Oxytocin is a hormone produced in the brain known for its ability to generate feelings of pleasure and promote social bonds. Known as the “love hormone”, it also acts in the regulation of the process of breast milk production and uterine contractions in women, as well as regulating ejaculation, sperm transport and testosterone production in men.
Scientists in the United States have found evidence that oxytocin may have one more function, this little known: the regeneration of the heart. Researchers at Michigan State University found that, in zebrafish and human cell cultures, the hormone is able to encourage stem cells derived from the outer layer of the heart to migrate to the middle layer. In the so-called myocardium they develop into muscle cells that generate cardiac contractions, called cardiomyocytes.
According to experts, the discovery could open the way for the development of strategies to promote the regeneration of the human heart after a heart attack. The results of study were published in the scientific journal Frontiers in Cell and Developmental Biology.
“Here we show that oxytocin, a neuropeptide also known as the love hormone, is able to activate cardiac repair mechanisms in injured hearts in zebrafish and human cell cultures, opening the door to potential new therapies for heart regeneration in humans,” said Aitor Aguirre, assistant professor in the Department of Biomedical Engineering at Michigan State University, senior author of the study in a statement.
Cardiomyocytes usually die in large numbers after a heart attack. Because they are highly specialized cells, they cannot remake themselves. Previous studies have shown that a subset of cells in the heart’s outer tissue layer (called the epicardium) can undergo reprogramming to become stem cells, called epicardium-derived progenitor cells, which can regenerate not only cardiomyocytes but other types of heart cells as well. .
“Think of epicardium-derived progenitor cells like the stonemasons repairing cathedrals in Europe in the Middle Ages,” Aguirre said. However, for humans, the production of these cells is inefficient for heart regeneration under natural conditions.
Zebrafish could be a path to understanding how to more efficiently regenerate hearts. They are famous for their great ability to regenerate organs including the brain, retina, internal organs, bones and skin. Recovery of the heart is done in part by the proliferation of cardiomyocytes, but also by progenitor cells.
According to the authors, the key to explaining the ability to repair the heart efficiently may lie in oxytocin. To reach this conclusion, the experts found that in zebrafish, within three days of frostbite injury to the heart, oxytocin messenger RNA expression increases by up to 20-fold in the brain.
The analyzes further showed that this oxytocin travels to the zebrafish epicardium and binds to the oxytocin receptor, triggering a molecular cascade that stimulates local cells to expand and progenitor cells develop. These new cells then migrate into the zebrafish myocardium to develop into cardiomyocytes, blood vessels and other important cardiac cells to replace those that have been lost.
Similar effect in human tissue cultures
Scientists have verified that oxytocin has a similar effect on human tissue in laboratory experiments (in vitro). Oxytocin stimulates human induced pluripotent stem cell cultures to become high-capacity progenitor cells.
The authors also showed that the link between oxytocin and progenitor cell stimulation is an important signaling pathway known to regulate cell growth, differentiation, and migration.
“These results show that oxytocin stimulation of progenitor cell production is likely to be evolutionarily conserved in humans to a significant extent. Oxytocin is widely used in the clinic for other reasons, so repurposing patients after heart damage is not a long stretch of the imagination. Even if heart regeneration is only partial, the benefits for patients can be enormous,” said Aguirre.
The researcher highlights that the next steps include analyzing oxytocin in humans after cardiac injury. “Oxytocin itself is short-lived in circulation, so its effects in humans could be jeopardized by this. Specifically designed drugs with longer half-lives or more potency may be useful in this scenario. Overall, preclinical animal trials and human clinical trials are needed to move forward,” he concluded.
Source: CNN Brasil