Could the “love hormone” treat obesity and postnatal depression?

MONDAY, July 8, 2024 (HealthDay News) — Researchers have identified a gene whose absence or damage can trigger obesity, behavioral problems and postnatal depression.

The discovery could lead to new treatments for postnatal depression and binge eating: The study on mice suggests that the so-called “love hormone” oxytocin could alleviate the symptoms.

Obesity and postnatal depression are major health problems worldwide.

The new study, published on July 2 in the journal cellis the result of research by scientists at Baylor College of Medicine in Houston and the University of Cambridge in the UK

They studied two boys from different families who were severely obese. The boys suffered from autism, anxiety and behavioral problems triggered by smells or sounds. Both were missing a gene called TRP5.

They inherited the gene deletion from their mothers, who also lacked the gene. Both women were obese and suffered from postnatal depression.

To find out whether the missing TRPC5 gene caused problems in the boys and their mothers, the researchers used genetic engineering. They bred mice with a defective version of the gene – called Trpc5 in mice.

“What we saw in these mice was quite remarkable,” said study co-author Dr. Yong Xu, deputy director for basic sciences at the USDA/ARS Children’s Research Center at Baylor College of Medicine in Houston. “They exhibited behaviors very similar to humans who lack the TRPC5 gene.”

Among mothers, these included signs of depression and difficulties in caring for their babies, he said.

Male mice with the defective gene showed similar problems as the males – weight gain, aggressive behavior, anxiety and an aversion to social interactions.

This shows, says Xu, that this behavior is caused by the gene.

The researchers described TRPC5 as part of a family of genes involved in the perception of sensory signals such as heat, taste and touch. It acts on a pathway in a brain region known to control appetite.

By looking more closely at this region of the brain – the hypothalamus – the researchers found that TRPC5 acts on nerve cells that produce the hormone oxytocin. It is commonly referred to as the “love hormone” because its release is associated with the expression of affection, connection and feelings.

When researchers deleted the gene from these oxytocin neurons, otherwise healthy mice became anxious, overate, and were less social. Mouse mothers showed signs of postpartum depression.

After the gene was restored, body weight decreased and anxiety and depression subsided.

“There is a reason why people who lack TRPC5 develop all these diseases,” said Sadaf Farooqi of the Institute of Metabolic Science at the University of Cambridge, co-author of the study.

Researchers have long known that the hypothalamus plays a major role in regulating instinctive behaviors essential for survival, such as foraging, the fight-or-flight response, and caring for babies.

“Our work shows that TRPC5 acts on oxytocin neurons in the hypothalamus and plays a crucial role in regulating our instincts,” Farooqi said in a Cambridge press release.

Deletions of the TRPC5 gene are rare. DNA samples from half a million people in the UK Biobank showed that 369 of them carried variants of the gene and were overweight. Three quarters of them were women.

The findings suggest that restoring oxytocin levels could help treat people with missing or defective TRPC5 genes, including mothers suffering from postpartum depression, researchers say. However, results in animal studies often differ from those in humans.

“Although some genetic conditions like TRPC5 deficiency are very rare, they teach us important things about how the body works,” Farooqi said. “In this case, we have made a breakthrough in understanding postnatal depression, a serious health problem about which very little is known despite decades of research. And more importantly, it may point to oxytocin as a potential treatment for some mothers with this condition.”

Research suggests that many behaviors that people believe they can control have biological causes.

“We need to show more understanding and compassion towards people suffering from these diseases,” Farooqi noted.

More information

The March of Dimes reports in more detail on postpartum depression.

SOURCE: University of Cambridge, press release, July 2, 2024