Key Points:
- A new study shows the neurohormone oxytocin can help stem cells develop into cardiomyocytes, muscle cells that generate heart contractions.
- Take clues from zebrafish, the researchers demonstrated the effect oxytocin can have on human tissue in vitro.
- This discovery could one day be used to promote the regeneration of the human heart after a heart attack.
Oxytocin is to blame when you get those happy feelings from doing something enjoyable, like exercise or reading. The neurohoromone has many different and varied functions in humans and now, researchers from Michigan State University have revealed a new, albeit surprising one, with implications for future heart health.
In a study published in Frontiers in Cell and Developmental Biology, researchers demonstrate that oxytocin stimulates stem cells derived from the heart’s outer layer (epicardium) to migrate into its middle layer (myocardium), and there develop into cardiomyocytes—muscle cells that generate heart contractions. This discovery could one day be used to promote the regeneration of the human heart after a heart attack.
Cardiomyocetes typically die off in great numbers after a heart attack and, because they are highly specialized cells, they can’t replenish themselves. Previous studies have shown that a subset of cells in the epicardium can undergo reprogramming to become stem-like cells, called Epicardium-derived Progenitor Cells (EpiPCs), which can regenerate not only cardiomyocytes, but also other types of heart cells. However, the production of EpiPCs is inefficient for heart regeneration in humans under natural conditions—something that is not true for zebrafish.
Zebrafish can regrow their heart when as much as a quarter of it has been lost. This is done partly by proliferation of cardiomyocytes, but also by EpiPCs.
In the new study, the researchers showed that oxytocin has a similar effect on human tissue in vitro. Oxytocin—but none of 14 other neurohormones tested—stimulated cultures of human-Induced Pluripotent Stem Cells (hIPSCs) to become EpiPCs, at up to twice the basal rate. That is a much stronger effect than other molecules previously shown to stimulate EpiPC production in mice. Conversely, genetic knock-down of the oxytocin receptor prevented the regenerative activation of human EpiPCs in culture.
“These results show that it is likely that the stimulation by oxytocin of EpiPC production is evolutionary conserved in humans to a significant extent,” said senior study author Aitor Aguirre, assistant professor at Michigan State University. “Oxytocin is widely used in the clinic for other reasons, so repurposing for patients after heart damage is not a long stretch of the imagination. Even if heart regeneration is only partial, the benefits for patients could be enormous.”
Aguirre said he and his team will look at oxytocin in humans after cardiac injury next.
Information provided by Frontiers.