Background: Intestinal permeability and psychological stress are considered the key mechanism(s) in functional dyspepsia (FD). Although proton pump inhibitors (PPIs) are commonly used for the treatment of FD, the effect of PPIs on intestinal permeability has not been elucidated. This study investigated the effect of PPI on intestinal permeability under stressed conditions.Methods: C57BL/6J mice were subjected to water avoidance stress (WAS) and administered rabeprazole (40 mg/kg) or vehicle treatment (VT). We then evaluated intestinal permeability both in vivo and ex vivo using plasma fluorescein isothiocyanate‐dextran and by assessing the paracellular permeability and transepithelial electrical resistance (TEER) in an Ussing chamber, respectively. Furthermore, we evaluated the effect of PPI‐treated fecal microbiota transplant (FMT) on intestinal permeability in vivo. Microbiota profiles of donor feces were assessed by 16S rRNA gene analysis using MiSeq and QIIME2.Key Results: In the WAS treatment, PPI significantly enhanced intestinal permeability in vivo compared to that in VT. Moreover, PPI significantly increased paracellular permeability and decreased TEER in the duodenum and jejunum, respectively, compared to those in VT under stressed conditions. Moreover, both vasoactive intestinal peptide (VIP) receptor antagonist and ketotifen significantly reversed the effect of PPI on intestinal permeability. Furthermore, PPI‐treated FMT significantly increased the intestinal permeability in vivo compared to that in vehicle‐treated FMT. Proton pump inhibitors treatment altered the gut microbiota composition, indicating that PPI induced dysbiosis.Conclusions and Inferences: Under stressed conditions, PPI enhances intestinal permeability via dysbiosis of gut microbiota. Vasoactive intestinal peptide and mast cells are also implicated in the underlying mechanisms.

Summary: Background: Vonoprazan (V), a potassium‐competitive acid blocker, has a more durable acid‐inhibitory effect as compared with standard‐dose proton pump inhibitors (PPIs) but has not been compared with 2‐4 times higher daily PPI doses administered in two divided doses.Aims: To evaluate the acid‐inhibitory effect of V 10/20 mg once‐daily (OD; V10/V20) vs rabeprazole (R) 10/20 mg twice‐daily (BID; R20/R40) in healthy Japanese volunteers.Methods: This multicentre, randomised, open‐label, two‐period, crossover study compared V10 or V20 vs R20, or V20 vs R40 using three cohorts of 10 healthy Japanese adults. Within each cohort, subjects were randomised to receive V or R for 7 days and, following a washout period ≥7 days, the other treatment for 7 days. On day 6 of each period, 24‐hours multichannel gastric impedance‐pH monitoring was performed. Percent times pH ≥ 3, ≥4 and ≥5 (pH 3, 4 and 5 holding time ratios [HTRs]) in 24 hours were evaluated as primary pharmacodynamic endpoints.Results: Acid‐inhibitory effect (24‐hours pH 3 HTR) of V20 was greater than those of R20 (91.0% vs 65.3%; P = .0049) and R40 (98.5% vs 85.9%; P = .0073). Similar results were obtained for 24‐hours pH 4 and 5 HTRs. V20 also achieved greater nocturnal pH 4 (91.5% vs 73.2%; P = .0319) and 5 HTRs (78.8% vs 62.2%; P = .0325) as compared with R40. One subject (20%) developed diarrhoea while receiving R40 which was considered treatment‐related.Conclusions: Compared with 2‐4 times the standard daily dose of R, V20 exerts a more potent and durable acid‐inhibitory effect. Trial identifier: UMIN000022198 (www.umin.ac.jp/ctr/index.htm).

Patients with asymptomatic esophageal eosinophilia (aEE) do not exhibit clinical symptoms because of esophageal dysfunction, although they have endoscopic and histological findings similar to those of eosinophilic esophagitis (EoE). The cause of the symptoms and the differences between aEE and EoE are unclear. The aim of this study is to determine whether aEE and EoE are same disease entities by comparing immune-related tissue biomarkers using immunohistological staining. Esophageal biopsy specimens from 61 patients, including 18 with aEE and 43 with EoE, were analyzed. Immunofluorescence staining was performed to quantify the immune-related tissue biomarkers such as major basic protein, eosinophil-derived neurotoxin, eotaxin-3, and immunoglobulin G4. Data are presented as median (interquartile range). There were no significant differences in clinical, endoscopic, or histological features, between patients with aEE and EoE, with the exception of body mass index. There were no significant differences in all immune-related tissue biomarkers between both groups. In conclusions, EoE and aEE displayed similar immunohistological profiles. Hence, they may be similar disease entities with some common pathogenic mechanisms. Our findings suggest that patients with aEE also have histopathological esophageal inflammation.

Although tacrolimus is useful as an induction therapy in patients with ulcerative colitis (UC), information regarding the long-term outcome after tacrolimus therapy is insufficient. The aim of this study was to evaluate the clinical significance of the pretreatment neutrophil-to-lymphocyte ratio (NLR) as a prognostic factor in patients with UC receiving tacrolimus, to aid treatment selection. Patients with moderate-to-severe active UC who received oral tacrolimus induction therapy and subsequent immunomodulatory maintenance therapy at our hospital between 2009 and 2017 and who showed clinical response at week 12, were retrospectively enrolled. Cox regression analysis was conducted to study the prognostic role of the pretreatment NLR. The combined impact of the NLR and other known prognostic factors was investigated with multivariate regression. Among 45 patients included in this study, 21 patients experienced relapse during a median follow-up period of 16.6 months. Multivariate Cox regression analysis identified the pretreatment NLR (hazard ratio [HR]: 0.82, 95% confidence interval [CI]: 0.72–0.94, P < 0.01) and the use of immunomodulators at the start of tacrolimus treatment (HR: 0.18, 95% CI: 0.05–0.66, P = 0.01) as independent predictors of clinical relapse. The pretreatment NLR is an independent prognostic factor in patients with UC treated with tacrolimus.