Dietary phosphate exacerbates intestinal inflammation in experimental colitis

Abstract

The recent widespread consumption of Western diets and food additives worldwide is associated with excessive inorganic phos phate intake. However, researchers have known little about the impact of dietary phosphate intake on the development of inflammatory bowel disease to date. In this study, we investi gated the effects of dietary phosphate on intestinal inflammation in experimental colitis. SpragueDawley rats were fed different phosphate diets (0.5%, 1.0% and 1.5% phosphate) with or with out dextran sulfate sodium. For in vitro study, the effects of phos phate on proinflammatory cytokine induction and reactive oxygen species production in RAW264.7 macrophage were examined. Dietary phosphate exacerbated intestinal inflammation in experi mental colitis in a dosedependent manner, as assessed by the clinical disease activity score, colon length, and histology. Further more, the high phosphate diet increased myeloperoxidase activity and proinflammatory cytokine mRNA expression through the activation of nuclear factor ?B in the inflamed colon. In addition, high phosphate loading in RAW264.7 cells directly enhanced reac tive oxygen species production and proinflammatory cytokine gene expression. Our results demonstrated that the high phos phate diet exacerbated intestinal inflammation in experimental colitis. These findings have important therapeutic implications for inflammatory bowel disease patients.