Study Links Prenatal Stress to Adult Anxiety in Mice
Feel anxious frequently? New research suggests that the origins of that anxiety could trace back to your mother’s experiences even before you were born. This finding comes from a study conducted by scientists at Weill Cornell Medicine in the United States.
The study reveals that infections or stress experienced by a mother during pregnancy may heighten the likelihood of her offspring facing anxiety issues as adults. Earlier studies had identified connections between prenatal health problems and later mental health conditions, including anxiety, but this new research digs deeper into the neurological factors at play.
The research team genetically modified mice to mirror the increased inflammation that a pregnant mother might encounter under stress. They observed the behavior of the resulting offspring closely.
Focusing specifically on male mice—who typically exhibit more pronounced anxiety behaviors than females—the researchers found these animals were genetically normal. Remarkably, even without inheriting stress-related traits from their mothers, these mice showed signs of anxiety as adults, such as a tendency to avoid open spaces. Scans revealed that a specific group of brain cells in the ventral dentate gyrus (vDG) was particularly active when the animals felt threatened.
“Our data suggests that prenatal difficulties can create lasting changes in the vDG neurons, linking the conditions of gestation to anxiety-like behaviors,” explains neuropharmacologist Miklos Toth.
“This could shed light on why some people remain sensitive to stress and exhibit avoidance behaviors related to inherent anxiety.”
The team also explored DNA methylation in the mice’s brains, which is a tagging process that determines whether certain genes are active or dormant. They found modifications at numerous locations along the DNA in the vDG, particularly in areas related to neuron communication.
Interestingly, the areas that were reprogrammed exhibited heightened activity when the mice perceived threats. It appears the brains of these mice are wired to be more anxious about potential dangers, often even before any real threat presents itself.
“Overall, these epigenetic changes seem to be prompting neurons in the vDG to respond in a unique way in adulthood when the environment feels unsafe,” notes neuropharmacologist Kristen Pleil.
“The increased activity in these neurons can lead the mice to see their surroundings as more threatening than they actually are.”
Anxiety is among the most prevalent mental health issues, affecting nearly a third of people at some point in their lives. Scientists continue to investigate various contributing factors and potential treatments for anxiety.
While this research has only been conducted in mice so far, it highlights how early life experiences could influence anxiety risk later on. This might even lead to new diagnostic methods and potentially some treatment options.
It also serves as a reminder of the importance of a healthy pregnancy. The researchers aim to delve further into the mechanism they’ve discovered, especially why only a select group of neurons are impacted by prenatal stress.
“A mouse has nearly 400,000 cells in the vDG, but just a few thousand are affected during pregnancy,” Toth remarks. “Next, we really want to understand why these particular cells are programmed epigenetically.”
The findings are published in Cell Reports.
