Protective role of M3 muscarinic acetylcholine receptor in indomethacin-induced small intestinal injury.

EP4 prostanoid receptor (EP4R) contributes to the intestinal epithelial Cl- secretion, and inhibition of prostaglandin E (PGE) production by non-steroidal anti-inflammatory drugs (NSAIDs) plays a central role in NSAID-induced enteropathy. Although M3 muscarinic acetylcholine receptor (M3R) also contributes to the intestinal epithelial Cl- secretion, it remains unclear whether M3R is involved in NSAID-induced enteropathy due to a lack of selective agents. The present study explored how M3R is involved in the regulation of the intestinal epithelial Cl- secretion and its pathophysiological role in NSAID-induced enteropathy. Using the novel highly-selective M3 positive allosteric modulator PAM-369 that we recently developed, we evaluated the role of M3R in the intestinal epithelial secretion ex vivo by measuring the short circuit current (Isc) of intestinal epithelium with a Ussing chamber system and examined whether or not M3R protects against small intestinal injury in indomethacin-treated mice. Both the PGE1 derivative misoprostol and carbachol similarly increased the Isc in a concentration-dependent manner. The Isc increases were abolished either by receptor antagonists (an EP4R antagonist and a M3R antagonist, respectively) or by removal of extracellular Cl-. PAM-369 enhanced the carbachol-induced Isc by potentiating M3R, which could contribute to enhanced intestinal epithelial secretion. Treatment with PAM-369 ameliorated small intestinal injury in indomethacin-treated mice. Importantly, the M3R expression was significantly up-regulated, and PAM-369 potentiation of M3R was augmented in indomethacin-treated mice compared to untreated mice. These findings show that M3R plays a role in maintaining the intestinal epithelial secretion, which could contribute to protection against indomethacin-induced small intestinal injury. M3R is a promising target for treating or preventing NSAID-induced enteropathy. KEY MESSAGES: PAM-369, the M3 positive allosteric modulator, was used to potentiate M3R. PAM-369 enhanced carbachol-induced Isc in mouse ileum. PAM-369 ameliorated small intestinal injury in indomethacin-treated mice. M3R is a promising target for treating or preventing NSAID-induced enteropathy.

Evidence-based clinical guidelines for chronic constipation 2023.

In July 2023 the Japan Gastroenterological Association published the first version of its clinical guidelines for chronic constipation 2023. Based on the latest evidence, these guidelines describe the definition, classification, diagnostic criteria, diagnostic testing methods, epidemiology, pathophysiology, and treatment of chronic constipation. They include flowcharts for both diagnosis and treatment of chronic constipation. In the treatment of chronic constipation, the first step involves differentiating between secondary forms, such as organic disease-associated constipation, systemic disease-associated constipation, and drug-induced constipation. The next step is to determine whether the chronic constipation stems from a motility disorder, a form of primary chronic constipation. For functional constipation and constipation-predominant irritable bowel syndrome, treatment should be initiated after evaluating symptoms like reduced frequency of bowel movement frequency type or defecation difficulty type. The first line of treatment includes improvement of lifestyle habits and diet therapy. The first drugs to consider for oral treatment are osmotic laxatives. If these are ineffective, secretagogues and ileal bile acid transporter inhibitors are candidates. However, stimulant laxatives are exclusively designated for as-needed use. Probiotics, bulk-forming laxatives, prokinetics, and Kampo medicine, for which there is insufficient evidence, are considered alternative or complementary therapy. Providing the best clinical strategies for chronic constipation therapy in Japan, these clinical guidelines for chronic constipation 2023 should prove useful for its treatment worldwide.

Cancer risk by length of Barrett's esophagus in Japanese population: a nationwide multicenter retrospective cohort study.

BACKGROUND: The cancer risk for each length of Barrett's esophagus (BE) in Japanese is unknown. This nationwide, multi-institutional study aims to clarify the cancer risk by length of BE in the general Japanese population. METHODS: Consecutive subjects who underwent upper endoscopic screening at 17 centers between 2013 and 2017 and had at least one follow-up endoscopy by December 2022 were included. The presence/absence of BE and, if present, its length were retrospectively assessed using the retrieved endoscopic images recorded at baseline. Information on the subsequent occurrence of esophageal adenocarcinoma and other upper gastrointestinal cancers was also collected. Cancer incidence was calculated and expressed as %/year. RESULTS: A total of 33,478 subjects were enrolled, and 17,884 (53.4%), 10,641 (31.8%), 4889 (14.6%), and 64 (0.2%) were diagnosed as absent BE, BE < 1 cm, 1-3 cm, and ≥ 3 cm, respectively. During a median follow-up of 80 months, 11 cases of esophageal adenocarcinoma developed. The annual incidence of esophageal adenocarcinoma is 0%/year for absent BE, 0.0032 (0.00066-0.013)%/year for BE < 1 cm, 0.026 (0.011-0.054)%/year for 1-3 cm, and 0.58 (0.042-2.11)%/year for ≥ 3 cm, respectively. Meanwhile, the incidence of esophageal squamous cell carcinoma and gastric cancer were 0.039 (0.031-0.049)%/year and 0.16 (0.14-0.18)%/year, respectively. CONCLUSIONS: By enrolling a large number of subjects with long-term follow-up, this study demonstrated that the risk of cancer increased steadily with increasing length of BE in the Japanese population. Therefore, it is important to consider the length of BE when determining the management strategy for BE.

Clinicopathological significance of microsatellite instability and immune escape mechanism in patients with gastric solid-type poorly differentiated adenocarcinoma.

BACKGROUND: In gastric solid-type poorly differentiated adenocarcinoma (PDA), the role of microsatellite instability and immune escape mechanism remains unclear. The current study aimed to elucidate the clinical significance of mismatch repair (MMR) status, genome profile, C-X-C motif chemokine receptor 2 (CXCR2) expression, and myeloid-derived suppressor cell (MDSC) infiltration in solid-type PDA. METHODS: In total, 102 primary solid-type PDA cases were retrieved, and classified into 46 deficient-MMR (dMMR) and 56 proficient-MMR (pMMR) cases based on immunohistochemistry (IHC) and polymerase chain reaction-based molecular testing results. The mRNA expression profiles (NanoString nCounter Assay) of stage-matched dMMR (n = 6) and pMMR (n = 6) cases were examined. The CXCR2 expression and MDSC infiltration (CD11b- and CD33-positive cells) were investigated via IHC in all solid-type PDA cases. RESULTS: mRNA analysis revealed several differentially expressed genes and differences in biological behavior between the dMMR (n = 46) and pMMR (n = 56) groups. In the multivariate analysis, the dMMR status was significantly associated with a longer disease-free survival (hazard ratio = 5.152, p = 0.002) and overall survival (OS) (hazard ratio = 5.050, p = 0.005). CXCR2-high expression was significantly correlated with a shorter OS in the dMMR group (p = 0.018). A high infiltration of CD11b- and CD33-positive cells was significantly correlated with a shorter OS in the pMMR group (p = 0.022, 0.016, respectively). CONCLUSIONS: dMMR status can be a useful prognostic predictor, and CXCR2 and MDSCs can be novel therapeutic targets in patients with solid-type PDA.

The interplay between alterations in esophageal microbiota associated with Th17 immune response and impaired LC20 phosphorylation in achalasia.

BACKGROUND: Achalasia is an esophageal motility disorder with an unknown etiology. We aimed to determine the pathogenesis of achalasia by studying alterations in esophageal smooth muscle contraction and the associated inflammatory response, and evaluate the role of esophageal microbiota in achalasia development. METHODS: We analyzed esophageal mucosa and lower esophageal sphincter (LES) samples, obtained from patients with type II achalasia who underwent peroral endoscopic myotomy. Esophageal conditioned media obtained from patients were transferred into the mouse esophagus to determine whether the esophageal intraluminal environment is associated with achalasia. RESULTS: Approximately 30% of 20-kDa myosin light chains (LC20) was phosphorylated in LES from the control group under resting and stimulated conditions, whereas less than 10% of LC20 phosphorylation was detected in achalasia under all conditions. The hypophosphorylation of LC20 in achalasia was associated with the downregulation of the myosin phosphatase-inhibitor protein CPI-17. Th17-related cytokines, including IL-17A, IL-17F, IL-22, and IL-23A, were significantly upregulated in achalasia. α-Diversity index of esophageal microbiota and the proportion of several microbes, including Actinomyces and Dialister, increased in achalasia. Actinomyces levels positively correlated with IL-23A levels, whereas Dialister levels were positively associated with IL-17A, IL-17F, and IL-22 levels. Esophageal IL-17F levels increased in mice after oral administration of the conditioned media. CONCLUSIONS: In LES of patients with achalasia, hypophosphorylation of LC20, a possible cause of impaired contractility, was associated with CPI-17 downregulation and an increased Th17-related immune response. The esophageal intraluminal environment, represented by the esophageal microbiota, could be associated with the development and exacerbation of achalasia.

Comparison of hemostatic ability between spray coagulation and forced coagulation modes in endoscopic submucosal dissection in patients with early gastric neoplasms: a study protocol for multicenter randomized controlled trial (Spray-G trial).

BACKGROUND: Endoscopic submucosal dissection (ESD) is the standard treatment for early gastric neoplasms (EGN). Controlling intraoperative bleeding is crucial for ensuring safe and reliable procedures. ESD using the spray coagulation mode (SCM-ESD) has been developed to control bleeding more effectively than ESD using the conventional forced coagulation mode (FCM-ESD). This study aims to compare the hemostatic efficacies of SCM-ESD and FCM-ESD. METHODS: This multicenter, prospective, parallel, randomized, open-label superiority trial will be conducted in five Japanese institutions. Patients with a preoperative diagnosis of intramucosal EGC will be randomized to undergo either SCM-ESD or FCM-ESD. The primary outcome measure is the completion of ESD with an electrosurgical knife alone, without the use of hemostatic forceps. Secondary outcomes include the number and duration of hemostasis using hemostatic forceps, procedure time, curability, and safety. A total of 130 patients will be enrolled in this study. DISCUSSION: This trial will provide evidence on the hemostatic efficacy of SCM-ESD compared with FCM-ESD in patients with intramucosal EGN, potentially improving the safety and reliability of ESD procedures. TRIAL REGISTRATION: The trial has been registered at the University Hospital Medical Information Network Clinical Trials Registration (UMIN-CTR) as UMIN000040518. The reception number is R000054009.

Development of a new endoscopy system to visualize bilirubin for the diagnosis of duodenogastroesophageal reflux.

OBJECTIVES: Reflux hypersensitivity (RH) is a form of refractory gastroesophageal reflux disease in which duodenogastroesophageal reflux (DGER) plays a role. This study aimed to determine the usefulness of an endoscopy system equipped with image-enhanced technology for evaluating DGER and RH. METHODS: The image enhancement mode for detecting bilirubin and calculated values were defined as the Bil mode and Bil value, respectively. First, the visibility of the Bil mode was validated for a bilirubin solution and bile concentrations ranging from 0.01% to 100% (0.002-20 mg/dL). Second, visibility scores of the Bil mode, when applied to the porcine esophagus sprayed with a bilirubin solution, were compared to those of the blue laser imaging (BLI) and white light imaging (WLI) modes. Third, a clinical study was conducted to determine the correlations between esophageal Bil values and the number of nonacid reflux events (NNRE) during multichannel intraluminal impedance-pH monitoring as well as the utility of esophageal Bil values for the differential diagnosis of RH. RESULTS: Bilirubin solution and bile concentrations higher than 1% were visualized in red using the Bil mode. The visibility score was significantly higher with the Bil mode than with the BLI and WLI modes for 1% to 6% bilirubin solutions (P < 0.05). The esophageal Bil value and NNRE were significantly positively correlated (P = 0.031). The area under the receiver operating characteristic curve for the differential diagnosis of RH was 0.817. CONCLUSION: The Bil mode can detect bilirubin with high accuracy and could be used to evaluate DGER in clinical practice.

Evaluating the efficacy and safety of acotiamide in patients with esophagogastric junction outflow obstruction: study protocol for an investigator-initiated, multi-center, randomized, double-blind, placebo-controlled phase II trial.

BACKGROUND: We have determined that the impaired accommodation of the lower esophageal sphincter (LES) underlies the pathogenesis of esophagogastric junction outflow obstruction (EGJOO). We have also found that acotiamide may treat EGJOO by improving impaired LES accommodation. The effects of acotiamide in patients with EGJOO need to be further confirmed in a prospective study. METHODS: This trial is a multicenter, randomized, double-blind, placebo-controlled study to compare the efficacy and safety of acotiamide (300 mg/day or 600 mg/day) with those of a placebo in the treatment of patients with EGJOO. The primary endpoint will be the proportion of patients who report an improvement in symptom of food sticking in the chest after 4 weeks of treatment period 1. The secondary endpoints will be the proportion of patients with normalized integrated relaxation pressure (IRP), the value of change from baseline in the distal contractile integral, basal LES pressure, EGJOO-quality of life score, Gastrointestinal Symptom Rating Scale, and the correlation between IRP and each symptom score. During the 2-year trial period, 42 patients from five institutions will be enrolled. DISCUSSION: This trial will provide evidence to clarify the efficacy and safety of acotiamide as a treatment for patients with EGJOO. Acotiamide might help improve the quality of life of patients with EGJOO and is expected to prevent the progression of EGJOO to achalasia. TRIAL REGISTRATION: This study was approved by the Institutional Review Board (IRB) of Kyushu University Hospital as well as the local IRBs of the participating sites for clinical trials and registered in the Japan Registry of Clinical Trials (jRCT: 2071210072). The registration date is on October 11, 2021.

Importance of preoperative total colonoscopy and endoscopic resection after self-expandable metallic stent placement for obstructive colorectal cancer as a bridge-to-surgery.

BACKGROUND AND AIM: Colonic self-expandable metallic stent (SEMS) placement enables preoperative total colonoscopy (TCS) in patients with obstructive colorectal cancer. Following SEMS placement, it is possible to assess the presence or absence of synchronous proximal colon cancers and perform preoperative endoscopic resection (ER) for neoplastic lesions proximal to the primary lesion. The objective of this study was to determine the usefulness and safety of preoperative TCS and ER after SEMS placement in patients with obstructive colorectal cancer. METHODS: From April 2016 to March 2022, we enrolled 100 patients with obstructive colorectal cancer who underwent SEMS placement, including 86 patients who underwent preoperative TCS after SEMS placement. Complications associated with preoperative TCS and ER after SEMS placement and the characteristics of the neoplastic lesions were assessed. RESULTS: The success rate of SEMS placement as bridge-to-surgery was 98.0%; six patients had associated complications. Preoperative TCS was performed 8 (range: 1-30) days after SEMS placement. Four patients had synchronous advanced cancers. Nine non-advanced synchronous cancers, 116 adenomas, and 18 sessile-serrated lesions were treated by preoperative TCS and ER after SEMS placement. No procedure-related complications, namely stent migration, bleeding, and perforation were observed. Forty-five patients underwent follow-up TCS 1 year after surgery. Only one patient with submucosal invasive cancer required a second surgery. CONCLUSIONS: Preoperative TCS and ER after SEMS placement was performed with no complications. This approach allows preoperative evaluation of the entire colon and the treatment of precancerous lesions. (240 words).

Gastric cancer presenting with ramucirumab-related gastrocolic fistula successfully managed by colonic stenting: a case report.

We report a rare case of gastric cancer presenting with a gastrocolic fistula during ramucirumab and paclitaxel combination therapy that was successfully managed with colonic stenting. A 75-year-old man was admitted to our hospital with the chief complaint of melena. Esophagogastroduodenoscopy revealed a large ulcerated tumor in the lower stomach, judged by laparoscopy as unresectable (sT4bN1M0). After four cycles of first-line chemotherapy with S-1 plus oxaliplatin, the patient showed disease progression, and second-line therapy with ramucirumab and paclitaxel was started. At the end of the third cycle, the patient had gastric antral stenosis, which necessitated the placement of a gastroduodenal stent. When the patient complained of diarrhea 10 days later, esophagogastroduodenoscopy revealed a fistula between the greater curvature of the stomach and the transverse colon. The fistula was covered by double colonic stenting, with a covered metal stent placed within an uncovered metal stent, after which leakage from the stomach to the colon stopped.