Eosinophilic oesophagitis (EoE) is a chronic inflammatory disease afflicting the oesophagus and causing lifelong morbidity. Over the last few decades, EoE has significantly increased in prevalence with oral corticosteroids, such as budesonide, being the current mainstay of therapy. Tacrolimus is an immunomodulatory drug with anti-inflammation properties that is not on the conventional therapeutic regimen for EoE but offers a promising alternative non-steroidal treatment for patients who do not respond to diet elimination, proton pump inhibitors (PPIs), or corticosteroids. This study aims to investigate and compare the accumulation between locally delivered budesonide and tacrolimus, using an ex vivo porcine oesophageal model of EoE, over a range of contact times up to 30 min. Budesonide and tacrolimus were solubilised in a cosolvent and surfactant formulation to maintain solvation capacity in artificial saliva. Injured and non-injured (control) porcine oesophageal mucosa were used as surrogates to represent EoE and healthy oesophageal mucosa in humans, respectively, due to the highly similar physiological architecture of the oesophagus. EoE-mimicking oesophageal damage was chemically induced by pancreatic enzymes and bile salts known to dilate intercellular spaces typically observed in EoE pathophysiology where tight junction damage was represented by an irreversible drop in transepithelial electrical resistance (TEER). Whole tissue and basolateral accumulation of budesonide and tacrolimus were quantified after 30 min using liquid chromatography tandem mass spectrometry (LC-MS/MS). Tacrolimus yielded a significant increase (p < 0.05) in injured tissue accumulation (approximately two-fold) in comparison to non-injured tissue, while budesonide yielded no significant difference (p > 0.05) in tissue accumulation between the two. Considering the significant accumulation of tacrolimus in this ex vivo porcine model of EoE, using injury-induced porcine oesophageal mucosa, this study suggests the use of tacrolimus as a targeted local therapy for the treatment of EoE.

The pathophysiology of eosinophilic esophagitis (EoE) is associated with a strong heritability and esophageal-specific genetic variants. Patients with esophageal atresia (EA) may be at higher risk of developing EoE considering the recently discovered genetic similarities between these disorders. This study aimed to identify genetic mutations associated with EoE, explore their potential role in susceptibility to concurrent EA, and evaluate the relationship between these mutations, clinical course, and treatment response.

Whole-exome sequencing was performed to identify the potential genomic regions associated with an increased risk of these disorders, and the analysis was expanded for candidate genes.

A total of 35 cases (EA + EoE +; n = 7) were included. Pathogenic mutations in genes associated with EoE were identified in 2 cases, while likely pathogenic variants were identified in 5 cases. No polymorphisms were detected in 5 cases. Variants of uncertain significance (VUS) were identified in genes associated with EoE in 18 cases and in candidate genes in 7 cases. Patients with VUS exhibited a high percentage of associated EA, increased rates of atopy, and a notable response to treatment. The duration of the clinical response was significantly longer in individuals without genetic mutations (p-value:0.006). Among the isolated EoE cases, 50% had variants in genes previously associated with EoE, whereas in EA + EoE + cases, this rate increased to 71%, suggesting a stronger genetic predisposition in EA + EoE + cases.

Our study highlights the role of genetic mutations in the etiology of EoE. The identification of novel gene variants and new insights into etiopathogenesis are anticipated to enhance diagnosis, screening, and treatment strategies.

Novel treatments are needed for eosinophilic oesophagitis. Etrasimod is an oral, once-daily, selective sphingosine 1-phosphate (S1P)1,4,5 receptor modulator in development for the treatment of immune-mediated inflammatory diseases. We assessed efficacy and safety of etrasimod versus placebo in adults with eosinophilic oesophagitis.

In this double-blind, randomised, phase 2 trial, patients aged 18-65 years with a previous diagnosis of eosinophilic oesophagitis and histologically active disease from 64 clinical sites (in Australia, Belgium, Spain, Switzerland, and the USA) were randomly assigned (3:3:2) using an interactive web response system to receive oral etrasimod 2 mg or 1 mg or matching placebo for 24 weeks (centrally randomly assigned and double-blind; placebo-controlled period); they continued assigned etrasimod doses or were randomly assigned (1:1) from placebo to etrasimod 2 mg or 1 mg for 28 weeks (extension period). Randomisation was stratified by history of oesophageal dilation and concurrent proton pump inhibitor therapy. The full analysis set and safety set consisted of all randomly assigned patients who received at least one study treatment dose. The primary endpoint was percentage change from baseline in oesophageal peak eosinophil count (PEC) at week 16. Safety was assessed up to week 52. Patients were analysed according to treatment received in the placebo-controlled period and extension period. The trial was registered with ClinicalTrials.gov, NCT04682639, and EudraCT, 2020-003226-23; completed on June 30, 2023.

Between Dec 15, 2020, and May 27, 2022, 41 patients were randomly assigned to etrasimod 2 mg (20 [49%] females and 21 [51%] males), 39 to etrasimod 1 mg (17 [44%] females and 22 [56%] males), and 28 to placebo (14 [50%] females and 14 [50%] males). 85 (79%) of 108 patients completed the double-blind period, entering the extension period. Median percentage changes from baseline in PEC at week 16 were -58·4% (IQR -86·2 to -26·3) for etrasimod 2 mg (p=0·010 vs placebo), -39·4% (-71·1 to 79·0) for etrasimod 1 mg (p=0·29 vs placebo) and -21·5% (-57·2 to 55·4) for placebo. In the placebo-controlled period, the most common treatment-emergent adverse events were gastrointestinal disorders (11 [27%] of 41 patients in the etrasimod 2 mg group, 13 [33%] of 39 patients in the etrasimod 1 mg group, and 14 [50%] of 28 patients in the placebo group). Bradycardia events, reported by three patients (two [5%] patients in the etrasimod 2 mg group and one [4%] in the placebo group) in the placebo-controlled period, were mild or moderate in severity. No serious treatment-emergent adverse events or deaths occurred.

Etrasimod led to sustained histological and endoscopic improvements in eosinophilic oesophagitis over 52 weeks, symptom improvement in patients without dilation, and was well tolerated. This trial provides the first evidence that targeting the S1P pathway can improve disease activity in patients with eosinophilic oesophagitis and that S1P receptor modulation is a viable treatment target for this disease.

Pfizer.

Eosinophilic esophagitis (EoE) is a chronic disease which clinically presents with symptoms related to esophageal dysfunction, while pathologically it is characterized by eosinophilic infiltration of esophageal epithelium. Most patients with EoE present with food and/or inhalant allergy symptoms. The results of animal model studies and genetic studies, as well as the efficacy of elimination diets in managing the symptoms, suggest an atopic background of the disease. The aim of this study was to evaluate the prevalence of EoE in a group of patients with upper gastrointestinal symptoms and food and/or inhalant allergies and to assess the influence of drugs used in type I allergies on the results of endoscopic, histopathological, and immunohistochemical tests. Methods: This was a prospective observational study. Patients with inhalant/food allergies and upper esophageal symptoms constituted the study group while patients without allergies who were diagnosed with dyspepsia or irritable bowel syndrome constituted the control group. All study group subjects underwent allergy testing, including prick testing and blood tests. All participants underwent a gastroscopy with specimen collection. Esophageal specimens were stained for eotaxin-1 and desmoglein-1. Results: Based on histopathology results, eosinophilic esophagitis was found in 9 of the 73 patients from the study group. All patients with EoE presented with multimorbidity and were diagnosed with at least one allergic disease in addition to EoE. Positive staining for CCL-11 was found in 56 (78%) patients in the study group, including all patients with EoE while only 3 (17%) individuals from the control group showed positive staining. The presence of DSG-1 in esophageal specimens was detected in 6 (7%) subjects from the study group in contrast to 14 (78%) subjects from the control group. DSG-1 was not found in any of the specimens of patients diagnosed with EoE. Conclusions: EoE is a rare disease, usually accompanied by allergic multimorbidity. Positive staining for eotaxin-1 and negative staining for desmoglein-1 in patients with esophageal symptoms and allergies but who did not meet EoE diagnostic criteria could be indicative of subclinical course of the disease or a masking effect of corticosteroids. It is now vitally important for both researchers and practicing clinicians to recognize that eosinophilic esophagitis (EoE) is not a homogeneous disease but rather consists of multiple subtypes (phenotypes). The so-called "classic" form of EoE-defined by current diagnostic criteria as the presence of more than 15 eosinophils per high power field on histopathological examination-appears to represent only the tip of the iceberg. There is an urgent need for further research in order to refine endoscopic techniques, expand the scope of histopathological assessments, and identify novel biomarkers to better define the distinct phenotypes of eosinophilic esophagitis.

The synthetic cortisol analog budesonide (BUD) is an essential drug employed to manage chronic inflammatory diseases in humans, mainly those involving gastroenteric and airway mucosa, such as rhinitis, laryngitis, bronchitis, esophagitis, gastritis, and colitis, with high levels of success. As a glucocorticoid, BUD prevents the expression of pro-inflammatory cytokines/chemokines and the recruitment of immune cells into the inflamed mucosa. However, emerging evidence indicates that BUD, unlike classical glucocorticoids, is also a potent modulator of stem and cancer cell behavior/plasticity. Certainly, BUD stabilizes cell-cell adhesions, preventing embryonic stem cell differentiation and inhibiting the development of 3D gastruloids. In addition, BUD inhibits the motile/invasive propensity of different cancer cells, including breast, lung, and pancreatic cancer. Finally, it prevents the infection of positive single-stranded human-infecting RNA viruses such as SARS-CoV-2. At a molecular level, BUD induces epigenetic changes and modifies the transcriptome of epithelial, stem, and cancer cells, providing molecular support to the immune cell-independent activity of BUD. Here, we performed an in-depth review of these unexpected activities of BUD, identified by unbiased drug screening programs, and we emphasize the molecular mechanisms modulated by this efficacious drug that deserve further research.

Eosinophilic esophagitis (EoE) is a chronic, inflammatory, and antigen-driven disease of the esophagus. Total transcriptome data revealed alterations in the endocannabinoid system, in particular, down-regulation of monoacylglycerol lipase (MGL) in biopsies of patients with active EoE. We investigated the consequence of MGL down-regulation in mucosal biopsies of patients, and its implications for EoE development, such as recruitment of eosinophils.

Levels of MGL substrate 2-arachidonoylglycerol, MGL enzyme activity, and MGL colocalization with epithelial cells were determined in mucosal esophageal biopsies of patients with EoE. Supernatant of human primary esophageal epithelial cells was used to determine eosinophil migration and activation. An inducible mouse model of EoE was used to test MGL inhibition and cannabinoid (CB) receptor antagonism in vivo.

MGL expression in esophageal epithelial cells from patients with active EoE is decreased, whereas 2-arachidonoylglycerol is increased compared with control subjects. Inhibition of MGL in epithelial cells leads to a proinflammatory phenotype capable of attracting eosinophils via CB2. Similarly, the EoE mouse model indicates that absence of MGL results in higher eosinophil infiltration. Targeting CB2 reduced the number of infiltrating eosinophils in the esophagi of mice.

This study is the first of its kind to investigate the involvement of altered expression of endocannabinoid system components in EoE, and partly explains recent findings of more inflammatory features post EoE-treatment in cannabis users. Our findings could pave the way for research into alternative treatment options for EoE and call for caution regarding the use of cannabinoids in EoE.

Eosinophilic esophagitis (EoE) is a chronic TH2-associated inflammatory disorder triggered by food allergens, resulting in esophageal dysfunction through edema, fibrosis, and tissue remodeling. The role of epithelial remodeling in EoE pathogenesis is critical but not fully understood.

We investigated the role of epithelial IKKβ/NF-κB signaling in EoE pathogenesis using a mouse model with conditional Ikkβ knockout in esophageal epithelial cells (IkkβEEC-KO).

EoE was induced in IkkβEEC-KO mice through skin sensitization with MC903/ovalbumin followed by intraesophageal ovalbumin challenge. Histologic and transcriptional analyses were performed to assess EoE features. Single-cell RNA sequencing was used to profile esophageal mucosal cell populations and gene expression changes.

IkkβEEC-KO/EoE mice exhibited hallmark EoE features, including eosinophil infiltration, intraepithelial eosinophils, microabscesses, basal cell hyperplasia, and lamina propria remodeling. RNA sequencing revealed significant alterations in IKKβ/NF-κB signaling pathways, with decreased expression of RELA and increased expression of IKKβ-negative regulators. Sequencing analyses identified disrupted epithelial differentiation and barrier integrity alongside increased type 2 immune responses and peptidase activity.

Loss of epithelial IKKβ signaling exacerbates EoE pathogenesis, highlighting the critical role of this pathway in maintaining epithelial homeostasis and preventing allergic inflammation. The IkkβEEC-KO/EoE mouse model closely mirrors human EoE, providing a valuable tool for investigating disease mechanisms and therapeutic targets. This model can facilitate the development of strategies to prevent chronic inflammation and tissue remodeling in EoE.

Dysphagia in pemphigus vulgaris (PV) patients should not be attributed solely to PV. Eosinophilic esophagitis (EoE) can coexist and requires endoscopic evaluation and biopsy for accurate diagnosis. Both conditions may share underlying immune mechanisms, emphasizing the importance of precise diagnosis and targeted treatment.

The respiratory epithelium maintains the barrier against inhaled harmful agents. When barrier failure occurs, as in several respiratory diseases, acute or chronic inflammation leading to destructive effects and exacerbations can occur. Macrolides are used to treat a spectrum of infections but are also known for off-label use. Some macrolides, particularly azithromycin (AZM), reduce exacerbations in chronic obstructive pulmonary disease (COPD), whereby its efficacy is thought to be due to its effects on inflammation and oxidative stress. In vitro data indicate that AZM reduces epithelial barrier failure, evidenced by increased transepithelial electrical resistance (TEER). Here, we compared the effects of macrolides on differentiation and barrier integrity in VA10 cells, a bronchial epithelial cell line for 14 and 21 days. Erythromycin, clarithromycin, roxithromycin, AZM, solithromycin, and tobramycin (an aminoglycoside) were analyzed using RNA sequencing, barrier integrity assays, and immunostaining to evaluate effects on the epithelium. All macrolides affected the gene expression of pathways involved in epithelial-to-mesenchymal transition, metabolism, and immunomodulation. Treatment with AZM, clarithromycin, and erythromycin raised TEER and induced phospholipid retention. AZM treatment was distinct in terms of enhancement of the epithelial barrier, retention of phospholipids, vesicle build-up, and its effect on gene sets related to keratinocyte differentiation and establishment of skin barrier.

Background/Objectives: Evaluation of stem cell, keratin, retinoic acid metabolism markers and non-coding micro-RNAs (miRNAs) in conjunctival and corneal samples of patients with epithelial basal membrane dystrophy (EBMD), Salzmann nodular degeneration (SND), pterygium and congenital aniridia (CA), to detect similarities and differences in their pathogenesis. Methods: Impression cytology (IC) samples and corneal epithelial samples (CEs) of patients with EBMD, SND, pterygium, congenital aniridia, and healthy control subjects have been analyzed. The IC samples were subjected to qPCR, and the epithelial samples were subjected to qPCR and WB. Limbal epithelial stem cell markers, keratins, retinoic acid metabolism markers, and miRNAs were analyzed. Results: In conjunctival IC samples, PAX6 mRNA expression was significantly lower in EBMD, SND, pterygium, and CA compared to healthy controls (p ≤ 0.02). KRT13 mRNA expression was significantly higher in EBMD, SND, and pterygium (p ≤ 0.018), and FABP5 was increased in pterygium samples (p = 0.007). MiRNA-138-5p was significantly higher in aniridia samples than in normal controls (p = 0.037). In corneal epithelial samples, PAX6 protein, DSG1 mRNA and protein, miRNA-138-5p, and miR-204-5p expression were significantly lower in EBMD, SND, and pterygium samples than in controls (p ≤ 0.02). ALDHA1 mRNA expression was significantly lower (p < 0.0001), and FABP5 mRNA expression was significantly higher (p = 0.014) in pterygium samples than in controls. Conclusions: PAX6, DSG1, miR-138-5p, and miR-204-5p expression is decreased in the corneal epithelium of epithelial basal membrane dystrophy, Salzmann nodular degeneration, and pterygium subjects. In addition, there is a dysregulation of markers of the retinoic acid signaling pathway, such as ADH1A1 and FABP5, in the corneal epithelium of pterygium subjects. These changes may offer therapeutic targets in the treatment of these ocular surface diseases.

Patients with eosinophilic esophagitis (EoE) require long-lasting resolution of inflammation to prevent fibrostenosis and dysphagia. However, the dissociation between symptoms and histologic improvement suggests persistent molecular drivers despite histologic remission.

We characterized persisting molecular alterations in pediatric patients with EoE using tissue transcriptomics and proteomics.

Esophageal biopsy samples (n = 247) collected prospectively during 189 endoscopies from pediatric patients with EoE (n = 36, up to 11 follow-up endoscopies) and pediatric controls (n = 44, single endoscopies) were subjected to bulk transcriptomics (n = 96) and proteomics (n = 151). Intercellular junctions (desmoglein-1/3, desmoplakin, E-cadherin) and epithelial-to-mesenchymal transition (vimentin:E-cadherin ratio) were assessed by immunofluorescence staining.

Active EoE (≥15 eosinophils per high-power field [eos/hpf]), inactive EoE (<15 eos/hpf), and deep-remission EoE (0 eos/hpf) were diagnosed in 107 of 185, 78 of 185, and 41 of 185 biopsy samples, respectively. Among the dysregulated genes (up-/downregulated 310/112) and proteins (up-/downregulated 68/16) between active EoE and controls, 17 genes, and 6 proteins remained dysregulated in inactive EoE. Using persistently upregulated genes (n = 9) and proteins (n = 3) only, such as ALOX15, CXCL1, CXCL6, CTSG, CDH26, PRRX1, CLC, EPX, and periostin (POSTN), was sufficient to separate inactive EoE and deep-remission biopsy samples from control tissue. While 32 differentially expressed genes persisted in deep-remission EoE compared to controls, the proteome normalized except for persistently upregulated POSTN. Epithelial-to-mesenchymal transition normalized in inactive EoE, whereas desmosome recovery remained impaired as a result of desmoglein-1 downregulation.

The analysis of molecular changes shows persistent EoE-associated esophageal dysregulation despite histologic remission. These data expand our understanding of inflammatory processes and possible mechanisms that underlie tissue remodeling in EoE.

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory condition of the esophagus characterized by eosinophilic infiltration, and hallmark symptoms of esophageal dysfunction such as dysphagia and food impaction. Over the past three decades, EoE has been recognized as a distinct clinical entity, distinguished from gastroesophageal reflux disease (GERD) through advancements in diagnostic techniques, particularly endoscopy with biopsy. The rising global prevalence of EoE reflects enhanced diagnostic awareness, evolving criteria, and environmental along with lifestyle changes. The etiology of EoE is multifactorial, involving genetic predispositions, immune dysregulation, the gut microbiome, and environmental triggers, including dietary allergens and aeroallergens. Key mechanisms include a type 2 helper T-cell (Th2)-driven immune response, epithelial barrier dysfunction, and genetic variants such as CAPN14 and TSLP. Chronic inflammation leads to tissue remodeling, fibrosis, and esophageal narrowing, contributing to disease progression and complications. Management strategies have evolved to include dietary elimination, proton pump inhibitors, topical corticosteroids, biologics, and endoscopic interventions for fibrostenotic complications. Emerging therapies targeting cytokines such as interleukin (IL)-4, IL-5, and IL-13, alongside novel diagnostic tools like the esophageal string test and Cytosponge, offer promising avenues for improved disease control and non-invasive monitoring. Long-term surveillance combining endoscopic and histological evaluations with biomarkers and non-invasive tools is critical to optimizing outcomes and preventing complications. Future research should address gaps in understanding the role of the esophageal microbiome, refine therapeutic approaches, and develop personalized strategies to improve disease management and patient quality of life.

The gut barrier encompasses several interactive, physical, and functional components, such as the gut microbiota, the mucus layer, the epithelial layer and the gut mucosal immunity. All these contribute to homeostasis in a well-regulated manner. Nevertheless, this frail balance might be disrupted for instance by westernized dietary habits, infections, pollution or exposure to antibiotics, thus diminishing protective immunity and leading to the onset of chronic diseases. Several gaps of knowledge still exist as regards this multi-level interaction. In this review we aim to summarize current evidence linking food antigens, microbiota and gut permeability interference in diverse disease conditions such as celiac disease (CeD), non-celiac wheat sensitivity (NCWS), food allergies (FA), eosinophilic gastrointestinal disorder (EOGID) and irritable bowel syndrome (IBS). Specific food elimination diets are recommended for CeD, NCWS, FA and in some cases for EOGID. Undoubtfully, each of these conditions is very different and quite unique, albeit food antigens/compounds, intestinal permeability and specific microbiota signatures orchestrate immune response and decide clinical outcomes for all of them.

Dysphagia is a common gastrointestinal complaint in the pediatric population and should raise concern for oropharyngeal as well as esophageal disorders. We describe a 7-year old patient who was admitted to the hospital for sudden onset dysphagia, abdominal pain, and decreased oral intake. Extensive evaluations including endoscopy eventually revealed herpes simplex esophagitis as well as eosinophilic esophagitis. Herpes simplex esophagitis is a rare condition in the immunocompetent population and is typically self-resolving. Eosinophilic esophagitis is a chronic, inflammatory condition characterized by esophageal eosinophilia and signs of esophageal dysfunction. The concurrent presentation of both conditions in the pediatric population has rarely been described.

Eosinophilic oesophagitis (EoE) is a chronic, immune-mediated condition characterised by eosinophilic infiltration of the oesophagus, leading to significant morbidity due to oesophageal dysfunction. The pathogenic course of EoE begins with tissue injury, marked by the intricate interplay of oesophageal barrier dysfunction and T helper 2-mediated inflammation. In response to tissue damage, a subsequent phase of tissue remodelling features a complex interaction between epithelial cells and stromal cells, aimed at tissue repair. The persistence of inflammation drives these mechanisms towards oesophageal fibrostenosis, mainly through the transforming growth factor-dependent, myofibroblast-driven accumulation of the extracellular matrix. Currently, treatment options for EoE are limited, with dietary intervention, proton pump inhibitors and oral steroids serving as first-line therapies. Dupilumab, an antiinterleukin (IL) 4/IL-13 agent, is the only biologic that has been approved by European and American regulatory authorities. However, emerging OMIC technologies significantly advance our understanding of EoE pathogenesis, revealing novel cellular and molecular mechanisms driving the disease. This progress has accelerated the identification of new therapeutic targets and agents, some already under clinical investigation, potentially expanding our therapeutic arsenal and paving the way for more personalised approaches. In this evolving landscape, artificial intelligence (AI) has shown great potential to further elaborate on the complexities of EoE heterogeneity, offering standardised tools for diagnosis, disease phenotyping, and prediction of treatment response. Though still in their early stages, integrating OMICs and AI marks a pivotal step towards precision medicine in EoE.

Nearly 80% of patients with eosinophilic esophagitis (EoE) have coexisting atopic disease, yet a subset do not. It is unclear if this lack of atopy impacts presentation or response to therapy.

To characterize the presentation and response to therapy in atopic versus nonatopic pediatric patients with EoE.

A case-control study of patients with EoE aged 6 months to 18 years (between 2018 and 2021) was performed. Patients were eligible if they had allergy testing, assessment of atopic history, and at least 1 endoscopy after initiation of treatment. Patients were considered nonatopic if they had negative allergy testing and no history of significant atopy. Response to therapy was classified as complete (peak eosinophils [eos] <15/high power field [hpf]), partial (≥15 eos/hpf but at least a 50% reduction in peak eos), or nonresponse.

A total of 168 participants were enrolled. The majority were White (n = 141, 84%), male (n = 124, 74%), and non-Hispanic (n = 158, 95%). The mean age at diagnosis was 9.4 years (standard deviation: ±4.8 years). A total of 123 participants (73.2%) were atopic, and 45 (26.8%) were nonatopic. There was no significant difference between atopic and nonatopic for most demographics or presenting symptoms. Nonatopic participants were younger than atopic participants (8.14 vs 9.8 years, P = .046). Swallowed topical corticosteroids (STC) and food elimination diets (FED) were used at a similar rate. There were no differences in treatment response between atopic/nonatopic participants in regard to STC, FED, or STC+FED.

Atopic status does not significantly impact presentation or response to treatment in pediatric EoE, but a lack of atopy may be a risk for earlier onset of disease.

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory condition that interferes with normal food ingestion, negatively impacting quality of life (QoL). Treatment options include proton pump inhibitors, corticosteroids, biologics, or dietary elimination; however, ∼1/3 of patients remain insufficiently controlled. The pathogenesis of EoE involves interleukin-13 (IL-13); therefore, targeted IL-13 inhibition may be beneficial. In a phase 2 study, cendakimab, a recombinant, humanized anti-IL-13 monoclonal antibody, significantly reduced mean esophageal eosinophil counts and improved other inflammatory parameters in patients with EoE. These findings prompted further investigation of the efficacy and safety of cendakimab in adults and adolescents with EoE in a phase 3 registrational study (NCT04753697), the design of which is presented here.

This multicenter, multinational, randomized, double-blind, placebo-controlled, 48-week, treat-through study plans to enroll 399 adults and adolescents. Randomized patients (1:1:1) will receive subcutaneous administration of 1) cendakimab 360 mg once weekly (QW) for 48 weeks, 2) cendakimab 360 mg QW for 24 weeks followed by cendakimab 360 mg every other week (with matching placebo on alternative weeks to maintain the blind) for 24 weeks, or 3) placebo QW for 48 weeks. Co-primary endpoints are mean change from baseline in dysphagia days and proportion of patients with eosinophil histologic response, defined as peak esophageal eosinophil count ≤6 per high-power field, at 24 weeks. Secondary and exploratory endpoints will address endoscopic and histologic features, QoL, safety, and pharmacokinetic assessments.

This phase 3 pivotal study will determine whether cendakimab provides an effective, safe, targeted treatment for patients with EoE.

Cell adhesion proteins localize to epithelial and endothelial cell membranes to form junctional complexes between neighboring cells or between cells and the underlying basement membrane. The structural and functional integrities of these junctions are critical to establish cell polarity and maintain tissue barrier function, while also facilitating leukocyte migration and adhesion to sites of inflammation. In addition to their adhesive properties, however, junctional proteins can also serve important noncanonical functions in inflammatory signaling and transcriptional regulation. Intriguingly, recent work has unveiled novel roles for cell adhesion proteins as both signaling initiators and downstream targets during inflammation. In this review, we discuss both the traditional functions of junction proteins in cell adhesion and tissue barrier function as well as their noncanonical signaling roles that have been implicated in facilitating diverse inflammatory pathologies.

Eosinophilic esophagitis (EoE) is a chronic allergic disease characterized by esophageal dysfunction, type-2 inflammation, and esophageal eosinophilic infiltrate. While proton pump inhibitor (PPI) therapy is commonly used for EoE management, the underlying mechanism of action remains unclear.

Air-liquid interface culture of esophageal epithelial cells was employed to investigate the impact of the PPI omeprazole on barrier integrity in IL-13-treated cultures. Epithelial chemokine secretion was assessed following stimulation with IL-13 and omeprazole, and the migration of eosinophils from healthy human donors was evaluated using 3 μm pore-sized transwells. A co-culture system of epithelial cells and eosinophils was employed to study chemokine secretion and eosinophil adhesion and activation markers.

Omeprazole treatment in the IL-13-treated air-liquid interface (ALI) model resulted in 186 differentially expressed genes and restored barrier integrity compared to ALI treated with IL-13 alone. Omeprazole treatment reduced STAT6 phosphorylation, downregulated calpain 14, and upregulated desmoglein-1 in the IL-13-treated air-liquid interface samples. IL-13-induced upregulation of Eotaxin-3, CXCL10, and periostin, but this was downregulated by omeprazole. Further, the expression of CD11b, CD18, and CD69 was lower on eosinophils from omeprazole-treated epithelial-eosinophil co-cultures, which also had lower levels of eotaxin-3, CXCL10, CCL2, and CCL4.

Omeprazole reduced the effects of IL-13 in both the epithelial air-liquid interface model and eosinophil-epithelial co-cultures, reducing barrier dysfunction, chemokine expression, and upregulation of eosinophil adhesion markers.

Eosinophilic esophagitis (EoE) and inflammatory bowel disease (IBD) are chronic inflammatory disorders of the gastrointestinal tract, with EoE predominantly provoked by food and aeroallergens, whereas IBD is driven by a broader spectrum of immunopathological and environmental triggers. This review presents a comprehensive comparison of the pathophysiological and therapeutic strategies for EoE and IBD. We examine the current understanding of their underlying mechanisms, particularly the interplay between environmental factors and genetic susceptibility. A crucial element in both diseases is the integrity of the epithelial barrier, whose disruption plays a central role in their pathogenesis. The involvement of eosinophils, mast cells, B cells, T cells, dendritic cells, macrophages, and their associated cytokines is examined, highlighting the importance of targeting cytokine signaling pathways to modulate immune-epithelial interactions. We propose that advances in computation tools will uncover the significance of G-protein coupled receptors (GPCRs) in connecting immune and epithelial cells, leading to novel therapies for EoE and IBD.

Eosinophilic esophagitis (EoE) is a chronic T helper type 2 (Th2)-associated inflammatory disorder triggered by food allergens, resulting in esophageal dysfunction through edema, fibrosis, and tissue remodeling. The role of epithelial remodeling in EoE pathogenesis is critical but not fully understood.

To investigate the role of epithelial IKKβ/NFκB signaling in EoE pathogenesis using a mouse model with conditional Ikk β knockout in esophageal epithelial cells ( Ikk β EEC-KO ).

EoE was induced in Ikkβ EEC-KO mice through skin sensitization with MC903/Ovalbumin (OVA) followed by intraesophageal OVA challenge. Histological and transcriptional analyses were performed to assess EoE features. Single-cell RNA sequencing (scRNA-seq) was used to profile esophageal mucosal cell populations and gene expression changes.

Ikkβ EEC-KO /EoE mice exhibited hallmark EoE features, including eosinophil infiltration, intraepithelial eosinophils, microabscesses, basal cell hyperplasia, and lamina propria remodeling. RNA-seq revealed significant alterations in IKKβ/NFκB signaling pathways, with decreased expression of RELA and increased expression of IKKβ negative regulators. scRNA- seq analyses identified disrupted epithelial differentiation and barrier integrity, alongside increased type 2 immune responses and peptidase activity.

Our study demonstrates that loss of epithelial IKKβ signaling exacerbates EoE pathogenesis, highlighting the critical role of this pathway in maintaining epithelial homeostasis and preventing allergic inflammation. The Ikkβ EEC-KO /EoE mouse model closely mirrors human EoE, providing a valuable tool for investigating disease mechanisms and therapeutic targets. This model can facilitate the development of strategies to prevent chronic inflammation and tissue remodeling in EoE.

Critical Role of Epithelial IKKβ/NFκB Signaling: Loss of this signaling exacerbates EoE, causing eosinophil infiltration, basal cell hyperplasia, and tissue remodeling, highlighting its importance in esophageal health.Molecular Insights and Therapeutic Targets: scRNA-seq identified disrupted epithelial differentiation, barrier integrity, and enhanced type 2 immune responses, suggesting potential therapeutic targets for EoE. Relevance of the Ikkβ EEC-KO /EoE Mouse Model: This model replicates human EoE features, making it a valuable tool for studying EoE mechanisms and testing treatments, which can drive the development of effective therapies.

This study reveals the crucial role of epithelial IKKβ/NFκB signaling in EoE, providing insights into disease mechanisms and potential therapeutic targets, highly relevant for advancing clinical management of EoE.

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.

Eosinophilic esophagitis (EoE) and inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC), are immune-mediated gastrointestinal diseases with overlapped pathogenesis and are sometimes concurrently diagnosed, but their causal relationship remains unclear. We investigated the causal relationship between EoE and IBD and its subtypes via a two-sample bidirectional Mendelian randomization (MR) approach.

MR analyses were performed using summary data of a genome-wide association study (GWAS) on individuals of European ancestry. Independent single-nucleotide polymorphisms correlated with EoE (from a GWAS meta-analysis containing 1,930 cases and 13,634 controls) and IBD (from FinnGen GWASs containing 9,083 IBD, 2,033 CD, and 5,931 UC cases, and GWASs of IBD genetic consortium containing 12,882 IBD, 6,968 UC, and 5,956 CD cases) were selected as instruments. We applied the inverse variance weighted (IVW) method as the primary analysis followed by several sensitivity analyses. For the forward MR study, estimates from IVW methods were subsequently meta-analyzed using a random-effect model.

Our results suggested a causal effect of EoE on IBD [pooled odds ratio (OR), 1.07; 95% confidence interval (CI), 1.02-1.13] and EoE on UC (pooled OR, 1.09, 95% CI, 1.04-1.14). No causal link between EoE and CD was observed (pooled OR, 1.05; 95% CI, 0.96-1.16). The reverse MR analyses revealed no causal effect of IBD (and its subtypes) on EoE. Sensitivity analyses confirmed the robustness of primary results.

Our findings provided evidence of a suggestive causal effect of EoE on IBD (specifically on UC) in the European population. Increased awareness of concurrent or subsequent IBD in patients with EoE is called for. Still, the present evidence is not adequate enough and ought to be validated by further investigations.

Coordinated cell interactions within the esophagus maintain homeostasis, and disruption can lead to eosinophilic esophagitis (EoE), a chronic inflammatory disease with poorly understood pathogenesis. We profile 421,312 individual cells from the esophageal mucosa of 7 healthy and 15 EoE participants, revealing 60 cell subsets and functional alterations in cell states, compositions, and interactions that highlight previously unclear features of EoE. Active disease displays enrichment of ALOX15+ macrophages, PRDM16+ dendritic cells expressing the EoE risk gene ATP10A, and cycling mast cells, with concomitant reduction of TH17 cells. Ligand-receptor expression uncovers eosinophil recruitment programs, increased fibroblast interactions in disease, and IL-9+IL-4+IL-13+ TH2 and endothelial cells as potential mast cell interactors. Resolution of inflammation-associated signatures includes mast and CD4+ TRM cell contraction and cell type-specific downregulation of eosinophil chemoattractant, growth, and survival factors. These cellular alterations in EoE and remission advance our understanding of eosinophilic inflammation and opportunities for therapeutic intervention.

Eosinophilic esophagitis is a male-predominant disease with presentations ranging from nonspecific feeding issues to dysphagia and food impaction. The currently proposed pathophysiology is a combination of genetics, allergens, and epithelial barrier impairment. Diagnosis is reliant on history, endoscopic examination, and biopsy. Recent guidelines recognize the role of concurrent gastroesophageal reflux disease. Treatment is based on 3 paradigms: diet, drugs, and dilation. Drug therapy has historically focused on topical corticosteroids; as of 2022, dupilumab was approved for targeted biologic therapy. Dilation is reserved for symptomatic and anatomic management. As this clinical entity is better understood, additional therapies will hopefully be developed.

Eosinophilic esophagitis (EoE) is characterized by persistent or relapsing allergic inflammation, and both clinical and histologic features of esophageal inflammation persist over time in most individuals. Mechanisms contributing to EoE relapse are not understood, and chronic EoE-directed therapy is therefore required to prevent long-term sequelae.

We investigated whether EoE patients in histologic remission have persistent dysregulation of esophageal gene expression.

Esophageal biopsy samples from 51 pediatric and 52 adult subjects with EoE in histopathologic remission (<15 eosinophils per high-power field [eos/hpf]) and control (48 pediatric and 167 adult) subjects from multiple institutions were subjected to molecular profiling by the EoE diagnostic panel, which comprises a set of 94 esophageal transcripts differentially expressed in active EoE.

Defining remission as <15 eos/hpf, we identified 51 and 32 differentially expressed genes in pediatric and adult EoE patients compared to control individuals, respectively (false discovery rate < 0.05). Using the stringent definition of remission (0 eos/hpf), the adult and pediatric cohorts continued to have 18 and 25 differentially expressed genes (false discovery rate < 0.05). Among 6 shared genes between adults and children, CDH26 was upregulated in both children and adults; immunohistochemistry demonstrated increased cadherin 26 staining in the epithelium of EoE patients in remission compared to non-EoE controls. In the adult cohort, POSTN expression correlated with the endoscopic reference system score (Spearman r = 0.35, P = .011), specifically correlating with the rings' endoscopic reference system subscore (r = 0.53, P = .004).

We have identified persistent EoE-associated esophageal gene expression in patients with disease in deep remission. These data suggest potential inflammation-induced epigenetic mechanisms may influence gene expression during remission in EoE and provide insight into possible mechanisms that underlie relapse in EoE.

Exposure of the esophageal mucosa to food allergens can cause acute mucosal responses in patients with eosinophilic esophagitis (EoE), but the underlying local immune mechanisms driving these acute responses are not well understood.

We sought to gain insight into the early transcriptomic changes that occur during an acute mucosal response to food allergens in EoE.

Bulk RNA sequencing was performed on esophageal biopsy specimens from adult patients with EoE (n = 5) collected before and 20 minutes after intramucosal injection of various food extracts in the esophagus. Baseline biopsy specimens from control subjects without EoE (n = 5) were also included.

At baseline, the transcriptome of the patients with EoE showed increased expression of genes related to an EoE signature. After local food injection, we identified 40 genes with a potential role in the early immune response to food allergens (most notably CEBPB, IL1B, TNFSF18, PHLDA2, and SLC15A3). These 40 genes were enriched in processes related to immune activation, such as the acute-phase response, cellular responses to external stimuli, and cell population proliferation. TNFSF18 (also called GITRL), a member of the TNF superfamily that is best studied for its costimulatory effect on T cells, was the most dysregulated early EoE gene, showing a 12-fold increase compared with baseline and an 18-fold increase compared with a negative visual response. Further experiments showed that the esophageal epithelium may be an important source of TNFSF18 in EoE, which was rapidly induced by costimulating esophageal epithelial cells with the EoE-relevant cytokines IL-13 and TNF-α.

Our data provide unprecedented insight into the transcriptomic changes that mediate the acute mucosal immune response to food allergens in EoE and suggest that TNFSF18 may be an important effector molecule in this response.

Eosinophilic esophagitis (EoE) is a chronic immune mediated inflammatory disorder of the esophagus. It is still unknown why children and adults present differently, and there is little evidence about why it is more common in men than women.

Our aim was to synthesize published and unpublished esophageal bulk RNA-sequencing (RNA-seq) data to gain novel insights into the pathobiology of EoE and examine the differences in EoE transcriptome by sex and age group.

Esophageal bulk RNA-seq data from 5 published and 2 unpublished studies resulting in 137 subjects (EoE: N = 76; controls: N = 61) were analyzed. For overall analysis, combined RNA-seq data of patients with EoE were compared with those of controls and subgroup analysis was conducted in patients with EoE by age of the patient (children [<18 years] vs adults [≥18 years]) and sex (female vs male). Gene-set enrichment analysis, ingenuity pathway analysis (IPA), cell-type analysis, immunohistochemistry, and T-cell or B-cell receptor analysis were performed.

Overall analysis identified dysregulation of new genes in EoE compared with controls. IPA revealed that EoE is characterized by a mixed inflammatory response compared with controls. Cell-type analysis showed that cell composition varied with age: children had more mast cells, whereas adults had more macrophages. Finally, gene-set enrichment analysis and IPA revealed pathways that were differentially regulated in adults versus children and male versus female patients with EoE.

Using a unique approach to analyze bulk RNA-seq data, we found that EoE is characterized by a mixed inflammatory response, and the EoE transcriptome may be influenced by age and sex. These findings enhance insights into the molecular mechanisms of EoE.

Heterogeneity characterises inflammatory diseases and different phenotypes and endotypes have been identified. Both innate and adaptive immunity contribute to the immunopathological mechanism of these diseases and barrier damage plays a prominent role triggering type 2 inflammation through the alarmins system, such as anti-Thymic Stromal Lymphopoietin (TSLP). Treatment with anti-TSLP monoclonal antibodies showed efficacy in severe asthma and clinical trials for other eosinophilic diseases are ongoing. The aim of this perspective review is to analyse current advances and future applications of TSLP inhibition to control barrier damage.

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 up-regulated in the esophageal epithelium in EoE. However, the functional roles of LOX in the esophageal epithelium remains unknown.

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.

Single-cell RNA sequencing analysis on patient-derived organoids revealed that LOX was induced by IL13 in differentiated cells. LOX-overexpressing organoids showed suppressed basal and up-regulated differentiation markers. In addition, LOX overexpression enhanced junctional protein genes and transepithelial electrical resistance. LOX overexpression restored the impaired differentiation and barrier function, including in the setting of IL13 stimulation. Transcriptome analyses on LOX-overexpressing organoids identified an enriched bone morphogenetic protein (BMP) signaling pathway compared with wild-type organoids. In particular, LOX overexpression increased BMP2 and decreased the BMP antagonist follistatin. Finally, we found that BMP2 treatment restored the balance of basal and differentiated cells.

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

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.

Eosinophilic esophagitis (EoE) is a rare atopic disorder associated with esophageal dysfunction, including difficulty swallowing, food impaction, and inflammation, that develops in a small subset of people with food allergies. Genome-wide association studies (GWASs) have identified 9 independent EoE risk loci reaching genome-wide significance (p < 5 × 10-8) and 27 additional loci of suggestive significance (5 × 10-8 < p < 1 × 10-5). In the current study, we perform linkage disequilibrium (LD) expansion of these loci to nominate a set of 531 variants that are potentially causal. To systematically interrogate the gene regulatory activity of these variants, we designed a massively parallel reporter assay (MPRA) containing the alleles of each variant within their genomic sequence context cloned into a GFP reporter library. Analysis of reporter gene expression in TE-7, HaCaT, and Jurkat cells revealed cell-type-specific gene regulation. We identify 32 allelic enhancer variants, representing 6 genome-wide significant EoE loci and 7 suggestive EoE loci, that regulate reporter gene expression in a genotype-dependent manner in at least one cellular context. By annotating these variants with expression quantitative trait loci (eQTL) and chromatin looping data in related tissues and cell types, we identify putative target genes affected by genetic variation in individuals with EoE. Transcription factor enrichment analyses reveal possible roles for cell-type-specific regulators, including GATA3. Our approach reduces the large set of EoE-associated variants to a set of 32 with allelic regulatory activity, providing functional insights into the effects of genetic variation in this disease.

The incidence of eosinophilic esophagitis (EoE) has been increasing recently. The role of regulatory T cells (Tregs) and correlations with other inflammatory cells in EoE remain unknown. We aim to clarify the role of Tregs and their correlations with inflammatory cells in EoE patients.

Biopsies from controls and EoE patients before and after treatments were analyzed. Eosinophil infiltration was evaluated by hematoxylin and eosin staining. Immunohistochemical staining was performed to examine infiltration of T cells, Tregs, and mast cells. Gene expressions of chemokines were evaluated by reverse transcription-quantitative polymerase chain reaction.

Tregs and mast cells were increased in the esophageal epithelial layers of EoE patients. After treatments, Tregs and mast cells were decreased when histologic remission was achieved. Infiltration of Tregs correlated significantly with numbers of eosinophils and mast cells. Filaggrin mRNA was decreased in patients with EoE before treatment and upregulated after treatment, even when histologic remission was not achieved.

Tregs were increased in esophageal epithelium of patients with EoE, and correlated with mast cell infiltration.

The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture. However, the timing and routes of cereal expansion in key regions are unclear due to limited empirical evidence. Here we report macrofossil, microfossil, multiple isotopic (C/N/Sr/O) and paleoproteomic data directly from radiocarbon-dated human samples, which were unearthed from a site in Xingyi in central Yunnan and which date between 7000 and 3300 a BP. Dietary isotopes reveal the earliest arrival of millet ca. 4900 a BP, and greater reliance on plant and animal agriculture was indicated between 3800 and 3300 a BP. The dietary differences between hunter-gatherer and agricultural groups are also evident in the metabolic and immune system proteins analysed from their skeletal remains. The results of paleoproteomic analysis indicate that humans had divergent biological adaptations, with and without farming. The combined application of isotopes, archaeobotanical data and proteomics provides a new approach to documenting dietary and health changes across major subsistence transitions.

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.

MicroRNA (miRNA)-mediated mRNA regulation directs many homeostatic and pathological processes, but how miRNAs coordinate aberrant esophageal inflammation during eosinophilic esophagitis (EoE) is poorly understood. Here, we report a deregulatory axis where microRNA-155 (miR-155) regulates epithelial barrier dysfunction by selectively constraining tight junction CLDN7 (claudin-7). MiR-155 is elevated in the esophageal epithelium of biopsies from patients with active EoE and in cell culture models. MiR-155 localization using in situ hybridization (ISH) in patient biopsies and intra-epithelial compartmentalization of miR-155 show expression predominantly within the basal epithelia. Epithelial miR-155 activity was evident through diminished target gene expression in 3D organotypic cultures, particularly in relatively undifferentiated basal cell states. Mechanistically, generation of a novel cell line with enhanced epithelial miR-155 stable overexpression induced a functionally deficient epithelial barrier in 3D air-liquid interface epithelial cultures measured by transepithelial electrical resistance (TEER). Histological assessment of 3D esophageal organoid cultures overexpressing miR-155 showed notable dilated intra-epithelial spaces. Unbiased RNA-sequencing analysis and immunofluorescence determined a defect in epithelial barrier tight junctions and revealed a selective reduction in the expression of critical esophageal tight junction molecule, claudin-7. Together, our data reveal a previously unappreciated role for miR-155 in mediating epithelial barrier dysfunction in esophageal inflammation.

Compelling evidence over the past decade supports the central role of epithelial barrier dysfunction in the pathophysiology of eosinophilic esophagitis (EoE). The purpose of this review is to summarize the genetic, environmental, and immunologic factors driving epithelial barrier dysfunction, and how this impaired barrier can further promote the inflammatory response in EoE.

Common environmental exposures, such as detergents, may have a direct impact on the esophageal epithelial barrier. In addition, the effects of IL-13 on barrier dysfunction may be reduced by 17β-estradiol, Vitamin D, and the short chain fatty acids butyrate and propionate, suggesting novel therapeutic targets. There are many genetic, environmental, and immunologic factors that contribute to epithelial barrier dysfunction in EoE. This leads to further skewing of the immune response to a "Th2" phenotype, alterations in the esophageal microbiome, and penetration of relevant antigens into the esophageal mucosa, which are central to the pathophysiology of EoE.

Eosinophilic gastrointestinal diseases (EGIDs) are an emerging group of pathological entities characterized by an eosinophil-predominant infiltration of different tracts of the gut in the absence of secondary causes of eosinophilia. According to the specific tract of the gut involved, EGIDs can be classified into eosinophilic esophagitis (EoE), eosinophilic gastritis (EoG), eosinophilic enteritis (EoN), and eosinophilic colitis (EoC). The epidemiology of EGIDs is evolving rapidly. EoE, once considered a rare disease, now has an incidence and prevalence of 7.7 new cases per 100,000 inhabitants per years and 34.4 cases per 100,000 inhabitants per year, respectively. Fewer data are available regarding non-EoE EGIDs, whose prevalence are estimated to range between 2.1 and 17.6 in 100,000 individuals, depending on age, sex, and ethnicity. Diagnosis requires the presence of suggestive symptoms, endoscopic biopsies showing abnormal values of eosinophils infiltrating the gut, and exclusion of secondary causes of eosinophilia. EoE typically presents with dysphagia and episodes of food bolus impactions, while EoG, EoN, and EoC may all present with abdominal pain and diarrhea, with or without other non-specific symptoms. In addition, although different EGIDs are currently classified as different entities, there may be overlap between different diseases in the same patient. Despite EGIDs being relatively novel pathological entities, the research on possible treatments is rapidly growing. In this regard, several randomized controlled trials are currently ongoing to investigate novel molecules, including ad-hoc steroid formulations, immunosuppressants, and mostly monoclonal antibodies that target the specific molecular mediators of EGIDs. This narrative review provides an up-to-date overview of available and investigational drugs for different EGIDs.