Research advances in esophageal diseases: bench to bedside

Eosinophilic esophagitis: absolute eosinophilic count, peak eosinophilic count, and potential biomarkers of eosinophilic degranulation products-an in-depth systematic review

Background

Eosinophilic esophagitis is a chronic inflammatory disorder, often relapsing. There is an increasing need to develop new alternative diagnostic and monitoring methods on a critical basis, which will provide samples through none or minimally invasive procedures. This study aims to identify and document the types and roles of potential biomarkers in eosinophilic esophagitis released by eosinophils as well as the potential relationship to the peak eosinophilic count and the degree of degranulation of in situ eosinophils (DGE/DGE + NDGE: degranulated eosinophils/degranulated eosinophils and non-degranulated eosinophils).

Methods

This is the first in-depth systematic review study using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) parameters involving a literature search of academic databases (PubMed, Scopus, Medline, Google Scholar, and Cochrane Database, 2011-2022) targeting specifically the eosinophilic counts and ratio, and the eosinophilic degranulation products as potential biomarkers. Data were extracted from ten selected studies and presented on a spreadsheet.

Results

The studies show the ability to detect eosinophilic and non-eosinophilic degranulation products, and absolute eosinophilic count in samples, including blood and urine, thereby serving as potential surrogates in making the diagnosis or monitoring disease progression in the future. There is an obvious paucity of studies that correlate potential biomarkers to the degree of degranulation of in situ eosinophils.

Conclusions

A few minimally invasive methods and biomarkers may be suggested as alternative tools in diagnosing and monitoring eosinophilic esophagitis. While there is no consensus on the clinical usefulness of these biomarkers, our critical evaluation may suggest that the eosinophilic degranulation ratio (DGE/DGE + NDGE: degranulated eosinophils/degranulated eosinophils and non-degranulated eosinophils) in the esophagus may be critical for evaluating properly these biomarkers. An increasing trend may culminate in the potential clinical use of these biomarkers evaluated not only with the peak eosinophilic count, but also with the degranulation score upon regulatory bodies' approval to monitor eosinophilic esophagitis in the future. We strongly advocate for the necessity to score the esophageal biopsies with both a peak eosinophilic count and a score of the degranulated eosinophils.

Trends in 3D bioprinting for esophageal tissue repair and reconstruction

In esophageal pathologies, such as esophageal atresia, cancers, caustic burns, or post-operative stenosis, esophageal replacement is performed by using parts of the gastrointestinal tract to restore nutritional autonomy. However, this surgical procedure most often does not lead to complete functional recovery and is instead associated with many complications resulting in a decrease in the quality of life and survival rate. Esophageal tissue engineering (ETE) aims at repairing the defective esophagus and is considered as a promising therapeutic alternative. Noteworthy progress has recently been made in the ETE research area but strong challenges remain to replicate the structural and functional integrity of the esophagus with the approaches currently being developed. Within this context, 3D bioprinting is emerging as a new technology to facilitate the patterning of both cellular and acellular bioinks into well-organized 3D functional structures. Here, we present a comprehensive overview of the recent advances in tissue engineering for esophageal reconstruction with a specific focus on 3D bioprinting approaches in ETE. Current biofabrication techniques and bioink features are highlighted, and these are discussed in view of the complexity of the native esophagus that the designed substitute needs to replace. Finally, perspectives on recent strategies for fabricating other tubular organ substitutes via 3D bioprinting are discussed briefly for their potential in ETE applications.

Oesophageal Stem Cells and Cancer

Oesophageal cancer remains one of the least explored malignancies. However, in recent years its increasing incidence and poor prognosis have stimulated interest from the cancer community to understand the pathways to the initiation and progression of the disease.

Critical understanding of the molecular processes controlling changes in stem cell fate and the cross-talk with their adjacent stromal neighbours will provide essential knowledge on the mechanisms that go awry in oesophageal carcinogenesis. Advances in lineage tracing techniques have represented a powerful tool to start understanding changes in oesophageal cell behaviour in response to mutations and mutagens that favour tumour development.

Environmental cues constitute an important factor in the aetiology of oesophageal cancer. The oesophageal epithelium is a tissue exposed to harsh conditions that not only damage the DNA of epithelial cells but also result in an active stromal reaction, promoting tumour progression. Ultimately, cancer represents a complex interplay between malignant cells and their microenvironment. Indeed, increasing evidence suggests that the accumulation of somatic mutations is not the sole cause of cancer. Instead, non-cell autonomous components, coming from the stroma, can significantly contribute from the earliest stages of tumour formation.

The realisation that stromal cells play an important role in cancer has transformed this cellular compartment into an attractive and emerging field of research. It is becoming increasingly clear that the tumour microenvironment provides unique opportunities to identify early diagnostic and prognostic markers, as well as potential therapeutic strategies that may synergise with those targeting tumour cells.

This chapter compiles recent observations on oesophageal epithelial stem cell biology, and how environmental and micro-environmental changes may lead to oesophageal disease and cancer.

Individual patient oesophageal cancer 3D models for tailored treatment

Background

A model to predict chemotherapy response would provide a marked clinical benefit, enabling tailored treatment of oesophageal cancer, where less than half of patients respond to the routinely administered chemotherapy.

Methods

Cancer cells were established from tumour biopsies taken from individual patients about to undergo neoadjuvant chemotherapy. A 3D-tumour growth assay (3D-TGA) was developed, in which cancer cells were grown with or without supporting mesenchymal cells, then subjected to chemo-sensitivity testing using the standard chemotherapy administered in clinic, and a novel emerging HDAC inhibitor, Panobinostat.

RESULTS

Individual patients cancer cells could be expanded and screened within a clinically applicable timescale of 3 weeks. Incorporating mesenchymal support within the 3D-TGA significantly enhanced both the growth and drug resistance profiles of the patients cancer cells. The ex vivo drug response in the presence, but not absence, of mesenchymal cells accurately reflected clinical chemo-sensitivity, as measured by tumour regression grade. Combination with Panobinostat enhanced response and proved efficacious in otherwise chemo-resistant tumours.

Conclusions

This novel method of establishing individual patient oesophageal cancers in the laboratory, from small endoscopic biopsies, enables clinically-relevant chemo-sensitivity testing, and reduces use of animals by providing more refined in vitro models for pre-screening of drugs. The 3D-TGA accurately predicted chemo-sensitivity in patients, and could be developed to guide tailored patient treatment. The incorporation of mesenchymal cells as the stromal cell component of the tumour micro-environment had a significant effect upon enhancing chemotherapy drug resistance in oesophageal cancer, and could prove a useful target for future drug development.

Combination Steroid and Test-based Food Elimination for Eosinophilic Esophagitis: A Retrospective Analysis

OBJECTIVES

Eosinophilic esophagitis (EoE) is a clinicopathologic disorder characterized by infiltration of eosinophils into the esophagus. Primary treatment approaches include topical corticosteroids and/or food elimination. The aim of the present study was to compare the effectiveness of combination therapy (topical corticosteroid plus test-based food elimination [FS]) with single therapy (topical corticosteroid [S] or test-based food elimination [F]).

METHODS

Chart review of patients with EoE at Texas Children's Hospital (age <21 years) was performed. Clinical and histological statuses were evaluated after a 3-month treatment with either single or combination therapy. Comparisons were analyzed using Fisher exact test, Kruskal-Wallis tests, and multiple logistic regression models.

RESULTS

Among 670 charts, 63 patients (1-21 years, median 10.3 years) with clinicopathologic diagnoses of EoE were identified. Combination FS therapy was provided to 51% (n = 32) and single treatment (S, F) to 27% (n = 17) or 22% (n = 14) of patients, respectively. Clinical responses were noted in 91% (n = 29), 71% (n = 12), and 64% (n = 14) of patients in the FS, S, and F groups, respectively. The odds of clinically improving were 4.6 times greater (95% confidence interval: 1.1-18.8) with combination versus single therapy. The median peak number of eosinophils per high-power field after 3-month therapy was not significantly different in the S, F, and FS groups.

CONCLUSIONS

The combination of topical corticosteroids with specific food elimination is as effective in achieving clinical and histological remissions as the single-treatment approaches. Responses were achieved with the combination in patients who had previously failed single-agent therapy. Prospective research of this combination approach in young patients with EoE is needed.

Eosinophilic esophagitis: Update in diagnosis and management. Position paper by the Italian Society of Gastroenterology and Gastrointestinal Endoscopy (SIGE)

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized by symptoms related to esophageal dysfunction, as well as significant esophageal eosinophilia. The entity exists worldwide but has been most extensively studied in Western countries. However, a wide range of symptoms has been noticed such as chest pain or gastro-esophageal reflux disease-like symptoms. Upper gastro-intestinal endoscopy and esophageal biopsies are crucial for the diagnosis. Endoscopy might be normal or reveal typical patterns such as rings, furrows, exudates, edema, and stricture. Two to four biopsies should be performed both in the distal and in the proximal esophagus, and 15 eosinophils per high power field within the esophageal epithelium are the minimal threshold to diagnose eosinophilic esophagitis. Allergy testing is recommended, although its impact to orient treatment remains to be demonstrated. Eosinophilic esophagitis treatment includes medical treatment, diet and endoscopic dilation. Proton pump inhibitors are the first-line therapy as up to 50% of patients respond well to proton pump inhibitors irrespective of objective evidence of GERD. Topical viscous corticosteroids or elimination diet are the treatment of choice in case of unresponsiveness to proton pump inhibitors.

Role of a health psychologist in the management of functional esophageal complaints

Upper gastrointestinal complaints are common among patients in a gastrointestinal clinic. Outside of typical gastroesophageal reflux disease symptoms that are treated with medication, the symptom presentations of esophageal patients, particularly those with functional conditions, are often difficult to treat and account for high health-care utilization. This manuscript describes the role of a health psychologist in the treatment of esophageal disorders using behavioral medicine interventions. Observations over the course of a 1-year period indicate that the sample presents with a relatively low level of psychological distress but reports negative effects of their symptoms on health-related quality of life. Five case examples of commonly treated disorders (globus, non-cardiac chest pain, functional dysphagia, rumination syndrome, supragastric belching) are described to highlight how behavioral treatment can improve patients' symptoms, decrease health-care utilization, and improve overall quality of life in a timely and relatively simple manner. Successful treatment outcomes are associated with a collaborative working alliance between patient, health psychologist, and gastroenterologist. Results indicate the benefit of referring appropriate esophageal patients to a health psychologist with specialization in gastroenterology.

The cancer genome: from structure to function

The 2014 joint meeting of the International Society for Cellular Oncology (ISCO) and the European Workshop on Cytogenetics and Molecular Genetics of Solid Tumors (EWCMST), organized by Nick Gilbert, Juan Cigudosa and Bauke Ylstra, was held from 11 to 14 May in Malaga, Spain. Since the previous meeting in 2012, the ever increasing availability of new sequencing technologies has enabled the analysis of cancer genomes at an increasingly greater detail. In addition to structural changes in the genome (i.e., translocations, deletions, amplifications), frequent mutations in important regulatory genes have been found to occur, as also frequent alterations in a large number of epigenetic factors. The challenge now is to relate structural changes in cancer genomes to the underlying disease mechanisms and to reveal opportunities for the design of novel (targeted) therapies. During the meeting, various topics related to these challenges and opportunities were addressed, including those dealing with functional genomics, genome instability, biomarkers and diagnostics, cancer genetics and epigenomics. Special attention was paid to therapy-driven cancer evolution (keynote lecture) and relationships between DNA repair, cancer and ageing (Prof. Ploem lecture). Based on the information presented at the meeting, several aspects of the cancer genome and its functional implications are provided in this report.

Proton pump inhibitor responsive esophageal eosinophilia, a distinct disease entity?

Recent studies have suggested the existence of a patient population with esophageal eosinophilia that responds to proton pump inhibitor therapy. These patients are being referred to as having proton pump inhibitor responsive esophageal eosinophilia (PPI-REE), which is currently classified as a distinct and separate disease entity from both gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE). The therapeutic effect of proton pump inhibitor (PPI) on PPI-REE is thought to act directly at the level of the esophageal mucosa with an anti-inflammatory capacity, and completely independent of gastric acid suppression. The purpose of this manuscript is to review the mechanistic data of the proposed immune modulation/anti-inflammatory role of the PPI at the esophageal mucosa, and the existence of PPI-REE as a distinct disease entity from GERD and EoE.

Esophageal motility abnormalities in gastroesophageal reflux disease

Esophageal motility abnormalities are among the main factors implicated in the pathogenesis of gastroesophageal reflux disease. The recent introduction in clinical and research practice of novel esophageal testing has markedly improved our understanding of the mechanisms contributing to the development of gastroesophageal reflux disease, allowing a better management of patients with this disorder. In this context, the present article intends to provide an overview of the current literature about esophageal motility dysfunctions in patients with gastroesophageal reflux disease. Esophageal manometry, by recording intraluminal pressure, represents the gold standard to diagnose esophageal motility abnormalities. In particular, using novel techniques, such as high resolution manometry with or without concurrent intraluminal impedance monitoring, transient lower esophageal sphincter (LES) relaxations, hypotensive LES, ineffective esophageal peristalsis and bolus transit abnormalities have been better defined and strongly implicated in gastroesophageal reflux disease development. Overall, recent findings suggest that esophageal motility abnormalities are increasingly prevalent with increasing severity of reflux disease, from non-erosive reflux disease to erosive reflux disease and Barrett’s esophagus. Characterizing esophageal dysmotility among different subgroups of patients with reflux disease may represent a fundamental approach to properly diagnose these patients and, thus, to set up the best therapeutic management. Currently, surgery represents the only reliable way to restore the esophagogastric junction integrity and to reduce transient LES relaxations that are considered to be the predominant mechanism by which gastric contents can enter the esophagus. On that ground, more in depth future studies assessing the pathogenetic role of dysmotility in patients with reflux disease are warranted.