Evolving paradigms in the pathogenesis of IBD

Immunosuppressive monocytes: possible homeostatic mechanism to restrain chronic intestinal inflammation

Chronic colitis is accompanied by extensive myelopoiesis and accumulation of CD11b+Gr-1+ cells in spleens and secondary lymphoid tissues. Although cells with similar phenotype have been described in cancer, chronic infection, or autoimmunity, where they were associated with suppression of T cell responses, little is known regarding how these cells affect CD4 T cell responses in the context of chronic intestinal inflammation. Therefore, we undertook this study to characterize the interplay between colitis-induced myeloid cells and CD4 T cell. Within the CD11b+Gr-1+ population, only monocytes (Ly6G(neg)Ly6C(high)) but not other myeloid cell subsets suppressed proliferation and production of cytokines by CD4 T cells. Suppression was mediated by cell-contact, NO and partially by IFN-γ and PGs. Interestingly, Ly6C(high) MDCs, isolated from colitic colons, showed up-regulation of iNOS and arginase-1 and were more potent suppressors than those isolated from spleen. On a single-cell level, MDCs inhibited Th1 responses but enhanced generation of foxp3+ T cells. MDCs, cocultured with activated/Teffs, isolated from inflamed colons under hypoxic (1% O2) conditions typical for the inflamed intestine, suppressed proliferation but not their production of proinflammatory cytokines and chemokines. Taken together, expansion of monocytes and MDCs and activation of their suppressive properties may represent a homeostatic mechanism aimed at restraining excessive T cell activation during chronic inflammatory settings. The contribution of immunosuppressive monocytes/MDCs to chronic colitis and their role in shaping T cell responses in vivo require further investigation.

Relationship between serum infliximab trough levels and endoscopic activities in patients with Crohn's disease under scheduled maintenance treatment

BACKGROUND AND AIMS

Few data are available to support the clinical relevance of infliximab (IFX) trough levels for prediction of endoscopic disease activity in Crohn's disease (CD). This study evaluated the endoscopic disease activities in relation to clinical outcome using several laboratory markers including serum IFX trough levels in patients with CD undergoing scheduled IFX maintenance treatment.

MATERIALS AND METHODS

A total of 78 sessions of endoscopy were performed on 45 patients with CD. Endoscopic activity was assessed using the modified Rutgeerts scoring system. IFX trough levels and anti-IFX antibodies (ATIs) were determined by immunoassays.

RESULTS

Endoscopic activity negatively correlated with serum IFX trough levels (Spearman's rank correlation coefficient (ρ) = -0.54, P < 0.0001) and serum albumin levels (ρ = -0.46, P < 0.0001), and positively correlated with CRP (C-reactive protein) levels (ρ = 0.55, P < 0.0001), ESR (erythrocyte sedimentation rate) (ρ = 0.47, P < 0.0001) and fecal calprotectin levels. IFX trough levels and serum albumin levels were significantly elevated in the mucosal healing (MH) group, but ATIs, CRP, ESR and fecal calprotectin levels were significantly elevated in the nonmucosal healing group. Receiver operation curve revealed that the optimal cutoff value of IFX trough levels for identifying normal laboratory markers was 0.6 μg/ml for CRP, 1.0 μg/ml for serum albumin and 1.1 μg/ml for fecal calprotectin. Identification of mucosal healing needed a higher cutoff value of 4.0 μg/ml. Thiopurine treatment did not affect IFX trough and ATI levels.

CONCLUSION

Mucosal healing requires higher IFX trough levels, compared to those to achieve normalization of routine clinical markers.

Characterization of gut microbiota profiles by disease activity in patients with Crohn's disease using data mining analysis of terminal restriction fragment length polymorphisms

The gut microbiota plays a significant role in the pathogenesis of Crohn’s disease (CD). In this study, we analyzed the disease activity and associated fecal microbiota profiles in 160 CD patients and 121 healthy individuals. Fecal samples from the CD patients were collected during three different clinical phases, the active (n=66), remission-achieved (n=51) and remission-maintained (n=43) phases. Terminal restriction fragment length polymorphism (T-RFLP) and data mining analysis using the Classification and Regression Tree (C&RT) approach were performed. Data mining provided a decision tree that clearly identified the various subject groups (nodes). The majority of the healthy individuals were divided into Node-5 and Node-8. Healthy subjects comprised 99% of Node-5 (91 of 92) and 84% of Node-8 (21 of 25 subjects). Node-3 was characterized by CD (136 of 160 CD subjects) and was divided into Node-6 and Node-7. Node-6 (n=103) was characterized by subjects in the active phase (n=48; 46%) and remission-achieved phase (n=39; 38%) and Node-7 was characterized by the remission-maintained phase (21 of 37 subjects; 57%). Finally, Node-6 was divided into Node-9 and Node-10. Node-9 (n=78) was characterized by subjects in the active phase (n=43; 55%) and Node-10 (n=25) was characterized by subjects in the remission-maintained phase (n=16; 64%). Differences in the gut microbiota associated with disease activity of CD patients were identified. Thus, data mining analysis appears to be an ideal tool for the characterization of the gut microbiota in inflammatory bowel disease.

Skin-induced tolerance as a new needle free therapeutic strategy

This article summarizes current knowledge about a new subject called "skin induced tolerance". Suppression is induced via epicutaneous (EC) immunization with a protein antigen and is described in Th1, Tc1 and NK mediated contact hypersensitivity (CHS) reactions. The subject of skin-induced suppression is also described in the regulation of experimental models of autoimmune diseases like experimental autoimmune encephalomyelitis (EAE), collagen induced arthritis (CIA) and inflammatory bowel disease (IBD) and finally in an animal model of graft rejection. The potential clinical use of this approach to regulate human diseases is also discussed.

Cannabis use provides symptom relief in patients with inflammatory bowel disease but is associated with worse disease prognosis in patients with Crohn's disease

BACKGROUND

Cannabinoids are used by patients with inflammatory bowel disease (IBD) to alleviate their symptoms. Little is known on patient motivation, benefit, or risks of this practice. Our aim was to assess the extent and motives for Cannabis use in patients with IBD and the beneficial and adverse effects associated with self-administration of Cannabis.

METHODS

Consecutive patients with IBD (n = 313) seen in the University of Calgary from July 2008 to March 2009 completed a structured anonymous questionnaire covering motives, pattern of use, and subjective beneficial and adverse effects associated with self-administration of Cannabis. Subjects who had used Cannabis specifically for the treatment of IBD or its symptoms were compared with those who had not. Logistic regression analysis was used to identify variables predictive of poor IBD outcomes, specifically surgery or hospitalization for IBD.

RESULTS

Cannabis had been used by 17.6% of respondents specifically to relieve symptoms associated with their IBD, the majority by inhalational route (96.4%). Patients with IBD reported that Cannabis improved abdominal pain (83.9%), abdominal cramping (76.8%), joint pain (48.2%), and diarrhea (28.6%), although side effects were frequent. The use of Cannabis for more than 6 months at any time for IBD symptoms was a strong predictor of requiring surgery in patients with Crohn's disease (odds ratio = 5.03, 95% confidence interval = 1.45-17.46) after correcting for demographic factors, tobacco smoking status, time since IBD diagnosis, and biological use. Cannabis was not a predictor for hospitalization for IBD in the previous year.

CONCLUSIONS

Cannabis use is common in patients with IBD and subjectively improved pain and diarrheal symptoms. However, Cannabis use was associated with higher risk of surgery in patients with Crohn's disease. Patients using Cannabis should be cautioned about potential harm, until clinical trials evaluate efficacy and safety.

Mycobacterium avium paratuberculosis infection augments innate immune responses following intestinal epithelial injury

We wanted to determine if augmented innate immune activation is associated with lesion development in a mycobacterial enhanced intestinal injury model. We evaluated the local immune response in a Mycobacterium avium paratuberculosis + dextran sulfate sodium (Map + DSS) model using BALB/c and severe combined immunodeficient (SCID) mice. Map + DSS BALB/c and SCID mice displayed a similar disease phenotype. Moreover, Map + DSS SCID mice had increased expression of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), inducible nitric oxide synthase (iNOS) and increased numbers of F4/80 positive cells. Additionally, Map antigen is co-localized with iNOS and IL-1β positive cells. This suggests that subclinical Map infection promotes innate immune activation following injury to the intestinal epithelium.

Manganese superoxide dismutase plays an important role in the inflammatory process and predicts disease severity and activity in patients with ulcerative colitis

The aim of this study was to investigate the expression pattern of manganese superoxide dismutase (MnSOD) in relation to inflammatory factors in ulcerative colitis (UC) and characterize this enzyme as a newly identified biomarker potentially linked to disease pathogenesis of UC. MnSOD expression was analyzed immunohistochemically in 48 formalin-fixed and paraffin-embedded specimens from patients with UC who had undergone endoscopical biopsy. MnSOD expression was observed in vascular endothelium, macrophages, and polymorphonuclear leukocytes within lamina propria of inflamed mucosa. The patients who did not express MnSOD tended to have stabilization of symptoms, but accompanied with status of inflammation. The MnSOD expression pattern was strongly correlated with disease type. MnSOD was expressed in polymorphonuclear leukocytes of all disease types, but cases of chronically counting and exacerbation type had particularly high frequency of immunopositive cells. MnSOD expression in macrophages was frequently observed in cases of symptom remaining type. The cases with MnSOD expression in the vascular endothelium showed a tendency to express in relapse-remission and exacerbation of symptoms. Immunohistochemical evaluation for MnSOD expression may be useful for predicting disease severity and activity in patients with UC.

Naïve T cells correlate with mucosal healing in patients with inflammatory bowel disease

BACKGROUND

In previous studies, adaptive immune responses involving T-helper cells have been shown to play an important role in inflammatory bowel diseases (IBDs).

METHODS

The aim of this study was to investigate any correlation between the degree of mucosal inflammation and the phenotype of gut-infiltrating T-helper cells. Biopsies from intestinal mucosa were obtained and intestinal T cells were analyzed with regard to activity and maturation markers. Patients with active colitis (39 with Crohn's disease and 47 with ulcerative colitis) were included and treated with corticosteroids, biologicals or leukocytapheresis. Flow cytometry was used to analyze activation marker expression on gut-infiltrating T-helper cells.

RESULTS

Mucosal healing was reflected by almost 100% increase of CD62L expression in mucosal T cells in patients in remission compared to those with active inflammation (p < 0.01). The frequency of mucosal-naïve CD4(+)CD45RA(+) T cells was reduced by 50% in mucosa displaying remission (5.3% compared to 12% of the total amount and CD4(+) T cells, p < 0.001). Surprisingly, the proportion of early activated T-helper cells (CD4(+)CD69(+)) did not differ between mucosa in remission and non-remission (43% and 42%, respectively). Moreover, no change in memory T-helper cells (CD4(+)CD45RO(+)) was observed (64% compared to 66%). The findings were independent of diagnosis (Crohn's disease or ulcerative colitis) or mode of treatment.

CONCLUSION

This study suggests that a reduced recruitment of naïve T-helper cells and increased frequency of T-helper cells with lymph node homing marker expression reflect mucosal healing in IBD. Surprisingly, the degree of activation of mucosal T-helper cells did not correlate with disease remission.

Interactions between the intestinal microbiota and innate lymphoid cells

The mammalian intestine must manage to contain 100 trillion intestinal bacteria without inducing inappropriate immune responses to these microorganisms. The effects of the immune system on intestinal microorganisms are numerous and well-characterized, and recent research has determined that the microbiota influences the intestinal immune system as well. In this review, we first discuss the intestinal immune system and its role in containing and maintaining tolerance to commensal organisms. We next introduce a category of immune cells, the innate lymphoid cells, and describe their classification and function in intestinal immunology. Finally, we discuss the effects of the intestinal microbiota on innate lymphoid cells.

Clinical utility of newly developed immunoassays for serum concentrations of adalimumab and anti-adalimumab antibodies in patients with Crohn's disease

BACKGROUND/AIM

The appearance of anti-adalimumab antibodies (AAAs) is associated with low serum adalimumab (ADA) trough levels and a decrease of clinical response. The goal of this study was to assess the accuracy and clinical utility of new immunoassays for serum ADA and AAA levels.

PATIENTS AND METHODS

Serum ADA trough levels and AAA levels were measured using new immunoassays in 40 patients with Crohn's disease (CD) receiving ADA maintenance therapy.

RESULTS

Serum ADA trough levels were 12.3 ± 9.6 μg/ml (n = 40) in CD patients, and 14 of 40 patients (35 %) were positive for AAAs. A negative correlation was observed between serum AAA levels and ADA trough levels (y = -6.02x + 18.7, r = -0.54, P < 0.001, n = 40). The ROC (receiver-operator curve) analyses indicated that an ADA trough of 5.9 μg/ml was optimal to maintain negative CRP (C-reactive protein) levels (≤0.3 mg/dl). The ADA trough levels were significantly lower in patients positive for AAAs (5.5 ± 5.4 μg/ml, n = 14) than in patients negative for AAAs (16.0 ± 9.5 μg/ml, n = 26). The CRP and ESR levels were significantly higher in AAA-positive patients than in AAA-negative patients. Serum albumin levels were significantly lower in AAA-positive patients. The positive rate for AAAs in patients who lost a response to infliximab (50 %) was significantly higher than that of anti-TNF-α drug naïve patients (12.5 %).

CONCLUSIONS

These new assays for serum AAA trough and AAA levels are useful for routine clinical use and may help guide selection of optimal management strategies for IBD patients with a loss of response to ADA.

IL-22-producing CD4+ cells are depleted in actively inflamed colitis tissue

T helper type (Th17) cytokines such as interleukin (IL)-17A and IL-22 are important in maintaining mucosal barrier function and may be important in the pathogenesis of inflammatory bowel diseases (IBDs). Here, we analyzed cells from the colon of IBD patients and show that Crohn's disease (CD) patients had significantly elevated numbers of IL-17+, CD4+ cells compared with healthy controls and ulcerative colitis (UC) patients, but these numbers did not vary based on the inflammatory status of the mucosa. By contrast, UC patients had significantly reduced numbers of IL-22+ cells in actively inflamed tissues compared with both normal tissue and healthy controls. There was a selective increase in mono-IL-17-producing cells from the mucosa of UC patients with active inflammation together with increased expression of transforming growth factor (TGF)-β and c-Maf. Increasing concentrations of TGF-β in lamina propria mononuclear cell cultures significantly depleted Th22 cells, whereas anti-TGF-β antibodies increased IL-22 production. When mucosal microbiota was examined, depletion of Th22 cells in actively inflamed tissue was associated with reduced populations of Clostridiales and increased populations of Proteobacteria. These results suggest that increased TGF-β during active inflammation in UC may lead to the loss of Th22 cells in the human intestinal mucosa.

Aquaporin 3 and 8 are down-regulated in TNBS-induced rat colitis

Aquaporins (AQPs) plays an important role in transcellular water movement, but the AQPs expression profile has not been demonstrated in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis which closely mimics human Crohn's disease (CD) histopathologically. To solve the problem, 30 female Sprague-Dawley (SD) rats were randomly divided into a model group (n=18), an ethanol control group (n=6) and a normal control group (n=6). On day 1, the rats in the model group received TNBS+50% ethanol via the rectum, while the ethanol control rats received an equal volume of 50% ethanol and the normal control rats did not receive any treatment. All rats were sacrificed on day 7, and ileum, proximal colon and distal colon specimens were obtained to examine the alteration in AQP3 and AQP8 using real-time polymerase chain reaction, Western blot analysis and immunohistochemistry. As a result, exposure to TNBS+ethanol resulted in a marked decrease in both the mRNA and protein expression of AQP3 and AQP8, with the exception of AQP8 protein which was negative in the distal colon in all three groups. These reductions in AQP3 and AQP8 were accompanied by an increase in intestinal inflammation and injury. The results obtained here implied that both AQP3 and AQP8 may be involved in the pathogenesis of inflammatory bowel disease.

Angiotensin converting enzyme-inhibitor reduces colitis severity in an IL-10 knockout model

BACKGROUND

We previously demonstrated angiotensin converting enzymes (ACE) over-expression in a dextran-sodium sulfate colitis model; ACE inhibitor (ACE-I) treatment reduced colitis severity in this model. However, ACE-I has not been tested in more immunologically relevant colitis models.

AIM

We hypothesized that ACE-I would decrease disease severity in an IL-10 knockout (-/-) colitis model.

METHODS

Colitis was induced by giving 10-week old IL-10-/- mice piroxicam (P.O.) for 14 days. The ACE-I enalaprilat was given transanally at a dose of 6.25 mg/kg for 21 days. Prednisolone (PSL) with or without enalaprilat were used as therapeutic, comparative groups. All groups were compared to a placebo treated group. Outcome measures were clinical course, histology, abundance of pro-inflammatory cytokines/chemokines, and epithelial barrier function.

RESULTS

Enalaprilat exhibited better survival (91 %) versus other treatment groups (PSL: 85.7 %, PSL + ACE-I: 71.4 %, placebo: 66.6 %). The ACE-I and PSL + ACE-I groups showed significantly better histological scores versus placebo mice. ACE-I and the PSL groups significantly reduced several pro-inflammatory cytokines versus placebo mice. FITC-dextran permeability was reduced in the ACE-I and PSL + ACE-I groups. Blood pressure was not affected in ACE-I treated mice compared to placebo mice.

CONCLUSIONS

ACE-I was effective in reducing severity of colitis in an IL-10-/- model. The addition of prednisolone minimally augmented this effect. The findings suggest that appropriately dosed ACE-I with or without steroids may be a new therapeutic agent for colitis.

Vitamin D and Crohn's disease in the adult patient: a review

Crohn's disease (CD) is characterized as a chronic immune-mediated inflammatory disorder of the gastrointestinal tract. Current consensus surrounding the cause of the disease suggests a complex interplay between genetic susceptibility, the intestinal microbiome and environmental factors, leading to the aberrant Th1 and Th17 immune cell mediated response. Vitamin D deficiency is common in CD patients, and long-standing deficiency has been associated with reduced bone mineral density (BMD). Accumulating evidence now suggests that in addition to maintaining skeletal integrity, vitamin D also plays an integral role in regulating the general immune response, a function employed via its genomic actions on the vitamin D receptor (VDR). The VDR is expressed in all immune cells and both directly and indirectly targeted by the bioactive form of vitamin D, 1,25-Dihydroxyvitamin D (1,25[OH]2D). Impaired regulation or deficiency of the vitamin has been linked to the promotion of self-reactive T cell development, loss of immune tolerance to self-structures, and experimental colitis in animal models, whereas the subsequent administration of the vitamin in these models resulted in the improvement of immune-mediated symptoms. In addition, low vitamin D has been associated with disease activity in CD patients, and supplementation appears to be beneficial in improving clinical scores and reducing inflammation. Therefore, the primary aims of this article were to review the molecular evidence supporting the immunoregulatory roles of vitamin D and its supplementation in the CD patient, based on existing literature. The physiological processes, accepted serum concentration values, and its well-recognized role in bone health were also summarized.

Regulation of eotaxin-3/CC chemokine ligand 26 expression by T helper type 2 cytokines in human colonic myofibroblasts

Eotaxins induce the trafficking of eosinophils to the sites of inflammation via CC chemokine receptor 3 (CCR3). In this study, we investigated eotaxin-3/CC chemokine ligand 26 (CCL26) expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD), and characterized the molecular mechanisms responsible for eotaxin-3 expression in human colonic myofibroblasts. Eotaxin-3 mRNA and protein expression was evaluated by real time-polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Eotaxin-3 mRNA expression was elevated significantly in the active lesions of ulcerative colitis (UC) patients. Significant elevations were also observed in the active lesions of Crohn's disease (CD) patients, but this was significantly lower than that detected in the active UC lesions. There were no significant increases in the inactive lesions of UC or CD patients. Colonic myofibroblasts were identified as a major source of eotaxin-3 in the colonic mucosa, and interleukin (IL)-4 and IL-13 enhanced eotaxin-3 mRNA and protein expression significantly in these cells. There was a significant positive correlation between mucosal eotaxin-3 and IL-4 mRNA expression in the active lesions of IBD patients. The IL-4- and IL-13-induced eotaxin-3 mRNA expression was regulated by the signal transducer and activator of transcription-6 (STAT-6) and suppressor of cytokine signalling (SOCS)1-mediated pathways. Interferon (IFN)-γ acts as a negative regulator on the IL-4- and IL-13-induced eotaxin-3 expression via STAT-1 activation. Eotaxin-3 expression was elevated specifically in the active lesions of IBD, in particular UC. Eotaxin-3 derived from colonic myofibroblasts may play an important role in the pathophysiology of UC.

Changes of energy metabolism, nutritional status and serum cytokine levels in patients with Crohn's disease after anti-tumor necrosis factor-α therapy

We investigated the effects of treatment with antibodies against tumor necrosis factor (TNF)-α on energy metabolism, nutritional status, serum cytokine levels in patients with Crohn’s disease (CD). Twelve patients were enrolled. Resting energy expenditure (REE) levels were measured by indirect calorimetry. Crohn’s disease activity index (CDAI) significantly decreased after treatment with anti-TNF-α therapy. Anti-TNF-α therapy did not affect REE, but respiratory quotient (RQ) significantly increased after treatment. Serum interleukin-6 levels were significantly decreased and RQ were significantly increased in high REE (≥25 kcal/kg/day) group as compared to low REE (<25 kcal/kg/day) group. In conclusion, high REE value on admission is a predictive factor for good response to treatment with anti-TNF-α antibodies in active CD patients.

Helicobacter pylori and Crohn’s disease: A retrospective single-center study from China

AIM: To investigate the association between Helicobacter pylori (H. pylori) infection and the prevalence of Crohn’s disease (CD).

METHODS: Subjects were selected from patients admitted the gastrointestinal (GI) department at The First Affiliated Hospital School of Medicine (Zhejiang University) for abdominal pain, hematochezia, diarrhea and other GI symptoms between January 2008 and September 2012. CD was diagnosed by endoscopy and biopsy. H. pylori infection was detected by a ¹⁴C-urea breath test and culturing of the biopsy sample. Demographic, anthropometric and serologic data were collected for each patient. H. pylori infection rate was compared between CD and control groups, followed by a subgroup analysis based on extent and severity of CD. Student’s t, Mann-Whiney U, and χ² tests were used to analyze the data.

RESULTS: A total of 447 patients were analyzed, including 229 in the CD group and 248 in the control group. There were no significant differences in age, sex, and rates of hypertension or diabetes. However, the CD group showed significantly higher rates of smoking history (34.9% vs 18.1%), alcohol intake (17.4% vs 8.1%), white blood cell count (9.7 ± 2.9 × 10⁹/L vs 4.3 ± 0.9 × 10⁹/L), and C-reactive protein (36.3 ± 20.8 mg/L vs 5.5 ± 2.3 mg/L) but lower body mass index (24.5 ± 2.0 kg/m²vs 26.0 ± 2.2 kg/m²) than the control group. The H. pylori infection rate in the CD group was 27.1%, significantly lower than that of 47.9% in the control group. Furthermore, the H. pylori infection rates in patients with colonic, small intestine, ileocolonic and extensive CD were 31.1%, 28.9%, 26.8% and 25.9% respectively, all of which were significantly lower than in the control group. Finally, the H. pylori infection rates in patients with remission, moderate and severe CD were 34.3%, 30.7% and 22.0% respectively, which were also significantly lower than in the control group.

CONCLUSION: Lower H. pylori infection in CD patients suggests a correlation between bacterial infection and CD, suggesting caution when considering H. pylori eradication in CD patients.

Epicutaneous immunization with protein antigen TNP-Ig alleviates TNBS-induced colitis in mice

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory autoimmune disease with limited treatment modalities. The animal model of colitis induced by treatment with trinitrobenzene sulfonic acid (TNBS-colitis) is commonly used to test new therapies of this disease. In our previous work we found that epicutaneous (EC) immunization with protein antigen induced a state of profound immunosuppression that inhibited inflammatory response in contact sensitivity, in experimental autoimmune encephalomyelitis (EAE) and in allogeneic skin graft rejection.

METHODS

TNBS-induced colitis was used as an experimental model.

RESULTS

In our current work, we showed that EC immunization with TNP-conjugated mouse immunoglobulin (TNP-Ig) prior to induction of TNBS-colitis alleviates disease severity what was determined by the body weight, the length and the weight of the colon, the histological activity index (HAI) and myeloperoxidase activity (MPO). Observed amelioration of the disease in TNP-Ig patched mice was accompanied with decreased production of IFN-γ and IL-17A by splenocytes. Additionally, spleen cells isolated from mice EC immunized with TNP-Ig prior to colitis induction showed increased production of IL-10 suggesting that this cytokine might be involved in inhibiting inflammatory response in the colon.

CONCLUSION

This work shows that EC immunization with protein antigen prior to TNBS-colitis induction ameliorates disease and observed suppression of inflammatory response in the colon might be mediated by IL-10.

Epithelial expression of interleukin-37b in inflammatory bowel disease

Interleukin (IL)-37 is a member of the IL-1 cytokine family. We investigated IL-37b expression in the inflamed mucosa of inflammatory bowel disease (IBD) patients. Furthermore, we analysed IL-37b expression in human colonic epithelial cells. The human colonic epithelial cell line T84 and human colonic subepithelial myofibroblasts (SEMFs) were used. IL-37b expression in the IBD mucosa was evaluated by immunohistochemistry. IL-37b mRNA and protein expression were determined by real time-polymerase chain reaction (PCR) and Western blotting, respectively. IL-37b was not detected in the normal colonic mucosa. In the inflamed mucosa of IBD patients, epithelial IL-37b expression was increased markedly. In ulcerative colitis (UC) and Crohn's disease (CD) patients, IL-37b expression was enhanced in the affected mucosa. In the intestinal epithelial cell line T84, the expression of IL-37b mRNA and protein was enhanced by tumour necrosis factor (TNF)-α. This IL-37b induction by TNF-α was mediated by nuclear factor (NF)-κB and activator protein (AP)-1 activation. Furthermore, IL-37b inhibited TNF-α-induced interferon-γ-inducible protein (IP)-10 expression significantly in human colonic SEMFs. Epithelial IL-37b expression was increased in IBD patients, especially UC patients. IL-37b may be involved in the pathophysiology of IBD as an anti-inflammatory cytokine and an inhibitor of both innate and acquired immune responses.

Human polyomavirus JC reactivation and pathogenetic mechanisms of progressive multifocal leukoencephalopathy and cancer in the era of monoclonal antibody therapies

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the neurotropic human polyomavirus JC (JCV) lytic infection of oligodendrocytes. PML was first described as a complication of lymphoproliferative disorders more than 50 years ago and emerged as a major complication of human immunodeficiency virus (HIV) infection in the 1980s. Despite the ubiquity of this virus, PML is rare and always seen in association with underlying immunosuppressive condition, such as HIV infection, autoimmune diseases, cancer, and organ transplantation. JCV remains quiescent in the kidneys, where it displays a stable archetypal non-coding control region (NCCR). Conversely, rearranged JCV NCCR, including tandem repeat patterns found in the brain of PML patients, have been associated with neurovirulence. The specific site and mechanism of JCV NCCR transformation is unknown. According to one model, during the course of immunosuppression, JCV departs from its latent state and after entering the brain, productively infects and destroys oligodendrocytes. Although the majority of PML cases occur in severely immunesuppressed individuals, PML has been increasingly diagnosed in patients treated with biological therapies such as monoclonal antibodies (mAbs) that modulate immune system functions: in fact, CD4+ and CD8+ T lymphopenia, resulting from this immunomodulatory therapy, are the primary risk factor. Furthermore, JCV reactivation in nonpermissive cells after treatment with mAbs, such as intestinal epithelial cells in Crohn's disease patients, in association with other host tumor-inducing factors, could provide valid information on the role of JCV in several malignancies, such as colorectal cancer.

The new prophylactic strategy for colon cancer in inflammatory bowel disease by modulating microbiota

It is well understood that intestinal microbiota play an important role in the pathogenesis of inflammatory bowel disease (IBD). In addition, IBD patients are well known to have a higher risk of developing colon cancer due to chronic inflammation. Recent evidence suggests that manipulation of microbiota improves the clinical outcome of patients with IBD and may reduce onset of colon cancer without obvious toxicity. This review summarizes the current experimental and clinical knowledge about the role of intestinal microbiota in IBD and colon cancer, and the nutraceutical therapy for colon cancer.

Decreased abundance of Faecalibacterium prausnitzii in the gut microbiota of Crohn's disease

BACKGROUND AND AIMS

Dysbiosis is thought to be relevant to the etiology and pathogenesis of Crohn's disease (CD). In this study, we investigated the abundance of Faecalibacterium prausnitzii, as well as Bilophila wadsworthia, in the gut microbiota of Japanese CD patients.

METHODS

Forty-seven CD patients and 20 healthy controls were enrolled. Abundance of F. prausnitzii in fecal samples was quantified by real-time polymerase chain reaction. The gut microbiota profile was evaluated by terminal restriction fragment length polymorphisms.

RESULTS

The abundance of F. prausnitzii significantly decreased in CD patients compared with healthy subjects. B. wadsworthia was scarcely detected in the same samples. Among CD patients, the Crohn's Disease Activity Index, C-reactive protein levels, and erythrocyte sedimentation rate were significantly lower, and serum albumin levels were significantly higher in the high F. prausnitzii group compared with the low group. Terminal restriction fragment length polymorphisms analysis showed that fecal bacterial communities of CD patients differed from those of healthy individuals. The changes in simulated bacterial composition indicated that class Clostridia, including genus Faecalibacterium, was significantly less abundant in CD patients as compared with healthy individuals. The bacterial diversity measured by the Shannon Diversity Index was significantly reduced in CD patients compared with healthy individuals.

CONCLUSION

The decreased abundance of class Clostridia, including F. prausnitzii, may translate into a reduction of commensal bacteria-mediated, anti-inflammatory activities in the mucosa, which are relevant to the pathophysiology of CD. In contrast, the role of B. wadsworthia was suspected to be minimal.

IL-23/IL-17A axis correlates with the nitric oxide pathway in inflammatory bowel disease: immunomodulatory effect of retinoic acid

Inflammatory bowel diseases (IBDs) are chronic inflammatory diseases of the gastrointestinal tract, which are clinically present as 1 of the 2 disorders, Crohn's disease (CD) or ulcerative colitis (UC) (Rogler 2004). The immune dysregulation in the intestine plays a critical role in the pathogenesis of IBD, involving a wide range of molecules, including cytokines. The aim of this work was to study the involvement of T-helper 17 (Th17) subset in the bowel disease pathogenesis by the nitric oxide (NO) pathway in Algerian patients with IBD. We investigated the correlation between the proinflammatory cytokines [(interleukin (IL)-17, IL-23, and IL-6] and NO production in 2 groups of patients. We analyzed the expression of messenger RNAs (mRNAs) encoding Th17 cytokines, cytokine receptors, and NO synthase 2 (NOS2) in plasma of the patients. In the same way, the expression of p-signal transducer and activator of transcription 3 (STAT3) and NOS2 was measured by immunofluorescence and immunohistochemistry. We also studied NO modulation by proinflammatory cytokines (IL-17A, IL-6, tumor necrosis factor α, or IL-1β) in the presence or absence of all-trans retinoic acid (At RA) in peripheral blood mononuclear cells (PBMCs), monocytes, and in colonic mucosa cultures. Analysis of cytokines, cytokine receptors, and NOS2 transcripts revealed that the levels of mRNA transcripts of the indicated genes are elevated in all IBD groups. Our study shows a significant positive correlation between the NO and IL-17A, IL-23, and IL-6 levels in plasma of the patients with IBD. Interestingly, the correlation is significantly higher in patients with active CD. Our study shows that both p-STAT3 and inducible NOS expression was upregulated in PBMCs and colonic mucosa, especially in patients with active CD. At RA downregulates NO production in the presence of proinflammatory cytokines for the 2 groups of patients. Collectively, our study indicates that the IL-23/IL-17A axis plays a pivotal role in IBD pathogenesis through the NO pathway.

Loss of phosphoinositide 3-kinase P110γ is protective in the acute phase but detrimental in the resolution phase of hapten-induced colitis

BACKGROUND

Pharmacologic inhibition or genetic ablation of phosphoinositide 3-kinase gamma (PI3Kγ) has been shown to be protective against experimental colitis. However, the role of PI3Kγ in the resolution phase of colitis remains unexplored. In this study, we assess the effects of genetic knockout of PI3Kγ on the induction and resolution of colitis induced by the hapten trinitrobenzene sulfonic acid (TNBS).

METHODS

Colitis was induced in wild-type C57/Bl6 or PI3Kγ-/- mice by intrarectal administration of 2.5 mg of TNBS in 50% ethanol. Body weights were monitored daily, and colon tissues were collected at days 3, 7, or 14 after treatment, and colitis was assessed using disease activity and histologic damage scores, measurement of tissue myeloperoxidase and neutrophil infiltration, and local cytokine production.

RESULTS

Mice lacking PI3Kγ were significantly protected from disease during the acute phase (day 3) of TNBS colitis. However, PI3Kγ-/- mice have difficulty resolving acute inflammation because they failed to restore lost weight and had significantly elevated histologic damage scores and tissue myeloperoxidase levels at days 7 and 14 after TNBS administration compared with wild-type controls. This phenomenon was dependent on presensitization with TNBS and seems to involve an inability to clear invading bacteria, resulting in the generation of a persistent inflammatory cytokine response.

CONCLUSIONS

This study confirms that PI3Kγ plays a role in the induction of colitis. However, PI3Kγ is also required for the resolution of intestinal damage following acute inflammation. This must be taken into consideration before the inhibition of PI3Kγ can be used as a treatment for disorders such as inflammatory bowel disease.

Interleukin-1 associations in inflammatory bowel disease and the enteropathic seronegative spondylarthritis

Purpose

This study aims to investigate any associations of the proinflammatory cytokine IL-1 in treated patients with inflammatory bowel disease (IBD) and the enteropathic seronegative spondylarthritis (eSpA).

Methods

Thirty-four patients with Crohn’s disease (CD), 26 with ulcerative colitis (UC) and 14 patients with SpA participated in the study. Valid clinical indexes, CRP values and the endoscopic and histologic examination were used for the determination of disease activity. IL-1α, IL-1β, IL-1 receptor antagonist (IL-1Ra) were measured by ELISA. Nonparametric tests were used for continuous and categorical data.

Results

Enteropathic SpA diagnosed in 29.4 % CD and 30.8 % UC patients. Active disease had 58.8 % CD (aCD), 76.9 % UC and 50 % SpA patients. Active and inactive CD (iCD) significantly differ on IL-1α levels (11.2 vs. 3.9 pg/ml; p = 0.034). Active and inactive UC significantly differ on IL-1β (3.7 vs. 2.3 pg/ml; p = 0.054) and IL-1Ra levels (15.9 vs. 12.7 pg/ml; p = 0.023). Active and inactive SpA (iSpA) significantly differ on IL-1Ra (16.9 vs. 14.8 pg/ml; p = 0.033) and marginally on IL-1α levels (20 vs. 3.9 pg/ml; p = 0.06). Patients with aCD/ieSpA exhibited significant differences on IL-1α (p = 0.022) compared to those with iCD/ieSpA.

Conclusions

IL-1α is associated with CD activity, while IL-1β and IL-1Ra are associated with UC activity in treated patients with IBD. Prominent cytokine in SpAs seems to be IL-1α.

Safety and tolerability of human placenta-derived cells (PDA001) in treatment-resistant crohn's disease: a phase 1 study

BACKGROUND

The clinical utility of cellular therapies is being investigated in a broad range of therapeutic areas. This phase 1 study represents the first exploration of PDA001, a preparation of cells cultured from human placental tissue, in subjects with Crohn's disease.

METHODS

Twelve subjects with active, moderate-to-severe Crohn's disease unresponsive to previous therapy were given 2 intravenous infusions of PDA001 1 week apart, monitored weekly for 5 weeks, and assessed at 6 months, 1 year, and 2 years after infusion. Six subjects received 2 infusions of 2 × 10 cells (low dose), and 6 subjects received 2 infusions of 8 × 10 cells (high dose).

RESULTS

Mean baseline Crohn's Disease Activity Index in the low-dose and high-dose groups was 305 and 364, respectively, and mean C-reactive protein was 8 mg/L and 49 mg/L, respectively. All subjects in the low-dose group achieved a clinical response (a Crohn's Disease Activity Index decrease of ≥70 points versus baseline), and 3 achieved remission (a Crohn's Disease Activity Index decrease of ≥100 to <150 points). Two subjects in the high-dose group achieved response, and none met remission criteria. Most adverse events were mild to moderate in severity and included headache, nausea, fever, and infusion site reactions.

CONCLUSIONS

PDA001 infusions appear safe and well-tolerated in subjects with treatment-resistant Crohn's disease. A response was seen in all subjects in the low-dose group. The high-dose group, with a higher baseline disease activity, had only 2 responders, suggesting a more treatment-resistant population. A phase 2 study in this patient population is ongoing.

Sixty-year study of incidence of childhood ulcerative colitis finds eleven-fold increase beginning in 1990s

BACKGROUND

We sought to define the point at which a recently noted marked increase in the incidence of ulcerative colitis (UC) had occurred in children in Victoria, Australia.

METHODS

A 60-year retrospective review (1950-2009) of children age 16 years or less diagnosed with UC in the state's major pediatric centers was performed.

RESULTS

In all, 342 children were diagnosed with UC (male to female ratio of 1.25:1.0, median age 10.9 years, interquartile range [IQR] 7.0, 13.2). The overall median annual incidence of UC was 0.36/10(5) children ≤ 16 years of age (IQR 0.18, 0.66). The number of reported cases increased by 11-fold during the study period (P < 0.001). This marked increase appeared to occur from the early 1990s and has yet to plateau. Children diagnosed during the last two decades were older at diagnosis (median 10 years vs. 11.6, P < 0.0001), and had higher weight- and height-for-age z scores than those diagnosed during the first 40 years (mean weight-for-age [standard deviation] 1950-1989: -0.80 [1.56] vs. 1990-2009: -0.11 [1.17], P < 0.001; mean height-for-age 1950-1989: -0.50 [1.15] vs. 1990-2009: -0.13 [1.12], P < 0.05). More recently diagnosed children also had more extensive disease (1950-1989: 52% vs. 1990-2009: 71%, P < 0.01).

CONCLUSIONS

The incidence of UC has increased markedly in Victorian children since 1990. Although some of this change may be attributable to earlier diagnosis, it is unlikely that this can provide a complete explanation for this still-increasing condition.

A new paradigm in ulcerative colitis: regulatory T cells are key factor which induces/exacerbates UC through an immune imbalance

Leukocytapheresis (LCAP) appears to remove or inactivate inflammatory cells and to reset immunological responses, resulting to cure responders of ulcerative colitis (UC). The changes of T cell subsets were investigated in UC patients treated with LCAP. Levels of T cell subsets in peripheral blood before and after LCAP were analysed by flow cytometric analysis. Of 20 UC patients, 13 (65%) achieved remission and 2 (10%) showed the improvement of UC symptoms. Ratios of some T cell subtypes such as regulatory T (Treg) cells and memory T cells to CD4(+) T cells changed significantly only in responders. Especially, ratio of resting Treg/CD4(+) T cells was significantly increased after the first LCAP session, and then one of activated Treg/CD4(+) T cells was increased after 2 week. This may lead to the development of a new UC paradigm in which an imbalance in Treg cell subsets triggers the onset and/or exacerbation of UC.

Multicenter analysis of fecal microbiota profiles in Japanese patients with Crohn's disease

BACKGROUND

We analyzed the fecal microbiota profiles of patients with Crohn's disease (CD) at 4 inflammatory bowel disease (IBD) centers located in different districts in Japan.

METHODS

Terminal restriction fragment length polymorphism (T-RFLP) analysis was performed in 161 fecal samples from CD patients and 121 samples from healthy individuals. The bacterial diversity was evaluated by the Shannon diversity index (SDI).

RESULTS

There were no regional differences in the fecal microbiota profiles of the healthy individuals in Japan. A setting of similarity generated three major clusters of T-RFs: one included almost all the healthy individuals (118/121), and the other two clusters were mainly formed by CD patients at different stages of disease activity. The changes in simulated bacterial composition indicated that the class Clostridia, including the genus Faecalibacterium, was significantly decreased in CD patients with active disease and those in remission as compared with findings in the healthy individuals. In contrast, the genus Bacteroides was significantly increased in CD patients during the active phase as compared with findings in the healthy individuals. The genus Bifidobacterium was significantly decreased during the active phase of CD and increased to healthy levels during the remission phase. The bacterial diversity measured by the SDI was significantly reduced in CD patients during the active and remission phases as compared with findings in the healthy individuals. From the clinical data and T-RFLP analysis, we developed a logistic model to predict disease activity based on the fecal microbiota composition.

CONCLUSION

Dysbiosis in CD patients was shown by a multi-IBD center study. The feasibility of using the fecal microbiota profile as a predictive marker for disease activity is proposed.

NKG2D/Ligand dysregulation and functional alteration of innate immunity cell populations in pediatric IBD

BACKGROUND

Dysregulated innate immune responses play an important role in inflammatory bowel disease (IBD). NKG2D innate immunity receptor is a major sensor of tissue damage that, by recognizing multiple stress-induced, cell-associated ligands (MIC-A/B and ULBP1-5), potentiates the effector functions of "innate-like" (γ/δ TcR+, and natural killer receptor+ [NKR+]) T-cell populations. We analyzed the representivity, NKG2D/ligand expression pattern, and functional ability of the major innate immunity cell populations in pediatric IBD patients.

METHODS

We analyzed 41 Crohn's disease (CD) patients, 33 ulcerative colitis (UC) patients, and 51 age-matched non-IBD controls. The expression of NKG2D and its ligands, interferon-gamma (IFN-γ) production, and cytotoxic granule release were assessed by immunostaining and multiparameter cytofluorimetric analysis on circulating and mucosal mononuclear subsets; the inflammatory infiltrate was also characterized by immunohistochemistry.

RESULTS

The expression pattern of NKG2D receptor and its ligands on mucosal and circulating innate immunity populations is severely disturbed in IBD; NKG2D and ligands are upregulated on immune infiltrate in both CD and UC active lesions; receptor/ligand upregulation also occurs on circulating leukocyte populations, where it depends on both disease activity and type (UC vs. CD). Finally, the frequency and effector capability of peripheral blood "innate-like" T-cell populations are also altered in IBD patients.

CONCLUSIONS

The circulating and mucosal innate immunity compartment is phenotypically and functionally altered in pediatric IBD; some alterations may represent a distinctive feature of the pediatric disease condition. The disturbance of NKG2D/ligand pathway may play a role in sustaining immune activation which leads to chronic inflammatory tissue damage.

Expression of PPAR γ in intestinal epithelial cells is dispensable for the prevention of colitis by dietary abscisic acid

BACKGROUND & AIMS

Dietary abscisic acid (ABA) has shown efficacy in ameliorating experimental IBD in mice through mechanisms requiring expression of peroxisome proliferator activated-receptor γ (PPAR γ) in immune cells. The goal of this study was to determine whether PPAR γ expression in colonic epithelial cells is required for the anti-inflammatory actions of ABA.

METHODS

Conditional knockout mice expressing a transgenic recombinase in intestinal epithelial cells under the control of a villin promoter (PPAR γ flfl; Villin Cre+ or VC+) with defective expression of PPAR γ in intestinal cells (IEC) and PPAR γ-expressing wild type (PPAR γ flfl; Villin Cre- or VC-) mice in a C57BL/6 background were fed diets with and without ABA (0.1 g/kg) for 35 days and challenged with 2.5% dextran sodium sulfate (DSS) in the drinking water for 7 days. Clinical disease severity was assessed daily and colonic lesions on day 7 through macroscopic and histopathological examination. Immune cell phenotypes were examined systemically and at the mesenteric lymph nodes (MLN). Epithelial gene expression was assayed in the colon.

RESULTS

Dietary ABA-supplementation prevented colitis, reduced disease severity, improved colonic histopathology, and upregulated epithelial lanthionine synthetase C-like protein 2 (LANCL2) expression in VC+ mice. Dietary ABA significantly increased the percentages of MLN CD4+IL-10+ T cells, and blood CD4+CD25+FoxP3+ T cells and CD8+IL-10+ T cells.

CONCLUSION

Expression of PPAR γ in IECs was not required for the anti-inflammatory efficacy of ABA in IBD. LANCL2 in IECs and T cell-derived IL-10 may be implicated in the mechanism underlying ABA's immune modulatory activity in IBD.

Effects of Rhizophora mangle on Experimental Colitis Induced by TNBS in Rats

Male Unib-WH rats were pretreated for two weeks with butanolic (BuOH) and ethyl acetate (EtOAc) fractions. Colitis was induced by rectal administration of TNBS, the treatment continued, and animals were sacrificed on day 7 after the TNBS administration. Phytochemical studies were performed in order to provide the characterization of the tannins present in the bark of R. mangle. Results showed that EtOAc fraction increased the levels of IL-10 (∗∗P < 0.01) and diminished the levels of TNF-α (∗∗∗P < 0.001) and IL-6 (∗∗P < 0.01). BuOH fraction reduced the MPO activity (∗∗P < 0.01) and levels of TBARS (∗∗∗P < 0.001); it also increased COX-1 expression, diminished the levels of TNF-α (∗∗∗P < 0.001), and increased the levels of IL-12 (∗∗∗P < 0.001). Besides, both treatments augmented the levels of GSH (∗P < 0.05), the activity of GSH-Px (∗∗P < 0.01 for BuOH fraction and ∗∗∗P < 0.001 for EtOAc fraction), and CAT (∗∗P < 0.01). In conclusion, both treatments ameliorated the injury induced by TNBS through different mechanisms, probably by their chemical composition which directed its activity into an antioxidant or anti-inflammatory response, leading to an immune modulation.

Tacrolimus (FK506) suppresses TNF-α-induced CCL2 (MCP-1) and CXCL10 (IP-10) expression via the inhibition of p38 MAP kinase activation in human colonic myofibroblasts

In order to investigate the molecular mechanisms underlying the immunosuppressive effects of tacrolimus (FK506) on intestinal inflammation, we examined whether FK506 effects cytokine/chemokine secretion in human colonic myofibroblasts. Human colonic myofibroblasts were isolated from normal human colonic tissue. The mRNA and protein expression for human CCL2 and CXCL10 were analyzed by real-time PCR and ELISA, respectively. p38 MAP kinase activation was evaluated by western blotting. Tacrolimus (1 µM) suppressed tumor necrosis factor (TNF)-α-induced CCL2 and CXCL10 mRNA expression, but did not modulate TNF-α-induced interleukin (IL)-6 or CXCL8 mRNA expression. Dose-dependent, inhibitory effects of tacrolimus on CCL2 and CXCL10 expression were observed at the mRNA and protein levels. Significant inhibitory effects of tacrolimus were observed at concentrations as low as 0.5 µM for CCL2 and 0.1 µM for CXCL10, respectively. TNF-α-induced CCL2 and CXCL10 expression depended on p38 MAP kinase activation, and tacrolimus strongly inhibited the TNF-α-induced phosphorylation of p38 MAP kinase. Tacrolimus did not affect interferon (IFN)-γ-induced signaling transducer and activator of transcription (STAT)-1 phosphorylation, nor did it modulate CXCL10 mRNA and protein expression. In conclusion, tacrolimus suppressed CCL2 and CXCL10 expression in human colonic myofibroblasts. These inhibitory effects of tacrolimus may play key roles in the therapeutic effects of colonic inflammation in inflammatory bowel disease (IBD) patients.

MC-12, an annexin A1-based peptide, is effective in the treatment of experimental colitis

Annexin A1 (ANXA1) inhibits NF-κB, a key regulator of inflammation, the common pathophysiological mechanism of inflammatory bowel diseases (IBD). MC-12, an ANXA1-based tripeptide, suppresses NF-κB activation. Here, we determined the efficacy of MC-12 in the control of IBD. Mice with colitis induced by dextran sodium sulfate (DSS) or 2,4,6-trinitro benzene sulfonic acid (TNBS) were treated with various doses of MC-12 administered intraperitoneally, orally or intrarectally. We determined colon length and the histological score of colitis, and assayed: in colon tissue the levels of TNF-α, IFN-γ, IL-1β, IL-6 and IL-10 by RT-PCR; prostaglandin E₂ (PGE₂), cytoplasmic phospholipase A₂ (cPLA₂) and myeloperoxidase by immunoassay; and COX-2 and NF- κB by immunohistochemistry; and in serum the levels of various cytokines by immunoassay. In both models MC-12: reversed dose-dependently colonic inflammation; inhibited by up to 47% myeloperoxidase activity; had a minimal effect on cytoplasmic phospholipase A₂; reduced significantly the induced levels of TNF-α, IFN-γ, IL-1β, IL-6 and IL-10, returning them to baseline. DSS and TNBS markedly activated NF-κB in colonic epithelial cells and MC-12 decreased this effect by 85.8% and 72.5%, respectively. MC-12 had a similar effect in cultured NCM460 normal colon epithelial cells. Finally, MC-12 suppressed the induction of COX-2 expression, the level of PGE₂ in the colon and PGE₂ metabolite in serum. In conclusion, MC-12, representing a novel class of short peptide inhibitors of NF-κB, has a strong effect against colitis in two preclinical models recapitulating features of human IBD. Its mechanism of action is complex and includes pronounced inhibition of NF-κB. MC-12 merits further development as an agent for the control of IBD.

Mitochondria at the interface between danger signaling and metabolism: role of unfolded protein responses in chronic inflammation

Inflammatory bowel diseases (IBDs), like many other chronic diseases, feature multiple cellular stress responses including endoplasmic reticulum (ER) unfolded protein response (UPR). Maintaining protein homeostasis is indispensable for cell survival and, consequently, distinct signaling pathways have evolved to transmit organelle stress. While the ER UPR, aiming to restore ER homeostasis after challenges to ER function, has been extensively studied in the context of chronic diseases, only recently the related mitochondrial UPR (mtUPR), induced by disturbances of mitochondrial proteostasis, has drawn some attention. ER and mitochondria are in close contact and interact physically and functionally. Accumulating data have placed mitochondria at the center of diverse cellular functions and suggest mitochondria as integrators of signaling pathways such as autophagy and inflammation. Consequently, it is likely that mitochondrial stress and ER stress cannot be regarded separately and that mitochondrial stress, as well as ER stress, participates in the pathology of IBD. Protein homeostasis is particularly sensitive toward infections, oxidative stress, and energy deficiency. Thus, environmental disturbances impacting organelle function lead to the concerted activation of distinct UPRs. The metabolic status might therefore serve as an innate mechanism to sense the epithelial environment, including luminal-derived and host-derived factors. This review highlights mtUPR and its interrelation with ER UPR, focuses on recent studies identifying mitochondria as integrators of cellular danger signaling, and, furthermore, illustrates the importance ER UPR and mitochondrial dysfunction in IBD.

Serpin B1 protects colonic epithelial cell via blockage of neutrophil elastase activity and its expression is enhanced in patients with ulcerative colitis

Serpin B1 is a monocyte neutrophil elastase (NE) inhibitor and is one of the most efficient inhibitors of NE. In the present study, we investigated the role of serpin B1 in the pathogenesis of ulcerative colitis by using clinical samples and an experimental model. The colonic expression of serpin B1 was determined by real-time polymerase chain reaction (PCR), Western blot analysis, and immunohistological studies in both normal and inflamed mucosa from patients with ulcerative colitis. Serpin B1 mRNA expression was determined by real-time PCR in the mouse dextran sodium sulfate (DSS)-induced colitis model. Young adult mouse colonic epithelial (YAMC) cells were used to determine the role of serpin B1. Serpin B1 gene transfected YAMC cells were treated with H(2)O(2) to measure cell viability. The expression of NE was determined in YAMC cells treated with H(2)O(2). NE-silenced YAMC cells were also treated with H(2)O(2) and then measured for viability. Upregulated expression of serpin B1 in colonic mucosa was confirmed from patients with active ulcerative colitis. Immunohistochemical studies showed that serpin B1 expression was localized not only in inflammatory infiltration cells but also in epithelial cells. Serpin B1 mRNA expression was also increased in colonic mucosa of mouse DSS-induced colitis. Serpin B1-transfected YAMC cells were resistant against the treatment of H(2)O(2). H(2)O(2) treatment significantly induced NE in YAMC cells, and NE-silenced YAMC cells were also resistant against the treatment of H(2)O(2). These results suggest that serpin B1 may be a novel marker of active ulcerative colitis and may play an important role in the pathogenesis of inflammatory bowel disease.

Mucosal cytokine gene expression profiles as biomarkers of response to infliximab in ulcerative colitis

OBJECTIVE

Mucosal cytokine profile determines T cell differentiation and may play an important role in the clinical course of inflammatory bowel disease (IBD). Cytokines from different T helper (Th) cell subsets are elevated in inflamed mucosa of patients with ulcerative colitis (UC), contributing to the inflammation. The aim of this study was to determine the predictive value of pre-treatment mucosal cytokine profile in response to therapy with the anti-TNF agent infliximab (IFX).

MATERIAL AND METHODS

The expression of Th1, Th17, Th2 and T-regulatory (Treg)-related cytokines was quantified by real-time PCR in mucosal biopsies from 74 UC patients before initiation of IFX induction therapy. Clinical and endoscopic effects were assessed after three infusions. Remission was defined as ulcerative colitis disease activity index (UCDAI) below 3.

RESULTS

Higher gene expression levels of IL-17A and IFN-γ were significantly associated with remission after three IFX infusions (OR = 5.4, p = 0.013 and OR = 5.5, p = 0.011, respectively). IL-17A and IFN-γ mRNA expression showed positive correlation. Th2 and Treg-related mediators were not significantly associated with clinical outcome, but were expressed at higher levels in UC patients compared with the controls. Immunohistochemistry (IHC) confirmed the presence of cells expressing both IL-17A and IFN-γ.

CONCLUSIONS

High expression of Th1- and Th17-related cytokines in the mucosa of UC patients can potentially predict a favorable outcome of IFX induction therapy. Th2 and Treg-related mediators do not appear useful as predictive markers.

Crohn's disease and the mycobacterioses: a quarter century later. Causation or simple association?

It has been more than 25 years since Mycobacterium paratuberculosis was first proposed as an etiologic agent in Crohn's disease based on the isolation of this organism from several patients. Since that time, a great deal of information has been accumulated that clearly establishes an association between M. paratuberculosis and Crohn's disease. However, data are conflicting and difficult to interpret and the field has become divided into committed advocates and confirmed skeptics. This review is an attempt to provide a thorough and objective summary of current knowledge from both basic and clinical research from the views and interpretations of both the antagonists and proponents. The reader is left to draw his or her own conclusions related to the validity of the issues and claims made by the opposing views and data interpretations. Whether M. paratuberculosis is a causative agent in some cases or simply represents an incidental association remains a controversial topic, but current evidence suggests that the notion should not be so readily dismissed. Remaining questions that need to be addressed in defining the role of M. paratuberculosis in Crohn's disease and future implications are discussed.

Human neutrophil peptide-1 aggravates dextran sulfate sodium-induced colitis

BACKGROUND

Human neutrophil peptide (HNP)-1, HNP-2, and HNP-3 (HNP-1-3) are useful biomarkers for ulcerative colitis (UC). The precise roles of these peptides in UC are poorly understood, however. The aim of this study was to determine whether HNP-1 affects disease activity in mice with experimental colitis.

METHODS

Experimental colitis was induced in BALB/c or severe combined immunodeficiency (SCID) mice using dextran sulfate sodium (DSS). Mice were subsequently treated intraperitoneally with HNP-1 (100 μg/day) or phosphate-buffered saline (PBS) from day 4 to day 6. The severity of colitis was evaluated based on a disease activity index, histologic score, and cytokine expression.

RESULTS

Body weight and colon length significantly decreased and the disease activity index score, histologic score, and myeloperoxidase activity significantly increased in HNP-1-treated BALB/c mice compared with PBS-treated mice. Interferon-γ and tumor necrosis factor-α levels in colon culture supernatants-derived HNP-1-treated mice were also significantly higher, and interleukin (IL)-1β levels tended to increase in response to HNP-1. In addition, treating SCID mice with HNP-1 aggravated DSS-induced colitis and IL-1β levels in colon culture supernatants from these mice were significantly higher than in cultures obtained from control mice. Furthermore, in both BALB/c and SCID mice increased recruitment of F4/80-positive macrophages was observed in the inflamed colonic mucosa following HNP-1 injections.

CONCLUSIONS

High concentrations of HNP-1 aggravate DSS-induced colitis, including upregulated expression of such macrophage-derived cytokines as IL-1β. These results indicate that high concentrations of HNP-1-3 in patients with UC may exacerbate disease activity via increased cytokine production.

Host-microbe relationships in inflammatory bowel disease detected by bacterial and metaproteomic analysis of the mucosal-luminal interface

BACKGROUND

Host-microbe interactions at the intestinal mucosal-luminal interface (MLI) are critical factors in the biology of inflammatory bowel disease (IBD).

METHODS

To address this issue, we performed a series of investigations integrating analysis of the bacteria and metaproteome at the MLI of Crohn's disease, ulcerative colitis, and healthy human subjects. After quantifying these variables in mucosal specimens from a first sample set, we searched for bacteria exhibiting strong correlations with host proteins. This assessment identified a small subset of bacterial phylotypes possessing this host interaction property. Using a second and independent sample set, we tested the association of disease state with levels of these 14 "host interaction" bacterial phylotypes.

RESULTS

A high frequency of these bacteria (35%) significantly differentiated human subjects by disease type. Analysis of the MLI metaproteomes also yielded disease classification with exceptional confidence levels. Examination of the relationships between the bacteria and proteins, using regularized canonical correlation analysis (RCCA), sorted most subjects by disease type, supporting the concept that host-microbe interactions are involved in the biology underlying IBD. Moreover, this correlation analysis identified bacteria and proteins that were undetected by standard means-based methods such as analysis of variance, and identified associations of specific bacterial phylotypes with particular protein features of the innate immune response, some of which have been documented in model systems.

CONCLUSIONS

These findings suggest that computational mining of mucosa-associated bacteria for host interaction provides an unsupervised strategy to uncover networks of bacterial taxa and host processes relevant to normal and disease states. (Inflamm Bowel Dis 2012;).

Carbohydrate Elimination or Adaptation Diet for Symptoms of Intestinal Discomfort in IBD: Rationales for "Gibsons' Conundrum"

Therapeutic use of carbohydrates in inflammatory bowel diseases (IBDs) is discussed from two theoretical, apparent diametrically opposite perspectives: regular ingestion of prebiotics or withdrawal of virtually all carbohydrate components. Pathogenesis of IBD is discussed connecting microbial flora, host immunity, and genetic interactions. The best studied genetic example, NOD2 in Crohn's disease, is highlighted as a model which encompasses these interactions and has been shown to depend on butyrate for normal function. The role of these opposing concepts in management of irritable bowel syndrome (IBS) is contrasted with what is known in IBD. The conclusion reached is that, while both approaches may alleviate symptoms in both IBS and IBD, there is insufficient data yet to determine whether both approaches lead to equivalent bacterial effects in mollifying the immune system. This is particularly relevant in IBD. As such, caution is urged to use long-term carbohydrate withdrawal in IBD in remission to control IBS-like symptoms.

Campylobacter jejuni disrupts protective Toll-like receptor 9 signaling in colonic epithelial cells and increases the severity of dextran sulfate sodium-induced colitis in mice

Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation associated with a dysregulated immune response to commensal bacteria in susceptible individuals. The relapse of IBD may occur following an infection with Campylobacter jejuni. Apical epithelial Toll-like receptor 9 (TLR9) activation by bacterial DNA is reported to maintain colonic homeostasis. We investigated whether a prior C. jejuni infection disrupts epithelial TLR9 signaling and increases the severity of disease in a model of mild dextran sulfate sodium (DSS) colitis in mice. In a further attempt to identify mechanisms, T84 monolayers were treated with C. jejuni followed by a TLR9 agonist. Transepithelial resistance (TER) and dextran flux across confluent monolayers were monitored. Immunohistochemistry, Western blotting, and flow cytometry were used to examine TLR9 expression. Mice colonized by C. jejuni lacked any detectable pathology; however, in response to low levels of DSS, mice previously exposed to C. jejuni exhibited significantly reduced weight gain and increased occult blood and histological damage scores. Infected mice treated with DSS also demonstrated a significant reduction in levels of the anti-inflammatory cytokine interleukin-25. In vitro studies indicated that apical application of a TLR9 agonist enhances intestinal epithelial barrier function and that this response is lost in C. jejuni-infected monolayers. Furthermore, infected cells secreted significantly more CXCL8 following the basolateral application of a TLR9 agonist. Surface TLR9 expression was reduced in C. jejuni-infected monolayers subsequently exposed to a TLR9 agonist. In conclusion, infection by C. jejuni disrupts TLR9-induced reinforcement of the intestinal epithelial barrier, and colonization by C. jejuni increases the severity of mild DSS colitis.

Campylobacter jejuni disrupts protective Toll-like receptor 9 signaling in colonic epithelial cells and increases the severity of dextran sulfate sodium-induced colitis in mice

Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation associated with a dysregulated immune response to commensal bacteria in susceptible individuals. The relapse of IBD may occur following an infection with Campylobacter jejuni. Apical epithelial Toll-like receptor 9 (TLR9) activation by bacterial DNA is reported to maintain colonic homeostasis. We investigated whether a prior C. jejuni infection disrupts epithelial TLR9 signaling and increases the severity of disease in a model of mild dextran sulfate sodium (DSS) colitis in mice. In a further attempt to identify mechanisms, T84 monolayers were treated with C. jejuni followed by a TLR9 agonist. Transepithelial resistance (TER) and dextran flux across confluent monolayers were monitored. Immunohistochemistry, Western blotting, and flow cytometry were used to examine TLR9 expression. Mice colonized by C. jejuni lacked any detectable pathology; however, in response to low levels of DSS, mice previously exposed to C. jejuni exhibited significantly reduced weight gain and increased occult blood and histological damage scores. Infected mice treated with DSS also demonstrated a significant reduction in levels of the anti-inflammatory cytokine interleukin-25. In vitro studies indicated that apical application of a TLR9 agonist enhances intestinal epithelial barrier function and that this response is lost in C. jejuni-infected monolayers. Furthermore, infected cells secreted significantly more CXCL8 following the basolateral application of a TLR9 agonist. Surface TLR9 expression was reduced in C. jejuni-infected monolayers subsequently exposed to a TLR9 agonist. In conclusion, infection by C. jejuni disrupts TLR9-induced reinforcement of the intestinal epithelial barrier, and colonization by C. jejuni increases the severity of mild DSS colitis.

Development of a new immunoassay for the accurate determination of anti-infliximab antibodies in inflammatory bowel disease

BACKGROUND

The formation of antibodies to infliximab (ATIs) is closely associated with the loss of response to infliximab in patients with inflammatory bowel disease (IBD). We evaluated the clinical utility of a novel method to measure serum ATI levels in the presence of infliximab.

METHODS

ATI levels were measured using a novel immunoassay and the conventional method in 58 patients with Crohn's disease (CD) under infliximab maintenance therapy. The serum infliximab trough levels were determined by enzyme-linked immunosorbent assay.

RESULTS

ATIs were detected in 16 out of 58 patients (27.6%) by the new method, but the conventional method detected only 2 patients (3.4%) who had the two highest ATI titers assayed by the new method. The presence of ATIs in the samples positive by the new method but negative by the conventional method was confirmed by Western blot analysis. Western blotting analysis also indicated that the new method could restore the binding capacities of the ATIs whose recognition sites were occupied by free infliximab. In the new method, the addition of infliximab to the samples dose-dependently blocked the detection of ATIs. Patients positive for ATIs had significantly lower serum trough levels of infliximab (P < 0.01) and significantly higher clinical activity scores (P < 0.001) as compared with patients negative for ATI.

CONCLUSIONS

The new method makes it possible to measure serum ATI levels in the presence of infliximab. This method is useful for deciding the optimal management strategies for IBD patients with loss of response to infliximab.

Inflammatory bowel disease

Crohn disease and ulcerative colitis are the most common forms of inflammatory bowel disease (IBD) likely to be encountered in primary care. Patient-centered care is essential for positive outcomes, and should include long-term continuity with an empathetic primary care provider who can provide skillful coordination of the requisite multidisciplinary approach. Early suspicion of the diagnosis and referral to expert gastroenterologists for confirmation and medical management is essential. Coordinating interdisciplinary consultations, including colorectal surgeons, radiologists, stoma therapists, psychologists, and rheumatologists, in combination with comprehensive patient education, is key to decreasing overall morbidity, mortality, and health care costs associated with IBD.

Faecal chitinase 3-like-1: a novel biomarker of disease activity in paediatric inflammatory bowel disease

BACKGROUND

Chitinase 3-like-1 (CHI3L1) is up-regulated in the inflamed mucosa of inflammatory bowel disease (IBD).

AIM

To evaluate the usefulness of a faecal CHI3L1 assay, as a reliable marker for predicting the severity of paediatric IBD.

METHODS

Faecal samples were obtained from ulcerative colitis (UC, n = 94), Crohn's disease (CD, n = 87), and healthy individuals (n = 56). The faecal CHI3L1 and calprotectin levels were determined by ELISA. For endoscopic evaluation, the sum of the Matts' score for UC and the simple endoscopic score for CD (SES-CD) were used. Ileal lesions were evaluated by ultrasonography.

RESULTS

Faecal CHI3L1 levels were significantly elevated in active UC (median 366.6 ng/g, n = 44) and active CD (median 632.7 ng/g, n = 48) patients, as compared with healthy individuals (median 2.2 ng/g, n = 56). In UC patients, the faecal CHI3L1 levels were positively correlated with the sum of the Matts' score (r = 0.73, P < 0.01, n = 42). In CD patients, there was a significant correlation between faecal CHI3L1 levels and endoscopic activity as determined by the SES-CD scoring system (r = 0.61, P < 0.01, n = 25). The faecal CHI3L1 levels of patients with wall thickening of their small intestine were significantly higher than those of healthy controls or patients without wall thickening. The cutoff value of 13.7 ng/g for fecal CHI3L1(the 95th percentile of the control value) predicted active lesions in IBD patients with a sensitivity of 84.7% and a specificity of 88.9%.

CONCLUSION

Faecal CHI3L1 assays may be useful for predicting the severity and activity of mucosal inflammation in IBD.

TH1 and TH17 interactions in untreated inflamed mucosa of inflammatory bowel disease, and their potential to mediate the inflammation

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) have been associated with a T helper1 (TH1) and a TH2 cytokine profile, respectively. Recently, a TH17 lineage has been introduced, but their role in the inflammation of CD and UC is not fully understood.

AIM

To characterize the cytokines directing the TH17 cells and their interactions with TH1 cells in the mucosa of untreated patients with CD and UC.

METHOD

Seventy-nine patients with untreated UC, 32 patients with untreated CD and 23 controls with no signs of colon disease were included in the study. Clinical indices for ulcerative colitis (UCDAI) and Crohn's disease (CDAI) were assessed. Biopsies for measurements of interleukin (IL)-17A, IL-23, IL-6, transforming growth factor-beta (TGF-β), interferon-gamma (IFN-γ), mRNA levels as well as immunohistochemical (IHC) analyses were performed.

RESULTS

The gene expression for all cytokines in UC and for all cytokines except for TGF-β in CD were significantly increased compared with the controls. The immunohistochemical analysis showed significantly increased number of IL-17A positive cells in lamina propria and epithelium of both UC and CD compared to controls. The levels of IL-17A and IL-23 mRNA were significantly higher in UC than in CD while the levels of IL-6 were significantly higher in CD compared with UC. The levels of IL-17A, IL-6 and IL-23 mRNA were associated with the disease activity score in both UC and CD. IFN-γ was associated with the disease activity in UC, but did not reach significant level in CD.

CONCLUSION

Increased levels of IL-17A and IL-23 were found in both UC and CD compared to controls. Association to the grade of inflammation and clinical activity was also observed. IL-17A and IL-23 were significantly higher in UC than in CD. TH1 and TH17 cytokines seem to act synergistically in inflammatory bowel disease (IBD) with no apparent polarization between UC and CD.