Intestinal antigen uptake is enhanced in inflammatory bowel disease. We analyzed transcellular transport routes of antigens in different compartments of normal enterocytes and atypical intestinal epithelial cells called "rapid antigen uptake into the cytosol enterocytes" (RACE cells). These cells constitute a recently described population of enterocyte-derived cells, which are increased in inflammatory bowel disease. Mucosa of freshly resected specimens were incubated with the antigens ovalbumin or horseradish peroxidase. Ultrastructural labeling patterns of differentiation-dependent proteins, the brush-border enzyme sucrase-isomaltase and the cytoskeleton proteins villin and actin, were determined in enterocytes. Apoptosis was investigated biochemically and ultrastructurally by cleavage of caspase-3. Both antigens were transported to late endosomes and to trans-Golgi vesicles of enterocytes in inflammatory bowel disease and control specimens. Quantitative evaluation revealed a significantly increased transepithelial antigen transport in both compartments of RACE relative to normal enterocytes. Labeling densities for sucrase-isomaltase, villin, and actin were decreased in RACE relative to normal enterocytes. Caspase-3 was not increased in RACE cells relative to controls. RACE cells are characterized by increased antigen transport to late endosomes and the trans-Golgi network, a disassembled cytoskeleton and lower concentrations of proteins that are markers of cell differentiation.

Background: Recruitment of circulating cells to the inflamed intestine is modulated by adhesion molecules expressed on the surface of both leucocytes and endothelial cells. Aims: The objective of this study was to test whether 2`-O-methoxyethyl chimeric antisense oligonucleotides directed against endothelial intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) can downregulate leucocyte-endothelial interactions and thereby attenuate inflammation in rat experimental ileitis. Methods: Indomethacin (7.5 mg/kg ) was injected subcutaneously into Sprague-Dawley rats 48 and 24 hours prior to intravital microscopy. Animals were treated with either ICAM-1 (ISIS 17470), VCAM-1 (ISIS 18155), or scrambled control antisense oligonucleotides administered subcutaneously or intravenously in parallel with indomethacin. Leucocyte trafficking was observed in ileal submucosal collecting venules. Macroscopic and histological grades of inflammation were measured 48 hours after the first indomethacin application. ICAM-1 and VCAM-1 expression in ileal submucosal venules was detected by immunohistochemistry. Results: Intravenous administration of ICAM-1 oligonucleotides 2 mg/kg (rolling leucocytes 5.7 (2.4)/0.01 mm2 endothelial surface, adherent leucocytes 0.8 (1.1)) and VCAM-1 oligonucleotides 8 mg/kg (9.2 (4.4), 0.6 (0.8)) significantly reduced leucocyte adhesion compared with diseased controls (27.8 (5.3), 14 (4.4)) in a dose dependent manner whereas subcutaneous treatment did not. Correspondingly, macroscopic and histological inflammation was significantly decreased. ICAM-1 oligonucleotides markedly reduced endothelial ICAM-1 expression while VCAM-1 oligonucleotides clearly diminished endothelial VCAM-1 expression. Conclusions: Both ICAM-1 and VCAM-1 2`-O-methoxyethyl chimeric antisense oligonucleotides attenuate rat ileitis by downregulation of leucocyte adherence and thus are potential candidates for anti-inflammatory treatment in inflammatory bowel disease.

Several reports have implicated reactive oxygen and nitrogen metabolites (RONS) in the initiation and/or progression of inflammatory bowel diseases (IBDs). We have investigated the role of three key RONS-metabolizing enzymes (inducible nitric oxide synthase [iNOS], superoxide dismutase [SOD], nicotinamide adenine dinucleotide phosphate [NADPH] oxidase) in a murine model of IBD. Mice genetically deficient (−/−) in either iNOS or the p47phox subunit of NADPH oxidase, transgenic (Tg) mice that overexpress SOD, and their respective wild-type (WT) littermates were fed dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis. In addition, the specific iNOS inhibitor 1400W was used in DSS-treated WT and p47phox−/− mice. WT mice responded to DSS feeding with progressive weight loss, bloody stools, elevated serum NOX and colonic mucosal injury with neutrophil infiltration. Both the onset and severity of colitis were significantly attenuated in iNOS−/− and 1400W-treated WT mice. While the responses to DSS did not differ between WT and p47phox−/− mice, enhanced protection was noted in 1400W-treated p47phox−/− mice. Interestingly, SODTg mice exhibited more severe colitis than their WT littermates. These findings reveal divergent roles for superoxide and iNOS-derived NO in intestinal inflammation.

Adhesion molecules have been implicated in the pathogenesis of inflammatory bowel diseases. We investigated their expression and contribution to leukocyte recruitment in experimental intestinal inflammation. Ileitis was induced in Sprague-Dawley rats by two injections of indomethacin (7.5 mg/kg), given 24 h apart. Endothelial intercellular adhesion molecule-1 (ICAM-1) expression was quantified using the dual radiolabeled monoclonal antibody technique and Mac-1 (CD11b/CD18) expression on leukocytes by flow cytometry. Leukocyte infiltration was monitored by tissue myeloperoxidase (MPO) activity. The first indomethacin injection induced a time- and site-dependent increase of ICAM-1 expression in ileal mucosa and muscularis. The second injection resulted in a reduction of ICAM-1 expression below constitutive levels whereas Mac-1 was upregulated. MPO changes paralleled lesion development over 48 h. ICAM-1 and MPO values were correlated for the first 24 h. Immunoneutralization of either ICAM-1 or Mac-1 attenuated mucosal injury. We conclude that (i) indomethacin-induced ileitis is associated with a temporally disassociated upregulation of ICAM-1 and (ii) despite a reduction in ICAM-1 after 24 h, ICAM-1, in concert with Mac-1, contributes to mucosal injury and leukocyte infiltration elicited by indomethacin.

Cigarette smoking is beneficial in ulcerative colitis and nicotine is presumably the ingredient responsible for this effect.We therefore evaluated the effect of nicotine on experimental colitis in mice deficient for the a5 neuronal nicotine acetylcholine receptor subunit (nAChR).Nicotine (12.5 ug/ml) was added to the drinking water of a5 deficient mice for 7 days prior to the induction of colitis by adding 2.5% dextran sodium sulphate (DSS) to the drinking water.The control group of a 5 deficient mice received only DSS.Disease activity index was determined by scoring changes in body weight and the presence of gross bleeding in the stool.Animals were sacrificed 7 days after DSS treatment.The colon was resected, weighed, mucosal MPO activity and PGE 2 generation were determined.The severity of DSS induced colitis in the a5 deficient mice was significantly decreased following pretreatment with nicotine.The disease activity score was reduced by 63% and body weight decreased by only 30% as compared to the control mice that were not pretreated with nicotine.Mucosal MPO activity and PGE 2 generation were also significantly lower in nicotine pretreated mice.Conclusions: I.The amelioration of DSS induced colitis in the a 5 deficient mice by nicotine suggests that this neuronal nicotinic acetylcholine receptor subunit have an important role in the pathogenesis of experimental colitis.2.These results also suggest that this receptor subunit may be involved in the pathogenesis of IBD and indicate the possible mechanism whereby cigarette smoking affect ulcerative colitis.

Many patients infected with the helminth Schistosoma mansoni suffer from gastrointestinal symptoms, including nausea and dysentery as well as hepatosplenomegaly.Epidemiological research has shown that there is a significant difference in the level of infection with this parasite between children and adults.This age-related difference is possibly due to a shift in susceptibility to infection.To investigate these age-related changes in S.

Table1macro scopi c findings afte r laparotomy according to the score de scrib ed by Yamad a.Using intr avital micro scop y roll ing and sticking leuk ocyt es (leukos) were anal ysed in submucosa l collec ting venules of the ileum.Results : As shown in table I, AKBA treated rats demonstrated a sig nificant reduction of rolling and sticking leuk ocyte s as well as a significant redu ction in the extend of inflamm atory lesions .Only In rats treated with AKBA showed a positive fecal occ ult blood test.Conclusions: These results sugg est that 5-lip oxygenase products of the endogenous arachidonic cascade may be involved in the pathogenesis of the chronic ileiti s induced by Indo .They also demonstrate that inhibiti on of leukotrienne biosynthesis may be a promissing concept in the clinical treatment of patients with IBD.6158

AGAA577saline.Rats were sacrificed 3 days after IA, the colon isolated, lesion area measured and mucosal MPO activity was determined.ISS significantly decreased the severity of DSS induced colitis.In ISS treated mice the disease activity score and % change in body weight were 17% and 8% of the respective levels in mice treated with DSS only.MPO activity was also significantly reduced in ISS treated mice.ISS also significantly decreased the severity of IA induced colitis in rats: The lesion area in IA+ISS was 62±35 mm2 as compared to 570±74 mm2 in rats treated with IA only.MPO activity in IA treated rats -6.0±1.8 u1g was six folds higher than in IA +ISS -1.1 ±O.l u1g (P<0.05).Conclusion: Systemic administration of ISS effectively ameliorates experimental colitis.This form of active immunotherapy may be of value for the maintenance of remission in IBD.