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Researchers say a so-called “love hormone” in our body may have heart-healing properties. Anfisa & Friends/Stocksy
  • Researchers say the neurohormone oxytocin, also known as the “love hormone,” may be capable of healing damaged heart muscles.
  • The researchers used zebrafish, well known for their ability to reproduce organs, in their study to look at oxytocin’s healing potential.
  • Experts note that more study is needed as there can be side effects in using oxytocin as a healing agent.

Oxytocin is a neurohormone called the “love hormone” because it promotes social bonds and generates pleasurable feelings.

It also regulates lactation, uterine contractions, the movement of sperm, and testosterone production.

Now, a new study suggests that the hormone might someday help regenerate damaged heart muscles.

The researchers said that previous research has concluded that the epicardium, a membrane found in the layers of the heart, can partially regenerate injured heart cells. In mammals, however, this process doesn’t work independently but might if cells are reprogrammed.

Researchers noted that zebrafish produced oxytocin after their hearts were injured by extreme cold, leading to a response that promotes heart regeneration.

“The heart possesses a population of cells, called epicardial cells, that reside in its outer layers,” said Aitor Aguirre, Ph.D., one of the authors of the study and an assistant professor of biomedical engineering at the Institute for Quantitative Health Science and Engineering at Michigan State University.

“After a massive cardiac injury, such as a heart attack, epicardial cells become epicardial stem cells and can then regenerate muscle, blood vessels, and other cardiac tissues, but their numbers are far too small for any long-lasting impact,” he told Healthline.

“What we have found in this study is that oxytocin induces the formation of these stem cells and promotes their expansion, increasing their efficiency in heart regeneration,” Aguirre added. “It is interesting because this demonstrates that the brain controls some regeneration, so there could be factors in addition to the oxytocin that promotes regeneration.”

He noted that “the most common role of oxytocin relates to bonding and pleasure, which suggests that being in a caring and loving environment might promote heart healing. You could say that the love hormone fixes broken hearts.”

Zebrafish are known for their ability to regenerate cells throughout their body.

Past research has reported that these fish can regenerate organs, including the retina, spinal cord, parts of the brain, and certain internal organs. Experts say this makes them a good resource for studying this concept.

The researchers conducting the current study reported that within three days of the heart injury, the Zebrafish increased the expression of oxytocin in the brain by about 18-fold.

The oxytocin then traveled to the epicardium, which bound to the oxytocin receptor, triggering cells to develop new cells. These cells migrated to the myocardium and developed into cardiomyocytes, blood vessels, and other heart cells, replacing the injured ones.

Oxytocin had a similar effect on human cells in a laboratory. The scientists tested 15 neurohormones and they said oxytocin had the strongest effect on stimulating the regeneration of human cells.

Oxytocin is currently used during labor and delivery. It is used to begin or speed up contractions during labor and typically takes effect about 30 minutes after injection. It can also help to reduce bleeding after birth.

The risk of using oxytocin during labor is overstimulation of the uterus and causes it to contract too often, according to the American College of Obstetrics and Gynecology. This may lead to changes in the fetal heart rate.

While there are benefits to using oxytocin during labor and delivery, there are also risks. These risks and benefits will need to be considered as researchers look at the hormone’s potential use for stimulating heart regeneration.

“Oxytocin, or a similar analog that stimulates its receptor, could conceivably be utilized to regenerate the heart in humans after acute or chronic injury,” said Dr. Rigved Tadwalkar, a cardiologist at Providence Saint John’s Health Center in California.

“The current study reveals the beneficial effects of oxytocin in zebrafish in vivo and on human tissue in vitro,” Tadwalkar told Healthline. “The findings suggest that the pathway involved in stimulating stem-like cells to the myocardium is preserved in humans, at least to a degree.”

“Unfortunately, oxytocin has a short half-life, meaning that it exists only briefly in human circulation,” Tadwalkar added. “However, we could take advantage of this beneficial signaling pathway in humans by creating drugs that are higher in potency or with longer half-lives.”

“Since we already use oxytocin clinically, this is not inconceivable,” he noted. “Even if the effects are limited, the benefit would be splendid in this population. For example, if oxytocin is shown to only have a preventative role, as opposed to a regenerative one, this would still be welcome, as to avert subsequent damage to the heart.”