Notch Signaling Mediates Differentiation in Barrett's Esophagus and Promotes Progression to Adenocarcinoma

BACKGROUND & AIMS

Studies are needed to determine the mechanism by which Barrett's esophagus (BE) progresses to esophageal adenocarcinoma (EAC). Notch signaling maintains stem cells in the gastrointestinal tract and is dysregulated during carcinogenesis. We explored the relationship between Notch signaling and goblet cell maturation, a feature of BE, during EAC pathogenesis.

METHODS

We measured goblet cell density and levels of Notch messenger RNAs in BE tissues from 164 patients, with and without dysplasia or EAC, enrolled in a multicenter study. We analyzed the effects of conditional expression of an activated form of NOTCH2 (pL2.Lgr5.N2IC), conditional deletion of NOTCH2 (pL2.Lgr5.N2fl/fl), or loss of nuclear factor κB (NF-κB) (pL2.Lgr5.p65fl/fl), in Lgr5+ (progenitor) cells in L2-IL1B mice (which overexpress interleukin 1 beta in esophagus and squamous forestomach and are used as a model of BE). We collected esophageal and stomach tissues and performed histology, immunohistochemistry, flow cytometry, transcriptome, and real-time polymerase chain reaction analyses. Cardia and forestomach tissues from mice were cultured as organoids and incubated with inhibitors of Notch or NF-kB.

RESULTS

Progression of BE to EAC was associated with a significant reduction in goblet cell density comparing nondysplastic regions of tissues from patients; there was an inverse correlation between goblet cell density and levels of NOTCH3 and JAG2 messenger RNA. In mice, expression of the activated intracellular form of NOTCH2 in Lgr5+ cells reduced goblet-like cell maturation, increased crypt fission, and accelerated the development of tumors in the squamocolumnar junction. Mice with deletion of NOTCH2 from Lgr5+ cells had increased maturation of goblet-like cells, reduced crypt fission, and developed fewer tumors. Esophageal tissues from in pL2.Lgr5.N2IC mice had increased levels of RelA (which encodes the p65 unit of NF-κB) compared to tissues from L2-IL1B mice, and we found evidence of increased NF-κB activity in Lgr5+ cells. Esophageal tissues from pL2.Lgr5.p65fl/fl mice had lower inflammation and metaplasia scores than pL2.Lgr5.N2IC mice. In organoids derived from pL2-IL1B mice, the NF-κB inhibitor JSH-23 reduced cell survival and proliferation.

CONCLUSIONS

Notch signaling contributes to activation of NF-κB and regulates differentiation of gastric cardia progenitor cells in a mouse model of BE. In human esophageal tissues, progression of BE to EAC was associated with reduced goblet cell density and increased levels of Notch expression. Strategies to block this pathway might be developed to prevent EAC in patients with BE.

Reflux Hypersensitivity: How to Approach Diagnosis and Management

PURPOSE OF REVIEW

This paper aims to review the definition and diagnostic criteria for reflux hypersensitivity and comment on the present and future management of this condition.

RECENT FINDINGS

In 2016, the Rome IV criteria redefined reflux hypersensitivity as characterized by typical reflux symptoms, absence of endoscopic mucosal disease, absence of pathologic gastroesophageal reflux, and positive symptom correlation between reflux and heartburn episodes. Though uncertain, TPRV1 receptors have been implicated in the pathophysiology of reflux hypersensitivity. Recent studies have shown neuromodulators like SSRIs, SNRIs, and TCAs may be the future of managing this condition. With the release of the Rome IV criteria and availability of continuous pH monitoring, the diagnosis of reflux hypersensitivity has become more streamlined. Though there is no definitive therapy for reflux hypersensitivity, several anti-secretory agents and neuromodulators have shown some efficacy in therapeutic trials. The lack of large-scale, randomized controlled trials, however, reinforces the need for further research into the pharmacotherapy of reflux hypersensitivity.

Evidence for Cytoprotective Effect of Carbon Monoxide Donor in the Development of Acute Esophagitis Leading to Acute Esophageal Epithelium Lesions

Exposure to acidic gastric content due to malfunction of lower esophageal sphincter leads to acute reflux esophagitis (RE) leading to disruption of esophageal epithelial cells. Carbon monoxide (CO) produced by heme oxygenase (HMOX) activity or released from its donor, tricarbonyldichlororuthenium (II) dimer (CORM-2) was reported to protect gastric mucosa against acid-dependent non-steroidal anti-inflammatory drug-induced damage. Thus, we aimed to investigate if CO affects RE-induced esophageal epithelium lesions development. RE induced in Wistar rats by the ligation of a junction between pylorus and forestomach were pretreated i.g. with vehicle CORM-2; RuCl₃; zinc protoporphyrin IX, or hemin. CORM-2 was combined with NG-nitro-L-arginine (L-NNA), indomethacin, capsazepine, or capsaicin-induced sensory nerve ablation. Esophageal lesion score (ELS), esophageal blood flow (EBF), and mucus production were determined by planimetry, laser flowmetry, histology. Esophageal Nrf-2, HMOXs, COXs, NOSs, TNF-α and its receptor, IL-1 family and IL-1 receptor antagonist (RA), NF-κB, HIF-1α, annexin-A1, suppressor of cytokine signaling (SOCS3), TRPV1, c-Jun, c-Fos mRNA/protein expressions, PGE₂, 8-hydroxy-deoxyguanozine (8-OHdG) and serum COHb, TGF-β1, TGF-β2, IL-1β, and IL-6 content were assessed by PCR, immunoblotting, immunohistochemistry, gas chromatography, ELISA or Luminex platform. Hemin or CORM-2 alone or combined with L-NNA or indomethacin decreased ELS. Capsazepine or capsaicin-induced denervation reversed CORM-2 effects. COHb blood content, esophageal HMOX-1, Nrf-2, TRPV1 protein, annexin-A1, HIF-1α, IL-1 family, NF-κB, c-Jun, c-Fos, SOCS3 mRNA expressions, and 8-OHdG levels were elevated while PGE₂ concentration was decreased after RE. CO donor-maintained elevated mucosal TRPV1 protein, HIF-1 α, annexin-A1, IL-1RA, SOCS3 mRNA expression, or TGF-β serum content, decreasing 8-OHdG level, and particular inflammatory markers expression/concentration. CORM-2 and Nrf-2/HMOX-1/CO pathway prevent esophageal mucosa against RE-induced lesions, DNA oxidation, and inflammatory response involving HIF-1α, annexin-A1, SOCS3, IL-1RA, TGF-β-modulated pathways. Esophagoprotective and hyperemic CO effects are in part mediated by afferent sensory neurons and TRPV1 receptors activity with questionable COX/PGE₂ or NO/NOS systems involvement.

Identification of Subtypes of Barrett's Esophagus and Esophageal Adenocarcinoma Based on DNA Methylation Profiles and Integration of Transcriptome and Genome Data

BACKGROUND & AIMS

Esophageal adenocarcinomas (EACs) are heterogeneous and often preceded by Barrett's esophagus (BE). Many genomic changes have been associated with development of BE and EAC, but little is known about epigenetic alterations. We performed epigenetic analyses of BE and EAC tissues and combined these data with transcriptome and genomic data to identify mechanisms that control gene expression and genome integrity.

METHODS

In a retrospective cohort study, we collected tissue samples and clinical data from 150 BE and 285 EAC cases from the Oesophageal Cancer Classification and Molecular Stratification consortium in the United Kingdom. We analyzed methylation profiles of all BE and EAC tissues and assigned them to subgroups using non-negative matrix factorization with k-means clustering. Data from whole-genome sequencing and transcriptome studies were then incorporated; we performed integrative methylation and RNA-sequencing analyses to identify genes that were suppressed with increased methylation in promoter regions. Levels of different immune cell types were computed using single-sample gene set enrichment methods. We derived 8 organoids from 8 EAC tissues and tested their sensitivity to different drugs.

RESULTS

BE and EAC samples shared genome-wide methylation features, compared with normal tissues (esophageal, gastric, and duodenum; controls) from the same patients and grouped into 4 subtypes. Subtype 1 was characterized by DNA hypermethylation with a high mutation burden and multiple mutations in genes in cell cycle and receptor tyrosine signaling pathways. Subtype 2 was characterized by a gene expression pattern associated with metabolic processes (ATP synthesis and fatty acid oxidation) and lack methylation at specific binding sites for transcription factors; 83% of samples of this subtype were BE and 17% were EAC. The third subtype did not have changes in methylation pattern, compared with control tissue, but had a gene expression pattern that indicated immune cell infiltration; this tumor type was associated with the shortest time of patient survival. The fourth subtype was characterized by DNA hypomethylation associated with structure rearrangements, copy number alterations, with preferential amplification of CCNE1 (cells with this gene amplification have been reported to be sensitive to CDK2 inhibitors). Organoids with reduced levels of MGMT and CHFR expression were sensitive to temozolomide and taxane drugs.

CONCLUSIONS

In a comprehensive integrated analysis of methylation, transcriptome, and genome profiles of more than 400 BE and EAC tissues, along with clinical data, we identified 4 subtypes that were associated with patient outcomes and potential responses to therapy.

DNA N6-methyladenine increased in human esophageal squamous cell carcinoma

Esophageal cancer is one of the most common malignancies worldwide. DNA N6-methyladenine (6mA) has been well-studied in prokaryotes, while the distribution and biological functions of DNA 6mA in eukaryotic cells remain to be elucidated. Recently, DNA 6mA epigenetic modification was found in human gastric and liver cancers. To explore the status of DNA 6mA epigenetic modification in esophageal cancer, 101 cases of human esophageal squamous cell carcinoma (ESCC) and matched adjacent normal tissue samples were analyzed by dot blot assay. The levels of genomic DNA 6mA were significantly higher in ESCC tissue samples than in matched adjacent normal tissue samples (P<0.001). Increased DNA 6mA was associated with poor tumor differentiation (P<0.05), while no association was found between 6mA modification and gender, age, tumor size, TNM stage, lymph node metastasis, smoking, alcohol intake, or family history (all P>0.05). In conclusion, DNA 6mA epigenetic modification increased in human ESCC and may serve as a prognostic marker.

A Novel Susceptibility Locus Near GRIK2 Associated With Erosive Esophagitis in a Korean Cohort

INTRODUCTION

The male-predominant sex difference through the spectrum of erosive esophagitis to Barrett's esophagus is widely known. We conducted a genome-wide association study (GWAS) stratified by sex for identifying factors that can predict the endoscopically diagnosed erosive esophagitis.

METHODS

Erosive esophagitis was diagnosed by endoscopy and assessed for severity. We identified genetic factors associated with erosive esophagitis that accounted for the sex differences in a cohort of 4,242 participants via a GWAS. After quality control and imputation, genetic associations with erosive esophagitis were investigated by multivariate linear regression in 3,620 subjects. Single-nucleotide polymorphisms (SNPs) with P < 5.0 × 10 were considered significant genome wide, and a genetic risk score was constructed for the prediction of erosive esophagitis risk.

RESULTS

Six genome-wide significant SNPs near the GRIK2 gene on chromosome 6 were found to be associated with erosive esophagitis only in male subjects. These were predictive of severity through a genetic risk score (P < 0.05), and the findings were validated in a cohort of 622 subjects (P < 0.05).

DISCUSSION

This is the first GWAS of erosive esophagitis, and we identified 6 genome-wide significant SNPs in male subjects. These SNPs could help explain the pathogenesis of erosive esophagitis and contribute to the understanding of sex differences. Further genetic investigation could allow for the prediction of high risk for erosive esophagitis and development of new treatment options.

In Barrett's epithelial cells, weakly acidic bile salt solutions cause oxidative DNA damage with response and repair mediated by p38

The frequency of esophageal adenocarcinoma is rising despite widespread use of proton pump inhibitors (PPIs), which heal reflux esophagitis but do not prevent reflux of weakly acidic gastric juice and bile in Barrett's esophagus patients. We aimed to determine if weakly acidic (pH 5.5) bile salt medium (WABM) causes DNA damage in Barrett's cells. Because p53 is inactivated frequently in Barrett's esophagus and p38 can assume p53 functions, we explored p38's role in DNA damage response and repair. We exposed Barrett's cells with or without p53 knockdown to WABM, and evaluated DNA damage, its response and repair, and whether these effects are p38 dependent. We also measured phospho-p38 in biopsies of Barrett's metaplasia exposed to deoxycholic acid (DCA). WABM caused phospho-H2AX increases that were blocked by a reactive oxygen species (ROS) scavenger. WABM increased phospho-p38 and reduced bromodeoxyuridine incorporation (an index of S phase entry). Repair of WABM-induced DNA damage proceeded through p38-mediated base excision repair (BER) associated with reduction-oxidation factor 1-apurinic/apyrimidinic endonuclease I (Ref-1/APE1). Cells treated with WABM supplemented with ursodeoxycholic acid (UDCA) exhibited enhanced p38-mediated responses to DNA damage. All of these effects were observed in p53-intact and p53-deficient Barrett's cells. In patients, esophageal DCA perfusion significantly increased phospho-p38 in Barrett's metaplasia. WABM exposure generates ROS, causing oxidative DNA damage in Barrett's cells, a mechanism possibly underlying the rising frequency of esophageal adenocarcinoma despite PPI usage. p38 plays a central role in oxidative DNA damage response and Ref-1/APE1-associated BER, suggesting potential chemopreventive roles for agents like UDCA that increase p38 activity in Barrett's esophagus.NEW & NOTEWORTHY We found that weakly acidic bile salt solutions, with compositions similar to the refluxed gastric juice of gastroesophageal reflux disease patients on proton pump inhibitors, cause oxidative DNA damage in Barrett's metaplasia that could contribute to the development of esophageal adenocarcinoma. We also have elucidated a critical role for p38 in Barrett's metaplasia in its response to and repair of oxidative DNA damage, suggesting a potential chemopreventive role for agents like ursodeoxycholic acid that increase p38 activity in Barrett's esophagus.

Clinical relevance of esophageal subepithelial activity in eosinophilic esophagitis

Esophageal subepithelial activity (ESEA) is an important determinant of disease severity and complications in eosinophilic esophagitis (EoE). Inflammation and fibrosis of the lamina propria and muscularis propria result in esophageal dysfunction and stricture formation that are clinically manifest by symptoms of dysphagia and food impaction as well as the need for esophageal dilation. Esophageal biopsies that are limited to the evaluation of the esophageal epithelium are an inadequate means to assess overall, clinical disease severity in EoE. Instruments for the assessment of subepithelial activity in EoE are both limited and/or underutilized and thus represent an important unmet clinical need. Studies using endoscopic features, endoscopic ultrasonography, and barium esophagography have demonstrated improvement in ESEA parameters with topical steroid therapy. Impedance planimetry is being evaluated as an objective and quantifiable measure of esophageal distensibility that is a consequence of ESEA. In conjunction with symptom and histologic assessment, evaluation of ESEA provides a more complete evaluation of disease activity in EoE that will enhance clinical care as well as provide insights into the strengths and limitations of therapeutic interventions.

Endoscopic Submucosal Dissection of Seborrheic Keratosis-Like Lesion of the Esophagus: A New Entity?

Seborrheic keratosis, one of the most common lesions of the epidermis, is rarely seen on mucosal surfaces. We report a case of a distinctive epithelial neoplasm of the esophagus showing close resemblance to seborrheic keratosis that was resected with endoscopic submucosal dissection. A 65-year-old patient's previous esophageal biopsy showed suspicious low grade dysplasia and the patient was referred for endoscopic submucosal dissection of a flat lesion in the mid-esophagus. Macroscopic examination revealed a well circumscribed, pigmented and elevated lesion with a diameter of 20 mm. Microscopically, the lesion was well circumscribed, with plaque-like elevation, and showed hyperkeratosis, acanthosis, and papillomatosis. Broad coalescing solid sheets and interconnecting trabeculae of basaloid cells were the consistent feature throughout the lesion. Squamous eddies and occasional central keratinization were present. Mitotic activity and koilocytes were not identified. Immunohistochemically, the lesion showed diffuse nuclear positivity with p63 and negativity with p16. Ki-67 index was confined to the basal cell layer. With the help of histopathologic and immunohistochemical findings, we diagnosed this morphologically benign case as "seborrheic keratosis-like lesion of the esophagus". It should be kept in mind that seborrheic keratosis-like lesions might be rarely seen on mucosal surfaces such as the esophagus. Endoscopic submucosal dissection is a new, curative, and safe endoscopic resection technique in en-bloc resection of superficial esophageal lesions. To our knowledge, this is the first case of the aforementioned lesion in the esophagus being resected with endoscopic submucosal dissection.

Identification of loci of functional relevance to Barrett's esophagus and esophageal adenocarcinoma: Cross-referencing of expression quantitative trait loci data from disease-relevant tissues with genetic association data

Esophageal adenocarcinoma (EA) and its precancerous condition Barrett's esophagus (BE) are multifactorial diseases with rising prevalence rates in Western populations. A recent meta-analysis of genome-wide association studies (GWAS) data identified 14 BE/EA risk loci located in non-coding genomic regions. Knowledge about the impact of non-coding variation on disease pathology is incomplete and needs further investigation. The aim of the present study was (i) to identify candidate genes of functional relevance to BE/EA at known risk loci and (ii) to find novel risk loci among the suggestively associated variants through the integration of expression quantitative trait loci (eQTL) and genetic association data. eQTL data from two BE/EA-relevant tissues (esophageal mucosa and gastroesophageal junction) generated within the context of the GTEx project were cross-referenced with the GWAS meta-analysis data. Variants representing an eQTL in at least one of the two tissues were categorized into genome-wide significant loci (P < 5×10-8) and novel candidate loci (5×10-8 ≤ P ≤ 5×10-5). To follow up these novel candidate loci, a genetic association study was performed in a replication cohort comprising 1,993 cases and 967 controls followed by a combined analysis with the GWAS meta-analysis data. The cross-referencing of eQTL and genetic data yielded 2,180 variants that represented 25 loci. Among the previously reported genome-wide significant loci, 22 eQTLs were identified in esophageal mucosa and/or gastroesophageal junction tissue. The regulated genes, most of which have not been linked to BE/EA etiology so far, included C2orf43/LDAH, ZFP57, and SLC9A3. Among the novel candidate loci, replication was achieved for two variants (rs7754014, Pcombined = 3.16×10-7 and rs1540, Pcombined = 4.16×10-6) which represent eQTLs for CFDP1 and SLC22A3, respectively. In summary, the present approach identified candidate genes whose expression was regulated by risk variants in disease-relevant tissues. These findings may facilitate the elucidation of BE/EA pathophysiology.

Toll-like receptor 2 stimulation augments esophageal barrier integrity

BACKGROUND

Germline-encoded innate immune pattern recognition receptors (PRR) are expressed at epithelial surfaces and modulate epithelial defenses. Evidence suggests that stimulation of the Toll-like receptor (TLR) family of PRR may regulate epithelial barrier integrity by upregulating tight junction (TJ) complex protein expression, but it is not known whether this mechanism is utilized in esophageal epithelial cells. TJ complex proteins maintain intact barrier function and are dysregulated in atopic disorders including eosinophilic esophagitis.

METHODS

Pattern recognition receptors expression was assessed in EoE and control primary esophageal epithelial cells, demonstrating robust expression of TLR2 and TLR3. The three-dimensional air-liquid interface culture (ALI) model was used to test whether TLR2 or TLR3 stimulation alters epithelial barrier function using an in vitro model of human epithelium. Transepithelial electrical resistance (TEER) and FITC-Dextran permeability were evaluated to assess membrane permeability. ALI cultures were evaluated by histology, immunohistochemistry, Western blotting, and chromatin immunoprecipitation (ChIP).

RESULTS

TLR3 stimulation did not change TEER in the ALI model. TLR2 stimulation increased TEER (1.28- to 1.31-fold) and decreased paracellular permeability to FITC-Dextran, and this effect was abolished by treatment with anti-TLR2 blocking antibody. TJ complex proteins claudin-1 and zonula occludens-1 were upregulated following TLR2 stimulation, and ChIP assay demonstrated altered histone 4 acetyl binding at the TJP1 enhancer and CLDN1 enhancer and promoter following zymosan treatment, implying the occurrence of durable chromatin changes.

CONCLUSIONS

Our findings implicate the TLR2 pathway as a potential regulator of esophageal epithelial barrier function and suggest that downstream chromatin modifications are associated with this effect.

Anguillulosis: circumstances of infestation and evolution towards the malignant form

INTRODUCTION

Anguillulosis is a ubiquitous digestive parasitosis. Rare in Tunisia, it is due to a round worm, strongyloid stercoralis, whose natural lodging is the duodeno-jejunal mucosa. Its malignant form is rare but it represents a potentially life-threatening disease.

AIM

We report a case of malignant anguillulosis occurring in a context of immunosuppression.

OBSERVATION

The case we report is about a 46-year-old man treated by a long-term corticosteroid therapy for Takayasu disease. He was hospitalized for an acute digestive syndrome. Biopsies were performed but the evolution was rapidly marked by multiorgan failure, sepsis and death of the patient. Histological analysis of the digestive biopsies concluded to an oeso-gastroduodenal anguillulosis.

CONCLUSION

Anguillulosis is a rare parasitosis but it can pose a health problem especially in its malignant form wich can be a life-threatening.

Risk factors for Mallory-Weiss Tear during endoscopic submucosal dissection of superficial esophageal neoplasms

BACKGROUND

Adverse events during endoscopic submucosal dissection (ESD) of superficial esophageal neoplasms, such as perforation and bleeding, have been well-documented. However, the Mallory-Weiss Tear (MWT) during esophageal ESD remains under investigation.

AIM

To investigate the incidence and risk factors of the MWT during esophageal ESD.

METHODS

From June 2014 to July 2017, patients with superficial esophageal neoplasms who received ESD in our institution were retrospectively analyzed. The clinicopathological characteristics of the patients were collected. Patients were divided into an MWT group and non-MWT group based on whether MWT occurred during ESD. The incidence of MWTs was determined, and the risk factors for MWT were then further explored.

RESULTS

A total of 337 patients with 373 lesions treated by ESD were analyzed. Twenty patients developed MWTs during ESD (5.4%). Multivariate analysis identified that female sex (OR = 5.36, 95%CI: 1.47-19.50, P = 0.011) and procedure time longer than 88.5 min (OR = 3.953, 95%CI: 1.497-10.417, P = 0.005) were independent risk factors for an MWT during ESD. The cutoff value of the procedure time for an MWT was 88.5 min (sensitivity, 65.0%; specificity, 70.8%). Seven of the MWT patients received endoscopic hemostasis. All patients recovered satisfactorily without surgery for the laceration.

CONCLUSION

The incidence of MWTs during esophageal ESD was much higher than expected. Although most cases have a benign course, fatal conditions may occur. We recommend inspection of the stomach during and after the ESD procedure for timely management in cases of bleeding MWTs or even perforation outside of the procedure region.

Eosinophilic esophagitis: Current concepts in diagnosis and treatment

Eosinophilic esophagitis is an immune-allergic pathology of multifactorial etiology (genetic and environmental) that affects both pediatric and adult patients. Its symptoms, which include heartburn, regurgitation, and esophageal stenosis (with dysphagia being more frequent in eosinophilic esophagitis in young adults and children), are similar to those of gastroesophageal reflux disease, causing delays in diagnosis and treatment. Although endoscopic findings such as furrows, esophageal mucosa trachealization, and whitish exudates may suggest its presence, this diagnosis should be confirmed histologically based on the presence of more than 15 eosinophils per high-power field and the exclusion of other causes of eosinophilia (parasitic infections, hypereosinophilic syndrome, inflammatory bowel disease, among others) for which treatment could be initiated. Currently, the 3 “D”s (“Drugs, Diet, and Dilation”) are considered the fundamental components of treatment. The first 2 components, which involve the use of proton pump inhibitors, corticosteroids, immunosuppressants and empirical diets or guided food elimination based on allergy tests, are more useful in the initial phases, whereas endoscopic dilation is reserved for esophageal strictures. Herein, the most important aspects of eosinophilic esophagitis pathophysiology will be reviewed, in addition to evidence for the various treatments.

Issues and controversies in esophageal inlet patch

The proximal esophagus is rarely examined, and its inspection is often inadequate. Optical chromoendoscopy techniques such as narrow band imaging improve the detection rate of inlet patches in the proximal esophagus, a region in which their prevalence is likely underestimated. Various studies have reported correlations between these esophageal marks with different issues such as Barrett's esophagus, but these findings remain controversial. Conflicting reports complicate the process of interpreting the clinical features of esophageal inlet patches and underestimate their importance. Unfortunately, the limited clinical data and statistical analyses make reaching any conclusions difficult. It is hypothesized that inlet patches are correlated with various esophageal and extraesophageal symptoms, diagnoses and the personalized therapeutic management of patients with inlet patches as well as the differential diagnosis for premalignant lesions or early cancers. Due to its potential underdiagnosis, there are no consensus guidelines for the management and follow up of inlet patches. This review focuses on questions that were raised from published literature on esophageal inlet patches in adults.

Nuclear magnetic resonance-based metabolomics and metabolic pathway networks from patient-matched esophageal carcinoma, adjacent noncancerous tissues and urine

BACKGROUND

Several studies have demonstrated a correlation between esophageal cancer (EC) and perturbed urinary metabolomic profiles, but none has described the correlation between urine metabolite profiles and those of the tumor and adjacent esophageal mucosa in the same patient.

AIM

To investigate how urinary metabolic phenotypes were linked to the changes in the biochemical landscape of esophageal tumors.

METHODS

Nuclear magnetic resonance-based metabolomics were applied to esophageal tumor tissues and adjacent normal mucosal tissues alongside patient-matched urine samples.

RESULTS

Analysis revealed that specific metabolite changes overlapped across both metrics, including glucose, glutamate, citrate, glycine, creatinine and taurine, indicating that the networks for metabolic pathway perturbations in EC, potentially involved in but not limited to disruption of fatty acid metabolism, glucose and glycolytic metabolism, tricarboxylic acid cycle and glutaminolysis. Additionally, changes in most urinary biomarkers correlated with changes in biomarker candidates in EC tissues, implying enhanced energy production for rapid cell proliferation.

CONCLUSION

Overall, these associations provide evidence for distinct metabolic signatures and pathway disturbances between the tumor tissues and urine of EC patients, and changes in urinary metabolic signature could reflect reprogramming of the aforementioned metabolic pathways in EC tissues. Further investigation is needed to validate these initial findings using larger samples and to establish the underlying mechanism of EC progression.

Prevalence and risk factors for Barrett’s esophagus in Taiwan

BACKGROUND

Barrett’s esophagus (BE) is a pre-malignant condition associated with the development of esophageal adenocarcinoma. The prevalence of BE in the general populations of Asian countries ranges from 0.06% to 1%. However, with lifestyle changes in Asian countries and adoption of western customs, the prevalence of BE might have increased.

AIM

To determine the current prevalence of BE in Taiwan, and to investigate risk factors predicting the presence of BE.

METHODS

This retrospective study was conducted at the Health Evaluation Center of Kaohsiung Veterans General Hospital in Taiwan. Between January 2015 and December 2015, 3385 subjects undergoing routine esophagogastroduodenoscopy examinations as part of a health check-up at the Health Evaluation Center were included. Patient characteristics and endoscopic findings were carefully reviewed. Lesions with endoscopic findings consistent with BE awaiting histological evaluation were judged as endoscopically suspected esophageal metaplasia (ESEM). BE was defined based on extension of the columnar epithelium ≥ 1 cm above the gastroesophageal junction and was confirmed based on the presence of specialized intestinal metaplasia (IM) in the metaplastic esophageal epithelium. Clinical factors of subjects with BE and subjects without BE were compared, and the risk factors predicting BE were analyzed.

RESULTS

A total of 3385 subjects (mean age, 51.29 ± 11.42 years; 57.1% male) were included in the study, and 89 among them were confirmed to have IM and presence of goblet cells via biopsy examination. The majority of these individuals were classified as short segment BE (n = 85). The overall prevalence of BE was 2.6%. Multivariate analysis disclosed that old age [odds ratio (OR) = 1.033; 95% confidence interval (CI): 1.012-1.055; P = 0.002], male gender (OR = 2.106; 95%CI: 1.145-3.872; P = 0.017), ingestion of tea (OR = 1.695; 95%CI: 1.043-2.754; P = 0.033), and presence of hiatal hernia (OR = 3.037; 95%CI: 1.765-5.225; P < 0.001) were significant risk factors predicting BE. The independent risk factor for the presence of IM in ESEM lesions was old age alone (OR = 1.029; 95%CI: 1.006-1.053; P = 0.014).

CONCLUSION

Current prevalence of BE among the general population in Taiwan is 2.6%. Old age, male gender, ingestion of tea and hiatal hernia are significant risk factors for BE.

Alteration of the esophageal microbiota in Barrett's esophagus and esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has increased in recent decades, and its 5-year survival rate is less than 20%. As a well-established precursor, patients with Barrett's esophagus (BE) have a persistent risk of progression to EAC. Many researchers have already identified some factors that may contribute to the development of BE and EAC, and the identified risks include gastroesophageal reflux (GER), male sex, older age, central obesity, tobacco smoking, Helicobacter pylori (H. pylori) eradication, and the administration of proton pump inhibitors (PPIs) and antibiotics. The human gut harbors trillions of microorganisms, the majority of which are bacteria. These microorganisms benefit the human host in many ways, such as helping in digestion, assisting in the synthesis of certain vitamins, promoting the development of the gastrointestinal immune system, regulating metabolism and preventing invasion by specific pathogens. In contrast, microbial dysbiosis may play important roles in various diseases, such as inflammation and cancers. The composition of the microbiota located in the normal esophagus is relatively conserved without distinct microbial preferences in the upper, middle and lower esophagus. Six major phyla constitute the esophageal microbiota, including Firmicutes, Bacteroides, Actinobacteria, Proteobacteria, Fusobacteria and TM7, similar to the oral microbiota. Streptococcus dominates the esophageal microbiota. However, the microbiota varies in different esophageal diseases compared to that in the healthy esophagus. The type I microbiota, which is primarily composed of gram-positive bacteria, is closely associated with the normal esophagus, while type II microbiota has enriched gram-negative bacteria and is mainly associated with the abnormal esophagus. These increased gram-negative anaerobes/microaerophiles include Veillonella, Prevotella, Haemophilus, Neisseria, Granulicatella and Fusobacterium, many of which are associated with BE. The microbial diversity in the esophagus is decreased in EAC patients, and Lactobacillus fermentum is enriched compared to that in controls and BE patients. Furthermore, the microbiota may be associated with BE and EAC by interacting with their risk factors, including central obesity, GER, H. pylori, administration of PPIs and antibiotics. Therefore, a large gap in research must be bridged to elucidate the associations among these factors. Some studies have already proposed several potential mechanisms by which the microbiota participates in human carcinogenesis by complicated interactions with the human host immune system and signaling pathways. The activation of the LPS-TLR4-NF-κB pathway may contribute to inflammation and malignant transformation. This exciting field of gastrointestinal microbiota allows us to unravel the mystery of carcinogenesis from another perspective. Further studies are needed to explore whether the microbiota changes before or after disease onset, to improve our understanding of the pathogenesis, and to find novel targets for prevention, diagnosis and therapy, which could offer more cost-effective and relatively safe choices.

Cytokeratin 19 Immunostain Reduces Variability in Grading Epithelial Dysplasia of the Non-Keratinized Upper Aerodigestive Tract Mucosa

Epithelial dysplasia (ED) grading systems are criticized for low reliability. The effects of diagnostic tests or stains on reducing examiner variability in grading ED of the upper aerodigestive tract have not been investigated. The study aim was to examine the effectiveness of cytokeratin 19 (K19) immunostain on enhancing inter and intraexaminer reliability of ED grading and to reiterate the relation of K19 positivity with epithelial keratinization. The study sample consisted of 122 paraffin blocks that fulfilled the inclusion criteria. Each paraffin block had three sections cut: one immunostained for K19 and two for hematoxylin and eosin stain (H&E). Each examiner graded the study sample in six rounds; three using H&E stain only and three using paired K19-H&E stains. The study examiners were three American-Board certified practicing oral pathologists. The results were analyzed using Krippendorff's alpha, ROC curve, Chi square test and binary logistic regression. Upon the use of paired K19-H&E stains the results showed that the intraexaminer reliability coefficients of grading were improved from 0.70, 0.69, 0.78 to 0.73, 0.88, 0.91 for examiners 1, 2, and 3 respectively. Reliability coefficients for inter-examiners improved from 0.55 to 0.73 (Krippendorff alpha). The accuracy of identifying the diseased cases (high-grade dysplasia) increased from 0.82 to 0.94 (ROC curve). Binary logistic regression revealed that K19 positivity is negatively associated with hyperkeratinization of surface epithelium (P = 0.001). To conclude, for grading non-keratinized epithelial dysplastic lesions of the upper aerodigestive tract, paired K19-H&E stains proved to reduce inter and intra-examiner variability by highlighting the extension of dysplastic epithelial cells within epithelial thickness, thus identifying the involved epithelial third and assigning a more reliable and better reproducible grade.

Racial Disparity in the Sex Distribution, the Prevalence, and the Incidence of Dysplasia in Barrett's Esophagus

GOALS

Our aim was to study the prevalence of dysplasia and progression to high-grade dysplasia (HGD) and esophageal adenocarcinoma (EAC) in African Americans (AA) with Barrett's esophagus (BE) and compare it with that of non-Hispanic white (NHW) controls.

BACKGROUND

BE, a precursor of EAC, is a disease of predominantly white men and is uncommon in AA. The prevalence of dysplasia and progression to HGD and EAC in AA patients with BE is not clearly known.

STUDY

All AA or NHW patients with confirmed BE, that is specialized intestinal metaplasia, seen between 2002 and 2013 at our institution were included. Variables such as age, gender, medication use, the body mass index, the date of endoscopy, the hiatal hernia size, the BE length, and histologic findings were noted. Progression to HGD/EAC was evaluated.

RESULTS

Fifty-two AA and 2394 NHW patients with BE were identified. There was a higher percentage of women in the AA cohort (46.2%) than in the NHW cohort (24.9%, P<0.001). Nondysplastic BE was more prevalent in AA than in NHW (80.8% vs. 68.4%, P=0.058). In the surveillance cohort of 20 AA and 991 NHW, no racial differences in progression to HGD/EAC were observed during a median follow-up of 43 months.

CONCLUSIONS

This study includes the largest number of AA with histologically confirmed BE reported so far. About 46.2% of the AA cohort with BE in our study consisted of women. There was a trend toward a higher prevalence of nondysplastic BE in AA compared with NHW.

KLF4 activates NFκB signaling and esophageal epithelial inflammation via the Rho-related GTP-binding protein RHOF

Understanding the regulatory mechanisms within esophageal epithelia is essential to gain insight into the pathogenesis of esophageal diseases, which are among the leading causes of morbidity and mortality throughout the world. The zinc-finger transcription factor Krüppel-like factor (KLF4) is implicated in a large number of cellular processes, such as proliferation, differentiation, and inflammation in esophageal epithelia. In murine esophageal epithelia, Klf4 overexpression causes chronic inflammation which is mediated by activation of NFκB signaling downstream of KLF4, and this esophageal inflammation produces epithelial hyperplasia and subsequent esophageal squamous cell cancer. Yet, while NFκB activation clearly promotes esophageal inflammation, the mechanisms by which NFκB signaling is activated in esophageal diseases are not well understood. Here, we demonstrate that the Rho-related GTP-binding protein RHOF is activated by KLF4 in esophageal keratinocytes, leading to the induction of NFκB signaling. Moreover, RHOF is required for NFκB activation by KLF4 in esophageal keratinocytes and is also important for esophageal keratinocyte proliferation and migration. Finally, we find that RHOF is upregulated in eosinophilic esophagitis, an important esophageal inflammatory disease in humans. Thus, RHOF activation of NFκB in esophageal keratinocytes provides a potentially important and clinically-relevant mechanism for esophageal inflammation and inflammation-mediated esophageal squamous cell cancer.

The retrospective comparison between submucosal tunneling endoscopic resection and endoscopic submucosal excavation for managing esophageal submucosal tumors originating from the muscularis propria layer

BACKGROUND

Submucosal tunneling endoscopic resection (STER) and endoscopic submucosal excavation (ESE) were recently introduced to cure submucosal tumors (SMTs) originating from the muscularis propria (MP) layer. This study aimed to compare clinical performance and safety of STER and ESE in treating esophageal SMTs originating from the MP layer.

METHODS

From January 2011 to December 2017, retrospective data collection and follow-up were applied for all STER or ESE cases with esophageal SMTs originating from the MP layer in our endoscopy center, including clinical characteristics, procedure success, efficacy, and adverse events. Subgroup analysis was further done based on tumor size and origin.

RESULTS

90 STER and 77 ESE were enrolled in this study. There were no significant difference for  patient characteristics, procedure performance, and complications for ESE and STER intervention (P > 0.05). STER was faster than ESE (3.90 mm²/min vs 2.82 mm²/min, P < 0.05). For large tumors (≥ 20 mm), both techniques had the similar performance (P > 0.05), while STER led to the shorter hospitalization (4.0d vs 7.0d, P < 0.05) and lower postoperative complication (16.3% vs 45.5%, P < 0.05). For small tumors (< 20 mm), STER achieved faster operation (STER vs ESE, 2.57 mm²/min vs 1.83 mm²/min, P < 0.05). Regardless of tumor origin, there were no significant difference for both techniques, but STER resulted in short hospitalization for SMTs from the deep MP layer (STER vs ESE, 5.0d vs 7.0d, P < 0.05). During the follow-up, 2 residual and 4 recurrence occurred in the STER group, as well as 1 residual and 2 recurrence in the ESE group.

CONCLUSIONS

Both STER and ESE were effective for treating esophageal SMTs originating from the MP layer. STER might be better due to its faster operation, less complications, and shorter hospitalization.

A thin layer of sucrose octasulfate protects the oesophageal mucosal epithelium in reflux oesophagitis

Sucralfate is effective for the treatment of gastric and duodenal ulcers owing to its protective gel-forming ability. However, the mechanism by which sucralfate protects the oesophageal mucosa against reflux oesophagitis has not been clarified. We aimed to investigate the mechanisms of action of sucralfate and sucrose octasulfate (SOS), a component of sucralfate. SOS and sucralfate were administered to oesophagitis-induced rats, and the ulcer lesion size was macroscopically examined and scored. Effective pepsin activity in the gastric juices obtained from the animal model was evaluated by a casein digestion test. Sucralfate and SOS improved the pathology scores in a dose-dependent manner, whereas gastric juice pepsin activity was not impaired by therapeutic doses of SOS. As SOS lacks the ability to form a thick gel layer by polymerisation, we examined the distribution of SOS in the mucosal lumen by imaging mass spectrometry (IMS) to determine whether SOS directly adheres to the mucosal surface. A clear homogeneous thin-layer SOS film (>100 μm thick) was visualized on the oesophageal mucosal surface. Moreover, this SOS film formation was enhanced at ulcer lesion sites. Taken together, SOS appears to protect oesophageal mucosa against reflux oesophagitis via thin-layer formation on the mucosal surface.