage to the heart from that point on, through heart attacks or other maladies, is there to stay.
Artistic illustration of a heart
Even worse, the healthy heart muscle cells, or cardiomyocytes, are replaced by scar tissue that places further burden on the remaining healthy cells.
Thus, any damage to the heart only increases the risk of further degeneration and eventual failure.
In a study in Nature Cell Biology in April, Professor Eldad Tzahor, an expert in embryonic development with a focus on the heart, found that a protein called ERBB2, in concert with other proteins and protein receptors, controlled — and stymied — the development of heart tissue, so that it was able to grow only up to a week after birth, in mice. He and his colleagues then went on to discover, through various experiments, that ERBB2 — if activated with great precision in a short interval after a heart attack — could nearly completely heal a heart within several weeks.
Researchers studied a protein called Agrin, common in fetal hearts, which rapidly disappears after birth. They now believe Agrin, which resides in the space between prenatal heart cells, controls the process of cardiomyocyte regeneration.
The scientists extracted Agrin from the hearts of newborn mice, which retain the protein for about a week after birth, and tested it in various environments, to highly encouraging results.
When tested in lab cultures, Agrin was seen to promote cardiomyocyte growth in the tissue of adult hearts — both mice and human.
And when injected into the damaged hearts of live mice, Agrin appeared to heal them and restore them to regular working order within weeks, greatly reducing scar tissue and replacing it with new healthy muscle cells.
“Clearly this molecule sets a chain of events in motion,” Prof. Eldad Tzahor of the Weizmann Institute said.
Current efforts by the Tzahor team are focusing on novel mechanisms to regenerate the heart after birth, a major challenge in current biomedical research. His research informs the field of regenerative medicine and may potentially lead to treatments for muscle disease in the unborn fetus or in the adult patient.
We discovered that it attaches to a previously unstudied receptor on the heart muscle cells, and this binding takes the cells back to a slightly less mature state — closer to that of the embryo — and releases signals that may, among other things, initiate cell division
The team has now begun pre-clinical studies on larger animals in Germany, in cooperation with the Technical University of Munich.
The World Health Organization says heart disease is the top cause of death globally. In 2015 an estimated 17.7 million people died from cardiovascular ailments — 31 percent of total worldwide deaths.