ABSTRACT
OBJECTIVE: To review the understanding of the pathogenesis of eosinophilic esophagitis (EoE) and the role of the immune system in the disease process. DATA SOURCES: Peer-reviewed articles on EoE from PubMed searching for "Eosinophilic Esophagitis and fibrosis" in the period of 1995 to 2013. STUDY SELECTIONS: Studies on the clinical and immunologic features, pathogenesis, and management of EoE. RESULTS: Recent work has revealed that thymic stromal lymphopoietin and basophil have an increased role in the pathogenesis of disease. Additional understanding on the role of fibrosis in EoE is emerging. CONCLUSION: The incidence of EoE is increasing like most atopic disease. Similar to other allergic diseases, EoE is treated with topical steroids and/or allergen avoidance.
Subject(s)
Eosinophilic Esophagitis/immunology , Esophagus/immunology , Esophagus/pathology , Adrenal Cortex Hormones/therapeutic use , Adult , Allergens/immunology , Basophils/immunology , Child , Cytokines/metabolism , Eosinophilic Esophagitis/drug therapy , Eosinophilic Esophagitis/epidemiology , Eosinophils/cytology , Female , Genetic Predisposition to Disease , Humans , Lymphocytes/immunology , Male , Thymic Stromal LymphopoietinABSTRACT
BACKGROUND: Esophageal fibrosis is a complication of eosinophilic esophagitis (EoE) which has been attributed to both subepithelial fibrosis and to epithelial to mesenchymal transition (EMT), a process by which epithelial cells acquire mesenchymal features. Common to both causes of EoE-fibrosis is the notion that granulocyte-derived TGF-ß, induces myofibroblast differentiation of the target cell. To date, the role of esophageal epithelial cells as effector cells in esophageal fibrosis has never been explored. Herein, we investigated consequences of cross-talk between esophageal epithelial cells and fibroblasts, and identified profibrotic cytokines which influence the development of EMT in vitro. METHODS AND RESULTS: Stimulation of primary fetal esophageal fibroblasts (FEF3) with conditioned media (CEM) from esophageal epithelial cells (EPC2-hTERT), primed FEF3 cells to secrete IL-1ß and TNFα, but not TGFß. To determine whether these cytokines signaled in a paracrine fashion to esophageal epithelial cells, FEF3 cells were stimulated with CEM, followed by transfer of this fibroblast conditioned media (FCM) to EPC2-hTERT cells. Epithelial FCM stimulation increased expression of mesenchymal markers and reduced E-cadherin expression, features of EMT which were TNFα and IL-1ß-dependent. Using organotypic culture models, primary EoE epithelial cells exhibited features of EMT compared to non-EoE cells, corresponding to patterns of EMT in native biopsies. CONCLUSIONS: Esophageal epithelial cell and fibroblast cross-talk contributes to esophageal fibrosis. Our results suggest that features of EMT can develop independent of TGF-ß and granulocytes, which may have important implications in treatment of EoE.
