Esophageal epithelial cells acquire functional characteristics of activated myofibroblasts after undergoing an epithelial to mesenchymal transition

Effect of benralizumab on histopathology and inflammatory signatures in a clinical cohort of eosinophilic esophagitis

A preliminary report from the recent phase 3 trial of benralizumab, a monoclonal antibody that binds to interleukin-5 receptor alpha (IL5Rα), in patients with EoE revealed that medication use led to tissue eosinophil eradication but did not meet the clinical endpoint of symptom resolution. Here, we characterized the clinical, endoscopic, histologic, and transcriptional changes in patients with active EoE following benralizumab treatment. We retrospectively examined patients with EoE treated with benralizumab at the University of Utah (n = 11) and reviewed reported clinical symptoms, circulating and tissue eosinophilia, and endoscopic and histologic scores. Gene expression profiles from available esophageal tissue from benralizumab-treated patients were compared to those from patients with remission EoE (n = 5), active EoE (n = 10), and controls (n = 22). Benralizumab treatment resulted in partial symptom improvement and significant reduction in tissue eosinophilia, and endoscopic and histologic disease scoring (P < 0.01). Histologic score reductions were driven by eosinophil feature scores, while scores for epithelial features (basal cell hyperplasia and dilated intercellular spaces) were similar to those in active EoE. The gene signatures in benralizumab-treated patients mimicked those of active EoE (e.g. upregulation of POSTN, CDH26, CCL26, and downregulation of DSG1). RNA profiles and pathways support histologic findings of impaired epithelial function that persists despite benralizumab treatment. In conclusion, despite eosinophil eradication, patients treated with benralizumab had persistent epithelial injury at the histologic and transcriptional level. In this cohort, benralizumab therapy failed to eradicate inflammation and epithelial dysfunction showing that interleukin-5 receptor alpha blockade monotherapy is insufficient to control EoE.

Esophageal remodeling in eosinophilic esophagitis

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a Th2 immune/antigen-mediated disorder characterized by esophageal dysfunction and eosinophilic inflammation. Worsening dysphagia and food impactions are significant complications associated with esophageal remodeling and fibrostenotic disease. This review highlights the most recent research findings pertaining to mechanisms of sub-epithelial fibrosis in EoE, current diagnostic tools, and therapeutic approaches.

RECENT FINDINGS

Recent studies leveraging publicly available single cell sequencing databases and comparative proteomics have furthered our understanding of the mechanisms mediating fibrosis. Fibroblast crosstalk with the extracellular matrix and with epithelial, endothelial, and T cells have been implicated, with the likely existence of multiple fibroblast sub-types. Accurate diagnosis of remodeling with biopsies remains a challenge due to inadequate depth of sampling. Web-based tools incorporating epithelial findings show promise in predicting subepithelial fibrosis. Impedance planimetry with esophageal distensibility measurements are increasingly utilized tools to assess fibrostenotic severity. Immunostaining and luminal captured proteins associated with remodeling show promise as potential molecular markers of fibrosis. Anti-inflammatory therapy may improve esophageal fibrosis and distensibility, although specific fibrosis-targeted therapy is lacking.

SUMMARY

Recent studies highlight novel mechanisms of fibrosis in EoE. Improved understanding of these mechanisms may lead to novel diagnostic strategies and therapies, and thereby inform treatment decisions.

Differential Contributions of Fibroblast Subpopulations to Intercellular Communication in Eosinophilic Esophagitis

Fibroblast heterogeneity remains undefined in eosinophilic esophagitis (EoE), an allergic inflammatory disorder complicated by fibrosis. We utilized publicly available single-cell RNA sequencing data (GSE201153) of EoE esophageal biopsies to identify fibroblast sub-populations, related transcriptomes, disease status-specific pathways and cell-cell interactions. IL13-treated fibroblast cultures were used to model active disease. At least 2 fibroblast populations were identified, F_A and F_B. Several genes including ACTA2 were more enriched in F_A. F_B percentage was greater than F_A and epithelial-mesenchymal transition upregulated in F_B vs. F_A in active and remission EoE. Epithelial-mesenchymal transition was also upregulated in F_B in active vs. remission EoE and TNF-α signaling via NFKB was downregulated in F_A. IL-13 treatment upregulated ECM-related genes more profoundly in ACTA2- fibroblasts than ACTA2+ myofibroblasts. After proliferating epithelial cells, F_B and F_A contributed most to cell-cell communication networks. ECM-Receptor interaction strength was stronger than secreted or cell-cell contact signaling in active vs. remission EoE and significant ligand-receptor pairs were driven mostly by F_B. This unbiased analysis identifies at least 2 fibroblast sub-populations in EoE in vivo, distinguished in part by ACTA2. Fibroblasts play a critical role in cell-cell interactions in EoE, most profoundly via ECM-receptor signaling via the F_B sub-group.

Development and dysfunction of structural cells in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a disorder characterized by dysfunction and chronic local inflammation of the esophagus. The incidence and prevalence of EoE are increasing worldwide. The mechanisms responsible are poorly understood, and effective treatment options are limited. From the lumen outward, the esophagus comprises stratified squamous epithelium, lamina propria, and muscle. The tissue-specific nature of EoE strongly suggests that structural cells in the esophagus are involved in the EoE diathesis. Epithelial basal cell hyperplasia and dilated intercellular spaces are cardinal features of EoE. Some patients with EoE develop lamina propria fibrosis, strictures, or esophageal muscle dysmotility. Clinical symptoms of EoE are only weakly correlated with peak eosinophil count, implying that other cell types contribute to EoE pathogenesis. Epithelial, endothelial, muscle, and fibroblast cells can each initiate inflammation and repair, regulate tissue resident immune cells, recruit peripheral leukocytes, and tailor adaptive immune cell responses. A better understanding of how structural cells maintain tissue homeostasis, respond to cell-intrinsic and cell-extrinsic stressors, and exacerbate and/or resolve inflammatory responses in the esophagus is needed. This knowledge will facilitate the development of more efficacious treatment strategies for EoE that can restore homeostasis of both hematopoietic and structural elements in the esophagus.

Histopathology of Eosinophilic Esophagitis

Microscopic examination of esophageal biopsies is essential to diagnose eosinophilic esophagitis (EoE). Eosinophil inflammation is the basis for the diagnosis, but additional abnormalities may contribute to persistent symptoms and epithelial barrier dysfunction. Both peak eosinophil count and assessments of additional features should be included in pre-therapy and post-therapy pathology reports. Pathologic abnormalities identified in esophageal biopsies of EoE are reversible in contrast to esophageal strictures.

Epithelial-Fibroblast Crosstalk in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an emerging form of food allergy that exerts a significant clinical and financial burden worldwide. EoE is clinically characterized by eosinophil-rich inflammatory infiltrates in esophageal mucosa and esophageal dysfunction. Remodeling events in esophageal epithelium and lamina propria also frequently occur in patients with EoE. Because subepithelial fibrosis is associated with esophageal stricture, the most severe consequence of EoE, there exists an urgent need for a deeper understanding of the molecular mechanisms mediating fibrosis in EoE. Here, we review emerging evidence from experimental model systems that implicates crosstalk between esophageal epithelial cells and underlying stromal cells in EoE fibrosis. We further discuss implications for epithelial-stromal interaction with regard to EoE patient care and propose future directions that may be pursued to further the understanding of epithelial-stromal crosstalk in EoE pathobiology.

Fibrous Remodeling in Eosinophilic Esophagitis: Clinical Facts and Pathophysiological Uncertainties

Eosinophilic esophagitis (EoE) is a chronic, progressive, type 2 inflammatory disease with increasing global prevalence. An eosinophil-predominant inflammation that permeates the epithelium and deeper esophageal layers characterizes the disease. Several cytokines, mainly derived from inflammatory T-helper 2 (Th2) cells and epithelial cells, are involved in perpetuating inflammatory responses by increasing surface permeability and promoting tissue remodeling characterized by epithelial-mesenchymal transition (EMT) and collagen deposition. This leads to esophageal strictures and narrow caliber esophagi, which are proportional a patient's age and untreated disease length. Pathophysiological mechanisms leading to EoE have been described in recent years, and transforming growth factor beta (TGF)-beta have been involved in fibrotic phenomena in EoE. However, evidence on the dependence of these phenomena on TGF-beta is scarce and contradictory. This review provides state-of-the art knowledge on intimate mechanisms of esophageal fibrosis in EoE and its clinical consequences.

Histological Phenotyping in Eosinophilic Esophagitis: Localized Proximal Disease Is Infrequent but Associated with Less Severe Disease and Better Disease Outcome

INTRODUCTION

It is still unknown whether eosinophilic esophagitis (EoE) patients with localized disease are different from those with extended disease.

METHODS

We evaluated prospectively included patients in the Swiss EoE cohort. Data on all patients with active disease at baseline, no concomitant gastroesophageal reflux disease, no strictures at baseline, and at least one follow-up visit were analyzed. We compared patients with histologically localized proximal versus distal versus extended (=proximal and distal) disease with regard to patient, disease characteristics, disease presentation, and development of complications.

RESULTS

We included 124 patients with a median of 2.5 years of follow-up (73.4% males, median age 35.0 years). Ten patients had proximal (8.1%), 46 patients had distal (37.1%), and 68 patients had extended disease (54.8%). Patients with proximal disease were significantly more often females (80%) compared with patients with distal (26.1%, p = 0.002) or extended disease (19.1%, p < 0.001) and reported less severe symptoms (VAS 0 vs. VAS 1, p = 0.001). Endoscopic and histological disease was less pronounced in the proximal esophagus of proximal EoE compared to extended disease (EREFS 1.0 vs. 3.0, p = 0.001; 27.0 eos/hpf vs. 52.5 eos/hpf, p = 0.008). Patients with proximal disease were less likely to undergo dilation compared to patients with distal disease in the follow-up (3.3% vs. 23.3%, p = 0.010). In a multivariate Cox regression model, proximal eosinophilia was less likely to be associated with treatment failure compared to distal eosinophilia.

CONCLUSION

Although isolated proximal EoE is infrequent, it is associated with less severe disease and better disease outcome. Proximal disease appears to present a unique EoE phenotype.

Lysyl oxidase regulates epithelial differentiation and barrier integrity in eosinophilic esophagitis

Background & Aims

Epithelial disruption in eosinophilic esophagitis (EoE) encompasses both impaired differentiation and diminished barrier integrity. We have shown that lysyl oxidase (LOX), a collagen cross-linking enzyme, is upregulated in the esophageal epithelium in EoE. However, the functional roles of LOX in the esophageal epithelium remains unknown.

Methods

We investigated roles for LOX in the human esophageal epithelium using 3-dimensional organoid and air-liquid interface cultures stimulated with interleukin (IL)-13 to recapitulate the EoE inflammatory milieu, followed by single-cell RNA sequencing, quantitative reverse transcription-polymerase chain reaction, western blot, histology, and functional analyses of barrier integrity.

Results

Single-cell RNA sequencing analysis on patient-derived organoids revealed that LOX was induced by IL-13 in differentiated cells. LOX-overexpressing organoids demonstrated suppressed basal and upregulated differentiation markers. Additionally, LOX overexpression enhanced junctional protein genes and transepithelial electrical resistance. LOX overexpression restored the impaired differentiation and barrier function, including in the setting of IL-13 stimulation. Transcriptome analyses on LOX-overexpressing organoids identified enriched bone morphogenetic protein (BMP) signaling pathway compared to wild type organoids. Particularly, LOX overexpression increased BMP2 and decreased BMP antagonist follistatin. Finally, we found that BMP2 treatment restored the balance of basal and differentiated cells.

Conclusions

Our data support a model whereby LOX exhibits non-canonical roles as a signaling molecule important for epithelial homeostasis in the setting of inflammation via activation of BMP pathway in esophagus. The LOX/BMP axis may be integral in esophageal epithelial differentiation and a promising target for future therapies.

Mechanisms of esophageal stricture after extensive endoscopic resection: a transcriptomic analysis

Background and study aims  Esophageal stricture is the most frequent adverse event after endoscopic resection for early esophageal neoplasia. Currently available treatments for the prevention of esophageal stricture are poorly effective and associated with major adverse events. Our aim was to identify transcripts specifically overexpressed or repressed in patients who have developed a post-endoscopic esophageal stricture, as potential targets for stricture prevention. Patients and methods  We conducted a prospective single-center study in a tertiary endoscopy center. Patients scheduled for an endoscopic resection and considered at risk of esophageal stricture were offered inclusion in the study. The healthy mucosa and resection bed were biopsied on Days 0, 14, and 90. A transcriptomic analysis by microarray was performed, and the differences in transcriptomic profile compared between patients with and without esophageal strictures. Results  Eight patients, four with esophageal stricture and four without, were analyzed. The mean ± SD circumferential extension of the mucosal defect was 85 ± 11 %. The transcriptomic analysis in the resection bed at day 14 found an activation of the interleukin (IL)-1 group (Z score = 2.159, P  = 0.0137), while interferon-gamma (INFγ) and NUPR1 were inhibited (Z score = -2.375, P  = 0.0022 and Z score = -2.333, P  = 0.00131) in the stricture group. None of the activated or inhibited transcripts were still significantly so in any of the groups on Day 90. Conclusions  Our data suggest that IL-1 inhibition or INFγ supplementation could constitute promising targets for post-endoscopic esophageal stricture prevention.

A role for age-associated alterations in esophageal epithelium in eosinophilic esophagitis-associated fibrosis

Subepithelial fibrosis occurs in a subset of eosinophilic esophagitis (EoE) patients and is associated with esophageal stricture. While mechanisms driving EoE fibrosis remain incompletely understood, findings from experimental systems support roles for epithelial-fibroblast crosstalk in this type of tissue remodeling. The current paradigm presents EoE as a progressive fibrostenotic disease in which aged patients develop fibrosis as a function of disease chronicity. In the current study we provide evidence that altered epithelial biology in the aging esophagus may also contribute to EoE-associated fibrosis. We find that induction of EoE inflammation in young and aged mice using the MC903/Ovalbumin protocol for the same time period results in increased lamina propria thickness uniquely in aged animals. Additionally, epithelial cells from aged mice less efficiently limit fibroblast contractility in collagen plug contraction assays compared to those from their young counterparts. Finally, to identify potential mechanisms through which aged esophageal epithelial cells may stimulate fibrotic remodeling, we perform cytokine array experiments in young and aged mice. These studies are significant as identification of age-associated factors that contribute to fibrotic remodeling may aid in the design of strategies toward early detection, prevention, and therapy of fibrostenotic EoE.

Esophageal remodeling in eosinophilic esophagitis: Relationships to luminal captured biomarkers of inflammation and periostin

BACKGROUND

Esophageal remodeling is a factor in disease progression and symptom severity for patients with eosinophilic esophagitis (EoE). Remodeling can begin early in children, resulting in stricture and food impaction. Detection of esophageal remodeling often depends on endoscopy and is appreciated only in its later stages.

OBJECTIVE

We sought to determine whether luminal eosinophil-associated and remodeling proteins captured by the esophageal string test (EST) correlate with measures of esophageal remodeling and biomarkers of the epithelial-mesenchymal transition (EMT).

METHODS

Patients with EoE (7-18 years old) were enrolled from 2 pediatric hospitals. Participants performed the EST and underwent endoscopy. Histology, distensibility measured by endoluminal functional lumen imaging probe, and symptoms were assessed. Protein quantitation by ELISA was performed on mucosal biopsy and EST samples. Tissue sections were evaluated for EMT. Outcome measures were summarized, and Spearman ρ was used to assess bivariate correlations.

RESULTS

Forty patients (68% male) were enrolled (mean age, 12.5 years). Twenty-four (60%) had active disease (≥15 eosinophils per high-power field). EST-captured eotaxin-3, major basic protein 1, EDN, eosinophil peroxidase, and Charcot-Leyden crystal protein/galectin-10 showed significant correlations with peak eosinophils per high-power field (ρ 0.53-0.68, P < .001). Luminal proteins positively correlated with endoscopic features and markers of EMT, and negatively with esophageal distensibility. Periostin was captured by the EST and correlated with eosinophil density, basal zone hyperplasia, endoscopic appearance, and markers of EMT.

CONCLUSION

Luminal markers of esophageal remodeling in addition to biomarkers of eosinophilic inflammation correlate with epithelial and functional remodeling in EoE.

Eosinophilic esophagitis auxiliary diagnosis based on a peptide ligand to eosinophil cationic protein in esophageal mucus of pediatric patients

Eosinophilic esophagitis (EoE) is a chronic inflammatory condition of the esophagus characterized by increased number of eosinophils. Currently, EoE diagnosis is based on endoscopic procedures for histopathological examination, eosinophils' counting and, often, in clinical practice, the challenge is the differentiation between EoE and gastroesophageal reflux disease (GERD). Our aim was to develop novel peptide ligand to Eosinophil cationic protein (ECP) present in EoE biopsies of patients with potential to be used for detection. We performed a comparative proteomic analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) of esophageal biopsies from pediatric patients with eosinophilic esophagitis, gastroesophageal reflux disease and control individuals. Then, phage display technology was used to select peptides against specific up-regulated protein from EoE patients. Twelve phage clones were selected after three biopanning rounds, and the best phage clone reactivity was evaluated by phage-ELISA assay using esophageal mucus samples from 94 pediatric patients. Mass spectrometry showed that eosinophil cationic protein (ECP) was one of the most up-regulated proteins in EoE patients, which is an eosinophil granule protein usually deposited on tissues to mediate remodeling, but in excess may cause fibrosis and hypertrophy, especially in allergic responses. A highly reactive ECP-ligand peptide (E5) was able to distinguish reactive mucus of EoE patients from GERD and the control individuals by Phage-ELISA, achieving a sensitivity of 84.62%, and a specificity of 82.72%. This is the first study that successfully demonstrated an antibody-like peptide targeting ECP at the esophagus mucus as a useful auxilliary tool for EoE diagnosis with a significant association with atopic disorders and dysphagia.ClinicalTrials.gov no.: NCT03069573.

Epithelial-mesenchymal transition, regulated by β-catenin and Twist, leads to esophageal wall remodeling in pediatric eosinophilic esophagitis

Eosinophilic Esophagitis (EoE) is an antigen-triggered inflammatory condition of the esophageal lining characterized by eosinophilic infiltration. EoE is associated with significant remodeling, and although this remodeling is reversed by current treatment regimens, symptoms of EoE and associated remodeling reappear upon cessation of therapies. We hypothesized that structural remodeling of cell-cell adhesion is a key factor in the pathogenesis of EoE and that epithelial to mesenchymal transition (EMT) was a viable molecular process to lead to this remodeling. Endoscopically obtained biopsy samples from 18 EoE and 18 control pediatric patients were evaluated by transmission electron microscopy to measure intercellular spaces (IS) between cells. Biopsy samples from all groups were analyzed for cellular levels of cell-cell adhesion proteins: E-cadherin, zonula occludens associated protein-1 (ZO-1), and N-cadherin. We also analyzed for cellular levels and localization two of transcription factors, Twist1 and β-catenin, that are associated with promoting EMT. The IS was significantly increased in the EoE group compared to the control. We observed a significant decrease in E-cadherin and ZO-1 levels and a concomitant increase in N-cadherin levels in EoE samples compared to control. Further, while there was no significant change in cellular levels of β-catenin, we observed an altered localization of the protein from the cell membrane in control tissue to a nuclear/perinuclear localization in EoE. We observed higher levels of the transcription factor Twist1 in the EoE group compared to normal which was localized mainly at the nucleus. Our results suggest that the integrity of normally sealed esophageal epithelia is compromised in the EoE patients compared to control subjects, and this is due to alterations in the expression of cell adhesion molecules at the esophageal epithelium. Our data also suggest that EMT, potentially regulated by transcription factors β-catenin and Twist1, may be responsible for the molecular alteration which leads to the remodeling of esophageal epithelia in EoE.

CD73+ Epithelial Progenitor Cells That Contribute to Homeostasis and Renewal Are Depleted in Eosinophilic Esophagitis

BACKGROUND & AIMS

Although basal cell hyperplasia is a histologic hallmark of eosinophilic esophagitis (EoE), little is known about the capabilities of epithelial renewal and differentiation in the EoE inflammatory milieu. In murine esophageal epithelium, there are self-renewing and slowly proliferating basal stem-like cells characterized by concurrent expression of CD73 (5'-nucleotidase ecto) and CD104 (integrin β4). Here, we investigated CD73⁺CD104⁺ cells within the basal population of human esophageal epithelium and clarified the biological significance of these cells in the EoE epithelium.

METHODS

We performed flow cytometry on esophageal biopsy samples from EoE and non-EoE patients to determine the quantity of CD73⁺CD104⁺ cells in the epithelium. Simulating the EoE milieu we stimulated primary patient-derived and immortalized cell line-derived esophageal organoids with interleukin (IL)4 and IL13 and analyzed by flow cytometry, immunohistochemistry, and quantitative reverse-transcription polymerase chain reaction. We performed single-cell RNA sequencing on primary organoids in the setting of IL13 stimulation and evaluated the CD73⁺CD104⁺ population. We performed fluorescent-activated cell sorting to purify CD73⁺CD104⁺ and CD73^- CD104⁺ populations and seeded these groups in organoid culture to evaluate the organoid formation rate and organoid size. We used RNA interference to knock down CD73 in esophageal organoids to evaluate organoid formation rates and size. We evaluated the effects of signal transducer and activator of transcription 6 (STAT6) signaling inhibition by RNA interference, a STAT6 inhibitor, AS1517499, as well as the proton pump inhibitor omeprazole.

RESULTS

EoE patients showed decreased epithelial CD73⁺CD104⁺ cell content. IL4 and IL13 stimulation depleted this population in 3-dimensional organoids with a recapitulation of basal cell hyperplasia as corroborated by single-cell RNA sequencing of the organoids, which suggests depletion of CD73⁺CD104⁺ cells. The CD73⁺CD104⁺ population had enhanced organoid formation compared with the CD73^-CD104⁺ population. Similarly, knock-down of CD73 resulted in decreased organoid formation rate. Genetic and pharmacologic inhibition of STAT6 prevented T helper 2 cytokine-induced depletion of CD73⁺CD104⁺ cells. Lastly, omeprazole treatment prevented the effects of IL4 and IL13 on the CD73⁺CD104⁺ population.

CONCLUSIONS

This study addressed the role of CD73⁺CD104⁺ cells in epithelial renewal and homeostasis in the context of EoE. The depletion of the CD73⁺CD104⁺ self-renewal population by helper T cell 2 cytokines in EoE milieu may be perpetuating epithelial injury. Future therapies targeting epithelial restitution in EoE could decrease the need for immune modulation and steroid therapy.

Biologics in eosinophilic esophagitis

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the oesophagus whose incidence is on the rise. Despite maximal use of guideline-based therapies including food elimination diets and steroids, many patients remain symptomatic. This review serves to summarize safety and efficacy of monoclonal antibodies in treatment of EoE.

RECENT FINDINGS

There has been an increasing number of biologics under consideration for EoE and several that have undergone clinical trials. mAbs that target specific effectors involved in the disease may offer additional clinical and histologic benefit. In addition, they offer a more benign adverse effect profile than traditional therapies.

SUMMARY

Biologics for treatment of EoE may result in symptom and histologic improvement and has the potential to treat disease with minimal side effects.

Persistent Basal Cell Hyperplasia Is Associated With Clinical and Endoscopic Findings in Patients With Histologically Inactive Eosinophilic Esophagitis

BACKGROUND & AIMS

Although eosinophil count is the standard used to monitor disease activity in patients with eosinophilic esophagitis (EoE), there are often disparities between patient-reported symptoms and eosinophil counts. We examined the prevalence of epithelial alterations, namely basal cell hyperplasia (BCH) and spongiosis, among patients with inactive EoE (eosinophil counts below 15 following therapy) and aimed to determine whether maintenance of these changes in epithelial morphology are associated with persistent clinical findings.

METHODS

Esophageal biopsies of 243 patients (mean age, 16.9 years) undergoing routine endoscopy at the University of Pennsylvania were evaluated for epithelial BCH and spongiosis. Univariable analysis was used to calculate the association between epithelial changes and symptoms as well as endoscopic findings and peak eosinophil count. We validated our findings using data from a cohort of patients at the University of North Carolina.

RESULTS

The discovery and validation cohorts each included patients with inactive EoE, based on histologic factors, but ongoing BCH and spongiosis. Ongoing BCH, but not spongiosis, in patients with inactive EoE was associated with symptoms (odds ratio, 2.14; 95% CI, 1.03-4.42; P = .041) and endoscopic findings (odds ratio, 7.10; 95% CI, 3.12-16.18; P < .001).

CONCLUSIONS

In patients with EoE, the presence of BCH might indicate ongoing disease activity, independent of eosinophil count. This might account for the persistent symptoms in patients who are considered to be in remission based on histologic factors.

An anti-IL-13 antibody reverses epithelial-mesenchymal transition biomarkers in eosinophilic esophagitis: Phase 2 trial results

BACKGROUND

Fibrostenosis, the most serious eosinophilic esophagitis (EoE) complication, is mediated by epithelial-mesenchymal transition (EMT). Transitioned cells contribute to pathogenesis by overproducing extracellular matrix.

OBJECTIVE

Our aim was to determine whether RPC4046 (anti‒IL-13 mAb) modulates EMT biomarkers in biopsy samples from adults with active EoE in a substudy of a double-blind, placebo-controlled phase 2 trial.

METHODS

Baseline and week 16 esophageal biopsy samples were taken from 69 patients who were randomized to weekly treatment with subcutaneous RPC4046, 180 mg (n = 19), 360 mg (n = 26), or placebo (n = 24). Duplex immunofluorescence slides stained for E-cadherin and vimentin were digitally analyzed by mapping each epithelial cell and recording fluorescence intensities. End points included change from baseline to week 16 in percentage of vimentin-positive epithelial cells (primary), total E-cadherin expression, and vimentin-to-E-cadherin ratio per cell (an average of 47,000 cells per biopsy sample analyzed).

RESULTS

The mean percentage of vimentin-positive cells decreased by 0.94%, 2.75%, and 4.24% in the placebo, low-dose, and high-dose groups, respectively (P =.032 for the high-dose vs placebo group). Mean E-cadherin expression per cell increased 5.6-fold in both dose groups versus in the placebo group (high-dose group P = .047). The increases in E-cadherin expression per cell from baseline to week 16 were correlated with improvements in histology, eosinophil counts, endoscopic findings, and symptoms.

CONCLUSION

RPC4046 significantly reduced EMT markers in adults with active EoE, with greater effects at 360 mg. Together with results for eosinophil density and clinical end points from the main trial, these data support the hypothesis that pharmacologic IL-13 inhibition ameliorates both inflammatory and remodeling pathways and could potentially reduce the risk of fibrostenotic complications.

One-Hour Esophageal String Test: A Nonendoscopic Minimally Invasive Test That Accurately Detects Disease Activity in Eosinophilic Esophagitis

OBJECTIVES

Eosinophilic esophagitis (EoE), a chronic food allergic disease, lacks sensitive and specific peripheral biomarkers. We hypothesized that levels of EoE-related biomarkers captured using a 1-hour minimally invasive Esophageal String Test (EST) would correlate with mucosal eosinophil counts and tissue concentrations of these same biomarkers. We aimed to determine whether a 1-hour EST accurately distinguishes active from inactive EoE or a normal esophagus.

METHODS

In a prospective, multisite study, children and adults (ages 7-55 years) undergoing a clinically indicated esophagogastroduodenoscopy performed an EST with an esophageal dwell time of 1 hour. Subjects were divided into 3 groups: active EoE, inactive EoE, and normal esophageal mucosa. Eosinophil-associated protein levels were compared between EST effluents and esophageal biopsy extracts. Statistical modeling was performed to select biomarkers that best correlated with and predicted eosinophilic inflammation.

RESULTS

One hundred thirty-four subjects (74 children, 60 adults) with active EoE (n = 62), inactive EoE (n = 37), and patient controls with a normal esophagus (n = 35) completed the study. EST-captured eosinophil-associated biomarkers correlated significantly with peak eosinophils/high-power field, endoscopic visual scoring, and the same proteins extracted from mucosal biopsies. Statistical modeling, using combined eotaxin-3 and major basic protein-1 concentrations, led to the development of EoE scores that distinguished subjects with active EoE from inactive EoE or normal esophagi. Eighty-seven percent of children, 95% of parents, and 92% of adults preferred the EST over endoscopy if it provided similar information.

DISCUSSION

The 1-hour EST accurately distinguishes active from inactive EoE in children and adults and may facilitate monitoring of disease activity in a safe and minimally invasive fashion.

Eosinophilic esophagitis: early diagnosis is the key

Eosinophilic esophagitis (EoE) is a disorder which affects all ages, from infancy through adulthood. It typically affects atopic individuals (Table 1) and is a chronic allergic disorder, with foods ubiquitous in the diet being the most described trigger of this isolated eosinophilic inflammation of the esophagus in both adults and children. This inflammatory process leads to esophageal symptoms such as dysphagia and feeding intolerance. In this review, we provide a brief overview of the current state of EoE therapy and symptomatology and then try to make the case for early diagnosis and treatment to prevent some of the long-term consequences of esophageal inflammation.

Eosinophilic esophagitis in children: doubts and future perspectives

Background

Eosinophilic esophagitis (EoE) is a chronic immune-mediated inflammatory disorder and represents the leading cause of food impaction. The pathogenesis of EoE is the result of an interplay between genetic, environmental and host immune system factors. New therapeutic approaches for EoE have been proposed. In this manuscript we review the current evidence regarding EoE management in pediatric age, with a particular focus on new findings related to the efficacy and safety of monoclonal antibodies.

Main body

Conventional therapies have failed in treating some patients with EoE, which then requires aggressive procedures such as esophageal dilatation. The most effective available medical therapy for EoE is swallowed topic corticosteroids (fluticasone propionate and budesonide), which have two main drawbacks: they are related to well-known adverse effects (especially in the paediatric population), and there are not enough long-term data to confirm that they are able to reverse the remodelling process of the esophageal mucosa, which is the major cause of EoE symptoms (including dysphagia, abdominal pain, nausea, obstruction, perforation and vomiting). The monoclonal antibodies appear to be an interesting therapeutic approach. However, the studies conducted until now have shown substantial histological improvement not coupled with significant clinical improvements and no significant relationship between a decreasing number of eosinophils and clinical symptoms, highlighting the importance in the pathogenesis of EoE of cells such as T-helper cells, mast cells, B cells, epithelial cells and natural killer cells.

Conclusions

Monoclonal antibodies targeting a signal involved in the pathogenesis of EoE may not break the complex self-propagating inflammatory activation responsible for perpetuation of the inflammatory response and the development of symptoms and complications. We speculate that combined biological therapies targeting more than one molecule or cell may provide better results, with conventional therapies potentially enhancing the effects of antibodies. However, further studies should aim to find the best therapeutic approach to target the cells involved in the remodelling process and to reverse the histological changes in this complex clinical condition.

Epithelial origin of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory disease of the esophagus characterized predominantly by eosinophilic inflammation, leading to esophageal dysfunction. Converging data have placed the esophageal epithelium at the center of disease pathogenesis. In particular, the main EoE disease susceptibility loci at 2p23 and 5p22 encode for gene products that are produced by the esophageal epithelium: the intracellular protease calpain 14 and thymic stromal lymphopoietin, respectively. Furthermore, genetic and functional data establish a primary role for impaired epithelial barrier function in disease susceptibility and pathoetiology. Additionally, the EoE transcriptome, a set of genes dysregulated in the esophagi of patients with EoE, is enriched in genes that encode for proteins involved in esophageal epithelial cell differentiation. This transcriptome has a high proportion of esophagus-specific epithelial genes that are notable for the unexpected enrichment in genes encoding for proteases and protease inhibitors, as well as in IL-1 family genes, demonstrating a previously unappreciated role for innate immunity responses in the esophagus under homeostatic conditions. Among these pathways, basal production of the serine protease inhibitor, Kazal-type 7 (SPINK7) has been demonstrated to be part of the normal differentiation program of esophageal epithelium. Profound lost expression of SPINK7 occurs in patients with EoE and is sufficient for unleashing increased proteolytic activity (including urokinase plasminogen activator), impaired barrier function, and production of large quantities of proinflammatory and proallergic cytokines, including thymic stromal lymphopoietin. Collectively, we put forth a model in which the esophagus is normally equipped as an anti-inflammatory sensing organ and that defects in this pathway, mediated by epithelial protease/protease inhibitor imbalances, unleash inflammatory responses resulting in disorders, such as EoE.

Fibrostenotic eosinophilic esophagitis might reflect epithelial lysyl oxidase induction by fibroblast-derived TNF-α

BACKGROUND

Fibrosis and stricture are major comorbidities in patients with eosinophilic esophagitis (EoE). Lysyl oxidase (LOX), a collagen cross-linking enzyme, has not been investigated in the context of EoE.

OBJECTIVE

We investigated regulation of epithelial LOX expression as a novel biomarker and functional effector of fibrostenotic disease conditions associated with EoE.

METHODS

LOX expression was analyzed by using RNA-sequencing, PCR assays, and immunostaining in patients with EoE; cytokine-stimulated esophageal 3-dimensional organoids; and fibroblast-epithelial cell coculture, the latter coupled with fluorescence-activated cell sorting.

RESULTS

Gene ontology and pathway analyses linked TNF-α and LOX expression in patients with EoE, which was validated in independent sets of patients with fibrostenotic conditions. TNF-α-mediated epithelial LOX upregulation was recapitulated in 3-dimensional organoids and coculture experiments. We find that fibroblast-derived TNF-α stimulates epithelial LOX expression through activation of nuclear factor κB and TGF-β-mediated signaling. In patients receiver operating characteristic analyses suggested that LOX upregulation indicates disease complications and fibrostenotic conditions in patients with EoE.

CONCLUSIONS

There is a novel positive feedback mechanism in epithelial LOX induction through fibroblast-derived TNF-α secretion. Esophageal epithelial LOX might have a role in the development of fibrosis with substantial translational implications.

Epithelial-stromal crosstalk and fibrosis in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a food allergen-induced inflammatory disorder. EoE is increasingly recognized as a cause of swallowing dysfunction, food impaction and esophageal stricture. Inflammation of the esophageal mucosa involves immune cell infiltrate, reactive epithelial changes and fibroblast activation, culminating in robust tissue remodeling toward esophageal fibrosis characterized by excess collagen deposition in the subepithelial lamina propria. Fibrosis contributes to a unique mechanical property of the EoE-affected esophagus that is substantially stiffer than the normal esophagus. There is a great need to better understand the processes behind esophageal fibrosis in order to foster improved diagnostic tools and novel therapeutics for EoE-related esophageal fibrosis. In this review, we discuss the role of esophageal inflammatory microenvironment that promotes esophageal fibrosis, with specific emphasis upon cytokines-mediated functional epithelial-stromal interplays, recruitment and activation of a variety of effector cells, and tissue stiffness. We then explore the current state of clinical methodologies to detect and treat the EoE-related esophageal stricture.

Eosinophilic esophagitis: pathophysiology and its clinical implications

Classically, eosinophilic esophagitis is an antigen-mediated chronic disease distinct from gastroesophageal reflux disease. Eosinophilic esophagitis is an emerging clinical problem that is growing in recognition. It is characterized clinically by feeding dysfunction, dysphagia, and reflux-like symptoms. Histologically, eosinophilic esophagitis is identifiable by a dense epithelial eosinophilic infiltrate. Experimental modeling and clinical studies over the last decade have greatly improved mechanistic insights and led to improvements in clinical understanding and the assessment of therapeutic options for patients and their clinicians who manage this disease. Here, we review the clinicopathologic diagnostic criteria and our understanding of eosinophilic esophagitis as an allergic disease with genetic and immunological components. We present studies defining the importance of the epithelial barrier and the concept of barrier dysfunction as an initiating or perpetuating factor for this disease. We discuss the relationship between the symptoms of dysphagia and feeding dysfunction, our current knowledge of the underlying pathophysiologic mechanisms, and advances in clinical assessment of esophageal distensibility and narrowing in eosinophilic esophagitis patients. Finally, therapeutic implications relating to the advances that have led to our current understanding of the pathophysiology of eosinophilic esophagitis are explored.

Monoclonal Antibodies for Treatment of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus affecting both children and adults, with debilitating and progressive symptoms. EoE has shown an explosive epidemiological rise in the past few decades. Many patients experience a poor level of disease control despite maximal use of available guideline-based therapies, which seriously hampers their quality of life. Diet restrictions and systemic and topical corticosteroids are the current mainstays of EoE therapy, but are associated with significant efficacy, treatment compliance, and safety issues such as oral or esophageal candidiasis, growth retardation, osteopenia, osteoporosis, glucose intolerance, and cataract formation. As EoE is a chronic inflammatory disease, immune cells and cytokines are responsible for the inflammatory response and symptoms. Monoclonal antibodies specifically targeting these pathophysiologic effectors offer more potent relief of histologic and clinical disease features while keeping off-target adverse effects to a minimum. Herein, we have reviewed the current evidence regarding efficacy and safety of monoclonal antibodies including mepolizumab (anti-IL-5), reslizumab (anti-IL-5), QAX576 (anti-IL-13), omalizumab (anti-immunoglobulin-E), and infliximab (anti-TNF-α) in treatment of EoE. Our review indicates that although the use of monoclonal antibodies for EoE treatment is safe with limited and reversible adverse events, however, it is not yet possible to reach a final verdict on the efficacy of mAbs in EoE. Future well-designed studies are needed to clarify the exact role of mAbs in EoE.

TGF-β1 alters esophageal epithelial barrier function by attenuation of claudin-7 in eosinophilic esophagitis

Barrier dysfunction has been implicated in the pathophysiology of eosinophilic esophagitis (EoE). Transforming growth factor-β1 (TGF-β1), a potent pleiotropic molecule, is increased in EoE; however, no study has evaluated its influence on esophageal epithelial barrier. We hypothesized that TGF-β1 regulates barrier dysfunction in EoE. We aimed to determine the role of TGF-β1 in the epithelial barrier in models of EoE. To examine the impact of TGF-β1 on esophageal barrier, immortalized human esophageal epithelial (EPC2-hTERT) cells were exposed to TGF-β1 during the three-dimensional air-liquid interface (3D-ALI) model in vitro. TGF-β1 exposure diminished EPC2-hTERT barrier function as measured by transepithelial electrical resistance (TEER) and 3 kDa Fluorescein isothiocyanate dextran paracellular flux (FITC Flux), and hematoxylin and eosin (H&E) assessment revealed prominent cellular separation. In analysis of epithelial barrier molecules, TGF-β1 led to the specific reduction in expression of the tight-junction molecule, claudin-7 (CLDN7), and this was prevented by TGF-β-receptor I inhibitor. Short hairpin ribonucleic acid (shRNA)-mediated CLDN7 knockdown diminished epithelial barrier function, whereas CLDN7 overexpression resulted in protection from TGF-β1-mediated barrier dysfunction. In pediatric EoE biopsies CLDN7 expression was decreased and altered localization was observed with immunofluorescence analysis, and the TGF-β1 downstream transcription factor, phosphorylated SMAD2/3 (pSMAD2/3), was increased. Our data suggest that TGF-β1 participates in esophageal epithelial barrier dysfunction through CLDN7 dysregulation.

Esophageal 3D Culture Systems as Modeling Tools in Esophageal Epithelial Pathobiology and Personalized Medicine

The stratified squamous epithelium of the esophagus shows a proliferative basal layer of keratinocytes that undergo terminal differentiation in overlying suprabasal layers. Esophageal pathologies, including eosinophilic esophagitis, gastroesophageal reflux disease, Barrett's esophagus, squamous cell carcinoma, and adenocarcinoma, cause perturbations in the esophageal epithelial proliferation-differentiation gradient. Three-dimensional (3D) culture platforms mimicking in vivo esophageal epithelial tissue architecture ex vivo have emerged as powerful experimental tools for the investigation of esophageal biology in the context of homeostasis and pathology. Herein, we describe types of 3D culture that are used to model the esophagus, including organotypic, organoid, and spheroid culture systems. We discuss the development and optimization of various esophageal 3D culture models; highlight the applications, strengths, and limitations of each method; and summarize how these models have been used to evaluate the esophagus under homeostatic conditions as well as under the duress of inflammation and precancerous/cancerous conditions. Finally, we present future perspectives regarding the use of esophageal 3D models in basic science research as well as translational studies with the potential for personalized medicine.

The Esophageal Organoid System Reveals Functional Interplay Between Notch and Cytokines in Reactive Epithelial Changes

BACKGROUND & AIMS

Aberrations in the esophageal proliferation-differentiation gradient are histologic hallmarks in eosinophilic esophagitis (EoE) and gastroesophageal reflux disease. A reliable protocol to grow 3-dimensional (3D) esophageal organoids is needed to study esophageal epithelial homeostasis under physiological and pathologic conditions.

METHODS

We modified keratinocyte-serum free medium to grow 3D organoids from endoscopic esophageal biopsies, immortalized human esophageal epithelial cells, and murine esophagi. Morphologic and functional characterization of 3D organoids was performed following genetic and pharmacologic modifications or exposure to EoE-relevant cytokines. The Notch pathway was evaluated by transfection assays and by gene expression analyses in vitro and in biopsies.

RESULTS

Both murine and human esophageal 3D organoids displayed an explicit proliferation-differentiation gradient. Notch inhibition accumulated undifferentiated basal keratinocytes with deregulated squamous cell differentiation in organoids. EoE patient-derived 3D organoids displayed normal epithelial structure ex vivo in the absence of the EoE inflammatory milieu. Stimulation of esophageal 3D organoids with EoE-relevant cytokines resulted in a phenocopy of Notch inhibition in organoid 3D structures with recapitulation of reactive epithelial changes in EoE biopsies, where Notch3 expression was significantly decreased in EoE compared with control subjects.

CONCLUSIONS

Esophageal 3D organoids serve as a novel platform to investigate regulatory mechanisms in squamous epithelial homeostasis in the context of EoE and other diseases. Notch-mediated squamous cell differentiation is suppressed by cytokines known to be involved in EoE, suggesting that this may contribute to epithelial phenotypes associated with disease. Genetic and pharmacologic manipulations establish proof of concept for the utility of organoids for future studies and personalized medicine in EoE and other esophageal diseases.

Pathophysiology of Eosinophilic Esophagitis

Eosinophilic esophagitis is an emerging disease that is distinguished from gastroesophageal reflux disease by the expression of a unique esophageal transcriptome and the interplay of early life environmental factors with distinct genetic susceptibility elements at 5q22 (TSLP) and 2p23 (CAPN14). Rare genetic syndromes have uncovered the contribution of barrier disruption, mediated in part by defective desmosomes and dysregulated transforming growth factor beta production and signaling, to eosinophilic esophagitis pathophysiology. Experimental modeling has defined a cooperative role of activated eosinophils, mast cells, and the cytokines IL-5 and IL-13, mediated by allergic sensitization to multiple foods. Understanding these processes is opening the way to better treatment based on disrupting allergic inflammatory and type 2 cytokine-mediated responses, including anti-cytokine therapeutics and dietary therapy.

Prognostic significance of the epithelial-mesenchymal transition factor zinc finger E-box-binding homeobox 2 in esophageal squamous cell carcinoma

Zinc finger E-box-binding homeobox 2 (ZEB2) has been reported to mediate epithelial-mesenchymal transition (EMT) and disease progression in several cancer types. However, the expression of ZEB2 in esophageal squamous cell carcinoma (OSCC) and its association with prognosis remains unclear. In the present study, a tissue microarray and immunohistochemistry were used to investigate ZEB2 and epithelial (E-)cadherin expression in OSCC tissues (n=218) and peritumoral esophageal tissues (POT; n=60). There was a significantly increased incidence of positive ZEB2 expression in OSCC tissues compared with the expression in POTs (P<0.012). By contrast, the incidence of positive E-cadherin expression in OSCC tissues was significantly decreased compared with the expression in POTs (P<0.004). ZEB2 expression in OSCC was associated with a number of clinicopathological factors, and it was also an independent predictive factor for shorter overall survival time (P<0.001). Overall, ZEB2 may promote OSCC metastasis and is a potential prognostic marker for malignancy.

Autophagy mediates epithelial cytoprotection in eosinophilic oesophagitis

OBJECTIVE

The influence of eosinophilic oesophagitis (EoE)-associated inflammation upon oesophageal epithelial biology remains poorly understood. We investigated the functional role of autophagy in oesophageal epithelial cells (keratinocytes) exposed to the inflammatory EoE milieu.

DESIGN

Functional consequences of genetic or pharmacological autophagy inhibition were assessed in endoscopic oesophageal biopsies, human oesophageal keratinocytes, single cell-derived ex vivo murine oesophageal organoids as well as a murine model recapitulating EoE-like inflammation and basal cell hyperplasia. Gene expression, morphological and functional characterisation of autophagy and oxidative stress were performed by transmission electron microscopy, immunostaining, immunoblotting, live cell imaging and flow cytometry.

RESULTS

EoE-relevant inflammatory conditions promoted autophagy and basal cell hyperplasia in three independent murine EoE models and oesophageal organoids. Inhibition of autophagic flux via chloroquine treatment augmented basal cell hyperplasia in these model systems. Oesophageal keratinocytes stimulated with EoE-relevant cytokines, including tumour necrosis factor-α and interleukin-13 exhibited activation of autophagic flux in a reactive oxygen species-dependent manner. Autophagy inhibition via chloroquine treatment or depletion of Beclin-1 or ATG-7, augmented oxidative stress induced by EoE-relevant stimuli in murine EoE, oesophageal organoids and human oesophageal keratinocytes. Oesophageal epithelia of paediatric EoE patients with active inflammation displayed increased autophagic vesicle content compared with normal and EoE remission subjects. Functional flow cytometric analysis revealed autophagic flux in human oesophageal biopsies.

CONCLUSIONS

Our findings reveal for the first time that autophagy may function as a cytoprotective mechanism to maintain epithelial redox balance and homeostasis under EoE inflammation-associated stress, providing mechanistic insights into the role of autophagy in EoE pathogenesis.

Control of inflammation decreases the need for subsequent esophageal dilation in patients with eosinophilic esophagitis

It is unknown if successful control of esophageal inflammation in eosinophilic esophagitis (EoE) decreases the need for subsequent esophageal dilation. We aimed to determine whether histologic response to topical steroid treatment decreases the likelihood and frequency of subsequent esophageal dilation. We conducted a retrospective cohort study. Patients with an incident diagnosis of EoE were included if they had an initial esophageal dilation, received topical steroids, and had a subsequent endoscopy with biopsies. The number of dilations performed in each group was determined, and histologic responders (<15 eos/hpf) were compared to nonresponders. The 55 EoE patients included (27 responders and 28 nonresponders) underwent a mean of 3.0 dilations over a median follow-up of 19 months. Responders required fewer dilations than nonresponders (1.6 vs. 4.6, P = 0.03), after adjusting for potential confounders. Despite undergoing significantly fewer dilations, responders achieved a similar increase in esophageal diameter with dilation (4.9 vs. 5.0 mm; P = 0.92). In EoE patients undergoing esophageal dilation at baseline, control of inflammation with topical steroids was associated with a 65% decrease in the number of subsequent dilations to maintain the same esophageal caliber. This suggests that inflammation control is an important goal in patients with fibrostenotic changes of EoE.

Eosinophilic Esophagitis-Associated Chemical and Mechanical Microenvironment Shapes Esophageal Fibroblast Behavior

OBJECTIVES

Eosinophilic esophagitis (EoE) is an immune-mediated allergic disease characterized by progressive esophageal dysmotility and fibrotic stricture associated with chronic esophageal fibroblast activation. It remains unknown how esophageal fibroblasts respond to EoE-relevant matrix stiffness or inflammatory cytokines.

METHODS

Immunofluorescence was used to evaluate α-smooth muscle actin (α-SMA) expression in endoscopic esophageal biopsies. Primary esophageal fibroblasts from adult and pediatric patients with or without EoE were exposed to transforming growth factor (TGF)β to determine gene expression, collagen-matrix contractility, and cytoskeletal organization. The influence of matrix stiffness upon fibroblast behavior was assessed on the engineered surface of polyacrylamide gels with varying stiffness. Fibroblast traction forces were measured using microfabricated-post-array-detectors.

RESULTS

EoE esophageal fibroblasts had enhanced α-SMA expression. TGFβ not only stimulated enhanced fibroblast-specific gene expression but also promoted fibroblast-mediated collagen-matrix contraction, despite disease state or age of patients as the origin of cells. Unlike conventional monolayer cell, culture conditions using plastic surface (1 GPa) that activates fibroblasts constitutively, our engineered platforms recapitulating physiologically relevant stiffness (1-20 kPa) revealed that matrix stiffness defines the extent of α-SMA expression, intracellular collagen fibril organization, SMAD3 phosphorylation, and fibroblast traction force.

CONCLUSIONS

Matrix stiffness may critically influence TGFβ-mediated gene expression and functions of esophageal fibroblasts ex vivo independent of age and disease conditions. These findings provide a novel insight into the pathogenesis of fibrostenotic disease in EoE.

Development of an In Vitro Assay to Evaluate Contractile Function of Mesenchymal Cells that Underwent Epithelial-Mesenchymal Transition

Fibrosis is often involved in the pathogenesis of various chronic progressive diseases such as interstitial pulmonary disease. Pathological hallmark is the formation of fibroblastic foci, which is associated with the disease severity. Mesenchymal cells consisting of the fibroblastic foci are proposed to be derived from several cell sources, including originally resident intrapulmonary fibroblasts and circulating fibrocytes from bone marrow. Recently, mesenchymal cells that underwent epithelial-mesenchymal transition (EMT) have been also supposed to contribute to the pathogenesis of fibrosis. In addition, EMT can be induced by transforming growth factor β, and EMT can be enhanced by pro-inflammatory cytokines like tumor necrosis factor α. The gel contraction assay is an ideal in vitro model for the evaluation of contractility, which is one of the characteristic functions of fibroblasts and contributes to wound repair and fibrosis. Here, the development of a gel contraction assay is demonstrated for evaluating contractile ability of mesenchymal cells that underwent EMT.

Eosinophilic Esophagitis in Two Patients with Systemic Sclerosis

The gastrointestinal tract (GIT) is the most common extracutaneous organ system damaged in systemic sclerosis (SSc) and is the presenting feature in 10% of patients. The esophagus as the portion of the GIT is the most commonly affected and there is an association of gastroesophageal reflux (GER) with SSc interstitial lung disease (ILD). Thus, an aggressive treatment for GER is recommended in all SSc patients with ILD; however, it is recognized that a long-term benefit to this treatment is needed to understand its impact. In this case report we discuss the presence of eosinophilic esophagitis (EoE) in two SSc patients and discuss the role for early EGD in SSc patients with moderate-severe GER symptoms for tissue study. Assessment of esophageal biopsy specimens for the presence of eosinophils and possibly ANA can help elucidate disease pathogenesis and direct therapy, as the presence of EoE in SSc has important management considerations, particularly with regards to dietary modification strategies.

The esophageal biopsy "pull" sign: a highly specific and treatment-responsive endoscopic finding in eosinophilic esophagitis (with video)

BACKGROUND AND AIMS

Esophageal biopsy specimens from patients with eosinophilic esophagitis (EoE) can feel firm, with resistance felt when pulling the forceps to obtain the tissue sample. We aimed to assess the diagnostic utility of the esophageal biopsy "pull" sign and determine its histologic associations and response to treatment.

METHODS

This was a prospective cohort study of adults undergoing outpatient upper endoscopy. Cases of EoE were diagnosed per consensus guidelines, and patients were subsequently treated with either topical steroids or dietary elimination. Control subjects were individuals who did not have EoE. The frequency of the esophageal biopsy "pull" sign was assessed in EoE patients and controls, and diagnostic metrics were calculated. The "pull" sign was also reassessed in patients after therapy.

RESULTS

A total of 83 EoE patients and 121 control subjects were included. Sixty-three EoE patients (76%) were "pull" sign positive compared with just 2 control subjects (2%; P < .001), corresponding to a sensitivity and specificity of 76% and 98%, positive and negative predictive values of 97% and 86%, and positive and negative likelihood ratios of 45.9 and 0.245, respectively. The "pull" sign was the strongest endoscopic predictor of EoE case status at baseline and was less frequent after successful treatment (20% vs 79%; P < .001).

CONCLUSIONS

The "pull" sign is highly specific for EoE and is rarely seen in non-EoE control subjects. In patients with EoE who respond to treatment, the "pull" sign often resolves. The "pull" sign may be a simple and easily obtained measure of esophageal remodeling.

Eosinophilic Esophagitis

Once considered a rare condition, eosinophilic esophagitis is now one of the most common conditions diagnosed during the assessment of feeding problems in children and during the evaluation of dysphagia and food impaction in adults. The entity exists worldwide but has been most extensively studied in Western countries, where its prevalence has been estimated to be 0.4% among all children and adults. Whether eosinophilic esophagitis is truly a new disease or simply a recently recognized one is uncertain. In this review, we consider the diagnostic criteria, pathophysiological and clinical features, and treatment of this increasingly prevalent disease.

Translating new developments in eosinophilic esophagitis pathogenesis into clinical practice

OPINION STATEMENT

New developments in eosinophilic esophagitis (EoE) pathogenesis are shaping our current therapeutic and management strategies. EoE is a chronic allergic inflammatory disease with progression to fibrostenotic disease. The disease warrants early diagnosis and long-term maintenance therapy. The diagnosis of EoE should be based on the concept of an allergy-mediated disease with esophageal dysfunction and esophageal eosinophilia. Recent findings suggest that proton pump inhibitor (PPI)-responsive esophageal eosinophilia (PPI-REE) is likely a continuum of EoE or a similar T-helper 2 (Th2)-mediated allergic process. PPIs have therapeutic properties that can benefit both gastroesophageal reflux disease (GERD) and EoE. Therefore, PPIs should be considered not a diagnostic tool but, rather, a therapeutic option for EoE. If patients are PPI nonresponsive, then dietary therapy or steroid therapy should be considered. Dilation can be reserved as adjuvant therapy for severe fibrostenotic lesions.

Recent advances in the pathological understanding of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic allergen-mediated inflammatory disease of the esophagus. This inflammation leads to feeding difficulties, failure to thrive and vomiting in young children, and causes food impaction and esophageal stricture in adolescents and adults. In the 20 years since EoE was first described, we have gained a great deal of knowledge regarding the genetic predisposition of disease, the inflammatory milieu associated with EoE and the long-term complications of chronic inflammation. Herein, we summarize the important breakthroughs in the field including both in vitro and in vivo analysis. We discuss insights that we have gained from large-scale unbiased genetic analysis, a multitude of genetically and chemically altered mouse models of EoE and most importantly, the results of clinical trials of various pharmacologic agents. Understanding these successes and failures may be the key to developing more effective therapeutic strategies.