Goichi Uno

Notch signaling pathway and Cdx2 expression in the development of Barrett's esophagus

Cdx2 expression in esophageal stem cells induced by reflux bile acids may be an important factor for development of Barretts esophagus, whereas Notch signaling is a molecular signaling pathway that plays an important role in the determination of cell differentiation. ATOH1 (a factor associated with Notch signaling) plays an important role in differentiation of stem cells into goblet cells. However, the relationship between the Notch signaling pathway and Cdx2 expression in the development of Barretts esophagus has not been explored. The aim of this study was to investigate the interrelationship between Notch signaling and Cdx2 in esophageal epithelial cells. The expressions of Cdx2, MUC2, and intracellular signaling molecules related to Notch signaling (Notch1, Hes1, and ATOH1) were examined using real-time polymerase chain reaction (PCR) and immunohistochemical staining with biopsy specimens obtained from esophageal intestinal metaplasia (IM) with goblet cells (IM(+)) and columnar epithelium not accompanied by goblet cells (IM(−)). For in vitro experiments, we employed human esophageal epithelial cell lines (OE33, OE19, and Het-1A). After forced Cdx2 expression by applying a Cdx2 expression vector to the cells, changes in the expressions of Notch1, Hes1, ATOH1, Cdx2, and MUC2 were analyzed by real-time PCR and western blot analysis. Changes in expressions of Notch1, Hes1, ATOH1, Cdx2, and MUC2 in cells were analyzed following stimulation with bile acids in the presence or absence of Cdx2 blocking with Cdx2-siRNA. Suppressed Hes1 and enhanced ATOH1 and MUC2 expressions were identified in IM(+) specimens. Forced expression of Cdx2 in cells suppressed Hes1, and enhanced ATOH1 and MUC2 expressions, whereas bile acids suppressed Hes1, and enhanced ATOH1, Cdx2, and MUC2 expressions. On the other hand, these effects were blocked by siRNA-based Cdx2 downregulation. Enhanced expression of Cdx2 by stimulation with bile acids may induce intestinal differentiation of esophageal columnar cells by interaction with the Notch signaling pathway.

Prevalence of gastroesophageal reflux disease in children, adults, and elderly in the same community.

The prevalence of gastroesophageal reflux disease (GERD) in adults is increasing in Japan as well as worldwide likely due to increasing obesity and the decreasing rate of Helicobacter pylori infection. However, data regarding the prevalence of GERD in children and adolescents in Japan are lacking. We investigated the prevalence of GERD in children, adults, and elderly living in the same community.

Clinical features of eosinophilic esophagitis: differences between Asian and Western populations.

The prevalence and incidence of eosinophilic esophagitis (EoE) have been rapidly increasing in Western countries. It is thought to be more common among Caucasians than other racial or ethnic groups, but epidemiological studies have not been fully evaluated in Asian populations, and its clinical manifestation is rarely documented. In this review, recent reports regarding EoE in Asian countries have been collected, and differences in the clinical features, including symptoms and endoscopic findings, between Asian and Western populations have been evaluated. In Asia, EoE is still much less prevalent than in Western countries. Baseline values for average age, male/female ratio, and personal history of allergic disease were comparable to those in Western populations. Predominant symptoms were dysphagia, and food impaction was extremely rare among Asian patients. Although the frequency of abnormal endoscopic findings varies among studies, over 90% of patients with EoE have shown abnormal findings such as linear furrow, which is the most common findings, in recent prospective studies in Asia. There are few reports regarding the treatment of EoE and no prospective studies evaluating drugs or elimination diet in patient with EoE have been reported in Asia. Overall, EoE had similar clinical characteristics in Asian populations. Because the incidence of EoE could increase in the future with the increase in allergic disorders in Asian countries, large‐scale, nationwide prospective studies should be performed to more fully understand the epidemiology and pathophysiology of EoE in Asian populations.

Fatty acid synthase expression in Barrett's esophagus: implications for carcinogenesis.

Goals To investigate the relationship between fatty acid synthase (FASN) expression and the clinicopathological characteristics of Barretts esophagus and its carcinogenesis. Background FASN, a key enzyme of the fatty acid biosynthetic pathway, is overexpressed not only in various types of cancer, but also in premalignant conditions. Therefore, FASN overexpression is considered to be indicative of a possible premalignant stage. Study Patients (N=354) with endoscopically and histologically proven Barretts esophagus were enrolled. Mucin phenotyping of Barretts esophagus, expression of FASN and COX-2, cellular proliferation, and apoptosis were evaluated immunohistochemically in biopsy samples, and factors influencing FASN expression were determined by multivariate logistic regression analysis. To evaluate if gastric reflux induces FASN expression, esophageal adenocarcinoma cells were treated with bile acid and low pH, and the effect of a FASN inhibitor on cell proliferation was assessed. Results Expression of FASN protein was observed in 52.2% of patients with Barretts esophagus by immunohistochemistry; this expression pattern was retained in esophageal adenocarcinoma. Intestinal mucin phenotype, COX-2, increased stromal angiogenesis, and elevated proliferating cell nuclear antigen index were confirmed to be positive independent factors for FASN expression. In the esophageal adenocarcinoma cell line SEG-1, FASN mRNA was induced by bile acid with low pH. Cell proliferation was strongly suppressed by the FASN inhibitor C75. Conclusions FASN is strongly expressed in the intestinal mucin phenotype of Barretts esophagus, in which Barretts glandular cells display elevated cellular proliferation, angiogenesis, and COX-2 expression. Exposure of the lower esophagus to bile acid with low pH may induce FASN in Barretts esophagus.

Endoscopic characteristics of short-segment Barrett's esophagus, focusing on squamous islands and mucosal folds.

Background and Aim:  Endoscopic definitions of Barretts esophagus (BE) vary among countries, mainly because of the difficulty in diagnosing short‐segment BE (SSBE) endoscopically. The aim of this study was to investigate whether the endoscopic identification of squamous islands and the specific position of columnar epithelium helps improve the diagnosis of SSBE.

Bile acids induce Delta-like 1 expression via Cdx2-dependent pathway in the development of Barrett’s esophagus

Crosstalk between the Notch signaling pathway and Caudal-related homeobox 2 (Cdx2) has important roles in the development of Barrett’s esophagus (BE). We investigated the expression and function of the Notch signaling ligand Delta-like 1 (Dll1) during the development of BE. We determined the expression levels of Dll1 and intracellular signaling molecules related to Notch signaling ((Notch1, Hairy/enhancer of split 1 (Hes1), and Atonal homolog 1 (ATOH1)) in human esophageal squamous and Barrett’s epithelium samples. Next, those expression levels in esophageal squamous cells (Het-1A) and Barrett’s esophageal cells (CP-A and BAR-T) following stimulation with either bile acids or gamma-secretase inhibitor were investigated. Finally, changes in those expression levels following transfection of a Cdx2 or Dll1 expression vector into Het-1A cells were examined. In addition, changes in those expression levels following knockdown of Cdx2 or Dll1 in CP-A cells were also examined. Dll1 was found to be upregulated and localized in the cell membrane and cytoplasm in BE. Bile acids enhanced cytoplasmic expression of Dll1 in CP-A cells, while cleaved Notch1 expression did not change, suggesting lack of a Dll1 agonistic effect on Notch signaling. Cells transfected with Cdx2 revealed significantly enhanced Dll1, while forced expression of Dll1 enhanced ATOH1, Cdx2, and MUC2 expression levels. Nevertheless, enhanced Dll1 did not induce Hes1 expression, suggesting that Dll1 may primarily function as an intracellular signaling molecule and not a Notch agonistic ligand in the canonical pathway. In addition, knockdown of Cdx2 completely abrogated any increase in Dll1 expression upon treatment with bile acids. Our results revealed a novel function of Dll1: facilitation of intestinal metaplasia in conjunction with Cdx2 expression. Furthermore, they suggest that intracellular induction of Dll1 expression in esophageal epithelial cells due to Cdx2 induction in response to bile acids has important roles in BE development.

Pathophysiology of Barrett's Esophagus-Associated Neoplasia: Circumferential Spatial Predilection

The prevalence rates of Barretts esophagus (BE) and esophageal adenocarcinoma (EAC) arising from BE show striking geographic patterns as they are much more common in Western as compared with Asian countries. However, recent epidemiological studies indicate that the number of patients with BE and EAC are gradually increasing in Asia including Japan, corresponding to the increase in prevalence of gastroesophageal reflux disease (GERD). Because the prognosis of patients with advanced-stage EAC remains poor, early detection of neoplastic lesion in those with BE has led to recent interest in effective treatment. Several promising studies have revealed that early neoplasia in BE is mainly located in the right anterior wall of the distal esophagus. Interestingly, this endoscopic characteristic has been found in both Western and Japanese populations. Potential pathophysiologic explanations underlying the circumferential distribution of neoplasia in BE include a nonuniform asymmetric distribution of esophageal acid exposure, with a tendency toward mucosal acid-related injury on the right side of the esophageal wall in patients with GERD, and the functional structure of the lower esophageal sphincter. Findings of the present study should improve lesion detection and aid in developing a target biopsy protocol for surveillance of BE.

Novel stenting method for malignant right colonic stenosis using ultra-thin endoscopy: Report of four cases

Placement of a self‐expandable metallic stent (SEMS) is recognized as a safe and effective procedure for patients with malignant severe colonic stenosis. However, reports of this stent for right‐sided colonic stenosis are limited, possibly as a result of technical difficulties. We report a new method for delivering SEMS to the site of right‐sided colonic stenosis in four patients with malignant right‐sided colonic stenosis. Technical success was obtained with sequential use of a double‐balloon endoscope and ultrathin endoscope, while we also injected non‐ionic contrast agent into the submucosal layer as a marker for stenting under fluoroscopy. There were no adverse events noted during the procedure and clinical improvement was seen in all four cases. In conclusion, SEMS placement for right‐sided malignant colonic stenosis with our newly developed method appears to be safe and effective, and can be used for decompression of the right colon.

Impact of the composition of gastric reflux bile acids on Barrett's oesophagus.

BACKGROUND The effect of the composition of reflux bile acids, especially the ratio of hydrophobic to hydrophilic ones, on the development of Barretts oesophagus has not been fully investigated in human studies. AIMS To evaluate the influence of the bile acid composition of gastric juice on Barretts oesophagus, a prospective study was designed. METHODS Fifty patients with and 100 patients without Barretts oesophagus were enrolled. For all enrolled patients, gastric juice was collected by the endoscopic procedure for bile acid analysis. The ratio of hydrophobic to hydrophilic bile acids (bile hydrophobicity ratio, BHR) was calculated from 6 kinds of bile acids analysed in gastric juice. The relationship between the ratio and clinico-pathological factors of Barretts oesophagus was investigated. RESULTS The mean of BHR of patients with Barretts oesophagus was significantly higher than that of patients without Barretts oesophagus (0.26 ± 0.05 vs. 0.08 ± 0.02, p<0.05). In multivariate analysis, a high BHR value was a predictor for the presence of Barretts oesophagus (OR 5.74, p<0.001). In patients with Barretts oesophagus, the BHR correlated with COX-2 protein expression and with accelerated cellular proliferation. CONCLUSIONS Patients with Barretts oesophagus had a higher BHR in the gastric juice than those without.

Interobserver variation in the endoscopic diagnosis of gastroduodenal ulcer scars: implications for clinical management of NSAIDs users

BackgroundA clinical history of peptic ulcer has been reported to be associated with a high rate of ulcer recurrence in nonsteroidal anti-inflammatory drug (NSAID) users. Therefore, it is a very important issue to precisely know the previous history prior to NSAIDs administration. To clarify the possible difficulty to identify the history, we determined the sensitivity and diagnostic concordance of endoscopy for the identification of ulcer scars indicative of previous clinical history of peptic ulcer diseases.MethodsThe first study enrolled 200 consecutive patients with a clinical history of gastric or duodenal ulcers previously confirmed by esophagogastroduodenoscopy. The sensitivity of endoscopy for identifying scars was determined for these patients. In the second study, the extent of interobserver agreement was determined for 47 endoscopists who identified ulcer scars in endoscopic photographs of 30 sites of previous active gastric ulcers and 30 sites of previous active duodenal ulcers. The kappa coefficient of reliability was calculated to measure the interobserver agreement on the diagnosis of ulcer scars.ResultsOut of 190 patients eligible for analysis, 104 (54.7%) were found to have gastric or duodenal ulcer scars on endoscopy; there were no gastric or duodenal ulcer scars seen in the remaining patients (45%). In the second study, the kappa values for endoscopic diagnosis of gastric and duodenal ulcer scars were 0.14 (95% CI 0.13-0.16) and 0.29 (95% CI 0.27-0.32), respectively. The addition of indigo-carmine chromoendoscopy did not provide a statistically significant improvement in diagnostic concordance in patients with gastric ulcer scar since the kappa value for chromoendoscopic diagnosis was 0.15; 95% CI 0.13-0.17 as low as for un-contrasted scars.ConclusionsThe sensitivity and concordance of endoscopic diagnosis of gastric and duodenal ulcer scars are not satisfactory for the use of endoscopy only to identify previous ulcer disease. To avoid the overlooking the previous clinical history of peptic ulcer diseases, the diagnosis of peptic ulcer scar has to be carefully done prior to NSAIDs administration.