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

Understanding tissue injury and remodelling in eosinophilic oesophagitis: development towards personalised medicine

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.

Eosinophil specialization is regulated by exposure to the esophageal epithelial microenvironment

Distinct subsets of eosinophils are reported in inflammatory and healthy tissues, yet the functions of uniquely specialized eosinophils and the signals that elicit them, particularly in eosinophilic esophagitis, are not well understood. Herein, we report an ex vivo system wherein freshly isolated human eosinophils were cocultured with esophageal epithelial cells and disease-relevant proinflammatory (IL-13) or profibrotic (TGF-β) cytokines. Compared with untreated cocultures, IL-13 increased expression of CD69 on eosinophils, whereas TGF-β increased expression of CD81, CD62L, and CD25. Eosinophils from IL-13-treated cocultures demonstrated increased secretion of GRO-α, IL-8, and macrophage colony-stimulating factor and also generated increased extracellular peroxidase activity following activation. Eosinophils from TGF-β-treated cocultures secreted increased IL-6 and exhibited increased chemotactic response to CCL11 compared with eosinophils from untreated or IL-13-treated coculture conditions. When eosinophils from TGF-β-treated cocultures were cultured with fibroblasts, they upregulated SERPINE1 expression and fibronectin secretion by fibroblasts compared with eosinophils that were cultured with granulocyte macrophage colony-stimulating factor alone. Translational studies revealed that CD62L was heterogeneously expressed by eosinophils in patient biopsy specimens. Our results demonstrate that disease-relevant proinflammatory and profibrotic signals present in the esophagus of patients with eosinophilic esophagitis cause distinct profiles of eosinophil activation and gene expression.

CSF1-dependent macrophage support matrisome and epithelial stress-induced keratin remodeling in Eosinophilic esophagitis

Atopic diseases such as Eosinophilic Esophagitis (EoE) often progress into fibrosis (FS-EoE), compromising organ function with limited targeted treatment options. Mechanistic understanding of FS-EoE progression is confounded by the lack of preclinical models and the heavy focus of research on eosinophils themselves. We found that macrophage accumulation precedes esophageal fibrosis in FS-EoE patients. We developed a FS-EoE model via chronic administration of oxazalone allergen, in a transgenic mouse over-expressing esophageal epithelial hIL-5 (L2-IL5OXA). These mice display striking histopathologic features congruent with that found in FS-EoE patients. Unbiased proteomic analysis, using a unique extracellular-matrix (ECM) focused technique, identified an inflammation-reactive provisional basal lamina membrane signature and this was validated in two independent EoE patient RNA-sequencing/proteomic cohorts, supporting model significance. A wound healing signature was also observed involving hemostasis-associated molecules previously unnoted in EoE. We further identified the ECM glycoprotein, Tenascin-C (TNC), and the stress-responsive keratin-16 (KRT16) as IL-4 and IL-13 responsive mediators, acting as biomarkers of FS-EoE. To mechanistically address how the immune infiltrate shapes FS-EoE progression, we phenotyped the major immune cell subsets that coalesce with fibrosis in both the L2-IL5OXA mice and in FS-EoE patients. We found that macrophage are required for matrisome and cytoskeletal remodeling. Importantly, we show that macrophage accumulation precedes esophageal fibrosis and provide a novel therapeutic target in FS-EoE as their depletion with anti-CSF1 attenuated reactive matrisome and cytoskeletal changes. Thus, macrophage-based treatments and the exploration of TNC and KRT16 as biomarkers may provide novel therapeutic options for patients with fibrostenosis.

Esophageal remodeling in eosinophilic esophagitis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Differential Contributions of Fibroblast Subpopulations to Intercellular Communication in Eosinophilic Esophagitis

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

Development and dysfunction of structural cells in eosinophilic esophagitis

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

Pathophysiology and Clinical Impact of Esophageal Remodeling and Fibrosis in Eosinophilic Esophagitis

Most of the major clinical signs and consequences of eosinophilic esophagitis seem to be related to tissue remodeling. Important data on remodeling activity in patients with eosinophilic esophagitis are provided by a range of current and new biologic markers and diagnostics. To completely clarify the possible advantages and restrictions of therapeutic approaches, clinical studies should take into consideration the existence and reversibility of esophageal remodeling. The degree of mucosal or submucosal disease activity may not be reflected by epithelial eosinophilic inflammation, which is used to define one criterion of disease activity".

TGF-β1 inhibitor P144 protects against benign restenosis after esophageal stenting through TGF-β1/Smads signaling pathway inhibition

BACKGROUND AND STUDY AIMS

Esophageal restenosis is a serious complication after esophageal stent placement, which influences the clinical prognosis of stent implantation and the patient's quality of life. TGF-β1/Smads signaling pathway plays an important role in the development of the eosinophilic esophagitis and scar repair after skin trauma. However, the role of TGF-β1/Smads in the development of esophageal restenosis after esophageal stent placement remains unknown. Our study aimed to investigate whether TGF-β1/Smads plays an important role in the development of esophageal restenosis after esophageal stent, and whether the exogenous TGF-β1 inhibitor supplement could ameliorate the esophageal restenosis after esophageal stent.

MATERIAL AND METHODS

We established the model of esophageal restenosis after esophageal stenting in rats, and determined the expression levels of TGF-β1/Smads signaling pathway and the relevant markers of fibroblast activation by immunochemistry (IHC), Western Blot and real time qPCR. Those all the indicators were also determined in esophageal fibroblast when exposed to rhTGF-β1 with or without TGF-β1 inhibitor P144.

RESULTS

The serum level of IL-1β and TNFα were significantly increased in stent implantation group compared to blank control group, and obviously ameliorated when treated with P144. The TGF-β1/Smads signaling pathway and the relevant markers of fibroblast activation were significantly increased in stent implantation group compared to blank control group, and obviously ameliorated when treated with P144. Those all the indicators were significantly increased when exposed to rhTGF-β1, and obviously decreased when treated with P144.

CONCLUSIONS

TGF-β1 Inhibitor P144 could protect against benign restenosis after esophageal stenting by down-regulating the expression levels of relevant markers of fibroblast activation through TGF-β1/Smads signaling pathway inhibition, and may be used as a novel therapy for benign restenosis after esophageal stenting.

Lysyl Oxidase Regulates Epithelial Differentiation and Barrier Integrity in Eosinophilic Esophagitis

BACKGROUND & AIMS

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

METHODS

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

RESULTS

Single-cell RNA sequencing analysis on patient-derived organoids revealed that LOX was induced by 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.

CONCLUSIONS

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.

Epithelial-Fibroblast Crosstalk in Eosinophilic Esophagitis

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

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

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

Effect of esophageal muscle fibrosis on prognosis of per-oral endoscopic myotomy (POEM) in achalasia patients

BACKGROUND AND AIMS

Although esophageal smooth muscle fibrosis of achalasia (AC) patients has been described, the role and mechanism remain unclear. The aim of this study was to evaluate the fibrosis in the distal esophageal muscle in patients with AC and explore its relationship with prognosis of per-oral endoscopic myotomy (POEM).

METHODS

Lower esophageal sphincter (LES) muscle from forty patients undergoing POEM for AC were obtained at the time of surgery. Control specimens consisted of similar muscle taken from distal esophagectomy for gastric tumors. The muscle fibrosis were assessed by Masson staining and confirmed by immunohistochemistry for collagen I and III. The total number of eosinophil within the myenteric propria were counted. In addition, clinical data were obtained through electronic medical records. Statistical comparison between groups were made.

RESULTS

A significantly higher proportion of fibrosis in AC as compared with controls (P = 0.000). Eosinophil count, TGF-β1, collagen I, and III were higher than those of control (P = 0.000, P = 0.001, P = 0.011, and P = 0.002, respectively). TGF-β1, collagen I, and III were positively correlated with eosinophil count (all P < 0.05). Furthermore, the proportion of severe LES fibrosis in patients who failed to respond to POEM two years after operation was higher than that in responders (P = 0.028). And, Eckardt score two years after POEM was also positively correlated with degree of fibrosis-related cytokines (all P < 0.05).

CONCLUSION

Smooth muscle fibrosis was prominent in lower part of esophagus of AC and positively correlated with severity of symptoms two years after POEM. The fibrosis might be relevant to eosinophil infiltration and TGF-β1. Further studies are required to more clearly delineate the mechanism of muscle fibrosis and its correlation with prognosis of therapy for this idiopathic disease.

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.

A unique esophageal extracellular matrix proteome alters normal fibroblast function in severe eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic TH2 disorder complicated by tissue fibrosis and loss of esophageal luminal patency. The fibrostenotic esophagus does not respond well to therapy, but profibrotic therapeutic targets are largely unclear.

OBJECTIVE

Our aim was to utilize proteomics and primary cells as a novel approach to determine relevant profibrotic factors.

METHODS

We utilized primary esophageal EoE and normal fibroblasts, their derivative extracellular matrixes (ECMs), an approach of fibroblast culture on autologous versus nonautologous ECM, and proteomics to elucidate EoE ECM proteins that dysregulate cellular function.

RESULTS

We cultured esophageal fibroblasts from normal esophagi and esophagi from patients with severe EoE on autologous versus nonautologous ECM. The EoE ECM proteome shifted normal esophageal fibroblast protein expression. Proteomic analysis demonstrated that thrombospondin-1 is detected only in the EoE ECM, is central in the EoE ECM protein-protein interactome, is found at significantly elevated levels in biopsy specimens from patients with active EoE, and induces fibroblast collagen I production.

CONCLUSION

Fibroblasts from patients with EoE secrete a unique ECM proteome that reflects their in vivo state and induces collagen I and α-smooth muscle actin protein expression from normal fibroblasts. Thrombospondin-1 is a previously unappreciated profibrotic molecule in EoE.

Antifibrotic Effects of the Thiazolidinediones in Eosinophilic Esophagitis Pathologic Remodeling: A Preclinical Evaluation

Eosinophilic esophagitis (EoE) is a T-helper 2 (Th2), eosinophilic disease associated with pathologic tissue remodeling that leads to end-organ dysfunction. During early-stage disease, inflammation and subepithelial fibrosis are coupled and reversible, but in late-stage or therapy-resistant disease, there can be uncoupling of these features with progressive esophageal rigidity and strictures contributing to clinical dysphagia and food impactions. No current pharmacotherapeutic interventions directly target esophageal fibrosis. Based on the ability of the thiazolidinediones (TZD) to regulate intestinal and hepatic fibrosis, we tested the antifibrotic effects of the TZDs, rosiglitazone and pioglitazone, in preclinical studies using primary human esophageal fibroblasts.

Increased Production of LIGHT by T Cells in Eosinophilic Esophagitis Promotes Differentiation of Esophageal Fibroblasts Toward an Inflammatory Phenotype

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) is an antigen-mediated eosinophilic disease of the esophagus that involves fibroblast activation and progression to fibrostenosis. Cytokines produced by T-helper type 2 cells and transforming growth factor beta 1 (TGFβ1) contribute to the development of EoE, but other cytokines involved in pathogenesis are unknown. We investigate the effects of tumor necrosis factor superfamily member 14 (TNFSF14, also called LIGHT) on fibroblasts in EoE.

METHODS

We analyzed publicly available esophageal CD3+ T-cell single-cell sequencing data for expression of LIGHT. Esophageal tissues were obtained from pediatric patients with EoE or control individuals and analyzed by immunostaining. Human primary esophageal fibroblasts were isolated from esophageal biopsy samples of healthy donors or patients with active EoE. Fibroblasts were cultured; incubated with TGFβ1 and/or LIGHT; and analyzed by RNA sequencing, flow cytometry, immunoblots, immunofluorescence, or reverse transcription polymerase chain reaction. Eosinophils were purified from peripheral blood of healthy donors, incubated with interleukin 5, cocultured with fibroblasts, and analyzed by immunohistochemistry.

RESULTS

LIGHT was up-regulated in the esophageal tissues from patients with EoE, compared with control individuals, and expressed by several T-cell populations, including T-helper type 2 cells. TNF receptor superfamily member 14 (TNFRSF14, also called HVEM) and lymphotoxin beta receptor are receptors for LIGHT that were expressed by fibroblasts from healthy donors or patients with active EoE. Stimulation of esophageal fibroblasts with LIGHT induced inflammatory gene transcription, whereas stimulation with TGFβ1 induced transcription of genes associated with a myofibroblast phenotype. Stimulation of fibroblasts with TGFβ1 increased expression of HVEM; subsequent stimulation with LIGHT resulted in their differentiation into cells that express markers of myofibroblasts and inflammatory chemokines and cytokines. Eosinophils tethered to esophageal fibroblasts after LIGHT stimulation via intercellular adhesion molecule-1.

CONCLUSIONS

T cells in esophageal tissues from patients with EoE express increased levels of LIGHT compared with control individuals, which induces differentiation of fibroblasts into cells with inflammatory characteristics. TGFβ1 increases fibroblast expression of HVEM, a receptor for LIGHT. LIGHT mediates interactions between esophageal fibroblasts and eosinophils via ICAM1. This pathway might be targeted for the treatment of EoE.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Enzyme-injected method of enzymatic dispersion at low temperature is effective for isolation of smooth muscle cells from human esophagogastric junction

The present study was conducted to examine the feasibility of in vitro isolation and primary culture of smooth muscle cells (SMCs) from the esophagogastric junction (EGJ). Smooth muscles of EGJ were harvested from 23 patients with esophageal cancer during esophagostomy from January 2015 to December 2017. Enzymatic dispersion (ED) was performed for isolation. Collagenase II and Trypsin/EDTA were applied by enzyme injection (EI) into tissue fragments or immersion of tissue fragments into enzyme solution. Growth characteristics and proliferation [Cell Counting Kit-8 (CCK-8)] of cells were recorded for both smooth muscle cell medium (SMCM) and DMEM/F12 containing 10% newborn bovine serum (10%-F12). All ED methods could isolate primary cells; EI was the most effective method with low collagenase II concentration (0.5 mg/ml) at 4˚C for 14-24 h. Primary cells demonstrated mainly spindle- and long-spindle-shaped with ‘hills and valleys’ morphology. The CCK-8 assay in SMCM showed better proliferation results than in 10%-F12. After passaging for 4-8 generations in SMCM or 2-4 generations in 10%-F12, cells enlarged gradually with passages and lost spindle structures. mRNA and proteins of α-smooth muscle actin (α-SMA), smooth muscle 22 α (SM22α), vimentin, desmin, CD90 and proliferating cell nuclear antigen were detected in tissues and cells with different levels of expression. SMCs of esophageal circular muscle, esophageal longitudinal muscle, gastric circular muscle near sling in gastric bottom and gastric circular muscle near clasp in lesser gastric curvature, all cultured in 10%-F12, exhibited superior smooth muscle phenotypes compared with SMCs cultured in SMCM in terms of α-SMA, SM22α and vimentin expression. The EI method of ED at low temperature appears effective for isolation and primary culture of SMCs from human EGJ in vitro.

TGFβ1 single-nucleotide polymorphism C-509T alters mucosal cell function in pediatric eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic Th2 antigen-driven disorder associated with tissue remodeling. Inflammation and remodeling lead to esophageal rigidity, strictures, and dysphagia. TGFβ1 drives esophageal remodeling including epithelial barrier dysfunction and subepithelial fibrosis. A functional SNP in the TGFβ1 gene that increases its transcription (C-509T) is associated with elevated numbers of esophageal TGFβ1-expressing cells. We utilized esophageal biopsies and fibroblasts from TT-genotype EoE children to understand if TGFβ1 influenced fibroblast and epithelial cell function in vivo. Genotype TT EoE esophageal fibroblasts had higher baseline TGFβ1, collagen1α1, periostin, and MMP2 (p < 0.05) gene expression and distinct contractile properties compared with CC genotype (n = 6 subjects per genotype). In vitro TGFβ1 exposure caused greater induction of target gene expression in genotype CC fibroblasts (p < 0.05). Esophageal biopsies from TT-genotype subjects had significantly less epithelial membrane-bound E-cadherin (p < 0.01) and wider cluster distribution at nanometer resolution. TGFβ1 treatment of stratified primary human esophageal epithelial cells and spheroids disrupted transepithelial resistance (p < 0.001) and E-cadherin localization (p < 0.0001). A TGFβ1-receptor-I inhibitor improved TGFβ1-mediated E-cadherin mislocalization. These data suggest that EoE severity can depend on genotypic differences that increase in vivo exposure to TGFβ1. TGFβ1 inhibition may be a useful therapy in subsets of EoE patients.

EoE disease monitoring: Where we are and where we are going

OBJECTIVE

To review literature on various methods of monitoring and characterizing eosinophilic esophagitis (EoE) with respect to their validity as well as risk to the patient.

DATA SOURCES

A literature search was performed using PubMed with keyword combinations of EoE and monitoring as well as various techniques used for monitoring, including but not limited to, symptoms, endoscopy, histology, fluoroscopy, FLIP, noninvasive monitoring, and biomarkers.

STUDY SELECTIONS

Case-control studies, observational studies, peer-reviewed reviews and guidelines, and systematic reviews were selected, reviewed, and summarized here.

RESULTS

A wealth of research regarding monitoring of EoE is currently being undertaken and published. Our review highlights those that have been validated and are currently being used, as well as some that show promise for future monitoring and disease characterization.

CONCLUSION

Eosinophilic esophagitis is a chronic condition that at this time requires upper endoscopy as the gold standard of diagnosis and monitoring. There is a great need in the field for less invasive monitoring tools and better ways to characterize disease to allow for personalization of therapies.

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.

Development and Application of a Functional Human Esophageal Mucosa Explant Platform to Eosinophilic Esophagitis

There is an increasing prevalence of esophageal diseases but intact human tissue platforms to study esophageal function, disease mechanisms, and the interactions between cell types in situ are lacking. To address this, we utilized full thickness human donor esophagi to create and validate the ex vivo function of mucosa and smooth muscle (n = 25). Explanted tissue was tested for contractile responses to carbachol and histamine. We then treated ex vivo human esophageal mucosa with a cytokine cocktail to closely mimic the Th2 and inflammatory milieu of eosinophilic esophagitis (EoE) and assessed alterations in smooth muscle and extracellular matrix function and stiffening. We found that full thickness human esophagus as well as the individual layers of circular and longitudinal muscularis propria developed tension in response to carbachol ex vivo and that mucosa demonstrated squamous cell differentiation. Treatment of mucosa with Th2 and fibrotic cytokines recapitulated the majority of the clinical Eosinophilic Esophagitis Diagnostic Profile (EDP) on fluidic transcriptional microarray. Transforming growth factor-beta-1 (TGFβ1) increased gene expression of fibronectin, smooth muscle actin, and phospholamban (p < 0.001). The EoE cocktail also increased stiffness and decreased mucosal compliance, akin to the functional alterations in EoE (p = 0.001). This work establishes a new, transcriptionally intact and physiologically functional human platform to model esophageal tissue responses in EoE.

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.

New developments in patients with eosinophilic gastrointestinal diseases presented at the CEGIR/TIGERS Symposium at the 2018 American Academy of Allergy, Asthma & Immunology Meeting

The Consortium of Eosinophilic Gastrointestinal Diseases and the International Gastrointestinal Eosinophil Researchers organized a day-long symposium at the recent 2018 Annual Meeting of the American Academy of Allergy, Asthma & Immunology, which was coupled for the first time with the World Allergy Organization meeting to create an international platform. The symposium featured experts in many facets of eosinophilic gastrointestinal diseases, including allergy, immunology, gastroenterology, pathology, and nutrition, and was a well-attended event. The basic science, genetics, cellular immunology, and clinical features of the diseases, with a focus on epithelial, eosinophil, and mast cell responses, as well as current and emerging treatment options, were reviewed. Here we briefly review some of the highlights of the material presented at the meeting.

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.

Medical and dietary management of eosinophilic esophagitis

OBJECTIVE

Eosinophilic esophagitis (EoE) is a disease of chronic, allergen-driven, T-helper 2 (Th2) immune-mediated inflammation that progresses to fibrostenosis of the esophagus if left untreated. There are currently no Food and Drug Administration (FDA)-approved drugs for the treatment of EoE. This review focuses on the medical and dietary management of EoE.

DATA SOURCES

Manuscripts on EoE treatments were identified on PubMed.

STUDY SELECTIONS

Original research, randomized control trials, retrospective studies, meta-analyses, case series, and on occasions, case reports of high relevance, were selected and reviewed.

RESULTS

Current treatment strategies available to EoE patients center on monotherapy or combination therapy with dietary modification to exclude antigenic stimulation and topical corticosteroids to control Th2-mediated tissue inflammation and pathologic remodeling. Dilation as a rescue therapy for the narrowed, fibrostenotic, symptomatic esophagus can potentially be avoided with optimal medical and elimination diet therapies. The molecular mechanisms underlying EoE pathogenesis are being unraveled, from which targeted therapies can be developed and evaluated in preclinical and clinical studies. Current clinical research efforts focus on optimization of topical corticosteroid delivery, dosing, frequency, and duration of treatment, either alone or in combination with tailored elimination diet. Preliminary clinical trials with biologics targeting interleukin (IL)-5 and IL-13/IL-4 have been completed.

CONCLUSION

Topical corticosteroid, elimination diet, and dilation are the current treatment modalities for confirmed EoE. The use of proton-pump inhibitors (PPI) is being suggested as a potential regimen to treat EoE, based on evolving understanding of PPI-responsive esophageal eosinophilia (PPI-REE). The complexity of EoE treatment regimens and frequent follow-ups require a multimodal, multi-disciplinary management approach to optimize patient care.

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

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

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pathophysiology of Eosinophilic Esophagitis

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

Creating a multi-center rare disease consortium - the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR)

 Eosinophilic gastrointestinal disorders (EGIDs) affect various segments of the gastrointestinal tract. Since these disorders are rare, collaboration is essential to enroll subjects in clinical studies and study the broader population. The Rare Diseases Clinical Research Network (RDCRN), a program of the National Center for Advancing Translational Sciences (NCATS), funded the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR) in 2014 to advance the field of EGIDs. CEGIR facilitates collaboration among various centers, subspecialties, patients, professional organizations and patient-advocacy groups and includes 14 clinical sites. It has successfully initiated two large multi-center clinical studies looking to refine EGID diagnoses and management. Several pilot studies are underway that focus on various aspects of EGIDs including novel therapeutic interventions, diagnostic and monitoring methods, and the role of the microbiome in pathogenesis. CEGIR currently nurtures five physician-scholars through a career training development program and has published more than 40 manuscripts since its inception. This review focuses on CEGIR's operating model and progress and how it facilitates a framework for exchange of ideas and stimulates research and innovation. This consortium provides a model for progress on other potential clinical areas.

Differences in eosinophil molecular profiles between children and adults with eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) afflicts both children and adults. It has been debated whether pediatric EoE and adult EoE represent different disease entities. The objectives of this study were to determine whether the blood eosinophil molecular pattern of children with EoE is (i) distinct from that of healthy children; and (ii) different from that of adults with EoE.

METHODS

Blood eosinophils from children and adults with EoE, and healthy controls, were analyzed with flow cytometry regarding levels of CD23, CD44, CD54, CRTH2, FOXP3, and galectin-10. Eosinophil FOXP3 and galectin-10 mRNA levels were determined by qPCR. The data were analyzed using a multivariate method of pattern recognition.

RESULTS

An eosinophil molecular pattern capable of distinguishing children with EoE from control children was identified. A smaller fraction of eosinophils from children with EoE expressed CD44 and a larger fraction expressed CRTH2 than the controls. Eosinophils from children with EoE also had higher levels of galectin-10 mRNA and lower levels of FOXP3 mRNA. The eosinophils from children with EoE had lower levels of surface CD54 and of FOXP3 mRNA compared with the eosinophils from the adult patients. A key finding was the detection in healthy individuals of age-related differences in the levels of several eosinophil markers.

CONCLUSIONS

Children with EoE can be distinguished from healthy children based on the molecular patterns of their blood eosinophils. Age-related physiologic differences in eosinophil molecular patterns may partly explain the different blood eosinophil phenotypes in children vs adults with EoE.

Tissue Remodeling in Chronic Eosinophilic Esophageal Inflammation: Parallels in Asthma and Therapeutic Perspectives

Chronic eosinophilic inflammation is associated with tissue remodeling and fibrosis in a number of chronic T-helper 2 (Th2)-mediated diseases including eosinophilic esophagitis (EoE) and asthma. Chronic inflammation results in dysregulated tissue healing, leading to fibrosis and end organ dysfunction, manifesting clinically as irreversible airway obstruction in asthma and as esophageal rigidity, strictures, narrowing, dysmotility, dysphagia, and food impactions in EoE. Current therapies for EoE and asthma center on reducing inflammation-driven tissue remodeling and fibrosis with corticosteroids, coupled with symptomatic control and allergen avoidance. Additional control of Th2 inflammation can be achieved in select asthma patients with biologic therapies such as anti-IL-5 and anti-IL-13 antibodies, which have also been trialed in EoE. Recent molecular analysis suggests an emerging role for structural cell dysfunction, either inherited or acquired, in the pathogenesis and progression of EoE and asthma tissue remodeling. In addition, new data suggest that inflammation-independent end organ rigidity can alter structural cell function. Herein, we review emerging data and concepts for the pathogenesis of tissue remodeling and fibrosis primarily in EoE and relevant pathogenetic parallels in asthma, focusing additionally on emerging disease-specific therapies and the ability of these therapies to reduce tissue remodeling in subsets of patients.