Published papers

© 2019 Kondo et al. Background The number of patients with Crohn's disease (CD) in Japan has recently been increasing. We examined the association between environmental factors and the development of CD in Japanese focusing on passive smoking. Methods We conducted a multicenter case-control study and compared the environmental factors of 93 cases who were newly diagnosed with CD to the environmental factors of 132 controls (hospital-, age-, and sex-matched patients with other diseases). The odds ratio (OR) of each factor for the development of CD and the 95% confidence interval (CI) were calculated using a logistic regression model. The association between the details of passive smoking history and the development of CD was examined for those who had an active smoking history "no". Odds ratios of number of passively smoked cigarettes (per day), time of passive smoking (per day) and period of passive smoking (year) were calculated using "passive smoking 'No'" as a reference. Results History of appendicitis, family history of inflammatory bowel disease, and active smoking history were not significantly associated with the development of CD. Drinking history showed a decreased OR for the development of CD (0.39, 0.19-0.77). "Passive smoking Yes" showed significantly increased OR (2.49, 1.09-5.73). Regarding the association between passive smoking and the development of CD, the OR increased as the number of cigarettes per day, smoking time per day, and smoking duration increased, and there was a dose-response relationship (trend P = 0.024, 0.032, 0.038). Conclusions The association between environmental factors and the development of CD among Japanese was examined by case-control study. It was suggested that the passive smoking history may be associated to the development of CD.

© 2019 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd Objective: To identify risk factors of imaging progression (increase in cyst size or main pancreatic duct size, or a new mural nodule) in low-risk branch duct intraductal papillary mucinous neoplasm (BD-IPMN), including obesity-related factors such as pancreatic fat content. Methods: Our hospital databases were searched for patients who had completed health checkup, including upper abdominal magnetic resonance imaging (MRI) over 48 months (August 2012 to July 2016). Individuals with BD-IPMN without worrisome features and high-risk stigmata who underwent surveillance with at least one follow-up MRI, irrespective of the follow-up period, were included. Pancreatic computed tomography attenuation indexes were defined as the difference between the pancreas and spleen attenuation (P - S) and the pancreas to spleen attenuation ratio (P/S). Results: Among 75 patients diagnosed as having low-risk BD-IPMN, during a median follow-up of 36 months, 11 (15%) had imaging progression in cyst size, including two with worrisome features. A multivariate logistic analysis showed that the initial cyst size and both indexes (P - S, or P/S) were significantly associated with imaging progression in IPMN, respectively (Model 1: odds ratio [OR] 1.188, 95% confidence interval [CI] 1.060-1.331, P = 0.003; OR 0.871, 95% CI 0.776-0.977, P = 0.019; Model 2: OR 1.186, 95% CI 1.064-1.322, P = 0.002; OR 0.002, 95% CI 0.000-0.970, P = 0.049). Conclusions: Pancreatic fat content and initial cyst size were significantly associated with imaging progression in low-risk BD-IPMN. Revisions of international consensus Fukuoka guidelines might be customized based on initial cyst size and pancreatic fat content.

© 2019, American Society for Clinical Investigation. Acute liver failure (ALF) is a life-threatening condition, and liver transplantation is the only therapeutic option. Although immune dysregulation is central to its pathogenesis, the precise mechanism remains unclear. Here, we show that the number of peripheral and hepatic plasmacytoid DCs (pDCs) decrease during acute liver injury in both humans and mice. Selective depletion of pDCs in Siglechdtr/+ mice exacerbated concanavalin A–induced acute liver injury. In contrast, adoptively transferred BM-derived pDCs preferentially accumulated in the inflamed liver and protected against liver injury. This protective effect was independent of TLR7 and TLR9 signaling, since a similar effect occurred following transfer of MyD88-deficient pDCs. Alternatively, we found an unexpected immunosuppressive role of pDCs in an IL-35–dependent manner. Both Il12a and Ebi3, heterodimeric components of IL-35, were highly expressed in transferred pDCs and CD4+CD25+ Tregs. However, the protective effect of pDC transfer was completely lost in mice depleted of Tregs by anti-CD25 antibody. Moreover, pDCs derived from IL-35–deficient mice had less of a protective effect both in vivo and in vitro even in the presence of Tregs. These results highlight a unique aspect of pDCs in association with Tregs, serving as a guide for immunotherapeutic options in ALF.

© 2019 European Association for the Study of the Liver Background & Aims: The effect of hepatocellular carcinoma (HCC) on the response to interferon-free direct-acting antiviral (DAA) therapy in patients with chronic hepatitis C (CHC) infection remains unclear. Using a systematic review and meta-analysis approach, we aimed to investigate the effect of DAA therapy on sustained virologic response (SVR) among patients with CHC and either active, inactive or no HCC. Methods: PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched from 1/1/2013 to 9/24/2018. The pooled SVR rates were computed using DerSimonian-Laird random-effects models. Results: We included 49 studies from 15 countries, comprised of 3,341 patients with HCC and 35,701 without HCC. Overall, the pooled SVR was lower in patients with HCC than in those without HCC (89.6%, 95% CI 86.8–92.1%, I2 = 79.1% vs. 93.3%, 95% CI 91.9–94.7%, I2 = 95.0%, p = 0.0012), translating to a 4.8% (95% CI 0.2–7.4%) SVR reduction by meta-regression analysis. The largest SVR reduction (18.8%) occurred in patients with active/residual HCC vs. inactive/ablated HCC (SVR 73.1% vs. 92.6%, p = 0.002). Meanwhile, patients with HCC who received a prior liver transplant had higher SVR rates than those who did not (p <0.001). Regarding specific DAA regimens, patients with HCC treated with ledipasvir/sofosbuvir had lower SVR rates than patients without HCC (92.6%, n = 884 vs. 97.8%, n = 13,141, p = 0.026), but heterogeneity was high (I2 = 84.7%, p <0.001). The SVR rate was similar in patients with/without HCC who were treated with ombitasvir/paritaprevir/ritonavir ± dasabuvir (n = 101) (97.2% vs. 94.8%, p = 0.79), or daclatasvir/asunaprevir (91.7% vs. 89.8%, p = 0.66). Conclusion: Overall, SVR rates were lower in patients with HCC, especially with active HCC, compared to those without HCC, though heterogeneity was high. Continued efforts are needed to aggressively screen, diagnose, and treat HCC to ensure higher CHC cure rates. Lay summary: There are now medications (direct-acting antivirals or “DAAs”) that can “cure” hepatitis C virus, but patients with hepatitis C and liver cancer may be less likely to achieve cure than those without liver cancer. However, patients with liver cancer are also more likely to have advanced liver disease and risk factors that can decrease cure rates, so better controlled studies are needed to confirm these findings.

© 2019, The Society for Surgery of the Alimentary Tract. Background: Infected acute necrotic collections (ANC) and walled-off necrosis (WON) of the pancreas are associated with high mortality. The difference in mortality between open necrosectomy and minimally invasive therapies in these patients remains unclear. Methods: This retrospective multicenter cohort study was conducted among 44 institutions in Japan from 2009 to 2013. Patients who had undergone invasive treatment for suspected infected ANC/WON were enrolled and classified into open necrosectomy and minimally invasive treatment (laparoscopic, percutaneous, and endoscopic) groups. The association of each treatment with mortality was evaluated and compared. Results: Of 1159 patients with severe acute pancreatitis, 122 with suspected infected ANC or WON underwent the following treatments: open necrosectomy (33) and minimally invasive treatment (89), (laparoscopic three, percutaneous 49, endoscopic 37). Although the open necrosectomy group had a significantly higher mortality on univariate analysis (p = 0.047), multivariate analysis showed no significant associations between open necrosectomy or Charlson index and mortality (p = 0.29, p = 0.19, respectively). However, age (for each additional 10 years, p = 0.012, odds ratio [OR] 1.50, 95% confidence interval [CI] 1.09–2.06) and revised Atlanta criteria-severe (p = 0.001, OR 7.84, 95% CI 2.40–25.6) were significantly associated with mortality. Conclusions: In patients with acute pancreatitis and infected ANC/WON, age and revised Atlanta criteria-severe classification are significantly associated with mortality whereas open necrosectomy is not. The mortality risk for patients undergoing open necrosectomy and minimally invasive treatment does not differ significantly. Although minimally invasive surgery is generally preferred for patients with infected ANC/WON, open necrosectomy may be considered if clinically indicated.

Objective: Crohn's disease (CD) is a chronic inflammatory gastrointestinal disease with repeated cycles of exacerbation and remission. Infliximab (IFX), a chimeric anti-TNF-α monoclonal antibody, has been widely used for the treatment of CD. However, no study in Japanese CD patients receiving continuous IFX for more than 1 year has been reported. To avoid therapeutic failure during long-term administration in Japanese CD patients, we evaluated the variable factors of IFX pharmacokinetics and the optimal trough IFX concentration at 8 weeks after administration. Materials and methods: Population pharmacokinetic (PPK) analysis was performed using the nonlinear mixed-effect model based on the IFX serum concentration in 832 samples from 121 patients. A one-compartment model was used to examine interindividual variability in the systemic clearance (CL) of intravenously administered IFX. Results: PPK estimates (estimated value, RSE%) were total clearance (CL: 0.018 L/h, 9.1) and volumes of distribution (Vd: 7.35 L, 12.0). Interindividual variability for CL and Vd of 0.11 and 0.16, respectively, was found. Body weight, antibody to IFX (ATI), and albumin level were factors affecting the IFX CL. IFX CL was greater in the ATI-positive than in the ATInegative group. CL was also greater in nonremission patients. There was a significant association between the predicted serum IFX trough concentration at 8 weeks and therapeutic response with long-term continuous administration (p < 0.05), with a higher concentration at 8 weeks seen in the remission group. Conclusion: Using these variables including body weight, ATI, and albumin level, the IFX dose could be calculated for individual CD patients to achieve the optimal therapeutic range.

Biliary tract cancer (BTC) arises from biliary epithelial cells (BECs) and includes intrahepatic cholangiocarcinoma (IHCC), gallbladder cancer (GC), and extrahepatic cholangiocarcinoma (EHCC). Although frequent KRAS mutations and epigenetic changes at the INK4A/ARF locus have been identified, the molecular pathogenesis of BTC is unclear and the development of corresponding anticancer agents remains inadequate. We isolated epithelial cell adhesion molecule (EpCAM)–positive BECs from the mouse intrahepatic bile duct, gallbladder, and extrahepatic bile duct, and established organoids derived from these cells. Introduction of activated KRAS and homozygous deletion of Ink4a/Arf in the cells of each organoid type conferred the ability to form lethal metastatic adenocarcinoma with differentiated components and a pronounced desmoplastic reaction on cell transplantation into syngeneic mice, indicating that the manipulated cells correspond to BTC–initiating cells. The syngeneic mouse models recapitulate the pathological features of human IHCC, GC, and EHCC, and they should therefore prove useful for the investigation of BTC carcinogenesis and the development of new therapeutic strategies. Tumor cells isolated from primary tumors formed organoids in three-dimensional culture, and serial syngeneic transplantation of these cells revealed that their cancer stem cell properties were supported by organoid culture, but not by adherent culture. Adherent culture thus attenuated tumorigenic activity as well as the expression of both epithelial and stem cell markers, whereas the expression of epithelial-mesenchymal transition (EMT)–related transcription factor genes and mesenchymal cell markers was induced. Our data show that organoid culture is important for maintenance of epithelial cell characteristics, stemness, and tumorigenic activity of BTC–initiating cells.

Background and Aim: E6011 is a humanized monoclonal antibody targeting fractalkine (FKN), a CX3C chemokine, which regulates leukocyte trafficking during inflammation. We evaluated the safety and pharmacokinetic profile of E6011 in patients with Crohn's disease (CD) and also performed preliminary pharmacodynamic (PD) and efficacy assessments. Methods: This study included a 12-week multiple ascending dose (MAD) phase (2, 5, 10, and 15 mg/kg intravenously every 2 weeks, n = 6, 8, 7, and 7, respectively) and a 40-week Extension phase (n = 12) at the same dose as the MAD phase. Serum E6011, serum total FKN (free soluble FKN and E6011-FKN complex) as a PD marker and CD activity index were evaluated. The primary outcome was safety assessment in the MAD phase. Results: Twenty-seven (96%) of 28 patients had previously been treated with anti-tumor necrosis factor α agents. During the MAD phase, adverse events (AEs) occurred in 18 (64%). The most common AE was nasopharyngitis (five patients, 18%). No severe AEs occurred. Serious AEs occurred in three patients, progression of CD in two, and anemia in one. Serum E6011 concentrations increased dose-dependently after infusion and reached a plateau around 4–6 weeks. Serum total FKN rose simultaneously. Five (18%) patients developed anti-E6011 antibodies during the study. Overall, clinical response and clinical remission were observed at Week 12 in 40% (10/25) and 16% (4/25) of active CD patients, respectively. Conclusion: E6011 was well-tolerated and might be effective in CD patients. These findings need to be clarified in a randomized controlled study.

The MHC class I-like molecule CD1d is a nonpolymorphic antigen-presenting glycoprotein, and its ligands include glycolipids, such as α-GalCer. The complexes between CD1d and ligands activate natural killer T cells by T cell receptor recognition, leading to the secretion of various cytokines (IFN-γ, IL-4, IL-17A, etc.). Herein, we report structure–activity relationship studies of α-GalCer derivatives containing various functional groups in their lipid acyl chains. Several derivatives have been identified as potent CD1d ligands displaying higher cytokine induction levels and/or unique cytokine polarization. The studies also indicated that flexibility of the lipid moiety can affect the binding affinity, the total cytokine production level and/or cytokine biasing. Based on our immunological evaluation and investigation of physicochemical properties, we chose bisamide- and Bz amide-containing derivatives 2 and 3, and evaluated their in vivo efficacy in a DSS-induced model of ulcerative colitis. The derivative 3 that exhibits Th2- and Th17-biasing responses, demonstrated significant protective effects against intestinal inflammation in the DSS-induced model, after a single intraperitoneal injection.

Individuals with chronic atrophic gastritis who are negative for active H. pylori infection with no history of eradication therapy have been identified in clinical practice. By excluding false-negative and autoimmune gastritis cases, it can be surmised that most of these patients have experienced unintentional eradication of H. pylori after antibiotic treatment for other infectious disease, unreported successful eradication, or H. pylori that spontaneously disappeared. These patients are considered to have previous H. pylori infection–induced atrophic gastritis. In this work, we define these cases based on the following criteria: absence of previous H. pylori eradication; atrophic changes on endoscopy or histologic confirmation of glandular atrophy; negative for a current H. pylori infection diagnosed in the absence of proton-pump inhibitors or antibiotics; and absence of localized corpus atrophy, positivity for autoantibodies, or characteristic histologic findings suggestive of autoimmune gastritis. The risk of developing gastric cancer depends on the atrophic grade. The reported rate of developing gastric cancer is 0.31%-0.62% per year for successfully eradicated severely atrophic cases (pathophysiologically equal to unintentionally eradicated cases and unreported eradicated cases), and 0.53%-0.87% per year for spontaneously resolved cases due to severe atrophy. Therefore, for previous H. pylori infection–induced atrophic gastritis cases, we recommend endoscopic surveillance every 3 years for high-risk patients, including those with endoscopically severe atrophy or intestinal metaplasia. Because of the difficulty involved in the endoscopic diagnosis of gastric cancer in cases of previous infection, appropriate monitoring of the high-risk subgroup of this understudied population is especially important.

The nuclear receptor peroxisome proliferator-activated receptor (PPAR)γ has been implicated in the pathogenesis of various human diseases including fatty liver. Although nuclear translocation of PPARγ plays an important role in PPARγ signaling, details of the translocation mechanisms have not been elucidated. Here we demonstrate that PPARγ2 translocates to the nucleus and activates signal transduction through H2O2-dependent formation of a PPARγ2 and transportin (Tnpo)1 complex via redox-sensitive disulfide bonds between cysteine (Cys)176 and Cys180 of the former and Cys512 of the latter. Using hepatocyte cultures and mouse models, we show that cytosolic H2O2/Tnpo1-dependent nuclear translocation enhances the amount of DNA-bound PPARγ and downstream signaling, leading to triglyceride accumulation in hepatocytes and liver. These findings expand our understanding of the mechanism underlying the nuclear translocation of PPARγ, and suggest that the PPARγ and Tnpo1 complex and surrounding redox environment are potential therapeutic targets in the treatment of PPARγ-related diseases.

Background & Aims: The number of patients with non-alcoholic steatohepatitis (NASH) is increasing globally. Recently, specific chemokine receptors have garnered interest as therapeutic targets in NASH. This is the first report to examine the role of the C-C chemokine receptor 9 (CCR9)/C-C chemokine receptor ligand 25 (CCL25) axis, and to reveal its therapeutic potential in NASH. Methods: Patients with biopsy-proven non-alcoholic liver disease (NAFLD) were recruited and their serum and hepatic chemokine expression was examined. Furthermore, wild-type (WT) and Ccr9−/− mice were fed a high-fat high-cholesterol (HFHC) diet for 24 weeks to establish NASH. Results: Serum CCL25, and hepatic CCR9 and CCL25 expression levels were increased in patients with NASH compared to healthy volunteers. Furthermore, Ccr9−/− mice were protected from HFHC diet-induced NASH progression both serologically and histologically. Flow cytometry and immunohistochemistry analysis showed that CCR9+CD11b+ inflammatory macrophages accumulated in the inflamed livers of HFHC diet-fed mice, while the number was reduced in Ccr9−/− mice. Consistent with human NASH livers, CCR9 was also expressed on hepatic stellate cells (HSCs) in mice with NASH, while CCR9-deficient HSCs showed less fibrogenic potential in vitro. Administration of a CCR9 antagonist hampered further fibrosis progression in mice with NASH, supporting its potential clinical application. Finally, we showed that CCR9 blockade attenuated the development of NAFLD-related hepatocellular carcinoma in HF diet-fed mice injected with diethylnitrosamine. Conclusions: These results highlight the role of the CCR9/CCL25 axis on macrophage recruitment and fibrosis formation in a murine NASH model, providing new insights into therapeutic strategies for NASH. Lay summary: Herein, we show that a specific chemokine axis involving a receptor (CCR9) and its ligand (CCL25) contributes to the progression of non-alcoholic steatohepatitis and carcinogenesis in humans and mice. Furthermore, treatment with a CCR9 antagonist ameliorates the development of steatohepatitis and holds promise for the treatment of patients with non-alcoholic steatohepatitis.

Background & Aims: We compared the diagnostic accuracy of the fecal calprotectin (FCP) test vs the fecal immunochemical blood test (FIT) in determining the endoscopic severity and predicting outcomes of patients with ulcerative colitis (UC). Methods: We performed a nationwide study of 879 patients with UC, enrolled at medical centers across Japan, from March 2015 to March 2017. We collected data on fecal biomarkers, endoscopic severities, and other clinical indices from Cohort 1 (n = 427) and assessed the diagnostic accuracy of FCP measurement and FIT results in determining clinical severity, based on Mayo score, and endoscopic remission, based on Mayo endoscopic sub-score (MES) or UC endoscopic index of severity. We also followed 452 patients in clinical remission from UC (Cohort 2) for 12 months and evaluated the associations of FCP levels and FIT results with clinical recurrence. Results: The levels of FCP and FIT each correlated with the MES and UC endoscopic index of severity. There were no significant differences in the areas under the curve of FCP vs FIT in distinguishing patients with MES≤1 from those with MES≥2 (P = .394) or in distinguishing patients with MES=0 from those with MES≥1 (P = .178). Among 405 patients in clinical remission at baseline, 38 (9.4%) had UC recurrences within 3 months and 90 (22.2%) had recurrences within 12 months. FCP≥146 mg/kg (hazard ratio [HR], 4.83; 95% confidence interval [CI], 2.80-8.33) and FIT≥77 ng/mL (HR, 2.92; 95% CI, 1.76-4.83) were independently associated with clinical recurrence within 12 months. UC recurred within 12 months in 69% of patients with levels of FCP≥146 mg/kg and FIT ≥77 ng/mL; this value was significantly higher than the rate of recurrence in patients with levels of FCP≥146 mg/kg and FIT <77 ng/mL (31.5%, P < .001) or patients with levels of FCP<146 mg/kg and FIT ≥77 ng/mL (30.0%, P < .001). Conclusion: In a nationwide study of patients with UC in Japan, we found that the level of FCP and FIT could each identify patients with endoscopic markers of disease severity (MES≥2). The combination of FCP and FIT results can identify patients in remission who are at risk for disease recurrence. Clinical Trials Registry no: UMIN000017650 (http://www.umin.ac.jp/ctr/)

Background: Small bowel lesions of Crohn’s disease (CD) are known to be associated with a poor prognosis; however, endoscopic healing leads to favorable patients’ outcome. The aim of this study was to clarify the clinical impact of assessing deep small bowel lesions (DSB) using balloon-assisted enteroscopy (BAE) on CD patients in clinical remission. Methods: From January 2012 to July 2018, a total of 100 CD patients in clinical remission were enrolled to undergo trans-anal enteroscopy using single-balloon enteroscope. Endoscopic evaluations at the terminal ileum (TI) were performed using a partial Simple Endoscopic Score for CD (pSES-CD). Endoscopic evaluations at the DSB used a modified partial SES-CD (mpSES-CD). We evaluated the factors associated with relapse, and the correlation of endoscopic score between the TI and DSB. For this study, relapse was defined as hospitalization within a year from enteroscopy. Results: 30 patients (30.0%) relapsed within a year from enteroscopy. Multivariate logistic regression analysis revealed that the Harvey–Bradshaw Index (OR 1.77, 95% CI 1.18–2.65; p = 0.003) and an mpSES-CD at DSB (OR 3.10, 95% CI 1.86–5.15; p = 0.001) were independent predictors for relapse, whereas a SES-CD at the TI did not exhibit independence. There was a significant correlation trend between the relapse rate and greater than 5 points of an mpSES-CD at DSB; however, there was no correlation between the relapse rate and pSES-CD at the TI. Conclusion: Even when Crohn's disease is in remission, it is important to evaluate DSB using BAE to assess endoscopic mucosal healing.

Background and Aim. Direct oral anticoagulant- (DOAC-) induced small-bowel lesions have not been described. We evaluated small-bowel lesions related to DOAC using video capsule endoscopy (VCE). Methods. This study was a prospective, open-label, nonblinded, multicenter, and observational study. From September 2013 to March 2017, patients taking DOACs were enrolled. Patients underwent VCE. The type and location of small-bowel lesions were registered. Also, (1) the proportion of lesions detected between types of DOAC was evaluated and (2) the hemoglobin (Hb) and serum ferritin levels were compared between patients with and without small-bowel lesions. Results. 33 patients were enrolled, but 4 patients withdrew their consent, and VCE was performed on 29 patients. Eight, 13, and 8 patients received dabigatran, rivaroxaban, and apixaban, respectively. Small-bowel transit was complete in 27 of 29 patients (93.1%). Small-bowel lesions were detected in 23 (79.3%), redness in 12 (41.4%), erosions in 14 (48.3%), and angioectasia in 3 (10.3%) patients, and 6 patients (20.7%) had no abnormalities. Redness and erosions were detected in the upper, middle, or lower portions, but erosions tended to be less frequent in the middle portion (p=0.25, 0.06). Angioectasia was not detected in the lower portion. No patients had active bleeding. The findings did not differ according to the drug. The relationships between the endoscopic findings and the Hb and serum ferritin levels were not significant. Conclusion. Many patients taking DOACs had small-bowel lesions; however, most lesions were relatively mild. Observing small-bowel lesions over longer periods may be necessary in patients taking DOACs. This trial is registered with UMIN000011527.

With ageing, normal human tissues experience an expansion of somatic clones that carry cancer mutations1–7. However, whether such clonal expansion exists in the non-neoplastic intestine remains unknown. Here, using whole-exome sequencing data from 76 clonal human colon organoids, we identify a unique pattern of somatic mutagenesis in the inflamed epithelium of patients with ulcerative colitis. The affected epithelium accumulates somatic mutations in multiple genes that are related to IL-17 signalling—including NFKBIZ, ZC3H12A and PIGR, which are genes that are rarely affected in colon cancer. Targeted sequencing validates the pervasive spread of mutations that are related to IL-17 signalling. Unbiased CRISPR-based knockout screening in colon organoids reveals that the mutations confer resistance to the pro-apoptotic response that is induced by IL-17A. Some of these genetic mutations are known to exacerbate experimental colitis in mice8–11, and somatic mutagenesis in human colon epithelium may be causally linked to the inflammatory process. Our findings highlight a genetic landscape that adapts to a hostile microenvironment, and demonstrate its potential contribution to the pathogenesis of ulcerative colitis.

Recent clinical and experimental evidence has evoked the concept of the gut–brain axis to explain mutual interactions between the central nervous system and gut microbiota that are closely associated with the bidirectional effects of inflammatory bowel disease and central nervous system disorders1–4. Despite recent advances in our understanding of neuroimmune interactions, it remains unclear how the gut and brain communicate to maintain gut immune homeostasis, including in the induction and maintenance of peripheral regulatory T cells (pTreg cells), and what environmental cues prompt the host to protect itself from development of inflammatory bowel diseases. Here we report a liver–brain–gut neural arc that ensures the proper differentiation and maintenance of pTreg cells in the gut. The hepatic vagal sensory afferent nerves are responsible for indirectly sensing the gut microenvironment and relaying the sensory inputs to the nucleus tractus solitarius of the brainstem, and ultimately to the vagal parasympathetic nerves and enteric neurons. Surgical and chemical perturbation of the vagal sensory afferents at the hepatic afferent level reduced the abundance of colonic pTreg cells; this was attributed to decreased aldehyde dehydrogenase (ALDH) expression and retinoic acid synthesis by intestinal antigen-presenting cells. Activation of muscarinic acetylcholine receptors directly induced ALDH gene expression in both human and mouse colonic antigen-presenting cells, whereas genetic ablation of these receptors abolished the stimulation of antigen-presenting cells in vitro. Disruption of left vagal sensory afferents from the liver to the brainstem in mouse models of colitis reduced the colonic pTreg cell pool, resulting in increased susceptibility to colitis. These results demonstrate that the novel vago-vagal liver–brain–gut reflex arc controls the number of pTreg cells and maintains gut homeostasis. Intervention in this autonomic feedback feedforward system could help in the development of therapeutic strategies to treat or prevent immunological disorders of the gut.

Various microbes having been living in our intestine and forming the gut microbiome. When dysbiosis which is typically characterized by reduced microbial diversity occurs, many types of diseases are triggered in our bodies. Recently, relationship between gut microbiome and our immune function are discovered gradually. From this view point, the gut microbiome may have an influence on cancer medicine such as development, therapy (immune checkpoint blockade or chemotherapy), and therapeutic toxicity. In real clinical practice, this influence is reported in some cases such as colorectal cancer and other malignancies. In the near future, the approach from gut microbiome may be a clue to improve the existent cancer diagnosis and therapy. In addition, the modulation of gut microbiome in itself, for example fecal microbiota transplant (FMT), probiotics, and limited usage of antibiotics, is expected to be hints for cancer medicine, though this is not yet established and further studies are needed.

© 2018 Future Medicine Ltd. Immune-related gastrointestinal toxicities (irGI) are well-known adverse events (AEs) with immune checkpoint inhibitors. The aim of this review was to present clinical data from 82 cases to provide information to clinicians who face real-world challenges among their patients with irGI AEs. The findings of this review support the use of the current management guidelines. By analyzing the treatment courses and outcomes of all cases identified, our review recommends that recurrent cases be treated carefully regardless of the grade of diarrhea at the onset of events. Earlier gastroenterology consultation and computed tomography/endoscopy diagnosis are essential, especially when an irGI AE recurs or worsens during steroid tapering. We would also suggest earlier decision to add immunosuppressant agents, particularly for recurrent cases.

© 2018 Japanese Journal of Cancer and Chemotherapy Publishers Inc. All Rights Reserved. Colitis is one of major adverse event induced by immune checkpoint inhibitor (ICPi), especially in the treatment with anti-CTLA-4 antibody. Colitis can occur anytime duringICPi therapy. The most common symptom is diarrhea. Other symptoms are abdominal pain, hematochezia, weight loss, fever and vomiting. To diagnoseICPi-induced colitis, it is important to deny infectious enterocolitis and tumor-related symptoms. Sigmoidoscopy or colonoscopy with biopsy are useful for proper diagnosis and evaluation of the severity. Patients with ulcer lesion tend to show resistance to steroid therapy. Diarrhea is an important symptom to evaluate the severity of colitis. American Society of Clinical Oncology and European Society for Medical Oncology published clinical guidelines for immune related adverse events including colitis. If patient has CTCAE Grade 2 or more severe diarrhea, both guidelines recommend stop ICPi and start corticosteroid therapy. As colitis can progress rapidly and induce perforation, the initiation of steroid therapy should not be hesitated. Some patients are resistant to steroid therapy, in which case infliximab, anti-TNF-a antibody, is recommended. ICPi-induced colitis is different from conventional adverse event induced by cytotoxic agents in terms of management with coticosteroid. Therefore, consultation to gastroenterologist is essential for proper diagnosis and corticosteroid initiation without delay.