Recent steroid use and the relapse risk in ulcerative colitis patients with endoscopic healing.

BACKGROUND: Endoscopic healing (EH) is a therapeutic target in ulcerative colitis (UC). However, even patients who have achieved EH relapse frequently. AIMS: To investigate the association between recent steroid use and relapse risk in UC patients with EH. METHODS: This multi-centre cohort study included 1212 UC patients with confirmed EH (Mayo endoscopic subscore ≤1). We excluded patients with current systemic steroid use or history of advanced therapy. We divided patients into a recent steroid group (last systemic steroid use within 1 year; n = 59) and a non-recent or steroid-naïve group (n = 1153). We followed the patients for 2 years to evaluate relapse, defined as induction of systemic steroids or advanced therapy. We used logistic regression to estimate the odds ratio (OR) of relapse. RESULTS: Relapse occurred in 28.8% of the recent steroid group and 5.6% of the non-recent/steroid-naïve group (multi-variable-adjusted OR 5.53 [95% CI 2.85-10.7]). The risk of relapse decreased with time since the last steroid use: 28.8% for less than 1 year after steroid therapy, 22.9% for 1 year, 16.0% for 2 years and 7.9% beyond 3 years, approaching 4.0% in steroid-naïve patients. (ptrend <0.001). CONCLUSIONS: Even for patients with UC who achieved EH, the risk of relapse remains high following recent steroid therapy. Physicians need to consider the duration since last steroid use to stratify the relapse risk in UC patients with EH.

Endoscopic healing is associated with a reduced risk of biologic treatment failure in patients with ulcerative colitis.

Increasing number of patients with ulcerative colitis (UC) have received biologic treatment during the last decade. The association between endoscopic healing (EH) and biologic treatment failure remains understudied. Medical information of UC patients who started biologic treatment was retrospectively collected. EH was defined as Mayo endoscopic subscore of 0 or 1. Loss of response (LOR)-free drug continuation rate was compared between patients who achieved EH and those who did not using Kaplan-Meier estimator. Fifty-two patients received 53 biologic treatments and underwent follow-up colonoscopies within 2 years. Thirty-three patients achieved EH, all of which remained on the same treatment without LOR during the observational period. Twenty patients did not achieve EH, 8 of which ultimately discontinued the treatment due to LOR to biologic agents. Kaplan-Meier estimator found a significantly lower drug continuation rate in patients without EH (p < 0.001; log-rank test). A Cox regression analysis identified EH as an independent factor associated with a reduced risk of LOR-related biologic treatment failure irrespective of the types of biologic agents (Hazard Ratio = 0.0324, p < 0.001). EH within 2 years is associated with a reduced risk of LOR-related biologic treatment failure in patients with UC.

Bowel frequency (night) and urgent defecation are improved by budesonide foam in patients with ulcerative colitis: a retrospective observational study.

INTRODUCTION: Patients with ulcerative colitis (UC) are known to have a significantly poor quality of life due to bowel frequency (night) and urgent defecation. Budesonide foam is a topical medication that was approved in Japan in 2017 for the treatment of UC. However, its efficacy in the treatment of bowel frequency (night) or urgent defecation is unknown. This study aimed to explore the efficacy of budesonide foam for the alleviation of these symptoms. METHODS: UC patients who received budesonide foam between December 2017 and January 2020 at the Jikei University School of Medicine in Tokyo were enrolled. The simple clinical colitis activity index (SCCAI) was evaluated at the start of budesonide foam treatment and 2 and 6 weeks later in patients who initially scored ≥ 1 for bowel frequency (night) and urgent defecation, respectively. We also studied the effect of budesonide foam on remaining symptoms in patients who had used 5-aminosalicylic acid (5-ASA) topical treatment, those with SCCAI ≥ 3, and those in remission with residual symptoms (SCCAI 1 or 2). RESULTS: Of the 233 enrolled patients, 102 were eligible for the study. In 36 patients with bowel frequency (night) treated with budesonide foam were significantly effective, score in SCCAI decreased from 1.17 ± 0.45 at baseline to 0.53 ± 0.61 at week 2 (p < 0.0001) and 0.17 ± 0.38 at week 6 (p < 0.0001). In 45 patients with urgent defecation score in SCCAI decreased significantly from 1.33 ± 0.52 at baseline to 0.44 ± 0.59 at week 2 (p < 0.0001) and 0.22 ± 0.40 at week 6 (p < 0.0001). Of 22 patients who switched from topical 5-ASA administration to budesonide foam, nine at week 2 (41%) and 11 (50%) at week 6 were improved with no symptoms, and there were no cases of worsened symptoms. No severe side effects associated with budesonide foam were observed. CONCLUSION: Budesonide foam administration significantly improves both bowel frequency (night) and urgent defecation-related UC activity and is also effective for the patients who were refractory to topical 5-ASA administration.

Characteristics and Endoscopic Classification of Ulcerative Lesions Affecting the Ileocecal Valve.

OBJECTIVES: The aim of this study was to propose an endoscopic classification system for ulcerative lesions on the ileocecal valve and investigate its relevance to the underlying etiology. METHODS: Among the 60,325 patients who underwent colonoscopy at our hospital from January 2006 to December 2018, patients with ulcerative lesions on the ileocecal valve were included. The following data were obtained using the hospital's medical records: sex, age, clinical diagnosis, laboratory data, and endoscopic and histological findings. Patients who have ulcerative colitis and who were not evaluated by histological examination were excluded. Ulcerative lesions on the ileocecal valve were classified into 3 groups according to their endoscopic appearance: small shallow ulcerative lesions without edematous change (group A), lateral spreading shallow ulcerative lesions with edematous change (group B), and deep deformed ulcerative lesions (group C). The association between this endoscopic classification and its clinical diagnosis, clinical course, and the interobserver reliability were evaluated. RESULTS: Of 72 patients who were eligible for analysis, 18 were assigned to group A, 9 to group B, and 45 to group C. Infectious enteritis was mainly assigned to group A (group A, 12; group B, none; and group C, 6; p < 0.0001), inflammatory bowel disease was mainly assigned to group C (group A, none; group B, 5; and group C, 35; p < 0.0001), and malignant tumor was assigned to group C only. Interobserver reliability was extremely high among the 3 examining doctors (kappa value 0.7-0.8). CONCLUSION: Endoscopic classification was divided into 3 groups for ulcerative lesions on the ileocecal valve, and this system could be beneficial for presuming their clinical diagnoses.

Protective Effect of Luminal Uric Acid Against Indomethacin-Induced Enteropathy: Role of Antioxidant Effect and Gut Microbiota.

BACKGROUND: Uric acid (UA) has anti- and pro-inflammatory properties. We previously revealed that elevated serum UA levels provide protection against murine small intestinal injury probably via luminal UA secreted in the small intestine. Luminal UA may act as an antioxidant, preventing microbiota vulnerability to oxidative stress. However, whether luminal UA is increased under hyperuricemia and plays a protective role in a dose-dependent manner as well as the mechanism by which luminal UA exerts its protective effects on enteropathy remains unknown. METHODS: Inosinic acid (IMP) (1000 mg/kg, i.p.) was administered to obtain high serum UA (HUA) and moderate serum UA (500 mg/kg IMP, i.p.) mice. UA concentrations and levels of oxidative stress markers in the serum and intestine were measured. Mice received indomethacin (20 mg/kg, i.p.) to evaluate the effects of UA on indomethacin-induced enteropathy. Reactive oxygen species (ROS) on the ileal mucosa were analyzed. The fecal microbiota of HUA mice was transplanted to investigate its effect on indomethacin-induced enteropathy. RESULTS: IMP increased luminal UA dose-dependently, with higher levels of luminal antioxidant markers. Indomethacin-induced enteropathy was significantly ameliorated in both UA-elevated groups, with decreased indomethacin-induced luminal ROS. The microbiota of HUA mice showed a significant increase in α-diversity and a significant difference in ß-diversity from the control. Fecal microbiota transplantation from HUA mice ameliorated indomethacin-induced enteropathy. CONCLUSIONS: The protective role of luminal UA in intestinal injury is likely exerted via oxidative stress elimination and microbiota composition modulation, preferably for gut immunity. Therefore, enhancing anaerobic conditions using antioxidants is a potential therapeutic target.

Novel probiotic yeast from Miso promotes regulatory dendritic cell IL-10 production and attenuates DSS-induced colitis in mice.

BACKGROUND: Yeasts are a type of fungi thought to have probiotic functions. In this study, we isolated a novel probiotic yeast (Zygosaccharomyces sapae strain I-6) from Miso (a traditional Japanese fermented food). We examined its effects on phenotypic changes in intestinal dendritic cells (DCs), and evaluated its anti-inflammatory effects in dextran sulfate sodium (DSS)-induced colitis. METHODS: A single colony was selected from homogenized Miso, based on its ability to produce interleukin (IL)-10 in CD11c+ bone marrow DCs (BMDCs) in vitro. The anti-inflammatory effects of strain I-6 on CD11c+ BMDCs and CD11c+ CD103+ DCs were analyzed in mouse mesenteric lymph nodes in vitro and in a DSS mouse model. RESULTS: The IL-10 concentrations in the co-culture BMDC supernatants treated with I-6 were dramatically higher than in those treated with Saccharomyces cerevisiae (Sc). IL-10 production is mediated by both TLR2 and Dectin-1. ß-Glucan extracted from I-6 also induced higher levels of IL-10 production in BMDCs than ß-glucan from Sc. The number of mesenteric lymph node CD11c+ CD103+ DCs was significantly increased by I-6 administration, compared with Sc administration. Strain I-6 showed strong anti-inflammatory effects on DSS-induced colitis compared to Sc. Moreover, the adoptive transfer of I-6-treated BMDCs showed anti-inflammatory effects on DSS-induced colitis in mice without oral administration of I-6 cells. CONCLUSIONS: Strain I-6 induced phenotypic changes in intestinal CD11c+ DCs characterized by high IL-10 production and exerted strong anti-inflammatory effects on DSS-induced colitis. Traditional Japanese fermented foods may be a valuable source of probiotic yeasts for effective IBD therapy and treatment.

Deoxycholic acid enhancement of lymphocyte migration through direct interaction with the intestinal vascular endothelium.

BACKGROUND AND AIM: The small intestine plays a central role in gut immunity, and enhanced lymphocyte migration is involved in the pathophysiology of various enteropathy. Bile acid (BA) is closely related to lipid metabolism and gut microbiota and essential for gut homeostasis. However, the effects of BA on gut immunity have not been studied in detail, especially on the small intestine and lymphocyte migration. Therefore, we aimed to investigate the effect of BA on small intestinal lymphocyte microcirculation. METHODS: The effect of deoxycholic acid (DCA), taurocholic acid (tCA), or cholic acid (CA) on the indomethacin (IND)-induced small intestinal enteropathy in mice was investigated. Lymphocyte movements were evaluated after exposure to BA using intravital microscopy. The effects of BA on surface expression of adhesion molecules on the vascular endothelium and lymphocytes through BA receptors were examined in vitro. RESULTS: IND-induced small intestinal enteropathy was histologically aggravated by DCA treatment alone. The expression of adhesion molecules ICAM-1 and VCAM-1 was significantly enhanced by DCA. Exposure to DCA increased lymphocyte adhesion in the microvessels of the ileum, which was partially blocked by anti-α4ß1 integrin antibody in vivo. The expression of ICAM-1 and VCAM-1 was significantly enhanced by DCA in vitro, which was partially suppressed by the sphingosine-1-phosphate receptor 2 (S1PR2) antagonist. The S1PR2 antagonist significantly ameliorated IND-induced and DCA-exaggerated small intestinal injury. CONCLUSION: DCA exacerbated IND-induced small intestinal enteropathy. DCA directly acts on the vascular endothelium and enhances the expression levels of adhesion molecules partially via S1PR2, leading to enhanced small intestinal lymphocyte migration.

Intestinal inflammations increase efflux of innate lymphoid cells from the intestinal mucosa to the mesenteric lymph nodes through lymph-collecting ducts.

INTRODUCTION: Innate lymphoid cells (ILCs) are abundant in the intestinal mucosa, forming boundaries externally. Herein, ILCs were directly obtained from intestinal lymph using a lymph fistula rat model and analyzed under physiological and pathological conditions. METHODS: Thoracic duct (TD) lymphocytes were collected by cannulation with/without preceded mesenteric lymphadenectomy, which were comparable to lymphocytes flowing through mesenteric lymphatic vessels (MLVs) or TD, respectively. The collected ILCs were classified according to gene transcription factors and analyzed by flow cytometry. The effect of IL-25 or indomethacin was studied. RESULTS: The proportion of total ILCs in the MLVs (MLV-ILCs) was significantly higher than that in TD (TD-ILCs, 0.01% vs. 0.003%, respectively). Physiologically, there were several significant differences in the MLV-ILCs compared with TD-ILCs, including the proportion of ILC2 (42.3% vs. 70.9%) and ILC3 (33.3% vs. 13.8%), and the proportion of α4-integrin-positive cells (36.8% vs. 0.3%). IL-25 significantly increased the proportion of MLV-ILC2 after 3 days. Indomethacin-induced intestinal injury increased the proportion of MLV-ILC3 in the early phase within 12 h. CONCLUSION: Intestinal ILCs were found to migrate through MLVs. The altered mobilization of MLV-ILCs after stimuli suggests that ILCs play an important role in regulating the immune responses at the secondary lymph nodes.

Microscopic Observation of Lymphocyte Dynamics in Rat Peyer's Patches.

Naïve lymphocytes recirculate from the blood to the lymphoid tissues under physiological condition and it is commonly recognized as an important phenomenon in the gut immunity. The stroma of secondary lymphoid organs, such as Peyer's patches (PPs) or mesenteric lymph nodes, are where naïve lymphocytes sense antigens. Naïve lymphocytes circulate through the bloodstream to reach high endothelial venules, the portal of entry into PPs. Some immunomodulators are estimated to influence lymphocyte migration, but the precise evaluation of microcirculation dynamics is very difficult, and establishing a method to observe lymphocyte migration in vivo can contribute to the clarification of the precise mechanisms. We refined the method of collecting lymphocytes from the lymph duct and observing the detailed dynamics of gut-tropic lymphocytes in rat PPs. We chose confocal laser scanning microscopy to observe rat PPs in vivo and recorded it using time-lapse photography. We can now obtain clear images that can contribute to the analysis of lymphocyte dynamics.

MicroRNA-93 targets WASF3 and functions as a metastasis suppressor in breast cancer.

Cancer cells with cancer stem cell (CSC) properties initiate both primary tumor formation and metastases at distant sites. Acquisition of CSC properties is highly associated with epigenetic alterations, including those mediated by microRNAs (miRNAs). We have previously established the breast cancer patient-derived tumor xenograft (PDX) mouse model in which CSC marker CD44+ cancer cells formed spontaneous microscopic metastases in the liver. In this PDX mouse, we found that the expression levels of 3 miRNAs (miR-25, miR-93, and miR-106b) in the miR-106b-25 cluster were much lower in the CD44+ human cancer cells metastasized to the liver than those at the primary site. Constitutive overexpression of miR-93 suppressed invasive ability and 3D-organoid formation capacity of breast cancer cells in vitro and significantly suppressed their metastatic ability to the liver in vivo. Wiskott-Aldrich syndrome protein family member 3 (WASF3), a regulator of both cytoskeleton remodeling and CSC properties, was identified as a functional target of miR-93: overexpression of miR-93 reduced the protein level of WASF3 in breast cancer cells and WASF3 rescued the miR-93-mediated suppression of breast cancer cell invasion. These findings suggest that miR-93 functions as a metastasis suppressor by suppressing both invasion ability and CSC properties in breast cancers.

Clinical Significance of Intraoperative Colonoscopy for Anastomotic Assessment in Rectal Cancer Surgery.

BACKGROUND/AIM: To clarify the usefulness of intraoperative colonoscopy (CS) for preventing postoperative anastomotic leakage and bleeding in rectal cancer surgery. PATIENTS AND METHODS: The data of rectal cancer patients who underwent circular-stapled anastomosis from January 2008 to December 2016 were compared between 162 patients who received intraoperative CS (the CS group) and 23 patients who did not receive intraoperative CS (the non-CS group). RESULTS: Anastomotic leakage rate in the CS group (8.6%) was similar to that in the non-CS group (4.3%) (p=0.70). Postoperative anastomotic bleeding rate was also similar between the CS and non-CS groups (2.4% vs. 0%, p=0.50). Although a positive air leak test was observed in two patients in the CS group, no postoperative leakage developed by adding intraoperative treatment. CONCLUSION: Although intraoperative CS did not significantly reduce the incidence of postoperative anastomotic leakage or bleeding, it can be useful for certain cases.

Lipoprotein Lipase Up-regulation in Hepatic Stellate Cells Exacerbates Liver Fibrosis in Nonalcoholic Steatohepatitis in Mice.

Lipoprotein lipase (LPL) plays a central role in incorporating plasma lipids into tissues and regulates lipid metabolism and energy balance in the human body. Conversely, LPL expression is almost absent in normal adult livers. Therefore, its physiological role in the liver remains unknown. We aimed to elucidate the role of LPL in the pathophysiology of nonalcoholic steatohepatitis (NASH), a hepatic manifestation of obesity. Hepatic stellate cell (HSC)-specific LPL-knockout (LplHSC-KO ) mice, LPL-floxed (Lplfl/fl ) mice, or double-mutant toll-like receptor 4-deficient (Tlr4-/- ) LplHSC-KO mice were fed a high-fat/high-cholesterol diet for 4 weeks to establish the nonalcoholic fatty liver model or an high-fat/high-cholesterol diet for 24 weeks to establish the NASH model. Human samples, derived from patients with nonalcoholic fatty liver disease, were also examined. In human and mouse NASH livers, serum obesity-related factors, such as free fatty acid, leptin, and interleukin-6, dramatically increased the expression of LPL, specifically in HSCs through signal transducer and activator of transcription 3 signaling, as opposed to that in hepatocytes or hepatic macrophages. In the NASH mouse model, liver fibrosis was significantly reduced in LplHSC-KO mice compared with that in Lplfl/fl mice. Nonenzymatic LPL-mediated cholesterol uptake from serum lipoproteins enhanced the accumulation of free cholesterol in HSCs, which amplified TLR4 signaling, resulting in the activation of HSCs and progression of hepatic fibrosis in NASH. Conclusion: The present study reveals the pathophysiological role of LPL in the liver, and furthermore, clarifies the pathophysiology in which obesity, as a background factor, exacerbates NASH. The LPL-mediated HSC activation pathway could be a promising therapeutic target for treating liver fibrosis in NASH.

Chitinase 3-like 1 deficiency ameliorates liver fibrosis by promoting hepatic macrophage apoptosis.

AIM: Chitinase 3-like 1 (CHI3L1), an 18-glycosyl hydrolase-related molecule, is a member of the enzymatically inactive chitinase-like protein family. Serum levels of CHI3L1 are strongly correlated with hepatic fibrosis progression during many liver diseases. Therefore, this protein could be involved in the development of hepatic fibrosis pathology; however, its role has not been elucidated. We aimed to elucidate its role in the pathophysiology of liver fibrosis. METHODS: Chitinase 3-like 1-deficient (Chi3l1-/- ) mice were given carbon tetrachloride twice per week for 4 weeks or fed a methionine choline-deficient diet for 12 weeks to generate mouse liver fibrosis models. Human fibrotic liver tissues were also examined immunohistochemically. RESULTS: In human and mouse fibrotic livers, CHI3L1 expression was mainly localized to hepatic macrophages, and the intrahepatic accumulation of CHI3L1+ macrophages was significantly enhanced compared to that in control livers. In the two mouse models, hepatic fibrosis was significantly ameliorated in Chi3l1-/- mice compared to that in wild-type mice, which was dependent on hepatic macrophages. The accumulation and activation of hepatic macrophages was also significantly suppressed in Chi3l1-/- mice compared to that in wild-type mice. Furthermore, apoptotic hepatic macrophages were significantly increased in Chi3l1-/- mice. Chitinase 3-like 1 was found to inhibit hepatic macrophage apoptosis by suppressing Fas expression and activating Akt signaling in an autocrine manner, which resulted in hepatic macrophage accumulation and activation, exaggerating liver fibrosis. CONCLUSIONS: Chitinase 3-like 1 exacerbates liver fibrosis progression by suppressing apoptosis in hepatic macrophages. Therefore, this might be a potential therapeutic target for the treatment of liver fibrosis.

Depression Promotes the Onset of Irritable Bowel Syndrome through Unique Dysbiosis in Rats.

Background/Aims: Although studies using conventional animal models have shown that specific stressors cause irritable bowel syndrome (IBS), it is unclear whether depression itself causes IBS. Our aim was to establish a rat model to determine if depression itself promotes the onset of IBS and to elucidate the role of gut microbiota in brain-gut axis pathogenesis during coincident depression and IBS. Methods: Rat models of depression were induced using our shuttle box method of learned helplessness. Visceral hypersensitivity was evaluated by colorectal distension (CRD) to diagnose IBS. Gut microbiota compositions were analyzed using high-throughput sequencing. In the subanalysis of rats without depression-like symptoms, rats with posttraumatic stress disorder (PTSD) were also examined. Results: The threshold value of CRD in depressed rats was significantly lower than that in control rats. Microbial community analysis of cecal microbiota showed that the relative abundance of Clostridiales incertae sedis, the most prevalent microbe, was significantly lower in depressed rats than in control rats. The distribution pattern of the microbiota clearly differed between depressed rats and control rats. Neither visceral hypersensitivity nor the composition of gut microbiota was altered in rats with PTSD-like phenotypes. Conclusions: Our rat model of depression is useful for clarifying the effect of depression on IBS and suggests that depression itself, rather than specific stressors, promotes the onset of IBS. Further, we provided evidence that various psychiatric diseases, viz., depression and PTSD, are associated with unique gut microbiota profiles, which could differentially affect the onset and progression of coincident IBS.

Discordance of MCM7 mRNA and its Intronic MicroRNA Levels Under Hypoxia.

BACKGROUND: Intronic microRNAs (miRNAs) are considered to be transcribed using their host gene promoter. However, about one third of intronic miRNAs are predicted to have independent promoter elements. MATERIALS AND METHODS: Human breast cancer cells were cultured under normoxia or hypoxia, and expression levels of intronic miR-106b-25 cluster miRNAs and their host gene minichromosome maintenance complex component 7 (MCM7) transcripts were analyzed by semi-quantitative polymerase chain reaction. The putative promoter element of miR-106b-25 cluster was analyzed by chromatin immunoprecipitation and luciferase assays. RESULTS: Exposure to hypoxia reduced the expression of MCM7 mRNA and a primary transcript of miR-106b-25 cluster, but did not affect that of mature miRNAs. The putative promoter element of miR-106b-25 cluster was not bound by hypoxia-inducible factor 1-alpha (HIF1-α), and was not activated under hypoxia. CONCLUSION: Maintenance of miR-106b-25 cluster miRNA levels under hypoxia was not caused by the activation of an independent promoter element.

Splenic Marginal Zone Lymphoma with Acquired von Willebrand Syndrome Diagnosed via Splenic Bleeding.

An 85-year-old woman underwent emergent splenectomy due to left abdominal pain and active bleeding in a massively enlarged spleen. The histological diagnosis was splenic marginal zone lymphoma (SMZL). A prolonged activated partial thromboplastin time (APTT) was noted, and additional tests led to the diagnosis of type 2A-like acquired von Willebrand syndrome (AVWS). An APTT cross mixing test ruled out the presence of inhibitors. She received eight courses of rituximab monotherapy. The coagulation data showed no improvement, possibly because the lymphoma showed a poor response to the treatment. AVWS rarely causes bleeding in solid organs. This is the first case of SMZL with AVWS diagnosed via splenic bleeding.

Proteomic characterization of the site-dependent functional difference in the rat small intestine.

To investigate the site-dependent functional difference in the small intestine, proteomic analysis was carried out on the three distinct parts of the rat small intestine. Male Wistar rats (7 weeks old) were fed a semi-purified diet ad libitum for 1 week. Intestinal tissues from the proximal, middle and distal regions of the small intestine were subjected to two-dimensional polyacrylamide gel electrophoresis, and the abundance of each spot was determined fluorometrically. MALDI-TOF/MS and LC-MS/MS analysis of the tryptic peptides were performed to identify the proteins. Many of the 180 identified proteins showed a distinctive distribution pattern along the small intestine. Glutathione S-transferase, Catechol O-methyltransferase and Villin 2 decreased gradually from the jejunum to the ileum, in contrast, non-specific dipeptidase and Keratin 19 increased gradually toward the ileum. The voltage-dependent anion channel 2 was most abundant in the duodenum while the L- and I-Fatty acid binding protein (FABP) and Cellular retinol binding protein (CRBP-II) were in the jejunum, and the Bile acid binding protein (BABP) was only observed in the ileum. The findings of these and of another proteins identified in this study may contribute to further understanding of the small intestinal function, and to clinical applications of small intestinal diseases.