Efficacy of Glycicumarin and Isoliquiritigenin in Suppressing Colonic Peristalsis in Both an Animal Model and a Clinical Trial.

Patients with diarrhea-predominant irritable bowel syndrome (IBS-D) show excessive peristalsis, and antispasmodic agents may be useful therapeutic agents. There are few reports on the use of Kampo medicines for the treatment of IBS-D. Shakuyakukanzoto (SKT) is a Kampo medicine that is effective against abdominal pain. We examined the relationship between SKT and intestinal peristalsis in an animal model and a prospective study. In the animal model, SKT and its components were administered from the serosal side of the colon and colonic peristalsis was evaluated using intraluminal pressure and spatiotemporal mapping before and after the administration of SKT and its components. In this clinical trial, we used abdominal ultrasonography (US) to obtain long-axis images of the sigmoid colon of 11 patients. The frequency of intestinal peristalsis was measured using US in five patients with SKT and six patients without medication after the ingestion of a test meal. The primary outcome was the frequency of peristalsis. The Clinical Trial Registry Website (Trial No. UMIN-CTR; UMIN000051547). In the animal model, peony did not suppress peristalsis frequency, but SKT (p = 0.005) and glycyrrhiza (p = 0.001) significantly suppressed peristalsis frequency compared with saline and peony. Among the glycyrrhiza components, glycycoumarin and isoliquiritigenin suppressed the peristalsis frequency compared to dimethyl sulfoxide (control) (p = 0.001, 0.01, respectively). In a clinical trial, peristalsis was significantly suppressed after oral administration in patients taking SKT (p = 0.03). Administration of SKT was found to inhibit colonic peristalsis, with glycicumarin and isoliquiritigenin being particularly relevant among its components.

D-alanine inhibits murine intestinal inflammation by suppressing IL-12 and IL-23 production in macrophages.

BACKGROUND AND AIMS: Free D-amino acids, which have different functions from L-amino acids, have recently been discovered in various tissues. However, studies on the potential interactions between intestinal inflammation and D-amino acids are limited. We examined the inhibitory effects of D-alanine on the pathogenesis of intestinal inflammation. METHODS: We investigated serum D-amino acid levels in 40 patients with ulcerative colitis and 34 healthy volunteers. For 7 d, acute colitis was induced using dextran sulfate sodium in C57BL/6J mice. Plasma D-amino acid levels were quantified in mice with dextran sulfate sodium-induced colitis, and these animals were administered D-alanine via intraperitoneal injection. IFN-γ, IL-12p35, IL-17A, and IL-23p19 mRNA expression in the colonic mucosa was measured using real-time PCR. In vitro proliferation assays were performed to assess naïve CD4+ T cell activation under Th-skewing conditions. Bone marrow cells were stimulated with mouse macrophage-colony stimulating factor to generate mouse bone marrow-derived macrophages. RESULTS: Serum D-alanine levels were significantly lower in patients with ulcerative colitis than in healthy volunteers. Dextran sulfate sodium-treated mice had significantly lower plasma D-alanine levels than control mice. D-alanine-treated mice had significantly lower disease activity index than control mice. IFN-γ, IL-12p35, IL-17A, and IL-23p19 mRNA expression levels were significantly lower in D-alanine-administered mice than in control mice. D-alanine suppressed naïve T cell differentiation into Th1 cells in vitro and inhibited the production of IL-12p35 and IL-23p19 in bone marrow-derived macrophages. CONCLUSIONS: Our results suggest that D-alanine prevents dextran sulfate sodium-induced colitis in mice and suppresses IL-12p35 and IL-23p19 production in macrophages.

Characteristics of Gastric Mucosa-Associated Microbiota in Patients with Early Gastric Cancer After Successful Helicobacter pylori Eradication.

BACKGROUND: Helicobacter pylori (H. pylori) is widely recognized as a definite carcinogen in gastric cancer (GC). Although H. pylori eradication reduces the risk of GC, GC recurrence has been detected even after successful H. pylori eradication. Recently, the analysis of gut microbiota was reported. AIMS: This study aimed to evaluate the correlation between gastric mucosa-associated microbiota (G-MAM) and early gastric cancer (EGC) after successful H. pylori eradication. METHODS: In this pilot study, G-MAM were collected during the esophagogastroduodenoscopy of 17 patients, receiving H. pylori eradication therapy at least 5 years ago. The patients were divided into those with EGC (the EGC group, 8 patients) and those without EGC (the NGC group, 9 patients). Microbial samples in the greater curvature of the pyloric site were obtained using an endoscopic cytology brush, and the G-MAM profiles of each sample were analyzed using 16S rRNA V3-V4 gene sequencing. RESULTS: Between the two groups, there was no significant difference in the median age, sex, median period after successful eradication of H. pylori, the α diversity, and the average abundance at the phylum level. At the genus level, the average abundance of Unclassified Oxalobacteraceae, Capnocytophaga, and Haemophilus was significantly lower in the EGC group than in the NGC group (0.89 vs. 0.14%, P < 0.01, 0.28 vs. 0.00%, P < 0.01 and 5.84 vs. 2.16%, P = 0.034, respectively). CONCLUSIONS: We demonstrated alternations in the profiles of G-MAM between the two groups. Our results suggest that G-MAM may influence carcinogenesis after successful H. pylori eradication.

Clinical Background Factors as Predictors of the Efficacy of 5-Aminosalicylic Acid Suppositories in Patients with Ulcerative Colitis.

Introduction: Although the efficacy of 5-aminosalicylic acid (ASA) suppositories for ulcerative colitis (UC) has been reported in many studies, many studies have also described poor adherence to 5-ASA suppository regimens. We aimed to identify the clinical background factors that influence adherence to 5-ASA suppositories to improve adherence and efficacy of the treatment. Methods: We conducted a retrospective cohort study of 61 patients with active UC who were using 5-ASA suppositories. All patients underwent endoscopy and rectal biopsy for histological diagnosis prior to 5-ASA suppository treatment. The efficacy of 5-ASA suppository treatment was compared in relation to clinical background factors (sex, age, disease duration, disease type, clinical activity, Ulcerative Colitis Endoscopic Index of Severity, histological activity, serum C-reactive protein level, concomitant use of immunomodulators, history of steroid use, and dose of oral 5-ASA). Results: The efficacy of 5-ASA suppositories was significantly related to low Lichtiger Colitis Activity Index (LCAI) scores and proctitis type prior to its use. In terms of sex, females tended to show higher efficacy. Multivariate logistic regression analysis using these three factors showed high predictive value for the efficacy of 5-ASA suppositories (AUC, 0.788; sensitivity, 87.2%; and specificity, 63.7%). Conclusion: This study is the first to extract clinical background factors for predicting the efficacy of 5-ASA suppositories. The use of 5-ASA suppositories in patients who are expected to show efficacy will be effective in improving patient co-operation.

Differences in gene regulation by TLR3 and IPS-1 signaling in murine corneal epithelial cells.

Toll-like receptor 3 (TLR3) and interferon-beta promoter stimulator-1 (IPS-1) are associated with antiviral responses to double-stranded RNA viruses and contribute to innate immunity. We previously reported that conjunctival epithelial cell (CEC) TLR3 and IPS-1 pathways respond to the common ligand polyinosinic:polycytidylic acid (polyI:C) to regulate different gene expression patterns as well as CD11c + cell migration in murine-model corneas. However, the differences in the functions and the roles of TLR3 and IPS-1 remain unclear. In this study, we investigated the differences of TLR3 or IPS-1-induced gene expression in corneal epithelial cells (CECs) in response to polyI:C stimulation using cultured murine primary CECs (mPCECs) derived from TLR3 and IPS-1 knockout mice via comprehensive analysis. The genes associated with viral responses were upregulated in the wild-type mice mPCECs after polyI:C stimulation. Among these genes, Neurl3, Irg1, and LIPG were dominantly regulated by TLR3, while interleukin (IL)-6 and IL-15 were dominantly regulated by IPS-1. CCL5, CXCL10, OAS2, Slfn4, TRIM30α, and Gbp9 were complementarily regulated by both TLR3 and IPS-1. Our findings suggest that CECs may contribute to immune responses and that TLR3 and IPS-1 possibly have different functions in the corneal innate immune response.

A newly developed solution for the preservation of short-chain fatty acids, bile acids, and microbiota in fecal specimens.

Recent studies have revealed that the gut microbiome affects various health conditions via its metabolites, including short-chain fatty acids (SCFAs) and bile acids (BAs). In the analysis of these, appropriate collection, handling, and storage of fecal specimens are required, and convenient specimen handling processes will facilitate their investigation. Here, we developed a novel preservation solution, "Metabolokeeper®", to stabilize fecal microbiota, organic acids including SCFAs, and BAs at room temperature. In the present study, we collected fecal samples from 20 healthy adult volunteers and stored them at room temperature with Metabolokeeper® and at -80°C without preservatives for up to four weeks to evaluate the usefulness of the novel preservative solution. We found that microbiome profiles and short chain fatty acid contents were stably maintained at room temperature with Metabolokeeper® for 28 days, while the bile acids were stably maintained for 7 days under the same conditions. We conclude that this convenient procedure to obtain a fecal sample for collecting the gut microbiome and gut metabolites can contribute to a better understanding of the health effects of fecal metabolites produced by the gut microbiome.

Exercise-acclimated microbiota improves skeletal muscle metabolism via circulating bile acid deconjugation.

Habitual exercise alters the intestinal microbiota composition, which may mediate its systemic benefits. We examined whether transplanting fecal microbiota from trained mice improved skeletal muscle metabolism in high-fat diet (HFD)-fed mice. Fecal samples from sedentary and exercise-trained mice were gavage-fed to germ-free mice. After receiving fecal samples from trained donor mice for 1 week, recipient mice had elevated levels of AMP-activated protein kinase (AMPK) and insulin growth factor-1 in skeletal muscle. In plasma, bile acid (BA) deconjugation was found to be promoted in recipients transplanted with feces from trained donor mice; free-form BAs also induced more AMPK signaling and glucose uptake than tauro-conjugated BAs. The transplantation of exercise-acclimated fecal microbiota improved glucose tolerance after 8 weeks of HFD administration. Intestinal microbiota may mediate exercise-induced metabolic improvements in mice by modifying circulating BAs. Our findings provide insights into the prevention and treatment of metabolic diseases.

Partially hydrolyzed guar gum increased colonic mucus layer in mice via succinate-mediated MUC2 production.

Colonic mucus layers protect intestinal tissues against intestinal bacteria. We investigated the effects of dietary fiber and its metabolites on mucus production in the colonic mucosa. Mice were fed a partially hydrolyzed guar gum (PHGG)-containing diet and a fiber-free diet (FFD). The colon mucus layer, fecal short-chain fatty acid (SCFA) levels, and gut microbiota were evaluated. Mucin 2 (MUC2) expression was assessed in SCFA-treated LS174T cells. The role of AKT in MUC2 production was investigated. The mucus layer in the colonic epithelium was significantly increased in the PHGG group compared with that in the FFD group. In the PHGG group, an increase in Bacteroidetes in the stool was observed, and fecal acetate, butyrate, propionate, and succinate levels were significantly increased. However, MUC2 production was significantly increased only in succinate-stimulated LS174T cells. The succinate-induced MUC2 production was associated with AKT phosphorylation. Succinate mediated the PHGG-induced increase in the colon mucus layer.

Mucosal Addressin Cell Adhesion Molecule 1 Expression Reflects Mucosal Inflammation and Subsequent Relapse in Patients with Ulcerative Colitis.

BACKGROUND AND AIMS: Mucosal addressin cell adhesion molecule 1 [MAdCAM-1] is upregulated in the vascular endothelium of the colonic mucosa in ulcerative colitis [UC]. Although the association between MAdCAM-1 expression and mucosal inflammation has been discussed, the association with the clinical course of UC patients has not been reported. In this study we investigated not only the association between mucosal MAdCAM-1 expression and mucosal inflammation, but also its association with subsequent relapse in UC patients with clinical remission. METHODS: Eighty UC patients in remission who visited Kyoto Prefectural University of Medicine for follow-up for 2 years were included. Biopsy samples were collected during colonoscopy, and transcriptional expression levels of UC-related cytokines and MAdCAM-1 were quantified using real-time polymerase chain reaction. MAdCAM-1 mRNA expression and protein expression by immunohistochemistry were compared in patients who subsequently relapsed and those who remained in remission and were examined in relation to endoscopic findings, histological activity and cytokine expression. RESULTS: MAdCAM-1 expression was correlated with endoscopic severity, and significantly elevated in histologically active mucosa than inactive mucosa. Furthermore, MAdCAM-1 expression levels were closely correlated with those of several cytokines. MAdCAM-1 mRNA and protein expression were significantly higher in the relapse group than in the remission group, indicating that MAdCAM-1 expression in the mucosa is already elevated in UC patients in clinical remission who subsequently relapse. CONCLUSIONS: MAdCAM-1 expression in the colonic mucosa of UC patients is related to mucosal inflammation and subsequent relapse; it may serve as a marker for both relapse and therapeutic effectiveness in UC.

Astaxanthin attenuated the stress-induced intestinal motility disorder via altering the gut microbiota.

Gut microbiota and short-chain fatty acids (SCFAs) are recognized as key factors in the pathophysiology of irritable bowel syndrome. Astaxanthin is a carotenoid with strong antioxidant and anti-inflammatory activities. In this study, we examined the effects of astaxanthin on gut microbiota-, SCFAs-, and corticotropin-releasing factor (CRH)-induced intestinal hypermotility. Male Wistar rats (n=12 per group) were fed a diet with or without 0. 02% (w/w) astaxanthin for four weeks and CRH or saline was administered intravenously. The number of fecal pellets was counted 2 h after injection. Then the rats were sacrificed, and the cecal content were collected 3 h after injection. The number of feces was significantly increased by CRH injection in the control group (2.0 vs. 6.5; p=0.028), but not in the astaxanthin group (1.0 vs. 2.2; p=0.229) (n=6 per group). The cecal microbiota in the astaxanthin group was significantly altered compared with that in the control group. The concentrations of acetic acid (81.1 µmol/g vs. 103.9 µmol/g; p=0.015) and butyric acid (13.4 µmol/g vs. 39.2 µmol/g; p<0.001) in the astaxanthin group were significantly lower than that in the control group (n=12 per group). Astaxanthin attenuates CRH-induced intestinal hypermotility and alters the composition of gut microbiota and SCFAs.

Effects of Smoking on the Gut Microbiota in Individuals with Type 2 Diabetes Mellitus.

Smoking affects eating habits; however, few studies on smoking and the gut microbiota have reported the effects of diet in detail. This cross-sectional study aimed to determine the association between smoking and the gut microbiota, considering the impact of smoking on dietary intake. Dietary habits and the composition of the gut microbiota were assessed in 195 men with type 2 diabetes (164 non-current smokers and 31 current smokers) using a brief self-administered diet history questionnaire and 16S ribosomal RNA gene sequencing of fecal samples. The data were compared according to the current smoking status of the participants. Current smokers had high alcohol and sugar/sweetener intake and low fruit intake. The proportion of the Coprococcus genus was higher among current smokers. Multiple regression analysis adjusted for current smoking, age, exercise habits, alcohol intake, sugar and sweetener intake, and fruit intake showed that smoking was associated with the proportion of the Coprococcus genus. Current smoking was associated with both dietary intake and composition of the gut microbiota. Although dietary intake should be considered when investigating the association between smoking and the gut microbiota, the results suggest that the direct effect of smoking is more significant.

Retrospective investigation of mesalamine intolerance in patients with ulcerative colitis.

Mesalamine is a key drug in the treatment of ulcerative colitis (UC) for both induction and maintenance therapy. On the other hand, it is known that there are some cases of mesalamine intolerance that are difficult to distinguish from symptoms due to aggravation of UC. The aim of this study is to investigate the clinical characteristic of mesalamine intolerance in UC. A retrospective, observational study was conducted. We enrolled 31 patients who were diagnosed as mesalamine intolerance between April 2015 to March 2020. We examined clinical features, time to onset, drug types of mesalamine, DLST positive rate, colonoscopy findings, disease activity, and clinical course after diagnosis. The average dose of mesalamine was 3.69 g and DLST-positive was 57.1%. Within the first 2 weeks from the start of mesalamine, 51.6% showed symptoms of intolerance. The serum CRP level was relatively high at ≥10.0 mg/dl in 53.6% of the cases. There was no difference in clinical background, symptoms, or laboratory findings between patients with DLST-positive and negative. In this study, we clarified the clinical characteristics of mesalamine intolerant patients, and found no difference in the clinical background or success rate of desensitization therapy between positive and negative DLST cases.

Association Between the Cool Temperature-dependent Suppression of Colonic Peristalsis and Transient Receptor Potential Melastatin 8 Activation in Both a Randomized Clinical Trial and an Animal Model.

Background/Aims: Several studies have assessed the effect of cool temperature on colonic peristalsis. Transient receptor potential melastatin 8 (TRPM8) is a temperature-sensitive ion channel activated by mild cooling expressed in the colon. We examined the antispasmodic effect of cool temperature on colonic peristalsis in a prospective, randomized, single-blind trial and based on the video imaging and intraluminal pressure of the proximal colon in rats and TRPM8-deficient mice. Methods: In the clinical trial, we randomly assigned a total of 94 patients scheduled to undergo colonoscopy to 2 groups: the mildly cool water (n = 47) and control (n = 47) groups. We used 20 mL of 15°C water for the mildly cool water. The primary outcome was the proportion of subjects with improved peristalsis after treatment. In the rodent proximal colon, we evaluated the intraluminal pressure and performed video imaging of the rodent proximal colon with cool water administration into the colonic lumen. Clinical trial registry website (Trial No. UMIN-CTR; UMIN000030725). Results: In the randomized controlled trial, after treatment, the proportion of subjects with no peristalsis with cool water was significantly higher than that in the placebo group (44.7% vs 23.4%; P < 0.05). In the rodent colon model, cool temperature water was associated with a significant decrease in colonic peristalsis through its suppression of the ratio of peak frequency (P < 0.05). Cool temperature-treated TRPM8-deficient mice did not show a reduction in colonic peristalsis compared with wild-type mice. Conclusion: For the first time, this study demonstrates that cool temperature-dependent suppression of colonic peristalsis may be associated with TRPM8 activation.

Oligosaccharides from agar extends lifespan through activation of unfolded protein response via SIR-2.1 in Caenorhabditis elegans.

PURPOSE: Agaro-oligosaccharides (AGO), hydrolysis products of agarose, is known to have antioxidant and anti-inflammatory properties. Speculating that AGO is effective for preventing aging, we investigated the longevity-supporting effects of AGO and their mechanisms using Caenorhabditis elegans. METHODS: Caenorhabditis elegans were fed AGO from young adulthood. The lifespan, locomotory activity, lipofuscin accumulation, and heat stress resistance of the worms were examined. To elucidate mechanisms of AGO-mediated longevity, we conducted comprehensive expression analysis using microarrays. Moreover, we used quantitative real-time PCR (qRT-PCR) to verify the genes showing differential expression levels. Furthermore, we measured the lifespan of loss-of-function mutants to determine the genes related to AGO-mediated longevity. RESULTS: AGO extended the lifespan of C. elegans, reduced lipofuscin accumulation, and maintained vigorous locomotion. The microarray analysis revealed that the endoplasmic reticulum-unfolded protein response (ER-UPR) and insulin/insulin-like growth factor-1-mediated signaling (IIS) pathway were activated in AGO-fed worms. The qRT-PCR analysis showed that AGO treatment suppressed sir-2.1 expression, which is a negative regulator of ER-UPR. In loss-of-function mutant of sir-2.1, AGO-induced longevity and heat stress resistance were decreased or cancelled completely. Furthermore, the pro-longevity effect of AGO was decreased in loss-of-function mutants of abnormal Dauer formation (daf) -2 and daf-16, which are IIS pathway-related genes. CONCLUSION: AGO delays the C. elegans aging process and extends their lifespan through the activations of ER-UPR and the IIS pathway.

Effect of concomitant use of G-CSF and myelosuppressive chemotherapy on bone marrow and peripheral granulocytes in a mouse model.

Granulocyte-colony stimulating factor (G-CSF) stimulates bone marrow progenitor cell proliferation and enhances neutrophil production. Exogenous G-CSF administration is indicated for chemotherapy-induced neutropenia management. However, there is a paucity of basic research examining the effects of the concomitant use of G-CSF and chemotherapy on myeloid cells in vivo. Whether concomitant G-CSF and chemotherapy adversely affect myeloid cell proliferation have not been determined. Herein, we examined the effects of the concomitant use of pegfilgrastim and 5-fluorouracil on myeloid cells and peripheral blood cells in mouse models. Balb/c mice were treated intraperitoneally with 5-fluorouracil (20 µg/g b.w.) or a vehicle as a control for 5 days, and pegfilgrastim was administered subcutaneously at 1 µg/g b.w. on day 3. As a result, we demonstrated that the concomitant use of pegfilgrastim suppressed the 5-fluorouracil-induced decrease of granulocytic cells in both bone marrow and peripheral blood in mice. To assess the clinical efficacy of early administration of pegfilgrastim during docetaxel, cisplatin, and 5-fluorouracil therapy in patients with esophageal cancer, we retrospectively identified 42 consecutive patients treated with this regimen. The incidence of both febrile neutropenia and grade 4 neutropenia was significantly lower in patients who received pegfilgrastim than in those who did not receive it (P = 0.002 and P = 0.002, respectively). These results suggest that the concomitant use of pegfilgrastim and chemotherapy, consisting of continuous infusions of 5-fluorouracil, improved chemotherapy-induced neutropenia without detrimental effects on proliferating myeloid granulocytic cells.

Gut Microbiota Associated with Clinical Relapse in Patients with Quiescent Ulcerative Colitis.

The microbiota associated with relapse in patients with quiescent ulcerative colitis (qUC) remains unclear. Our objective was to analyze the fecal microbiota of Japanese patients with qUC and identify the relapse-associated microbiota. In this study, 59 patients with qUC and 59 healthy controls (HCs) were enrolled (UMIN 000019486), and their fecal microbiota was compared using 16S rRNA gene amplicon sequencing. We followed their clinical course up to 3.5 years and analyzed the relapse-associated microbiota. Potential functional changes in the fecal microbiota were evaluated using PICRUSt software and the Kyoto Encyclopedia of Genes and Genomes database. There were significant differences in fecal microbiota diversity between HC and qUC subjects, with 13 taxa characterizing each subject. Despite no significant difference in variation of microbiota in a single sample (α diversity) between patients in sustained remission and relapsed patients, the variation in microbial communities between samples (ß diversity) was significantly different. Prevotella was more abundant in the sustained remission patients, whereas Faecalibacterium and Bifidobacterium were more abundant in the relapsed patients. We clustered the entire cohort into four clusters, and Kaplan-Meier analysis revealed the subsequent clinical course of each cluster was different. We identified 48 metabolic pathways associated with each cluster using linear discriminant analysis effect size. We confirmed the difference in microbiota between patients with qUC and HCs and identified three genera associated with relapse. We found that the clusters based on these genera had different subsequent clinical courses and activated different metabolic pathways.

Investigation on the Inhibitory Effect of Wnt-5a on Colonic Mucosal Inflammation in Patients with Ulcerative Colitis.

BACKGROUND: Recent progress in ulcerative colitis (UC) treatment has been remarkable, and various medications have been applied. However, some patients with UC are refractory to treatment and convert to surgery. AIM: To investigate the role of colonic mucosal Wnt-5a expression in the pathogenesis of UC and the effect of bioactive Wnt-5a peptide on colitis in mice. METHODS: Wnt-5a peptide was intraperitoneally administered to mice every day from the beginning of dextran sulfate sodium (DSS) treatment. The severity of colitis was evaluated based on body weight change, colonic length, and histological scores. Colonic mucosal TNF-α and KC mRNA expression levels were measured. This study included 70 patients with UC in clinical remission. Wnt-5a, TNFα, and IL-8 mRNA expression in the rectal mucosa were measured by quantitative real-time polymerase chain reaction using biopsy materials. Wnt-5a mRNA expression levels were compared between patients who relapsed and those in remission. We examined the correlation of Wnt-5a expression with TNF-α and IL-8 expression. RESULTS: Wnt-5a peptide significantly attenuated the severity of DSS-induced colitis. Moreover, mucosal TNF-α and KC mRNA expression were significantly suppressed by Wnt-5a peptide treatment. Wnt-5a mRNA levels were significantly lower in patients with subsequent relapse than in those who remained in remission. Mucosal Wnt-5a was inversely correlated with TNF α and IL-8 expression. CONCLUSION: Wnt-5a peptide suppressed colitis in mice, and decreased Wnt-5a expression was strongly associated with relapse in patients with UC. Wnt-5a may have an inhibitory effect on mucosal inflammation in UC, and Wnt-5a peptide could be a new therapeutic strategy.

Typing of the Gut Microbiota Community in Japanese Subjects.

Gut microbiota are involved in both host health and disease and can be stratified based on bacteriological composition. However, gut microbiota clustering data are limited for Asians. In this study, fecal microbiota of 1803 Japanese subjects, including 283 healthy individuals, were analyzed by 16S rRNA sequencing and clustered using two models. The association of various diseases with each community type was also assessed. Five and fifteen communities were identified using partitioning around medoids (PAM) and the Dirichlet multinominal mixtures model, respectively. Bacteria exhibiting characteristically high abundance among the PAM-identified types were of the family Ruminococcaceae (Type A) and genera Bacteroides, Blautia, and Faecalibacterium (Type B); Bacteroides, Fusobacterium, and Proteus (Type C); and Bifidobacterium (Type D), and Prevotella (Type E). The most noteworthy community found in the Japanese subjects was the Bifidobacterium-rich community. The odds ratio based on type E, which had the largest population of healthy subjects, revealed that other types (especially types A, C, and D) were highly associated with various diseases, including inflammatory bowel disease, functional gastrointestinal disorder, and lifestyle-related diseases. Gut microbiota community typing reproducibly identified organisms that may represent enterotypes peculiar to Japanese individuals and that are partly different from those of indivuals from Western countries.