Nobuhiko Fukuba

Pathogenesis of Irritable Bowel Syndrome - Review Regarding Associated Infection and Immune Activation

There is increasing evidence regarding the role of immune activation in the etiology of irritable bowel syndrome (IBS), which has been mainly been shown in studies investigating mechanisms of postinfectious IBS (PI-IBS). Exposure to intestinal infection induces persistent low-grade systemic and mucosal inflammation, which is characterized by an altered population of circulating cells, mucosal infiltration of immune cells and increased production of various cytokines in IBS patients. Recent studies have also indicated an increased innate immune response in these patients by evaluating expression and activation of Toll-like receptors (TLRs). These findings suggest that immune activation may play a crucial role in the pathogenesis of IBS. In addition, psychological stress has been reported to be one of the factors that induces immune activation. However, it remains unknown whether immune activation in IBS patients is largely dependent on infectious gastroenteritis and/or psychological stress. Additional studies are necessary to understand the precise mechanism of immune activation and its relationship to the development of IBS.

Role of regulatory B cells in chronic intestinal inflammation: association with pathogenesis of Crohn's disease.

Abstract:The role of regulatory B cells (Bregs) producing interleukin (IL)-10 in the pathogenesis of inflammatory bowel diseases remains unknown. We investigated IL-10 production in B cells from patients with inflammatory bowel diseases and immunoregulatory functions of Bregs in experimental colitis mouse models. CpG DNA-induced IL-10 production in peripheral blood B cells isolated from patients with inflammatory bowel diseases and control subjects was examined. CD19 and CD1d were used for evaluating possible cell surface markers of Bregs. Colitis models of severe combined immunodeficiency mice were established by adoptive transfer of whole CD4+ T cells or regulatory T cell (Treg)-depleted T cells (CD4+CD25−) isolated from SAMP1/Yit mice and the function of Bregs in intestinal inflammation was elucidated by evaluating the effects of cotransfer of whole or Breg-depleted B cells. CpG DNA-induced IL-10 production was significantly decreased in B cells from patients with Crohns disease (CD), as compared with those from healthy controls, whereas Bregs were found to be enriched in a population of CD19hi and CD1dhi B cells isolated from both human and mouse samples. The severity of intestinal inflammation was significantly increased in the Breg-depleted mice, with similar results also found in adoptive transfer colitis model mice even after Treg depletion. Our findings show that Bregs, characterized by the cell surface markers CD19hi and CD1dhi, significantly reduced experimental colitis regardless of the presence or absence of Tregs. These results suggest that a deficiency or decrease of Bregs function exacerbates intestinal inflammation, which may be associated with the pathogenesis of CD.

Prevalence of irritable bowel syndrome-like symptoms in ulcerative colitis patients with clinical and endoscopic evidence of remission : prospective multicenter study

Abstract Objective. Irritable bowel syndrome (IBS)-like symptoms are often found in ulcerative colitis (UC) patients in remission. However, the prevalence of those symptoms in UC patients with endoscopic evidence of remission shown by mucosal healing remains unknown. Material and methods. IBS diagnosis was evaluated by questionnaire results according to the Rome III criteria. Clinical remission was assessed by clinical activity index (CAI), whereas endoscopic remission was evaluated by endoscopic index (Matts grade). Results. We enrolled 172 patients in clinical remission (CAI ≤ 4), after excluding 36 for incomplete questionnaire results or nonremission findings, as well as 330 control subjects. Of the 172 UC patients, 46 (26.7%) met the Rome III criteria, which was a significantly higher rate as compared with the controls (4.8%). The prevalence rate of IBS-like symptoms in UC patients with endoscopic remission findings (Matts grade ≤2) was 25.6%, which was similar to that of those with clinical remission. When endoscopic remission was defined as Matts grade 1, the prevalence rate of IBS-like symptoms was decreased to 15.4%, although the prevalence rate remained higher than that of the control subjects. Conclusions. The prevalence of IBS-like symptoms in UC patients with clinical and endoscopic remission findings was significantly higher than that of control subjects. Furthermore, the prevalence rate in patients with complete endoscopic remission was decreased. These findings suggest that residual low-grade inflammation may influence the presence of IBS-like symptoms in UC patients in remission.

Fecal Calprotectin More Accurately Predicts Endoscopic Remission of Crohnʼs Disease than Serological Biomarkers Evaluated Using Balloon-assisted Enteroscopy

Background: Fecal calprotectin (FC) has emerged as a reliable surrogate marker of endoscopic remission in Crohns disease (CD), which has been mainly evaluated using ileocolonoscopy. We conducted this study to clarify the predictability of FC level for predicting endoscopic remission using balloon-assisted enteroscopy (BAE) findings in patients with CD and compare with that of conventional serological biomarkers. Methods: Patients with CD scheduled to undergo BAE were prospectively enrolled, and fecal and blood samples collected before the procedures. We used a modified simple endoscopic score for CD, in which the parameter “presence of narrowing” was removed from conventional simple endoscopic score for CD. Endoscopic remission was defined as modified simple endoscopic score for CD 0 to 2. Results: Seventy BAE procedures were performed in 53 patients with CD and evaluated. The area under the curve in receiver operating characteristic curve analysis of FC to predict endoscopic remission was 0.93, with an optimal cut-off value of 252.9 &mgr;g/g, and 96% sensitivity and 83% specificity, which was higher than that for C-reactive protein, albumin, white blood cell count, and platelet count (0.76, 0.66, 0.39, and 0.65, respectively). The area under the curve of FC for predicting endoscopic remission was high in patients with ileal and ileocolonic disease location (0.86 and 0.96, cut-off values 204.2 and 253.7 &mgr;g/g, respectively), and also higher than the area under the curve values of serological markers. Conclusions: BAE findings showed that FC was more accurate for predicting endoscopic remission in CD than C-reactive protein, albumin, white blood cell count, and platelet count. Even in small-bowel CD, FC may be a more reliable surrogate marker of endoscopic remission than serological biomarkers.

Fecal calprotectin level correlated with both endoscopic severity and disease extent in ulcerative colitis

BackgroundThe relationship between fecal calprotectin (FC) and disease extent in ulcerative colitis (UC) has not been fully elucidated. The aim of this study was to clarify the correlation of FC with disease extent and severity in UC patients.MethodsUC patients scheduled to undergo an ileocolonoscopy were enrolled and fecal samples for FC measurement were collected prior to the procedure. A Mayo endoscopic subscore (MES) was determined for each of 5 colonic segments. To evaluate the association of FC with extent of affected mucosa as well as disease severity, we assessed the correlation of FC level with the sum of MES (S-MES) for the 5 colonic segments as compared to the maximum score of MES (M-MES).ResultsFC measurements in conjunction with findings from 136 complete colonoscopies in 102 UC patients were evaluated. FC level showed a stronger correlation with S-MES (correlation coefficient r = 0.86, p < 0.001) as compared to M-MES (r = 0.79, p < 0.001). In patients with an M-MES of 1, 2, and 3, FC level showed a significant correlation with S-MES (r = 0.67, p < 0.001; r = 0.70, p < 0.001; r = 0.47, p = 0.04, respectively). Our findings indicate that FC level is elevated in patients with greater areas of affected mucosa even in those with the same M-MES value.ConclusionsFC level was shown to be correlated with the extent of affected mucosa as well as severity in UC patients, thus it is useful for precise assessment of mucosal inflammation.

Role of milk fat globule-epidermal growth factor 8 in colonic inflammation and carcinogenesis

BackgroundMilk fat globule-epidermal growth factor 8 (MFG-E8) promotes phagocytic clearance of apoptotic cells to maintain normal tissue homeostasis. However, its functions in intestinal inflammation and carcinogenesis are unknown.MethodsExperimental colitis was induced in MFG-E8 knockout (KO) and wild-type (WT) mice by dextran sodium sulfate (DSS) administration. Colon tissues were used for assessments of colitis activity and epithelial proliferation. A mouse colitis-associated cancer (CAC) model was induced by intraperitoneal injection of azoxymethane (AOM) and then the animals were given a single administration of DSS. A sporadic colon cancer model was established by repeated intraperitoneal injections of AOM. The role of MFG-E8 in epithelial proliferation with or without treatment of siRNA targeting αv-integrin was examined in vitro using a WST-1 assay.ResultsThe severity of colitis in KO mice was greater than that in WT mice, while the proliferative potential of colonic epithelial cells in KO mice was lower during the regenerative phase. In both CAC and sporadic models, tumor size in KO was lower as compared to WT mice, while decreased tumor incidence was only found in the CAC model. In vitro findings showed that MFG-E8 promotes epithelial cell proliferation, and treatment with a siRNA targeting αv-integrin reduced the proliferation of Colon-26 cells stimulated with recombinant MFG-E8.ConclusionsMFG-E8 promotes tumor growth regardless of the presence or absence of colonic inflammation, whereas colon tumor development is initiated by MFG-E8 under inflammatory conditions. These MFG-E8 functions may be dependent on integrin-mediated cellular signaling.

Complete response of a pancreatic adenosquamous carcinoma to chemoradiotherapy

A 51-year-old woman with an unresectable pancreatic tumor that was histologically diagnosed as an adenosquamous carcinoma underwent chemoradiotherapy with 5-fluourouracil (FU) and low-dose cisplatin (low-dose FP). Because we recognized a partial response to the chemoradiotherapy, we subsequently administered combined chemotherapy with S-1 and cisplatin. After one course of this combined chemotherapy, the tumor was further reduced in size and became difficult to discern on abdominal computed tomography (CT). We have continued to administer the S-1 and cisplatin combined chemotherapy, and the patient is still alive. After 20 months of treatment, the tumor has not recurred (as assessed by abdominal CT). Additionally, we have not seen elevation of tumor markers. This report presents the successful use of chemoradiotherapy with low-dose FP and additional combined chemotherapy with S-1 and cisplatin for unresectable pancreatic adenosquamous carcinoma.

Downregulation of serotonin reuptake transporter gene expression in healing colonic mucosa in presence of remaining low-grade inflammation in ulcerative colitis.

The serotonin reuptake transporter (SERT) terminates serotonin activity by removing it from interstitial space. Downregulated colonic SERT expression has been reported in irritable bowel disease (IBS), and symptoms resembling IBS occur in cases of inflammatory bowel disease (IBD) in remission; thus, a common pathogenesis for IBS and IBD is possible. However, little is known regarding SERT expression in colonic mucosa of IBD patients during healing.

Crosstalk between TLR5 and Notch1 signaling in epithelial cells during intestinal inflammation.

During intestinal inflammation, a variety of signaling events are activated to perform several cell functions. Although the distinct roles of these pathways have been elucidated, the effects of their crosstalk activities remain to be clarified. We evaluated the crosstalk between two evolutionary conserved cell signaling systems, toll-like-receptor (TLR) 5 and Notch1, in intestinal epithelial cells during inflammation. Significant induction of the expression of Notch1 and Jagged1 was observed in the distal part of the colon, together with abundant localization of Notch1 intracellular domain (N1ICD) in the surface epithelium of inflamed colonic mucosa. By targeting intestinal epithelial cells, it was shown that recombination-signal-binding-protein-Jκ (RBP-Jκ)-mediated Notch functions are dependent on a flagellin-TLR5-mediated pathway. Conversely, using a γ-secretase inhibitor, we demonstrated that Notch synergistically increases TLR5‑mediated NF-κB activation. In addition, the effects of Notch on the NF-κB target gene interleukin-6 (IL-6) expression were revealed by evaluating the RBP-Jκ responsive element in the IL-6 promoter in vitro. Modulation of TLR5 and Notch crosstalk by transient blocking of Notch during the acute phase of colitis was beneficial for ameliorating colonic inflammation as well as disease status. In conclusion, the results suggest the effectiveness of Notch-targeted drug strategy for the treatment of intestinal inflammation.

Esophageal triamcinolone acetonide–filling method: a novel procedure to prevent stenosis after extensive esophageal endoscopic submucosal dissection (with videos)

BACKGROUND AND AIMS Endoscopic submucosal dissection (ESD) for extensive esophageal carcinomas may cause severe stenosis requiring endoscopic balloon dilations (EBDs). A standard prevention method has not been established. We propose the esophageal triamcinolone acetonide (TA)-filling method as a novel local steroid administration procedure. METHODS We enrolled 22 consecutive patients with early esophageal cancer who were treated using either subcircumferential or circumferential ESD (15 and 7 procedures, respectively) in this case series. Esophageal TA filling was performed on the day after ESD and 1 week later and was performed again if mild stenosis was found on follow-up. EBD with TA filling was performed only for severe stenosis that prevented endoscope passage. The primary endpoint was the incidence of severe stenosis. Secondary endpoints were the total number of EBDs and additional TA filling, dysphagia score, time to stenosis and to complete re-epithelialization, and any adverse events. RESULTS The incidence of severe stenosis was 4.5% (1/22; confidence interval, .1%-22.8%), and EBD was performed 2 times in 1 patient. Mild stenosis was found in 9 patients. Additional TA filling was performed in 45.5% of patients (10/22; median, 5 times; range, 1-13). The dysphagia score deteriorated to 1 to 2 in 31.8% (7/22) but showed a final score of 0 after complete re-epithelialization in 90.9% (20/22). The median time to stenosis was 3 weeks (range, 3-4) and that to complete re-epithelialization was 7 weeks (range, 4-36). No severe adverse events occurred. CONCLUSIONS The esophageal TA-filling method is highly effective for preventing severe stenosis after extensive esophageal ESD.