Immunomodulators and immunosuppressants for Japanese patients with ulcerative colitis

Ulcerative colitis (UC) is characterized by a long-standing chronic course with remissions and exacerbations. Previously, patients do not respond to 5-aminosalicylic acid compounds and corticosteroids are considered for colectomies, however, in recent years, alternative treatments emerged for steroid-refractory or steroid-dependent UC. In this review article, we focus on immunomodulators (such as azathioprine [AZA] and 6-mercaptopurine [6-MP]) and immunosuppressants (such as cyclosporine A [CSA] and tacrolimus [FK506]) for steroid-refractory or steroid-dependent ulcerative colitis. The characteristics, efficacy and adverse effects of these drugs are outlined. Although the randomized trial of FK506 is conducted in Japan, the clinical data of CSA in Japanese patients are limited. The short-, mid- and long-term follow-ups of CSA administration in Japanese patients are discussed. As for thipurine drugs, the clinical importance of multidrug-resistance protein 4 (MRP4) in Japanese patients is highlighted.

Dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) recognizes a novel ligand, Mac-2-binding protein, characteristically expressed on human colorectal carcinomas

Dendritic cell (DC)-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) is a type II transmembrane C-type lectin expressed on DCs such as myeloid DCs and monocyte-derived DCs (MoDCs). Recently, we have reported that DC-SIGN interacts with carcinoembryonic antigen (CEA) expressed on colorectal carcinoma cells. CEA is one of the most widely used tumor markers for gastrointestinal cancers such as colorectal cancer. On the other hand, other groups have reported that the level of Mac-2-binding protein (Mac-2BP) increases in patients with pancreatic, breast, and lung cancers, virus infections such as human immunodeficiency virus and hepatitis C virus, and autoimmune diseases. Here, we first identified Mac-2BP expressed on several colorectal carcinoma cell lines as a novel DC-SIGN ligand through affinity chromatography and mass spectrometry. Interestingly, we found that DC-SIGN selectively recognizes Mac-2BP derived from some colorectal carcinomas but not from the other ones. Furthermore, we found that the α1-3,4-fucose moieties of Le glycans expressed on DC-SIGN-binding Mac-2BP were important for recognition. DC-SIGN-dependent cellular interactions between immature MoDCs and colorectal carcinoma cells significantly inhibited MoDC functional maturation, suggesting that Mac-2BP may provide a tolerogenic microenvironment for colorectal carcinoma cells through DC-SIGN-dependent recognition. Importantly, Mac-2BP was detected as a predominant DC-SIGN ligand expressed on some primary colorectal cancer tissues from certain parts of patients in comparison with CEA from other parts, suggesting that DC-SIGN-binding Mac-2BP bearing tumor-associated Le glycans may become a novel potential colorectal cancer biomarker for some patients instead of CEA.

Comparison of the fecal microbiota profiles between ulcerative colitis and Crohn's disease using terminal restriction fragment length polymorphism analysis

BACKGROUND

Terminal restriction fragment length polymorphism (T-RFLP) analysis is a powerful tool to assess the diversity of a microbial community. In this study, we performed T-RFLP analysis of the fecal microbiota from patients with ulcerative colitis (UC) and those with Crohn's disease (CD).

METHODS

Thirty-one patients with UC, 31 patients with CD, and 30 healthy individuals were enrolled. The polymerase chain reaction (PCR) products obtained from the 16S rRNA genes of fecal samples were digested with BslI, and T-RF lengths were determined.

RESULTS

The fecal microbial communities were classified into 5 clusters. Twenty-eight of the 30 healthy individuals and 17 of the 18 patients with inactive UC were classified into clusters I, II, and III, but these clusters included a small number of patients with active UC and inactive/active CD. In contrast, 8 of the 13 patients with active UC and the majority of CD patients (12 of the 16 patients with inactive CD, and 11 of the 15 patients with active CD) were included in clusters IV and V. Based on the BslI-digested T-RFLP database, the bacteria showed a significant decrease in the Clostridium family in patients with active UC and inactive/active CD. In contrast, Bacteroides were significantly increased in CD patients. No significant differences were observed between patients with active UC and those with active CD.

CONCLUSION

The fecal microbial communities of IBD patients were different from those of healthy individuals. The gut microbiota of patients with inactive UC tended to be closer to that of healthy individuals, suggesting different roles for the fecal microbiota in the pathophysiology of UC and CD.

The DPP-IV inhibitor ER-319711 has a proliferative effect on the colonic epithelium and a minimal effect in the amelioration of colitis

Dipeptidyl-peptidase IV (DPP-IV) inhibitors are expected to prolong the half-life of Glucagon-like peptide (GLP-2) as well as GLP-1, and may result in the promotion of epithelial cell proliferation and regeneration. The aim of this study was to investigate whether a DPP-IV inhibitor can promote epithelial proliferation and attenuate dextran sodium sulfate (DSS)-induced colitis. Nine-week-old female C57/B6 mice were given a single dose of ER-319711 to assess the changes in plasma GLP-2 concentrations. Ten mice were divided into two groups: a vehicle group and an ER-319711 group. ER-319711 was administered orally for 7 days. The mice were then given bromodeoxyuridine (BrdU) intraperitoneally 2 h before sacrifice on day 7. Twenty-six mice were divided into three groups: a vehicle group, a DSS-induced colitis group and a DSS-induced colitis treated with ER-319711 group. The mice were given DSS for 5 days and sacrificed on day 14. Plasma GLP-2 levels were elevated in response to ER-319711. The ER-319711 group had a significantly decreased body weight from days 1 to 3. The number of BrdU positive cells per crypt and the crypt height were increased in the ER-319711 group. The DSS + ER-319711 group had a decreased body weight transition. The disease activity index and colon length showed an amelioration of colitis in the DSS + ER-319711 group. DPP-IV inhibitors are thought to promote the proliferation of the intestinal epithelium. However, the amelioration of DSS-induced colitis was only partial.

A new isoform of interleukin-32 suppresses IL-8 mRNA expression in the intestinal epithelial cell line HT-29

Interleukin (IL)-32 plays a role in the pathophysiology of inflammatory bowel disease (IBD). We isolated a new isoform of the IL-32 transcript in the process of cloning the full-length IL-32 gene from human colonic subepithelial myofibroblasts (SEMFs). The expression of mRNA in the samples was assessed by RT-PCR and real-time PCR analyses. The PCR products from the IL-32 genes were ligated into the expression vector pIRESneo2. The new isoform of the IL-32 transcript (336 nucleotides) completely lacked exon 4 of the IL-32γ gene, and was 60 bp shorter than IL-32α. TNF-α induced the mRNA expression of the new IL-32 isoform in a dose- and time-dependent manner. Stable transfection of this new isoform significantly decreased TNF-α-induced IL-8 mRNA expression in HT-29 cells, but the expression of the IL-32α gene had no effect. The mRNA expression of this new isoform was significantly elevated in the inflamed mucosa of IBD patients. A new isoform of the IL-32 transcript may play an anti-inflammatory role in the inflamed mucosa of IBD.

Increased apoptosis and decreased proliferation of colonic epithelium in dextran sulfate sodium-induced colitis in mice

The pathogenic mechanisms responsible for inflammatory bowel disease, especially ulcerative colitis (UC), are poorly understood. In animal models, the oral administration of dextran sulfate sodium (DSS) induces colitis, which exhibits several clinical and histological features similar to UC. In addition, the longstanding administration of DSS also induces colon cancer. However, the pathogenic factors responsible for DSS-induced colitis and the subsequent colon cancer also remain unclear. In particular, there are only limited data concerning colonic epithelia cell apoptosis and proliferation in DSS-induced colitis. Therefore, we investigated the relationships between these factors. Colitis was induced in BALB/cA Jcl mice by 8 days of oral administration of standard diets containing 5% (w/w of diet) DSS. The control mice received the standard diets only. Morphological changes in the colonic mucosa were evaluated and scored by light microscopy. Apoptosis was studied by the TUNEL assay, and cell proliferation by Ki-67 immunoreactivity. The macroscopic findings showed the most severe inflammation in the distal colon. Epithelial apoptosis increased approximately 5-fold after DSS administration as compared to the controls. On the other hand, the mitotic cells decreased about half-fold as compared to the controls. Ki-67 immunohistochemistry showed that cells with cell cycle arrest at the G0 stage in the crypt increased approximately 2-fold as compared to the controls. In conclusion, the increased apoptosis and decreased proliferation might lead to a breakdown of the epithelial barrier function, and thus facilitate the mucosal invasion of intraluminal microorganisms in DSS-induced colitis.

New prebiotics from rice bran ameliorate inflammation in murine colitis models through the modulation of intestinal homeostasis and the mucosal immune system

BACKGROUND

Enzyme-treated rice fiber (ERF) is a recently developed prebiotic product made from rice bran by heat-resistant amylase, protease and hemicellulase treatment. Although the detailed mechanism of inflammatory bowel disease (IBD) is still unclear, the role of the resident luminal bacteria and its interaction on the mucosal barrier seem to be an important factor in the development of IBD and its chronicity. With the objective of manipulating the intestinal microbiota in IBD, this study was carried out to evaluate the effects of ERF on IBD with using experimental colitis models.

METHODS

Three colitis models were used and they were induced by the oral administration of dextran sodium sulfate in male Sprague-Dawley rats or BALB/c mice and transferring CD4+ CD45RB(high) T cells to female SCID mice, sequentially their CD4+ T cells were retransferred to new SCID mice. The evaluation included the measurement of body weight, spleen weight, colon length, histological examination, serum and mucosal cytokine (tumor necrosis factor-alpha (TNF-α), an interferon-gamma (IFN-γ), interleukin-12 p70 (IL-12p70), IL-1β, IL-6, IL-4) analysis, mucosal serotonin (5HT), and organic acid production and a microbiota analysis of the cecal contents. The characteristics of T cell surface markers including CD4, CD69, CD45RB of spleen and mesenteric lymph nodes (MLN) were also analyzed. In addition, the effects of ERF on the change in the induction of dendritic cells (DCs) were evaluated.

RESULTS

The preventive effect of ERF on colitis was significantly superior to that of raw material rice bran or control group. An overexpression of inflammatory cytokine production was attenuated by ERF treatment, which was accompanied with a decrease in both the colonic mucosal damage and 5HT production. Furthermore, ERF significantly attenuated the T cell activation (CD4+CD69+) of spleen and MLN, and this characteristic was inherited by the retransferred mice. ERF significantly suppressed the growth of Clostiridium, and increased short-chain fatty acids (acetate, propionate and butyrate) content in colitis. The relatively hydrophilic fraction of ERF (ethanol-methanol soluble fraction) is therefore considered to have a potent ability to attenuate the induction of DCs.

CONCLUSION

A new prebiotic, ERF, reduced inflammation by modulating the colonic environment and regulating immune cell differentiation. Although a more detailed study is required, this study showed the promising anti-inflammatory effects of an adjunctive prebiotic treatment for IBD.

Interleukin-32α expression in human colonic subepithelial myofibroblasts

Interleukin (IL)-32 is a recently described proinflammatory cytokine, characterized by induction of nuclear factor (NF)-κB activation. We studied IL-32α expression in human colonic subepithelial myofibroblasts (SEMFs). Colonic SEMFs were isolated from normal human colon tissue. IL-32α protein expression was evaluated by Western blot analyses, and IL-32α mRNA expression was analyzed by real-time PCR. IL-32α mRNA was weakly expressed without a stimulus, and its expression was markedly enhanced by IL-1ß and TNF-α. IL-1ß and TNF-α enhanced intracellular accumulation of IL-32α protein, but IL-32α was not detected in supernatants. Each cytokine dose- and time-dependently induced IL-32α mRNA expression. An inhibitor of phosphatidylinositol 3-kinase (LY294002) significantly suppressed IL-1ß- and TNF-α-induced IL-32α mRNA expression, although MAPK inhibitors had no effect. Akt activation in response to these cytokines was confirmed by Western blotting. Blockade of NF-κB activation by an adenovirus expressing a stable mutant form of IκBα markedly suppressed IL-1ß- and TNF-α-induced IL-32α mRNA expression. Human colonic SEMFs expressed IL-32α in response to IL-1ß and TNF-α. IL-32α mRNA expression depends on the phosphatidylinositol 3-kinase and the NF-κB system.

Hepatic reactive lymphoid hyperplasia in a patient with primary biliary cirrhosis

Reactive lymphoid hyperplasia (RLH) of the liver is an extremely rare lesion characterized by the proliferation of non-neoplastic lymphocytes forming follicles. Hepatic RLH is known to be associated with gastrointestinal carcinoma and autoimmune diseases including primary biliary cirrhosis (PBC). We report a case of hepatic RLH in a patient with PBC and gastric cancer. A 68 year old Japanese woman with a 10 year history of liver enzyme abnormality was admitted. Laboratory testing revealed that her anti-mitochondrial antibody was markedly elevated. Five mo after the diagnosis of PBC, she was found to have gastric cancer. Abdominal computed tomography disclosed a liver nodule in S8, suggesting metastatic gastric carcinoma. Histopathologically, the resected liver lesion comprised of a nodular proliferation of small lymphocytes with lymphoid follicles. This is the first reported case of hepatic RLH in a patient with both PBC and gastric cancer. Pre-operative diagnosis of hepatic RLH by clinical imaging is extremely difficult. Therefore, a needle biopsy could be useful to make a diagnosis of hepatic RLH, especially to differentiate from metastatic gastrointestinal carcinoma.

Interleukin-33 expression is specifically enhanced in inflamed mucosa of ulcerative colitis

BACKGROUND

Interleukin (IL)-33 is a cytokine belonging to the IL-1 family. IL-33 has been shown to elicit a Th2-like cytokine response in immune cells. In this study, we investigated IL-33 expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD), and characterized the molecular mechanisms responsible for IL-33 expression in human colonic subepithelial myofibroblasts (SEMFs).

METHODS

IL-33 mRNA expression was determined by real-time polymerase chain reaction (PCR). IL-33 expression in the IBD mucosa was evaluated by immunohistochemical methods.

RESULTS

IL-33 mRNA expression was significantly elevated in active lesions from patients with ulcerative colitis (UC), but was not detected in inactive lesions from UC patients or in lesions from patients with either active or inactive Crohn's disease. Colonic SEMFs were identified as a major source of IL-33 in the mucosa. IL-1β and tumor necrosis factor-α (TNF-α) significantly enhanced IL-33 mRNA and protein expression in isolated colonic SEMFs. IL-1β and TNF-α did not affect IL-33 expression in intestinal epithelial cell lines (HT-29 and Caco-2 cells). This IL-1β- and TNF-α-induced IL-33 mRNA expression was mediated by p42/44 mitogen activated protein kinase (MAPK) pathway-dependent activation of nuclear factor (NF)-κB and activator protein (AP)-1.

CONCLUSIONS

IL-33, derived from colonic SEMFs, may play an important role in the pathophysiology of UC.

Pneumatosis coli with ulcerative colitis as a rare complication of colonoscopy

Pneumatosis coli is a relatively rare condition characterized by the presence of gas in the submucosa or subserosa involving mainly the large intestine and, occasionally, the mesenteric attachments. We experienced two cases of pneumatosis coli with ulcerative colitis after colonoscopy that had different clinical courses. Case 1 showed submucosal pneumatosis coli and portal venous air. The air was resolved 30 h later. Case 2 showed subserosal pneumatosis coli and retropneumoperitoneum. The air was eliminated after 3 weeks. The clinical features of pneumatosis coli may depend on the intramural region of the air. Cases 1 and 2 had different air localization, that is, submucosal and subserosal air, and this seems to reflect the differences in the complications. In Case 1 the air expanded to the portal vein, and took only a short time to resolve. In Case 2, however, the air leaked to the retroperitoneal space and took a long time to resolve. In summary, pneumatosis coli as a complication of colonoscopy presented different features depending on the air location. To our knowledge, this is the first report to reveal the difference of air localization and the complications associated with pneumatosis coli after colonoscopy.

Hepatocellular carcinoma occurring in a Crohn’s disease patient

We report a case of hepatocellular carcinoma (HCC) occurring in a patient with Crohn’s disease (CD) without chronic hepatitis or liver cirrhosis, and review the clinicopathological features of HCC in CD patients. A 37-year-old Japanese man with an 8-year history of CD and a medication history of azathioprine underwent resection of a liver tumor. The histopathology of the liver tumor was pseudoglandular type HCC. In the non-neoplastic liver, focal hepatocyte glycogenosis (FHG) was observed, however, there was no evidence of liver cirrhosis or primary sclerosing cholangitis. Only nine cases of HCC in CD patients have been reported previously in the English-language literature. Eight of 10 cases (including the present case) had received azathioprine treatment, and four of these cases also showed FHG, which is considered a preneoplastic liver lesion, within the non-neoplastic liver. Although the precise mechanism of the development of HCC in CD patients is controversial, these results suggest that azathioprine therapy and FHG in the non-neoplastic liver contribute to the development of HCC. These findings also indicate that it is important to survey CD patients treated with prolonged azathioprine therapy for potential liver tumors.

Microsatellite instability with promoter methylation and silencing of hMLH1 can regionally occur during progression of gastric carcinoma

Microsatellite instability (MSI) is known to result from inactivation of mismatch repair genes largely by promoter methylation. However, the methylation usually accumulates time-dependently. To know whether MSI can be acquired later in tumorigenesis, we examined intratumoral heterogeneity of MSI and promoter methylation of hMLH1 after immunohistochemical screening for heterogeneous expression of hMLH1 in 55 cases of gastric carcinomas. We demonstrated for the first time that MSI-H can develop from MSI-L or the absence of MSI due to time-dependent accumulation of DNA methylation during progression of early-stage gastric carcinomas. The resultant replication errors may play a role in enhancing invasive activity.

Butyrate stimulates IL-32α expression in human intestinal epithelial cell lines

AIM: To investigate the effects of butyrate on interleukin (IL)-32α expression in epithelial cell lines.

METHODS: The human intestinal epithelial cell lines HT-29, SW480, and T84 were used. Intracellular IL-32α was determined by Western blotting analyses. IL-32α mRNA expression was analyzed by real-time polymerase chain reaction.

RESULTS: Acetate and propionate had no effects on IL-32α mRNA expression. Butyrate significantly enhanced IL-32α expression in all cell lines. Butyrate also up-regulated IL-1β-induced IL-32α mRNA expression. Butyrate did not modulate the activation of phosphatidylinositol 3-kinase (PI3K), a mediator of IL-32α expression. Like butyrate, trichostatin A, a histone deacetylase inhibitor, also enhanced IL-1β-induced IL-32α mRNA expression.

CONCLUSION: Butyrate stimulated IL-32α expression in epithelial cell lines. An epigenetic mechanism, such as histone hyperacetylation, might be involved in the action of butyrate on IL-32α expression.

Spectra of functional gastrointestinal disorders diagnosed by Rome III integrative questionnaire in a Japanese outpatient office and the impact of overlapping

BACKGROUND AND AIMS

The aim of this study was to establish the spectra of functional gastrointestinal disorders (FGID) in a Japanese outpatient office in Rome III.

METHODS

The Rome III Diagnostic Questionnaire for Adult Functional GI Disorders was translated into Japanese and an automated analyzing program was made according to the scoring algorithm of the questionnaire. Among 1378 patients who visited the outpatient office of the Social Insurance Shiga Hospital between May 2007 and April 2009, 112 serial patients who had symptoms possibly originating from the gastrointestinal (GI) tract, but did not have evidence of organic disease, were recruited. The subjects answered the questionnaire, and the answers were analyzed with the automatic analyzer.

RESULTS

During the study period, 94 of the 112 patients were diagnosed as having active FGID. Non-overlapping FGID was diagnosed in 41 (43.6%) of those. Of the 41 non-overlapping FGID patients, the most frequent diagnosis was irritable bowel syndrome (IBS) in 13 patients. Including overlapping cases, 165 FGID were diagnosed in 94 patients. The most frequent diagnosis was IBS in 33 patients (35.1%), the second was functional dyspepsia (FD) in 29 (30.9%) and the third was functional constipation in 21 (22.3%). The most frequent FGID overlapping with IBS was FD (36.4%), and the most frequent FGID overlapping with FD was IBS (41.4%). Of the 29 FD patients, 20 (69.0%) had functional bowel disorders.

CONCLUSION

The most frequent FGID was IBS in both overlapping and non-overlapping FGID patients. IBS and FD were the most frequent combinations in overlapping FGID. Most cases of FD are possibly parts of functional bowel disorders.

Energy expenditure in Japanese patients with severe or moderate ulcerative colitis

We investigated the energy expenditure in hospitalized patients with severe or moderate ulcerative colitis (UC), and compared them to healthy controls. Thirteen patients (5 women and 8 men; mean age 31.8 years; mean BMI 19.0 kg/m²) and 10 healthy volunteers were enrolled in this study. The resting energy expenditure (mREE) levels were determined by indirect calorimetry. The mREEs of the UC patients were significantly higher than those of healthy controls (26.4 ± 3.6 vs 21.8 ± 1.7 kcal/kg/day), although the mREEs of the UC patients were almost the same as the predicted REEs (pREEs) calculated by the Harris-Benedict equation (26.4 ± 2.4 kcal/kg/day vs 26.5 ± 2.6 kcal/kg/day). The mREE/pREE ratio, which reflects stress, was 1.0 ± 0.15. In the UC patients, a significant correlation was observed between the mREEs and the clinical activity index. In conclusion, UC patients showed a hyper-metabolic status as evaluated by their mREE/body weight. Energy expenditure was significantly correlated with disease activity. From our observations, we recommend that nutritional management with more than 30–35 kcal/ideal body weight/day (calculated by the mREE × activity factor) may be optimal for active severe or moderate ulcerative colitis.

Expression of interleukin 1-like cytokine interleukin 33 and its receptor complex (ST2L and IL1RAcP) in human pancreatic myofibroblasts

OBJECTIVE

Interleukin 33 (IL33) is a cytokine belonging to the IL1 family and it binds to a complex of the ST2L/IL1 receptor accessory protein (IL1RAcP). To define the role of IL33 in fibrogenesis of the pancreas, the expression of IL33, ST2L and IL1RAcP was examined in chronic pancreatitis tissues. The effects of IL33 on the functions of human pancreatic myofibroblasts were also investigated.

METHODS

Tissue samples were obtained surgically. The expression of IL33, ST2L and IL1RAcP was evaluated by standard immunohistochemical procedures. Messenger RNA expression for IL33, ST2L and IL1RAcP was analysed by northern blotting and real-time PCR analyses, and protein expression was assessed by western blotting and ELISA. Cell proliferation and migration were assessed by a (3)H-thymidine incorporation assay and the modified Boyden chamber assay, respectively.

RESULTS

IL33, ST2L and IL1RAcP were expressed by alpha-SMA-positive myofibroblasts in the fibrosis of chronic pancreatitis. In human pancreatic myofibroblasts, IL33 was weakly immunoexpressed without any stimuli, and this was markedly enhanced by IL1beta, tumour necrosis factor alpha (TNFalpha) and lipopolysaccharide (LPS) via the mitogen-activated protein kinase (MAPK)-dependent AP-1 activation pathway. ST2L mRNA was weakly detected in unstimulated cells, and IL4 and interferon gamma (IFNgamma) strongly enhanced ST2L expression via STAT6 and STAT1 signalling, respectively. IL33 rapidly induced the phosphorylation of MAPKs and IkappaBalpha, and enhanced the expression of inflammatory mediators (IL6, IL8, IP-10, Gro-alpha, Gro-beta and MCP-1) in IL4- or IFNgamma-pretreated cells. IL33 stimulated the proliferation and migration of pancreatic myofibroblasts.

CONCLUSIONS

IL33 and its receptor complex (ST2L and IL1RAcP) constitute a novel signalling system which may play an important role in the pathogenesis of chronic pancreatitis.

Factors affecting the efficacy of cyclosporin A therapy for refractory ulcerative colitis

BACKGROUND AND AIMS

Cyclosporin A (CSA), an immunosuppressive agent, is highly efficacious in patients with refractory ulcerative colitis (UC). We retrospectively investigated patients with refractory UC treated with CSA therapy to elucidate the efficacy and the prognostic factors.

METHODS

Forty-one patients (26 men and 15 women) were enrolled. The efficacy of CSA was assessed at three time points: short- and mid-term assessments took place 2 weeks and 1 year after CSA administration, respectively, and long-term assessments at the end of the observation period.

RESULTS

The short-term response rate was 71%. Background analysis revealed risk factors for CSA unresponsiveness: (i) more than 10,000 mg of prednisolone used before CSA treatment; (ii) the presence of circulating (C7-HRP); and (iii) disease duration more than 4 years. The mid-term relapse-free survival rate was 51.0%. The addition of azathioprine (AZA) after CSA treatment significantly suppressed the incidence of relapse at 1 year (72.5% vs 26.7%, P = 0.0237). The overall colectomy-free survival rate was 46.4%, and the induction of AZA after CSA treatment significantly reduced the colectomy rate (66.7% vs 30.5%, P = 0.0419). Among CSA responders, AZA naïve patients had significant lower-probabilities for colectomies compared to patients with prior AZA treatment (22.5% vs 56.7%, P = 0.0309). The administration of CSA was discontinued in five cases.

CONCLUSION

Our results revealed factors affecting the efficacy of CSA therapy for patients with refractory UC. AZA is an important agent that maintains disease quiescence once one responds to CSA. However, refractory patients despite AZA treatment are more likely to have consequent colectomies.

OmpA variants affecting the adherence of ulcerative colitis-derived Bacteroides vulgatus

To investigate the adhesion factor of Bacteroides vulgatus derived from ulcerative colitis (UC), we isolated B. vulgatus strains from the large intestinal mucosa of UC patients and non-UC individuals, and examined their adherence to tissue-cultured cells. The adherence to tissue-cultured cells in UC-derived strains (36.5 +/- 7.9 %) was higher than that in non-UC-derived strains (13.2 +/- 7.7 %). PCR and sequencing analysis of outer membrane proteins revealed that the strains derived from five of seven (71.4 %) UC patients had ompA genes belonging to either ompA variant type A or B. The adherence rates in Escherichia coli DH5 a transformants with ompA type A variants (33.3 +/- 4.6 %) and type B variants (34.6 +/- 7.1 %) were higher than the rate in those with non-UC ompA (16.4 +/- 4.0 %). Our results suggest that B. vulgatus isolates in the mucosal flora of the large intestine of UC patients have a high frequency of ompA variants and that the variation of ompA variants is one of the factor causing an increase in the adherence of the bacterium.

Cellobiose Prevents the Development of Dextran Sulfate Sodium (DSS)-Induced Experimental Colitis

Cellobiose is produced from cellulose using specific bacterial enzymes, and is hydrolyzed into glucose by the enzymes cellobiosidase and cellulase. In this study, we examined the effects of cellobiose on colonic mucosal damage in a dextran sulfate sodium (DSS) colitis model. BALB/c mice were divided into two groups. In the first group, the mice were fed 3.5% DSS mixed with normal chow. In the second group, the mice were fed 3.5% DSS plus 6.0 or 9.0% (weight/weight) cellobiose mixed with normal chow. The development of colitis was assessed on day 21. Mucosal cytokine expression was analyzed by RT-PCR. Body weight loss was significantly attenuated in the 9.0% cellobiose-fed DSS mice as compared to the DSS mice. Colonic weight/length ratio, a maker of tissue edema, was significantly higher in the DSS mice than in the 9.0% cellobiose-fed DSS mice. The disease activity index and histological colitis score were also significantly higher in the DSS mice than in the 9.0% cellobiose-fed DSS mice. Mucosal mRNA expression for IL-1β, TNF-α, IL-17 and IP-10 were markedly reduced in the 9.0% cellobiose-fed DSS mice. In conclusion, a preventive effect of cellobiose against DSS colitis suggests its clinical use for inflammatory bowel diseases patients.

Proteus mirabilis sp. intestinal microflora grow in a dextran sulfate sodium-rich environment

The pathogenic mechanisms responsible for inflammatory bowel disease, especially ulcerative colitis (UC), are poorly understood. As an animal model, the oral administration of dextran sulfate sodium (DSS) induces colitis, which exhibits several clinical and histological features similar to UC. However, the pathogenic factors responsible for DSS-induced colitis and above all, the intestinal microflora in this colitis remain unclear. Therefore, we investigated the relationships between DSS and the intestinal microflora in this study. First, the depolymerization of DSS in mouse feces was analyzed using a pyridylamino-labeling (PA-DSS) and HPLC system. Next, a bacteriological study of the fecal contents using DSS-rich media and subsequently a classification using 16S rRNA were performed. Surprisingly, DSS was depolymerized in mouse feces under aerobic conditions, not under anaerobic conditions. Several kinds of microflora were suggested to be involved in this depolymerization. In particular, Proteus mirabilis can grow in DSS-rich media and has an ability to desulfonate and depolymerize DSS. Then, we produced chemically-modified Mr 2500 DSS from native Mr 5000 DSS. This depolymerized Mr 2500 DSS was administered orally to mice and the colitis was evaluated histologically. The cytotoxicity of Mr 2500 DSS on Caco-2 cells was also investigated. Mr 2500 DSS induced weaker colitis in mice and weak cytotoxicity on Caco-2 cells as compared to Mr 5000 DSS. These findings give insight into the mechanisms responsible for DSS-induced colitis, especially with respect to the molecular mass of DSS.