Severe Chronic Colitis Research Articles

Divergent Adaptations in Autonomic Nerve Activity and Neuroimmune Signaling Associated With the Severity of Inflammation in Chronic Colitis.

The autonomic nervous system (ANS) is thought to play a critical role in the anti-inflammatory reflex pathway in acute colitis via its interaction with the spleen and colon. Inflammation in the intestine is associated with a blunting of vagal signaling and increased sympathetic activity. As a corollary, methods to restore sympatho-vagal balance are being investigated as therapeutic strategies for the treatment of intestinal inflammation. Nevertheless, it is indefinite whether these autonomic signaling adaptations in colitis are detrimental or beneficial to controlling intestinal inflammation. In this study, models of moderate and severe chronic colitis are utilized to resolve the correlations between sympatho-vagal signaling and the severity of intestinal inflammation. Spleens and colons were collected from Winnie (moderate colitis), Winnie-Prolapse (severe colitis), and control C57BL/6 mice. Changes to the size and histomorphology of spleens were evaluated. Flow cytometry was used to determine the expression of adrenergic and cholinergic signaling proteins in splenic B and T lymphocytes. The inflammatory profile of the spleen and colon was determined using a RT-PCR gene array. Blood pressure, heart rate, splanchnic sympathetic nerve and vagus nerve activity were recorded. Spleens and colons from Winnie and Winnie-Prolapse mice exhibited gross abnormalities by histopathology. Genes associated with a pro-inflammatory response were upregulated in the colons from Winnie and further augmented in colons from Winnie-Prolapse mice. Conversely, many pro-inflammatory markers were downregulated in the spleens from Winnie-Prolapse mice. Heightened activity of the splanchnic nerve was observed in Winnie but not Winnie-Prolapse mice. Conversely, vagal nerve activity was greater in Winnie-Prolapse mice compared with Winnie mice. Splenic lymphocytes expressing α1 and β2 adrenoreceptors were reduced, but those expressing α7 nAChR and producing acetylcholine were increased in Winnie and Winnie-Prolapse mice. Sympathetic activity may correlate with an adaptive mechanism to reduce the severity of chronic colitis. The Winnie and Winnie-Prolapse mouse models of moderate and severe chronic colitis are well suited to examine the pathophysiology of progressive chronic intestinal inflammation.

Effects of jianguiqre decotion combined with mesalazine enteriic-coated tablets and bifid triple capsule dissolving at testines on the efficacy, TCM scores and inflammatory factors of patients with severe chronic colitis.

Effects of jianguiqre decotion combined with mesalazine enteriic-coated tablets and bifid triple capsule dissolving at testines on the efficacy, TCM scores and inflammatory factors of patients with severe chronic colitis

Deficiency of neutrophil extracellular traps increases susceptibility to colonic inflammation

Abstract Neutrophil extracellular traps (NETs), DNA structures released from neutrophils, are primarily enriched with bactericidal proteins. We envision that the antimicrobial nature of NETs would be an appropriate immune response in the gut, which is continuously exposed to trillions of bacteria. NETs formation is peptidyl arginine deiminase-4 (PAD4)-dependent, therefore, we employed Pad4KO mice and their WT littermates in two well-established models of murine colitis, i.e., loss of IL-10 signaling (immune hyperactivation) and chemical-induced injury (DSS). Upon treatment with αIL-10R mAb, Pad4KO mice developed robust chronic colitis as exemplified by colomegaly, colonic crypt elongation, and increased immune cell infiltration. In comparison, αIL-10R-treated WT mice exhibited modest colitis. We theorized that NETs may function as a ‘safety net’ which confine the pro-inflammatory neutrophil granule proteins (NGP) and prevent them to cause further damage. Indeed, the concentration and activity of NGP [i.e. lipocalin 2 (Lcn2), myeloperoxidase (MPO) and neutrophil elastase (NE)], in serum and in colons, were strikingly elevated in colitic Pad4KO mice, when compared to WT mice. The level of colonic secretory leukocyte protease inhibitor (SLPI) was reduced in the colitic Pad4KO mice. Such impaired SLPI response coupled with the ‘spillover’ of NGPs may, in part, explain the aggravated colitis in mice lacking NETs. Similarly, upon DSS treatment Pad4KO mice developed more severe chronic colitis than WT mice. Taken together, our findings advance the notion that gastrointestinal NETs are beneficial, and elucidation of NETs-mediated signaling, during colitis, may yield a novel therapeutic approach to mitigate intestinal inflammation.

P080 NEUTROPHIL EXTRACELLULAR TRAPS DEFICIENCY AGGRAVATES CHRONIC COLITIS

Neutrophils can release their DNA as neutrophil extracellular traps (NETs) via a programmed cell death known as NETosis; this process is dependent on peptidyl arginine deiminase-4 (PAD4, aka Padi4) activity to facilitate the rapid de-condensation of chromatin into NETs. We envision that the formation of NETs would be an appropriate immune response in the gut, which is continuously exposed to trillions of bacteria. To test this hypothesis, we employed the NETs-deficient Pad4KO mice and their WT littermates in two well-established models of murine colitis, i.e., loss of IL-10 signaling (immune hyperactivation) and chemical-induced injury (DSS). Upon treatment with αIL-10R mAb, Pad4KO mice developed robust chronic colitis, as exemplified by splenomegaly, colomegaly, increased levels of serum and fecal lipocalin 2 (Lcn2). Histological analysis revealed colonic crypt elongation, heightened immune cell infiltrates, and loss of goblet cells in the colitic Pad4KO mice. In comparison, αIL-10R-treated WT littermates exhibited modest colitis. We theorized that NETs may function as a ‘safety net’ which confine the pro-inflammatory neutrophil granule proteins (NGP) and prevent them to cause further damage. Indeed, the concentration and activity of NGP [i.e., Lcn2, myeloperoxidase (MPO) and neutrophil elastase (NE)], in serum and in colons, were strikingly elevated in colitic Pad4KO mice, when compared to WT mice. Intriguingly, the level of colonic secretory leukocyte protease inhibitor (SLPI) was reduced in the colitic Pad4KO mice. Such impaired SLPI response coupled with the ‘spillover’ of neutrophil granule proteins may, in part, explain the aggravated colitogenesis in mice lacking NETs. Similarly, upon DSS treatment the Pad4KO mice developed more severe chronic colitis than WT mice. Taken together, our findings advance the notion that gastrointestinal NETs are beneficial and caution that the use of PAD4 or NETs inhibitors may not be favorable for intestinal diseases.

Toll-like receptor-4 differentially mediates intestinal and extra-intestinal immune responses upon multi-drug resistant Pseudomonas aeruginosa association of IL10\u2212/\u2212 mice with chronic colitis

BackgroundInfections with multi-drug resistant (MDR) Gram-negative bacteria including Pseudomonas aeruginosa (PA) have become a serious threat particularly in hospitalized patients with immunopathological co-morbidities. The well-balanced interplay between immune cells, pattern recognition receptors such as Toll-like receptor (TLR)-4 sensing lipopolysaccharide from Gram-negative bacteria including PA, and evolving pathways is crucial to prevent the host from invading (opportunistic) pathogens. Information regarding the molecular mechanisms underlying the interactions between intestinal carriage of MDR PA and host immunity during chronic large intestinal inflammation is scarce, however.Methods and resultsWe therefore perorally challenged conventionally colonized TLR4-deficient IL10−/− mice and IL10−/− counterparts displaying comparably severe chronic colitis with a clinical MDR PA strain. PA could more sufficiently establish in the intestinal tract of TLR4-deficient IL10−/− mice until day 14 postinfection (p.i.), whereas within 48 h the majority of IL10−/− mice had already expelled the opportunistic pathogen from their guts. Intestinal colonization properties of PA in TLR4-deficient IL10−/− mice were associated with distinct genotype-dependent differences in gut microbiota compositions before challenge given that TLR4-deficient IL10−/− mice harbored more fecal enterobacteria and enterococci, but lower Clostridium/Eubacterium burdens. At day 14 p.i., PA-induced increases in colonic immune cells such as macrophages, monocytes and T-lymphocytes could be observed in TLR4-deficient IL10−/− mice, but not IL10−/− counterparts, that were accompanied by a more distinct secretion of IFN-γ in the colon and TNF in the mesenteric lymph nodes (MLN) of the former as compared to the latter. Conversely, splenic TNF levels were lower in TLR4-deficient IL10−/− mice as compared to IL10−/− controls at day 14 p.i. Interestingly, more pronounced apoptotic responses could be assessed in colonic epithelia of PA-challenged IL10−/− mice only. This was paralleled by enhanced pro-inflammatory cytokine secretion not only in the intestines, but also in extra-intestinal compartments of IL10−/− mice as indicated by increased concentrations of nitric oxide in the colon, IFN-γ in the MLN and IL-12p70 in the spleen at day 14 p.i.ConclusionsUnder chronic intestinal inflammatory conditions including IL10−/− colitis MDR PA-association results in well-orchestrated TLR4-dependent immune responses both in intestinal and extra-intestinal compartments. Further studies should unravel the underlying molecular mechanisms in more detail.

PTH-051 Influence of Iron Supplementation on The Natural History of Colitis

Introduction Iron deficiency anaemia is common in IBD. Iron supplementation may induce or exacerbate colitis in rats (APT 2001;15:1989–99).Dysbiosis of the microbiota is common in IBD and iron contributes to this as it is a growth factor for pathogenic bacteria.We investigated the effect of dietary iron supplementation and/or reduction on the severity of chronic colitis in a murine model using clinical, histological and biochemical parameters. Methods Studies were performed on 6 groups of 8 wild type (WT) C57BL/6 mice.Chronic colitis was induced with 1.25% Dextran Sodium Sulphate (DSS) for 5 days,followed by16 further days on water [for 3 consecutive cycles]. DSS-treated mice were fed one of three diets:low iron [LI] (100 ppm), normal iron [NI] (200 ppm) and high iron[HI] (400 ppm) supplemented chow. Also, 3 non-DSS-treated groups were studied and fed similarly. Half of the mice in each control group were treated with 1 cycle of acute 2% DSS for 5 days at day 53, followed by 5 further days on water. All mice were sacrificed at day 63. Daily weights and clinical features were recorded. Histological colitis was scored using the Bauer score(Gut 2010; 59:1192–99).Faecal calprotectin was measured by ELISA and faecal iron by immunoassay at various time points [day (d) 1, 21, 42 & 63]. Statistical analyses used the Kruskal–Wallis test with post-hoc analysis. Results Oral DSS administration induced colitis in all treated mice. While chronic DSS colitis was not associated with weight loss, there was severe weight loss in acute DSS mice which was greatest in the low iron diet group (p = 0.001 LI vs. HI; p = 0.01 for LI vs. NI). Histologically, the colitis features were more prominent in acute DSS-treated mice ingesting low and high iron diets, with median colitis scores 6 & 5.5 respectively.Cyclic administration of DSS in drinking water resulted in a significant rise in faecal calprotectin, from baseline to d63 in LI (p = 0.05) and for HI (p = 0.01), but this was not significant in the NI group. In acute DSS, the rise was greater in LI and HI (p = 0.001) and less in NI (p = 0.01).Total faecal iron was increased in a dose-dependent manner within 9 weeks in all non-DSS groups. Nevertheless, in chronic DSS groups, p = 0.001 at d1 vs. d63 for all groups [382% change for LI, 331% for NI and 355% for HI].However, in acute DSS p = 0.05 for LI, p = 0.001 NI & HI (d1 vs. d10). Conclusion Changes in nutritional luminal iron exacerbate colitis.Oral administration of DSS causes a reproducible acute colitis, followed by a slow recovery phase with a concomitant chronic inflammation. Chronic colitis was worse in mice fed low or high iron diets, as shown by elevated calprotectin. Faecal iron rose equally in all 3 groups: with iron increases likely arising from diet and bleeding during colitis. Dysbiosis may be a consequence of this change in luminal iron. Disclosure of Interest None Declared

Effect of acute and chronic DSS induced colitis on plasma eicosanoid and oxylipin levels in the rat

Eicosanoids and oxylipins are potent lipid mediators involved in the regulation of inflammation. In order to evaluate their role and suitability as biomarkers in colitis, we analyzed their systemic levels in the acute and chronic phase of dextran sulfate sodium (DSS) induced colitis. Male Fischer 344 rats were treated in three cycles with 4% DSS in the drinking water (4 days followed by 10 days recovery) and blood was drawn 3 days prior to the first DSS treatment and on days 4, 11, 32 and 39. Histopathological evaluation of the colon tissue after 42 days showed that the animals developed a mild to severe chronic colitis. Consistently, prostaglandin levels were massively (twofold) elevated in the colonic tissue. LC–MS based targeted metabolomics was used to determine plasma oxylipin levels at the different time points. In the acute phase of inflammation directly after DSS treatment, epoxy-fatty acid (FA), dihydroxy-FA and hydroxy-FA plasma concentrations were uniformly elevated. With each treatment cycle the increase in these oxylipin levels was more pronounced. Our data suggest that in the acute phase of colitis release of polyunsaturated FAs from membranes in the inflamed tissue is reflected by a uniform increase of oylipins formed in different branches of the arachidonic acid cascade. However, during the recovery phases the systemic oxylipin pattern is not or only moderately altered and does not allow to evaluate the onset of chronic inflammation in the colon.

Impaired self-renewal and increased colitis and dysplastic lesions in colonic mucosa of AKR1B8-deficient mice.

Ulcerative colitis and colitis-associated colorectal cancer (CAC) is a serious health issue, but etiopathological factors remain unclear. Aldo-keto reductase 1B10 (AKR1B10) is specifically expressed in the colonic epithelium, but downregulated in colorectal cancer. This study was aimed to investigate the etiopathogenic role of AKR1B10 in ulcerative colitis and CAC. Ulcerative colitis and CAC biopsies (paraffin-embedded sections) and frozen tissues were collected to examine AKR1B10 expression. Aldo-keto reductase 1B8 (the ortholog of human AKR1B10) knockout (AKR1B8(-/-)) mice were produced to estimate its role in the susceptibility and severity of chronic colitis and associated dysplastic lesions, induced by dextran sulfate sodium (DSS) at a low dose (2%). Genome-wide exome sequencing was used to profile DNA damage in DSS-induced colitis and tumors. AKR1B10 expression was markedly diminished in over 90% of ulcerative colitis and CAC tissues. AKR1B8 deficiency led to reduced lipid synthesis from butyrate and diminished proliferation of colonic epithelial cells. The DSS-treated AKR1B8(-/-) mice demonstrated impaired injury repair of colonic epithelium and more severe bleeding, inflammation, and ulceration. These AKR1B8(-/-) mice had more severe oxidative stress and DNA damage, and dysplasias were more frequent and at a higher grade in the AKR1B8(-/-) mice than in wild-type mice. Palpable masses were seen in the AKR1B8(-/-) mice only, not in wild-type. AKR1B8 is a critical protein in the proliferation and injury repair of the colonic epithelium and in the pathogenesis of ulcerative colitis and CAC, being a new etiopathogenic factor of these diseases.

The chronic exposure to low doses of endosulfan increases the expression of proinflammatory molecules, and induces leukemia and lymphoma in mice.

Event Abstract Back to Event The chronic exposure to low doses of endosulfan increases the expression of proinflammatory molecules, and induces leukemia and lymphoma in mice. Galina P. Zaitseva1*, Martha C. Tellez-Bañuelos1, Jorge Peregrina1 and Jesse Haramati1 1 Universidad de Guadalajara, Departamento de Biologia Celular Molecular, CUCBA, Mexico INTRODUCTION. Endosulfan, a pesticide widely used in Mexico, has been shown to have lymphoproliferative effects and may also facilitate the development of cancer. OBJECTIVE. To assess the effect of chronic exposure to low doses of endosulfan on the expression of adhesion molecules in the colon, levels of cytokines in serum, and histopathological changes in the tissues of spleen, colon and liver. MATERIALS AND METHODS. Commercially-sourced Endosulfan was diluted in olive oil and administered (2mg/kg) to mice of both sexes via oral ad gavage for 24 weeks. In the control group only olive oil was administered. Over a 52 weeks period, two mice (male and female) per week from both experimental groups were euthanized with 0.1ml subcutaneous pentobarbital. Serum levels of the cytokines IL-6, IL-10 and TNF-alpha were determined using a commercial ELISA kit (Abcam). The colons were fixed in 10% formalin and processed for histology; the resulting sections were stained using a conventional hematoxylin-eosin protocol. The immunohistochemical staining was performed using monoclonal antibodies directed to P-selectin and ß-catenin and developed with an avidin-biotin kit. RESULTS. The LD50 of Endosulfan was determined to be 8mg/kg for females and 11.5 mg/kg for males. The sublethal dose used in this study caused acute inflammation of the colon from week 3 and significantly increased serum IL-6 and P-selectin expression in the colon from week 5 of pesticide administration in females and from week 7 of administration in males. After 12 weeks of endosulfan exposure the inflammation of the colon progressed to severe chronic colitis with precancerous elements; after 24 weeks high levels of TNF-a were observed. Serum IL-10 was found to be increased by 7 and 24 weeks of exposure. At 24 weeks of exposure, ß-catenin was found to be strikingly expressed in aberrant crypts. At 30 weeks we observed positive staining in spleen and liver for the leukemia markers CD34 CD3 and PAX-5. At 52 weeks we observed the evolution of this leukemia to solid tumors pathologically graded as lymphoma. CONCLUSIONS. Chronic exposure to endosulfan, even at very low doses, induces over-expression of molecules that indicate that an expanded inflammatory process in the colon causes severe chronic colitis. Additionally, administration of Endosulfan induces rapid development of aberrant crypts as precancerous elements in the murine colon and later term lympho-proliferative tumors. These effects were observed in both sexes, but were more rapid and more pronounced in females. Keywords: Cytokines, Endosulfan, pesticide, P-Selectin, Inflammation, Cancer, Leukemia, Lymphoma, mouse model Conference: IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología, Medellin, Colombia, 13 Oct - 16 Oct, 2015. Presentation Type: Poster Presentation Topic: Tumor immunology Citation: Zaitseva GP, Tellez-Bañuelos MC, Peregrina J and Haramati J (2015). The chronic exposure to low doses of endosulfan increases the expression of proinflammatory molecules, and induces leukemia and lymphoma in mice.. Front. Immunol. Conference Abstract: IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología. doi: 10.3389/conf.fimmu.2015.05.00064 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 May 2015; Published Online: 14 Sep 2015. * Correspondence: PhD. Galina P Zaitseva, Universidad de Guadalajara, Departamento de Biologia Celular Molecular, CUCBA, Guadalajara, Mexico, galina.mex@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Galina P Zaitseva Martha C Tellez-Bañuelos Jorge Peregrina Jesse Haramati Google Galina P Zaitseva Martha C Tellez-Bañuelos Jorge Peregrina Jesse Haramati Google Scholar Galina P Zaitseva Martha C Tellez-Bañuelos Jorge Peregrina Jesse Haramati PubMed Galina P Zaitseva Martha C Tellez-Bañuelos Jorge Peregrina Jesse Haramati Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Deficient production of reactive oxygen species leads to severe chronic DSS-induced colitis in Ncf1/p47phox-mutant mice.

BackgroundColitis is a common clinical complication in chronic granulomatous disease (CGD), a primary immunodeficiency caused by impaired oxidative burst. Existing experimental data from NADPH-oxidase knockout mice propose contradictory roles for the involvement of reactive oxygen species in colitis chronicity and severity. Since genetically controlled mice with a point-mutation in the Ncf1 gene are susceptible to chronic inflammation and autoimmunity, we tested whether they presented increased predisposition to develop chronic colitis.MethodsColitis was induced in Ncf1-mutant and wild-type mice by a 1st 7-days cycle of dextran sulfate sodium (DSS), intercalated by a 7-days resting period followed by a 2nd 7-days DSS-cycle. Cytokines were quantified locally in the colon inflammatory infiltrates and in the serum. Leukocyte infiltration and morphological alterations of the colon mucosa were assessed by immunohistochemistry.ResultsClinical scores demonstrated a more severe colitis in Ncf1-mutant mice than controls, with no recovery during the resting period and a severe chronic colitis after the 2nd cycle, confirmed by histopathology and presence of infiltrating neutrophils, macrophages, plasmocytes and lymphocytes in the colon. Severe colitis was mediated by increased local expression of cytokines (IL-6, IL-10, TNF-α, IFN-γ and IL-17A) and phosphorylation of Leucine-rich repeat kinase 2 (LRRK2). Serological cytokine titers of those inflammatory cytokines were more elevated in Ncf1-mutant than control mice, and were accompanied by systemic changes in functional subsets of monocytes, CD4+T and B cells.ConclusionThis suggests that an ineffective oxidative burst leads to severe chronic colitis through local accumulation of peroxynitrites, pro-inflammatory cytokines and lymphocytes and systemic immune deregulation similar to CGD.

Successful Treatment with Infliximab for Inflammatory Colitis in a Patient with X-linked Anhidrotic Ectodermal Dysplasia with Immunodeficiency

X-linked anhidrotic ectodermal dysplasia with immunodeficiency (X-EDA-ID) is caused by hypomorphic mutations in the gene encoding nuclear factor-κB essential modulator protein (NEMO). Patients are susceptibile to diverse pathogens due to insufficient cytokine and frequently show severe chronic colitis. An 11-year-old boy with X-EDA-ID was hospitalized with autoimmune symptoms and severe chronic colitis which had been refractory to immunosuppressive drugs. Since tumor necrosis factor (TNF) α is responsible for the pathogenesis of NEMO colitis according to intestinal NEMO and additional TNFR1 knockout mice studies, and high levels of TNFα-producing mononuclear cells were detected in the patient due to the unexpected gene reversion mosaicism of NEMO, an anti-TNFα monoclonal antibody was administered to ameliorate his abdominal symptoms. Repeated administrations improved his colonoscopic findings as well as his dry skin along with a reduction of TNFα-expressing T cells. These findings suggest TNF blockade therapy is of value for refractory NEMO colitis with gene reversion.

Enterococcus faecalis Strains Differentially Regulate Alix/AIP1 Protein Expression and ERK 1/2 Activation in Intestinal Epithelial Cells in the Context of Chronic Experimental Colitis

Monoassociation of germfree Interleukin 10 gene deficient (IL-10-/-) 129SvEv but not wild-type mice with Enterococcus faecalis induces severe chronic colitis. Bacterial strain-specific effects on the development of chronic intestinal inflammation are not understood. We investigated the molecular mechanisms of E. faecalis OG1RF (human clinical isolate, colitogenic) and E. faecalis ms2 (endogenous isolate from an IL-10-/- mouse) in initiating chronic experimental colitis using IL-10-/- mice. Monoassociation of IL-10-/- mice for 14 weeks revealed significant differences in colonic inflammation (3.6 +/- 0.2 and 2.4 +/- 0.6 for OG1RF and ms2, respectively) (n = 5 mice in each group) (histological scoring (0-4)). Consistent with the tissue pathology, gene expression of the pro-inflammatory chemokine interferon-gamma inducible protein-10 (IP-10) was significantly higher in intestinal epithelial cells (IEC) derived from E. faecalis OG1RF monoassociated IL-10-/- mice. We further compared the differentially E. faecalis induced colitis on the epithelial level by 2D-SDS PAGE coupled with MALDI-TOF MS. Proteome analysis identified 13 proteins which were differentially regulated during disease progression in the epithelium of E. faecalis-monoassociated IL-10-/- mice. Regulation of Alix/AIP1 protein expression and ERK1/2 phosphorylation was validated in primary IEC and epithelial cell lines, suggesting a protective role for Alix/AIP1 in the process of disease progression. Alix/AIP1 protein expression was further characterized in epithelial cell lines using siRNA-mediated knock-down. Our study demonstrates E. faecalis strain-specific induction of colitis in IL-10-/- mice after 14 weeks of monoassociation. Our study suggests that Alix/AIP1 protein expression and ERK1/2 activation are decreased in severe colitis.

Treatment of experimental colitis in mice with LMP-420, an inhibitor of TNF transcription

BackgroundLMP-420 is a boronic acid-containing purine nucleoside analogue that transcriptionally inhibits TNF production but is non-cytotoxic to TNF-producing cells.MethodsThis study investigated the efficacy of LMP-420 as an anti-inflammatory agent in acute and chronic colitis induced by oral administration of dextran sulfate sodium (DSS) to mice and in chronic colitis following piroxicam administration to IL-10-deficient mice. The severity of colon inflammation was assessed histologically. TNF levels were measured by enzyme immunoassay.ResultsAdministration of DSS for 7 days resulted in severe acute colitis that was associated with a marked increase in stool and colon tissue TNF levels. Initiation of therapy with intraperitoneal (i.p.) LMP-420 on day 4 of DSS exposure decreased colonic TNF to near normal levels on day 7. However, neither i.p. nor oral treatment with LMP-420 affected the development or severity of acute DSS colitis. Initiation of LMP-420 therapy after 3 cycles of DSS administration to establish chronic colitis also had no effect on the severity of chronic colitis. Analysis of colonic TNF combined with longitudinal analysis of TNF and TNF receptor (TNF-RII) levels in stool during the development of chronic DSS colitis demonstrated that the initially elevated colonic TNF levels returned to normal despite intense on-going inflammation in mice with chronic colitis. RAG-2-/- mice deficient in T and B cells also developed severe ongoing colitis in response to 3 cycles of DSS, but showed marked differences vs. wild type mice in stool TNF and TNF-RII in response to DSS exposure. Systemic and oral LMP-420 treatment for 16 days decreased colonic TNF levels in IL-10-deficient mice with chronic colitis, with a trend to decreased histologic inflammation for oral LMP-420.ConclusionThese studies demonstrate that short-term treatment with a transcriptional inhibitor of TNF production can decrease systemic and local colonic levels of TNF but may not decrease the histologic severity of colitis. Longer term studies using colitis models that are more dependent on TNF elevation should be performed to more accurately assess the potential of LMP-420 for therapy of inflammatory bowel disease.

Mouse strain differences in inflammatory responses of colonic mucosa induced by dextran sulfate sodium cause differential susceptibility to PhIP‐induced large bowel carcinogenesis

In mice, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induces a high incidence of malignant lymphoma and leukemia, but exhibits little, if any, carcinogenic activity in the large intestine after long-term exposure. However, recent studies have revealed that colonic adenocarcinomas can be efficiently and rapidly induced by combined treatment with PhIP and dextran sulfate sodium (DSS), a potent inducer of colitis. In the present study, the authors investigated the effects of inflammation on PhIP-induced carcinogenesis using two mouse strains, C57BL/6J and MSM/Ms, showing distinct temporal profiles of inflammatory responses to DSS. A long-term carcinogenesis experiment conducted with a single i.g. administration of PhIP (200 mg/kg body weight), followed by DSS treatment in drinking water for 4-6 days, revealed an increase in tumor incidence in C57BL/6J mice in accordance with the DSS intake. In contrast, neoplastic lesions were rarely observed in the MSM/Ms strain. From the short-term exposure to DSS for 4 days, C57BL/6J mice demonstrated severe chronic colitis, accompanied by hyperplastic cryptal epithelium and extensive cellular infiltration. Splenomegaly and swelling of mesenteric lymph nodes were also evident for over 1 month as chronic symptoms of systemic immunological disturbance. However, no inflammatory lesions were detected in MSM/Ms mice. The present results provide strong evidence that prolonged chronic inflammatory responses induced by DSS are directly responsible for the observed enhancement of PhIP-induced large bowel carcinogenicity.

Therapeutic effect of a new immunosuppressive agent, everolimus, on interleukin-10 gene-deficient mice with colitis

A limited number of therapeutic strategies are currently available for patients with inflammatory bowel disease (IBD). In particular, the maintenance therapy after remission in Crohn's disease (CD) is not satisfactory and new approaches are needed. Interleukin-10 gene-deficient (IL-10-/-) mice, a well-characterized experimental model of CD, develop severe chronic colitis due to an aberrant Th1 immune response. Everolimus, an inhibitor of the mammalian target of rapamycin (mTOR), a new immunosuppressive reagent, has been used successfully in animal models for heart, liver, lung and kidney transplantation. In the present study, we examined the efficacy of everolimus in the treatment of chronic colitis in an IL-10-/- mouse model. Everolimus was administered orally for a period of 4 weeks to IL-10-/- mice with clinical signs of colitis. The gross and histological appearances of the colon and the numbers, phenotype and cytokine production of lymphocytes were compared with these characteristics in a control group. The 4-week administration of everolimus resulted in a significant decrease in the severity of colitis, together with a significant reduction in the number of CD4+ T cells in the colonic lamina propria as well as IFN-gamma production in colonic lymphocytes. Everolimus treatment of established colitis in IL-10-/- mice ameliorated the colitis, probably as a result of decreasing the number of CD4+ T cells in the colonic mucosa and an associated reduction in IFN-gamma production.

Therapeutic effects of roxithromycin in interleukin-10-deficient colitis

A limited number of therapeutic strategies are currently available to treat patients with inflammatory bowel disease (IBD). Interleukin-10 (IL-10)-deficient mice, well characterized as an experimental model of IBD, develop severe chronic colitis because of aberrant Th1 responses. Roxithromycin (RXM), a macrolide antibiotic, has received attention because it offers not only antibacterial but also immunosuppressive effects. We examined the immunosuppressive effect of RXM on the development of IBD. To test the efficacy of short-term administration of RXM, elder IL-10-deficient mice (16-20 weeks old) with established colitis were orally treated for 10 days with RXM (20 mg/kg per day). To test the long-term preventive effects of RXM, for 20 weeks young adult IL-10-deficient mice (4-5 weeks old) also were administered RXM orally (20 mg/kg per day). The short-term treatment-oriented administration of RXM reduced the degree of inflammatory change and lowered serum amyloid A in IL-10-deficient mice with severe colitis. Mononuclear cells from the lamina propria of RXM-treated large intestines showed lower production of IFN-gamma than did those from diseased mice that were untreated. Long-term prevention-oriented administration of RXM suppressed the development of severe colitis and decreased production of IFN-gamma and IL-12. In addition to its expected immunosuppressive effect, RXM treatment also decreased the level of Bacteroides vulgatus, a Gram-negative anaerobe. The anti-inflammatory changes observed in IL-10-deficient mice resulted from the efficacy of RXM as an immunosuppressant as well as from its efficacy as an antibiotic. According to our findings, RXM would seem to have significant potential as a preventive and/or therapeutic agent for IBD.

Dietary fatty acids modulate chronic colitis, colitis-associated colon neoplasia and COX-2 expression in IL-10 knockout mice

Objective The effects of different dietary oils on the development of colitis-associated colon cancer have not been studied. The present study examined the effect of different dietary oils on the severity of chronic colitis, development of colitis-associated premalignant changes, and colonic expression of cyclooxygenase-2 (COX-2) in interleukin-10 knockout (IL-10 −/−) mice. Methods IL-10 −/− mice were fed chow supplemented with corn oil (CO; control, n = 28), olive oil (OO; n = 29), or fish oil (FO; n = 35) for 12 wk and their colons were studied for colitis score, premalignant changes, and COX-2 expression. Results The average colitis score was higher in the FO than in the CO group. Similarly, the incidence of severe colitis (score ≥ 3) was significantly higher in the FO than in the CO and OO groups (50% versus 7.7% and 3.7%, respectively, P < 0.05). Dysplasia was more frequent in the FO and less frequent in the OO than in the CO group (47% and 4% versus 15%, respectively, P < 0.05). Conversely, aberrant crypt foci and crypt index were significantly higher in the FO than in the CO group. Colitis score, aberrant crypt foci, and crypt index did not differ between the OO and CO groups. COX-2 immunostaining was significantly lower in the OO than in CO group ( P < 0.05) but not different between the FO and CO groups. Conclusions In IL-10 −/− mice, fish oil exacerbates chronic colitis and colitis-associated premalignant changes. Conversely, olive oil inhibits COX-2 immunostaining and decreases the risk of neoplasia associated with chronic colitis.

The Use of Recombinant Human Keratinocyte Growth Factor (Palifermin) to Ameliorate Treatment-Induced Mucositis

Eicosanoids and oxylipins are potent lipid mediators involved in the regulation of inflammation. In order to evaluate their role and suitability as biomarkers in colitis, we analyzed their systemic levels in the acute and chronic phase of dextran sulfate sodium (DSS) induced colitis. Male Fischer 344 rats were treated in three cycles with 4% DSS in the drinking water (4 days followed by 10 days recovery) and blood was drawn 3 days prior to the first DSS treatment and on days 4, 11, 32 and 39. Histopathological evaluation of the colon tissue after 42 days showed that the animals developed a mild to severe chronic colitis. Consistently, prostaglandin levels were massively (twofold) elevated in the colonic tissue. LC–MS based targeted metabolomics was used to determine plasma oxylipin levels at the different time points. In the acute phase of inflammation directly after DSS treatment, epoxy-fatty acid (FA), dihydroxy-FA and hydroxy-FA plasma concentrations were uniformly elevated. With each treatment cycle the increase in these oxylipin levels was more pronounced. Our data suggest that in the acute phase of colitis release of polyunsaturated FAs from membranes in the inflamed tissue is reflected by a uniform increase of oylipins formed in different branches of the arachidonic acid cascade. However, during the recovery phases the systemic oxylipin pattern is not or only moderately altered and does not allow to evaluate the onset of chronic inflammation in the colon.