Published papers

© 2020 American Society for Gastrointestinal Endoscopy Background and Aims: Since 2008, a plethora of research studies has compared the efficacy of water-assisted (aided) colonoscopy (WAC) and underwater resection (UWR) of colorectal lesions with standard colonoscopy. We reviewed and graded the research evidence with potential clinical application. We conducted a modified Delphi consensus among experienced colonoscopists on definitions and practice of water immersion (WI), water exchange (WE), and UWR. Methods: Major databases were searched to obtain research reports that could potentially shape clinical practice related to WAC and UWR. Pertinent references were graded (Grading of Recommendations, Assessment, Development and Evaluation). Extracted data supporting evidence-based statements were tabulated and provided to respondents. We received responses from 55 (85% surveyed) experienced colonoscopists (37 experts and 18 nonexperts in WAC) from 16 countries in 3 rounds. Voting was conducted anonymously in the second and third round, with ≥80% agreement defined as consensus. We aimed to obtain consensus in all statements. Results: In the first and the second modified Delphi rounds, 20 proposed statements were decreased to 14 and then 11 statements. After the third round, the combined responses from all respondents depicted the consensus in 11 statements (S): definitions of WI (S1) and WE (S2), procedural features (S3-S5), impact on bowel cleanliness (S6), adenoma detection (S7), pain score (S8), and UWR (S9-S11). Conclusions: The most important consensus statements are that WI and WE are not the same in implementation and outcomes. Because studies that could potentially shape clinical practice of WAC and UWR were chosen for review, this modified Delphi consensus supports recommendations for the use of WAC in clinical practice.

© 2017, Springer Science+Business Media LLC. The intestinal epithelium is the most rapidly renewed tissue in adult mammals, and its renewal is strictly controlled by intestinal stem cells. Extensive studies using genetic models of intestinal epithelium have revealed the mechanisms underlying the self-renewal of intestinal stem cells. Exploiting this knowledge, we developed a novel 3D culture system that enables the outgrowth of intestinal Lgr5+ stem cells derived from mouse and human tissues into ever-expanding crypt–villus mini-guts, known as intestinal epithelial organoids. These organoids are maintained by the self-renewal of stem cells and give rise to all differentiated cell types of the intestinal epithelium. Once established, organoids can be cryopreserved and thawed when needed. This culture system has been widely used for studying stem cell behavior and gene function and for disease modeling.

© 2017. Korean Association for the Study of Intestinal Diseases. All rights reserved. Background/Aims: Recent developments in analytical techniques including next-generation sequencing have clarified the correlation between intestinal microbiota and inflammatory bowel disease. Fecal microbiota transplantation (FMT) for patients with ulcerative colitis (UC) is proposed as a potential approach to resolving their dysbiosis; however, its safety and efficacy have not been confirmed. This single-arm, open-label, non-randomized study aimed to evaluate the safety and efficacy of FMT for Japanese patients with UC as the first registered clinical trial in Japan. Methods: We enrolled 10 patients with active UC despite medical therapy. The donors were the patients' relatives and were carefully screened for infectious diseases. Fecal material was administered via colonoscopy, and the primary endpoint was the presence or absence of serious adverse events related to FMT. The secondary endpoint was a change in partial Mayo score at 12 weeks post-FMT. Scores ≤2 were considered a clinical response. Fecal samples were collected to follow changes in gut microbiota, while extracted complementary DNA were analyzed by a next-generation sequencer. We obtained written informed consent from all patients and donors. This study was approved by our Institutional Review Board and is registered in the University hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN 000012814). Results: Five patients with moderate disease and five with severe disease were enrolled. No severe adverse effects were observed. One patient achieved clinical response; however, none of the patients' microbiota diversity recovered to the donor levels. Conclusions: The use of single FMT for UC was safe; however, we failed to show its clinical efficacy and potential to change the intestinal microbiota.

© 2016 Japan Gastroenterological Endoscopy Society Background and Aim: Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is characterized by periods of remission and episodes of relapse. Mucosal healing is an emerging therapeutic target in UC and various scoring systems have been used. The UC endoscopic index of severity (UCEIS) is the only validated endoscopic index at present, with minimum interobserver variation. Correlation of UCEIS scores after treatment and clinical outcomes of UC has not been examined. In the present study, we aimed to evaluate the usefulness of UCEIS after treatment with infliximab. Methods: The medical records of 82 UC patients, treated with infliximab at Keio University Hospital between October 2010 and July 2013, were reviewed retrospectively. Endoscopic findings were evaluated based on the UCEIS. Results: Mean pre-therapeutic UCEIS score was 5.1. Pre-therapeutic UCEIS scores were not associated with short-term outcomes. Forty-five patients underwent colonoscopy at 3–12 months after starting treatment; mean post-therapeutic UCEIS score was 2.4, with a score of 0–1 in 16 (35.6%) patients, 2–4 in 19 (42.2%) patients, and 5–8 in 10 (22.2%) patients. Importantly, a post-therapeutic UCEIS score of 0 or 1 after treatment was associated with a favorable long-term outcome. Conclusion: UCEIS score is a useful instrument for evaluating endoscopic improvement in UC patients treated with infliximab, and mucosal healing may be defined with a UCEIS score of 0 or 1.

© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. The cancer stem cell (CSC) theory highlights a self-renewing subpopulation of cancer cells that fuels tumour growth. The existence of human CSCs is mainly supported by xenotransplantation of prospectively isolated cells, but their clonal dynamics and plasticity remain unclear. Here, we show that human LGR5 + colorectal cancer cells serve as CSCs in growing cancer tissues. Lineage-tracing experiments with a tamoxifen-inducible Cre knock-in allele of LGR5 reveal the self-renewal and differentiation capacity of LGR5 + tumour cells. Selective ablation of LGR5 + CSCs in LGR5-iCaspase9 knock-in organoids leads to tumour regression, followed by tumour regrowth driven by re-emerging LGR5 + CSCs. KRT20 knock-in reporter marks differentiated cancer cells that constantly diminish in tumour tissues, while reverting to LGR5 + CSCs and contributing to tumour regrowth after LGR5 + CSC ablation. We also show that combined chemotherapy potentiates targeting of LGR5 + CSCs. These data provide insights into the plasticity of CSCs and their potential as a therapeutic target in human colorectal cancer.

Background and Aims: Diffuse-type gastric cancer (GC) is currently subdivided into signet-ring cell carcinoma (SRCC) and non-SRCC, referred to as poorly cohesive carcinoma not otherwise specified (PCC-NOS). Although these subtypes are considered to be independent, they often coexist in the same tumors, raising a question of whether they clonally differ or not. To tackle this question, we established an experimental platform for human diffuse GC that enables accurate modeling of histologic subtypes. Methods: Seven patient-derived diffuse GC organoid lines were established, characterized by histopathologic analysis, in situ hybridization, and gene expression analysis. For genetic modeling of diffuse GC, we knocked out CDH1 and/or TP53 in human normal gastric organoids. Green fluorescent protein–labeled GC organoids were xenotransplanted into immune-deficient mice for in vivo assessment. Results: PCC-NOS organoids transformed into SRCC-like structures on removal of Wnt and R-spondin from the culture medium. This morphologic change paralleled downregulation of Wnt-target and gastric stem cell genes, including LGR5, and elevation of differentiation markers, such as KRT20 and MUCs. The association between Wnt target gene expression and histologic subtypes was confirmed in 3 patient-derived GC tissues. In vivo, single clone-derived organoids formed tumors that comprised 2 distinct histologic compartments, each corresponding to SRCC and PCC-NOS. The transition from PCC-NOS to SRCC histology reflected the abundance of surrounding R-spondin–expressing fibroblasts. Conclusions: SRCC and PCC-NOS were clonally identical, and their morphology was regulated by extracellular Wnt and R-spondin expression. Our results decoded how genetic mutations and the tumor environment shape pathohistologic and biologic phenotypes in human diffuse GCs.

© 2013, The Author(s). A 41-year-old man with no familial history of gastric cancer was diagnosed as with intramucosal early gastric cancer. Two months after the first endoscopic submucosal dissection for signet-ring cell carcinoma (SRCC), the appearance of previously unrecognized multiple erosions of SRCC was noticed. Pathological examination after a total gastrectomy and Roux-en-Y reconstruction with D2 lymph node dissection were performed. Postoperative pathological examination revealed 90 and more lesions, which tempted the attending pathologist to refer to genetic tests for the predisposition though the patient had no familial history of gastric cancer. There were no mutations in all the exons of CDH1 with conventional DNA sequencing, but multiplex ligation-dependent probe amplification, and reverse transcription-polymerase chain reaction analyses disclosed a large genomic deletion (c.1566-?_1711+?del), leading to the mRNA with loss of the exon 11. Among family members, his son was found to be a carrier of this change, while his parents were negative for the familial CDH1 mutation, implying that this change is a de novo event in the proband. The present report is the first description of a de novo large genomic deletion of CDH1 gene associated with early-onset diffuse gastric cancer. When the clinician finds a relatively-young patient who has multiple SRCCs, CDH1 germline mutation should be considered, even for patients with no familial history.

© Georg Thieme Verlag KG Stuttgart New York. Background and study aim Endocytoscopy (ECS) is used in the in vivo microscopic inspection of microstructural mucosal features and enables endoscopists to assess the histological severity of ulcerative colitis (UC). The aim of this study was to assess histological healing in UC patients by using ECS. Patients and methods A total of 64 patients in clinical and endoscopic remission who underwent ECS were selected. The correlation between the ECS score and Geboes score at the rectum was evaluated in patients with a Mayo endoscopic score (MES) of 0.The diagnostic accuracy of the ECS score for histological remission (Geboes score ≤2) was also assessed. Results The ECS score ranged from 0 to 5 in patients with endoscopic remission on conventional white-light images (MES of 0). The agreement between histological remission regarding the ECS score and the Geboes score had a κ value of 0.72, and the ECS score showed high accuracy for histological remission, with a sensitivity of 0.77, a specificity of 0.97, and a diagnostic accuracy of 0.86. Conclusion ECS can be used to assess histological healing in patients with UC without the need for biopsy specimens.

© 2017 American Society for Gastrointestinal Endoscopy Background and Aims Recent advances in endoscopic equipment and diagnostic techniques have made possible the detection of early dysplasia in the inflamed mucosa of ulcerative colitis (UC). The SCENIC consensus statement recommends the use of unified terminology for the morphology of dysplasia. In this study, we investigated the endoscopic features of high-grade dysplasia (HGD) in a clinical setting. Methods We retrospectively identified 62 patients with UC who were diagnosed with colitis-associated cancer or HGD between 1997 and 2015. A total of 39 lesions of HGD detected by targeted biopsy sampling in 31 patients were reviewed, and the endoscopic morphology was classified according to the SCENIC guidelines. Results In total, 0 (0%), 6 (15.4%), 19 (48.7%), 12 (30.8%), and 2 (5.1%) lesions with HGD were classified as pedunculated, sessile, superficial elevated, flat, and depressed, respectively. Nearly 80% of the lesions were located in the rectum or sigmoid colon. All flat and depressed lesions were red in color. Typically, sessile/superficial elevated lesions accompanied a flat area (Is+IIb/IIa+IIb). Ulceration was observed in 2 depressed lesions (5.1%). Although the borders were indistinct in 21 lesions (53.8%) without the use of magnifying colonoscopy, all lesions could be distinguished from the surrounding mucosa using magnifying endoscopy. Conclusions This is the first study to classify the morphologic features of HGD using the SCENIC guidelines in a clinical setting. Based on our findings, endoscopists should recognize that HGD is frequently associated with a flat/superficial elevated area and red discoloration and should inspect particularly carefully in the rectum and sigmoid colon. The findings of chromoendoscopy and magnifying colonoscopy may also be useful in distinguishing lesions from the surrounding mucosa.

© 2016 © 2016 S. Karger AG, Basel. Introduction: Mucosal healing has emerged as a desirable treatment goal in clinical practice for patients with Crohn's disease (CD). The aim of this study was to assess the relationship between endoscopic activity and the long-term prognosis of CD using simple endoscopic score for Crohn's disease (SESCD) and Rutgeerts' score. Methods: We conducted a cohort study in clinical practice at a single center. Among CD patients who underwent colonoscopy between July 2008 and June 2011 at our hospital, 131 patients with clinical remission were selected, and the patients were divided into 2 groups: a non-surgical group (n = 84) and a surgical group (n = 47). The primary endpoint of this study was to assess the associations between variables and clinical relapse after endoscopic procedures. The cut-off levels of SESCD or Rutgeerts' score for the prediction of relapse were also assessed in patients with clinical remission. Results: In the non-surgical group, SESCD and C-reactive protein at baseline were significantly higher in patients who had clinical recurrence than in patients who maintained remission. A factor of SESCD ≤2 was independently associated with sustained remission, even in patients with clinical remission. In the surgical group, patients with Rutgeerts' scores ≤1 had significantly prolonged clinical remission compared to patients with Rutgeerts' scores ≥3. Conclusion: A cut-off value of SESCD ≤2 and a Rutgeerts' score ≤1 enabled the prediction of long-term prognosis. These cut-off values could be used in clinical trials of endoscopic remission from the point of view of the clinical outcomes of CD.

© 2016, Japanese Society of Gastroenterology. Indole compounds are extracted from indigo plants and have been used as blue or purple dyes for hundreds of years. In traditional Chinese medicine, herbal agents in combination with Qing-Dai (also known as indigo naturalis) have been used to treat patients with ulcerative colitis (UC) and to remedy inflammatory conditions. Recent studies have noted that indole compounds can be biosynthesized from tryptophan metabolites produced by various enzymes derived from intestinal microbiota. In addition to their action on indole compounds, the intestinal microbiota produce various tryptophan metabolites that mediate critical functions through distinct pathways and enzymes. Furthermore, some indole compounds, such as indigo and indirubin, act as ligands for the aryl hydrocarbon receptor. This signaling pathway stimulates mucosal type 3 innate lymphoid cells to produce interleukin-22, which induces antimicrobial peptide and tight junction molecule production, suggesting a role for indole compounds during the mucosal healing process. Thus, indole compounds may represent a novel treatment strategy for UC patients. In this review, we describe the origin and function of this indole compound-containing Chinese herb, as well as the drug development of indole compounds.

© 2016, Japanese Society of Gastroenterology. Recently, several medical treatments for ulcerative colitis (UC) have been developed, including 5-aminosalicylic acids (5-ASAs), corticosteroids, thiopurine, calcineurin inhibitors, and anti-tumor necrosis factor (TNF) α treatments. Treatment options including calcineurin inhibitors and anti-TNF treatment for refractory UC are discussed in this article. Furthermore, upcoming treatments are introduced, such as golimumab, vedolizumab, AJM300, tofacitinib. Budesonide foamwill be used as one treatment option in patients with distal colitis. Herbal medicine, such as Qing-Dai is also effective for active UC and may be useful for patients who are refractory to anti-TNFα treatments. In the near future, physicians will able to use many different treatments for UC patients. However, we should not forget 5-ASA and corticosteroids as the fundamental treatments for UC patients.

© 2015, Springer Japan. In East Asian countries, gastric cancer incidence is high, but detection rates for germline CDH1 mutations that cause hereditary diffuse gastric cancers (HDGCs) are low. Consequently, screens and genetic testing for HDGC are often considered unimportant. Since the first germline truncating CDH1 mutations in Japanese patients were reported, some HDGC cases have been reported, and some of these involve large germline rearrangements and de novo mutation of CDH1. New methods for mutation detection—such as multiplex ligation-dependent probe amplification, array comparative genomic hybridization, and exome sequencing—have become available, as have new experimental models, including novel gene-knockout mice and gastric organoids. Because of these advances, searches for candidate genes (e.g., CTNNA1, MAP3K6) and our understanding of HDGC pathogenesis have improved in recent years; moreover, there have been substantial changes in the field since the current HDGC consensus guidelines were released. This review focuses on recent issues and advances in the study of HDGC. For example, lobular breast cancer cases and de novo occurrences of DGC are unlikely to meet the existing criteria for genetic testing, but current evidence indicates that some such cases may be good candidates for genetic testing. It is important to recognize that HDGC is a syndrome and that lobular breast cancer can be the first manifestation of this syndrome. CDH1 testing, including analyses of large genomic rearrangements, should be recommended even in countries where few HDGC cases have been reported.

© 2019, Japanese Society of Gastroenterology. Background: Apheresis therapy involves the selective removal of leukocytes and is used to induce remission in ulcerative colitis (UC) patients. The aim of this study was to demonstrate the efficacy and safety of apheresis therapy for maintaining UC remission. Methods: We conducted a multicenter, prospective, randomised-control trial of patients with remitting UC induced by granulocyte and monocyte adsorption apheresis or leukocytapheresis. Patients were randomly assigned to the apheresis group (twice per month for 12 months) or the control group (no apheresis treatment) using a 1:1 allocation ratio. The primary endpoint was the rate of cumulative clinical remission (Mayo score ≤ 2) at 12 months. The secondary endpoints were the rates of clinical remission, endoscopic remission, and complete endoscopic remission at 12 months. Results: Between March 2013 and March 2017, 164 patients were enrolled. The cumulative remission rate at 12 months was 46.6% in the apheresis group and 36.4% in the control group (p = 0.1621). The rate of endoscopic remission at 12 months was significantly higher in the apheresis group than in the control group (42.5% vs. 25.9%) p = 0.0480). The rate of clinical remission (47.5% vs.32.1%, p = 0.0540) and complete endoscopic remission (33.8% vs.19.8%, p = 0.0513) tended to be higher in the apheresis than in the control group; however, the difference was not significant. No severe adverse events were observed in either group. Conclusions: Apheresis was well tolerated as maintenance therapy for UC although the cumulative clinical remission rate at 12 months was comparable between the apheresis and control groups.

Intestinal stem cells continuously self-renew throughout life to maintain gut homeostasis. With the advent of the organoid culture system, we are now able to indefinitely expand healthy and diseased tissue-derived human intestinal stem cells in vitro and use them for various applications. Nonetheless, investigating the behavior of human intestinal stem cells in vivo still remains challenging. We recently developed an orthotopic xenotransplantation system that realizes in vivo reconstruction of human intestinal epithelial tissue with preserved stem cell hierarchy by engrafting human normal colon organoids onto the mouse colon surface. We also introduced new growth factors, namely, insulin-like growth factor-1 (IGF-1) and fibroblast growth factor-2 (FGF-2), into the culture condition for human intestinal organoids that significantly increase scalability and transfectability of the organoids. By integrating these recent advances, we organized a tissue-oriented platform encompassing derivation of patient-derived intestinal organoids and their orthotopic xenotransplantation. The research platform based on orthotopic xenotransplantation of human intestinal organoids provides a powerful tool for studying human intestinal stem cell biology in native tissue-relevant contexts as well as for establishing novel disease modeling systems.

© 2016 The Author(s) Published by S. Karger AG, Basel. Background/Aims: Chinese herbal medicine Qing-Dai (also known as indigo naturalis) has been used to treat various inflammatory conditions. However, not much has been studied about the use of oral Qing-Dai in the treatment for ulcerative colitis (UC) patients. Studies exploring alternative treatments for UC are of considerable interest. In this study, we aimed at prospectively evaluating the safety and efficacy of Qing-Dai for UC patients. Methods: The open-label, prospective pilot study was conducted at Keio University Hospital. A total of 20 patients with moderate UC activity were enrolled. Oral Qing-Dai in capsule form was taken twice a day (daily dose, 2 g) for 8 weeks. Results: At week 8, the rates of clinical response, clinical remission, and mucosal healing were 72, 33, and 61%, respectively. The clinical and endoscopic scores, CRP levels, and fecal occult blood results were also significantly improved. We observed 2 patients with mild liver dysfunction; 1 patient discontinued due to infectious colitis and 1 patient discontinued due to mild nausea. Conclusion: This is the first prospective study indicating that oral Qing-Dai is effective for inducing remission in patients with moderate UC activity and can be tolerated. Thus, Qing-Dai may be considered an alternative treatment for patients, although further investigation is warranted.

© 2017. Korean Association for the Study of Intestinal Diseases. Background/Aims: Colonoscopy and computed tomography (CT) are used primarily to exclude organic diseases in patients with irritable bowel syndrome (IBS), rather than to assess the pathophysiology of IBS. We aimed to evaluate colonic dysmotility and morphology in Japanese patients with IBS. Methods: One hundred eighty-four patients with IBS and 49 asymptomatic controls who underwent colonoscopy in combination with CT colonography or barium enema were retrospectively reviewed between 2008 and 2012. Water-aided colonoscopy was performed without sedation by a single endoscopist. The duration and pattern of colonic movement and cecal intubation time were recorded. To assess colonic morphology, barium enema or CT colonography were performed immediately after colonoscopy. Results: Colonic dysmotility was more frequent in the IBS group (28.8% vs. 2.0% in controls, P <0.001), especially in cases of IBS with diarrhea (IBS-D) (IBS with constipation [IBS-C] 28.8% vs. IBS-D 60.0% vs. mixed IBS [IBS-M] 5.1%, P <0.001). Colonic morphological abnormality was more frequent in the IBS group than in the control group (77.7% vs. 24.5%, P <0.001), especially in IBS-M and IBS-C groups (IBS-C 77.5% vs. IBS-D 48.9% vs. IBS-M 100%, P <0.001). Most patients with IBS with colonic dysmotility had experienced stress related to their symptoms. Cecal intubation time was significantly longer in the IBS group than in the control group (12.1±6.9 minutes vs. 4.6±1.9 minutes, P <0.001). Conclusions: Unsedated colonoscopy, combined with radiographic findings, can detect colonic dysmotility and morphological abnormality. Technical difficulties observed during cecal intubation may partially explain the pathophysiology of IBS.

© The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved. Colonoscopy techniques combining or replacing air insufflation with water infusion are becoming increasingly popular. They were originally designed to reduce colonic spasms, facilitate cecal intubation, and lower patient discomfort and the need for sedation. These maneuvers straighten the rectosigmoid colon and enable the colonoscope to be inserted deeply without causing looping of the colon. Water-immersion colonoscopy minimizes colonic distension and improves visibility by introducing a small amount of water. In addition, since pain during colonoscopy indicates risk of bowel perforation and sedation masks this important warning, this method has the potential to be the favored insertion technique because it promotes patient safety without sedation. Recently, this water-immersion method has not only been used for colonoscope insertion, but has also been applied to therapy for sigmoid volvulus, removal of lesions, lower gastrointestinal bleeding, and therapeutic diagnosis of abnormal bowel morphology and irritable bowel syndrome. Although a larger sample size and prospective head-to-head-designed studies will be needed, this review focuses on the usefulness of water-immersion colonoscopy for diagnostic and therapeutic applications.