Xiaoxin Chen

Intestinal metaplasia recurs infrequently in patients successfully treated for Barrett's esophagus with radiofrequency ablation.

OBJECTIVES:Radiofrequency ablation (RFA) of Barretts esophagus (BE) is safe and effective in eradicating dysplasia and intestinal metaplasia, and may reduce rates of esophageal adenocarcinoma (EAC). We assessed rates of and risk factors for disease recurrence after successful treatment of BE with RFA.METHODS:We performed a retrospective cohort study of patients who completed RFA for dysplastic BE or intramucosal carcinoma (IMC), achieved complete eradication of dysplasia (CE-D) or intestinal metaplasia (CE-IM), and underwent subsequent endoscopic surveillance at a single center. Rates of disease recurrence and progression were determined. Patients with and without recurrent disease were compared to determine risk factors for recurrence.RESULTS:Two hundred and sixty-two subjects underwent RFA during the study period. Of these, 119 and 112 patients were retained in endoscopic surveillance after CE-D and CE-IM, respectively. Median observation time was 397 days (range: 54–1,668 days). Eight patients (7% of those with CE-IM) had recurrent disease after a median of 235 days (range 55–1,124 days). Progression to IMC (n=1) or EAC (n=2) occurred in three of these eight patients, all of whom had pre-ablation high-grade dysplasia (HGD). Five patients had recurrence of non-dysplastic BE (n=3), low-grade dysplasia (n=1), and HGD (n=1). During 155 patient-years of observation, recurrence occurred in 5.2%/year, and progression occurred in 1.9%/year. No clinical characteristics were associated with disease recurrence.CONCLUSIONS:In patients with BE and dysplasia or early cancer who achieved CE-IM, BE recurred in ∼5%/year. Patient characteristics did not predict recurrence. Subjects undergoing RFA for dysplastic BE should be retained in endoscopic surveillance.

Tryptase staining of mast cells may differentiate eosinophilic esophagitis from gastroesophageal reflux disease

OBJECTIVES:Mast cells may contribute to the pathogenesis of eosinophilic esophagitis (EoE), but their role in diagnosis is unknown. Our aim was to determine whether tryptase staining of esophageal mast cells differentiates EoE from gastroesophageal reflux disease (GERD) and has utility for diagnosis of EoE.METHODS:We performed a case–control study comparing patients with EoE, defined by consensus guidelines, to GERD patients with eosinophils on esophageal biopsy. Immunohistochemistry was performed with mast cell tryptase. The density (mast cells/mm2) and intensity (0–4 scale) of mast cell staining was compared between groups after masking the diagnosis. Receiver operating characteristic (ROC) curves were constructed, and the area under the curve (AUC) was calculated to assess mast cell staining as both a stand-alone diagnostic test and an adjunctive assay with eosinophil counts.RESULTS:Fifty-four EoE (mean age 24 years; 69% male; mean 146 eosinophils per high-power field (eos/hpf)) and 55 GERD (mean age 34 years; 60% male; mean 20 eos/hpf) patients were analyzed. The maximum epithelial tryptase density was higher in EoE than in GERD (162±87 mast cells/mm2 vs. 67±54; P<0.001). Mast cells were diffusely distributed throughout the biopsy in more EoE than GERD patients (41 vs. 7%; P<0.001). Tryptase density and eosinophil count were only weakly correlated (R2=0.09; P=0.002). The AUC was 0.84 for tryptase staining alone, and 0.96 for the combination of mast cells and eosinophils.CONCLUSIONS:Patients with EoE have higher levels of tryptase-positive mast cells compared with GERD patients, improving the diagnostic value of biopsies beyond eosinophil counts alone. Mast cell tryptase may have utility as a diagnostic assay for EoE.

Markers of Eosinophilic Inflammation for Diagnosis of Eosinophilic Esophagitis and Proton Pump Inhibitor–Responsive Esophageal Eosinophilia: A Prospective Study

BACKGROUND & AIMS Distinguishing between eosinophilic esophagitis (EoE), gastroesophageal reflux disease, and proton pump inhibitor-responsive esophageal eosinophilia (PPI-REE) is challenging. We assessed whether immunohistochemical analysis of esophageal tissues for major basic protein (MBP), eotaxin-3, and tryptase can be used for diagnosis of EoE and to differentiate EoE from PPI-REE. METHODS We conducted a prospective study of 196 consecutive adults who underwent outpatient endoscopy at the University of North Carolina from 2009 through 2012. Incident cases of EoE were diagnosed per consensus guidelines. Patients with gastroesophageal reflux disease or dysphagia served as controls. PPI-REE was defined as a symptomatic and histologic response to a PPI. Immunohistochemistry was performed to quantify MBP, eotaxin-3, and tryptase. The maximum density of epithelial staining was determined for each assay; levels were compared between EoE and control groups and then EoE and PPI-REE groups, and receiver operating characteristic curves were constructed. RESULTS Esophageal tissues from patients with EoE (n = 50) had a median 951 MBP-positive cells/mm(2), whereas those from controls (n = 123) had a median 2 MBP-positive cells/mm(2) (P < .001). Samples from patients with EoE had a median 155 eotaxin-3-positive cells/mm(2), and those from controls (n = 123) had 18 eotaxin-3-positive cells/mm(2) (P < .001). Samples from patients with EoE had a median 249 tryptase-positive cells/mm(2), and those from controls (n = 123) had 11 tryptase-positive cells/mm(2) (P < .001). Levels of MBP, eotaxin-3, tryptase, and the combination of all 3 identified patients with EoE with area under the receiver operating characteristic curve values of 0.99, 0.94, 0.99, and 1.00. Analyses of only samples with eosinophil counts of 10-100 eosinophils per high-power field produced similar results. No marker distinguished EoE from PPI-REE. Esophageal tissues from patients with PPI-REE (n = 23) had 987 MBP-positive cells/mm(2) (P = .18, compared with EoE), 160 eotaxin-3-positive cells/mm(2) (P = .33), and 243 tryptase-positive cells/mm(2) (P = .28). CONCLUSIONS Esophageal tissues from patients with EoE have substantially higher levels of MBP, eotaxin-3, and tryptase than controls on the basis of immunohistochemical analysis. Assays for the 3 markers identify patients with EoE with 100% accuracy but cannot distinguish EoE from PPI-REE.

Diagnostic Utility of Major Basic Protein, Eotaxin-3, and Leukotriene Enzyme Staining in Eosinophilic Esophagitis

OBJECTIVES:Features of eosinophilic esophagitis (EoE) and gastroesophageal reflux disease (GERD) overlap. We aimed to determine whether staining for tissue biomarkers would differentiate EoE from GERD, suggesting utility for diagnosis of EoE.METHODS:In this case–control study, EoE patients defined by consensus guidelines were compared to GERD patients with eosinophils on esophageal biopsy. Immunohistochemistry was performed for major basic protein (MBP), eotaxin-3, leukotriene A4 hydrolase (LTA4H), and leukotriene C4 synthase (LTC4S). After masking, the maximum staining density (cells per mm2) was quantified for each marker and compared between groups. Receiver operator characteristic curves were constructed, and the area under the curve (AUC) calculated to assess the diagnostic utility of each of the biomarkers alone and in combination with eosinophil counts.RESULTS:There were 51 EoE cases (mean age 24; mean 143 eosinophils per high-power field (eos per h.p.f.)) and 54 GERD controls (mean age 34; mean 20 eos per h.p.f.). The MBP density was higher in EoE than in GERD (1479 vs. 59 cells per mm2; P<0.001), as was the eotaxin-3 density (2219 vs. 479; P<0.001). There were no differences for LTA4H and LTC4S. MBP density and eosinophil count correlated (R=0.81; P<0.001); correlation with eotaxin-3 was weaker (R=0.25; P=0.01). The AUC for diagnosis of EoE was 0.96 for MBP, 0.87 for eotaxin-3, 0.58 for LTA4H, 0.66 for LTC4S, and 0.99 for the combination of MBP, eotaxin-3, and eosinophil count.CONCLUSIONS:Patients with EoE had substantially higher levels of MBP and eotaxin-3 staining than GERD patients. These markers may have utility as a diagnostic assay for EoE.

Safety and efficacy of endoscopic mucosal therapy with radiofrequency ablation for patients with neoplastic Barrett's esophagus.

BACKGROUND & AIMS The goal of radiofrequency ablation (RFA) for patients with Barretts esophagus (BE) is to eliminate dysplasia and metaplasia. The efficacy and safety of RFA for patients with BE and neoplasia are characterized incompletely. METHODS We performed a retrospective study of 244 patients treated with RFA for BE with dysplasia or intramucosal carcinoma. Efficacy outcomes were complete eradication of intestinal metaplasia (CEIM), complete eradication of dysplasia, total treatments, and RFA sessions. Safety outcomes included death, perforation, stricture, bleeding, and hospitalization. We identified factors associated with incomplete EIM and stricture formation. RESULTS CEIM was achieved in 80% of patients, and complete eradication of dysplasia was achieved in 87%; disease progressed in 4 patients. A higher percentage of patients with incomplete EIM were female (40%) than those with CEIM (20%; P = .045); patients with incomplete EIM also had a longer segment of BE (5.5 vs 4.0 cm; P = .03), had incomplete healing between treatment sessions (45% vs 15%; P = 0.004), and underwent more treatment sessions (4 vs 3; P = .007). Incomplete healing was associated independently with incomplete EIM. Twenty-three patients (9.4%) had a treatment-related complication during 777 treatment sessions (3.0%), including strictures (8.2%), postprocedural hemorrhages (1.6%), and hospitalizations (1.6%). Patients who developed strictures were more likely to use nonsteroidal anti-inflammatory drugs than those without strictures (70% vs 45%; P = .04), have undergone antireflux surgery (15% vs 3%; P = .04), or had erosive esophagitis (35% vs 12%; P = .01). CONCLUSIONS RFA is highly effective and safe for treatment of BE with dysplasia or early stage cancer. Strictures were the most common complications. Incomplete healing between treatment sessions was associated with incomplete EIM. Nonsteroidal anti-inflammatory drug use, prior antireflux surgery, and a history of erosive esophagitis predicted stricture formation.

Focal endoscopic mucosal resection before radiofrequency ablation is equally effective and safe compared with radiofrequency ablation alone for the eradication of Barrett's esophagus with advanced neoplasia

BACKGROUND EMR is commonly performed before radiofrequency ablation (RFA) for nodular dysplastic Barretts esophagus (BE). OBJECTIVE To determine the efficacy and safety of EMR before RFA for nodular BE with advanced neoplasia (high-grade dysplasia [HGD] or intramucosal carcinoma [IMC]). DESIGN Retrospective study. SETTING University of North Carolina Hospitals, from 2006 to 2011. PATIENTS 169 patients with BE with advanced neoplasia: 65 patients treated with EMR and RFA for nodular disease and 104 patients treated with RFA alone for nonnodular disease. INTERVENTIONS EMR, RFA. MAIN OUTCOME MEASUREMENTS Efficacy (complete eradication of dysplasia, complete eradication of intestinal metaplasia, total treatment sessions, RFA treatment sessions), safety (stricture formation, bleeding, and hospitalization). RESULTS EMR followed by RFA achieved complete eradication of dysplasia and complete eradication of intestinal metaplasia in 94.0% and 88.0% of patients, respectively, compared with 82.7% and 77.6% of patients, respectively, in the RFA-only group (P = .06 and P = .13, respectively). The complication rates between the 2 groups were similar (7.7% vs 9.6%, P = .79). Strictures occurred in 4.6% of patients in the EMR-before-RFA group. compared with 7.7% of patients in the RFA-only group (P = .53). LIMITATIONS Retrospective study at a tertiary-care referral center. CONCLUSION In patients treated with EMR before RFA for nodular BE with HGD or IMC, no differences in efficacy and safety outcomes were observed compared with RFA alone for nonnodular BE with HGD or IMC. EMR followed by RFA is safe and effective for patients with nodular BE and advanced neoplasia.

Differential gene expression in normal esophagus and Barrett's esophagus.

PurposeAs the premalignant lesion of human esophageal adenocarcinoma (EAC), Barrett’s esophagus (BE) is characterized by intestinal metaplasia in the normal esophagus (NE). Gene expression profiling with microarray and serial analysis of gene expression (SAGE) may help us understand the potential molecular mechanism of human BE.MethodsWe analyzed three microarray datasets (two cDNA arrays and one oligonucleotide array) and one SAGE dataset with statistical tools, significance analysis of microarrays (SAM) and SAGE(Poisson), to identify individual genes differentially expressed in BE. Gene set enrichment analysis (GSEA) was used to identify a priori defined sets of genes that were differentially expressed. These gene sets were grouped according to either certain signaling pathways (GSEA curated), or the presence of consensus binding sequences of known transcription factors (GSEA motif). Immunohistochemical staining (IHC) was used to validate differential gene expression.ResultsBoth SAM and SAGE(Poisson) identified 68 differentially expressed genes (55 BE genes and 13 NE genes) with an arbitrary cutoff ratio (≥4-fold). With IHC on matched pairs of NE and BE tissues from 6 patients, these genes were grouped into 6 categories: category I (25 genes only expressed in BE), category II (5 genes only expressed in NE), category III (8 genes expressed more in BE than in NE), and category IV (2 genes expressed more in NE than in BE). Differential expression of the remaining genes was not confirmed by IHC either due to false discovery (category V), or lack of proper antibodies (category VI). Besides individual genes, the TGFβ pathway and several transcription factors (CDX2, HNF1, and HNF4) were identified by GSEA as enriched pathways and motifs in BE. Apart from 9 target genes known to be up-regulated in BE, IHC staining confirmed up-regulation of 19 additional CDX1 and CDX2 target genes in BE.ConclusionOur data suggested an important role of CDX1 and CDX2 in the development of BE. The IHC-confirmed gene list will lead to future studies on the molecular mechanism of BE.

Molecular Mechanisms of Barrett’s Esophagus

Barrett’s esophagus (BE) is defined as the metaplastic conversion of esophageal squamous epithelium to intestinalized columnar epithelium. As a premalignant lesion of esophageal adenocarcinoma (EAC), BE develops as a result of chronic gastroesophageal reflux disease (GERD). Many studies have been conducted to understand the molecular mechanisms of this disease. This review summarizes recent results involving squamous and intestinal transcription factors, signaling pathways, stromal factors, microRNAs, and other factors in the development of BE. A conceptual framework is proposed to guide future studies. We expect elucidation of the molecular mechanisms of BE to help in the development of improved management of GERD, BE, and EAC.

Nrf2 deficiency impairs the barrier function of mouse oesophageal epithelium.

Objective As a major cellular defence mechanism, the Nrf2/Keap1 pathway regulates expression of genes involved in detoxification and stress response. Here we hypothesise that Nrf2 is involved in oesophageal barrier function and plays a protective role against gastro-oesophageal reflux disease (GERD). Design Human oesophageal biopsy samples, mouse surgical models and Nrf2−/− mice were used to assess the role of the Nrf2/Keap1 pathway in oesophageal barrier function. Trans-epithelial electrical resistance (TEER) was measured with mini-Ussing chambers. HE staining and transmission electron microscopy were used to examine tissue morphology, while gene microarray, immunohistochemistry, western blotting and chromatin immunoprecipitation (ChIP) analysis were used to assess gene expression. Results Nrf2 was expressed in normal oesophageal epithelium and activated in GERD of both humans and mice. Nrf2 deficiency and gastro-oesophageal reflux in mice, alone or in combination, reduced TEER and increased intercellular space in oesophageal epithelium. Nrf2 target genes and gene sets associated with oxidoreductase activity, mitochondrial biogenesis and energy production were downregulated in the oesophageal epithelium of Nrf2−/− mice. Consistent with the antioxidative function of Nrf2, a DNA oxidative damage marker (8OHdG) dramatically increased in oesophageal epithelial cells of Nrf2−/− mice compared with those of wild-type mice. Interestingly, ATP biogenesis, Cox IV (a mitochondrial protein) and Claudin 4 (Cldn4) expression were downregulated in the oesophageal epithelium of Nrf2−/− mice, suggesting that energy-dependent tight junction integrity was subject to Nrf2 regulation. ChIP analysis confirmed the binding of Nrf2 to Cldn4 promoter. Conclusions Nrf2 deficiency impairs oesophageal barrier function through disrupting energy-dependent tight junction.

Zebrafish K5 promoter driven GFP expression as a transgenic system for oral research

The zebrafish has become a useful model organism for research on development and diseases. However, there has been no zebrafish model system for studying oral carcinogenesis. In the present study, we first characterized the histology of the upper gastrointestinal tract of zebrafish. We found that zebrafish tongue was covered by a non-keratinized stratified squamous epithelium, which was similar to the oro-esophageal epithelium in humans. In situ hybridization showed that keratin 5, a marker of the basal cell layer of mammalian oral epithelium, was expressed in the squamous epithelium of zebrafish tongue. A highly conserved promoter of zebrafish keratin 5 was cloned to drive transgenic expression of GFP. GFP was found to be expressed in the periderm of embryos. In adult fish, GFP was also abundantly expressed in the tongue and fin. GFP expression in transgenic fish recapitulated endogenous zebrafish keratin 5 gene expression as shown by in situ hybridization. This study indicated a high fidelity of GFP reporter gene expression in the tongue under the control of zebrafish keratin 5 promoter. This zebrafish transgenic model system may be used for future studies on oral development and cancer.