Oxytocin helps humans bond with loved ones and can be triggered through physical contact, music, and exercise. It is a hormone synthesized in the brain and distributed throughout the body by the pituitary gland. Its primary purpose is to support childbirth, which is why it is sometimes known as the "love medication" or "love hormone."
Throughout zebrafish and human cell culture systems, scientists from Michigan State University observed that oxytocin activates stem cells obtained from the heart's outermost surface (epicardium) to transfer into the heart's middle layer (myocardium) and improve into cardiomyocytes, muscle cells that initiate heart contractions.
The research would someday boost cardiac regeneration after a cardiac event. The observations were reported in the journal Frontiers in Cell and Developmental Biology.
Oxytocin Benefits
Also referred to as neurohormone, oxytocin is well-known for enhancing social relationships and eliciting pleasure experiences, such as art, exercise, or sex. Moreover, the hormone serves several other activities, including female breastfeeding and uterine contraction modulation and male ejaculation, sperm transport, and testosterone production modulation.
A Harvard University report states that oxytocin promotes uterine muscle spasms while also increasing the creation of prostaglandins, which promote uterine contractions. Women taking too long are frequently administered oxytocin to accelerate the process. As soon as a baby is born, oxytocin helps to transfer milk from the ducts in the breast to the nipple and fosters a connection between mom and baby.
"In this we prove that oxytocin, a neuropeptide also recognized as the love hormone, is capable of stimulating heart repair mechanisms in injured hearts in zebrafish and human cell cultures, opening the door to new potential therapies for heart regeneration in humans," said Dr. Aitor Aguirre, senior author of the study and an assistant professor at Michigan State University's Department of Biomedical Engineering.
Obtained Stem cell-like Replenishing Cardiomyocytes
After a cardiac arrest, cardiomyocytes normally die in significant masses. They can't regenerate themselves since they're highly technical cells. Prior research suggests that a portion of epicardium cells may be reprogrammed to produce stem-like cells classified as Epicardium-derived Progenitor Cells (EpiPCs), which might regenerate not just cardiomyocytes as well as other types of cardiac cells.
"Think of such EpiPCs as the stonemasons who renovated churches in Europe throughout the Middle Ages," Aguirre remarked. Regrettably, under naturalistic settings, the creation of EpiPCs is ineffective for human heart regeneration.
The zebrafish is recognized for its exceptional ability to repair organs such as the brain, retina, internal organs, skeleton, and skin. They don't have heart attacks, but their numerous attackers are eager to take a piece out of any organ, including the heart; therefore, zebrafish can rebuild their heart after losing up to a quarter of it. These are accomplished in part by cardiomyocyte proliferation but also through EpiPCs. But how do zebrafish EpiPCs mend the heart so efficiently? Can we discover a "magic bullet" in zebrafish to artificially stimulate the creation of EpiPCs in humans?" Aguirre explained.
Having obtained that result, the scientists have found that in zebrafish, three days after cryoinjury (heart injury caused by freezing), the production of the oxytocin messenger RNA rises 20-fold in the brain. Scientists also discovered that oxytocin gets to the zebrafish epicardium and latches to the oxytocin receptor, activating a biochemical cascade that promotes specific cells to enlarge and evolve into EpiPCs. Those new EpiPCs subsequently travel to the zebrafish myocardial, where they mature into cardiomyocytes, blood vessels, and other vital heart cells to replenish those that have died.
Oxytocin, molecular model. Mammalian hormone acts as a neuromodulator in the brain. Atoms are represented as spheres and are color-coded: carbon (grey), hydrogen (white), nitrogen (blue), oxygen (red), and sulfur (yellow).
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The Same Impact on the Culture of Human Tissue
Importantly, the results demonstrate that oxytocin had a comparable influence on people's tissue in vitro (biological process). Oxytocin, but not the other 14 neurohormones studied here, drives human Induced Pluripotent Stem Cells (hIPSCs) cultures to become EpiPCs at up to double the normal rate: a far larger impact than other compounds proven in the past to induce EpiPC formation in rodents.
In contrast, genetic knock-down of the oxytocin receptor inhibited the regenerative activation of human EpiPCs in culture. The scientists also discovered that the link connecting oxytocin and EpiPC activation is the essential "TGF- signaling pathway," known to govern cell proliferation, maturation, and movement.
"Such findings indicate that oxytocin stimulation of EpiPC production is likely to be evolutionarily preserved in humans to a considerable degree," Aguirre stated. "Oxytocin is widely used in the clinic for other reasons, so repurposing it for patients after heart damage would not be a long stretch of the imagination. Though if heart regeneration is only partial, the benefits for patients might be enormous."
"Next, we need to study oxytocin in people following cardiac damage. Because oxytocin is short-lived in circulation, its benefits in humans may be hampered. Drugs particularly formulated with a prolonged half-life or higher potency may be effective in this scenario," Aguirre suggested.
Synthetic (made) versions of oxytocin, such as Syntocinon and Pitocin, are used by healthcare practitioners to deliver babies if someone hasn't started spontaneously or to intensify contractions. According to Cleveland Clinic, healthcare practitioners also use synthetic oxytocin to hasten placental discharge (the third stage of labor) and lessen the risk of excessive bleeding (postpartum hemorrhage).
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