Antibiotics and Obesity

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Intestinal bacteria are essential to human health. These little gut bugs help digest food, regulate the absorption of nutrients, and fight off infections. But this complex set of microbes — or microbiome — is also vulnerable: antibiotics and stomach illnesses can wipe out colonies of beneficial bacteria that live inside us.

Scientists are trying to better understand how our body interacts with the microbiome and how changes caused by antibiotics might lead to a variety of health problems. In this effort, researchers at NYU New York recently found that low-dose penicillin given to infant mice led the mice to develop obesity as they matured.

What is perhaps more significant is that obesity persisted in the mice even when the microbiome returned to normal. This leads the researchers to believe that there is a "developmental window," during which changes to gut bacteria have long-term effects on mice. The results were published in the journal Cell.

Jorge Zárate (NYU Abu Dhabi Class of 2014) conducted research for the paper at the lab of Doctor Martin Blaser in New York. He and the researchers were trying to "understand how changes in the microbiome — be it due to diet, exposure to antibiotics, or both — altered the mice," Zarate said.

While in New York, Zárate investigated the way antibiotics denigrated colonies of bacteria. When he returned to Abu Dhabi, he was able to analyze liver cells from the mice using microscopes, looking for the development of fatty cells in the liver, which are signs of damage and inflammation.

"We found that mice that became obese following disruption to their microbiome by antibiotics did not become lean again after the antibiotics ceased," Zárate said. "This is relevant when we think about how antibiotics might affect humans."

Zárate cautions that this research does not indicate that humans respond to antibiotics in the same way that mice do. But future experiments may help scientists better understand the effects antibiotics have on bacteria that are so important to human health.

Zárate is currently pursuing a degree in medicine at Washington University in St. Louis.

Doctor Martin Blaser discusses the conflicted relationship humans have with antibiotics (The Guardian)