Engineered gut bacteria protect mice against obesity, improve liver function

The gut microbiome--the collection of microorganisms that colonize the gut--is essential for healthy functioning of the host animal and, importantly, can also be responsible for causing disease. Recently, it has become apparent the gut microbiome can influence obesity and metabolic disorders. Researchers now show that by introducing engineered gut bacteria into mice they can protect them against obesity.

Sean Davies and his team at Vanderbilt University presented the findings at the recent American Physiological Society’s conference Inflammation, Immunity and Cardiovascular Disease.

The group engineered bacteria that produced a small lipid known to suppress appetite and lower inflammation. This lipid molecule found localized to the small intestines is typically produced at lower amounts in people with obesity; by restoring these levels, they believed they could prevent obesity and its associated inflammation.

They previously harnessed the engineered bacterium by introducing it into the drinking water of laboratory mice. They then fed these mice, along with a water-only control group, high fats diets and observed less body weight and body fat in the group that received the protective bacteria. 

“We have previously shown that this approach with engineered bacteria could inhibit obesity when standard mice were fed a high-fat diet,” Davies said in a release. “Our new studies focused on mice highly prone to develop atherosclerosis and fatty liver disease, and we showed that the engineered bacteria were beneficial not only in inhibiting obesity, but also in protecting against fatty liver disease and somewhat against atherosclerosis.”

For the new studies, they gave the water-containing bacteria to a group of mice bred to have increased susceptibility to develop atherosclerosis and fatty liver disease. In the bacteria-treated group, they observed less liver fat, reduced markers of liver fibrosis and a slight downward trend of atherosclerotic plaque formation.

“Some day in the future, it might be possible to treat the worst effects of obesity simply by administering these bacteria,” Davies said. “Because of the sustainability of gut bacteria, this treatment would not need to be every day.”