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Background: Functional dyspepsia (FD) is associated with poor health-related quality of life. Recent evidence suggests that the main pathogenesis suspect is the gut mucosa-associated microbiota (MAM). However, little is known about the MAM in FD subjects. The aim of this study was to clarify the relationship between upper gastrointestinal symptoms in FD and the characteristics of the gastrointestinal MAM. Summary: Five mucosa samples from the upper gut (intraoral, mid-esophagus, gastric body, gastric antrum, and descending portion of the duodenum) were collected with a brush under endoscopic examination from FD and healthy control subjects. MAM profiles of each sample were analyzed by 16S-rRNA ­V3-V4 gene sequences. Questionnaire was used to assess gastrointestinal symptoms in FD. Between FD and healthy control subjects, although the comparison of MAM α-diversity showed no significant differences, the structure of MAM (β-diversity) was clearly different. Only the phylum Firmicutes was increased in FD compared to healthy control subjects in all sites of the upper gut. At the genus level, Streptococcus was significantly increased in all sites in the upper gut in FD. The relative abundance of Streptococcus was positively correlated with upper gastrointestinal symptoms in each upper gut group. Furthermore, the relative abundance of OTU 90 was positively correlated with upper gastrointestinal symptoms in all sites in the upper gut in FD. Key Messages: Streptococcus is a bacterium strongly correlated with upper gastrointestinal symptoms in FD.

Functional dyspepsia (FD) is associated with poor health-related quality of life. Recent evidence suggests that the main pathogenesis suspect is the gut mucosa-associated microbiota (MAM). However, little is known about the MAM in FD subjects. The aim of this study was to clarify the relationship between upper gastrointestinal symptoms in FD and the characteristics of the gastrointestinal MAM.Five mucosa samples from the upper gut (intraoral, mid-esophagus, gastric body, gastric antrum, and descending portion of the duodenum) were collected with a brush under endoscopic examination from FD and healthy control subjects. MAM profiles of each sample were analyzed by 16S-rRNA -V3-V4 gene sequences. Questionnaire was used to assess gastrointestinal symptoms in FD. Between FD and healthy control subjects, although the comparison of MAM α-diversity showed no significant differences, the structure of MAM (β-diversity) was clearly different. Only the phylum Firmicutes was increased in FD compared to healthy control subjects in all sites of the upper gut. At the genus level, Streptococcus was significantly increased in all sites in the upper gut in FD. The relative abundance of Streptococcus was positively correlated with upper gastrointestinal symptoms in each upper gut group. Furthermore, the relative abundance of OTU 90 was positively correlated with upper gastrointestinal symptoms in all sites in the upper gut in FD. Key Messages: Streptococcus is a bacterium strongly correlated with upper gastrointestinal symptoms in FD.

Background: The importance of microbiota infiltrating the gut mucus layer has been reported in the pathogenesis of various gastrointestinal and systemic diseases. However, little is known about the mucosa-associated microbiota (MAM) in healthy subjects. The present study aimed to clarify the characteristics of the gastrointestinal MAM from the oral cavity to the rectum in healthy Japanese subjects. Methods: Seventeen healthy subjects were enrolled. In this study, 5 mucosa samples from the upper gut (intraoral, mid-esophagus, gastric corpus, gastric antrum, and duodenum) and 7 from the lower gut (ileum, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum) were collected with a brush under endoscopic examination. MAM profiles of each sample were analyzed by 16S-rRNA V3-V4 gene sequences. Results: Collecting mucosa samples by brushing provided sufficient material for MAM profiling without causing adverse effects. The upper and lower gut MAM profiles differed significantly (p < 0.0001). In the upper and lower gut, the intra- and inter-individual MAM profiles were significantly different (p = 0.0008 and p < 0.0001 respectively). Conclusions: The MAM profiles of the upper and lower gut were significantly different. The inter-individual differences in MAM were remarkable compared to the intra-individual differences.

Background: Irritable bowel syndrome (IBS) causes chronic abdominal pain and abnormal bowel movements. The etiology involves complicated interactions among visceral hypersensitivity, disorders related to bowel movements, and stress. Changes in the microbiota affect the IBS pathophysiology. We investigated changes in colorectal motility, structure, and microbiota in response to stress due to maternal separation (MS) and corticotropin-releasing hormone (CRH) administration in rats. Summary: Neonatal rats were separated from their mothers for 3 h daily from postnatal day (PND) 2 to PND14. The control group included rats of the same age that were not separated. After MS, the rats were undisturbed for 5 weeks. At 8 weeks of age, 10 µg of CRH or saline was intravenously administered to MS and control groups. Two hours later, the number of fecal pellets was counted. Three hours after CRH or saline administration, the rats were sacrificed and colorectal tissue samples and cecal contents were collected to analyze the fecal microbiota. The number of fecal pellets was significantly greater in MS with the CRH group. Both stressors altered the microbiota composition. Key Messages: Among rats that received CRH, MS increased the colorectal motility. Stress due to MS altered the gut microbiota composition.

Early-stage gastric cancer (EGC) is detected even after successful Helicobacter pylori eradication. This study is aimed at clarifying the clinicopathological characteristics of EGC detected after successful H. pylori eradication.This retrospective study analyzed 57 cases of EGC detected after successful H. pylori eradication and resected endoscopically at Kyoto Prefectural University of Medicine, between January 2009 and June 2014. Clinicopathological findings of 57 cases (H. pylori-eradicated group) were investigated, and compared with those in active H. pylori infection resected in the same period (H. pylori-positive group).Most EGCs were detected in patients with severe atrophic mucosa, both in H. pylori-eradicated and H. pylori-positive groups, while the percentage of EGC detected in patients with mild atrophic mucosa gradually increased over time from successful eradication (H. pylori-positive: 7%, up to the fourth year since eradication: 11%, after the fifth year since eradication: 32%). The percentage of EGC detected in patients with mild atrophic mucosa after the fifth year since eradication was significantly higher than that in patients with active H. pylori infection (p = 0.004).After the fifth year following eradication, we should be alert to the incidence of EGC, irrespective of the severity of mucosal atrophic change.

Background/Aim: Recently, it has been shown that serine proteases derived from microorganisms stimulate epithelial cells to produce inflammatory mediators through protease-activated receptor (PAR). We investigated the involvement of PAR2 in the interleukin (IL)-8 production by Helicobacter pylori-infected gastric epithelial cells. Methods and Results: Human gastric epithelial cells, MKN45 cells, were used. The expression of PAR2 was assessed by real-time PCR and immunocytochemistry, and IL-8 protein was measured by an enzyme-linked immunosorbent assay. PAR2 mRNA and protein were constitutively expressed on unstimulated MKN45 cells. The treatment of cells with H. pylori resulted in a significant increase in PAR2 expression. In addition, trypsin (a natural PAR2 agonist), SLIGKV amide (a synthetic PAR2 agonist), H. pylori live bacteria or H. pylori culture supernatant significantly induced IL-8 production from MKN45 cells. H. pylori-induced IL-8 production was inhibited by nafamostat mesilate (a serine protease inhibitor), neutralizing antibody to PAR2 and in PAR2-deficient cells treated with siRNA. Conclusions: These results reveal that H. pylori-derived protease activates gastric epithelial cells to produce inflammatory cytokines through PAR2, suggesting an important role for PAR2 in the modulation of gastric inflammation associated with H. pylori.

Background/Aims: Acute-phase intestinal ischemia-reperfusion (I-R) injury can result in multiple organ failure, which may sometimes be fatal. However, no reliable treatment for this clinical state is available. Rapamycin has been reported to protect heart, brain and kidney against I-R injury. The aim of this study was to examine whether rapamycin could protect mice against I-R-induced intestinal and remote organ injury. Methods: Ischemia was induced in the intestine of C57BL/6 mice by occluding the superior mesenteric artery for 1 h. Mice received rapamycin at a dose of 5 mg/kg or vehicle by the intraperitoneal injection 1 h before ischemia. The survival rate, inflammatory responses in the intestine and the lung, bacteria cultured from lung tissue and the phagocytic capacity of alveolar macrophages were examined. Results: Treatment with rapamycin improved survival rate after intestinal I-R. Histological and biochemical parameters of I-R-induced intestinal injury/inflammation were similar in both rapamycin-treated and untreated mice. However, signs of lung injury/inflammation were significantly attenuated in rapamycin-treated mice compared to control mice. The reduction of lung bacteria and the increase in phagocytic activity were accompanied in mice treated with rapamycin. Conclusion: Rapamycin improved mortality following intestinal I-R via the inhibition of remote lung inflammation in mice.

Previous investigations have demonstrated that the cellular signaling induced by hypoxia-reoxygenation is a major pathway contributing to gastric mucosal injury induced by stress, non-steroidal anti-inflammatory drugs, and Helicobacter pylori. The aim of the present study was to perform a gene expression analysis of the gastric mucosal cellular response and to define the protective molecules in hypoxia and reoxygenation using a high-density DNA microarray analysis. Normal rat gastric mucosal (RGM-1) cells were subjected to hypoxia for 2 h, and reoxygenation was initiated by placing the cells in an environment of normoxia for 2, 4, or 8 h. Total RNA was extracted, and differences in the gene expression profiles between the normoxia and hypoxia groups or among the different durations of reoxygenation were investigated using a high-density DNA microarray. HIF-1- and apoptosis-related genes were modulated by hypoxia. Moreover, inflammation-, stress-, and wound- healing-related genes were regulated by reoxygenation following hypoxia. In particular, the expression of heat shock protein-70, amphiregulin and cyclooxygenase-2 were upregulated during reoxygenation following hypoxia, suggesting that these upregulations may play an important role in maintaining cell survival and supporting cell function.

Recently, it has been shown that serine proteases derived from microorganisms stimulate epithelial cells to produce inflammatory mediators through protease-activated receptor (PAR). We investigated the involvement of PAR2 in the interleukin (IL)-8 production by Helicobacter pylori-infected gastric epithelial cells.Human gastric epithelial cells, MKN45 cells, were used. The expression of PAR2 was assessed by real-time PCR and immunocytochemistry, and IL-8 protein was measured by an enzyme-linked immunosorbent assay. PAR2 mRNA and protein were constitutively expressed on unstimulated MKN45 cells. The treatment of cells with H. pylori resulted in a significant increase in PAR2 expression. In addition, trypsin (a natural PAR2 agonist), SLIGKV amide (a synthetic PAR2 agonist), H. pylori live bacteria or H. pylori culture supernatant significantly induced IL-8 production from MKN45 cells. H. pylori-induced IL-8 production was inhibited by nafamostat mesilate (a serine protease inhibitor), neutralizing antibody to PAR2 and in PAR2-deficient cells treated with siRNA.These results reveal that H. pylori-derived protease activates gastric epithelial cells to produce inflammatory cytokines through PAR2, suggesting an important role for PAR2 in the modulation of gastric inflammation associated with H. pylori.