JAK-STAT6 Pathway Inhibitors Block Eotaxin-3 Secretion by Epithelial Cells and Fibroblasts from Esophageal Eosinophilia Patients: Promising Agents to Improve Inflammation and Prevent Fibrosis in 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.

Pharmacologic Management of Eosinophilic Esophagitis

Proton pump inhibitors (PPIs), swallowed topical corticosteroids (STSs), and dupilumab are highly effective therapies for the treatment of eosinophilic esophagitis. Shared decision-making informs the choice of therapy and factors such as ease of use, safety, cost, and efficacy should be addressed. PPIs are the most common medication utilized early in the disease course; however, for nonresponders, STSs are an excellent alternative. Dupilumab is unlikely to replace PPIs or STSs as first-line therapy, except in highly specific circumstances. Identification of novel biologic pathways and the development of small molecules may lead to a wider range of treatment options in the future.

Th2 cytokine signaling through IL-4Rα increases eotaxin-3 secretion and tension in human esophageal smooth muscle

In esophageal epithelial cells in eosinophilic esophagitis (EoE), Th2 cytokines (IL-4, IL-13) signal through IL-4Rα, activating JAK to increase eotaxin-3 secretion, which draws eosinophils into the mucosa. We explored whether Th2 cytokines also might stimulate eotaxin-3 secretion and increase tension in esophageal smooth muscle (ESM), which might impair esophageal distensibility, and whether those events could be blocked by proton pump inhibitors (PPIs) or agents that disrupt IL-4Rα signaling. We established human ESM cell cultures from organ donors, characterizing Th2 cytokine receptor and P-type ATPase expression by qPCR. We measured Th2 cytokine-stimulated eotaxin-3 secretion by enzyme-linked immunosorbent assay (ELISA) and ESM cell tension by gel contraction assay, before and after treatment with omeprazole, ruxolitinib (JAK inhibitor), or IL-4Rα blocking antibody. CPI-17 (inhibitor of a muscle-relaxing enzyme) effects were studied with CPI-17 knockdown by siRNA or CPI-17 phospho(T38A)-mutant overexpression. ESM cells expressed IL-4Rα and IL-13Rα1 but only minimal H+-K+-ATPase mRNA. Th2 cytokines increased ESM eotaxin-3 secretion and tension, effects blocked by ruxolitinib and IL-4Rα blocking antibody but not consistently blocked by omeprazole. IL-13 increased ESM tension by increasing CPI-17 expression and phosphorylation, effects blocked by CPI-17 knockdown. Blocking IL-4Rα decreased IL-13-stimulated eotaxin-3 secretion, CPI-17 expression, and tension in ESM. Th2 cytokines increase ESM eotaxin-3 secretion and tension via IL-4Rα signaling that activates CPI-17. Omeprazole does not reliably inhibit this process, but IL-4Rα blocking antibody does. This suggests that ESM eosinophilia and impaired esophageal distensibility might persist despite elimination of mucosal eosinophils by PPIs, and IL-4Rα blocking agents might be especially useful in this circumstance.NEW & NOTEWORTHY We have found that Th2 cytokines increase eotaxin-3 secretion and tension in esophageal smooth muscle (ESM) cells via IL-4Rα signaling. Unlike esophageal epithelial cells, ESM cells do not express H+-K+-ATPase, and omeprazole does not inhibit their cytokine-stimulated eotaxin-3 secretion or tension. An IL-4Rα blocking antibody reduces both eotaxin-3 secretion and tension induced by Th2 cytokines in ESM cells, suggesting that an agent such as dupilumab might be preferred for patients with EoE with esophageal muscle involvement.

Assessment of the Severity and the Remission Criteria in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an immune-mediated disease that manifests with dysphagia and is characterized by the predominantly eosinophilic infiltration of the esophageal mucosa. Several instruments have been developed to assess the symptoms of EoE: the Daily Symptom Questionnaire (DSQ), EoE Activity Index (EEsAI), Pediatric EoE Symptom Severity (PEESSv2), etc. The use of the EREFS is a gold standard for endoscopic diagnosis. The EoE histologic scoring system (EoEHSS) was elaborated for the assessment of histological features in EoE. However, the remission criteria are not clearly defined and vary greatly in different studies. Gastroenterologists establish the severity of EoE mainly based on endoscopic findings. At the same time, EoE requires a multidisciplinary approach. The recently developed Index of Severity of Eosinophilic Esophagitis (I-SEE) that is built on symptoms, endoscopic findings, and histological features is promising.

Mechanistic Insights into Eosinophilic Esophagitis: Therapies Targeting Pathophysiological Mechanisms

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease characterized by eosinophilic infiltration of the esophagus. It arises from a complex interplay of genetic predisposition (susceptibility loci), environmental triggers (allergens and dietary antigens), and a dysregulated immune response, mainly mediated by type 2 T helper cell (Th2)-released cytokines, such as interleukin (IL)-4, IL-5, and IL-13. These cytokines control eosinophil recruitment and activation as well as tissue remodeling, contributing to the characteristic features of EoE. The pathogenesis of EoE includes epithelial barrier dysfunction, mast cell activation, eosinophil degranulation, and fibrosis. Epithelial barrier dysfunction allows allergen penetration and promotes immune cell infiltration, thereby perpetuating the inflammatory response. Mast cells release proinflammatory mediators and promote eosinophil recruitment and the release of cytotoxic proteins and cytokines, causing tissue damage and remodeling. Prolonged inflammation can lead to fibrosis, resulting in long-term complications such as strictures and dysmotility. Current treatment options for EoE are limited and mainly focus on dietary changes, proton-pump inhibitors, and topical corticosteroids. Novel therapies targeting key inflammatory pathways, such as monoclonal antibodies against IL-4, IL-5, and IL-13, are emerging in clinical trials. A deeper understanding of the complex pathogenetic mechanisms behind EoE will contribute to the development of more effective and personalized therapeutic strategies.

Proteomic aptamer analysis reveals serum biomarkers associated with disease mechanisms and phenotypes of systemic sclerosis

Background

Systemic sclerosis (SSc) is an autoimmune connective tissue disease that affects multiple organs, leading to elevated morbidity and mortality with limited treatment options. The early detection of organ involvement is challenging as there is currently no serum marker available to predict the progression of SSc. The aptamer technology proteomic analysis holds the potential to correlate SSc manifestations with serum proteins up to femtomolar concentrations.

Methods

This is a two-tier study of serum samples from women with SSc (including patients with interstitial lung disease - ILD - at high-resolution CT scan) and age-matched healthy controls (HC) that were first analyzed with aptamer-based proteomic analysis for over 1300 proteins. Proposed associated proteins were validated by ELISA first in an independent cohort of patients with SSc and HC, and selected proteins subject to further validation in two additional cohorts.

Results

The preliminary aptamer-based proteomic analysis identified 33 proteins with significantly different concentrations in SSc compared to HC sera and 9 associated with SSc-ILD, including proteins involved in extracellular matrix formation and cell-cell adhesion, angiogenesis, leukocyte recruitment, activation, and signaling. Further validations in independent cohorts ultimately confirmed the association of specific proteins with early SSc onset, specific organ involvement, and serum autoantibodies.

Conclusions

Our multi-tier proteomic analysis identified serum proteins discriminating patients with SSc and HC or associated with different SSc subsets, disease duration, and manifestations, including ILD, skin involvement, esophageal disease, and autoantibodies.

Research trends in the field of the gut-brain interaction: Functional dyspepsia in the spotlight – An integrated bibliometric and science mapping approach

Objectives

This study aims to perform a bibliometric analysis of functional dyspepsia (FD), which includes visualizing bibliographic information, in order to identify prevailing study themes, topics of interest, contributing journals, countries, institutions, and authors as well as co-citation patterns.

Methods

The Web of Science™ Core Collection Database was used to retrieve all peer-reviewed scientific publications related to FD research. The validated search terms were entered into the “title” and “author keywords” fields, and the results were sorted by publication year from 2006 to 2022. There were no restrictions on language. On 12 February 2023, a manual export of the complete metadata for each original publication and review article was performed. CiteSpace was used to reveal co-authorship, publication, and co-citation patterns to find prominent authors, organizations, countries, and journals in FD research as well as to identify author keywords with strong citation bursts, which could indicate an emerging research area. VOSviewer was used to build the co-occurrence indicator (co-word) to identify the main author keywords on which previous studies focused and to induce clustered scientific landscape for two consecutive periods to identify intriguing areas for future research.

Results

A search of the database retrieved 2,957 documents. There was a wave-like pattern in the number of publications until 2017, after which there was a spike in publication volume. The USA, China, and Japan provided the majority of contributions. In terms of institution, Mayo Clin, Univ Newcastle, and Katholieke Univ Leuven were found to be the prolific institutions. Additionally, the results indicate that eastern Asian researchers contributed significantly to the global knowledge of literature that led other countries; however, Canada, the USA, Australia, England, and Germany were found to have the highest degree of betweenness centrality. Nicholas J. Talley, Jan Tack, Gerald Holtmann, Michael Camilleri, Ken Haruma, and Paul Moayyedi occupied the top positions based on productivity and centrality indicators. Six thematic clusters emerged (Helicobacter pylori infection; pathophysiological mechanisms of FD; extraintestinal co-morbidities and overlap syndromes associated with FD; herbal medicine in FD; diabetic gastroparesis; and dietary factors in FD). “Acupuncture,” “duodenal eosinophilia,” “gut microbiota,” and others were among the author keywords with rising prevalence.

Conclusion

In FD research, eastern Asian countries have established themselves as major contributors with the highest publishing productivity; however, research has primarily been driven by North America, Europe, and Australia, where cooperation is generally more active and highly influential scientific results are produced. Our analysis suggests that increased investments, training of human resources, improved infrastructures, and expanded collaborations are essential to improving the quality of FD research in Asia. The emerging author keyword analysis suggests that eosinophil-mast cell axis, gut microbiota, mental disorders, and acupuncture are the key areas that attract researchers’ attention as future research boulevards. There is a highly skewed distribution of research output across Asia, with most focus on complementary and alternative medicine (CAM) coming from Chinese, Japanese, and South Korean centers. However, CAM remains an underexplored area of research in the context of FD, and it deserves greater research efforts in order to obtain quality scientific evidence. Furthermore, we propose that the research framework of CAM should not be limited to dysmotility; rather, it could be interpreted within a more holistic context that includes the brain-gut-microbiota axis, as well as novel concepts such as duodenitis, increased mucosal permeability, and infiltration and activation of eosinophils and mast cells, among others. Overall, we provided bibliometrics-based overviews of relevant literature to researchers from different backgrounds and healthcare professionals to provide an in-depth overview of major trends in FD research.

Multicentric reticulohistiocytosis with eosinophilic gastroenteritis: An unusual relationship

Multicentric reticulohistiocytosis (MRH) is a rare disease with poorly defined therapeutic strategies. Here, we report the case of a patient with eosinophilic gastroenteritis who developed MRH after 5 years. The patient presented with disabling and rapidly progressive polyarthralgia, eosinophilic gastroenteritis, and resistance to first-line therapies. However, there was a marked improvement in the arthritis symptoms following treatment with tofacitinib. This presentation provides a useful perspective for the therapeutic management of complex scenarios involving MRH.

Proton Pump Inhibitor Therapy in Pediatric Eosinophilic Esophagitis: Predictive Factors and Long-Term Step-Down Efficacy

OBJECTIVES

To assess the short- and long-term efficacy of proton pump inhibitor (PPI) therapy for pediatric eosinophilic esophagitis (EoE) in real-world practice with a step-down strategy, and to evaluate factors predictive of PPI responsiveness.

METHODS

We collected data regarding the efficacy of PPIs during this cross-sectional analysis of the prospective nationwide RENESE registry. Children with EoE treated with PPI monotherapy were included. Histological remission was defined as a peak eosinophilic count of <15 eosinophils (eos)/high-power field (hpf). Factors associated with PPI responsiveness were identified using multivariate logistic regression analysis.

RESULTS

After induction therapy, histological and clinico-histological remission were observed in 51.4% (n = 346) and 46.5% of children, respectively. Normal endoscopic appearance of the esophagus was associated with a higher possibility [odds ratio (OR), 9.20; 95% confidence interval (CI), 2.10-40.16], and fibrostenotic phenotype was associated with a lower possibility (OR, 0.36; 95% CI, 0.18-0.74) of histological remission. Long-term therapy with a step-down strategy effectively maintained histological remission in 68.5% and 85.3% of children at 7 months (n = 108) and 16 months (n = 34), respectively. Complete initial histological remission (≤5 eos/hpf) was associated with a higher possibility of sustained histological remission (OR, 5.08; 95% CI, 1.75-14.68). Adverse events were infrequent and mild.

CONCLUSIONS

We confirmed the efficacy of PPIs for a large cohort of children with EoE with sustained histological remission using a step-down strategy. Children with fibrostenotic phenotypes are less likely to respond to induction therapy. Furthermore, patients with complete initial histological remission are more likely to experience long-term histological remission.

STAT6 suppression prevents bleomycin-induced dermal fibrosis

Fibrosis of the skin and internal organs is a hallmark of systemic sclerosis (SSc). Although the pathogenesis of SSc is poorly understood, increasing evidence suggests that interleukins (IL)-4 and - 13 contribute to the pathogenesis of skin fibrosis by promoting collagen production and myofibroblast differentiation. Signal transducers and activators of transcription 6 (STAT6) is one of the most important downstream transcription factors activated by both IL-4 and IL-13. However, it is not completely understood whether STAT6 plays a role during the pathogenesis of skin fibrosis in SSc. In this study, we observed increased STAT6 phosphorylation in fibrotic skin samples collected from SSc patients as well as bleomycin-injected murine mice. Knockout of Stat6 in mice significantly (1) suppressed the expression of fibrotic cytokines including Il13, Il17, Il22, Ccl2, and the alternatively activated macrophage marker Cd206; (2) reduced the production of collagen and fibronectin, and (3) attenuated late-stage skin fibrosis and inflammation induced by bleomycin. Consistently, mice treated with STAT6 inhibitor AS1517499 also attenuated skin fibrosis on day 28. In addition, a co-culture experiment demonstrated that skin epithelial cells with STAT6 knockdown had reduced cytokine expression in response to IL-4/IL-13, and subsequently attenuated fibrotic protein expression in skin fibroblasts. On the other side, STAT6 depletion in skin fibroblasts attenuated IL-4/IL-13-induced cytokine and fibrotic marker expression, and reduced CXCL2 expression in co-cultured keratinocytes. In summary, our study highlighted an important yet not fully understood role of STAT6 in skin fibrosis by driving innate inflammation and differentiation of alternatively activated macrophages in response to injury.

Immune Activation in Functional Dyspepsia: Bystander Becoming the Suspect

Disorders of gut-brain interaction (DGBI), formerly termed functional gastrointestinal disorders (FGID), are highly prevalent although exact pathophysiological mechanisms remain unclear. Intestinal immune activation has been recognized, but increasing evidence supports a pivotal role for an active inflammatory state in these disorders. In functional dyspepsia (FD), marked eosinophil and mast cell infiltration has been repeatedly demonstrated and associations with symptoms emphasize the relevance of an eosinophil-mast cell axis in FD pathophysiology. In this Review, we highlight the importance of immune activation in DGBI with a focus on FD. We summarize eosinophil biology in both homeostasis and inflammatory processes. The evidence for immune activation in FD is outlined with attention to alterations on both cellular and molecular level, and how these may contribute to FD symptomatology. As DGBI are complex and multifactorial conditions, we shed light on factors associated to, and potentially influencing immune activation, including bidirectional gut-brain interaction, allergy and the microbiota. Crucial studies reveal a therapeutic benefit of treatments targeting immune activation, suggesting that specific anti-inflammatory therapies could offer renewed hope for at least a subset of DGBI patients. Lastly, we explore the future directions for DGBI research that could advance the field. Taken together, emerging evidence supports the recognition of FD as an immune-mediated organic-based disorder, challenging the paradigm of a strictly functional nature.

Making Research Flourish Through ESPGHAN: A Position Paper From the ESPGHAN Special Interest Group for Basic and Translational Research

ABSTRACT

Recent research breakthroughs have emerged from applied basic research throughout all scientific areas, including adult and paediatric gastroenterology, hepatology and nutrition (PGHAN). The research landscape within the European Society of Paediatric Gastroenterology and Nutrition (ESPGHAN) is also inevitably changing from clinical research to studies involving applied laboratory research. This position paper aims to depict the current status quo of basic science and translational research within ESPGHAN, and to delineate how the society could invest in research in the present and future time. The paper also explores which research areas in the field of PGHAN represent the current and future priorities, and what type of support is needed across the ESPGHAN working groups (WGs) and special interest groups (SIGs) to fulfil their research goals.

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.

Case Report: Eosinophilic Esophagitis in a Patient With a Novel STAT1 Gain-of-Function Pathogenic Variant

Background

STAT1 gain-of-function (GOF) is a primary immune dysregulatory disorder marked by wide infectious predisposition (most notably chronic mucocutaneous Candidiasis), autoimmunity, vascular disease and malignant predisposition. While atopic features have been described in some STAT1 GOF patients, they are not considered a predominant feature of the disease. Additionally, while eosinophilic gastrointestinal infiltration has been reported in some cases, this has always been described in the context of pre-existing oropharyngeal and/or esophageal Candidiasis.

Clinical cases

Herein, we report 3 members of a multi-generational family diagnosed with STAT1 GOF caused by a novel mutation in the N-terminal domain, c.194A>C (p.D65A). The proband presented initially with a long-standing history of treatment-refractory eosinophilic esophagitis (EoE) without preceding gastrointestinal tract fungal infections, and her mother was diagnosed with esophagitis as well.

Conclusion

EoE has been previously associated with alterations to STAT6 and STAT3 signaling pathways. The current report expands the possible association between JAK/STAT-related disorders and EoE, suggesting that EoE could be a primary disease manifestation of STAT1 GOF, even in the absence of oropharyngeal and/or esophageal Candidiasis.

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation, whose incidence is rising. It significantly affects patients’ quality of life and, if left untreated, results in fibrotic complications. Although broad consensus has been achieved on first-line therapy, a subset of patients remains non-responder to standard therapy. The pathogenesis of EoE is multifactorial and results from the complex, still mostly undefined, interaction between genetics and intrinsic factors, environment, and antigenic stimuli. A deep understanding of the pathophysiology of this disease is pivotal for the development of new therapies. This review provides a comprehensive description of the pathophysiology of EoE, starting from major pathogenic mechanisms (genetics, type 2 inflammation, epithelial barrier dysfunction, gastroesophageal reflux, allergens, infections and microbiota) and subsequently focusing on the single protagonists of type 2 inflammation (involved cells, cytokines, soluble effectors, surface proteins and transcription factors) that could represent present and future therapeutic targets, while summarizing previous therapeutic approaches in literature.

Nitric oxide could promote development of Barrett's esophagus by S-nitrosylation-induced inhibition of Rho-ROCK signaling in esophageal fibroblasts

Barrett's esophagus arises in the process of wound healing in distal esophageal epithelium damaged by gastroesophageal reflux disease. Differentiation of fibroblast into myofibroblasts, a smooth muscle cell-like phenotype and tissue contraction are crucial processes in wound healing. No study has evaluated mechanism by which luminal esophageal nitric oxide (NO) affect Rho-associated coiled coil-forming protein kinase (Rho-ROCK) signaling pathway, a key factor of tissue contraction, in stromal fibroblasts to develop Barrett's esophagus. Using esophageal fibroblasts, we performed collagen-based cell contraction assays and evaluated influence of Rho-ROCK signaling in the exposure to acidic bile salts and NOC-9, which is an NO donor. We found that enhanced cell contraction induced by acidic bile salts was inhibited by NO, accompanied by decrease in phosphorylated myosin light chain expression and stress fiber formation. NO directly S-nitrosylated GTP-RhoA and consequently blocked Rho-ROCK signaling. Moreover, exposure to NO and Y27632, a Rho-ROCK signaling inhibitor, decreased α-SMA expression and increased bone morphogenetic protein-4 (BMP4) expression and secretion. These findings could account for the increased expression of BMP4 in the columnar epithelial cells and stromal fibroblasts in human Barrett's esophagus. NO could impair wound contraction by blocking the Rho-ROCK signaling pathway and promote the development of Barrett's esophagus.NEW & NOTEWORTHY Barrett's esophagus is the condition where esophageal epithelium damaged by gastroesophageal reflux disease (GERD) is abnormally healed via replacing of metaplastic columnar epithelium, but very few studies have conducted focusing wound healing in the development of Barrett's esophagus. Esophageal luminal nitric oxide inhibits Rho-ROCK signaling pathway in esophageal fibroblasts, which leads to delay tissue contraction, a pivotal step in proper wound healing. Moreover, this inhibition increases tissue BMP4 expression. Impaired wound healing could be related to Barrett's esophagus.

Eosinophilic Esophagitis: A Review

Importance

Eosinophilic esophagitis (EoE) is a chronic immune-mediated inflammatory disease of the esophagus that affects an estimated 34.4/100 000 people in Europe and North America. EoE affects both children and adults, and causes dysphagia, food impaction of the esophagus, and esophageal strictures.

Observations

EoE is defined by symptoms of esophageal dysfunction, such as vomiting, dysphagia, or feeding difficulties, in a patient with an esophageal biopsy demonstrating at least 15 eosinophils per high-power field in the absence of other conditions associated with esophageal eosinophilia such as gastroesophageal reflux disease or achalasia. Genetic factors and environmental factors, such as exposure to antibiotics early in life, are associated with EoE. Current therapies include proton pump inhibitors; topical steroid preparations, such as fluticasone and budesonide; dietary therapy with amino acid formula or empirical food elimination; and endoscopic dilation. In a systematic review of observational studies that included 1051 patients with EoE, proton pump inhibitor therapy was associated with a histologic response, defined as less than 15 eosinophils per high-power field on endoscopic biopsy, in 41.7% of patients, while placebo was associated with a 13.3% response rate. In a systematic review of 8 randomized trials of 437 patients with EoE, topical corticosteroid treatment was associated with histologic remission in 64.9% of patients compared with 13.3% for placebo. Patients with esophageal narrowing may require dilation. Objective assessment of therapeutic response typically requires endoscopy with biopsy.

Conclusions and Relevance

EoE has a prevalence of approximately 34.4/100 000 worldwide. Treatments consist of proton pump inhibitors, topical steroids, elemental diet, and empirical food elimination, with esophageal dilation reserved for patients with symptomatic esophageal narrowing.

An Update on Eosinophilic Esophagitis: Etiological Factors, Coexisting Diseases, and Complications

BACKGROUND

Eosinophilic esophagitis (EoE) is an immune-mediated clinicopathological condition characterized by esophageal infiltration with eosinophils resulting in chronic inflammation and stricture.

SUMMARY

The recent increase in the incidence of EoE and the characteristic presentation of symptoms with difficulty swallowing and food bolus impaction has raised key concerns of clinicians as well as researchers. EoE often presents with dysphagia, food impaction, nausea, regurgitation or vomiting, and decreased appetite. It is more common in males, affecting both adults and children. The causative manner of this condition is complex and multifactorial. Throughout recent years, researchers have made a significant contribution to understanding the pathogenesis of EoE, genetic background, natural history, work on allergy, and standardization in the evaluation of disease activity. There is relatively high prevalence of EoE among the population, emphasizing the importance of this disease. Key messages: Esophageal involvement with eosinophils may be manifested as isolated or with coexisting conditions and should be taken into consideration in the differential diagnosis. This study aimed to provide gastroenterologists with novel insights into the evaluation of esophageal involvement with eosinophils and to pay special attention to the etiological factors, coexisting clinical diseases, and complications.

Drugs in Focus: Proton Pump Inhibitors

Proton pump inhibitors (PPIs) are amongst the most commonly prescribed drugs in infants and children with the last decades witnessing a dramatic rise in their utilization. Although PPIs are clearly effective when used appropriately and have been regarded as safe drugs, there is growing evidence regarding their potential adverse effects. Although, largely based on adult data it is clear that many of these are also relevant to pediatrics. PPI use potentially affects gastrointestinal microbiota composition and function, decreases defence against pathogens resulting in increased risk for infections, interferes with absorption of minerals and vitamins leading to specific deficiencies and increased risk for bone fractures as well as interferes with protein digestion resulting in increased risk of sensitization to allergens and development of allergic diseases and eosinophilic esophagitis. An association with gastric, liver and pancreatic cancer has also been inferred from adult data but is tenuous and causation is not proven. Overall, evidence for these adverse events is patchy and not always compelling. Overall, the use of PPIs, for selected indications with a good evidence base, has significant potential benefit but carries more caution in infants and children. Pediatricians should be aware of the concerns regarding the potential adverse events associated with their use.

Targeted Therapies for Eosinophilic Gastrointestinal Disorders

The growing recognition of eosinophilic gastrointestinal disorders has revealed the limitations of current treatment (mainly based on dietary modification and corticosteroids), and include refractoriness, high recurrence rates, and the need for long-term therapy. Research efforts, mainly in eosinophilic esophagitis (EoE), have unveiled essential pathophysiological mechanisms leading to these disorders, which bear some similarities to those of atopic manifestations and are shared by eosinophilic gastroenteritis (EGE) and eosinophilic colitis (EC). Novel targeted therapies, some imported from bronchial asthma and atopic dermatitis, are currently being assessed in EoE. The most promising are monoclonal antibodies, including those targeting interleukin (IL)-13 (cendakimab) and IL-4 (dupilumab), with phase 3 trials currently ongoing. The potential of anti-integrin therapy (vedolizumab) and Siglec-8 blockers (antolimab) in EGE are also promising. Non-biological therapies for eosinophilic gut disorders, which include preventing the activation of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and chemoattractant receptor expressed on T helper 2 cells (CRTH2) signaling pathways, and other potential targets that deserve investigation in eosinophilic gut disorders, are reviewed.

Dominant atopy risk mutations identified by mouse forward genetic analysis

BACKGROUND

Atopy, the overall tendency to become sensitized to an allergen, is heritable but seldom ascribed to mutations within specific genes. Atopic individuals develop abnormally elevated IgE responses to immunization with potential allergens. To gain insight into the genetic causes of atopy, we carried out a forward genetic screen for atopy in mice.

METHODS

We screened mice carrying homozygous and heterozygous N-ethyl-N-nitrosourea (ENU)-induced germline mutations for aberrant antigen-specific IgE and IgG1 production in response to immunization with the model allergen papain. Candidate genes were validated by independent gene mutation.

RESULTS

Of 31 candidate genes selected for investigation, the effects of mutations in 23 genes on papain-specific IgE or IgG1 were verified. Among the 20 verified genes influencing the IgE response, eight were necessary for the response, while 12 repressed IgE. Nine genes were not previously implicated in the IgE response. Fifteen genes encoded proteins contributing to IgE class switch recombination or B-cell receptor signaling. The precise roles of the five remaining genes (Flcn, Map1lc3b, Me2, Prkd2, and Scarb2) remain to be determined. Loss-of-function mutations in nine of the 12 genes limiting the IgE response were dominant or semi-dominant for the IgE phenotype but did not cause immunodeficiency in the heterozygous state. Using damaging allele frequencies for the corresponding human genes and in silico simulations (Monte Carlo) of undiscovered atopy mutations, we estimated the percentage of humans with heterozygous atopy risk mutations.

CONCLUSIONS

Up to 37% of individuals may be heterozygous carriers for at least one dominant atopy risk mutation.

Eosinophilic esophagitis: from pathophysiology to management

Eosinophilic esophagitis (EoE) incidence and prevalence have sharply increased in the last decade; so, the management of these patients is changing rapidly. Standard regimens as elimination diet, proton pump inhibitors and topical swallowed steroids are not able to achieve remission in all patients. Moreover, loss of efficacy and safety concerns for long-term medical treatments are rising questions. As for other chronic immune-mediated diseases, biologics have been evaluated for the treatment of EoE. Several targets in the Th2-mediated inflammatory cascade with eosinophilic mucosal infiltration, have been tested with alternating results. This review provides a comprehensive discussion of the available studies evaluating biologics in EoE and the possible future options most desirable for these patients.

Proton-pump Inhibitor Response Prediction Using Esophageal microRNAs in Children With Eosinophilic Esophagitis

OBJECTIVES

Eosinophilic esophagitis (EoE) is a chronic esophageal disease characterized by eosinophilic inflammation. Proton-pump inhibitors (PPI) induce disease remission but no predictive factors of PPI-responsiveness have been identified yet. So, a biomarker must be found to differentiate between responders (PPI-R) and nonresponder patients (PPI-NR) to PPI. Aims were to identify any molecular biomarker that could predict PPI responsiveness and to study molecular remission after PPI therapy.

METHODS

This prospective study enrolled 39 controls and 43 pediatric children with EoE from 2 hospitals, and they were treated with esomeprazole for 8 to 12 weeks. After therapy, patients were classified as either PPI-R or PPI-NR. Biopsies were collected and RNA, microRNAs, and proteins were isolated from them, measuring levels by qPCR and Western blot (WB). Also, miRNAs were evaluated in serum.

RESULTS

We found several esophageal miRNAs with different expression values between PPI-R and PPI-NR children, which can be used to discriminate them (area under curve = 0.90). No useful serum miRNAs were, however, identified. Also, these miRNAs were dysregulated in responder patients before and after PPI therapy. Moreover, we corroborated in this child population, that PPI-R displayed a significant decrease in eotaxin-3, IL-5, IL-13, periostin, and major basic protein (P < 0.05) and a significant increase in filaggrin levels after PPI treatment (P < 0.01).

CONCLUSIONS

Esophageal miRNA levels found are able to discriminate between both PPI-R and PPI-NR at baseline, and before and after treatment in PPI-R, so they could be used as biomarkers. Furthermore, we observed clinical and esophageal molecular restoration in PPI-R patients after PPI therapy.

Efficacy of proton pump inhibitor therapy for eosinophilic oesophagitis in 630 patients: results from the EoE connect registry

BACKGROUND

Proton pump inhibitors (PPIs) are the most commonly used first-line therapy for patients with eosinophilic oesophagitis (EoE). However, many aspects related to PPIs in EoE are still unknown.

AIMS

To assess the effectiveness of PPI therapy for EoE in real-world practice.

METHODS

This cross-sectional study collected data on PPI efficacy from the multicentre EoE CONNECT database. Clinical remission was defined as a decrease of ≥50% in dysphagia symptom score; histological remission was defined as a peak eosinophil count below 15 eosinophils per high-power field. Factors associated with effectiveness of PPI therapy were identified by binary logistic regression multivariate analyses.

RESULTS

Overall, 630 patients (76 children) received PPI as initial therapy (n = 600) or after failure to respond to other therapies (n = 30). PPI therapy achieved eosinophil density below 15 eosinophils per high-power field in 48.8% and a decreased symptom score in 71.0% of patients. More EoE patients with an inflammatory rather than stricturing phenotype accomplished clinico-histological remission after PPI therapy (OR 3.7; 95% CI, 1.4-9.5); as well as those who prolonged treatment length from 8 to 12 weeks (OR 2.7; 95% CI, 1.3-5.3). After achieving clinico-histological remission of EoE, PPI dosage reduction was effectively maintained in 69.9% of patients, but tended to be less effective among those with a stricturing phenotype.

CONCLUSIONS

Inflammatory EoE phenotype and treatment duration up to 12 weeks correlated with greater chance for inducing remission of EoE. A stricturing phenotype decreased response rates to PPI therapy both initially and in the long term.

STAT signaling in polycystic kidney disease

The most common form of polycystic kidney disease (PKD) in humans is caused by mutations in the PKD1 gene coding for polycystin1 (PC1). Among the many identified or proposed functions of PC1 is its ability to regulate the activity of transcription factors of the STAT family. Most STAT proteins that have been investigated were found to be aberrantly activated in kidneys in PKD, and some have been shown to be drivers of disease progression. In this review, we focus on the role of signal transducer and activator of transcription (STAT) signaling pathways in various renal cell types in healthy kidneys as compared to polycystic kidneys, on the mechanisms of STAT regulation by PC1 and other factors, and on the possibility to target STAT signaling for PKD therapy.

Proton Pump Inhibitors in Children: the Good, the Bad, and the Ugly

PURPOSE OF REVIEW

The evidence supporting or contesting the prescription of proton pump inhibitors (PPIs) for children and updates on side effects are reviewed.

RECENT FINDINGS

PPIs remain an important therapeutic option for esophagitis and gastritis. However, recent studies demonstrate no benefit when prescribing PPIs for chronic cough, infantile reflux, asthma, or functional gastrointestinal disorders. Recent studies suggest adverse effects on microbiome diversity and immune function, resulting in increased rates of gastrointestinal infections, bone fractures, and atopic disorders. PPIs influence a variety of cell types within the in the innate and adaptive immune systems. PPI prescriptions in children may be indicated for select conditions; however, multiple side effects and immune effects have been described. While most of these side effects are rare and mild, some studies suggest enduring adverse effects. Future studies to elucidate the mechanism behind some of these immune and infectious complications will be beneficial.

Effects of tristetraprolin on doxorubicin (adriamycin)-induced experimental kidney injury through inhibiting IL-13/STAT6 signal pathway

To study the effects of Tristetraprolin (TTP) on Doxorubicin (DOX)-induced experimental kidney injury (KI). DOX was used to induce kidney injury in Balb/c male mice (in vivo) and in human kidney proximal tubular epithelial cell line (HK-2) and normal rat kidney epithelial cell line (NRK-52E) (in vitro). Body weight of experimental mice were recorded daily. Histological changes were observed using hematoxylin-eosin (HE) staining, and levels of blood urea nitrogen, serum creatinine and serum cystatin C in KI mice, and MDA, LDH and SOD in cells were detected using the corresponding kits. Meanwhile, the 2, 7-dichlorodihydrofluorescein diacetate (DCF-DA) fluorescent staining was used to assess intracellular levels of reactive oxygen species (ROS). TTP and Kim-1 expressions were measured by immunohistochemistry and western blot. The TNF-α, IL-1β and IL-6 levels were evaluated by ELISA. Expressions of IL-13, STAT6, p-STAT6, Bcl-2, Bax, cleaved-caspase3 were detected using western blot, respectively. Cell Counting Kit-8 (CCK-8) was conducted for analyzing cell viability, and cells apoptosis were assessed by DAPI staining and flow cytometry. DOX treatment decreased body weight and aggravated renal injury without changes in water and food intake. DOX significantly reduced TTP expression, stimulated IL-13/STAT6 pathway and elevated the levels of several factors related to renal injury, including inflammatory response, oxidative stress and cell apoptosis, which were significantly restored by the treatment of overexpression TTP in vitro. Overexpression of TTP significantly reduces DOX-induced adverse outcomes so as to prevent renal injury. Inhibition of IL-13/STAT6 pathway may be the functional mechanism under TTP in experimental KI.

Eosinophilic esophagitis in esophageal atresia: Tertiary care experience of a "selective" approach for biopsy sampling

BACKGROUND

A high prevalence (9.5-30%) of eosinophilic esophagitis (EoE) in patients with esophageal atresia (EA) has been reported. The application of the EoE criteria to EA patients might be problematic. To date, only studies using a "routine" biopsy approach, even in asymptomatic patients, have been performed. The aim of the study was to establish the prevalence of EoE among symptomatic EA patients (EA/EoE group) without anastomotic stricture (AS) and to compare their characteristics with those of EoE patients from general population (EoE group).

METHODS

From 2005 to 2018, we reviewed charts of children with EA and EoE. "Selective" biopsy approach only in EA children without AS and/or endoscopic feature of EoE was performed. Characteristics of EA/EoE and EoE groups were compared.

RESULTS

Among 370 EA and 118 EoE, 15 EA/EoE patients were detected (4.0% of EA patients). Male predominance and a high prevalence of allergy without differences between EA/EoE and EoE groups was observed. EA/EoE children were significantly younger (p < 0.0001). PPI-responder patients were significantly more prevalent in EA/EoE group (p = 0.045).

CONCLUSION

Our data confirm that EA patients are at high risk for developing EoE. High incidence, early onset, and high prevalence of PPI-responders might suggest that esophageal motility disorders interact to increase propensity to EoE in EA patients. However, our study also suggests that overdiagnosis of EoE may occur in EA and that adapted criteria for EoE diagnosis should be developed for EA patients.

TRIAL REGISTRATION

Not applicable for this retrospective study.

Treatment-resistant eosinophilic oesophagitis successfully managed with tofacitinib

We present a case of a 34-year-old man with long-term diagnosis of eosinophilic oesophagitis (EoE) who did not achieve control of disease after multiple therapies including topical and systemic steroids, immune modulators and biologics. Initial endoscopic findings showed signs of active eosinophilic oesophagitis and biopsies were significant for up to 100 eosinophils per high power field during his various treatments. There was a significant improvement in the appearance of the oesophagus as well as the least number of eosinophils found in oesophagus biopsies after 3 months of treatment with tofacitinib. There are no cases of EoE treated with tofacitinib. Tofacitinib should be considered for the treatment of eosinophilic oesophagitis given its evolving role as an immunosuppressive agent.

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.

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.

17β-Estradiol protects the esophageal epithelium from IL-13-induced barrier dysfunction and remodeling

BACKGROUND

The incidence of eosinophilic esophagitis (EoE) is greater in male than female subjects, and the underlying molecular basis for this sex bias remains unclear.

OBJECTIVE

We sought to delineate the contribution of the sex hormone estrogen to the EoE phenotype and esophageal epithelial barrier function and remodeling.

METHODS

We performed demographic and incidence analyses of EoE in male and female subjects from a single-center pediatric cohort. Estrogen-responsive gene expression analyses and estrogen receptor (ESR) immunofluorescence staining of esophageal biopsy specimens from patients with EoE and control subjects were performed. The effect of 17β-estradiol (E2) on IL-13-induced signaling pathways, gene expression, and esophageal epithelial architecture and barrier function in a primary human esophageal keratinocyte cell (EPC2) culture system (EPC2-air-liquid interface) was examined.

RESULTS

We observed a male predominance in patients with EoE. Analyses of RNA sequencing data sets revealed a significant dysregulation of the estrogen-responsive gene network and expression of ESR1 and ESR2 in esophageal biopsy specimens from patients with EoE compared with control subjects. IL-13 stimulation of EPC2-air-liquid interface cells led to altered cellular architecture with induced dilation of intercellular spaces and barrier dysfunction. Pretreatment of EPC2s with E2 prior to IL-13 exposure abrogated IL-13-induced architectural changes and esophageal barrier dysfunction. Mechanistically, E2-protective effects were dependent on ESR2 and associated with diminishing of IL-13-induced tyrosine kinase 2 and signal transducer and activator of transcription 6 phosphorylation and EoE-dysregulated gene expression.

CONCLUSIONS

Estrogen-responsive genes are modified in patients with EoE compared with control subjects. E2 attenuated IL-13-induced architectural changes and esophageal epithelial barrier dysfunction through inhibition of the IL-13/tyrosine kinase 2/signal transducer and activator of transcription 6 pathway via ESR2-dependent process. Estrogen hormone signaling may protect against development of EoE in female subjects.

Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic disorder characterized by symptoms of esophageal dysfunction and esophageal inflammation with intraepithelial eosinophils. EoE represents an important cause of upper gastrointestinal morbidity. Primary care providers are pivotal for timely and accurate recognition of symptoms of eosinophilic esophagitis, for facilitating diagnoses through specialist referrals, and for understanding management strategies. This process begins with a thorough understanding of the clinical features of EoE, its associated atopic conditions, and its evolving epidemiology.

Eosinophilic esophagitis: novel concepts regarding pathogenesis and clinical manifestations

This report explores two hypotheses regarding eosinophilic esophagitis (EoE): (1) that the use of proton pump inhibitors (PPIs) might contribute to the pathogenesis of EoE by preventing peptic digestion of food allergens, by increasing gastric mucosal permeability to enable gastric absorption of those undegraded food allergens, and by causing microbial dysbiosis, and (2) that EoE, like eosinophilic gastroenteritis, might have mucosal-predominant and muscle-predominant forms, and that the muscle-predominant form of EoE might cause a variety of esophageal motility disorders including achalasia.

Acidic Bile Salts Induce Epithelial to Mesenchymal Transition via VEGF Signaling in Non-Neoplastic Barrett's Cells

BACKGROUND & AIMS

Metaplastic glands buried under squamous epithelium are frequently detected in patients with Barrett esophagus (BE). This subsquamous intestinal metaplasia might be responsible for cancers that develop despite endoscopic surveillance and for metaplasia recurrences after endoscopic ablation. To determine whether reflux induces BE cells to undergo an epithelial-to-mesenchymal transition (EMT) that produces subsquamous intestinal metaplasia, we assessed EMT in BE cells exposed to acidic bile salts and in rat and human esophageal tissues.

METHODS

We compared markers of EMT and cell motility in trans-well and 3-dimensional organotypic culture systems among dysplastic BE epithelial cell lines, nondysplastic telomerase-immortalized BE cell lines (BAR-T), and BAR-T cells exposed acutely or for 20 weeks to acidic bile salts. Vascular endothelial growth factor (VEGF) A was inhibited with a neutralizing antibody or CRISPR-Cas9n and VEGF receptor 2 was inhibited with SU1498 or shRNA, and cells were analyzed by immunohistochemistry, quantitative polymerase chain reaction, or immunoblotting for markers of VEGF signaling and EMT; cell motility was assessed by trans-well assay. We used immunohistochemistry and quantitative polymerase chain reaction to assess EMT markers in the columnar-lined esophagus of rats with surgically induced reflux esophagitis and in esophagectomy specimens from patients with BE.

RESULTS

We detected features of EMT (decreased cadherin 1 [CDH1]; increased fibronectin 1, vimentin, and matrix metalloproteinase 2; and increased motility) in dysplastic BE epithelial cell lines and in BAR-T cells exposed for 20 weeks, but not in unexposed BAR-T cells. Acute acidic bile salt exposure induced expression of zinc finger E-box binding homeobox 1 and 2 (ZEB1/2) in BAR-T cells, which decreased their expression of CDH1 and increased motility; inhibitors of VEGF signaling blocked these effects. Columnar-lined esophagus of rats with reflux esophagitis had increased expression of ZEB1/2 and decreased expression of CDH1 compared with controls. Dysplastic BE tissues also had significantly increased levels of ZEB1 and significantly decreased levels of CDH1 compared with nondysplastic BE tissues.

CONCLUSIONS

In BE cell lines, acidic bile salts induce EMT by VEGF signaling, which increases expression of ZEB1/2, repressors of CDH1. These observations suggest that reflux induces EMT in metaplastic BE tissues, which promotes development of subsquamous intestinal metaplasia.

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.

Pediatric eosinophilic esophagitis: updates for the primary care setting

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a multifactorial, non-IgE-mediated inflammatory disorder of the esophagus and is the most common cause of food impaction in the pediatric population. The purpose of this review is to describe the current recommendations for diagnosis and management of EoE.

RECENT FINDINGS

New data has associated EoE with other allergic disorders of the atopic march as well as several risk factors, which predispose to allergic conditions. A subset of patients with esophageal eosinophilia respond to proton pump inhibitor (PPI) therapy with a partial or complete resolution of esophageal eosinophilia. Therefore, some patients can be treated with PPI alone. If this is unsuccessful, dietary elimination and swallowed steroid therapy are recommended for long-term management. There is a growing appreciation that untreated esophageal inflammation can lead to complications of fibrosis and stricture formation.

SUMMARY

The current review will focus on the diagnosis and management of EoE in the pediatric population. Identification and diagnosis of pediatric patients with EoE is critical to prevent long-term esophageal complications.

Can Eosinophilic Esophagitis Cause Achalasia and Other Esophageal Motility Disorders?

Eosinophilic esophagitis (EoE), a disorder identified by its esophageal mucosal features, often is associated with esophageal motility abnormalities, which are manifestations of esophageal muscle dysfunction. Those motility abnormalities sometimes normalize with treatments that reduce esophageal eosinophilia, suggesting that eosinophils can cause reversible esophageal motility disturbances, perhaps by releasing myoactive and neuroactive eosinophil products. Although achalasia uncommonly is associated with EoE as currently defined, most achalasia patients have evidence of an abnormal accumulation of eosinophils and/or their degranulation products in the esophageal muscularis propria, a location inaccessible to routine endoscopic evaluation. Achalasia is an idiopathic condition resulting from destruction of neurons in the myenteric plexus of the esophagus, and degranulating eosinophils release toxic proteins capable of destroying those neurons, thereby causing the irreversible motility abnormalities of achalasia. This report reviews data on the association of esophageal eosinophilia with achalasia and other esophageal motility abnormalities. Based on this review, we propose that EoE, like eosinophilic gastroenteritis, might have mucosal-predominant and muscle-predominant forms with different clinical manifestations. A muscle-predominant form of EoE could underlie a variety of reversible and irreversible esophageal motility disorders, including achalasia. The concept that esophageal motility abnormalities might develop from a muscle-predominant form of EoE warrants serious consideration and further investigation.

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.

Pathophysiology of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus associated with an atopic predisposition which appears to be increasing in prevalence over the last few decades. Symptoms stem from fibrosis, swelling, and smooth muscle dysfunction. In the past two decades, the etiology of EoE has been and is continuing to be revealed. This review provides an overview of the effects of genetics, environment, and immune function including discussions that touch on microbiome, the role of diet, food allergy, and aeroallergy. The review further concentrates on the pathophysiology of the disease with particular focus on the important concepts of the molecular etiology of EoE including barrier dysfunction and allergic hypersensitivity.

Suppressive Effect of Quercetin on Nitric Oxide Production from Nasal Epithelial Cells In Vitro

Nitric oxide (NO) is known to play pivotal roles as one of the final effector molecules in the development of allergic diseases, including allergic rhinitis (AR). Although quercetin has been reported to attenuate the clinical conditions of AR, its influence on NO production is not well defined. The present study aimed to examine the influence of quercetin on in vitro NO production from nasal epithelial cells after interleukin- (IL-) 4 stimulation. Human nasal epithelial cells (HNEpCs) at a concentration of 1 x 10⁵ cells/ml were stimulated with 10.0 ng/ml of IL-4 in the presence and absence of quercetin. After 48 hours, the culture supernatants were collected and assayed for NO (NO₂ and NO₃) using the Griess method. The influences of quercetin on the transcription factor, STAT6, activation, and iNOS mRNA expression were also examined using ELISA and real-time quantitative RT-PCR, respectively. Addition of quercetin to cell cultures caused suppression of NO production from HNEpCs after IL-4 stimulation. The minimum concentration of quercetin that caused significant suppression was 1.0 nM. Treatment of cells with quercetin at more than 1.0 nM suppressed STAT6 activation and iNOS mRNA expression induced by IL-4 stimulation. The present results strongly suggested that quercetin favorably modified the clinical condition of AR through the suppression of NO production from nasal epithelial cells after IL-4 stimulation.

Biological therapies for eosinophilic gastrointestinal diseases

The scientific basis and the clinical application of mAb therapies that target specific immunologic pathways for eosinophilic gastrointestinal diseases are areas of active interest. There is a growing recognition of a subset of patients with eosinophilic esophagitis whose disease does not respond well to topical steroids or elimination diets. In addition, long-term use of corticosteroids presents possible risks that are currently being evaluated. Systemic therapy with a biologic agent offers potential advantages as a global approach that could limit the need for multiple, locally active medical therapies and allergen avoidance. The identification of novel biologic strategies is ongoing, and the recent validation of instruments and outcome measures to assess disease activity has proved essential in demonstrating efficacy. Studies using biologics that target IL-13 pathways in the treatment of eosinophilic esophagitis have demonstrated substantial promise.

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.

Eosinophilic Esophagitis: Pathophysiology and Definition

Eosinophilic esophagitis is an adaptive immune response to patient-specific antigens, mostly foods. Eosinophilic esophagitis is not solely IgE-mediated and is likely characterized by Th2 lymphocytes with an impaired esophageal barrier function. The key cytokines and chemokines are thymic stromal lymphopoeitin, interleukin-13, CCL26/eotaxin-3, and transforming growth factor-β, all involved in eosinophil recruitment and remodeling. Chronic food dysphagia and food impactions, the feared late complications, are related in part to dense subepithelial fibrosis, likely induced by interleukin-13 and transforming growth factor-β.

The Role of Proton Pump Inhibitors in the Management of Pediatric Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic, local, immune-mediated disorder characterized by symptoms of esophageal dysfunction and the presence of a dense eosinophilic infiltrate in the esophageal mucosa. Consensus diagnostic recommendations for EoE diagnosis included absence of histological response to a proton-pump inhibitor (PPI) trial, to exclude gastro-oesophageal reflux disease (GERD)-associated esophagitis. This recommendation exposed an entity known as "proton pump inhibitor-responsive esophageal eosinophilia" (PPI-REE), which refers to patients with EoE phenotype who are PPI-responsive and do not present GERD. In recent years, there is evidence which indicates that PPI-REE is a sub-phenotype of EoE with similar clinical, endoscopic, histological and genetic characteristics, as well as Th2-related inflammatory response. As a result, PPIs should be considered another treatment for EoE and not a diagnostic tool. PPI-REE was originally described in a case series which included two children and in two retrospective pediatric series. Later, a prospective pediatric study showed a high rate of response to PPIs at high doses with long-term maintenance at lower doses. PPI monotherapy in children with esophageal eosinophilia (EE) has been observed to reduce eotaxin-3 expression in epithelial cells and to practically reverse the allergy and inflammatory transcriptome. These data reveal that PPIs are also an effective treatment for EoE in pediatric patients, although more studies are necessary in order to define the best induction and maintenance treatment regimen, the long-term safety profile and their influence on the occurrence of fibrosis and esophageal remodeling.