Therapeutic effect of nimesulide on colorectal carcinogenesis in experimental murine ulcerative colitis

BACKGROUND: Patients with ulcerative colitis (UC) exhibit an increased risk for the development of cancer of the colon and rectum. Cyclooxygenase (COX)-2 inhibitors are known to suppress sporadic colorectal cancer, but it is unknown whether selective COX-2 inhibitors exhibit a preventive effect in UC-associated neoplasia. This study investigated the preventive effect of nimesulide, a selective COX-2 inhibitor, on colorectal carcinogenesis in an experimental model of murine UC. METHODS: Chronic colitis was induced in mice by administration of four cycles of dextran sulfate sodium (DSS) (each cycle: 5% DSS for 7 days and then distilled water for 14 days). The mice were killed 120 days after the completion of the fourth cycle. The mice were divided into the following five groups: group A served as a disease control; group B received a diet mixed with 400 p.p.m. of nimesulide during the whole period; group C received nimesulide during the four cycles of DSS administration (active phase); group D received nimesulide for 120 days from the end of the fourth cycle (remission phase); group E received no agents including DSS and served as a normal control. RESULTS: The incidence of dysplasia and/or cancer was 28%, 15%, 11.8%, 6.7% and 0% in groups A-E, respectively. In group D, nimesulide significantly suppressed the occurrence of dysplasia and/or cancer (P < 0.05). Strong COX-2 expression was detected by immunohistochemistry in cancer and dysplastic lesions while diffusely weak COX-2 expression was also found in the residual colon (i.e. lesion-free colon). The mucosal concentration of prostaglandin E(2) was significantly lower in groups B and D than in group A. CONCLUSIONS: The administration of the selective COX-2 inhibitor nimesulide (especially during the remission phase) exerts a suppressive effect on the development of dysplasia and/or cancer in a murine model of DSS-induced colitis. These findings may have relevance to long-standing UC in humans.     

Dysplasia and carcinoma development in a repeated dextran sulfate sodium-induced colitis model

BACKGROUND: As an important mechanism underlying the increased risk of colorectal carcinoma development in patients with long-standing ulcerative colitis, promotion as a result of the regenerative process has been proposed. In the present study, a dysplasia-carcinoma sequence in a novel repeated colitis model in mice is documented. METHODS: Repeated colitis was induced by nine administration cycles of 3% dextran sulfate sodium (DSS; molecular weight, 54 000): each administration cycle comprised 3% DSS for 7 days followed by distilled water for the subsequent 14 days, to give conditions similar to the clinically observed active and remission phases in humans. RESULTS: Multiple colorectal tumors (nine low- and four high-grade dysplasias and two carcinomas) developed in 25 mice. These neoplastic lesions consisted of tubular structures, presenting as various types of elevated, flat and depressed tumor, similar to those in ulcerative colitis patients. A time-course study with assessment of the severity of colitis and in vivo bromodeoxyuridine uptake during a single 3% DSS administration cycle revealed a high level of regenerative activity in the colitis-affected mucosal epithelia. CONCLUSION: Thus, with the present repeated colitis model, regeneration and neoplastic lesions were apparent, the biological features of which provide evidence of a colorectal dysplasia-invasive carcinoma sequence in ulcerative colitis.     

靛玉红对溃疡性结肠炎小鼠肠黏膜细胞因子含量的影响

[目的]探讨中药青黛有效成分靛玉红对溃疡性结肠炎(UC)小鼠肠黏膜细胞因子含量的影响.[方法]采用5％葡聚糖硫酸钠(DSS)建立UC小鼠模型,将小鼠随机分为靛玉红高、低剂量组,美沙拉嗪组,模型1、2组和正常组,每组10只.其中模型组于造模7d时处死,其余各组于第7d开始灌胃给药,连续给药7d时处死.ELISA法检测结肠...     

Effects of germinated barley foodstuff on dextran sulfate sodium-induced colitis in rats

Germinated barley foodstuff (GBF), derived from the aleurone and scutellum fractions of germinated barley, is rich in glutamine and low-lignified hemicellulose, and increases mucosal protein, RNA, and DNA content in the intestine when fed to normal rats. The aim of this study was to evaluate the effects of feeding GBF or germinated gramineous seeds on experimental ulcerative colitis. Sprague-Dawley rats that received 3% dextran sulfate sodium in their diets were used as an experimental colitis model. The effects of sulfasalazine, a drug used to treat inflammatory bowel disease, were compared with those of GBF. After rats had consumed diets containing GBF or various aleurone and scutellum fractions, mucosal damage; the content of mucosal protein, RNA, and DNA in the colo-rectum; and serum interleukin-8 and α₁-acid glycoprotein levels were assessed. GBF and germinated seeds more effectively prevented bloody diarrhea and mucosal damage in colitis compared with controls and rats receiving sulfasalazine, but non-germinated samples did not have a protective effect. GBF increased mucosal protein and RNA content in the colitis model. The consumption of GBF appears to prevent inflammation in a colitis model, and its effect seems to be related to the germination process. GBF and germinated seeds have the potential to serve as nutritional therapy for ulcerative colitis. (Received Mar. 17, 1997; accepted July 25, 1997)     

Changes of colonic vasoactive intestinal peptide and cholinergic activity in rats with chemical colitis

The vasoactive intestinal peptide concentration was examined in the colonic wall and portal venous plasma of rats with chemical colitis by radioimmunoassay, and the colonic localization was determined with immunocytochemistry. Colonic acetylcholine esterase activity was also measured, and the response of vasoactive intestinal peptide to acetylcholine administration was determined. Colitis was induced by administration of dextran sulfate for three months. The chemical colitis was histologically similar to active human ulcerative colitis. We observed a significant increase of immunostained neurons and nerve fibers and a significant rise in the colonic wall vasoactive intestinal peptide content in chemical colitis rats, while plasma concentrations of the peptide did not change significantly. Colonic acetylcholine esterase activity was significantly elevated in colitis rats compared with control rats. Systemic administration of acetylcholine significantly increased the colonic and plasma vasoactive intestinal peptide concentrations in colitis rats. These findings demonstrated a positive association between colitis activity and an increase of vasoactive intestinal peptide and suggested that increased vagal tone promoted the peptide's release.     

Effect of enteral nutrition on dextran sulfate sodium-induced colitis in rats

OBJECTIVE: To study the effect of enteral nutrition (EN) on dextran sulfate sodium (DSS)‐induced colitis in rats. METHODS: Eighty‐four Sprague–Dawley rats were divided into 7 groups (12 rats in each group). The blank control group was given ordinary laboratory feed and drinking water. The experimental groups received 5% DSS as drinking water for 7 days. Of the experimental groups, the model control group received ordinary laboratory feed, protein based enteral nutrition (PEN) was fed in the PEN group, while other groups received ordinary laboratory feed plus 5‐aminosalicylic acid (5‐ASA), methyl‐prednisolone, Lactobacillus or glutamine, respectively. On the 8th day, all the rats were sacrificed. Inflammatory scores were assessed from colonic mucosa. Blood culture from inferior vena cava, fecal culture and secretary immunoglobulin‐A (S‐IgA) levels from colonic contents were determined. RESULTS: Colon inflammatory scores of Lactobacillus, PEN, glutamine and drug‐treated groups were lower than that of the model control group (P < 0.01). The ratios of bacteria translocation in the EN (PEN, Lactobacillus and glutamine) groups were lower than that in the model control group (P < 0.0083). Fecal Lactobacilli in the Lactobacillus and glutamine groups were higher than that in the model control group (P < 0.05). S‐IgA levels in colonic contents of the PEN and 5‐ASA group were lower than that in the model control group (P < 0.05). CONCLUSIONS: EN is an effective therapy for treating DDS‐induced colitis. EN could alleviate damage, promote the repair of colonic epithelial cells and inhibit bacterial translocation. Lactobacillus and glutamine could also increase the Lactobacilli in colon.     

Dysplasia and cancer complicating strictures in ulcerative colitis

Previous studies have found a widely variable prevalence of dysplasia and cancer in colonic strictures in patients with ulcerative colitis. Consequently, therapeutic recommendations are conflicting. To better assess the prevalence, we reviewed the clinical and pathological findings in all 27 patients with ulcerative colitis complicated by stricture who were entered into our Inflammatory Bowel Disease Registry. A true stricture was defined as a persistant localized narrowing of the colon found on air-contrast barium enema or on colonoscopy. Upon careful review, 12 of 27 patients were found to have transient colonic spasm, not a stricture, and were excluded. The remaining 15 patients with true strictures represented 3.2% of all ulcerative colitis patients in the registry. Strictures were identified at 13.3± 9.9 years following the diagnosis of ulcerative colitis. Eleven patients had multiple strictures that were principally located in the left colon. Of the 15 patients, 11 had dysplasia and two had cancer found on colonoscopic biopsy. Ultimately, six patients had carcinoma found at colonoscopy or colectomy (three modified Dukes' stage A, one stage B, and two stage D). All cancers were at the site of a stricture. These findings indicate that a true colonic stricture in ulcerative colitis is frequently associated with dysplasia and cancer, which can be diagnosed with colonoscopic biopsy. A stricture should be considered a strong risk factor for cancer, requiring intensive colonscopic surveillance. If dysplasia is discovered, or if the stricture cannot be adequately biopsied, consideration should be given to total colectomy.Research supported by the David and Reva Logan Gastrointestinal Clinical Research Center and the Gastrointestinal Research Foundation Junior Board.     

Clinical significance of microsatellite instability in the inflamed mucosa for the prediction of colonic neoplasms in patients with ulcerative colitis

BACKGROUND AND AIM: Although molecular mechanisms underlying ulcerative colitis (UC)-associated neoplasms have been studied for years, understanding of these mechanisms remains incomplete and no good predictable marker for development of colonic neoplasms in patients with UC has been established. The aim of this study was to assess if microsatellite instability (MSI) contributes to the development of colonic neoplasms in patients with UC. METHODS: We have examined MSI in chronic inflamed and neoplastic colonic mucosa of UC patients. We have also obtained serial biopsied colonic tissues retrospectively 2-12 years before the final diagnosis from patients with high level MSI (MSI-H+) UC-associated neoplasms, and analyzed MSI using them at different periods. RESULTS: Eight of 12 UC-associated colon cancers (67%), four of six UC-associated high grade dysplasias (67%), and two of six UC-associated low grade dysplasias (33%) revealed MSI-H+ phenotypes. In contrast, 15 of 59 lesions (25%) in inflamed UC mucosa without colonic neoplasm revealed MSI-H +. Interestingly, all four patients with MSI-H+ phenotypes at the final diagnosis of UC-associated colon cancer or dysplasia had already had MSI-H+ at the stage of chronic colitis, 2-12 years before the final diagnosis. CONCLUSION: These results support the notion that MSI contributes to the carcinogenesis of UC-associated neoplasms, and indicate that this analysis in inflamed colonic mucosa at surveillance colonoscopy is useful for identifying UC patients who have high risk for neoplastic progression.     

Hemodynamics in the colonic mucosa of rats with dextran sulfate-induced colitis in the early phase

We investigated hemodynamics in the colonic mucosa of rats with experimental colitis induced by the administration of dextran sulfate sodium (DSS). As parameters of hemodynamics, we determined the indices of mucosal hemoglobin concentration (IHb) and mucosal oxygen saturation (ISO₂), measured by reflectance spectrophotometry, and an index of colonic mucosal blood flow (Flow), measured by laser-Doppler flowmetry. In the ascending colon, each parameter was measured by a combination of these methods after 1, 3, 5, 7, and 10 days of DSS administration. Histopathological examination was also performed. IHb in the DSS group increased with time; on the 7th day, the value was 126.9±8.32, while that in the control group was 85.0±4.14, IHb in the DSS group being significantly increased (P<0.02). ISO₂ in the DSS group was lower than that in the control group, and on the 7th day, was significantly lower in the DSS group (25.7±1.34) than in the control group (33.4±1.77) (P<0.01). No changes in Flow were observed in either the DSS or the control group during the administration period, and no significant difference in Flow was found between the two groups. On histopathological examination, we observed a time-dependent increase in the infiltration of inflammatory cells in the ascending colon of rats treated with DSS, but changes such as erosion and ulceration were not found in the superficial layer of the mucosa. No histopathological changes were found in the control animals. In the early phase of the experimental colitis, hemodynamic alterations in the colonic mucosa were already present at the time the slight histopathological changes developed. These observations seemed to indicate the involvement of hemodynamic alterations in the subsequent tissue injury.     

Compensatory response of colon tissue to dextran sulfate sodium-induced colitis

Depletion of goblet cells (the main mucin-producing cells in the colon) is one of the most reliable histological characteristics of ulcerative colitis, whereas a major symptom of this disease is bloody diarrhea containing a large amount of mucus. The discrepancy between these phenomena was investigated in a time-course study in rats with experimental colitis induced by treatment with oral dextran sulfate sodium (DSS) for 1, 3, or 5 days. Biochemical analysis showed a reduction in mucin content in the distal side of the colon that was proportional to the duration of DSS administration. In the proximal side of the colon, however, there was a significant increase in mucin content already on the first day of treatment with DSS. This increase in colonic mucin content continued for the 5 days of treatment. In the distal side, both sulfomucin and sialomucin decreased proportionally to the duration of DSS administration. In the proximal side, there was an increase in high iron diamine-Alcian blue-positive mucins, and confirming the proliferation of goblet cells. The proliferated glands were predominantly sialylated. Goblet cell depletion and an increase in mucin production occurred in different parts of the colon. This phenomenon may be a type of compensatory function of colon tissue in response to the localized decrease of mucin production in certain portions of the colon. (Received Sept. 7, 1998; accepted Nov. 27, 1998)     

Studies on changes of colonic mucosal PGE2 levels and tissue localization in experimental colitis

Experimental ulcerative colitis was produced in rats and the changes of PGE₂ levels in the colonic mucosa and the tissue localization of PGE₂ were studied immunohistochemically during the process of onset and healing of the experimental lesions. Compared with that in controls, PGE₂ levels in colonie mucosa were not significantly higher in the early stage of inflammation, but rose gradually with exacerbation of inflammation, and after reaching peak values at the peak stage of development of colitis, decreased as signs of inflammation receded. Immunohistochemical study of the normal rat colon showed that PGE₂ was uniformly positive in the muscularis mucosa and in the tunica propria muscularis adjacent to the submucosal layer. Furthermore, as the inflammation progressed infiltrating inflammatory cells also became positive, especially macrophages. These changes decreased along with regeneration of the epithelium and resolution of the inflammation. Glandular epithelial cells did not show positivity. These results made it clear that the PGE₂ level in colonie mucosa is an useful index of the activity of colitis and that changes in PGE₂ levels are associated with infiltration by inflammatory cells, principally macrophages, of the interstitium. The results also suggested the possibility that the muscularis mucosa plays a role in the colonie mucosal protective system.     

Low incidence of colorectal dysplasia and cancer among patients with ulcerative colitis: A Turkish referral centre study

Abstract

Objectives. To determine the incidences of dysplasia, adenomatous polyp and colon cancer in patients with ulcerative colitis (UC) and to evaluate the risk factors. Material and methods. We retrospectively reviewed the medical records of patients with UC admitted to the Turkiye Yuksek Ihtisas Hospital between 1994 and 2008 and who subsequently developed colorectal cancer (CRC). Results. Between 1994 and 2008, a total of 844 UC patients were followed in our clinic. A total of 275 patients entered our surveillance programme. The duration of UC was as follows: 10–15 years, n = 173 (62.9%); 15–20 years, n = 55 (20.0%); 20–25 years, n = 26 (9.5%), 25–30 years, n = 9 (3.3%); and >?30 years, n = 12 (4.4%). In terms of localization, 80 patients (29.1%) had distal disease, 107 (38.9%) had left-sided disease and 88 (32.0%) had extensive colitis. Adenomatous polyp was found in six patients (2.2%). Five cases (83.3% of the polyps) were in the diseased segment and one case (16.7%) was in the non-diseased segment. Endoscopy revealed dysplasia in 11 cases (4.0%). Of the 275 UC patients, CRC was diagnosed in only three (1.1%) during follow-up. Adenomatous polyp was not found in cases with colon cancer. Conclusions. In our cases with UC, rates of dysplasia and CRC were much lower than in other reports. The difference in rates may be explained by racial factors, specific environmental factors, intensive control of disease activity through medical therapy and effective colonoscopic surveillance programmes.     

Inhibition of neutrophil elastase prevents the development of murine dextran sulfate sodium-induced colitis

Background Neutrophil elastase (NE) is a major secretory product from activated neutrophils and a major contributor to tissue destruction. However, little is known about the pathogenic contribution of NE to ulcerative colitis (UC). This study was designed to investigate the contribution of NE by measuring NE activity in plasma and colonic mucosal tissue from UC patients and a murine acute colitis model, and to elucidate the therapeutic effect of the NE-specific inhibitor ONO-5046. Methods The NE enzyme activities in plasma and colonic mucosal tissue from UC patients were directly measured using an enzyme–substrate reaction. Acute colitis was induced in mice by administration of 1.5% dextran sulfate sodium (DSS) for 5 days. DSS-induced colitis mice were then treated with ONO-5046 (50 mg/kg body weight) intraperitoneally twice a day. Results In UC patients, the NE enzyme activity was significantly elevated in both the plasma and colonic mucosal tissue compared with healthy controls. In DSS-induced colitis mice, the NE enzyme activity increased in parallel with the disease development. ONO-5046 showed therapeutic effects in DSS-treated mice by significantly reducing weight loss and histological score. ONO-5046 suppressed the NE enzyme activities in both plasma and culture supernatant of colonic mucosa from DSS-induced colitis mice. Conclusions ONO-5046, a specific NE inhibitor, prevented the development of DSS-induced colitis in mice. NE therefore represents a promising target for the treatment of UC patients.     

Butyrate and glucose metabolism by colonocytes in experimental colitis in mice

BACKGROUND/AIMS: Impaired colonocyte metabolism of butyrate has been implicated in the aetiopathogenesis of ulcerative colitis. Colonocyte butyrate metabolism was investigated in experimental colitis in mice. METHODS: Colitis was induced in Swiss outbred white mice by oral administration of 4% dextran sulphate sodium (DSS). Colonocytes isolated from colitic and normal control mice were incubated with [(14)C]butyrate or glucose, and production of (14)CO(2), as well as of intermediate metabolites (acetoacetate, beta-hydroxybutyrate and lactate), was measured. The effect of different substrate concentrations on oxidation was also examined. RESULTS: Butyrate oxidation (micromol/h per mg protein; mean (SEM)) was significantly reduced in DSS colitis, values on day 7 of DSS administration being 0.177 (0.007) compared with 0.406 (0.035) for control animals (p<0.001). Glucose oxidation (micromol/h per mg protein; mean (SEM)) on day 7 of DSS administration was significantly higher than in controls (0.06 (0.006) v 0.027 (0.004), p<0.001). Production of beta-hydroxybutyrate was decreased and production of lactate increased in DSS colitis compared with controls. Increasing butyrate concentration from 10 to 80 mM enhanced oxidation in DSS colitis (0.036 (0.002) to 0.285 (0.040), p<0.001), although it continued to remain lower than in controls. Surface and crypt epithelial cells showed similar ratios of butyrate to glucose oxidation. When 1 mM DSS was added to normal colonocytes in vitro, it did not alter butyrate oxidation. The initial histological lesion of DSS administration was very patchy and involved crypt cells. Abnormal butyrate oxidation became apparent only after six days of DSS administration, at which time histological abnormalities were more widespread. CONCLUSIONS: Colonocyte metabolism of butyrate, but not of glucose, is impaired in DSS colitis, and may be important in pathophysiology. Histological abnormalities preceded measurable defects in butyrate oxidation.     

Telomere shortening in the colonic mucosa of patients with ulcerative colitis

Telomere length in human somatic cells gradually decreases with the number of cell divisions and is regarded as a marker of somatic cell turnover. Mucosal cells of the affected colon show rapid turnover in individuals with active ulcerative colitis (UC). Telomere length was determined by Southern blot analysis of terminal restriction fragments (TRFs) from the colonic mucosa of 17 patients with UC in remission, two of whom showed dysplasia, and 17 control subjects without colitis. For each individual, mean TRF length was compared between rectal mucosa and unaffected cecal mucosa. The mean TRF length of the rectal mucosa was significantly less than that of cecal mucosa in UC patients (7.87 ± 0.36 kb versus 8.77 ± 0.21 kb; P = 0.0015, Wilcoxon signed rank test), whereas no significant difference was detected in the control subjects. The extent of telomere shortening was 10.6 ± 3.35% in UC patients, compared with 0.8 ± 0.64% in noncolitis controls (P = 0.0024, Mann-Whitney U-test). Four UC patients, two of whom had dysplasia, showed telomere shortening of more than 20% in the rectal mucosa. These observations suggest that telomere shortening in the colonic mucosa of individuals with UC may represent the history of mucosal inflammation during disease of long duration, and that it may contribute to aneuploidy in UC. (Received May 6, 1997; accepted Sept. 26, 1997)     

Influences of the colonic microbiome on the mucous gel layer in ulcerative colitis

The colonic mucus gel layer (MGL) is a critical component of the innate immune system acting as a physical barrier to microbes, luminal insults, and toxins. Mucins are the major component of the MGL. Selected microbes have the potential to interact with, bind to, and metabolize mucins. The tolerance of the host to the presence of these microbes is critical to maintaining MGL homeostasis. In disease states such as ulcerative colitis (UC), both the mucosa associated microbes and the constituent MGL mucins have been shown to be altered. Evidence is accumulating that implicates the potential for mucin degrading bacteria to negatively impact the MGL and its stasis. These effects appear more pronounced in UC.   This review is focused on the host-microbiome interactions within the setting of the MGL. Special focus is given to the mucolytic potential of microbes and their interactions in the setting of the colitic colon.     

Cancer surveillance in ulcerative colitis: critical analysis of long-term prospective programme

BACKGROUND: Patients with longstanding ulcerative colitis are at increased risk of colorectal cancer. In the literature, no agreement has yet been reached regarding prevention strategies. Our report sums up a prospective study started in 1980. METHODS: A total of 65 patients affected by ulcerative colitis for more than seven years were admitted to a regular colonoscopic and biopsy follow-up programme. RESULTS: Some 20 years after the beginning of the study, 23 (35.3%) patients have been operated upon, 2 patients have died but not from cancer 29 (44.66%) patients have abandoned the programme. Only 11 (16.9%) patients have remained under colonoscopic surveillance. CONCLUSION: These results cast some doubts on the significance of such a programme and on its long-term feasibility.     

Dextran Sulfate Sodium-Induced Colitis in Immunodeficient Rats

To examine the morphology of colitis and study the role of the immune system in colitis, we compared colitis in immunocompetent Wistar-Kyoto rats with that in spontaneously hypertensive rats, known to have T-cell dysfunction. Rats were treated with 3% dextran sulfate in drinking water for periods ranging from 3 to 60 days. Diarrhea developed earlier and was associated with a more severe weight loss in Wistar-Kyoto rats than spontaneously hypertensive rats. The morphologic findings (flattening of the gland epithelium, gland dropout and ulceration) in spontaneously hypertensive rats were milder than in Wistar-Kyoto rats. Only spontaneously hypertensive rats survived 60 days of treatment; the findings included ulceration, crypt distortion, and inflammatory pseudopolyp formation. Immunostaining for B-cell, T-cell, and macrophage markers showed no difference in the distribution of these cells in the mucosa of Wistar-Kyoto rats and spontaneously hypertensive rats. Spontaneously hypertensive rats with T-cell dysfunction develop dextran sulfate sodium-induced colitis.