A high-fat diet during pregnancy generates an overconsumption of serotonin and consequent depressive behaviors in male newborns.
While on the one hand being or becoming overweight during pregnancy can pose potential health risks for mothers, on the other hand, there are indications that highlight the possibility of developing psychiatric disorders such as autism or depression, which often affect a gender more than the other. However, it is not yet understood how the accumulation of adipose tissue in the mother can transmit signals across the placenta in a sex-specific way and reorganize the brain of the developing offspring.
To fill this gap, researchers at Duke University studied pregnant mice fed a high-fat diet. They found that the mother’s high-fat diet triggers the brain’s developing immune cells to overuse serotonin , a chemical that affects the brain’s mood, causing depression-like behavior. been recorded only in male mouse pups , but not in the brains of female mice. According to the researchers, a similar phenomenon could also occur in humans. People with mood disorders, such as depression, often lose interest in pleasurable activities. For rats, an innately pleasurable activity is drinking sugar water.
Differences between males and females
Alexis Ceasrine, one of the researchers, measured their preference for the drink as an estimate of depression. Males, but not females, born to mothers on a high-fat diet, no longer showed interest in fresh water. This has been termed by scientists as a depressive behavior.
Ceasrine and his team found that depressed male mice had less serotonin in their brains, both in the womb and as adults, suggesting that these early deficits have lifelong consequences.
To test whether this might also be true for humans, Ceasrine collaborated with Susan Murphy, a professor of obstetrics and gynecology at Duke School of Medicine, who provided placental and fetal brain tissue from a previous study. Just as the researchers observed in mice, they found that the more fat measured in human placental tissue, the less serotonin was detected in the brains of males — but not females.
For now, this research highlights that not all placentas are created equally and that this diversity is also based on the gender of the unborn child. This work may one day help doctors and parents better understand and treat or prevent the origins of some mood disorders by considering early environmental factors, such as fat accumulation during pregnancy.
- Maternal diet disrupts the placenta–brain axis in a sex-specific manner. (nature.com)