Straight from the gut: Microbes can cause obesity

Obesity and chronic liver disease can be triggered by a family of proteins that alter populations of microbes in the stomach, a discovery that suggests the condition may be infectious, Yale scientists report. The study, in the advance online publication of Nature , expands on earlier Yale research that showed how similar microbial imbalances caused by the same family of proteins increases the risk of intestinal diseases such as colitis. The Yale scientists' most extraordinary finding, they said, was that the altered intestinal environment that led to obesity and liver disease was infectious among the community of mice. "When healthy mice were co-housed with mice that had altered gut microbes, the healthy mice also developed a susceptibility for development of liver disease and obesity," said senior author Richard A. Flavell, professor of immunobiology at Yale School of Medicine and a Howard Hughes Medical Institute investigator. The proteins in question are called inflammasomes. They are responsible for launching the immune system's inflammatory response. Inflammasomes act as sensors and regulators of the microbial environment of the intestines.