Mucosal cytokine network in inflammatory bowel disease

Phototherapy with artificial light suppresses dextran sulfate sodium-induced colitis in a mouse model

BACKGROUND AND AIM

Medical treatment for inflammatory bowel disease (IBD) requires chronic administration and causes side effects. Recently, anti-inflammatory effects of phototherapy were reported in animal models. The present study evaluated whether phototherapy improves dextran sulfate sodium (DSS)-induced colitis in a mouse model of IBD.

METHODS

Mice were divided into four equal groups: Control, DSS, DSS + light low (LL), and DSS + light high (LH) groups. Normal fluorescent light intensity in the Control and DSS groups was 200 lux. Artificial light intensities were as follows: DSS + LL group, 1000 lux; DSS + LH group, 2500 lux. After administering phototherapy for 7 days, we evaluated disease activity index (DAI), histological score, colon length/weight, serum 1,25-dihydroxyvitamin D(3) level, and serum and colonic cytokines in the mice.

RESULTS

DAI and histological scores were significantly lower in the DSS + LL group than in the DSS group (both, P < 0.05). Colon length and weight were significantly higher in the DSS + LL group than in the DSS group (both, P < 0.05). Serum interleukin (IL)-6, TNF-α, and IL-17 in the DSS + LL group were significantly lower, and serum and colonic IL-10 were significantly higher in the DSS + LL group than in the DSS group (all, P < 0.05). Serum 1,25-dihydroxyvitamin D(3) levels in the DSS + LH group were significantly increased compared with those in the DSS + LL and DSS groups.

CONCLUSION

Artificial light phototherapy suppressed DSS-induced colitis in mice by suppression of pro-inflammatory cytokines and promotion of anti-inflammatory cytokines.

Synergistic effect of interleukin-10-receptor variants in a case of early-onset ulcerative colitis

AIM: To investigated the molecular cause of very early-onset ulcerative colitis (UC) in an 18-mo-old affected child.

METHODS: We analysed the interleukin-10 (IL10) receptor genes at the DNA and RNA level in the proband and his relatives. Beta catenin and tumor necrosis factor-α (TNFα) receptors were analysed in the proteins extracted from peripheral blood cells of the proband, his relatives and familial adenomatous polyposis (FAP) and PTEN hamartoma tumor syndrome (PHTS) patients. Samples were also collected from the proband’s inflamed colorectal mucosa and compared to healthy and tumour mucosa collected from a FAP patient and patients affected by sporadic colorectal cancer (CRC). Finally, we examined mesalazine and azathioprine effects on primary fibroblasts stabilised from UC and FAP patients.

RESULTS: Our patient was a compound heterozygote for the IL10RB E47K polymorphism, inherited from his father, and for a novel point mutation within the IL10RA promoter (the -413G->T), inherited from his mother. Beta catenin and tumour necrosis factor α receptors-I (TNFRI) protein were both over-expressed in peripheral blood cells of the proband’s relatives more than the proband. However, TNFRII was over-expressed only in the proband. Finally, both TNFα-receptors were shown to be under-expressed in the inflamed colon mucosa and colorectal cancer tissue compared to healthy colon mucosa. Consistent with this observation, mesalazine and azathioprine induced, in primary fibroblasts, IL10RB and TNFRII over-expression and TNFRI and TNFα under-expression. We suggest that β-catenin and TNFRI protein expression in peripheral blood cells could represent molecular markers of sub-clinical disease in apparently healthy relatives of patients with early-onset UC.

CONCLUSION: A synergistic effect of several variant alleles of the IL10 receptor genes, inherited in a Mendelian manner, is involved in UC onset in this young child.

Inducible interleukin 32 (IL-32) exerts extensive antiviral function via selective stimulation of interferon λ1 (IFN-λ1)

Interleukin (IL)-32 has been recognized as a proinflammatory cytokine that participates in responses to viral infection. However, little is known about how IL-32 is induced in response to viral infection and the mechanisms of IL-32-mediated antiviral activities. We discovered that IL-32 is elevated by hepatitis B virus (HBV) infection both in vitro and in vivo and that HBV induced IL-32 expression at the level of both transcription and post-transcription. Furthermore, microRNA-29b was found to be a key factor in HBV-regulated IL-32 expression by directly targeting the mRNA 3'-untranslated region of IL-32. Antiviral analysis showed that IL-32 was not sufficient to alter HBV replication in HepG2.2.15 cells. To mimic the viremic phase of viral infection, freshly isolated peripheral blood mononuclear cells were treated with IL-32γ, the secretory isoform, and the supernatants were used for antiviral assays. Surprisingly, these supernatants exhibited extensive antiviral activity against multiplex viruses besides HBV. Thus, we speculated that the IL-32γ-treated peripheral blood mononuclear cells produced and secreted an unknown antiviral factor. Using antibody neutralization assays, we identified the factor as interferon (IFN)-λ1 and not IFN-α. Further studies indicated that IL-32γ effectively inhibited HBV replication in a hydrodynamic injection mouse model. Clinical data showed that elevated levels of IFN-λ1 both in serum and liver tissue of HBV patients were positively correlated to the increased levels of IL-32. Our results demonstrate that elevated IL-32 levels during viral infection mediate antiviral effects by stimulating the expression of IFN-λ1.

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.

Influence of triterpenoids present in apple peel on inflammatory gene expression associated with inflammatory bowel disease (IBD)

Various ursanic, oleanic and lupanic pentacyclic triterpenoids found in apple peel were studied for anti-inflammatory effects in vitro using T84 colon carcinoma cells. After pretreatment with single triterpenoids, cells were stimulated with pro-inflammatory cytokines (TNF-α, INF-γ, IL-1β). Regulation of mRNA expression was analysed for three specific inflammation-associated marker genes (TNF-α, IL-8, IP-10) using qRT-PCR. Furthermore, the effects of ursolic acid (UA) and oleanolic acid (OA) on the synthesis of certain pro-inflammatory proteins were examined. IP-10 expression was inhibited in a dose-dependent manner by all the tested compounds at concentrations ≥25 μM. The mRNA expression of TNF-α was slightly affected and the IL-8 level was increased. At the protein level, UA and OA (25 μM) reduced the synthesis of IP-10; sICAM-1, IL-23 and GROα were slightly repressed. The TNF-α level was not modulated, whereas induction of IL-8 was increased. UA also enhanced the synthesis of IL-1ra, while OA suppressed the level of I-TAC. The present study confirms that triterpenoids present in apple peel and β-damascone may be implicated in the anti-inflammatory properties of apple constituents, suggesting that these substances might be helpful in the treatment of IBD as nutrient supplements.

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.

Angioedema associated with Crohn's disease: Response to biologics

A 46-year-old female patient with terminal ileum Crohn’s disease and ankylosing spondylitis presented with recurrent angioedema and urticaria. Investigations ruled out hereditary angioedema, and environmental or food allergen triggers. She was diagnosed with chronic idiopathic urticaria with angioedema, and was treated with a trial of intravenous immunoglobulin immunotherapy, danazol, prednisone and hydroxyzine. Due to ongoing bowel and arthritic complaints, she was started on infliximab infusions and within 2 treatments, she had complete resolution of the angioedema and urticaria, as well as of the bowel and arthritic symptoms. Unfortunately she developed allergic reactions to the infliximab and was switched to another anti-tumor necrosis factor (TNF)-α agent, adalimumab. Since then, she has had no further angioedema or urticaria, and her Crohn’s disease has been quiescent. This is the first known case report of chronic idiopathic urticaria with angioedema coexistent with Crohn’s disease that was successfully treated with anti-TNF-α agents.

Modulation of inflammatory gene expression by a bilberry ( Vaccinium myrtillus L.) extract and single anthocyanins considering their limited stability under cell culture conditions

Studies with nonintestinal models indicate that anthocyanin-rich extracts can modulate inflammatory gene expression and may help prevent development of inflammatory bowel diseases (IBD). This work investigated the influence of a bilberry ( Vaccinium myrtillus L.) extract (BE) and comprising anthocyanins on pro-inflammatory genes in IFN-γ/IL-1β/TNF-α stimulated human colon epithelial cells (T84) by qRT-PCR and cytokine arrays. Moreover, the stability of selected anthocyanins under cell culture conditions was examined to assess their anti-inflammatory properties. BE and single anthocyanins significantly inhibited the expression and secretion of IBD-associated pro-inflammatory mediators (TNF-α, IP-10, I-TAC, sICAM-1, GRO-α) in the stimulated cells. The anti-inflammatory activity thereby strongly depends on the aglycon structure (hydroxylation and methylation pattern) and the sugar moiety. In contrast to anthocyanidins, which were highly unstable in cell culture medium, suggesting that their degradation products might contribute to the inhibitory effects assigned to the parent compounds, anthocyanins have higher stability and may directly contribute to BE's effects.

Anti-inflammatory effects of urocanic Acid derivatives in models ex vivo and in vivo of inflammatory bowel disease

Urocanic acid (UCA) derivatives were tested for their anti-inflammatory activity in inflammatory bowel disease (IBD) in two models: ex vivo and an experimental mouse model. Ex vivo: inflamed colonic tissue was incubated in culture medium with or without the UCA derivatives. Biopsies, incubated with UCA derivatives, produced lower levels of proinflammatory cytokines IL-6 and IL-8 as compared to control biopsies. The same compounds also showed increased levels of IL-10, providing an additional indication for anti-inflammatory properties. In vivo: a combination of two imidazoles and a combination of two of their ethyl esters were administered to mice while colitis was induced by oral administration of dextran sodium sulfate (DSS). Some parameters did not show conclusive effects, but the imidazoles and their ethyl esters reduced the area of inflammation and the number of infiltrating neutrophils. Fibrosis and the sum of all histological aspects were reduced by the imidazoles, whereas the ethyl esters reduced the colon weight to length ratio. These results suggest that the UCA derivatives have anti-inflammatory effect on IBD. In addition, fine tuning of the ex vivo model may provide an elegant way to predict anti-inflammatory effects of potential drugs in humans, which may decrease the need for animal experiments.

Increased expression of interleukin-32 in the inflamed ileum of ankylosing spondylitis patients

OBJECTIVE

To study the mRNA expression and protein tissue distribution of IL-32 in ileal biopsy specimens from patients with AS.

METHODS

Quantitative gene expression analysis, by real-time PCR, of IL-32, IL-1β, IL-10, TNF-α and IFN-γ was performed on ileal biopsies of 15 AS and 15 Crohn's disease (CD) patients and 10 healthy subjects (HSs). IL-32 tissue distribution was evaluated by immunohistochemistry. The effect of IL-32 on the production of IL-10 by intestinal epithelial cell lines was also evaluated.

RESULTS

In the ileal specimens of patients with AS and intestinal chronic inflammation, significant up-regulation of IL-32 at both the mRNA and protein levels was found as compared with non-inflamed AS patients and controls. IL-32 over-expression in AS was accompanied by a significant increase of IL-10 but not of cytokines involved in IL-32 induction. IL-32 stimulates intestinal epithelial cell lines in vitro to produce IL-10.

CONCLUSION

Our findings suggest IL-32 as an important cytokine probably involved in the innate immune response occurring in early phases of intestinal inflammation, where it seems to play a prevalent protective role.

Expression of IL-17 in inflammatory bowel disease and synergistic action of IL-17 and LPS on IL-8 expression in intestinal epithelial cells

AIM: To investigate the expression of interleukin-17 (IL-17) in inflammatory bowel disease (IBD) in a mouse model and to examine the synergistic reaction of IL-17 and lipopolysaccharide (LPS) on interleukin-8 (IL-8) expression in intestinal epithelial cells (HT-29 cells).

METHODS: A mouse model of inflammatory bowel disease was induced with TNBS to detect the expression of IL-17 and its receptor IL-17Ra in IBD. HT-29 cells were treated with IL-17 and/or different concentrations of LPS to examine their synergistic action on the expression of IL-8 mRNA and protein by FACS, real-time PCR, ELISA, and Western blot.

RESULTS: The expression of IL-17 and IL-17Ra in IBD was significantly increased (both P < 0.05). IL-17 and low doses of LPS showed a synergistic action on IL-8 expression in HT-29 cells (2187.61 ± 132.42 vs 2634.27 ± 134.63, P = 0.01) by activating NF-κB and promoting inflammation. However, high doses of LPS reduced the levels of IL-8, and their synergistic action with IL-17 disappeared (1841.43 ± 50.38 vs 1685.67 ± 71.47, P = 0.03).

CONCLUSION: IL-17 has a synergistic action with low, but not high doses of LPS on the expression of inflammatory mediators in HT-29 cells.

Partial replacement of ω-6 fatty acids with medium-chain triglycerides, but not olive oil, improves colon cytokine response and damage in experimental colitis

BACKGROUND

Soybean oil is rich in ω-6 fatty acids, which are associated with higher incidence and more severe cases of inflammatory bowel diseases. The authors evaluated whether partial replacement of soybean oil by medium-chain triglycerides (MCTs) or olive oil influenced the incidence and severity of experimental ulcerative colitis by using different parenteral lipid emulsions (LEs).

METHODS

Wistar rats (n = 40) were randomized to receive parenteral infusion of the following LE: 100% soybean oil (SO), 50% MCT mixed with 50% soybean oil (MCT/SO), 80% olive oil mixed with 20% soybean oil (OO/SO), or saline (CC). After 72 hours of infusion, acetic acid experimental colitis was induced. After 24 hours, colon histology and cytokine expression were analyzed.

RESULTS

SO was not significantly associated with overall tissue damage. MCT/SO was not associated with necrosis (P < .005), whereas OO/SO had higher frequencies of ulcer and necrosis (P < .005). SO was associated with increased expression of interferon-γ (P = .005) and OO/SO with increased interleukin (IL)-6 and decreased tumor necrosis factor-α expression (P < .05). MCT/SO appeared to decrease IL-1 (P < .05) and increase IL-4 (P < .001) expression.

CONCLUSIONS

Parenteral SO with high concentration of ω-6 fatty acids was not associated with greater tissue damage in experimental colitis. SO partial replacement with MCT/SO decreased the frequency of histological necrosis and favorably modulated cytokine expression in the colon; however, replacement with OO/SO had unfavorable effects.

Signaling by IL-31 and functional consequences

Cytokines are key to control cellular communication. Interleukin-31 (IL-31) was recently discovered as a new member of the IL-6 family of cytokines. IL-31 signals through a heterodimeric receptor composed of OSMR and IL-31RA, a complex that stimulates the JAK-STAT, the RAS/ERK and the PI3K/AKT signal transduction pathways. The available data suggests that IL-31 is important for both innate and adaptive immunity in tissues that are in close contact with the environment, i.e. the skin, the airways and the lung, and the lining of the intestine. Enhanced expression of IL-31 is associated with a number of diseases, including pruritic diseases such as atopic dermatitis, but also in allergy and inflammatory bowel disease. In these tissues IL-31 coordinates the interaction of different immune cells, including T-cells, mast cells, and eosinophils, with epithelial cells. In this review we have summarized the available data on IL-31 and its receptor, their expression pattern and how they are regulated. We describe the current state of knowledge of the involvement of IL-31 in diseases, both in humans and in mouse models. From these studies it is becoming clear that IL-31 plays an important role in the proper functioning of the skin and of airway and intestinal epithelia. The findings available suggest that IL-31 might be an interesting target for directed drug therapy.

Significance of RhoC and IQGAP1 expression in hepatocellular carcinoma

AIM: To detect the expression of RhoC and IQGAP1 proteins in hepatocellular carcinoma (HCC) and to analyze their clinicopathological significance.

METHODS: The expression of RhoC and IQGAP1 proteins was detected by immunohistochemistry in 56 HCC specimens and 15 normal liver specimens. The association of RhoC and IQGAP1 protein expression with clinicopathologicalparamters was analyzed.

RESULTS: The positive rates of RhoC and IQGAP1 expression were significantly higher in HCC than in normal liver tissue (66% vs 20%; 75% vs 13%, both P < 0.05). The expression of RhoC and IQGAP1 proteins was related to tumor differentiation and invasion in HCC (both P < 0.05). A positive correlation was noted between the expression of RhoC and that of IQGAP1 in HCC(r = 0.631, P < 0.05).

CONCLUSION: RhoC and IQGAP1 play significant roles in promoting the progression of HCC. Expression of RhoC and IQGAP1 can be used as useful parameters for clinical assessment of biological behavior and prognosis of HCC.

Treatment of murine colitis with IL-10-secreting Escherichia coli

AIM: To evaluate the therapeutic effect of interleukin-10 (IL-10)-secreting Escherichia coli (E. coli) on murine colitis.

METHODS: Sixty 6-8-wk-old female BALB/c mice were divided into six groups: normal control group, dextran sulfate sodium (DSS) group, empty plasmid-transformed E.coli (E.coli0) group, IL-10 gene-transformed E.coli (E.coli/mIL-10) group, DSS + E.coli0 group, and DSS + E.coli/mIL-10 group. The DSS, DSS + E.coli0, and DSS + E.coli/mIL-10 groups were fed 5 % DSS solution for 7 d to induce colitis, while the other groups were given normal tap water. The E.coli0 and DSS + E.coli0 groups were intragastrically given E.coli0; the E.coli/mIL-10 and DSS + E.coli/mIL-10 groups were given recombinant E.coli/mIL-10; and the DSS and normal control groups were given LB (Luria-Bertain) medium. The treatment lasted for 8 days. Disease activity index (DAI) was recorded each day. The expression of TNF-α, NF-κB p65 and myeloperoxidase (MPO) in the colon was measured at the end of the experiment.

RESULTS: Mice in the DSS + E.coli/mIL-10 group showed a lower DAI than those in the DSS and DSS + E.coli0 groups from day 4 to the end of the experiment. The levels of TNF-α and MPO in the colon and the expression of NF-κB P65 in the nuclei of inflammatory cells were lower in the DSS + E.coli/mIL-10 group (172.46 pg/g ± 22.23 pg/g, 2.35 U/g ± 0.15 U/g) than in the DSS (237.85 pg/g ± 14.86 pg/g, 4.15 U/g ± 0.29 U/g) and DSS + E.coli0 groups (239.81 pg/g ± 50.38 pg/g, 3.5 U/g ±1.23 U/g) at the end of experiment. No colonic injury was observed in mice in the normal control, E.coli/IL-10 and E.coli0 groups.

CONCLUSION: Local delivery of IL-10 gene-transformed E.coli ameliorates DSS-inducd murine colitis possibly by decreasing proinflammatory cytokine production and inhibiting NF-κB activation. Gene therapy strategies using engineered E.coli encoding immunoregulatory cytokines may provide a potential approach for treatment of inflammatory bowel disease.

Allergic inflammation: role of cytokines with special emphasis on IL-4

This review examines recent articles on the relationship of cytokines to allergy and inflammation with particular emphasis on interleukin (IL)-4. The objective of this article is therefore to review published studies to identify cytokines consistently involved in allergic inflammation. Proinflammatory cytokines, including IL-4, IL-5, IL-13 and GM-CSF along with TNF-alpha play a role in allergen-induced airway leukocyte recruitment and these cytokines can be generated by T mast cells and other cells. In addition, IL-9, IL-25, IL-33, IL-17, IL-27 and IFN-gamma are deeply involved in the regulation of asthma. Blocking the effect of these proinflammatory cytokines might provide new therapeutic approaches for the control of allergy and inflammation.

Adalimumab as second line anti-tumour necrosis factor alpha therapy for Crohn's disease: A single centre experience

BACKGROUND AND AIMS

Non-response, loss of response, or intolerance to anti-tumour necrosis factor alpha (anti-TNFα) therapy is well recognised in Crohn's disease (CD) patients. Data concerning outcomes following the use of a second anti-TNFα therapy, particularly in patients who do not respond to a first anti-TNFα agent, are still emerging. The aim of this study was to assess response and tolerability to adalimumab following infliximab failure in a single centre cohort of CD patients.

METHODS

Data were collected prospectively on 44 patients who received adalimumab therapy following infliximab failure. Initial response to adalimumab therapy at 6weeks following induction was defined using a two point decrease in the Harvey-Bradshaw Index, with remission at this point defined using a Harvey Bradshaw index≤4. Sustained clinical benefit at the last point of follow up was determined using a physician's global assessment. Corticosteroid-free sustained clinical benefit was also assessed at this point.

RESULTS

Thirty-four (77%) patients had initial response to adalimumab therapy, with 28 (64%) having sustained clinical benefit. Corticosteroid-free sustained clinical benefit was achieved in nine (53%) of 17 patients requiring steroids at commencement of adalimumab. Four (44%) of the 9 patients who were primary non-responders to infliximab responded to adalimumab. The majority of CD patients who failed adalimumab therapy required surgery.

CONCLUSIONS

Second-line anti-TNFα therapy with adalimumab is effective at both inducing remission and maintaining response in CD patients who have failed infliximab, regardless of the reason for infliximab failure.

Gene expression profiling and response signatures associated with differential responses to infliximab treatment in ulcerative colitis

OBJECTIVES

Infliximab has been shown to induce clinical response and remission in ulcerative colitis (UC). To characterize the biological response of patients to infliximab, we analyzed the mRNA expression patterns of mucosal colonic biopsies taken from UC patients enrolled in the Active Ulcerative Colitis Trial 1 (ACT1) study.

METHODS

Biopsies were obtained from 48 UC patients before treatment with 5 or 10 mg/kg infliximab, and at 8 and 30 weeks after treatment (n = 113 biopsies). Global gene expression profiling was performed using Affimetrix GeneChip Human Genome U133 Plus 2.0 arrays. Expression profiling results for selected genes were confirmed using qPCR.

RESULTS

Infliximab had a significant effect on mRNA expression in treatment responders, with both infliximab dose and duration of treatment having an effect. Genes affected are primarily involved with inflammatory response, cell-mediated immune responses, and cell-to-cell signaling. Unlike responders, non-responders do not effectively modulate T(H₁), T(H₂), and T(H₁₇) pathways. Gene expression can differentiate placebo and infliximab responders.

CONCLUSIONS

Analysis of mRNA expression in mucosal biopsies following infliximab treatment provided insight into the response to therapy and molecular mechanisms of non-response.

Involvement of interferon-γ in bowel disease pathogenesis by nitric oxide pathway: a study in Algerian patients

The pathogenesis of inflammatory bowel disease (IBD) is complex, involving a wide range of molecules including cytokines. Abnormalities in the expression of immunoregulatory cytokines such as interferon-γ (IFN-γ) and interleukin-12 (IL-12) may indicate a dysregulation of intestinal immunity probably associated with pathogenic events. The aim of this work was to study the implication of IFN-γ and nitric oxide (NO) in bowel disease pathogenesis. In this study, we investigated the circulating IFN-γ and IL-12 production in 2 groups of Algerian patients with IBD (Crohn's disease and ulcerative colitis). Moreover, systemic NO concentrations and NO generation by colonic mucosa were determined in these patients. Finally, we examined the effect of IFN-γ on NO production by peripheral blood mononuclear cells (PBMCs) of these patients. Our results indicate that IFN-γ/IL-12 production in IBD patients was increased in comparison to healthy donors. This strong production correlates with high levels of NO in sera and colonic mucosa culture. Interestingly, NO production was related to the clinical stage of IBD patients (inactive or active stage). The relationship between IFN-γ and NO production in IBD patients were confirmed by in vitro experiments and the role of IFN-γ in NO synthase induction in patients' PBMC culture was suggested. Collectively, our results show that IFN-γ plays a pivotal role in IBD pathogenesis through NO pathway.

Gut microbiota, probiotics and inflammatory bowel disease

The colonization of humans with commensals is critical for our well-being. This tightly regulated symbiotic relationship depends on the flora and an intact mucosal immune system. A disturbance of either compound can cause intestinal inflammation. This review summarizes extrinsic and intrinsic factors contributing to intestinal dysbiosis and inflammatory bowel disease.

Recent advances in cytokines: therapeutic implications for inflammatory bowel diseases

Inflammatory bowel diseases (IBDs) are complex and chronic disabling conditions resulting from a dysregulated dialogue between intestinal microbiota and components of both the innate and adaptive immune systems. Cytokines are essential mediators between activated immune and non-immune cells, including epithelial and mesenchymal cells. They are immunomodulatory peptides released by numerous cells and these have significant effects on immune function leading to the differentiation and survival of T cells. The physiology of IBD is becoming a very attractive field of research for development of new therapeutic agents. These include cytokines involved in intestinal immune inflammation. This review will focus on mechanisms of action of cytokines involved in IBD and new therapeutic opportunities for these diseases.

Role of thymic stromal lymphopoietin in the pathogenesis of nasal polyposis

INTRODUCTION

Polyposis is an end form of chronic mucosal inflammation in a number of disorders and has an important impact on patient's life quality. Thymic stromal lymphopoietin (TSLP) is involved in many inflammatory processes such as asthma and allergic rhinitis (AR). The aim of this study is to elucidate the role of TSLP in the pathogenesis of polyposis.

METHODS

Ninety-four patients with nasal polyposis (NP) and/or allergic rhinitis (AR) were treated with inferior turbinectomy and polyp resection. Levels of TSLP in the nasal epithelial layer were measured; expression of TSLP receptor and OX40 ligand (OX40L) was assessed in isolated nasal mucosal dendritic cells (DC); tumor necrosis factor (TNF), interleukin (IL)-4 and interferon (IFN)-γ expressions were determined in isolated nasal mucosal CD4(+) T cells.

RESULTS

The levels of TSLP in nasal epithelial layer were higher in the NP group than in the non-NP group. Higher expression of TSLP receptor and OX40L were detected in DCs of NP nasal mucosa. TNF-α(+) IL-4(+)CD4(+) T cells were detected in NP/AR nasal mucosa; TNF(+) IFN-γ(+) CD4(+) T cells were identified in NP/non-AR nasal mucosa. TSLP-primed DCs drove naive CD4(+) T cells to become TNF(+) IL-4(+) CD4(+) T cells, whereas TSLP/lipopolysaccharide-primed DCs induced naive CD4(+) T cells to become TNF(+) IFN-γ(+) T cells.

CONCLUSIONS

The data indicate that TSLP is involved in the pathogenesis of polyposis.

Cytokine Networks in Ulcerative Colitis

Ulcerative colitis (UC) is a relapsing inflammatory bowel disease whose pathogenesis has yet to be defined completely. A genetic predisposition is needed to develop the colitis, but environmental factors are necessary to trigger an exaggerated and aberrant immune response, which stands at the basis of the mucosal healing. Cytokines, small cell-signaling protein molecules secreted by various types of cells including immune and glia cells, are the main mediators of the mucosal healing in IBD; ulcerative colitis is characterized by a Th2 atypical immune response, since, beside the classical proinflammatory cytokines, such as IL-1, IL-6, and TNF-α, in the pathogenesis of UC, we find a complex network in which the Th2 cytokines, IL-10 and IL-13, play a key role, but little IL-4 was found. Our aim was to review the literature to point out the state of the art in terms of cytokines because the knowledge of cytokine network in UC could lead to the discovery of new therapeutical targets.

IL-31 a Th2 cytokine involved in immunity and inflammation

Cytokines are immunal regulatory proteins, however they also play a relevant role in inflammatory diseases. IL-31 is a newly discovered cytokine expressed primarily in TH2 cells, introduced by activated CD4+ T cells. IL-31 is capable of inducing chemokines and other cytokines in several inflammatory diseases via its surface receptor. This cytokine is also produced by mast cells and mast cell line, suggesting a role in allergic diseases. In this editorial we revisit the biological role of IL-31 in immunity and inflammation.

Tumor necrosis factor alpha and inflammation disrupt the polarity complex in intestinal epithelial cells by a posttranslational mechanism

Inflammatory processes disrupt the barrier function in epithelia. Increased permeability often leads to chronic of inflammation. Important among other cytokines, tumor necrosis factor alpha (TNF-α) initiates an NF-κB-mediated response that leads to upregulation of myosin light chain kinase (MLCK), a hallmark of the pathogenesis of inflammatory bowel disease. Here, we found that two components of the evolutionarily conserved organizer of tight junctions and polarity, the polarity complex (atypical protein kinase C [aPKC]-PAR6-PAR3) were downregulated by TNF-α signaling in intestinal epithelial cells and also in vivo during intestinal inflammation. Decreases in aPKC levels were due to decreased chaperoning activity of Hsp70 proteins, with failure of the aPKC rescue machinery, and these effects were rescued by NF-κB inhibition. Comparable downregulation of aPKC shRNA phenocopied effects of TNF-α signaling, including apical nonmuscle myosin II accumulation and myosin light chain phosphorylation. These effects, including ZO-1 downregulation, were rescued by overexpression of constitutively active aPKC. We conclude that this novel mechanism is a complementary effector pathway for TNF-α signaling.

Ulcerative colitis and irritable bowel patients exhibit distinct abnormalities of the gut microbiota

BACKGROUND

Previous studies suggest a link between gut microbiota and the development of ulcerative colitis (UC) and irritable bowel syndrome (IBS). Our aim was to investigate any quantitative differences in faecal bacterial compositions in UC and IBS patients compared to healthy controls, and to identify individual bacterial species that contribute to these differences.

METHODS

Faecal microbiota of 13 UC patients, 11 IBS patients and 22 healthy volunteers were analysed by PCR-Denaturing Gradient Gel Electrophoresis (DGGE) using universal and Bacteroides specific primers. The data obtained were normalized using in-house developed statistical method and interrogated by multivariate approaches. The differentiated bands were excised and identified by sequencing the V3 region of the 16S rRNA genes.

RESULTS

Band profiles revealed that number of predominant faecal bacteria were significantly different between UC, IBS and control group (p < 10-4). By assessing the mean band numbers in UC (37 ± 5) and IBS (39 ± 6), compared to the controls (45 ± 3), a significant decrease in bacterial species is suggested (p = 0.01). There were no significant differences between IBS and UC. Biodiversity of the bacterial species was significantly lower in UC (μ = 2.94, σ = 0.29) and IBS patients (μ = 2.90, σ = 0.38) than controls (μ = 3.25, σ = 0.16; p = 0.01). Moreover, similarity indices revealed greater biological variability of predominant bacteria in UC and IBS compared to the controls (median Dice coefficients 76.1% (IQR 70.9 - 83.1), 73.8% (IQR 67.0 - 77.5) and 82.9% (IQR 79.1 - 86.7) respectively). DNA sequencing of discriminating bands suggest that the presence of Bacteroides vulgatus, B. ovatus, B. uniformis, and Parabacteroides sp. in healthy volunteers distinguishes them from IBS and UC patients. DGGE profiles of Bacteroides species revealed a decrease of Bacteroides community in UC relative to IBS and controls.

CONCLUSION

Molecular profiling of faecal bacteria revealed abnormalities of intestinal microbiota in UC and IBS patients, while different patterns of Bacteroides species loss in particular, were associated with UC and IBS.

Attenuation of TNF-driven murine ileitis by intestinal expression of the viral immunomodulator CrmD

Tumor necrosis factor α (TNFα) is a key pathogenic factor in Crohn's disease and rheumatoid arthritis. TNF(ΔARE) mice express high levels of TNFα and present Crohn's-like ileitis and arthritis. Alterations in the chemokine network could underline the TNF-driven ileitis. The aim of this study was to evaluate the role of TNF and chemokines in ileitis using ectromelia virus cytokine response modifier D (CrmD), a protein that binds TNFα and a limited number of chemokines. We generated transgenic mice expressing CrmD in intestinal epithelial cells (vCrmD mice) and crossed them with the TNF(ΔARE) mice to test whether CrmD could affect TNF-driven inflammatory processes. During homeostasis, only the number of B cells in the lamina propria was reduced by CrmD expression. Interestingly, CrmD expression in the intestine markedly attenuated the inflammatory infiltrates in the ileum of TNF(ΔARE) mice, but did not affect development of arthritis. Our results suggest that CrmD affects development of ileitis by locally affecting both TNF and chemokine function in the ileum.

The inflammatory cytokine tumor necrosis factor modulates the expression of Salmonella typhimurium effector proteins

Tumor necrosis factor alpha (TNF-alpha)is a host inflammatory factor. Bacteria increase TNF-alpha expression in a variety of human diseases including infectious diseases, inflammatory bowel diseases, and cancer. It is unknown, however, how TNF-alpha directly modulates bacterial protein expression during intestinal infection and chronic inflammation. In the current study, we hypothesize that Salmonella typhimurium senses TNF-alpha and show that TNF-alpha treatment modulates Salmonella virulent proteins (called effectors), thus changing the host-bacterial interaction in intestinal epithelial cells. We investigated the expression of 23 Salmonella effectors after TNF-alpha exposure. We found that TNF-alpha treatment led to differential effector expression: effector SipA was increased by TNF-alpha treatment, whereas the expression levels of other effectors, including gogB and spvB, decreased in the presence of TNF-alpha. We verified the protein expression of Salmonella effectors AvrA and SipA by Western blots. Furthermore, we used intestinal epithelial cells as our experimental model to explore the response of human intestinal cells to TNF-alpha pretreated Salmonella. More bacterial invasion was found in host cells colonized with Salmonella strains pretreated with TNF-alpha compared to Salmonella without TNF-alpha treatment. TNF-alpha pretreated Salmonella induced higher proinflammatory JNK signalling responses compared to the Salmonella strains without TNF-alpha exposure. Exposure to TNF-alpha made Salmonella to induce more inflammatory cytokine IL-8 in intestinal epithelial cells. JNK inhibitor treatment was able to suppress the effects of TNF-pretreated-Salmonella in enhancing expressions of phosphorylated-JNK and c-jun and secretion of IL-8. Overall, our study provides new insights into Salmonella-host interactions in intestinal inflammation.

Role of muscarinic receptor activation in regulating immune cell activity in nasal mucosa

BACKGROUND

The prevalence of airway inflammatory disorders keeps rising; its pathogenic mechanism is still not fully understood.

OBJECTIVE

The present study aimed to investigate the role of muscarinic receptor (M receptor) in regulating the immune cell activity in nasal mucosa by using surgical removed nasal mucosa from patients with nasal polyposis (NP) as a study platform.

METHODS

Human nasal mucosal sample was collected from inferior turbinectomy of 86 patients with NP or/and allergic rhinitis. Expression of tumor necrosis factor alpha (TNF-alpha), M receptor, OX40 ligand was measured in nasal mucosa by enzyme-linked immunosorbent assay, flow cytometry, and Western blotting assay.

RESULTS

When compared with non-NP (nNP) nasal mucosa, contents of TNF-alpha and TNF-alpha+ cells markedly increased in NP nasal mucosa; immune staining colocalized M3 receptor+ and TNF-alpha+ cells in NP nasal mucosa; exposure of isolated CD4+ T cells to methacholine induced the release of TNF-alpha. We also found CD11c+/M3 receptor+ cells in NP nasal mucosa. Methacholine increased the expression of OX40L in dendritic cells. Staphylococcal (S) aureus and S. enterotoxin B (SEB) were detected in NP nasal mucosa. Exposure of dendritic cells or naïve CD4+ T cells to SEB initiated the expression of M3 receptor at mRNA and protein levels.

CONCLUSIONS

The present data demonstrate that parasympathetic activity has the capacity to activate dendritic cells to release OX40 ligand, the latter induces CD4+ T cells to produce IL-4 and TNF-alpha that may further contribute to the pathogenesis of NP.

Foxp3+ regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is thought to result from an aberrant immune response. Inflammation in IBD may be caused by the loss of homeostasis between CD4+ CD25high Foxp3+ regulatory cells (Treg) and proinflammatory Th17 cells. The aim of this study was to investigate Treg and Th17 cells in the peripheral blood and intestinal mucosa of IBD patients and to assess the mucosal cytokine environment.

METHODS

Treg and Th17 cells were measured in peripheral blood of 63 IBD patients and 28 controls by flow cytometry. Forkhead box p3 (Foxp3), interleukin (IL)-17a, IL-1beta, IL-6, IL-21, IL-23, and transforming growth factor (TGF)-beta mRNA were analyzed using real-time reverse transcription polymerase chain reaction in intestinal biopsies of 24 IBD and 18 control subjects.

RESULTS

A decrease in Treg and increase in Th17 cells was observed in the peripheral blood of IBD patients. When measured in the same patient and expressed as a ratio, a significant decrease in Treg/Th17 ratio was observed in IBD. Elevated expression of Foxp3, IL-17a, IL-1beta, and IL-6 was observed in the mucosa of IBD patients, while TGF-beta was only elevated in ulcerative colitis.

CONCLUSION

IBD is associated with a reduced ratio of Treg to Th17 cells in peripheral blood and is characterized by a proinflammatory cytokine microenvironment, which supports the continued generation of Th17 cells.

Foxp3+ regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is thought to result from an aberrant immune response. Inflammation in IBD may be caused by the loss of homeostasis between CD4+ CD25high Foxp3+ regulatory cells (Treg) and proinflammatory Th17 cells. The aim of this study was to investigate Treg and Th17 cells in the peripheral blood and intestinal mucosa of IBD patients and to assess the mucosal cytokine environment.

METHODS

Treg and Th17 cells were measured in peripheral blood of 63 IBD patients and 28 controls by flow cytometry. Forkhead box p3 (Foxp3), interleukin (IL)-17a, IL-1beta, IL-6, IL-21, IL-23, and transforming growth factor (TGF)-beta mRNA were analyzed using real-time reverse transcription polymerase chain reaction in intestinal biopsies of 24 IBD and 18 control subjects.

RESULTS

A decrease in Treg and increase in Th17 cells was observed in the peripheral blood of IBD patients. When measured in the same patient and expressed as a ratio, a significant decrease in Treg/Th17 ratio was observed in IBD. Elevated expression of Foxp3, IL-17a, IL-1beta, and IL-6 was observed in the mucosa of IBD patients, while TGF-beta was only elevated in ulcerative colitis.

CONCLUSION

IBD is associated with a reduced ratio of Treg to Th17 cells in peripheral blood and is characterized by a proinflammatory cytokine microenvironment, which supports the continued generation of Th17 cells.

Kinoids: a family of immunogens for active anticytokine immunotherapy applied to autoimmune diseases and cancer

The complex homeostasis of tissues is coordinated by the cytokine network and imbalances in this network may result in chronic immune disorders. Key specific cytokines, such as TNF-α, IFN-α, IL-4 or VEGF have been demonstrated to be overproduced or abnormally released in the microenvironment of pathologic tissues. These findings have opened up the way to passive immunotherapy with anticytokine monoclonal antibodies. Even though passive immunotherapy has proved to be efficient, it is hampered by specific limitations. The discovery of a family of immunogens, the kinoids, consisting of inactivated cytokine derivatives, has led some to propose them for active immunotherapy as an alternative to passive immunotherapy. This review focuses on kinoids – on their validation in experimental mouse models and ongoing clinical trials. The advantages offered by this active immune therapy in terms of efficacy, safety and patient compliance will be stressed.

Influence of apple polyphenols on inflammatory gene expression

Apples (Malus spp., Rosaceae) and products thereof contain high amounts of polyphenols which show diverse biological activities and may contribute to beneficial health effects, like protecting the intestine against inflammation initiated by chronic inflammatory bowel diseases (IBD). IBD are characterized by an excessive release of several proinflammatory cytokines and chemokines by different cell types which results consequently in an increased inflammatory response. In the present study we investigated the preventive effectiveness of polyphenolic juice extracts and single major constituents on inflammatory gene expression in immunorelevant human cell lines (DLD-1, T84, MonoMac6, Jurkat) induced with specific stimuli. Besides the influence on proinflammatory gene expression, the effect on NF-kappaB-, IP-10-, IL-8-promoter-, STAT1-dependent signal transduction, and the relative protein levels of multiple released cytokines and chemokines were studied. DNA microarray analysis of several genes known to be strongly regulated during gastrointestinal inflammation, combined with quantitative real-time PCR (qRT-PCR) revealed that the apple juice extract AE04 (100-200 microg/mL) significantly inhibited the expression of NF-kappaB regulated proinflammatory genes (TNF-alpha, IL-1beta, CXCL9, CXCL10), inflammatory relevant enzymes (COX-2, CYP3A4), and transcription factors (STAT1, IRF1) in LPS/IFN-gamma stimulated MonoMac6 cells without significant effects on the expression of house-keeping genes. A screening of some major compounds of AE04 revealed that the flavan-3-ol dimer procyanidin B(2 )is mainly responsible for the anti-inflammatory activity of AE04. Furthermore, the dihydrochalcone aglycone phloretin and the dimeric flavan-3-ol procyanidin B(1 )significantly inhibited proinflammatory gene expression and repressed NF-kappaB-, IP-10-, IL-8-promoter-, and STAT1-dependent signal transduction in a dose-dependent manner. The influence on proinflammatory gene expression by the applied polyphenols thereby strongly correlated with the increased protein levels investigated by human cytokine array studies. In summary, we evaluated selected compounds responsible for the anti-inflammatory activity of AE04. In particular, procyanidin B(1), procyanidin B(2), and phloretin revealed anti-inflammatory activities in vitro and therefore may serve as transcription-based inhibitors of proinflammatory gene expression.

Molecular modulation of intestinal epithelial barrier: contribution of microbiota

The daunting task required of the gut-barrier to prevent luminal pathogens and harmful substances from entering into the internal milieu and yet promoting digestion and absorption of nutrients requires an exquisite degree of coordination between the different architectural units of this barrier. The complex integration and execution of these functions are superbly carried out by the intestinal mucosal (IM) surface. Exposed to trillions of luminal microbes, the IM averts threats by signaling to the innate immune system, through pattern recognition receptors (PRR), to respond to the commensal bacteria by developing tolerance (hyporesponsiveness) towards them. This system also acts by protecting against pathogens by elaborating and releasing protective peptides, cytokines, chemokines, and phagocytic cells. The IM is constantly sampling luminal contents and making molecular adjustments at its frontier. This article describes the topography of the IM and the mechanisms of molecular adjustments that protect the internal milieu, and also describes the role of the microbiota in achieving this goal.

The increased mucosal mRNA expressions of complement C3 and interleukin-17 in inflammatory bowel disease

Recent studies have demonstrated that the complement system participates in the regulation of T cell functions. To address the local biosynthesis of complement components in inflammatory bowel disease (IBD) mucosa, we investigated C3 and interleukin (IL)-17 mRNA expression in mucosal samples obtained from patients with IBD. The molecular mechanisms underlying C3 induction were investigated in human colonic subepithelial myofibroblasts (SEMFs). IL-17 and C3 mRNA expressions in the IBD mucosa were evaluated by real-time polymerase chain reaction. The C3 levels in the supernatant were determined by enzyme-linked immunosorbent assay. IL-17 and C3 mRNA expressions were elevated significantly in the active lesions from ulcerative colitis (UC) and Crohn's disease (CD) patients. There was a significant positive correlation between IL-17 and C3 mRNA expression in the IBD mucosa. IL-17 stimulated a dose- and time-dependent increase in C3 mRNA expression and C3 secretion in colonic SEMFs. The C3 molecules secreted by colonic SEMFs were a 115-kDa alpha-chain linked to a 70-kDa beta-chain by disulphide bonds, which was identical to serum C3. The IL-17-induced C3 mRNA expression was blocked by p42/44 mitogen-activated protein kinase (MAPK) inhibitors (PD98059 and U0216) and a p38 MAPK inhibitor (SB203580). Furthermore, IL-17-induced C3 mRNA expression was inhibited by an adenovirus containing a stable mutant form of I kappaB alpha. C3 and IL-17 mRNA expressions are enhanced, with a strong correlation, in the inflamed mucosa of IBD patients. Part of these clinical findings was considered to be mediated by the colonic SEMF response to IL-17.

[Chronic inflammatory intestinal diseases. Pathophysiology and therapy]

The pathogenesis and therapy of chronic inflammatory intestinal diseases are characterized by an obvious discrepancy. There is extensive agreement that the pathogenesis is substantially based on a disruption of the barrier of the intestinal mucous membrane against luminal bacteria. This has been demonstrated in recent years by evidence from various disciplines, in particular from genetics, microbiology, morphology and innate immunology. However, there is also the evidence-based therapy which, as in the past, is aimed against the effectors of the adaptive immune system. In this case the therapy with biologicals is more aggressive and takes the risk of a series of undesired side-effects. This dichotomy of pathological knowledge and therapeutic innovation is not only medically unsatisfactory but also makes it difficult to present a consistent picture of these symptoms. Despite this an attempt will be made to bridge these inconsistencies and to demonstrate possible future developments which will lead to a final causal therapy. An extended version of this article appears in our newly published book "Colitis ulcerosa und Morbus Crohn".

Activation of nuclear factor-kappaB in dogs with chronic enteropathies

Homeostasis in the intestinal microenvironment between the immune system and luminal antigens appears disturbed in chronic enteropathies. Pro-inflammatory cytokines likely play a role in the pathogenesis of intestinal inflammation. Several inflammatory and immunoregulatory genes have associated nuclear factor-kappaB (NF-kappaB) binding sites, which allow NF-kappaB to regulate gene transcription. The purpose of this study was to investigate (1) the occurrence of NF-kappaB activation during mucosal inflammation in situ, (2) the mucosal distribution pattern of cells expressing activated NF-kappaB within treatment groups, and (3) the effect of specific therapy on NF-kappaB activation. Dogs with chronic enteropathy were studied (n=26) and compared with 13 healthy dogs. Ten dogs had food responsive disease (FRD) and 16 had inflammatory bowel disease (IBD). NF-kappaB activation was detected in duodenal mucosal biopsies using a mouse monoclonal antibody (MAB 3026) that selectively binds the nuclear localization sequence of activated NF-kappaB. To identify macrophages, biopsies were stained using the MAC 387 antibody. Macrophages in the lamina propria double-stained for MAC 387 and NF-kappaB were quantitated; epithelial cell expression of activated NF-kappaB was determined semi-quantitatively. Results showed that more macrophages positive for activated NF-kappaB were present in lamina propria of dogs with chronic enteropathy compared to control dogs (p<0.01). More NF-kappaB positive epithelial cells were observed in FRD dogs compared to IBD dogs (p<0.05). After therapy, the number of macrophages and epithelial cells staining positive for activated NF-kappaB decreased (p<0.01) in chronic enteropathy dogs. In conclusion, activation of NF-kappaB is closely associated with the pathophysiology of canine chronic enteropathy. Down-regulation follows successful therapy.

Pharmacokinetics and safety of single and multiple doses of Asacol tablets in Japanese healthy volunteers

INTRODUCTION

The pharmacokinetics and safety of Asacol (Tillotts Pharma AG, Ziefen, Switzerland), which has been used worldwide to treat ulcerative colitis and Crohn's disease, were studied in Japanese healthy male volunteers.

METHODS

Drug plasma concentrations and urinary and fecal excretions after a single dose (400-4800 mg) and multiple doses (3600 mg/day for 7 days) were investigated.

RESULTS

All adverse events were "not serious." The peak plasma concentration (C max) was reached at 12.3-18.0 hours after a single dose, and the C max and area under the plasma concentration-time curve (AUC) of mesalazine and its N-acetyl metabolite were proportional to the doses. The C max and AUC in non-Japanese subjects reported in the literature were closely correlated to findings in Japanese subjects, and external excretions were also similar in the Japanese and non-Japanese subjects.

CONCLUSIONS

Asacol was safe and well tolerated in this Japanese population, and the non-Japanese clinical data could be extrapolated to the Japanese population.

Immunoregulatory effects of IL-23 on inflammatory bowel disease

IL-23 belongs to IL-12 family and is composed of IL-23 P19 and IL-12 P40 subunits. IL-23 functions through a receptor complex consisting of an IL-12Rβ1 and a specific IL-23R chain in T cells, induces activation of Stat1, Stat3 and Stat4, and triggers T cells to produce IL-10 and INF-γ. Additionally, IL-23 induces the differentiation of native CD4⁺ T cells into highly pathogenic Th17 cells that produce IL-17, IL-6 and TNF-α, and subsequently causes chronic colitis. Recent studies have demonstrated that the IL-23/IL-17 axis plays a critical role in the pathogenesis of inflammatory bowel disease (IBD) and may represent a target for therapeutic intervention for IBD.

l-Tryptophan exhibits therapeutic function in a porcine model of dextran sodium sulfate (DSS)-induced colitis

Conventional therapies for the treatment of inflammatory bowel disease (IBD) have demonstrated limited efficacy and potential toxicity; therefore, there is a need for novel therapies that can safely and effectively treat IBD. Recent evidence has indicated that amino acids may play a role in maintaining gut health. L-tryptophan has been shown to reduce oxidative stress and improve neurological states. The objective of this study was to assess the therapeutic effects of L-tryptophan in a porcine model of dextran sodium sulfate (DSS)-induced colitis. DSS was administered to piglets via intragastric catheter for 5 days followed by tryptophan administration at 80% of the daily recommended intake. The severity of colitis was assessed macroscopically and histopathologically, and intestinal permeability was monitored in vivo by D-mannitol analysis. The effect of tryptophan on the local expression of key mediators of inflammation and IBD pathogenesis was examined at the protein and gene expression levels. Supplementation with tryptophan ameliorated clinical symptoms and improved weight gain to feed intake conversion ratios. Histological scores and measurements were also improved, and gut permeability was notably reduced in tryptophan-supplemented animals. Moreover, tryptophan reduced the expression of the pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin (IL)-6, interferon (IFN)-gamma, IL-12p40, IL-1beta and IL-17, as well as IL-8 and intracellular adhesion molecule-1, and resulted in increased expression of apoptosis initiators caspase-8 and Bax. These results demonstrate that L-tryptophan supplementation can reduce inflammation and enhance the rate of recovery in DSS-induced colitis and may be an effective immunomodulating agent for the treatment of IBD.

Research progress in genetic animal models of inflammatory bowel disease

In inflammatory bowel disease (IBD), experimental models, especially genetic animal models, are known as important tools for detecting potential therapeutic agents and investigating the mechanisms of pathogenesis. This review is intended to cover recent advances in genetic IBD model applications. The models have been classified into two main categories based on the methods of induction: gene knockout (KO) and transgenic.