Yeast in the gut boosts levels of uric acid, which damages the intestinal wall and worsens bowel inflammation in mice.

Credit: Thomas Deerinck, NCMIR/SPL

Gut bacteria are known to influence intestinal disease, but the role of gut fungi — such as the yeast Saccharomyces cerevisiae (pictured) has not been well studied. June Round and her colleagues at the University of Utah in Salt Lake City fed mice with S. cerevisiae, then chemically induced gut inflammation, or colitis. Mice that were given the yeast produced more uric acid and had more gut inflammation than untreated animals did. The team found that the yeast increased the intestinal wall's degradation of molecules called purines, leading to higher uric acid levels. Treating the animals with allopurinol, an inhibitor of purine metabolism, eased the colitis.

In serum samples from healthy humans, elevated uric acid levels correlated with greater numbers of antibodies against S. cerevisiae. This yeast might play a part in human inflammatory bowel disease, the authors suggest.

Sci. Transl. Med. 9, eaaf9044 (2017)