Recent discoveries and emerging therapeutics in eosinophilic esophagitis

Gene therapy for a murine model of eosinophilic esophagitis

BACKGROUND

Eosinophils are specialized granulocytic effector cells that store and release highly active mediators used in immune defense. Eosinophils are also implicated in the pathogenesis of allergic disorders, including eosinophilic esophagitis (EoE), a chronic disorder characterized by infiltration of eosinophils into the esophagus and release of mediators that damage tissue, resulting in gastrointestinal morbidity, food impaction, and dysphagia. Treatment with elimination diets and/or topical corticosteroid therapy slow disease progression, but are complicated by adverse effects, limited compliance, and loss of response to therapy. We hypothesized that a single administration of an adeno-associated virus (AAV) coding for an anti-eosinophil monoclonal antibody that induces eosinophil clearance (anti-Siglec-F) would treat on a persistent basis a murine model of EoE.

METHODS

A mouse model of peanut-induced EoE that mimics the human disease was established by sensitization and challenge with peanut extract. After challenge, these mice exhibited an EoE phenotype demonstrated by elevated levels of blood eosinophils, infiltration of eosinophils in the esophagus with associated esophageal remodeling and food impaction.

RESULTS

The mice were treated with a single intravenous administration (10¹¹ genome copies) of AAVrh.10mAnti-Eos, a serotype rh.10 AAV vector coding for an anti-Siglec-F monoclonal antibody. Vector administration resulted in persistent, high levels of anti-Siglec-F antibody expression. Administration of AAVrh.10mAnti-Eos to the mouse model of EoE reduced blood (P < 0.02) and esophageal eosinophil numbers (P < 0.002) protected from esophageal tissue remodeling and minimized food impaction.

CONCLUSION

These results suggest that a single treatment with AAVrh.10mAnti-Eos has the potential to provide persistent therapeutic benefit to patients with EoE.

Successful Management of Eosinophilic Esophagitis Using Traditional Chinese Medicine: A Case Report

Eosinophilic Esophagitis (EoE) is a relatively recently described condition, with rapidly increasing prevalence over the past several years. There is unfortunately no cure for EoE, and treatment involves food elimination and off-label use of topical steroids. These treatments can have significant impacts on quality of life for patients. Traditional Chinese Medicine (TCM) has been shown to decrease Th2 cytokines which are implicated in the pathophysiology of EoE. We present an 11-year-old male with severe EoE who was treated with TCM and able to achieve complete remission. Further modalities of treatment for EoE should continue to be pursued.

Strategy for Food Reintroduction Following Empiric Elimination and Elemental Dietary Therapy in the Treatment of Eosinophilic Gastrointestinal Disorders

PURPOSE OF REVIEW

This review presents the available data regarding efficacy of nutritional therapy, highlighting clinical decision points and a strategy for reintroduction of foods following an elemental diet for treatment of eosinophilic gastrointestinal disorders.

RECENT FINDINGS

Elemental and empiric elimination diets are highly effective treatments for eosinophilic gastrointestinal diseases. Standardization in the reintroduction phase, after utilizing the diet for disease remission, is lacking. Clinicians are confronted with multiple challenges regarding the best practice for food reintroduction and identification of potential dietary triggers including order of foods being challenged and duration between endoscopic procedures. Individualization is required for preference and adherence to optimize quality of life and treatment success for this burdensome and life altering immune driven gastrointestinal disorder. Age specific concerns for children, teenagers, and adults should be assessed using a patient centric approach.

Eosinophilic esophagitis incidence in New Zealand: high but not increasing

Background and aim

Eosinophilic esophagitis (EoE) is an immune-mediated inflammatory condition of the esophagus. Recent literature has shown an increasing incidence of the disease. However, no epidemiological data exist regarding New Zealand rates of EoE. The disease is associated with atopy, and New Zealand's high rate of atopic disease means the disease may be important in our population. We carried out a retrospective study to describe the incidence of EoE in the Wellington region of New Zealand, as well as key histological and clinical factors associated with the disease.

Method

A search was made of laboratory and endoscopic databases in the Wellington region to identify all diagnosed cases in the five years between January 1, 2011, and December 31, 2015. Case notes were examined to determine the key demographic and clinical parameters in the cases. Incidence rates were calculated for each year, and the effects of age group and sex on the incidence rates were analyzed.

Result

We found 152 cases of EoE in the Wellington region with an annual incidence of 6.95 per 100,000 person/years. We found no evidence of a significant difference in incidence rates by year in our study population. There was a significantly lower incidence rate in those aged <16 compared to those aged ≥16 (RR=0.26). Males had a higher incidence rate than females with an estimated rate ratio of 2.45 (p<0.05).

Conclusion

Our results are in contrast to previous reports of increasing incidence rates and may reflect a leveling off of incidence. Further research is needed to determine whether the low incidence in our pediatric age group is due to ascertainment bias or due to a real difference in the epidemiology of EoE in NZ compared to other countries.

Endotypes of Chronic Rhinosinusitis Across Ancestry and Geographic Regions

PURPOSE OF REVIEW

Preliminary studies have suggested differences in endotypes of chronic rhinosinusitis (CRS) across ancestry/ethnic groups. Eosinophilic CRS (ECRS) is the predominant subtype for Western/European ancestry CRS patients and non-eosinophilic CRS (nECRS) for Asian patients. This review aims to re-analyze CRS endotypes across ancestry populations using one consistent criteria to existing data.

RECENT FINDINGS

Although tissue eosinophilia is the most commonly used criterion for ECRS, various cut-off points are suggested. Surrogate markers have been extensively studied. Sixty-six cohorts with study criteria were included with a total of 8557 patients. Raw data from 11 studies 544 patients were re-analyzed using number of tissue eosinophils. At lower cut-off values of ≥ 5 and ≥ 10 cells/HPF, most patients of Asian and Western/European ancestry were classified as ECRS without difference. In contrast, at cut-off points of ≥ 70 and ≥ 120 cells/HPF, the majority of both groups became reclassified as nECRS. After applying one consistent criteria to existing data, differences across ancestry and geographic populations in endotypes of CRS were no longer evident.

Noncanonical NF-κB signaling and the essential kinase NIK modulate crucial features associated with eosinophilic esophagitis pathogenesis

Eosinophilic esophagitis (EoE) is an allergic disease of the esophagus driven by T cell and eosinophil responses to dietary allergens, resulting in chronic mucosal inflammation. Few spontaneous animal models of esophageal eosinophilia exist, with most studies relying on artificial sensitization procedures. NF-κB-inducing kinase (NIK; MAP3K14) is a key signaling molecule of the noncanonical NF-κB (NFKB1) pathway, an alternative signaling cascade producing chemokines involved in lymphoid stroma development and leukocyte trafficking. Nik-/- mice have been shown to develop a hypereosinophilic syndrome in peripheral blood and major filtering organs; however, the gastrointestinal mucosa of these mice has not been well characterized. We show that Nik-/- mice develop significant, localized eosinophilic esophagitis that mimics human EoE, including features such as severe eosinophil accumulation, degranulation, mucosal thickening, fibrosis and basal cell hyperplasia. The remainder of the GI tract, including the caudal stomach, small intestine and colon, in mice with active EoE are unaffected, also similar to human patients. Gene expression patterns in esophageal tissue of Nik-/- mice mimics human EoE, with thymic stromal lymphopoetin (TSLP) in particular also elevated at the protein level. In gene expression data sets from human biopsy specimens, we further show that many genes associated with noncanonical NF-κB signaling are significantly dysregulated in EoE patients, most notably a paradoxical upregulation of NIK itself with concurrent upregulation of powerful protein-level destabilizers of NIK. These findings suggest that Nik-/- mice could be useful as a spontaneous model of specific features of EoE and highlight a novel role for noncanonical NF-κB signaling in human patients.

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.

Pemphigus Vulgaris and Eosinophilic Esophagitis in a 13-Year-Old Boy: Case Report and Review of the Literature

This case report presents a 13-year-old boy referred to the Department of Paediatric Dentistry, Women's and Children's Hospital, Adelaide, South Australia, Australia, with a 5-week history of severe oral ulcerations and significant weight loss of unknown origin. The diagnosis of pemphigus vulgaris was made after histologic and immunofluorescent examination of an intraoral deep incisional biopsy, with eosinophilic esophagitis also diagnosed during the initial upper gastrointestinal endoscopy. The association between pemphigus vulgaris and eosinophilic esophagitis in this case, although previously unreported, is explicable on the basis of dysregulation of desmoglein 1 (DSG1). This case report identifies a new clinical association that could help clinicians identify further such cases and provides insight into the pathogenesis of both conditions.