High fat diet accelerates Barrett esophageal carcinogenesis by inducing a distinct IL-8 dependent immune reaction through alteration of the microbiome

Barrett Esophagus (BE) is a risk factor for the development of esophageal adenocarcinoma (EAC). As endemic obesity emerges as a risk factor for increasing numbers of EAC we utilized our IL-1b mouse model of BE to understand the impact of a high fat diet (HFD) on disease progression. Indeed, increased dysplasia development in HFD treated IL-1b mice correlated with an accelerated cytokine response with specific upregulation of IL-8 in esophageal tissue, which could be confirmed by specific overexpression of IL-8 in the BE mouse model. Consequently we observed an influx of immature myeloid cells and neutrophils resulting in a decrease of regulatory NK T cells. HFD led to a specific shift in the gut microbiome, similar to that in human BE patients, being responsible for a specific inflammatory phenotype with elevated IL-1b and IL-8 which could be eliminated under germ free conditions and lead to an increased influx of cardia (Lgr5) stem cells into the esophagus giving rise to dysplasia. Our mouse model of BE in which overexpression of IL-1b in the squamous esophagus induces chronic inflammation leads to metaplasia and dysplasia at the squamo-columnar junction (SCJ) in the mouse gastro-esophageal junction resembles the human disease. The impact of a high fat diet (HFD) and corresponding increase of specific upregulation of IL-8 in esophageal tissue on disease progression was investigated by comparing the gene expression profiles of mice overexpressing IL-1b and IL-8 and mice overexpressing IL-1b being fed with HFD or chow diet.