Spectrum of cytokine gene expression in intestinal mucosal lesions of Crohn's disease and ulcerative colitis

Exploring shared mechanisms between ulcerative colitis and psoriasis and predicting therapeutic natural compounds through bioinformatics and molecular docking

Introduction

Previous studies have suggested a potential correlation between psoriasis (PS) and ulcerative colitis (UC). However, studies exploring the shared mechanisms of both diseases remain limited. Current treatments primarily involve using immunosuppressive drugs, which can lead to potential side effects and drug resistance. Traditional Chinese medicine has demonstrated favorable efficacy in treating UC and PS with fewer side effects. This study aims to elucidate the shared biological mechanisms underlying UC and PS and to predict natural compounds effective for treating both disorders.

Method

We collected and validated differentially expressed genes associated with UC and PS from the Gene Expression Omnibus database. A protein-protein interaction network was constructed using the STRING database, aiding in identifying core targets. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases were utilized to analyze the functions and genomic enrichment of the identified core targets. The CIBERSORT method was employed to assess the correlation of core targets with immune cells. Compounds with potential therapeutic values were selected from the Coremine and TCMSP databases, and their therapeutic efficacy was predicted via molecular docking.

Results

In UC and PS, 20 common core targets were identified, with matrix metalloproteinase 9 (MMP9), matrix metalloproteinase 1 (MMP1), cluster of differentiation 274 (CD274), C-X-C motif chemokine ligand 10 (CXCL10), and topoisomerase II alpha (TOP2A) emerging as the most relevant targets shared between both conditions. Elevated levels of macrophages and dendritic cells were observed in UC and PS, with CXCL10 exhibiting the closest association with macrophages. UC and PS shared common signaling pathways, including IL-17, TNF, and chemokine signaling pathways, among others. Molecular docking revealed that quercetin, baicalen, irisolidone, rutaecarpine, epigallocatechin-3-gallate, and others held potential as natural compounds for treating both disorders.

Conclusion

MMP9, MMP1, and CXCL10, central mediators in the inflammatory pathways of UC and PS, establish a shared mechanism by triggering cytokine and chemokine activation, leading to tissue damage and positioning them as promising therapeutic targets for both conditions. Compounds such as quercetin, luteolin, irisolidone, rutaecarpine, and so on may be key drugs for treating both conditions. These findings suggest the potential advancement of therapeutic strategies and the enhancement of patient care by exploring shared mechanisms and predicting promising natural compounds for treating UC and PS.

Ethanol Extract of Limonium bicolor Improves Dextran Sulfate Sodium-Induced Ulcerative Colitis by Alleviating Inflammation and Restoring Gut Microbiota Dysbiosis in Mice

Ulcerative colitis (UC) is a kind of inflammatory bowel condition characterized by inflammation within the mucous membrane, rectal bleeding, diarrhea, and pain experienced in the abdominal region. Existing medications for UC have limited treatment efficacy and primarily focus on symptom relief. Limonium bicolor (LB), an aquatic traditional Chinese medicine (TCM), exerts multi-targeted therapeutic effects with few side effects and is used to treat anemia and hemostasis. Nevertheless, the impact of LB on UC and its mechanism of action remain unclear. Therefore, the objective of this study was to investigate the anti-inflammatory effects and mechanism of action of ethanol extract of LB (LBE) in lipopolysaccharide-induced RAW 264.7 macrophages and dextran sulfate sodium (DSS)-induced UC. The results showed that LBE suppressed the secretion of cytokines in LPS-stimulated RAW 264.7 cells in a dose-dependent manner. LBE had protective effects against DSS-induced colitis in mice, decreased the disease activity index (DAI) score, alleviated symptoms, increased colon length, and improved histological characteristics, thus having protective effects against DSS-induced colitis in mice. In addition, it reversed disturbances in the abundance of proteobacteria and probiotics such as Lactobacillus and Blautia in mice with DSS-induced UC. Based on the results of network pharmacology analysis, we identified four main compounds in LBE that are associated with five inflammatory genes (Ptgs2, Plg, Ppar-γ, F2, and Gpr35). These results improve comprehension of the biological activity and functionality of LB and may facilitate the development of LB-based compounds for the treatment of UC.

Investigating the association between the tissue expression of miRNA-101, JAK2/STAT3 with TNF-α, IL-6, IL-1β, and IL-10 cytokines in the ulcerative colitis patients

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease caused by numerous factors, such as immune system dysfunction and genetic factors. MicroRNAs (miRNAs) play a crucial role in UC pathogenesis, particularly via the JAK-STAT pathway. Our aim was to investigate the association between miRNA-101 and JAK2-STAT3 signaling pathway with inflammatory cytokines in UC patients.

METHODS

We enrolled 35 UC patients and 35 healthy individuals as the control group, referred to Shariati Hospital, Tehran, Iran. Patients were diagnosed based on clinical, laboratory, histological, and colonoscopy criteria. RNA and protein extracted from tissue samples. Real-time PCR was used to assess the expression levels of miRNA-101, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-10 genes, while western blot was employed to measure levels of P-STAT3, total STAT3, and JAK2 proteins.

RESULTS

Expression of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 significantly increased, while the expression of IL-10 significantly decreased in the case group versus controls. Additionally, miRNA-101 expression was significantly higher in UC patients. A significant correlation between miRNA-101 and IL-6 expression was observed, indicating their relationship and possible impact on cell signaling pathways, JAK2-STAT3. No significant changes were observed in phosphorylated and total STAT3 and JAK2 protein expression.

CONCLUSION

This study provides evidence of increased miRNA-101 expression in UC tissue, suggesting a potential correlation between miRNA-101 and IL-6 expression and their involvement in the JAK2-STAT3 pathway. The study confirms alterations in UC patients' pro-inflammatory cytokines and anti-inflammatory IL-10. However, further investigations are needed to understand the exact role of miRNA-101 in UC pathogenesis fully.

Both Saccharomyces boulardii and Its Postbiotics Alleviate Dextran Sulfate Sodium-Induced Colitis in Mice, Association with Modulating Inflammation and Intestinal Microbiota

OBJECTIVE

To investigate the effect of Saccharomyces boulardii and its freeze-dried and spray-dried postbiotics on the intervention and potential mechanism of dextran sulfate sodium (DSS)-induced ulcerative colitis in mice. [Methods] After the acclimation period of C67BL/6J mice, a colitis model was constructed by applying 2% DSS for 7 d, followed by 7 d of intervention. Subsequently, the disease activity index (DAI), organ index, colon length, colon HE staining of pathological sections, ELISA for blood inflammatory factors (Interleukin (IL)-1β, IL-6, IL-10, Tumor necrosis factor (TNF)-α), Real time quantitative polymerase chain reaction (RT-qPCR) to determine the levels of colonic inflammatory factors (IL-1β, IL-6, IL-10, TNF-α), Occludin gene expression, and intestinal flora were assessed to evaluate the protective effects of S. boulardii and its postbiotics on colitis in mice.

RESULTS

Compared with the DSS group, S. boulardii and the postbiotics interventions effectively improved colonic shortening and tissue damage, increased the expression of intestinal tight junction protein, reduced the secretion of pro-inflammatory factors, increased the secretion of anti-inflammatory factors, and maintained the homeostasis of intestinal microorganisms. Postbiotics intervention is better than probiotics.

CONCLUSIONS

S. boulardii and its postbiotics can effectively alleviate DSS-induced colitis in mice through modulating host immunity and maintaining intestinal homeostasis. Postbiotics are promising next-generation biotherapeutics for ulcerative colitis treatment.

Dietary Application of the Microalga Lobosphaera incisa P127 Reduces Severity of Intestinal Inflammation, Modulates Gut-Associated Gene Expression, and Microbiome in the Zebrafish Model of IBD

SCOPE

Microalgae are an emerging nutritional resource of biomolecules with potential to alleviate gut inflammation. The study explores the anti-inflammatory and immunomodulatory potential of the microalga Lobosphaera incisa P127, which accumulates a rare omega-6 LC-PUFA dihomo-ɣ-linolenic acid (DGLA) under nitrogen starvation. The therapeutic potential of dietary supplementation with P127 is investigated in the zebrafish model of IBD (TNBS-induced colitis).

METHODS AND RESULTS

Guts are sampled from zebrafish fed experimental diets for 4 weeks, before and 24 h after TNBS challenge. Diets containing 15% non-starved (Ns) and 7.5% and 15% N-starved (St) algal biomass significantly attenuate the severity of gut injury and goblet cell depletion. In contrast, diets containing 7.5% Ns and DGLA ethyl ester have no effect on gut condition. Fish fed 15% St, high-DGLA biomass, have the fewest individuals with pathological alterations in the gut. Dietary inclusion of Ns and St distinctly modulates gut-associated expression of the immune and inflammatory genes. Fish fed 15% Ns biomass display a coordinated boost in immune gene expression and show major changes in the gut microbiome prior challenge.

CONCLUSION

Dietary inclusion of L. incisa biomass at two physiological states, ameliorates TNBS-induced gut inflammation, suggesting the synergistic beneficial effects of biomass components not limited to DGLA.

The Effects of Blueberry Phytochemicals on Cell Models of Inflammation and Oxidative Stress

Blueberries have been extensively studied for the health benefits associated with their high phenolic content. The positive impact of blueberry consumption on human health is associated in part with modulation of proinflammatory molecular pathways and oxidative stress. Here, we review in vitro studies examining the anti-inflammatory and antioxidant effects of blueberry phytochemicals, discuss the results in terms of relevance to disease and health, and consider how different blueberry components modulate cellular mechanisms. The dampening effects of blueberry-derived molecules on inflammation and oxidative stress in cell models have been demonstrated through downregulation of the NF-κB pathway and reduction of reactive oxygen species (ROS) and lipid peroxidation. The modulatory effects of blueberry phytochemicals on the mitogen-activated protein kinase (MAPK) pathway and antioxidant system are not as well described, with inconsistent observations reported on immune cells and between models of endothelial, dermal, and ocular inflammation. Although anthocyanins are often reported as being the main bioactive compound in blueberries, no individual phytochemical has emerged as the primary compound when different fractions are compared; rather, an effect of whole blueberry extracts or synergy between different phenolic and nonphenolic extracts seems apparent. The major molecular mechanisms of blueberry phytochemicals are increasingly defined in cell models, but their relevance in more complex human systems needs further investigation using well-controlled clinical trials, in which systemic exposures to blueberry-associated molecules are measured concurrently with physiologic indices of inflammation and oxidative stress.

Suppression of Inflammatory Cytokines Expression with Bitter Melon (Momordica Charantia) in TNBS-instigated Ulcerative Colitis

Background and Objective

This study was aimed to elucidate the molecular mechanism of Momordica charantia (MCh), along with a standard drug prednisolone, in a rat model of colitis induced by trinitrobenzene sulfonic acid (TNBS).

Methods

After the induction of the experimental colitis, the animals were treated with MCh (4 g/kg/day) for 14 consecutive days by intragastric gavage. The colonic tissue expression levels of C-C motif chemokine ligand 17 (CCL-17), interleukin (IL)-1β, IL-6, IL-23, interferon-γ (IFN-γ), nuclear factor kappa B (NF-kB), and tumor necrosis factor-α (TNF-α), were determined at both mRNA and protein levels to estimate the effect of MCh. Besides, colonic specimens were analyzed histopathologically after staining with hematoxylin and eosin.

Results

The body weights from TNBS-instigated colitis rats were found to be significantly lower than untreated animals. Also, the IFN-γ, IL-1β, IL-6, Il-23, TNF-α, CCL-17, and NF-kB mRNA and protein levels were increased significantly from 1.86-4.91-fold and 1.46-5.50-fold, respectively, in the TNBS-instigated colitis group as compared to the control. Both the MCh and prednisolone treatment significantly reduced the bodyweight loss. It also restored the induced colonic tissue levels of IL-1β, IL-6, IFN-γ, and TNF-α to normal levels seen in untreated animals. These results were also supported with the histochemical staining of the colonic tissues from both control and treated animals.

Conclusion

The presented data strongly suggests that MCh has the anti-inflammatory effect that might be modulated through vitamin D metabolism. It is the right candidate for the treatment of UC as an alternative and complementary therapeutics.

Comparison of real-world outcomes of adalimumab and infliximab for patients with ulcerative colitis in the United States

OBJECTIVE

We compared the real-world effectiveness of initiating adalimumab and infliximab among patients in the US who were naïve to tumor necrosis factor (TNF) inhibitors.

METHODS

A retrospective chart review was conducted to evaluate the real-world effectiveness among adults with ulcerative colitis (UC) initiating adalimumab or infliximab. Charts of patients with UC were abstracted by treating physicians (randomly selected from a nationally representative panel) in April 2014. Patient eligibility criteria included: adalimumab or infliximab initiation on/after 1 October 2012; no prior anti-TNF therapy, history of Crohn's disease, or colectomy; and ≥6 months of follow-up. Information on clinical outcomes (partial Mayo score, remission rate, physician global assessment (PGA), stool frequency, and rectal bleeding) and treatment patterns (dose escalations, discontinuations, switches, and treatment augmentations) were retrospectively reported by treating physicians. Kaplan-Meier curves and multivariate Cox proportional hazards regression models were used to assess the time to clinical outcomes and treatment changes for each therapy.

RESULTS

Overall, 170 physicians participated, contributing data on 380 and 424 patients who initiated adalimumab and infliximab, respectively. Baseline clinical characteristics were similar between groups. Both adalimumab- and infliximab-treated patients showed substantial improvements from baseline to follow-up in effectiveness measures; results of these measures were similar between the adalimumab and infliximab cohorts. Time to remission (p = 0.5241), no rectal bleeding (p = 0.7648), normal stool count (p = 0.9941), and normal PGA (p = 0.7697) showed no significant differences between therapies in unadjusted and adjusted comparisons. Unadjusted and adjusted time to event analysis of discontinuation (p = 0.7151), dose escalation (p = 0.6310), treatment augmentation (p = 0.1209), and switching (p = 0.7975) showed no significant differences between the two cohorts.

LIMITATIONS

Retrospective, observational design.

CONCLUSIONS

Adalimumab and infliximab were similarly effective in the treatment of moderate-to-severe UC in the real-world clinical setting.

Anti-inflammatory effect of obestatin and ghrelin in dextran sulfate sodium-induced colitis in rats

BACKGROUND AND OBJECTIVES

Obestatin and ghrelin are hormones derived from the same gene but have opposing effects. Ghrelin has anti-inflammatory activities; however, the role of obestatin in the inflammatory processes has not been clearly demonstrated yet. The aim of the study was to analyse and compare the anti-inflammatory effect of exogenous ghrelin and obestatin in a rat model of colitis.

METHODS

Acute and chronic colitis was induced in 96 rats by adding 3% dextran sulfate sodium to the drinking water for 5 and 10 days, respectively. Intraperitoneal pretreatment with ghrelin or obestatin was started before the induction of colitis, and continued for 5 and 10 days. Clinical signs of the disease and histopathological changes were evaluated. By-products of neutrophil activation, lipid peroxidation, and inflammatory and anti-inflammatory cytokines were measured in colonic tissues.

RESULTS

Obestatin and ghrelin significantly ameliorated clinical and histopathological severity of chronic colitis, whereas they were less effective in the acute form. Therapeutic effect of ghrelin and obestatin in acute colitis was associated with reduced lipid peroxidation and TH1-induced inflammatory response, whereas obestatin in chronic colitis was protective via the suppression of polymorphonuclear leukocyte infiltration and enhancement of glutathione synthesis. Moreover, therapeutic effects of ghrelin and obestatin in chronic colitis appear to be associated with inhibition of inflammatory and activation of anti-inflammatory cytokines.

CONCLUSIONS

This study demonstrated the novel anti-inflammatory effect of obestatin and ghrelin in an experimental model of colitis. Although both obestatin and ghrelin exerted anti-inflammatory effects in chronic colitis, they were less effective in acute colitis.

IL-1RI participates in normal growth plate development and bone modeling

The proinflammatory cytokine interleukin-1 (IL-1) signals through IL-1 receptor type I (IL-1RI) and induces osteoclastogenesis and bone resorption mainly during pathological conditions. Little is known about the effect of excess or absence of IL-1 signaling on the physiological development of the growth plate and bone. In this study, we examine growth plate morphology, bone structure, and mechanical properties as well as osteoclast number in IL-1RI knockout mice to evaluate the role of IL-1RI in the normal development of the growth plate and bone. We show for the first time that IL-1RI knockout mice have narrower growth plates due to a smaller hypertrophic zone, suggesting a role for this cytokine in hypertrophic differentiation, together with higher proteoglycan content. The bones of theses mice exhibit higher trabecular and cortical mass, increased mineral density, and superior mechanical properties. In addition, IL-1RI knockout mice have significantly reduced osteoclast numbers in the chondro-osseous junction, trabecular bone, and cortical bone. These results suggest that IL-1RI is involved in normal growth plate development and ECM homeostasis and that it is significant in the physiological process of bone modeling.

Interleukin-1β promotes proliferation and inhibits differentiation of chondrocytes through a mechanism involving down-regulation of FGFR-3 and p21

The proinflammatory cytokine IL-1β is elevated in many childhood chronic inflammatory diseases as well as obesity and can be associated with growth retardation. Here we show that IL-1β affects bone growth by directly disturbing the normal sequence of events in the growth plate, resulting in increased proliferation and widening of the proliferative zone, whereas the hypertrophic zone becomes disorganized, with impaired matrix structure and increased apoptosis and osteoclast activity. This was also evident in vitro: IL-1β increased proliferation and caused a G1-to-S phase shift in the cell cycle in ATDC5 chondrocytes, accompanied by a reduction in fibroblast growth factor receptor-3 (FGFR-3) and its downstream gene, the cell-cycle inhibitor p21 and its family member p57, whereas the cell-cycle promoter E2F-2 was increased. The reduction in FGFR-3, p21, and p57 was followed by delayed cell differentiation, manifested by decreases in proteoglycan synthesis, mineralization, alkaline phosphatase activity, and the expression of Sox9, RunX2, collagen type II, collagen type X, and other matrix proteins. Taken together, we suggest that IL-1β alters normal chondrogenesis and bone growth through a mechanism involving down-regulation of FGFR-3 and p21.

Functionally enhanced siRNA targeting TNFα attenuates DSS-induced colitis and TLR-mediated immunostimulation in mice

Tumor necrosis factor (TNFα) is a proinflammatory cytokine involved in the pathogenesis of inflammatory bowel disease (IBD). Although TNFα has been extensively targeted using systemic drugs, the use of antisense and small interfering RNA (siRNA) to drive down its expression at the site of inflammation should provide important advantages. In this study, native and chemically modified siRNA against TNFα was developed and characterized using a murine model of IBD. siRNA with 2'-O-methyl and propanediol modifications (siTNF-OMe-P) were resistant to nuclease degradation and provided better silencing efficacy in vitro as compared to unmodified siRNA. Every modification reduced nonspecific Toll-like receptor (TLR)-mediated immunomodulation in human peripheral blood mononuclear cells (PBMC) cells. Intrarectal administration of siTNF-OMe-P significantly ameliorated the clinical endpoints and histopathological severity in 5% dextran sulphate sodium (DSS)-treated mice as compared to unmodified and other chemically modified siRNAs. Differential gene expression assessed in siTNF-OMe-P-treated animals correlated with improved colon integrity and reduced TLR activation as compared to all treatment groups. All in all, this study demonstrates that propanediol and 2'-O-methyl modifications have profound functional consequences for siRNA efficacy in vivo. Consequently, this strategy has potential implications for therapeutic intervention in IBD and other diseases.

Xanthorrhizol attenuates dextran sulfate sodium-induced colitis via the modulation of the expression of inflammatory genes in mice

AIMS

The aim of this study was to investigate the effects of xanthorrhizol (5-(1,5-dimethyl-4-hexenyl)-2-methylphenol, XA) in a mouse model of dextran sulfate sodium (DSS)-induced colitis.

MAIN METHODS

Experimental colitis was induced by exposing male BALB/c mice to 5% DSS in drinking water for 7days. XA (10 or 100mg/kg) was administered orally once a day, together with the DSS. We evaluated body weight, colon length, histological changes, and myeloperoxidase (MPO) activity. A cDNA microarray was used to assess the gene expression profiles that were affected by XA and DSS treatment and a co-citation analysis was used to examine the biological relationship between XA-responsive genes and colitis.

KEY FINDINGS

Decreased body weight, shortened colon length, and damaged colon were observed in the group that was exposed to DSS. Oral administration of XA (10 or 100mg/kg) rescued these symptomatic and histopathological features. The DSS-induced increase in MPO activity, which was used as an index of neutrophil infiltration, was significantly decreased after treatment with XA. Microarray analysis revealed that XA treatment regulated the expression of 34 genes that were altered by exposure to DSS, and that these XA-responsive genes were associated with colonic inflammation. Furthermore, co-citation analysis and graphing of XA-responsive genes revealed a network associated with the gene that encodes for MPO.

SIGNIFICANCE

These results suggest that XA attenuates acute DSS-induced colitis, possibly by modulating the expression of genes mostly associated with colonic inflammation.

Methylene chloride fraction of the leaves of Thuja orientalis inhibits in vitro inflammatory biomarkers by blocking NF-κB and p38 MAPK signaling and protects mice from lethal endotoxemia

AIM OF THE STUDY

Thuja orientalis (TO) has been a recognized herbal medicine across Northeast Asian countries for thousands of years and used for the treatment of various inflammatory diseases through as yet undefined mechanisms. In this study, we set out to determine whether the anti-inflammatory effects of this plant are mediated to suppress mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) activation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells.

MATERIALS AND METHODS

RAW 264.7 cells were pretreated with the methylene chloride fraction of TO (MTO) and stimulated with LPS. Nitric oxide (NO) release was determined by the accumulation of nitrite in the culture supernatants and tumor necrosis factor-α (TNF-α) and IL-6 secretion were determined by immunoenzymatic assay. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression were evaluated via RT-PCR and Western blotting. NF-κB activation was also evaluated by reporter gene assay and electrophoretic mobility shift assay (EMSA). In addition, the protective effect of MTO was evaluated by use of the LPS-induced endotoxin shock model in mice.

RESULTS

We found that MTO significantly suppressed LPS-stimulated NO and IL-6 production without affecting cell viability. MTO inhibited the expression of LPS-induced iNOS and COX-2 protein and their mRNA expression. Also, TNF-α and IL-6 secretion were decreased by MTO in both PMA and ionomycin-stimulated splenocytes. As a result, MTO inhibited pro-inflammatory cytokines such as TNF-α and IL-6, which is hypothesized as being due to the suppression of LPS-induced p38 MAPK and NF-κB activation. Moreover, MTO improved the survival rate during lethal endotoxemia by inhibiting the production of TNF-α in an animal model and our LC-MS analysis showed that a major component of MTO was pinusolide.

CONCLUSIONS

We demonstrate here the evidence that the methylene chloride fraction of Thuja orientalis (MTO) potentially inhibits the biomarkers related to inflammation in vitro and in vivo, and might be provided as a potential candidate for the treatment of inflammatory diseases.

Higher levels of CCL20 expression on peripheral blood mononuclear cells of chinese patients with inflammatory bowel disease

This study aimed at characterizing the levels of CCL20 mRNA transcripts in peripheral mononuclear blood cells (PMBC) of 56 Chinese patients with inflammatory bowel disease (IBD), 30 other intestinal diseases and 30 healthy controls by quantitative real time polymerase chain reaction. The levels of CCL20 mRNA transcripts in PBMC of patients with IBD were significantly higher than that of patients with non-IBD intestinal diseases and healthy controls (p < 0.01) and the CCL20 expression in active IBD patients was significantly higher than that in remission patients (p < 0.01). Importantly, the levels of CCL20 expression in PBMC were significantly correlated with the degrees of disease severity, the levels of erythrocyte sedimentation rate and C-reaction protein, but not hemoglobin, in patients with IBD (p < 0.01). Furthermore, the levels of CCL20 expression in active IBD patients after treatment with salazosulphapyridine or prednisone were significantly reduced, as compared with before treatment (p < 0.01). Therefore, analysis of CCL20 expression in PBMC may be used as a surrogate measure for evaluation of IBD activity, disease progression and therapeutic efficacy in Chinese IBD patients.

Expression of interleukin 6 in brain and colon of rats with TNBS-induced colitis

AIM: To characterise expression of interleukin 6 (IL-6), a potent proinflammatory cytokine, in the occurrence and development of inflammatory bowel disease (IBD) and investigate its effect on neuroimmunomodulation and immune homeostasis regulation.

METHODS: In this study, rats with colitis induced by trinitrobenzene sulfonic acid (TNBS) were sacrificed on days 3, 7, 14, 21 and 28 after induction. In the controls, the TNBS was just replaced by equivalent amount of phosphate buffered solution (PBS, 0.01 mol/L). IL-6 mRNA expression in brain and colon tissues in each phase was evaluated by real-time reverse transcription-polymerase chain reaction, and cellular localisation and protein level of IL-6 was determined by immunohistochemistry.

RESULTS: At day 7, mRNA expression of IL-6 was significantly higher in the colon and brain of IBD rats than that of the controls. The protein level was also significantly higher in colon, hypothalamus and cerebral cortex of IBD rats compared with the controls. So there are similar temporal trends in IL-6 mRNA expression and protein levels in all positions with a persistent increase to a peak at day 7, followed by a decline and gradual return to normal levels.

CONCLUSION: These results revealed that changes in IL-6 expression in brain and colon tissues occur in different phases of IBD. Therefore, we propose that the nerve centre regulates and controls the occurrence and development of IBD via IL-6.

Cytokine signal regulation and autoimmune disorders

Understanding of biological activities of cytokines and exquisite mechanism to regulate their functions has facilitated the therapeutic concept to restore the disequilibrium between pro-inflammatory cytokines and anti-inflammatory cytokines or cytokine inhibitors in some autoimmune inflammatory diseases such as rheumatoid arthritis (RA) and Crohn's disease. The application of molecular biology techniques to design monoclonal antibodies, soluble receptors, or receptor antagonists as therapeutic biologic agents made it possible to regulate the cytokine signals for the treatment of the diseases refractory to conventional therapies. Japanese researchers have contributed considerably to the establishment of cytokine signal regulation in autoimmune diseases. In this article, Japanese studies of cytokine signal regulation, particularly for Interleukin-6 (IL-6) in autoimmune diseases are reviewed.

Ursodeoxycholic acid versus sulfasalazine in colitis-related colon carcinogenesis in mice

PURPOSE

Inflammation influences carcinogenesis. In the current study, we investigated whether ursodeoxycholic acid (UDCA) can inhibit colitis-related mouse colon carcinogenesis and compared it with the effects of sulfasalazine.

EXPERIMENTAL DESIGN

Male CD-1 mice were given a single i.p. injection of azoxymethane followed by 1-week oral exposure of 1% dextran sodium sulfate in drinking water. They are then maintained on a basal diet mixed with UDCA (0.016%, 0.08%, or 0.4%) or sulfasalazine (0.05%) for 17 weeks. At week 20, the tumor-inhibitory effects of both chemicals were assessed by counting the incidence and multiplicity of colonic neoplasms. The immunohistochemical expression of the proliferating cell nuclear antigen labeling index in colonic epithelial malignancies was also assessed. Finally, at week 5, the mRNA expressions for cyclooxygenase-2, inducible nitric oxide synthase, peroxisome proliferator-activated receptor-gamma, and tumor necrosis factor-alpha were measured in nontumorous mucosa.

RESULTS

Feeding the mice with UDCA at all doses significantly inhibited the multiplicity of colonic adenocarcinoma. The treatment also significantly lowered the proliferating cell nuclear antigen labeling index in the colonic malignancies. UDCA feeding reduced the expression of inducible nitric oxide synthase and tumor necrosis factor-alpha mRNA in the colonic mucosa, while not significantly affecting the expression of cyclooxygenase-2 mRNA and peroxisome proliferator-activated receptor-gamma mRNA. Sulfasalazine caused a nonsignificant reduction in the incidence and multiplicity of colonic neoplasia and did not affect these mRNA expression.

CONCLUSIONS

Our findings suggest that UDCA rather than sulfasalazine could serve as an effective suppressing agent in colitis-related colon cancer development in mice.

The role of TNFalpha in ulcerative colitis

Standard of care for ulcerative colitis involves long-term pharmacotherapy or colectomy. Approximately 20% to 30% of patients eventually require a colectomy because patients either do not respond or cannot tolerate the currently available pharmacotherapies. Advances in our knowledge of the pathophysiology of ulcerative colitis have highlighted the importance of cytokines such as tumor necrosis factor alpha (TNFalpha) in the inflammatory process. TNFalpha is a proinflammatory mediator that plays an integral role in the pathogenesis of inflammatory bowel disease. In addition, mounting evidence indicates a genetic association between TNFalpha and ulcerative colitis. Furthermore, increased TNFalpha levels have been demonstrated in studies of patients with ulcerative colitis. TNFalpha is likely an important component in the pathophysiology of ulcerative colitis, and thus agents targeting TNFalpha in ulcerative colitis have been studied. Recent randomized controlled trials have confirmed that biologic anti-TNFalpha therapy is effective in ulcerative colitis. Soluble TNFalpha receptors or biologic agents that suppress or inhibit TNFalpha production may also show therapeutic promise.

Impaired growth plate chondrogenesis in children with chronic illnesses

In mammals, statural growth is primarily accomplished by endochondral ossification, which takes place at the growth plate. Growth plate chondrocyte proliferation, hypertrophy/differentiation, apoptosis, and cartilage matrix synthesis all contribute to chondrogenesis or cartilage formation, a process tightly coupled to the simultaneous remodeling of the cartilage into bone at the metaphyseal border of the growth plate. Growth plate chondrogenesis is regulated by the complex interaction of molecular signals acting systemically as well locally within the growth plate. This network is often dysregulated during chronic illnesses, thus resulting in impaired growth plate chondrogenesis and, in turn, growth failure. The principal events responsible for altered growth plate chondrogenesis in chronic illness are inflammation, protein/calorie deprivation, uremia/metabolic acidosis, glucocorticoids, and impaired GH/IGF-I axis.

Role of tumor necrosis factor receptors in an animal model of acute colitis

TNF-alpha is known to play an important role in inflammatory bowel disease (IBD); however, the pathophysiological role of its receptors is still under study. Acute colitis was induced in rats by intracolonic administration of trinitrobenzene sulfonic acid (TNBS). Control rats received the ethanol vehicle. Rats were sacrificed 72 h later and samples of tissue and fluids were collected. There was a significant increase in the protein levels of sTNF-alpha, sTNFRI, and sTNFRII in the peritoneal fluid (PF) of experimental rats. TNF-alpha, TNFRI, and TNFRII mRNA expression was increased significantly in the colon of experimental animals compared to controls. TRAF3 and TRAF5 expression was also significantly higher, as was that of the adhesion molecules ICAM-1 and E-selectin. The increased expression of TNF-alpha, TNFRs, and the associated signaling factors in the colon of this rat model of IBD provides further evidence for their involvement in the promotion of inflammation and tissue damage. In addition, increased levels of sTNFRs in the PF of experimental rats--particularly sTNFRII--may be involved in the development of colitis by serving as a reservoir of TNF-alpha, and thus provide a novel therapeutic target for IBD.

Immunohistochemical assessment of mucosal cytokine profile in acetic acid experimental colitis

Experimental colitis induced by acetic acid has been used extensively as a model for intestinal inflammatory disease. Colonic tissue lesions of intestinal inflammatory disease patients seem to be related to the increased local production of pro-inflammatory cytokines (IL-1, IL-6, TNF-alpha, and IFN-gamma).

PURPOSE

To assess the cytokine expression pattern identified through immunohistochemistry in colonic mucosa after experimental colitis induced by acetic acid and establish the relationship between this pattern and the presence of macroscopic lesions.

MATERIALS AND METHODS

Adult male Wistar rats (n = 39) were divided at random into 4 groups: NC45 and NC24 (control without colitis; sacrificed at 45 minutes and 24 hours, respectively); and WC45 and WC24 (with experimental colitis induced by acetic acid; sacrificed at 45 minutes and 24 hours, respectively). Macroscopic and microscopic alterations in colonic tissue were evaluated, and cytokine expression was assessed through immunohistochemistry.

RESULTS

After 24 hours, IL-1 expression was greater in the groups with colitis when compared to the groups without colitis. IL-4 expression was higher in the WC45 group. There was an increase in both INF-gamma and IL-6 related to the presence of necrosis of the colonic mucosa in the groups with colitis for both periods evaluated.

CONCLUSION

The immunohistochemical technique was efficient for the analysis of various cytokine expressions in the colonic tissue. There was an increase in the IL-1 pro-inflammatory cytokines as well as in IL-6 and IFN-gamma associated with the presence of colonic necrosis. Experimental colitis induced by acetic acid is a useful model for the development of studies assessing the role of cytokines in the inflammation of mucosa as well as anti-cytokine therapies.

Modulation of nitric oxide and cytokines production by l-arginine in human gut mucosa

BACKGROUND

Arginine is a conditionally essential amino-acid with immuno-modulatory properties, mainly through the nitric oxide (NO) pathway.

AIM

To assess the effects of arginine on intestinal production of pro- and anti-inflammatory cytokines and NO in human gut.

METHODS

An enteral solution of arginine or a control solution of amino-acids was administered to 8 healthy volunteers on a randomized cross-over design. Duodenal biopsies were taken. Pro- (IL-6, IL-8) and anti-inflammatory (IL-4, IL-10) cytokines mRNA expression was assessed by RT-PCR. Other biopsies were cultured with 0.1, 0.5 or 2 mM arginine or control amino-acids, under basal or IL-1beta-induced inflammatory conditions. Interleukin-4, IL-6, IL-8 and IL-10 production was measured in culture supernatant by ELISA and NO production by Griess reaction.

RESULTS

Arginine enhanced the production of NO under inflammatory conditions in a dose-dependent manner (P=0.03). IL-1beta increased the production of IL-8 and IL-6 (P<0.01). Arginine had no effect on pro- and anti-inflammatory cytokines production both under basal and inflammatory conditions.

CONCLUSIONS

Arginine enhanced the production of NO but did not affect that of cytokines in inflammatory human gut. Further clinical studies are required to assess whether arginine-enhanced NO production plays a beneficial or deleterious effect in intestinal inflammation.

[Colonic expression of gamma-interferon and interleukin-10 in Crohn's disease and ulcerative colitis]

OBJECTIVE

The aim of this study was to investigate mucosal expression of INF-gamma and IL-10 in patients with Crohn's disease (CD) or ulcerative colitis (UC).

METHODS

Fourteen patients with CD and 11 patients with ulcerative colitis participated and 7 healthy subjects were also included. Study of the mucosal expression of INF-gamma and IL-10 was conducted using biopsies from healthy and damaged colons, using the inverse transcription and genetic amplification (RT-PCR) technique in real time (Taqman). Our results were expressed as ratio between messenger cytokine (mRNA) levels and ribosomal RNA level of a reference molecule (rRNA 18S), then multiplied by 108.

RESULTS

In the cases of Crohn's disease, the mucosa expressed increased INF-gamma and IL-10 compared with controls (respective medians: 23.03 vs. 1.87 p=0.04 and 20.61 vs. 2.13 p=0.08). A strong positive correlation was found in the mucosal expression of IL-10 and INF-gamma during CD (r=0.9 p<0.0001). In contrast, in patients with UC, the expression of INF-gamma and IL-10 were comparable to those observed in the controls (7.18 vs. 2.18 p=0.36 and 3.66 vs. 1.87 p=0.44).

CONCLUSION

During Crohn's disease, the expression of both IL-10 and INF-gamma was increased and strongly correlated, compared with the controls.

Inflammatory bowel disease: dysfunction of GALT and gut bacterial flora (I)

Gut-associated lymphoid tissue (GALT) is the largest lymphoid organ in the body. This is not surprising considering the huge load of antigens (Ags) from food and commensal bacteria with which it interacts on a daily basis. Gut-associated lymphoid tissue has to recognise and allow the transfer of beneficial Ags whilst concurrently dealing with and successfully removing putative and overtly harmful Ags. This distinctive biological feature of GALT is believed to be crucial to good health. Deregulation or dysfunction of GALT is thought to predispose to inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease. The exact mechanism(s) underlying the pathogenesis of IBD is (are) poorly understood and the immunological defects in GALT are poorly documented. Advances in immunology have highlighted the importance of dendritic cells (DCs), which are the key Ag presenting cells in tissues and lymphoid compartments. Their crucial role in GALT, in health and disease is discussed in this review. Interaction of DCs with T cells in the gut produces a subset of T lymphocytes, which have immunosuppressive function. Inappropriate Ag uptake and presentation to naïve T cells in mesenteric lymph nodes may lead to T cell tolerance in GALT. These various complex factors in the gut are discussed and their possible relevance to IBD evaluated.

Interleukin-1beta and TNF-alpha act in synergy to inhibit longitudinal growth in fetal rat metatarsal bones

We hypothesized that pro-inflammatory cytokines can act locally in the growth plate to impair longitudinal growth. In a model of cultured fetal rat metatarsal bones, we found that IL-1beta and TNF-alpha act in synergy to inhibit longitudinal growth, an effect linked to decreased proliferation and increased apoptosis of growth plate chondrocytes. IGF-I could partially reverse all these effects.

INTRODUCTION

Children with chronic inflammatory conditions, such as Crohn's disease or rheumatoid arthritis, experience impaired longitudinal growth. The inflammatory process itself, which includes upregulation of the pro-inflammatory cytokines interleukin (IL)-1beta, IL-6, and TNF-alpha, is believed to be at least partly responsible for the poor growth in these patients. This study aimed to clarify whether these cytokines can act locally in the growth plate to suppress longitudinal growth and whether any negative effects can be reversed by insulin-like growth factor-I (IGF-I).

MATERIALS AND METHODS

The effects of cytokines on longitudinal bone growth were studied in fetal (day E20) rat metatarsal bones kept in culture. After a 7-day culture, the bones were sectioned, and chondrocyte proliferation was assessed by bromodeoxyuridine (BrdU) incorporation and apoptosis by TUNEL.

RESULTS

When added separately, IL-1beta and TNF-alpha impaired longitudinal bone growth only at a high concentration (100 ng/ml each; p < 0.05 versus control). In contrast, when added in combination, IL-1beta and TNF-alpha potently inhibited growth at far lower concentrations (from 3 ng/ml each; p < 0.001 versus control) and also decreased chondrocyte proliferation and increased apoptosis. Growth failure induced by the combination of IL-1beta and TNF-alpha (10 ng/ml each) could be counteracted by anti-IL-1beta (100 ng/ml; p < 0.001), anti-TNF-alpha (100 ng/ml; p < 0.001), or IGF-I (100 ng/ml; p < 0.01). IL-6 did not affect longitudinal growth even when added in combination with IL-1beta or TNF-alpha (10 ng/ml each).

CONCLUSIONS

We show that IL-1beta and TNF-alpha act in synergy to locally suppress longitudinal growth, an effect that can be partially reversed by IGF-I. Although growth hormone (GH)/IGF-I may improve longitudinal growth in children with chronic inflammatory diseases, our results suggest that the inflammatory process itself must be targeted to achieve normal growth.

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Enhanced intestinal inflammation induced by dextran sulfate sodium in tumor necrosis factor-alpha deficient mice

BACKGROUND AND AIMS

Tumor necrosis factor-alpha (TNF-alpha) is a potent pro-inflammatory cytokine thought to be involved in the pathogenesis of inflammatory bowel disease. To further define the role of TNF-alpha in intestinal inflammation, we studied the effects of dextran sulfate sodium (DSS) administration in mice with targeted deletions of TNF-alpha gene.

METHODS

Acute colitis was induced in female TNF-alpha-/- and TNF-alpha+/+ mice by administering 4.5% DSS orally in drinking water for seven days. The colonic mucosal injury and inflammation was evaluated based on body weight changes, total colon length, luminal hemoglobin, and histological findings. Colonic mRNA expression for inducible nitric oxide synthase (iNOS), TNF-alpha, interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) were measured by reverse transcription polymerase chain reaction (RT-PCR), and nuclear factor kappaB (NF-kappaB) activation was evaluated by electrophoretic mobility shift assay.

RESULTS

In each assessment, colonic injury was significantly aggravated in DSS-treated TNF-alpha-/- mice compared with DSS-treated TNF-alpha+/+ mice. The survival rate of TNF-alpha-/- mice on day seven was 40%; in contrast, all TNF-alpha+/+ mice were alive. Histological study also showed an enhanced infiltration of inflammatory cells, especially neutrophils, and mucosal cell disruption in DSS-treated TNF-alpha-/- mice compared with DSS-treated TNF-alpha+/+ mice. On day seven, mRNA levels of IFN-gamma and IL-4 in the colons of TNF-alpha-/- mice were faint or not detected; in contrast, those of TNF-alpha+/+ mice were detected. Although the expression of iNOS mRNA and luminal nitrite levels were similarly increased in both mice on day seven, this induction was delayed in TNF-alpha-/- mice during the early phase. The degree of NF-kappaB binding activity seemed to be similar between the two types of mice on day seven.

CONCLUSION

DSS-induced inflammation is significantly enhanced in TNF-alpha-/- mice compared to TNF-alpha+/+ mice. These data suggest that persistent and marked blockage of TNF-alpha bioactivity may provide a detrimental effect on acute intestinal inflammation.

Expression of NF-kB in rats with TNBS-induced ulcerative colitis

AIM: To investigate the role of NF-kB in the pathogenesis of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats.

METHODS: Ulcerative colitis model in rat was induced by TNBS. The expression of NF-kB, TNF-α and ICAM-1 protein in colon tissues were detected by immunohistochemistry. The myeloperoxidase (MPO) activity in colon mucosa was detected by biochemistry. The pathological changes in the colon were examined, the relationships among the activity of NF-κB, TNF-α, ICAM-1, and MPO were evaluated.

RESULTS: The activity of NF-kB and the expression of TNF-α, ICAM-1 in rats with TNBS-induced colitis was higher than that in normal control (P < 0.01), a very significant correlation between the expression of NF-kB: 52.14±9.81±30.26±10.20, 60.73±13.41, 45.24±10.86 vs 13.31±4.76, 16.95±6.83, 11.61±4.85, 14.10±5.76; with TNF-α, 74.50±11.20, 48.11±5.95, 84.09±14.52, 53.40±8.79 vs 16.99±5.48, 20.04±6.76, 10.13±1.79, 16.03±6.21; ICAM-1: 68.15±7.25, 44.34±7.54, 77.69±8.09, 47.01±8.82 vs 15.34±4.03, 17.50±6.95, 10.33±2.38, 13.41±4.91, MPO: 1.69±0.11, 0.71±0.06 vs 0.39±0.07, 0.31±0.08; ICAM-1, MPO activity, macroscopic and histological changes in TNBS-induced colitis was found, respectively (r = 0.9304, 0.8680, 0.6865, 0.9 292, 0.8 462; P < 0.001 or P < 0.005).

CONCLUSION: NF-κB may play an important role in the pathogenesis of ulcerative colitis in rats.

Antisense oligonucleotide blockade of tumor necrosis factor-alpha in two murine models of colitis

Tumor necrosis factor-alpha (TNF-alpha) is a key cytokine involved in the pathogenesis of inflammatory bowel disease. We have developed a second-generation antisense oligonucleotide (ISIS 25302) specific for murine TNF-alpha and have evaluated this oligonucleotide in two models of gut inflammation of distinct etiology. ISIS 25302 decreased TNF-alpha mRNA in a dose- and sequence-dependent manner in vitro in the mouse macrophage cell line P388D1. It also reduced TNF-alpha mRNA in vivo, in whole adipose tissue and in macrophages isolated from the adipose tissue of db/db mice, a strain with constitutively high expression of TNF-alpha. ISIS 25302 significantly reduced disease activity index scores in mice with both an acute and a chronic form of dextran sodium sulfate (DSS)-induced colitis. It also significantly improved histopathological scores in interleukin (IL)-10-deficient mice. This was accompanied by reductions in both the basal and lipopolysaccharide-stimulated secretion of TNF-alpha and interferon-gamma in colonic organ cultures from IL-10 -/- mice. In this model, efficacy was obtained with both a prophylactic treatment regimen or a therapeutic dosing protocol begun after colitis was already present. In both the DSS and IL-10 -/- models, scrambled and mismatch control oligonucleotides were largely without effect, suggesting that ISIS 25302 was exerting its effects through a sequence-dependent antisense mechanism.

Antigen-presenting dendritic cells in ulcerative colitis

BACKGROUND

Antigen-presenting dendritic cells are the inducers and regulators of immune responses. Here, we have discussed the phenotype and function of dendritic cells in situ and their alteration during lymphocytapheresis in patients with ulcerative colitis.

METHODS

Dendritic cells were enriched from the peripheral blood mononuclear cells by culturing with granulocyte-macrophage colony-stimulating factors and interleukin 4 for 8 days. The function of dendritic cells was evaluated in an allogenic mixed leukocyte reaction. Flow cytometry was employed to study the phenotype of dendritic cells. Lymphocytapheresis was done by a continuous flow centrifugation technique using a CS-3000 separator. Immunohistochemical methodology was employed to detect dendritic cells at the colonic mucosa.

RESULTS

Peripheral blood dendritic cells had increased functional capacity, and these cells were matured and activated compared to dendritic cells from normal controls. CD83-positive activated and mature dendritic cells were found at the colonic mucosa from patients with ulcerative colitis. Lymphocytapheresis induced decreased function of peripheral blood dendritic cells in patients with ulcerative colitis. Also, the levels of inflammatory cytokines were reduced by lymphocytapheresis.

CONCLUSIONS

Increased function of dendritic cells may be related to the inflammatory mucosal milieu found in patients with ulcerative colitis. Depletion of dendritic cells during lymphocytapheresis may downregulate the exacerbated immune response in patients with ulcerative colitis.

Macrophage migration inhibitory factor activates antigen-presenting dendritic cells and induces inflammatory cytokines in ulcerative colitis

The level of macrophage migration inhibitory factor (MIF) and the functions of dendritic cells (DC) are up-regulated in the peripheral blood, and the numbers of MIF-expressing cells and mature DC are increased at the colonic mucosa from patients with ulcerative colitis (UC). However, a functional relationship between MIF and DC, and the role of MIF in the pathogenesis of UC, are not clear. In this study, we showed that a pure population of peripheral blood DC is a new and still unknown source of MIF. DC from UC patients produced significantly higher levels of MIF (17 x 5 +/- 9 x 8 ng/ml, n = 10) compared with patients with Crohns disease (CD) (4 x 6 +/- 2 x 5 ng/ml, n = 5, P< 0 x 01) and control subjects (5 x 0 +/- 2 x 6 ng/ml, n = 10, P< 0 x 01). A double immunofluorescence study revealed the expression of MIF by CD83-positive mature DC at the colonic mucosa from UC patients. Blood DC treated with high amounts of MIF (500 ng/ml) showed a significantly higher stimulatory capacity (43287 +/- 5998 CPM, n = 5) in an allogenic mixed leucocyte reaction compared with untreated DC (27528 +/- 8823 CPM, n = 5, P< 0 x 05). Study of intracellular cytokine expression showed that MIF induced significant levels of interleukin (IL)-1 and IL-8 in monocytes and DC from UC and CD patients. These results showing the capacity of MIF to induce increased functional capacity of DC, and to produce IL-1 and IL-8 from monocytes and DC, indicate a role of MIF in the induction and/or perpetuation of the inflammatory environment in UC.

Glutamine decreases interleukin-8 and interleukin-6 but not nitric oxide and prostaglandins e(2) production by human gut in-vitro

BACKGROUND

Glutamine modulates cytokine production in various tissues but its effects on the production of other inflammatory mediators such as eicosanoids and nitric oxide have not been investigated in human gut.

AIM

To evaluate the influence of glutamine on interleukin (IL)-8, IL-6, nitric oxide and prostaglandin E(2) production by human gut.

METHODS

Ten fasted volunteers received either enteral glutamine or isonitrogenous amino acids over 6 h in a cross-over design. Series of duodenal biopsies were frozen or cultured for 24 h with 0.5 or 5 mM of glutamine or amino acids. IL-6, IL-8 and PGE(2) were measured in culture media by ELISA and nitrites by Griess assay. mRNA levels for IL-6, IL-8, Cyclooxygenase-2 and NO synthase-2 were assessed in biopsies by RT-PCR. Results in percent, (median [range]) were compared by Wilcoxon test.

RESULTS

Glutamine decreased IL-8 and IL-6 in-vitro production: 63 [2-173] vs 100 [19-177] and 37 [5-489] vs 100 [33-431], both P<0.05. IL-8 mRNA level also decreased in biopsies cultured with 5 mM glutamine: 26 [13-142] vs 92 [34-215], P<0.05. Nitrites and PGE(2) concentrations were not significantly affected by glutamine.

CONCLUSION

Glutamine has a specific inhibitory effect on pro-inflammatory cytokine production in the gut and may contribution to the modulation of intestinal inflammation.

Deficiency of interstitial cells of Cajal in the small intestine of patients with Crohn's disease

OBJECTIVE

Interstitial cells of Cajal are critical for the generation of electrical slow waves that regulate the phasic contractile activity of the tunica muscularis of the GI tract. Under certain pathophysiological conditions loss of interstitial cells of Cajal may play a role in the generation of certain motility disorders. The aim of the present study was to determine if there is an abnormality in the density or distribution of interstitial cells of Cajal from patients with Crohn's disease.

METHODS

Small intestines from control subjects and patients with Crohn's disease were examined using immunohistochemistry and antibodies against the Kit receptor, which is expressed in interstitial cells of Cajal within the tunica muscularis of the GI tract. The density and distribution of interstitial cells of Cajal were assessed in the longitudinal and circular muscle layers and in the myenteric and deep muscular plexus regions of Crohn's and control tissues.

RESULTS

Tissues from Crohn's disease patients showed an almost complete abolition of interstitial cells of Cajal within the longitudinal and circular muscle layers and a significant reduction in numbers at the level of the myenteric and deep muscular plexuses.

CONCLUSIONS

In tissues from Crohn's disease patients, the density of interstitial cells of Cajal was reduced throughout the tunica muscularis in comparison to control small intestines. The disturbance of intestinal motility that occurs in patients with Crohn's disease may be a consequence of the loss of or defects in specific populations of interstitial cells of Cajal within the tunica muscularis.

Efficacy of treatment with chimeric monoclonal antibody (Infliximab) to tumor necrosis factor-alpha for Crohn's disease in Japan: evaluation by rapid turnover proteins, and radiologic and endoscopic findings

BACKGROUND

Several studies have reported that the chimeric monoclonal antibody to tumor necrosis factor (TNF)-alpha (Infliximab) is extremely valuable in the treatment of Crohn's disease. The aim of this study was to clarify the efficacy of this treatment in Japanese patients with Crohn's disease.

METHODS

A 12-week multicenter, open trial of Infliximab was carried out and involved 25 patients with moderate to severe Crohn's disease who were resistant to conventional treatment. Patients received a single 2-h intravenous infusion of Infliximab at a dose of 1, 3, 5 or 10 mg/kg bodyweight. Clinical evaluation of this treatment response was defined as a reduction in the index of the inflammatory bowel disease (IOIBD) and of the Crohn's disease activity index scores (CDAI), and in serum levels of C-reactive protein (CRP) at 2, 4, 8 and 12 weeks, and as an increase in serum levels of rapid turnover proteins as well as improvement of radiologic and endoscopic findings at 4 weeks.

RESULTS

The IOIBD score was reduced after 4 weeks in 66.7% of the group receiving 1 mg/kg Infliximab, 71.4% in the group receiving 3 mg/kg, 80.0% in the group receiving 5 mg/kg, and 85.7% in the group receiving 10 mg/kg. Improvement was better maintained over 12 weeks in the 5 and 10 mg/kg groups compared with the 1 and 3 mg/kg groups. Similar results were obtained for the CDAI scores. Serum levels of rapid turnover proteins significantly increased to within the normal ranges after infusion in all groups. Seven of the 11 (63.6%) patients evaluated showed improvement of radiologic and endoscopic findings.

CONCLUSIONS

A single infusion of Infliximab was effective for the treatment of Japanese patients with Crohn's disease. Serum rapid turnover proteins reflected the clinical response to antibody for TNF-alpha well.

Characterization of antigen-presenting dendritic cells in the peripheral blood and colonic mucosa of patients with ulcerative colitis

OBJECTIVE

Increased lymphocyte activation and production of inflammatory cytokines are implicated in the pathogenesis of ulcerative colitis. Because antigen-presenting dendritic cells play a cardinal role in the activation and survival of activated lymphocytes, the aim of the present study was to characterize dendritic cells in ulcerative colitis.

DESIGN

This study was designed to compare the phenotypes and functions of peripheral blood dendritic cells among healthy normal volunteers and patients with ulcerative colitis or Crohn's disease. Activated dendritic cells were also localized at the colonic mucosa.

METHODS

Peripheral blood dendritic cells were generated from 15 patients with ulcerative colitis, 10 patients with Crohn's disease and 15 healthy control volunteers. The stimulatory capacities of dendritic cells were analysed in an allogenic mixed lymphocyte reaction. Nitric oxide was detected by the Griess method. Single- and dual-colour flow cytometry was employed to study the levels of maturation of dendritic cells. Activated dendritic cells were localized immunohistochemically in the colonic mucosa.

RESULTS

In comparison to normal controls, peripheral blood dendritic cells from patients with ulcerative colitis showed significantly increased stimulatory capacities (P < 0.05) and produced significantly higher levels of nitric oxide (P < 0.05). The numbers of activated dendritic cells were also significantly higher in ulcerative colitis (P < 0.05). Mature and activated dendritic cells expressing the CD83 antigen were detected at the inflamed colonic mucosa in patients with ulcerative colitis and Crohn's disease.

CONCLUSIONS

Activated and mature dendritic cells may have a role in the induction of an exacerbated immune response in ulcerative colitis. This study provides the scientific and logical basis for blocking the maturation and activation of dendritic cells in ulcerative colitis as a new therapeutic intervention.

Influence of glutamine on cytokine production by human gut in vitro

BACKGROUND

glutamine modulates cytokine production by immune cells in vitro and protects the gut from experimental enterocolitis, but data on the effect of glutamine on cytokine production in human gut are lacking.

AIM

to assess the effect of glutamine pre-treatment in vivo and in vitro on cytokine production by intestinal mucosa.

METHODS

nine fasted volunteers received either enteral glutamine or saline over 6 h in a cross-over design. Duodenal biopsies were cultured for 24 h with or without glutamine. Cytokine content of culture media was analysed by ELISA, and the expression of cytokine mRNA in biopsies was assessed by semi-quantitative RT-PCR.

RESULTS

glutamine given in vivo and in vitro significantly decreased IL-6 [1.4 (0.8-8.5) vs 8.9 (1.0-43.9)] and IL-8 production [5.8 (0-51.4) vs. 53.0 (2.5-114.6), pg/mg wet tissue], median (range), both P< or =0.01, in comparison to no glutamine experiments. Glutamine did not influence IL-4 production. IL-1beta, IL-10 and TNF-alpha were not detectable in culture media. The expression of any cytokine mRNA was not influenced by glutamine.

CONCLUSIONS

glutamine reduces pro-inflammatory cytokine production by human intestinal mucosa, probably by a post-transcriptional pathway. Glutamine could be useful to modulate inflammatory conditions with imbalanced cytokine production.

Fas/Fas ligand expression and characteristics of primed CD45RO+ T cells in the inflamed mucosa of ulcerative colitis

BACKGROUND

Chronic immune activation in the colon is characteristic of ulcerative colitis (UC). Fas/Fas ligand (FasL) system is a mechanism responsible for activation-induced cell death (AICD), which maintains homeostasis within the immune system. Thus, Fas/FasL expression on activated colonic T cells of UC patients, as well as the susceptibility of such T cells to AICD was investigated in order to determine the role of activated colonic T cells in the long lasting inflammation in UC.

METHODS

Fas, FasL, and CD45RO expression on peripheral blood and colonic T cells of UC patients were assayed by flow cytometry. Apoptosis of colonic T cells induced by anti Fas antibody was assessed using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay.

RESULTS

The majority of colonic T cells expressed both CD45RO and Fas in the colonic mucosa, a situation that was quite different from that in the peripheral blood. The number of CD45RO+CD8+ and Fas+CD8+ T cells was significantly lower in UC patients than the controls, unlike the number of Fas+CD4+ T cells. In contrast, the number of both CD45RO+CD4+ and CD45RO+CD8+ T cells in UC mucosa expressing FasL was significantly higher than in the controls. While Fas mediated apoptosis of CD45RO+CD8+ T cells was higher in UC patients than the controls, the number of apoptotic CD45RO+CD4+ T cells from UC mucosa was not.

CONCLUSIONS

In UC patients, CD45RO+CD4+ T cells are less sensitive to apoptotic signals mediated by Fas. These phenomena may contribute to the pathogenesis of UC.

Differential impact of nicotine on cellular proliferation and cytokine production by LPS-stimulated murine splenocytes

The immunoregulatory effects of nicotine have not been fully clarified and the reported data are often conflicting. The present study investigated the role of nicotine as an immunomodulator of murine splenocytes stimulated by lipopolysaccharide (LPS), the endotoxin component of gram-negative bacteria. BALB/c female mice of two different ages, young (2-3 months) and old (18-22 months), were used. The cells were incubated with nicotine at two different time points, 3 h pre-incubation and concurrent incubation relevant to LPS stimulation, before further incubation for 48 or 72 h. Treatment of murine splenocytes with nicotine showed an impact on cellular proliferation as well as on the production of the pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). The results indicated that nicotine significantly inhibited cellular proliferation of murine splenocytes in a concentration-related manner (32, 64 and 128 microg/ml). Timing of nicotine exposure prior to LPS stimulation was critical in terms of immunological impact on cytokine production. TNF-alpha and IL-6 production were significantly enhanced by 1 microg/ml of nicotine when cells were pre-incubated with nicotine for 3 h compared to concurrent incubation relative to LPS stimulation. The alteration in cytokine production varied with the age of the mouse. TNF-alpha production was significantly inhibited by nicotine in young mice, while IL-6 production was significantly inhibited by nicotine in old mice. Since any immunomodulation that alters the profile of these cytokines may cause an imbalance in the immune system impinging on health status, these findings may be important when dealing with the concept of nicotine as a therapeutic agent.

Gut-associated lymphoid tissues in ulcerative colitis

BACKGROUND

The main feature of ulcerative colitis (UC) is numerous infiltration of not only lymphocytes and plasma cells but also neutrophils and macrophages, indicating acute on chronic inflammation. Recent studies show that apoptosis may play an important role in the regulation of gut-associated lymphoid tissues (GALT). Therefore, this study was performed to clarify apoptosis of lymphocytes in the peripheral blood and colonic mucosa of UC.

METHODS

Three-color flow cytometry was used to clarify apoptosis of lymphocytes in the peripheral blood and colonic mucosa of patients with active and inactive UC compared with controls using fluorescence-labeled monoclonal and polyclonal antibodies such as Fas (CD95), Fas ligand, CD4, CD8, CD45RO, etc.

RESULTS

The ratio of Fas and CD45RO double-positive cells in the peripheral blood of UC patients was significantly increased in CD8 but not CD4 T cells when compared with controls. The ratio of Fas-positive and CD45RO-negative cells was significantly increased in CD4 and CD8 T cells of UC when compared with controls. There was unbalanced immunoregulation between CD4 and CD8 T cells in the colonic mucosa of UC probably due to apoptosis through Fas-Fas ligand system.

CONCLUSIONS

Abnormal GALT system was found in UC probably due to dysregulation of T cells through Fas-Fas ligand system.