Tissue Remodeling in Chronic Eosinophilic Esophageal Inflammation: Parallels in Asthma and Therapeutic Perspectives.
ABSTRACT: Chronic eosinophilic inflammation is associated with tissue remodeling and fibrosis in a number of chronic T-helper 2 (Th2)-mediated diseases including eosinophilic esophagitis (EoE) and asthma. Chronic inflammation results in dysregulated tissue healing, leading to fibrosis and end organ dysfunction, manifesting clinically as irreversible airway obstruction in asthma and as esophageal rigidity, strictures, narrowing, dysmotility, dysphagia, and food impactions in EoE. Current therapies for EoE and asthma center on reducing inflammation-driven tissue remodeling and fibrosis with corticosteroids, coupled with symptomatic control and allergen avoidance. Additional control of Th2 inflammation can be achieved in select asthma patients with biologic therapies such as anti-IL-5 and anti-IL-13 antibodies, which have also been trialed in EoE. Recent molecular analysis suggests an emerging role for structural cell dysfunction, either inherited or acquired, in the pathogenesis and progression of EoE and asthma tissue remodeling. In addition, new data suggest that inflammation-independent end organ rigidity can alter structural cell function. Herein, we review emerging data and concepts for the pathogenesis of tissue remodeling and fibrosis primarily in EoE and relevant pathogenetic parallels in asthma, focusing additionally on emerging disease-specific therapies and the ability of these therapies to reduce tissue remodeling in subsets of patients.
Project description:Eosinophilic esophagitis (EoE) is a chronic Th2 antigen-driven disorder associated with tissue remodeling. Inflammation and remodeling lead to esophageal rigidity, strictures, and dysphagia. TGF?1 drives esophageal remodeling including epithelial barrier dysfunction and subepithelial fibrosis. A functional SNP in the TGF?1 gene that increases its transcription (C-509T) is associated with elevated numbers of esophageal TGF?1-expressing cells. We utilized esophageal biopsies and fibroblasts from TT-genotype EoE children to understand if TGF?1 influenced fibroblast and epithelial cell function in vivo. Genotype TT EoE esophageal fibroblasts had higher baseline TGF?1, collagen1?1, periostin, and MMP2 (p?<?0.05) gene expression and distinct contractile properties compared with CC genotype (n?=?6 subjects per genotype). In vitro TGF?1 exposure caused greater induction of target gene expression in genotype CC fibroblasts (p?<?0.05). Esophageal biopsies from TT-genotype subjects had significantly less epithelial membrane-bound E-cadherin (p?<?0.01) and wider cluster distribution at nanometer resolution. TGF?1 treatment of stratified primary human esophageal epithelial cells and spheroids disrupted transepithelial resistance (p?<?0.001) and E-cadherin localization (p?<?0.0001). A TGF?1-receptor-I inhibitor improved TGF?1-mediated E-cadherin mislocalization. These data suggest that EoE severity can depend on genotypic differences that increase in vivo exposure to TGF?1. TGF?1 inhibition may be a useful therapy in subsets of EoE patients.
Project description:Eosinophilic esophagitis (EoE) is a chronic antigen mediated disease associated with substantial esophageal remodeling and fibrosis. The functional TGF?1 promoter SNP C-509 associates with renal fibrosis and asthma. The effect of TGF?1 genotype and EoE severity or potential gene-environment interactions have not been previously reported in EoE.Genotype at TGF?1 C-509T and remodeling was analyzed in 144 subjects with EoE. The severity of remodeling and inflammation was analyzed in the context of IgE sensitization to food antigens and C-509T genotype.The TGF?1 promoter C-509 genotypes CC, CT, and TT were 35%, 52%, and 13%, respectively. Sixty-six percent of subjects were sensitized to foods by positive skin prick test (SPT) or serum specific IgE. TT genotype subjects had significantly more TGF?1 (CC subjects = 1300 per mm2; TT = 2250 per mm2) (p<0.05) and tryptase (CC subjects = 145 per mm2: TT = 307 per mm2) (p<0.05) positive cells and higher epithelial remodeling scores (2.4 vs 3.7, p<0.001) than CC subjects. The differences in TGF?1 and tryptase positive cells as well as fibrosis were significantly increased when there was concurrent food sensitization. Food sensitization alone did not associate with any parameters of inflammation or remodeling.Our data support a gene-environment interaction between food and genotype at C-509 that modulates disease severity in EoE. Since EoE subjects often continue to consume foods to which they are sensitized, these findings may have clinical relevance for disease management.
Project description:Eosinophilic esophagitis (EoE) is a chronic TH2 inflammatory disease characterized by tissue remodeling that leads to esophageal strictures and food impactions. Effects of therapy on long-term remodeling in patients with pediatric eosinophil-associated diseases have not been previously described.We sought to understand the long-term control of esophageal remodeling in patients with EoE.We assessed endoscopic and histologic remodeling and TGF-?1 expression in esophageal biopsy specimens from children (n = 32) with EoE treated with topical corticosteroids (TCSs) over 10 years (mean, 4.5 years). We used standardized EoE scoring tools to gauge endoscopic and symptom features.Seven hundred thirty-eight biopsy specimens from 246 endoscopic procedures were evaluated over 10 years. Four hundred eighty-six biopsy specimens had adequate lamina propria for evaluation of subepithelial remodeling. The severity of epithelial esophageal eosinophilia correlated with epithelial remodeling (basal zone hyperplasia, desquamation, and dilated intercellular spaces; P < .0001), lamina propria eosinophilia (P < .0001), and fibrosis (P < .0001). Sixteen subjects were initial responders (<15 eosinophils/high-power field) to TCSs. Responders and nonresponders spent 54% and 97% of their total disease duration with active EoE (P < .001) and 23% and 53% (P < .02) with maximal fibrosis scores, respectively. Responders had lower endoscopy scores during their disease duration (P = .013). Having less than 15 eosinophils/high-power field at any time correlated with lower fibrosis and endoscopic severity. TGF-?1(+) cell counts decreased in responders at the first biopsy, but this was not sustained. Symptoms did not correlate with other disease features.Children with EoE have substantial esophageal remodeling, which associates with inflammation and can improve in a sustainable manner with TCSs. Although endoscopic features correspond to histologic features, symptoms did not correlate with inflammation or fibrosis.
Project description:Eosinophilic esophagitis (EoE) is an allergy-mediated disease culminating in severe eosinophilic inflammation and dysfunction of the esophagus. This chronic disorder of the esophagus causes significant morbidity, poor quality of life, and complications involving fibrosis and esophageal remodeling. Overlapping features between EoE and gastroesophageal reflux disease (GERD) pose great challenges to differentiating the two conditions, although the two disorders are not mutually exclusive. Recent findings suggest that the confounding condition proton pump inhibitor - responsive esophageal eosinophilia (PPI-REE) is likely a subset of EoE. Since PPIs have therapeutic properties that can benefit EoE, PPIs should be considered as a therapeutic option for EoE rather than a diagnostic screen to differentiate GERD, PPI-REE, and EoE. Other current treatments include dietary therapy, corticosteroids, and dilation. Immunomodulators and biologic agents might have therapeutic value, and larger trials are needed to assess efficacy and safety. Understanding the pathophysiology of EoE is critical to the development of novel therapeutics.
Project description:Macrophage migration inhibitory factor (MIF) is involved in eosinophil biology and in type 2 inflammation, contributing to allergic and helminthic diseases. We hypothesized that MIF participates in the pathogenesis of eosinophilic esophagitis (EoE), an allergic condition characterized by esophageal eosinophilic inflammation. MIF is highly expressed in esophageal mucosa of patients with EoE, compared with gastro-esophageal reflux disease and control patients, where it co-localizes predominantly with eosinophils. In vitro, recombinant MIF promotes human eosinophil chemotaxis, while MIF antagonist and CXCR4 antagonist, AMD3100, revert this effect. In a model of EoE induced by ovalbumin, Mif-deficient mice have reduced inflammation and collagen deposition compared with wild-type (WT) mice. Importantly, treatment of WT mice with anti-MIF or with AMD3100 during the challenge phase prevents accumulation of eosinophils and tissue remodeling. Conversely, recombinant MIF promoted tissue eosinophil inflammation in allergic mice. Together, these results implicate MIF in the pathogenesis of esophageal inflammation and suggest that targeting MIF might represent a novel therapy for EoE.
Project description:PURPOSE OF REVIEW:Eosinophilic Esophagitis (EoE) is an emerging chronic atopic disease. Recent advances in understanding its genetic and molecular biology pathogenesis may lead to a better management of the disease RECENT FINDINGS:EoE is an atopic disease. Most of the patients affected by EoE have other atopic diseases such as allergic rhinitis, asthma, IgE-mediated food allergies and/or atopic dermatitis. The local inflammation is a T helper type 2 (Th2) flogosis, which most likely is driven by a mixed IgE and n-IgE-mediated reaction to food and/or environmental allergens. Epidemiological studies show that EoE is an atopic disease with a strong genetic component. Genetic studies have shown that EoE is associated with single nucleotide polymorphism on genes, which are released by the epithelium and important in atopic inflammation such as thymic stromal lymphopoietin located (TSLP) close to the Th2 cytokine cluster [interleukin (IL)-4, IL-5, IL-13] on chromosome 5q22, Calpain 14, EMSY, and Eotaxin3. When the EoE diagnosis is made, it is imperative to control the local eosinophilic inflammation not only to give symptomatic relief to the patient, but also to prevent complications such as esophageal stricture and food impaction. SUMMARY:EoE is treated like many other atopic diseases with a combination of topical steroids and/or food antigen avoidance. The new understanding of EoE may lead to more specific and definitive treatments of EoE.
Project description:Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker's asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.
Project description:Asthma is canonically thought of as a disorder of excessive Th2-driven inflammation in the airway, although recent studies have described heterogeneity with respect to asthma pathophysiology. We have previously described distinct phenotypes of asthma based on the presence or absence of a three-gene "Th2 signature" in bronchial epithelium, which differ in terms of eosinophilic inflammation, mucin composition, subepithelial fibrosis, and corticosteroid responsiveness. In the present analysis, we sought to describe Th2 inflammation in human asthmatic airways quantitatively with respect to known mediators of inflammation and intercellular communication. Using whole-genome microarray and quantitative real-time PCR analysis of endobronchial biopsies from 27 mild-to-moderate asthmatics and 13 healthy controls with associated clinical and demographic data, we found that asthmatic Th2 inflammation is expressed over a variable continuum, correlating significantly with local and systemic measures of allergy and eosinophilia. We evaluated a composite metric describing 79 coexpressed genes associated with Th2 inflammation against the biological space comprising cytokines, chemokines, and growth factors, identifying distinctive patterns of inflammatory mediators as well as Wnt, TGF-?, and platelet-derived growth factor family members. This integrated description of the factors regulating inflammation, cell migration, and tissue remodeling in asthmatic airways has important consequences for the pathophysiological and clinical impacts of emerging asthma therapeutics targeting Th2 inflammation.
Project description:Eosinophilic esophagitis (EoE) is a Th2 cytokine-associated disease characterized by eosinophil infiltration, epithelial cell hyperplasia, and tissue remodeling. Recent studies highlighted a major contribution for IL-13 in EoE pathogenesis. Paired Ig-like receptor B is a cell surface immune-inhibitory receptor that is expressed by eosinophils and postulated to regulate eosinophil development and migration. We report that Pirb is upregulated in the esophagus after inducible overexpression of IL-13 (CC10-Il13(Tg) mice) and is overexpressed by esophageal eosinophils. CC10-Il13(Tg)/Pirb(-/-) mice displayed increased esophageal eosinophilia and EoE pathology, including epithelial cell thickening, fibrosis, and angiogenesis, compared with CC10-Il13(Tg)/Pirb(+/+) mice. Transcriptome analysis of primary Pirb(+/+) and Pirb(-/-) esophageal eosinophils revealed increased expression of transcripts associated with promoting tissue remodeling in Pirb(-/-) eosinophils, including profibrotic genes, genes promoting epithelial-to-mesenchymal transition, and genes associated with epithelial growth. These data identify paired Ig-like receptor B as a molecular checkpoint in IL-13-induced eosinophil accumulation and activation, which may serve as a novel target for future therapy in EoE.
Project description:Eosinophilic disorders of the gastrointestinal tract are an emerging subset of immune pathologies within the spectrum of allergic inflammation. Eosinophilic Esophagitis (EoE), once considered a rare disease, is increasing in incidence, with a rate of over 1 in 10,000 in the US, for unknown reasons. The clinical management of EoE is challenging, thus there is an urgent need for understanding the etiology and pathophysiology of this eosinophilic disease to develop better therapeutic approaches. In this open label, single arm, unblinded study, we evaluated the effects of an anti-IgE treatment, omalizumab, on local inflammation in the esophagus and clinical correlates in patients with EoE. Omalizumab was administered for 12 weeks to 15 subjects with long standing EoE. There were no serious side effects from the treatment. Esophageal tissue inflammation was assessed both before and after therapy. After 3 months on omalizumab, although tissue Immunoglobulin E (IgE) levels were significantly reduced in all but two of the subjects, we found that full remission of EoE, which is defined as histologic and clinical improvement only in 33% of the patients. The decrease in tryptase-positive cells and eosinophils correlated significantly with the clinical outcome as measured by improvement in endoscopy and symptom scores, respectively. Omalizumab-induced remission of EoE was limited to subjects with low peripheral blood absolute eosinophil counts. These findings demonstrate that in a subset of EoE patients, IgE plays a role in the pathophysiology of the disease and that anti-IgE therapy with omalizumab may result in disease remission. Since this study is open label there is the potential for bias, hence the need for a larger double blind placebo controlled study. The data presented in this pilot study provides a foundation for proper patient selection to maximize clinical efficacy.