Using a two-pronged strategy, gut microbes first break down otherwise indigestible dietary components, effectively increasing the amount of calories we can harvest; then they promote fat storage from the harvested calories.

The research team found that the gut microbes promote fat storage by suppressing the gut's production of a protein called fasting-induced adipocyte factor (Fiaf). Fiaf functions to help keep the gates to fat cells closed.

The findings will be reported in the Nov. 2, 2004 issue of the Proceedings of the National Academy of Sciences and are currently available online.

"Finding that Fiaf is directly manipulated by the gut microbiota is intriguing," says senior author Jeffrey Gordon, M.D. "It raises the possibility that an individual's predisposition to obesity or leanness may be partly determined by the composition of the microbes living in the gut."

Gordon is the Dr. Robert J. Glaser Distinguished University Professor and director of the new Center for Genome Sciences--the Center was launched as part of BioMed 21, the University's initiative for using the latest knowledge of the human genome to develop new ways to diagnose, treat and ultimately prevent a variety of human diseases.

Treatments for obesity that require long-term dietary changes almost always fail. According to Gordon, this research suggests that derivatives of Fiaf could potentially become therapeutic agents.

"We uncovered the importance of Fiaf by studying mice raised without ever being exposed to microorganisms. These so-called germ-free mice eat 30 percent more than normal mice yet have 50 percent less body fat," says Fredrik Bckhed, Ph.D., postdoctoral resea
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Contact: Gwen Ericson
ericsong@wustl.edu
314-286-0141
Washington University School of Medicine
1-Nov-2004