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PubMed1985

Carrageenan colitis in the guinea pig: pathological changes and the importance of ascorbic acid deficiency in disease induction.

In guinea pigs deprived of ascorbic acid, the oral administration of degraded E. spinosum carrageenan induced mild to moderate colitis, while E. cottonii consistently induced severe colitis. A variable degree of colitis was observed in scorbutic animals not receiving carrageenan. By contrast, in animals given large daily supplements of ascorbic acid, neither type of carrageenan consistently induced colitis and severe disease was rarely observed. The severe colitis induced by E. cottonii in scorbutic animals markedly affected the mid and distal colon and showed histological changes similar to human ulcerative colitis.

Animals↗
PubMed2002

Protective effects of neurokinin-1 receptor during colitis in mice: role of the epidermal growth factor receptor.

1. The role of substance P and its high affinity neurokinin-1 receptor in colitis has not been fully elucidated. We assessed the participation of neurokinin-1 receptor in colitis using the 2,4,6,-trinitrobenzensulphonic acid and dextran sulphate-induced animal models of colitis and genetically-engineered, neurokinin-1 receptor-deficient mice. 2. Clinical signs, macroscopic and histologic damage associated with 2,4,6,-trinitrobenzensulphonic acid (12 days) and dextran sulphate (5 days) colitis were more severe in neurokinin-1 deficient than in wild-type mice, while immunoreactivities for epidermal growth factor and its receptor were similar in the colon of both mice strains before and after colitis. 3. Substance P, dose-dependently induced intestinal fibroblast proliferation and enhanced epidermal growth factor-induced proliferation in intestinal fibroblasts isolated from wild-type, but not from neurokinin-1 receptor deficient mice. 4. Substance P-induced intestinal fibroblast proliferation required the presence of epidermal growth factor receptor with kinase activity. Furthermore, substance P induced epidermal growth factor tyrosine phosphorylation and activation in normal intestinal fibroblasts. 5. Our results indicate that in mice lacking the neurokinin - 1 receptor, substance P plays a protective role in prolonged experimental colitis.

Animals↗
PubMed2001

Dextran sulphate sodium-induced colitis is ameliorated in interleukin 4 deficient mice.

The importance of IL-4 and its effects in inflammatory bowel disease (IBD) was studied using the dextran sulphate sodium-induced model of experimental colitis. The model resembles ulcerative colitis in humans. IL-4 deficient mice and IL-4+/+ littermates were used to induce colitis. Activity of disease, extent of tissue damage, immunoglobulin isotypes, IFNgamma and IL-10 production was assessed. Both disease activity index (DAI) and histological scores were consistently lower in the IL-4 deficient mice than in the IL-4+/+ littermates. Furthermore, the lower histological scores reflected the milder inflammatory lesions and decreased ulceration found in the IL-4 deficient mice. Analysis of immunoglobulin subtypes showed that IgG1 was almost absent in the sera of IL-4 deficient mice. IFNgamma contents was much higher in colonic tissues from IL-4 deficient mice. Dextran sulphate sodium-induced colitis is ameliorated in IL-4 deficient mice. IL-4 either directly or through its effects on T and B cells influences its severity. It is unclear if the higher immunoglobulin-producing cells in the colonic tissues of IL-4 deficient mice before colitis was induced could have influenced the outcome of the disease. The high IFNgamma contents in colonic tissues of IL-4 deficient mice argue against the role of this cytokine as a crucial mediator of tissue damage during the acute phase of colitis.

Animals↗
PubMed1996

Sulphasalazine treatment and the colorectal mucosa-associated flora in ulcerative colitis.

AIM: To study the influence of sulphasalazine treatment on the mucosa-associated bacterial flora of rectal biopsy tissue specimens in patients with ulcerative colitis. PATIENTS: Twenty-four patients had newly diagnosed active ulcerative colitis; 20 patients had acute relapse of ulcerative colitis (10 not taking maintenance sulphasalazine); (40 patients had quiescent ulcerative colitis; 21 not taking maintenance sulphasalazine). The influence of 3 weeks of sulphasalazine treatment on the mucosa-associated flora was studied in the patients presenting with active disease. RESULTS: Comparison of patients according to sulphasalazine usage revealed few differences in the mucosal flora. In patients with quiescent ulcerative colitis, Escherichia coli was found at lower counts in patients taking maintenance sulphasalazine; however, this effect was not evident in patients with active disease. Inconsistent changes in other facultatives were seen between the two active disease groups, particularly for a miscellaneous group of unidentified Gram-positive rods. Three patients, all receiving sulphasalazine, were colonized with Clostridium difficile, but this did not appear to influence their disease. CONCLUSION: Sulphasalazine treatment in ulcerative colitis causes only minor disturbance to the populations of bacteria colonizing the colorectal mucosa.

Adult↗
PubMed1998

The effect of heparin on trinitrobenzene sulphonic acid-induced colitis in the rat.

BACKGROUND: Reduced blood coagulability seems to protect against inflammatory bowel disease; pilot studies using heparin in patients with inflammatory bowel disease have reported positive results. AIM: To evaluate the effects of heparin treatment on microangiographic and on inflammatory parameters in experimental colitis, induced by trinitrobenzene sulphonic acid (TNBS)-ethanol. METHODS: Four groups of rats: (i) controls (saline enema), TNBS-induced colitis with (ii) sham treatment (saline, s.c.), (iii) dexamethasone (0.25 mg/kg/day s.c.) and (iv) heparin (500 U/kg t.d.s., s.c.). Microangiography was performed 2 and 4 days after colitis induction. Partial thromboplastin time, colonic wet weight, macroscopic damage score and mucosal myeloperoxidase (MPO) activity were determined at day 4. RESULTS: TNBS-induced colitis caused a reduction in visible bowel wall vessels, which was prevented by heparin (P < 0.05) but not by steroids. The macroscopic damage scores and colon wet weights were similar in all colitis groups. Compared to untreated colitis the MPO activity in heparin-treated animals was of borderline significance. CONCLUSIONS: Heparin treatment improved microangiographic features and reduced inflammation to a certain degree. Steroids delayed development of colon hypoperfusion, but were ineffective on MPO activity. It remains to be determined if the observed effects are due to the antithrombotic activity of heparin or to an anti-inflammatory action.

Animals↗
PubMed1999

Depletion of colonic detoxication enzyme activity in mice with dextran sulphate sodium-induced colitis.

BACKGROUND: The increased risk of colonic malignancies in individuals with ulcerative colitis has prompted a search for early biomarkers of disease progression. AIM: To characterize Phase II detoxication enzyme expression during acute and chronic colitis. The mouse model of dextran sulphate sodium (DSS)-induced colitis represents a relevant system with which to sequentially evaluate the spectrum of biochemical changes associated with colorectal cancer risk. METHODS: Acute and chronic colitis were induced in Swiss Webster mice by administering DSS in the drinking water (5%) for 1-4 cycles. Each cycle consisted of 7 days DSS and 14 days of water. The glutathione S-transferase (GST) activity, gamma-glutamylcysteine synthetase (gamma-GCS) activity and glutathione content of the colonic tissues were determined at various time points throughout the experiment. Alterations in GST isozyme expression were confirmed by Western and Northern blot. RESULTS: GST activity was reduced significantly in the colon by the end of Cycle 1 (84% of control values). Specific activities continued to decrease with subsequent cycles of DSS exposure. By the end of Cycle 4, glutathione levels and gamma-GCS activity had reached 29% and 56% of control, respectively. CONCLUSIONS: These data suggest that detoxication enzyme depletion is associated with both acute and chronic colitis and may be an important event in the progression of ulcerative colitis to colon cancer.

Animals↗
PubMed2000

Limited exposure of the healthy distal colon to orally-dosed formulation is further exaggerated in active left-sided ulcerative colitis.

BACKGROUND: Active distal ulcerative colitis is often resistant to topically acting oral formulations. We speculated that the left side of the colon is underexposed to orally-dosed topical agents in patients with active distal colitis. METHODS: Twenty-two healthy volunteers (12 males, aged 22-47 years), and 10 patients (6 males, aged 33-73 years) with active left-sided ulcerative colitis ingested a Eudragit-coated gelatine capsule containing 111In-labelled amberlite resin on four successive days. Regional colonic distribution, transit times and percentage of daily dose resident were calculated from the average of four serial gamma camera images on the 4th day. RESULTS: (mean [95% CI]). When compared to controls, patients with colitis had significantly faster total colon transit (24.3 h [9.5-39.1] vs. 51.7 h [41.1-62.3]) as well as faster proximal colon transit (18.7 h [9.1-28.3] vs. 36.7 [28.5-44.9]), and distal colon transit (3.1 h [-0.5 to 6.8] vs. 15.0 h [10.5-19.5]), respectively (all P < 0.01). Material was asymmetrically distributed in health (proximal colon 69% [63-76] vs. distal colon 31% [24-37]). This asymmetry was more extreme in colitis, with corresponding values of 91% [85-96] vs. 9% [4-15]. As a result colitics had less material in the left-sided colon (9% [4-15] vs. 31% [24-37]), P < 0. 001. Colitics had a significantly lower percentage of the daily dose resident within the left side of the colon compared to controls (13% [-2 to 28] vs. 63% [44-81]), P < 0.01. CONCLUSIONS: Delayed release oral formulation is asymmetrically distributed within the colon in health. This asymmetry is exaggerated in active left-sided ulcerative colitis and, together with faster colonic transit, results in reduced exposure of the distal colon to orally-dosed topical agents.

Administration, Oral↗
PubMed2000

Nitric oxide mediates a therapeutic effect of nicotine in ulcerative colitis.

BACKGROUND: Ulcerative colitis is a condition of nonsmokers in which nicotine is of therapeutic benefit. AIMS: To examine the in vitro effect of nicotine on colonic smooth muscle activity and the role of nitric oxide (NO) as a mediator. METHODS: Nicotine, 1-10 microM, was administered to strips of circular muscle from the distal sigmoid colon of 9 patients with active ulcerative colitis and 18 with colorectal cancer. The effect of electrical field stimulation (EFS) was examined before nicotine was added. Finally L-NAME, a NO synthetase inhibitor, was added before nicotine was administered again. RESULTS: Muscle strips developed similar spontaneous resting tone. In response to EFS, ulcerative colitis tissue developed lower tensions than the controls. Nicotine significantly reduced the resting tone and peak tension after EFS, with a greater effect in controls. With L-NAME, peak tensions were increased more in ulcerative colitis than controls, and nicotine produced a much smaller reduction. CONCLUSIONS: Nicotine reduces circular muscle activity, predominantly through the release of nitric oxide-this appears to be 'up-regulated' in active ulcerative colitis. These findings may explain some of the therapeutic benefit from nicotine (and smoking) in ulcerative colitis and may account for the colonic motor dysfunction in active disease.

Adult↗
PubMed2001

Heparin and low-molecular-weight heparin (enoxaparin) significantly ameliorate experimental colitis in rats.

BACKGROUND AND AIMS: The anticoagulants, unfractionated heparin and low-molecular-weight heparin, demonstrated anti-inflammatory effects in animal models and in humans. Because of its dual effects, high-dose heparin was proposed as a therapeutic modality for ulcerative colitis. We investigated whether a low dose of low-molecular-weight heparin-enoxaparin (Clexane, Rhône-Poulenc Rorer, France)-ameliorates the inflammatory response in two models of experimental colitis. METHODS: Colitis was induced in rats by intrarectal administration of dinitrobenzene sulphonic acid. Enoxaparin (40, 80 and 200 microg/kg) or unfractionated heparin (100, 200 and 400 U/kg) were administered subcutaneously immediately after the induction of damage. Enoxaparin, 80 microg/kg, was also administered after induction of colitis by intrarectal administration of iodoacetamide. Rats were sacrificed 1, 3 or 7 days after induction of injury. Colonic damage was assessed macroscopically and histologically. Mucosal prostaglandin E2 generation, myeloperoxidase and nitric oxide synthase activities and tumour necrosis factor-alpha levels in blood were determined. RESULTS: Enoxaparin and heparin significantly ameliorated the severity of dinitrobenzene sulphonic acid- and iodoacetamide-induced colitis as demonstrated by a decrease in mucosal lesion area, colonic weight and mucosal myeloperoxidase and nitric oxide synthase activities. The dose-response curve had a bell-shaped configuration: enoxaparin, 80 microg/kg, and unfractionated heparin, 200 U/kg, were the optimal doses. CONCLUSIONS: Low-dose enoxaparin and unfractionated heparin ameliorate the severity of experimental colitis. This effect is related to their anti-inflammatory rather than anticoagulant properties.

Animals↗
PubMed2001

Effect of oral iron supplementation on oxidative stress and colonic inflammation in rats with induced colitis.

BACKGROUND: Iron supplementation may increase disease activity in ulcerative colitis, possibly through the production of reactive oxygen species from the Fenton reaction. AIM: To assess the effects of two doses of oral iron on intestinal inflammation and oxidative stress in experimental colitis. METHODS: Colitis was induced in rats by giving 5% dextran sulphate sodium in drinking water for 7 days. First, using a 2 x 2 factorial design, rats with or without dextran sulphate sodium received the regular diet or a diet containing iron 3%/kg diet. Second, rats with dextran sulphate sodium-induced colitis were supplemented with iron 0.3%/kg diet and compared with rats on dextran sulphate sodium and regular diet. The body weight change, histological scores, colon length, rectal bleeding, plasma and colonic lipid peroxides, colonic glutathione peroxidase and plasma vitamin E and C were measured. Faecal analysis for haem and total, free and ethylenediaminetetra-acetic acid-chelatable iron was also performed. RESULTS: Iron 3% and iron 0.3% increased the activity of dextran sulphate sodium-induced colitis, as demonstrated by higher histological scores, heavier rectal bleeding and further shortening of the colon. This was associated with increased lipid peroxidation and decreased antioxidant vitamins. Faecal iron available to the Fenton reaction was increased in a dose-dependent manner. CONCLUSIONS: Iron supplementation taken orally enhanced the activity of dextran sulphate sodium-induced colitis and is associated with an increase in oxidative stress.

Administration, Oral↗
PubMed2002

Long-term aminosalicylate therapy is under-used in patients with ulcerative colitis: a cross-sectional survey.

BACKGROUND: There is evidence from case-control studies that aminosalicylate drugs can reduce colorectal cancer risk by 75-81% in patients with ulcerative colitis. Patients may fail to comply with long-term therapies, however, or may have been advised to discontinue treatment once in remission. AIM: To describe the usage of long-term aminosalicylate therapy in patients with ulcerative colitis. METHODS: A cross-sectional study was performed using data extracted from general practitioner clinical records on demographic features, extent and duration of disease, use of aminosalicylate therapy and specialist care. RESULTS: Three hundred and sixty-three people had ulcerative colitis and no history of colorectal surgery. Ninety-five of 175 (54%) patients with proctitis, 78 of 123 (63%) patients with left-sided colitis and 28 of 45 (62%) patients with extensive colitis were currently taking an aminosalicylate drug. Those doing so were more likely to be under specialist care than to be definitely or possibly discharged (odds ratio, 4.9; 95% confidence interval, 2.9-8.4). The likelihood of current aminosalicylate therapy was not related to gender or the extent of disease, but was negatively related to the duration of disease. CONCLUSIONS: A substantial minority of patients with ulcerative colitis does not take long-term aminosalicylate therapy. Those who do are more likely to be under specialist care, to be older or to have disease of shorter duration.

Adult↗
PubMed1999

Fertility after ileal pouch-anal anastomosis in women with ulcerative colitis.

BACKGROUND: Women with ulcerative colitis are believed to have normal fertility but colectomy and ileal pouch-anal anastomosis (IPAA) may impair fertility. The aim was to compare fertility in patients with ulcerative colitis before and after IPAA with that in the national population. METHODS: Some 258 consecutive women who had undergone IPAA for ulcerative colitis were identified. Data were collected by questionnaire and from medical records. The observed number of births was compared with the number expected by indirect standardization by age and calendar year. Fertility from the age of 15 years to colectomy, from the onset of ulcerative colitis to colectomy, and from the 12 months after stoma closure to the time of data collection was investigated. RESULTS: A total of 237 women (92 per cent) responded. From the age of 15 years to colectomy there were 251 deliveries compared with an expected number of 286 (P < 0. 05). The number of births from the onset of ulcerative colitis to colectomy was 120, compared with an expected 131 (P > 0.3). From the 12 months after ileostomy closure until data collection there were 34 deliveries, compared with an expected 69 (P < 0.001). CONCLUSION: There is a considerable reduction in postoperative fertility after restorative surgery for ulcerative colitis.

Adult↗
PubMed1996

Efficacy of recombinant granulocyte colony-stimulating factor (rhG-CSF) in experimental colitis.

Inflammatory bowel disease is associated with mucosal neutrophil recruitment and activatation, mediated in part by arachidonic acid metabolites. G-CSF attenuates the immune response to sepsis and ameliorates glycogen storage disease Ib-related colitis. These actions may be effected through the shedding of neutrophil adhesion molecules, or inhibition of proinflammatory mediator synthesis. Immune complex colitis was used to evaluate the effect of rhG-CSF on colonic mucosal inflammation, neutrophil recruitment and the generation of eicosanoids. Immune complex colitis was induced in White New Zealand rabbits. Animals were pretreated with rhG-CSF either 24 h before induction, or at induction, with dosages of 50 and 200 micrograms/kg. rhG-CSF caused a time- and dose-dependent neutrophilia in all animals. Pretreatment with rhG-CSF resulted in increased tissue myeloperoxidase levels, despite a histologically similar mucosal polymorphonuclear cell infiltrate between treated and control colitis groups. Leukotriene B4 (LTB4) and thromboxane B2 (TXB2) dialysis fluid levels were lower in treated animals, in particular in the groups receiving two doses (LTB4: both P < 0.01; TXB2: both P < 0.01. Prostaglandin E2 (PGE2) levels in dialysis fluid of the rhG-CSF-treated animals showed no difference from controls. In this model of experimental colitis, high-dose therapy with G-CSF resulted in a marked decrease of proinflammatory mediators, but mucosal generation of the protective PGE2 was preserved. These results suggest that prolonged high-dose therapy with G-CSF may have anti-inflammatory effects in colitis.

Animals↗
PubMed2001

Oral administration of unmodified colonic but not small intestinal antigens protects rats from hapten-induced colitis.

Colonic administration of a hapten, 2,4,6-trinitrobenzene sulphonic acid (TNBS) has been shown to induce colitis in rats. We are using this model to investigate the role of colonic antigens in the immunopathology. In this study, we show that colitis can be suppressed by oral administration of haptenized colonic antigens prior to the TNBS enema. Moreover, our data suggest that haptenization of the colonic antigens is not essential because oral feeding of non haptenized colonic antigens too protects rats from TNBS-induced colitis. Thus, unmodified colonic antigens may be involved in the induction of oral tolerance, and possibly in the pathogenesis in this model of colitis. Further, we show that the protective immunity or oral tolerance induced by non haptenized colonic antigens can be passively transferred to naïve rats by mesenteric T lymphocytes. Interestingly, oral feeding of small intestinal antigens, haptenized and non haptenized, does not protect rats from colitis, suggesting a specific role for colonic antigens. These data underscore the usefulness of this rat model in the identification of pathogenic antigens in colitis and in the development of therapeutic strategies based on oral tolerance.

Administration, Oral↗
PubMed2000

Sensorineural hearing loss in ulcerative colitis.

Sensorineural hearing loss has been described in a small number of patients with ulcerative colitis. At present, it is not known whether this is a rare and sporadic association, or whether these reports represent an under recognised extra-intestinal manifestation of ulcerative colitis. The aim of this study was to determine the prevalence of hearing loss in patients with ulcerative colitis. Twenty patients with active ulcerative colitis (mean age 45 years) were recruited prospectively along with 20 healthy age- and sex-matched controls. Otoscopy, tympanometry and pure tone audiometry were performed. The activity of the disease was scored according to a 12-month cumulative disease activity index. No patients complained of auditory symptoms. Otoscopy and tympanometry were normal in all patients and controls. Pure tone audiometry showed significant sensorineural hearing loss over all frequencies in patients with ulcerative colitis compared with controls. This preliminary study indicates that subclinical sensorineural hearing loss is associated with ulcerative colitis. Further study is warranted to determine the nature of the relationship and its pathological basis.

Adult↗
PubMed2001

Macrophage migration inhibitory factor in the sera and at the colonic mucosa in patients with ulcerative colitis: clinical implications and pathogenic significance.

BACKGROUND: Inflammatory cytokines produced by activated macrophages are implicated in the pathogenesis of ulcerative colitis (UC). With the theory that macrophage migration inhibitory factor (MIF) may have a role in the accumulation of macrophages, we studied MIF in UC. MATERIALS AND METHODS: A total of 27 patients with UC, 14 patients with Crohn's diseases (CD), 11 patients with other forms of colitis and 26 normal controls were enrolled in the study. The levels of MIF in the sera and culture supernatant were measured by an enzyme-linked immunosorbent assay. MIF, macrophages and T cells were localized at the colonic mucosa by immunohistochemistry. RESULTS: The levels of MIF in the sera were significantly higher in UC than in normal controls (P < 0.05), in serum C-reactive protein (CRP) -positive cases with UC than in CRP-negative cases with UC (P < 0.05), and in patients with severe colitis with UC than in mild colitis with UC (P < 0.05). There was a positive relationship between serum MIF levels with the CRP levels and activities of colitis. However, the levels of MIF in patients with CD and other forms of colitis were not significantly different from their levels in normal controls and UC. Infiltrating cells at the colonic mucosa in UC and CD expressed MIF. CONCLUSIONS: These data suggest a role of MIF in the pathogenesis of UC. MIF may be used as a marker of disease activity in UC and control of MIF production may have therapeutic implications.

Adult↗
PubMed1999

Zinc sulphate solution enema decreases inflammation in experimental colitis in rats.

BACKGROUND: It has been reported that zinc sulphate contributes an anti-inflammatory action in many animal models; however, the impact of zinc in colitis remains unclear. The aim of the present study was to examine the role of zinc sulphate in experimental colitis. METHODS: Colitis was induced by 2,4,6-trinitrobenzenesulphonic acid (TNB) in rats. Beginning at the first day of TNB colitis, the rats were treated with a zinc sulphate enema once daily for 6 days. The rats were examined 8 days later. RESULTS: The TNB induced severe colitis as evidenced by increased mucosal lesion area, mucosal myeloperoxidase (MPO) activity and prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. Six days after the application of the zinc sulphate enema, the mucosal lesion area, MPO activity, PGE2 and LTB4 levels all decreased significantly. Mucosal superoxide dismutase activity remained unchanged after zinc treatments. CONCLUSIONS: Our data suggest that zinc sulphate enemas have an anti-inflammatory action on experimental colitis.

Animals↗
PubMed1996

Keratinocyte growth factor ameliorates mucosal injury in an experimental model of colitis in rats.

BACKGROUND & AIMS: Keratinocyte growth factor (KGF) is known to enhance tissue repair in the skin; however, its role in the gastrointestinal tract is largely unknown. The aim of this study was to evaluate the effects of exogenous KGF in an experimental model of colitis in rats. METHODS: KGF was administered before or after induction of colitis with 2,4,6-trinitrobenzenesulfonic acid/ethanol. In the first two study groups, KGF (5 mg/kg) was administered intraperitoneally 24 hours and 1 hour before induction of colitis; animals were killed 8 hours (n=10) and 1 week (n=10) after injury. In subsequent study groups, KGF or vehicle treatment was begun 24 hours after the induction of colitis at doses of 5 (n=20), 1 (n=10), and 0.1 (n=10) mg/kg intraperitoneally and continued once daily for 1 week. Colonic tissue samples were evaluated macroscopically and microscopically for mucosal injury and assayed for myeloperoxidase activity. RESULTS: Administration of KGF after but not before induction of colitis significantly ameliorated tissue damage. Macroscopic necrosis and microscopic ulcerations were reduced by 40%-50% at KGF doses of 1 and 5 mg/kg. CONCLUSIONS: Exogenous KGF has a key role in mucosal healing in an experimental model of colitis in rats.

Animals↗