Gene expression and clinical outcomes after dietary treatment for eosinophilic esophagitis: a prospective study.

BACKGROUND: Eosinophilic esophagitis (EoE) is an allergen-mediated disease and elimination diets have proven to be effective to obtain clinical and histological remission. However, the effect of elimination diets on specific EoE transcripts and their clinical correlates is relatively unknown. The main aim of the study was to evaluate the effect of dietary treatment (four-food elimination diet [FFED]) with or without addition of amino acid-based formula (AAF) on a variety of pro-/anti-inflammatory, epithelial/barrier function and remodeling/fibrosis-related markers of disease activity and clinical correlates (eosinophils, symptoms, and endoscopic signs) in adult EoE patients. METHODS: We conducted an analysis of biopsy samples and data collected during a randomized controlled trial with an elimination diet in adult patients with active EoE (≥15 eosinophils [eos] per high-power field [hpf]). Demographics, symptoms (SDI-score), endoscopic signs (EREFS) and peak eosinophil counts/hpf were recorded at baseline and after 6 weeks of treatment. Transcripts of 10 indicated genes were measured (qPCR) and compared to clinical correlates at baseline and after treatment. KEY RESULTS: Forty patients (pooled FFED + FFED + AAF) (60% male, age 34.5 (interquartile range [IQR] 29-42.8 years) completed the diet. Peak eosinophil counts/hpf, symptoms and endoscopic signs were significantly decreased after 6 weeks dietary treatment. DSG-1 levels were significantly upregulated from baseline to week 6, whereas IL-13, CAPN-14, IL-5, IL-10, CCL-26, POSTN, TSLP, CPA-3, and TGF-ß were significantly downregulated after 6 weeks of diet (all; <0.01). Prior to treatment, upregulation of CAPN-14 and lower levels of DSG-1 were associated with clinical fibrotic phenotypes, whereas upregulation of IL-10 was linked to food impaction phenotypes. CONCLUSION: These findings strongly suggest that elimination diets, besides a clinical and histological response, are associated with a broad transcriptional response at the level of the esophageal epithelium.

Butyrate and propionate restore interleukin 13-compromised esophageal epithelial barrier function.

BACKGROUND: Eosinophilic esophagitis (EoE) is a food allergen driven disease that is accompanied by interleukin (IL) 13 overexpression and esophageal barrier dysfunction allowing transepithelial food allergen permeation. Nutraceuticals, such as short-chain fatty acids (SCFAs) that restore barrier function and increase immune fitness may be a promising tool in the management of EoE. Here, we investigated the effects of the SCFAs acetate, propionate, and butyrate on an IL-13-compromised human esophageal epithelial barrier, including the mechanisms involved. METHODS: An air-liquid interface culture model of differentiated human EPC2-hTERT (EPC2) was used to study whether SCFAs could restore barrier function after IL-13-induced impairment. Esophageal epithelial barrier function was monitored by transepithelial electrical resistance (TEER) and FITC-dextran paracellular flux, and was further examined by qPCR and immunohistochemical analysis. G protein-coupled receptor (GPR) GPR41, GPR43, GPR109a, or histone deacetylase (HDAC) (ant)agonists were used to assess mechanisms of action of SCFAs. RESULTS: IL-13 stimulation decreased TEER and increased FITC flux, which was counteracted by butyrate and propionate, but not acetate treatment. Barrier proteins FLG and DSG1 mRNA expression was upregulated following butyrate and propionate treatment, whereas expression of eosinophil chemoattractant CCL26 and protease CAPN14 was downregulated. Similarly, butyrate and propionate restored FLG and DSG1 protein expression. Similar effects were observed with an HDAC antagonist but not with GPR agonists. CONCLUSION: Nutraceuticals butyrate and propionate restore the barrier function of esophageal epithelial cells after an inflammatory insult and may be of therapeutic benefit in the management of EoE.