Dietary freeze-dried beer prevents inflammation in DSS-induced chronic ulcerative colitis in mice†

Inflammatory bowel disease (IBD) is a complex condition that is influenced by numerous factors, including genetic, immune and environmental factors. In the search for new therapies, nutritional interventions including dietary polyphenols are becoming increasingly important in the management of IBD. The present study aimed to investigate the antioxidant and anti-inflammatory effects of commercial freeze-dried beer, an interesting product resulting from the fermentation of cereals, rich in polyphenols, in (I) an in vitro model of inflammation using lipopolysaccharide (LPS)-stimulated THP-1 human derived macrophages and (II) a murine dextran sodium sulfate (DSS)-induced chronic colitis model, for elucidating the action mechanism involved. According to the results, commercial freeze-dried beer exhibits antioxidant, anti-inflammatory and immunomodulatory properties in LPS-stimulated THP-1 human macrophages by reducing reactive oxygen species (ROS), tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels. Moreover, in vivo results showed that preventive treatment with dietary freeze-dried beer improved murine DSS-induced chronic colitis by attenuation of the clinical and histological signs of colonic damage. Colonic cytokine levels in animals fed with commercial freeze-dried beer reached values near basal levels. In addition, pro-inflammatory cyclooxygenase (COX)-2 and microsomal prostaglandin E synthase (mPGES)-1 protein expressions were significantly downregulated via inhibition of nuclear transcription factor kappa B (NF-κB) translocation. This inhibition may be mediated by an induction of the antioxidant nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway and a reduction of signal transducer and activator of transcription (STAT)-3 phosphorylation orchestrating its potent anti-inflammatory and immunomodulatory effects. Overall, our results suggest that dealcoholized beer may be effective in the management of immune-mediated inflammatory diseases in which macrophages are crucial, including IBD, providing clues for developing useful dietary interventions against inflammation-associated pathologies.