Penicillin and related medicines, like ampicillin and amoxicillin, are the most used antibiotics in children worldwide. In the United States, the average child gets nearly three prescriptions for antibiotics before they turn two.
But that exposure early in life could alter human brain development in areas responsible for cognitive and emotional functions, according to a Rutgers study.
The study suggests that penicillin affects not only the microbiome — the trillions of beneficial microorganisms that live in and on our bodies — but also gene expression, which allows cells to respond to their changing environment, in key areas of the brain.
“Our previous work has shown that exposing young animals to antibiotics changes their metabolism and immunity. The third important development in early life involves the brain. This study is preliminary but shows a correlation between altering the microbiome and changes in the brain that should be further explored,” said lead author Martin Blaser, director of the Center for Advanced Biotechnology and Medicine at Rutgers.
The study compared mice that were exposed to low dose penicillin in utero or immediately after birth to those that were not exposed.
The mice given penicillin experienced substantial changes in their intestinal microbiota and had altered gene expression in the frontal cortex — the area in the brain responsible for memory development — and the amygdala, which is involved with the processing of emotions.
“Early life is a critical period for neurodevelopment,” Blaser said. “In recent decades, there has been a rise in the incidence of childhood neurodevelopmental disorders, including autism spectrum disorder, attention deficit/hyperactivity disorder and learning disabilities. Although increased awareness and diagnosis are likely contributing factors, disruptions in cerebral gene expression early in development also could be responsible.”
The researchers acknowledge more studies are needed to determine whether antibiotics directly affect brain development or if molecules from the microbiome travel to the brain and disturb gene activity and cause cognitive deficits. The study was published in the journal iScience.
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