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PubMedDate not supplied

Chronic diarrhoea in non collagenous microscopic colitis: therapeutic effect of cholestyramine.

Chronic watery diarrhoea is the main symptom of the microscopic colitis syndrome, including collagenous colitis (CC), lymphocytic colitis (LC), and not otherwise specified (NOS) colitis. The goal of this study was to evaluate the anti-diarrhoeal effect of cholestyramine in non collagenous microscopic colitis. The records of 13 patients with LC and 7 patients with NOS, who had received cholestyramine as first line therapy and who responded to a questionnaire, were reviewed. On an intention to treat basis, a good clinical effect of cholestyramine was achieved in 75 % of the patients in both LC and NOS colitis. There was no therapeutic effect in 15 % of the patients, who all had LC. In general, the anti-diarrhoeal effect appeared within one week of treatment. Cholestyramine provides a rapid and adequate symptomatic relief of the diarrhoea in non collagenous microscopic colitis.

Adult↗
PubMed1984

CT findings in ulcerative, granulomatous, and indeterminate colitis.

Eight patients with ulcerative colitis, three with colitis indeterminate, and 15 patients with Crohn disease were studied by computed tomography (CT) to establish CT criteria for each disorder in hopes of providing a new diagnostic perspective useful in the radiographic evaluation of inflammatory colitis. The CT findings in ulcerative colitis included thickening of the colon wall (mean, 7.8 mm), which was characterized by inhomogeneous attenuation and a "target" appearance of the rectum, and proliferation of perirectal fat. Bowel wall thickening (mean, 13 mm) with homogeneous attenuation, fistula and abscess formation, and mesenteric abnormalities were observed in patients with Crohn colitis. Patients with colitis indeterminate showed colonic changes on CT observed in both disorders. Initial experience suggests that CT can differentiate patients with well established ulcerative and Crohn colitis.

Abscess↗
PubMedDate not supplied

[Should subdivision of regressive ischemic colitis be envisaged?].

The term "regressive ischemic colitis" is generally accepted and refers to acute hemorrhagic colitis which may occur at any age and recovers spontaneously in most cases, sometimes leaving colonic stenosis due to scarring. Critical analysis of the literature reveals that there is no formal diagnostic criterion for this condition and no real proof that the mechanism is ischemic, particularly in young subjects who have no vascular disorder or hemodynamic triggering factor. The number of clinical, radiological, endoscopic and even histological similarities between regressive ischemic colitis and some forms of infectious colitis, particularly due to enterohemorrhagic E. coli O157:H7 and hemorrhagic colitis due to penicillin derivatives and non-steroid anti-inflammatory drugs is also striking. These observations logically lead us to wonder whether the term "regressive ischemic colitis" does really correspond to a well-defined entity rather than to a group of acute colitis of miscellaneous etiology but with many common features.

Adult↗
PubMed1995

Colorectal cancer in patients with ulcerative colitis. A prospective cohort study in Italy.

BACKGROUND: The aim of this study was to assess the development of dysplasia or cancer in patients with ulcerative colitis and to determine the effectiveness of colonoscopy and biopsy follow-up in colon cancer surveillance. METHODS: From 1980 to 1986, 65 patients who had ulcerative colitis for 7 years or more participated in a surveillance program of colonoscopy and biopsy. This cohort was followed until December 1992. Forty-nine patients (75.4%) had extensive colitis and 16 (24.6%) left-sided colitis. The mean disease duration was 17.2 years. Three hundred four colonoscopies were performed. During each endoscopy, random biopsies were performed. RESULTS: Seven patients had definite dysplasia of the colorectal mucosa. Four of them had high grade lesions and underwent surgery. In all of these patients, colon cancer (3 Dukes' Stage A, 1 Dukes' Stage B) was found. No cancer was found in the other patients. Pedunculated adenomas were excised from 6 other patients during colonoscopy. When dysplasia was diagnosed, these patients were older than those who were dysplasia free, whereas the age at onset of colitis was significantly higher in the former (P < 0.01). Fifteen patients discontinued follow-up. Two of them developed colon cancer diagnosed at an advanced stage. CONCLUSIONS: Dysplasia, especially of high grade, is a marker of colon cancer risk in patients with longstanding ulcerative colitis. Intensive colonoscopy and biopsy surveillance can lead to the diagnosis of colon cancer at a potentially curable stage. In this series, older age appeared to be an additional risk factor. A careful selection of patients with ulcerative colitis seems mandatory to minimize the cost and optimize the benefit of colon cancer surveillance programs.

Adult↗
PubMed2005

Cyclosporine A for induction of remission in severe ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) is characterized by a life-long chronic course with remissions and exacerbations. Approximately 15% of patients have a severe attack requiring hospitalization at some time during their illness. These patients are traditionally treated with intravenous corticosteroids, with a response rate of approximately 60%. The patients who do not respond to steroid treatment usually require surgical removal of the large bowel (proctocolectomy or colectomy with an anal pouch). This surgical procedure essentially cures the patient from the disease but is associated with complications such as pouchitis. Few alternative treatments exist for severe ulcerative colitis: immunosuppressive medications (such as azathioprine) have a slow onset of action and are therefore usually ineffective. Antibiotics are not proven to be effective and biological treatments such as infliximab are still under investigation. The introduction of cyclosporine-A (CsA) for use in patients with severe ulcerative colitis (UC) has provided an alternative to patients previously facing only surgical options. Cyclosporine acts mainly by inhibiting T lymphocyte function, which is essential for the propagation of inflammation. Unlike most other immunosuppressive agents, CsA does not suppress the activity of other hematopoietic cells, does not cause bone marrow suppression and has a rapid onset of action. This reviews aims to systematically assess the effectiveness and safety of CsA for severe UC. OBJECTIVES: This review aimed to evaluate the effectiveness of cyclosporine A for patients with severe ulcerative colitis. SEARCH STRATEGY: Electronic searches of The Cochrane Library (Issue 1, 2004), EMBASE (1980-2004), and MEDLINE (1966-2004); hand searching the references of all identified studies; contacting the first author of each included trial. SELECTION CRITERIA: Randomised clinical trials comparing cyclosporine A with placebo or no intervention to obtain and maintain remission of idiopathic ulcerative colitis. DATA COLLECTION AND ANALYSIS: Two reviewers independently appraised the quality of each trial and extracted the data from the included trials. Relative risks (RR) with 95% confidence intervals (CI) were estimated. The reviewers assumed an intention to treat analysis for the outcome measures. MAIN RESULTS: Only two randomized controlled trials were identified that satisfied the inclusion criteria. These two trials could not be pooled for analysis because of major differences in design and patient populations. In the first trial, 11 patients received intravenous cyclosporine (4 mg/kg) and 9 received placebo. Two of 11 in the treatment group failed to respond to therapy compared with nine of nine in the placebo group (RR 0.18, 95% CI 0.05 - 0.64). However, 3/11 and 4/9 eventually underwent colectomy in the treatment and placebo groups respectively and follow-up was less than a month. In the second trial 15 patients were treated with intravenous cyclosporine and 15 with intravenous methylprednisolone. Five of 15 patients in the cyclosporine group failed to respond to therapy as compared to 7/15 in the methylprednisolone group (RR 0.71, 95% CI 0.29 - 1.75). After 1 year 7/9 responders in the cyclosporine group were still in remission compared with 4/8 in the steroid group (p > 0.05) and the colectomy rate was similar in both groups. The mean time to response in the cyclosporine group in the 2 trials was short (7 days and 5.2 days). These results should be interpreted with caution given the small numbers of trials and patients evaluated for comparison, and limited follow-up (few weeks in one trial to a year in the other). The precise assessment of the occurrence of adverse events was difficult because the trials described different adverse reactions, which reversed after discontinuation of cyclosporine. There was no evidence in the trials reviewed that cyclosporine was more effective than standard treatment for preventing colectomy but this effect cannot be excluded due to the small sample size and rarity of this outcome. Additional limitations of current research include lack of data on quality of life, costs and long-term results of cyclosporine therapy. AUTHORS' CONCLUSIONS: There is limited evidence that cyclosporine is more effective than standard treatment alone for severe ulcerative colitis. The relatively quick response makes the short-term use of cyclosporine potentially attractive, but the long-term benefit is unclear, when adverse events such as cyclosporine-induced nephrotoxicity may become more obvious. There is a need for additional research on quality of life, costs and long-term results from cyclosporine therapy in severe ulcerative colitis.

Colitis, Ulcerative↗
PubMed1995

Evidence that CD4+, but not CD8+ T cells are responsible for murine interleukin-2-deficient colitis.

Mice deficient in interleukin-2 production (IL-2null mice) develop colonic inflammation closely resembling ulcerative colitis in humans. Although this disease is marked by substantial infiltration of the colon by CD8+ and CD4+ T lymphocytes, no function has yet been assigned to these T cell subsets in the development of colitis in the IL-2null mouse. For the present study, we investigated the involvement of T lymphocytes in the onset of colitis in IL-2null mice, and examined the possible role played by cytotoxic T cells. Both lamina propria lymphocytes (LPL) and intraepithelial lymphocytes (IEL) of the colon of IL-2null mice were potently cytotoxic ex vivo in short-term redirected cytotoxic lymphocyte (CTL) assays. In contrast, colonic T cells of wild-type animals showed little or no constitutive cytotoxic T cell activity. Colonic CTL were detectable prior to the appearance of disease in IL-2null animals and CTL activity was confined to the TcR alpha beta, rather than to the TcR gamma delta IEL subset. IL-2null animals crossed with major histocompatibility complex class I-deficient mice [IL-2null x beta 2 microglobulin (beta 2mnull) mice] also developed colitis, which appeared even earlier than in most IL-2null mice. These findings suggest that neither CD8+ IEL nor LPL were causal in the onset of colitis in IL-2null animals. In IL-2null x beta 2mnull mice, an ulcerative colitis-like disease was evident from histological studies and immunohistological staining which showed very large numbers of CD4+ lymphocytes within the intestinal mucosa. Significant ex vivo killing by CD4+ T cells was observed in IL-2null x beta 2null animals, although this required an extended incubation time compared to colonic CD8+ T cells. Peripheral as well as colonic CD4+ T cells in IL-2null and IL-2null x beta 2mnull animals, were activated as judged by their cell surface phenotype (CD45RBlo, L-selectinlo and CD69+). In light of these findings, we propose that infiltrating CD4+, but not CD8+ T cells are central to the inflammation observed in the intestinal mucosa in IL-2null colitis.

Animals↗
PubMed2007

Remission-inducing effect of anti-TNF monoclonal antibody in TNBS colitis: mechanisms beyond neutralization?

BACKGROUND: Tumor necrosis factor (TNF) plays an important role in the pathogenesis of several inflammatory diseases. Its expression is increased in inflamed mucosa of Crohn's disease patients and anti-TNF treatment improves mucosal inflammation. Besides neutralization, induction of apoptosis of monocytes/macrophages and T cells is thought to be an important mechanism of action of the anti-TNF monoclonal antibody therapy. The aim was to investigate the pathogenic role of TNF in hapten-induced colitis models and to study the relationship between apoptosis induction and disease remission. METHODS: In 2 murine colitis models (trinitrobenzene sulphonic acid, TNBS, and oxazolone colitis), mice were injected daily with anti-TNF monoclonal antibody (mAb). Macrophages were collected from lamina propria of TNBS colitis mice. 7AAD and anti-active-caspase-3 staining were used to study DNA degradation and intracellular caspase activation. A pan-caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK), was given to a subgroup of the colitis mice. RESULTS: Treatment with anti-TNF effectively reduced intestinal mucosal inflammation in TNBS colitis but not in oxazolone colitis. Effectiveness was evidenced by a more rapid recovery of body weight and reduced cell infiltration, and downregulation of proinflammatory cytokines interferon-gamma (IFN-gamma), TNF, and IL-18 at the mRNA level. Apoptosis was induced in lamina propria macrophages after treatment with anti-TNF, and it was abrogated through short-term pretreatment with Z-VAD-FMK. CONCLUSION: Anti-TNF downregulates proinflammatory cytokines and decreases cell infiltration in the bowel after TNBS application. The remission-inducing effect of anti-TNF may partly rely on apoptosis induction.

Amino Acid Chloromethyl Ketones↗
PubMed2007

Symptomatic overlap between irritable bowel syndrome and microscopic colitis.

BACKGROUND: Microscopic colitis is diagnosed on the basis of histologic criteria, and irritable bowel syndrome (IBS) is diagnosed by symptom-based criteria. There has been little investigation into the symptomatic overlap between these conditions. Our aim was to assess the prevalence of symptoms of irritable bowel syndrome in a population-based cohort of patients with microscopic colitis. METHODS: The Rochester Epidemiology Project (REP), a medical records linkage system providing all health care data for the defined population of Olmsted County, Minnesota, was used to identify all county residents with a diagnosis of microscopic colitis between 1985 and 2001. The medical records of these individuals were reviewed to ascertain symptoms consistent with Rome, Rome II, and Manning criteria for irritable bowel syndrome. RESULTS: One hundred thirty-one cases of microscopic colitis were identified. Median age at diagnosis was 68 years (range, 24-95); 71% were women. Sixty-nine (53%) and 73 (56%) met Rome and Rome II criteria for irritable bowel syndrome, respectively. Fifty-four (41%) had three or more Manning criteria. Forty-three (33%) had previously been diagnosed with irritable bowel syndrome. CONCLUSIONS: In this population-based cohort of histologically confirmed microscopic colitis, approximately one-half met symptom-based criteria for the diagnosis of irritable bowel syndrome. The clinical symptom-based criteria for irritable bowel syndrome are not specific enough to rule out the diagnosis of microscopic colitis. Therefore, patients with suspected diarrhea-predominant irritable bowel syndrome should undergo biopsies of the colon to investigate for possible microscopic colitis if symptoms are not well controlled by antidiarrheal therapy.

Adult↗
PubMed2000

Short- and long-term follow-up of treatment for lymphocytic and collagenous colitis.

Collagenous colitis and lymphocytic colitis cause chronic watery diarrhea. Multiple therapies have been found to improve symptoms but there have been few long-term follow-up studies. Our goal was to obtain long-term clinical follow-up on a cohort of patients with independently confirmed typical histopathologic changes. Pathology slides from 32 cases of collagenous or lymphocytic colitis patients from 1988-1992 were independently reviewed. Twenty-five cases were confirmed by both groups of pathologist as collagenous or lymphocytic colitis. For these 25 patients, charts were reviewed and telephone follow-up interviews were performed in 1992 and 1995. Seven of 32 (22%) of the original cases were not confirmed on independent pathologic interpretation. A 15.8% discordance rate was found between the different groups of pathologists. Patient demographics were similar to previously published reports except one-half of our patients had diarrhea of only 6 months or less. Eighty-one percent of patients receiving 5-ASA agents reported improvement as well as 100% of those receiving prednisone. At 23 month follow-up 86% of patients reported improvement in diarrhea and only 32% required routine medications. At 47 month follow-up all patients reported improved diarrhea and only 29% required routine medications. Collagenous and lymphocytic colitis can sometimes be identified in patients with relatively brief duration diarrhea. Clinical parameters and response to therapy are similar for collagenous or lymphocytic colitis. Most patients with lymphocytic and collagenous colitis improve with therapy such as 5-ASA preparations or steroids. Over a follow-up period of several years, most patients have improvement in diarrhea and generally do not require maintenance medications. Independent pathologic confirmation of the diagnosis should be obtained in patients not responding to therapy.

Aged↗
PubMed2006

Therapeutic implications of the specific inhibition of causative matrix metalloproteinases in experimental colitis induced by dextran sulphate sodium.

Extracellular matrix dynamics, crucial for tissue remodelling, are highly regulated by a cascade of matrix metalloproteinases (MMPs) during inflammation and wound healing processes in inflammatory bowel disease (IBD). Contrary to expectations, there are limited reports to date that MMP inhibitors have some beneficial therapeutic effects in experimental colitis models. Furthermore, clinical trials of MMP inhibitors against certain tumours have failed to show any therapeutic benefit. One major reason for this lack of success may be the apparent uncertainty about the precise spectrum of inhibitory activity required. Since tumour necrosis factor alpha (TNFalpha), a key mediator in colonic inflammation, promotes MMP production in a dose-dependent manner, the therapeutic success of anti-TNFalpha agents against IBD motivated us to re-evaluate the therapeutic potential of MMP inhibition. First, using a quantitative polymerase chain reaction (PCR), western blotting, and zymography, we determined which MMPs were relevant to experimental colitis induced in mice by dextran sulphate sodium. Next, we examined a distinct role for MAPK and NFkappaB signalling pathways in the regulation of the expression of these MMP genes. Finally, we examined whether transcriptional regulation of these MMPs, either indirectly using inhibitors of MAPK and/or NFkappaB signalling pathways or directly using siRNA directed against these MMPs, contributes to the prevention of colitis. Changes in the expression level of colonic MMP-3 and MMP-10 preceded the clinical course of colitis. Colitis improved in mice that received these signal inhibitors, together with suppression of MMP expression. Moreover, siRNA that targeted MMP-3 and MMP-10 effectively reduced both the transcription of these MMPs and the severity of colitis. We conclude that MMP-3 and MMP-10 play a causal role in excess tissue destruction in colitis. Specific inhibition of these MMPs should provide novel therapeutics against IBD.

Animals↗
PubMed2002

Immunomodulation of experimental colitis via caloric restriction: role of Nk1.1+ T cells.

Inflammatory bowel diseases are immune-mediated disorders. Dietary restriction and NK1.1+ liver-associated lymphocytes (LAL) are considered to be involved in immunomodulation of autoimmune diseases. Our aim was to evaluate the effect of caloric restriction on experimental colitis and to determine NK1.1+ LAL function in immunoregulation. Experimental colitis was induced in C57 black mice by intracolonic instillation of trinitrobenzene sulfonic acid. Caloric restriction to 60% of the daily requirement was started 2 weeks prior to, or simultaneously with, colitis induction and continued throughout the study. Control mice were fed ad libitum. Colitis was assessed by standard clinical and macroscopic scores. To determine the mechanism involved in immunomodulation, liver lymphocytes were isolated and analyzed for NK1.1+ T-cell markers by FACS. T-cell function was evaluated by T-cell proliferation. Serum cytokines were measured by ELISA. Dietary restriction to 60% markedly ameliorated experimental colitis in both groups. These mice gained weight and showed improved macroscopic parameters of colitis. NK1.1+ LAL numbers increased fourfold and NKT cytotoxicity twofold in caloric-restricted mice. The antigen-specific T-cell proliferation index decreased (from 4.45 in controls to 1.15), and IFN-gamma and IL-12 serum levels decreased (from 290 to 200 pg and from 122 to 53 pg, respectively) in caloric-restricted mice. Our conclusion was that dietary restriction induced immunomodulation of experimental colitis and ameliorated the disease. This effect was mediated via an increase in NK1.1+ T lymphocytes, which may play a critical role in keeping the T-cell balance in immunoregulation.

Animals↗
PubMed1998

Involvement of interleukin-1 in the development of ulcerative colitis induced by dextran sulfate sodium in mice.

Dextran sulfate sodium (DSS)-induced colitis in mice has been recognized as a model for human ulcerative colitis. Using this model, the effects of anti-murine interleukin 1beta (IL-1beta) antibodies (anti-muIL-1beta) and recombinant murine IL-1 receptor type I (rmuIL-1R) on the development of colitis were examined to determine whether IL-1 plays a role in colitis. Furthermore, RT-PCR amplification was used to examine for the presence of mRNAs for IL-1alpha and IL-1beta in the large intestine. In mice with colitis induced by DSS, administration of anti-muIL-1beta (5 mg/kg, once/week, i.p.) significantly suppressed body weight loss and shortening of the large intestine. Administration of rmuIL-1R (0.2 mg/kg or 1.0 mg/kg, once/day, i.v.) significantly suppressed shortening of the large intestine. Expression of mRNAs for IL-1alpha and IL-1beta was observed in the large intestine of mice which received distilled water containing 3% DSS for 5 days. The expression tended to increase in mice which received DSS for 11 days. In contrast, mRNA expression was not observed in mice which received distilled water without DSS. These results clearly demonstrate that IL-1 is involved in the development of DSS-induced colitis in mice and suggest that downregulation of IL-1 might be useful for the treatment of patients with ulcerative colitis.

Animals↗
PubMed1997

Acute experimental distal colitis alters colonic transit in rats.

Data from humans with active distal colitis suggest that the proximal colon exhibits increased contractile activity and delayed transit, whereas the distal colon shows decreased contractile activity and rapid transit. The present study used the acetic acid rat model of experimental colitis to determine the effect of distal colitis on total and regional colonic transit in vivo and on the in vitro contractility of circular smooth muscle from the proximal and distal colon. Distal colitis was induced in rats by intracolonic administration of 4% acetic acid; sham control rats received saline enemas. Control and colitic rats were studied 2 days postenemas. Total colon transit was determined by calculating the geometric center of distribution of a radiolabeled marker (51Cr) instilled into the proximal colon. Regional transit was assessed by expressing the radioactivity in the cecum, proximal and distal colon, and excreted stool as a percent of total radioactivity. Muscle strips from the proximal and distal colon were stimulated with 100 microM acetylcholine (ACh) and 60 mM KCl and the tension was expressed as kilograms per square centimeter. Distal colitis was characterized by decreased total colon transit, increased retention of marker in the cecum and proximal colon, and decreased retention of marker in the distal colon. In vitro contractility studies revealed that distal colitis increased proximal colon circular smooth muscle contractility and decreased distal colon circular smooth muscle contractility to both ACh and potassium. Distal colitis is associated with regional differences in colonic circular smooth muscle contractility, which may contribute to delayed transit in the proximal colon and rapid transit in the distal colon.

Acetylcholine↗
PubMed2001

Role of appendix and spleen in experimental colitis.

There is growing clinical evidence suggesting that certain secondary lymphoid tissues (e.g., appendix and spleen) contribute to the initiation and/or perpetuation of ulcerative colitis. In this study, the importance of secondary lymphoid tissues in inducing colitis was assessed experimentally by removing the spleen and/or appendix (or sham operation) prior to inducing colitis in mice. Feeding 2.5% dextran sulphate sodium (DSS) in drinking water over 7 days induced colitis. Clinical disease activity was assessed based on weight loss, stool consistency, and presence of blood in stools. Additional measurements included white blood cell count and hematocrit, and myeloperoxidase activity (MPO) in colon samples. Colonic injury was assessed by histology and computerized image analysis. DSS treatment in sham-operated mice produced colitis associated with weight loss, bloody diarrhea, and mucosal ulceration. Clinical assessment of DSS-treated mice subjected to appendectomy or combined appendectomy/splenectomy exhibited a delayed onset and course of disease activity. Histomorphologic examination revealed significantly lower damage scores and a reduction in ulcerated mucosal surface area. Colonic MPO activity, which correlated with tissue injury and disease activity, was lowest in appendectomized mice. No beneficial effects of splenectomy were observed after 7 days of colitis. These findings support the hypothesis that appendicular lymphoid tissue, but not the spleen, contributes to the development of colitis.

Animals↗
PubMed1988

Exaggerated prostaglandin production by colonic smooth muscle in rabbit colitis.

Enhanced production of arachidonic acid metabolites by colonic mucosa has been reported in ulcerative colitis as well as in experimental models of colitis. However, production of these compounds by colonic smooth muscle from colitis subjects has not been described. To evaluate arachidonic acid metabolism in colonic tissue, we studied the production of prostaglandin E2 (PGE2) by mucosa and muscularis propria in two experimental models of acute colitis in which inflammation was virtually confined to the mucosa. Colitis was induced in New Zealand white rabbits by either of two methods, dinitrochlorobenzene (DNCB) sensitization or formalin followed by intravenous soluble immune complexes (F-IC). Arachidonic acid metabolites were identified from in vitro incubations of tissue with [14C] arachidonic acid by thin layer chromatography followed by autoradiography. The major eicosanoid metabolites of colitis mucosa and muscularis were 14C-labeled prostaglandin E2, prostaglandin F2a and 6-keto prostaglandin F1 alpha. PGE2 was quantitated from incubations without labeled arachidonic acid by radio-immunoassay. PGE2, expressed as picograms per milligram protein per 20 min (mean +/- SEM), was increased in F-IC mucosa (1093 +/- 141 vs 645 +/- 189, P less than 0.05) and DNCB mucosa (1354 +/- 487 vs 527 +/- 222, P less than 0.05) compared to normals. PGE2 production by uninflamed colitis muscularis propria was also increased five- to eightfold compared to normals for F-IC muscularis (1594 +/- 329 vs 189 +/- 35, P less than 0.005) and DNCB muscularis (1287 +/- 171 vs 225 +/- 72, P less than 0.005). Thus, the adjacent inflammation in colonic mucosa may induce increased eicosanoid production by the uninflamed smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1988

Late presentation of ulcerative colitis in ex-smokers.

Details of the smoking history were obtained from 288 patients with ulcerative colitis who were more than 15 years of age when colitis developed. Men who had previously smoked presented with colitis at a later age than lifelong non-smokers (mean age difference 15.2 years). The proportion of ex-smokers in this group of patients with colitis was more than twice that expected in the general population. The interval between cessation of smoking and subsequent onset of colitis in ex-smokers was found to be relatively short and in two-thirds of patients occurred within seven years. A tentative model to explain the association between smoking and subsequent colitis is proposed. We suggest that whilst current smokers may have a lower incidence of colitis, ex-smokers appear to be at increased risk of developing the disease. An alternative explanation is that smoking may act in a manner analogous to sulphasalazine.

Adult↗
PubMed1990

Antiinflammatory effects of various drugs on acetic acid induced colitis in the rat.

The efficacy of various drugs used to treat ulcerative colitis, (sulfasalazine, 5-aminosalicylate, hydrocortisone) was investigated in a model of acetic acid-induced colitis in the rat. Subsequently, we tested the ability of antioxidant/5-lipoxygenase inhibitors (gossypol and nordihydroguiaretic acid [NDGA]) and a cyclooxygenase inhibitor (indomethacin) to attenuate the macroscopic colonic damage and/or neutrophil influx (myeloperoxidase activity [MPO]) associated with this model of colitis. Oral pretreatment with either sulfasalazine, gossypol, or NDGA significantly decreased colonic MPO activity induced by acetic acid. Intrarectal administration of such drugs resulted in an even larger reduction of the colonic inflammation, with gossypol being the most potent compound. Oral or intrarectal administration of corticosteroids (dexamethasone, hydrocortisone) also attenuated the parameters of acetic acid induced colitis. In contrast, pretreatment with indomethacin was ineffective, or when administered daily after colitis induction, indomethacin actually increased colonic neutrophil influx significantly. Our data suggest that both the route of drug administration and dosing regimen employed affect the antiinflammatory potency and/or efficacy of compounds on colitis induced by acetic acid in the rat. Drugs which were effective against this colitis may act by scavenging of oxygen derived free radicals.

Acetates↗
PubMed1994

Neutrophil-independence of the initiation of colonic injury. Comparison of results from three models of experimental colitis in the rat.

Although the role of neutrophils in the pathogenesis of several forms of gastrointestinal injury has been well demonstrated, their role in the development of experimental colonic injury is less clear. To examine whether neutrophils play a role in the development of experimental colitides, the effects of a sustained neutropenia on multiple indices of colonic injury in rats was examined 24 hr following the initiation of colitis with the intrarectal application of acetic acid, trinitrobenzene sulfonic acid (TNBS)-ethanol, or the potent proinflammatory agent, phorbol-12-myristate-13-acetate (PMA). In comparison to animals with normal neutrophil counts and colitis induced by any of the three agents, no attenuation in macroscopic damage or histopathologic injury was observed in neutropenic animals exhibiting a greater than 95% reduction in circulating neutrophils and 85% reduction in tissue-associated myeloperoxidase activity. Although the tissue edema associated with acetic acid or PMA-induced colitis was not reduced by neutropenia, the colonic edema associated with TNBS colitis was attenuated by prior neutrophil depletion with anti-neutrophil antiserum. Despite our initial hypothesis that neutrophils played a key role in the genesis of experimental colitis (especially that induced by PMA), the results demonstrated that these cells are not essential for the development of the major pathological features of colitis induced by this agent, acetic acid, or TNBS. Although these results support the proposal that in these models of colitis, inflammation develops secondary to injury (rather than the converse), further studies will be necessary to elucidate the role of inflammatory cells other than neutrophils in the genesis of experimental colitides.

Acetates↗