Gut microbiota influences blood-brain barrier permeability

A new study in mice, conducted by researchers at Sweden’s Karolinska Institutet together with colleagues in Singapore and the United States, shows that our natural gut-residing microbes can influence the integrity of the blood-brain barrier, which protects the brain from harmful substances in the blood. According to the authors, the findings provide experimental evidence that our indigenous microbes contribute to the mechanism that closes the blood-brain barrier before birth. The results also support previous observations that gut microbiota can impact brain development and function.

“We showed that the presence of the maternal gut microbiota during late pregnancy blocked the passage of labeled antibodies from the circulation into the brain parenchyma of the growing fetus”, says first author Dr. Viorica Braniste at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet. ”In contrast, in age-matched fetuses from germ-free mothers, these labeled antibodies easily crossed the blood-brain barrier and was detected within the brain parenchyma.”

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