Microbes in our intestines, and part of our immune system that regulates, might be partly responsible for the metabolic syndrome, a set of metabolic disorders linked to obesity that increase the risk of diabetes and cardiovascular disease according to a new study in mice. This work draws on recent discoveries that have established a link between the composition of gut flora and obesity. The study of Matam Vijay-Kumar, of the University At Emory Atlanta And his colleagues suggests that the innate immune system that defends the body against pathogens, could be the link between gut microbiota and metabolism.

The authors found that mice lacking an important component of the innate immune system protein called TLR5, have developed features of metabolic syndrome as a gain in fat and insulin resistance with a change in the intestinal microbiota . The mutant mice also ate more than others. The transfer of intestinal bacteria in mice mutant mice did not initially intestinal flora that these have developed several features of the metabolic syndrome, suggesting that the microbial change was probably a cause rather than a consequence , the onset of the disease. The authors also sequenced a portion of genetic material from microbes in the intestinal flora and mutant mice have identified a set of unusually abundant bacterial species. The researchers suggest that deficiencies in the innate immune system may cause changes in the intestinal microbiota, which then induce an inflammatory signal low noise. This in turn could influence the signal via the insulin receptor, increase appetite and lead eventually to other aspects of the metabolic syndrome.