SAN DIEGO Pregnant women may transmit the damaging effects of stress to their unborn child by way of the bacteria in their vagina and through the placenta, suggest new findings from two animal studies presented by researchers at the University of Pennsylvania at Neuroscience 2013, the annual meeting of the Society for Neuroscience.
Stresses felt by mothers during pregnancy have been shown to affect offspring neurodevelopment and increase the risk for disorders such as autism and schizophrenia, but the mechanisms by which it can reprogram the developing brain are not clear.
As a newborn passes through the birth canal, the microbiome of a mother's vagina ends up in the offspring's gut. In the first study, the team, led by Tracy L. Bale, PhD, Professor of Neuroscience in the Perelman School of Medicine, Department of Psychiatry and the School of Veterinary Medicine Department of Animal Biology at Penn, found that changes in the microbiome produced by stress in pregnant mice altered the microbe population in the newborn's gut and correlated to changes in the developing brain.
Using targeted approaches in mice, the researchers determined that early prenatal stress affected both the maternal and offspring levels of lactobacillus, a lactic acid-producing bacteria associated with brain neurochemistry. It has been demonstrated that throwing off those levels can affect neurodevelopment.
The team then observed changes in gene expression in the hypothalamus in offspring of the mice that correlated with levels of lactobacillus. Many of these genes play a critical role in development and brain function.
"For the first time, we've shown how stress can change the microbiome in the vagina and impact the microbiome of her offspring's gut, and that may, in part, ultimately affect their brain function and neurodevelopment," said Bale. "This mechanism could help us better understand how it may predispose individuals to neurodevelopmenta
|Contact: Steve Graff|
University of Pennsylvania School of Medicine