Mamoru Takenaka

Neonatal Fc receptor for IgG (FcRn) expressed in the gastric epithelium regulates bacterial infection in mice

Neonatal Fc receptors for immunoglobulin (Ig)G (FcRn) assume a central role in regulating host IgG levels and IgG transport across polarized epithelial barriers. We have attempted to elucidate the contribution of FcRn in controlling Helicobacter infection in the stomach. C57BL/6J wild-type or FcRn−/− mice were infected with Helicobacter heilmannii, and gastric lesions, bacterial load and the levels of antigen-specific IgG in serum and gastric juice were analyzed. The elevated levels of anti-H. heimannii IgG in gastric juice were observed exclusively in wild-type mice but not in FcRn−/− mice. In contrast, an increase in lymphoid follicles and bacterial loads along with deeper gastric epithelium invasion were noted in FcRn−/− mice. C57BL/6J wild-type or FcRn−/− mice were also infected with Helicobacter pylori SS1, and the results of the bacterial load in stomachs of these mice and the anti-H. pylori IgG levels in serum and gastric juice were similar to those from H. heilmannii infection. Our data suggest that FcRn can be functionally expressed in the stomach, which is involved in transcytosis of IgG, and prevent colonization by H. heilmannii and the associated pathological consequences of infection.

Prospective evaluation of digital single-operator cholangioscope for diagnostic and therapeutic procedures (with videos)

Recently, the digital single‐operator cholangioscope (SPY‐DS) has become available. This system may allow diagnosis by direct visualization and allow performance of various therapeutic procedures. The aim of the present study was to prospectively evaluate the clinical utility of DSOCS for diagnostic and therapeutic procedures for biliary disease.

Gankyrin induces STAT3 activation in tumor microenvironment and sorafenib resistance in hepatocellular carcinoma.

Most hepatocellular carcinomas (HCC) develop as a result of chronic liver inflammation. We have shown that the oncoprotein gankyrin is critical for inflammation‐induced tumorigenesis in the colon. Although the in vitro function of gankyrin is well known, its role in vivo remains to be elucidated. We investigated the effect of gankyrin in the tumor microenvironment of mice with liver parenchymal cell‐specific gankyrin ablation (Alb‐Cre;gankyrinf/f) and gankyrin deletion both in liver parenchymal and non‐parenchymal cells (Mx1‐Cre;gankyrinf/f). Gankyrin upregulates vascular endothelial growth factor expression in tumor cells. Gankyrin binds to Src homology 2 domain‐containing protein tyrosine phosphatase‐1 (SHP‐1), mainly expressed in liver non‐parenchymal cells, resulting in phosphorylation and activation of signal transducer and activator of transcription 3 (STAT3). Gankyrin deficiency in non‐parenchymal cells, but not in parenchymal cells, reduced STAT3 activity, interleukin (IL)‐6 production, and cancer stem cell marker (Bmi1 and epithelial cell adhesion molecule [EpCAM]) expression, leading to attenuated tumorigenic potential. Chronic inflammation enhances gankyrin expression in the human liver. Gankyrin expression in the tumor microenvironment is negatively correlated with progression‐free survival in patients undergoing sorafenib treatment for HCC. Thus, gankyrin appears to play a critical oncogenic function in tumor microenvironment and may be a potential target for developing therapeutic and preventive strategies against HCC.

IFN‐γ plays an essential role in the pathogenesis of gastric lymphoid follicles formation caused by Helicobacter suis infection

In this study, we aimed to assess the role of helper T cells in the development of gastric lymphoid follicles induced by Helicobacter suis infection. C57BL/6J mice were orally inoculated with H. suis. Six weeks after infection, gastric lymphoid follicles were observed in the gastric mucosa by hematoxylin and eosin staining, and the number of follicles was increased throughout the infection period. An immunohistological examination showed that the lymphoid follicles were composed of B cells, CD4-positive helper T cells, and dendritic cells (DC). It was also revealed that the mRNA expression level of interferon-γ (IFN-γ) in the gastric mucosa was significantly increased at 12 weeks after infection. No gastric lymphoid follicles were detected in IFN-γ-deficient mice that had been infected with H. suis at 12 weeks after infection, although the development of lymphoid follicles in IL-4-deficient mice infected with H. suis was similar to that seen in the wild-type mice. In conclusion, IFN-γ, a Th1 cytokine, is deeply involved in the pathogenesis of gastric lymphoid follicles induced by H. suis infection, and it is suggested that CD4-positive T cells and DC aid in the expansion of gastric lymphoid follicles.

Chronic Fibro-Inflammatory Responses in Autoimmune Pancreatitis Depend on IFN-α and IL-33 Produced by Plasmacytoid Dendritic Cells

In previous studies, we found that human IgG4-related autoimmune pancreatitis (AIP) and murine AIP are driven by activation of plasmacytoid dendritic cells (pDCs) producing IFN-α. In the present studies we examined additional roles of pDC-related mechanisms in AIP pathogenesis, particularly those responsible for induction of fibrosis. We found that in murine AIP (MRL/Mp mice treated with polyinosinic-polycytidylic acid) not only the pancreatic infiltration of immune cells but also the development of fibrosis were markedly reduced by the depletion of pDCs or blockade of type I IFN signaling; moreover, such treatment was accompanied by a marked reduction of pancreatic expression of IL-33. Conversely, polyinosinic-polycytidylic acid–induced inflamed pancreatic tissue in murine AIP exhibited increased expression of type I IFNs and IL-33 (and downstream IL-33 cytokines such as IL-13 and TGF-β1). pDCs stimulated by type I IFN were the source of the IL-33 because purified populations of these cells isolated from the inflamed pancreas produced a large amount of IL-33 upon activation by TLR9 ligands, and such production was abrogated by the neutralization of type I IFN. The role of IL-33 in murine AIP pathogenesis was surprisingly important because blockade of IL-33 signaling by anti-ST2 Ab attenuated both pancreatic inflammation and accompanying fibrosis. Finally, whereas patients with both conventional pancreatitis and IgG4-related AIP exhibited increased numbers of acinar cells expressing IL-33, only the latter also exhibited pDCs producing this cytokine. These data thus suggest that pDCs producing IFN-α and IL-33 play a pivotal role in the chronic fibro-inflammatory responses underlying murine AIP and human IgG4-related AIP.

Complete response of a pancreatic adenosquamous carcinoma to chemoradiotherapy

A 51-year-old woman with an unresectable pancreatic tumor that was histologically diagnosed as an adenosquamous carcinoma underwent chemoradiotherapy with 5-fluourouracil (FU) and low-dose cisplatin (low-dose FP). Because we recognized a partial response to the chemoradiotherapy, we subsequently administered combined chemotherapy with S-1 and cisplatin. After one course of this combined chemotherapy, the tumor was further reduced in size and became difficult to discern on abdominal computed tomography (CT). We have continued to administer the S-1 and cisplatin combined chemotherapy, and the patient is still alive. After 20 months of treatment, the tumor has not recurred (as assessed by abdominal CT). Additionally, we have not seen elevation of tumor markers. This report presents the successful use of chemoradiotherapy with low-dose FP and additional combined chemotherapy with S-1 and cisplatin for unresectable pancreatic adenosquamous carcinoma.

Endoscopic ultrasonography‐guided choledochoduodenostomy using a newly designed laser‐cut metal stent: Feasibility study in a porcine model

Endoscopic ultrasonography (EUS)‐guided choledochoduodenostomy (EUS‐CDS) is increasingly used in the treatment of malignant distal biliary obstruction. Standardized use of this technique requires improvements in instruments, including more convenient and safer devices. The present study was designed to evaluate the resistance force to migration (RFM) of a newly designed laser‐cut metal stent and the feasibility of EUS‐CDS using this stent.

Multicenter prospective evaluation study of endoscopic ultrasound‐guided hepaticogastrostomy combined with antegrade stenting (with video)

Endoscopic ultrasonography‐guided hepaticogastrostomy (EUS‐HGS) is often indicated for advanced stage patients. Therefore it is important to prevent adverse events associated with EUS‐HGS procedures and obtain long stent patency. EUS‐guided antegrade stenting (AS) has been developed as an advanced technique. Thus, to prevent adverse events and achieve long stent patency, EUS‐AS combined with EUS‐HGS (EUS‐HGAS) has been reported. The aim of the present study was to evaluate the technical feasibility and efficacy of EUS‐HGAS in a multicenter, prospective study.

Smoking Status and the Incidence of Pancreatic Cancer Concomitant With Intraductal Papillary Mucinous Neoplasm.

Objectives The effect of smoking status on the incidence of pancreatic ductal adenocarcinoma (PDAC) concomitant with intraductal papillary mucinous neoplasm (IPMN) has not been clarified. This study investigated the association of smoking status with PDAC concomitant with IPMN. Methods The subjects were 124 consecutive patients undergoing resection of IPMNs (intraductal papillary mucinous adenoma (IPMA): N = 77, invasive IPMN: N = 31, and PDAC with IPMN: N = 16) between April 2008 and October 2015. The associations between smoking status (never/former/current smoker) or cumulative pack-years (0–19/20–39/≥40) and the incidence of PDAC concomitant with IPMN or invasive IPMN were evaluated. Results Current smoking, not former smoking, was associated with the incidence of PDAC concomitant with IPMN (PDAC with IPMN vs IPMN alone; P = 0.004, PDAC with IPMN vs IPMA; P = 0.004, PDAC with IPMN vs invasive IPMN; P = 0.04, respectively), but not that of invasive IPMN (invasive IPMN vs IPMA; P = 0.85). Cumulative pack-years were higher in patients who had PDAC concomitant with IPMN than in patients with invasive IPMN (P = 0.04). Cumulative pack-years were not associated with smoking status (current vs former). Conclusions Current smoking, not former smoking, was associated with the incidence of PDAC concomitant with IPMN. Cessation of smoking may be recommended for patients with IPMN.

Comparative Study of Clarithromycin- versus Metronidazole-Based Triple Therapy as First-Line Eradication for Helicobacter pylori

Introduction: Clarithromycin (CAM)-based triple therapy comprising proton pump inhibitors and amoxicillin is administered as first-line eradication treatment against Helicobacter pylori infection. However, the eradication rate achieved with CAM-based triple therapy has decreased to <80% owing to the emergence of CAM-resistant strains. This prospective randomized study aimed to compare the efficacy of CAM-based and metronidazole (MNZ)-based triple therapy in terms of H. pylori eradication. Methods:H. pylori-positive patients were treated with CAM-based triple therapy comprising esomeprazole and amoxicillin (EAC group) or with MNZ-based triple therapy comprising esomeprazole and amoxicillin (EAM group). Results:H. pylori eradication rates achieved in the intention-to-treat (ITT) and per protocol (PP) analyses were 70.6 and 72.7%, respectively, in the EAC group. Eradication rates obtained via ITT and PP analyses were 91.7 and 94.3%, respectively, in the EAM group. In the EAC group, eradication rates were significantly lower in patients harboring CAM-resistant strains than in those harboring CAM-sensitive strains. In contrast, eradication rates were comparable between patients harboring CAM-resistant strains and those harboring CAM-sensitive strains in the EAM group. Conclusion: MNZ-based triple therapy consisting of esomeprazole and amoxicillin is superior to CAM-based triple therapy containing esomeprazole and amoxicillin as first-line eradication treatment against H. pylori.