Requirement of Gαq/Gα11 Signaling in the Preservation of Mouse Intestinal Epithelial Homeostasis

Background & AimsProliferation, differentiation, and morphogenesis of the intestinal epithelium are tightly regulated by a number of molecular pathways. Coordinated action of intestine is achieved by gastrointestinal hormones, most of which exert these actions through G-protein–coupled receptors. We herein investigated the role of Gαq/11-mediated signaling in intestinal homeostasis.MethodsIntestinal tissues from control (Gnaqflox/floxGna11+/+), Int-Gq knock-out (KO) (VilCre+/-Gnaqflox/floxGna11+/+), G11 KO (Gnaqflox/floxGna11-/-), and Int-Gq/G11 double knock-out (DKO) (VilCre+/-Gnaqflox/floxGna11-/-) mice were examined by microscopy, transmission electron microscopy, and immunohistochemistry. The effect of Gαq/11-mediated signaling was studied in the cell lineage, proliferation, and apoptosis. Dextran sodium sulfate (DSS) colitis was induced to study the role of Gαq/11 in colon.ResultsPaneth cells were enlarged, increased in number, and mislocalized in Int-Gq/G11 DKO small intestine. Paneth cells also reacted with PAS and Muc2 antibody, indicating an intermediate character of Paneth and goblet cells. The nuclear β-catenin, T-cell factor 1, and Sox9 expression were reduced severely in the crypt base of Int-Gq/G11 DKO intestine. Proliferation was activated in the crypt base and apoptosis was enhanced along the crypt. Int-Gq/G11 DKO mice were susceptible to DSS colitis. Proliferation was inhibited in the crypt of unaffected and regenerative areas. Cystic crypts, periodic acid–Schiff–positive cells, and Muc2-positive cells were unusually observed in the ulcerative region.ConclusionsThe Gαq/11-mediated pathway plays a pivotal role in the preservation of intestinal homeostasis, especially in Paneth cell maturation and positioning. Wnt/β-catenin signaling was reduced significantly in the crypt base in Gαq/G11-deficient mice, resulting in the defective maturation of Paneth cells, induction of differentiation toward goblet cells, and susceptibility to DSS colitis

Efficacy of Combined Mesalazine Plus Corticosteroid Enemas for Diversion Colitis after Subtotal Colectomy for Ulcerative Colitis

Diversion colitis is a benign inflammatory process that occurs in any part of the large bowel excluded from the fecal stream by a diverting colostomy. While most of the patients with diversion colitis usually are asymptomatic, a minority has abdominal pain and rectal discharge of blood or mucus. A 65-year-old Japanese man was diagnosed as having diversion colitis with ulcerative colitis at 4 months after subtotal colectomy. Corticosteroid and mesalazine enemas were started nonsynchronously. A proctoscopy after 2 months showed no response. Prednisolone injections were started at 1.0 mg/kg daily, but the mucosal inflammation still failed to improve. A combined mesalazine 1 g plus prednisolone sodium phosphate 20 mg enema was started once daily. The rectal bleeding and endoscopic findings improved. Finally proctectomy and ileal pouch-anal anastomosis were successfully performed. A combined mesalazine plus corticosteroid enema may be effective in patients with diversion colitis associated with ulcerative colitis

The Diagnosis of Small Gastrointestinal Subepithelial Lesions by Endoscopic Ultrasound-Guided Fine Needle Aspiration and Biopsy

Endoscopic ultrasonography (EUS) has been widely accepted in the diagnosis of all types of tumors, especially pancreatic tumors, lymph nodes, and subepithelial lesions (SELs). One reason is that the examination can provide a detailed observation, with tissue samples being immediately obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Many SELs are detected incidentally during endoscopic examinations without symptoms. Most SELs are mesenchymal tumors originating from the fourth layer, such as gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas. GISTs are potentially malignant. Surgical treatment is recommended for localized GISTs of ≥20 mm. However, the indications for the diagnosis and follow-up of GISTs of <20 mm in size are controversial. There are several reports on the rapid progression or metastasis of small GISTs. Therefore, it is important to determine whether a SEL is a GIST or not. The main diagnostic method is EUS-FNA. Recently, endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) using a new biopsy needle has been reported to obtain larger tissue samples. Additionally, various biopsy methods have been reported to have a high diagnostic rate for small GISTs. In local gastric SELs, regardless of the tumor size, EUS can be performed first; then, EUS-FNA/B or various biopsy methods can be used to obtain tissue samples for decision-making in relation to therapy and the follow-up period

Construction of a preoperative scoring system to predict the difficulty level of colorectal endoscopic submucosal dissection.

BACKGROUND:We attempted to examine the factors contributing to the difficulty in performance of colorectal ESD, with the aim of constructing a scoring system that could help in prediction of the difficulty level of the procedure. METHODS AND MATERIALS:The data were analyzed from two viewpoints: to determine the factors contributing to 1) non-en bloc resection and the factors contributing to 2) a slow resection speed. Factors falling under these two categories contributing to difficulty in performance of ESD were extracted and used to construct a scoring system. The validity of this scoring system was evaluated by calculating the correlation between the score and the resection speed in a different dataset. RESULTS:Based on the results of our analysis, we assigned scores for various factors as follows: 4 points for EMR of a scarred lesion, 1 point for tumors with a diameter of ≥ 30 mm, 2 points for lesions located in the liver/splenic flexure, 1 point for lesions located in the transverse colon, 3 points for LST-NG-PD/depressed lesions, 1 point for protruded lesions and LST-NG-F lesions (range 0-10). In the validation study, the rank correlation coefficient between the score according to the scoring system and the resection speed was -0.130, representing a weak and negative correlation (P = 0.03). We defined the difficulty level depending on the sum of the scores: 0-2, low difficulty level; 3-5, intermediate difficulty level; ≥ 6, high difficulty level. The average resection speed was 12.6 mm2/min in the group with scores of 0-2, 8.1 mm2/min in the group with scores of 3-5, and 5.5 mm2/min in the group with scores of ≥ 6 (11.2 mm2/min in all lesions). CONCLUSION:Our colorectal ESD scoring system would be useful for selection of operators with the appropriate skill level in the procedure for colorectal ESD cases

MCP-1 INHIBITS DNA SYNTHESIS IN RAT PANCREATIC STELLATE CELLS

Activated pancreatic stellate cells (PSCs) synthesize various kinds of cytokines and chemokines including monocyte chemoattractant protein-1 (MCP-1) and play major roles in promoting inflammation and fibrogenesis in the pancreas. MCP-1 is a potent chemotactic factor for leukocytes and it has recently been shown that the target is not restricted. The aim of this study was to investigate whether MCP-1 exerts a biological effect on PSCs. Cultured rat PSCs secreted MCP1 independent of the concentration of transforming growth factor-β1 (TGF-β 1) in the culture media. Although PSCs lack the typical receptor system (C-C chemokine receptor 2 (CCR2)), MCP-1 inhibited DNA synthesis in PSCs without activation, suggesting the presence of CCR2-independent MCP-1 signaling pathway. Further, MCP-1 inhibited the proliferation of PSCs in which TGF-β 1/Smad pathway was blocked by the dominant-negative Smad2/3 over-expression. MCP-1 did not affect the phosphorylation state of mitogen-activated protein kinase (MAPK), Akt, nor epidermal growth factor receptor (EGFR). Taken together, MCP-1 inhibited DNA synthesis of cultured rat PSCs in an autocrine or paracrine manner without activation and this effect was exerted through CCR2-independent and TGF-β1/Smad-independent pathway. These data provide new insights to better understand MCP-1 participation in pancreatic inflammation and also to develop a new strategy for its treatment

Should Emergency Endoscopy be Performed in All Patients With Suspected Colonic Diverticular Hemorrhage?

Objective: We attempted to develop a scoring system for facilitating decision making regarding the performance of emergency endoscopy in patients with colonic diverticular hemorrhage. Methods: This study involved analysis of the data of 178 patients who presented with hematochezia and were diagnosed as having colonic diverticular hemorrhage by colonoscopy. The patients were divided into 2 groups depending on whether the bleeding source was identified or not at the initial endoscopy (source-identified and source-not-identified groups), and on the basis of the results obtained, we established a scoring system for predicting successful identification of the bleeding source. Results: The percentages of patients on oral anticoagulant therapy or with a Charlson comorbidity index of ≥6, serum C-reactive protein level of ≥1 mg/dL, or extravasation of contrast medium visualized on contrast-enhanced computed tomographic (CT) images were all significantly higher in the identified than in the nonidentified group. Multivariate analysis identified extravasation of contrast medium on contrast-enhanced CT images (odds ratio [OR]: 10.6; 95% confidence interval [CI]: 2.7-42.2) and use of anticoagulants (OR: 4.5; 95% CI: 1.5-13.5) as independent predictors of successful identification of the bleeding source at the initial endoscopy in patients with colonic diverticular hemorrhage. On the basis of these results, we established a scoring system, which showed a sensitivity of 80% and specificity of 81% for successful identification of the bleeding source at the initial endoscopy. Conclusions: Herein, we propose a scoring system as a useful tool for determining whether emergency endoscopy is indicated in individual patients with suspected colonic diverticular hemorrhage