Is stress passed down from mother to daughter?
What mechanisms make mice, who were subjected to maternal stress in utero, develop anxiety/depressive disorders as adults?
That’s the question an American team, whose work on female mice was published in the journal "Brain, Behavior and Immunity", wanted to answer, The researchers made several observations in adult mice:
- Stress leads to intestinal dysbiosis associated with these disorders;
- Changes in the intestinal microbiota are associated with the production of cytokines.
- Stress causes the release of cytokines, which impact certain neuronal growth factors that are essential to brain development.
Their experiments on pregnant mice showed an increased level of cytokines in the placenta and in the brains of newborn baby mice born to stressed mothers. Conversely, they revealed a drop in neuronal growth factors in the placenta and a specific structure in the brain in these mice as adults. This discovery suggests that in utero stress has a lasting impact on neurological development. Furthermore, once they were adults, the mice that were subject to prenatal stress were demonstrably more anxious and stressed than others, and they had intestinal dysbiosis similar to their mothers. According to the authors, the transfer of anxiety can be explained in part by the inheritance, through the gut-brain axis, of maternal microbes that belonged to the placental microbiota.
Tamar L. Gur et al. Prenatal stress affects placental cytokines and neurotrophins, commensal microbes, and anxiety-like behavior in adult female offspring. Brain Behav Immun. 2017 Aug;64:50-58. doi: 10.1016/j.bbi.2016.12.021.