Research in mice links mom’s gut microbes to her baby’s sensory connections
New findings in mice suggest yet another role for gut microbes, even before birth.The new results point to the influence of specific microbes and the small molecules they produce, called metabolites.
“Metabolites from the microbiome of the mother can influence the developing brain of the fetus,” says Cathryn Nagler, an immunologist at the University of Chicago who was not involved with the study. The metabolites do this by reaching a developing pup’s brain where they affect the growth of axons, she says. Axons are the threadlike signal-transmitters of nerve cells.
Vuong and her team looked at the brains of fetuses from pregnant mice — some with their usual gut bugs, some raised without microbes and others ridded of their gut bacteria with antibiotics. When a mother’s microbes were missing, fetuses had shorter and fewer axons extending from the brain’s “relay station” to the cortex, Vuong says. These connections are important for processing sensory information.
Those brain differences appear to have consequences for mice later in life. As adults, mice born to microbe-deficient mothers were less sensitive to touch than mice from mothers with a typical microbiome. For instance, in one of several sensory tests, mice from microbe-deficient mothers took longer to notice a small piece of tape stuck to one of their paws. But when microbe-lacking females were given Clostridia bacteria, their offspring’s brain and behavior developed normally.
