Mesalamine blocks tumor necrosis factor growth inhibition and nuclear factor kappaB activation in mouse colonocytes.
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BACKGROUND & AIMS: Derivatives of 5-aminosalicylic acid (mesalamine) represent a mainstay in inflammatory bowel disease therapy, yet the precise mechanism of their therapeutic action is unknown. Because tumor necrosis factor (TNF)-alpha is important in the pathogenesis of inflammatory bowel disease, we investigated the effect of mesalamine on TNF-alpha-regulated signal transduction and proliferation in intestinal epithelial cells. METHODS: Young adult mouse colon cells were studied with TNF-alpha, epidermal growth factor, or ceramide in the presence or absence of mesalamine. Proliferation was studied by hemocytometry. Mitogen-activated protein (MAP) kinase activation and IkappaBalpha expression were determined by Western blot analysis. Nuclear transcription factor kappaB (NF-kappaB) nuclear translocation was determined by confocal laser immunofluorescent microscopy. RESULTS: The antiproliferative effects of TNF-alpha were blocked by mesalamine. TNF-alpha and ceramide activation of MAP kinase were inhibited by mesalamine, whereas epidermal growth factor activation of MAP kinase was unaffected. TNF-alpha-stimulated NF-kappaB activation and nuclear translocation and the degradation of Ikappa-Balpha were blocked by mesalamine. CONCLUSIONS: Mesalamine inhibits TNF-alpha-mediated effects on intestinal epithelial cell proliferation and activation of MAP kinase and NF-kappaB. Therefore, it may function as a therapeutic agent based on its ability to disrupt critical signal transduction events in the intestinal cell necessary for perpetuation of the chronic inflammatory state. (+info)
Intestinal metabolism and transport of 5-aminosalicylate.
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The purpose of this study was to determine the characteristics of intestinal absorption and metabolism of 5-aminosalicylic acid (5ASA). Regional perfusions of 5ASA in the anesthetized rat resulted in the appearance of N-acetyl-5-aminosalicylic acid in the intestinal lumen. Lumenal metabolite appearance was proportional to 5ASA permeability, which was 5-fold higher in the jejunum than in the ileum. Intestinal elimination significantly decreases 5ASA absorption at low lumenal drug concentrations and this process is saturated at high drug concentrations. Metabolite levels in intestinal tissue were higher than plasma levels at low perfusion drug concentrations, whereas the reverse was observed at high concentrations. Transport and metabolism of 5ASA was studied in Caco-2 monolayers. At low drug concentrations, 5ASA was preferentially transported in the basolateral (BL) to apical (AP) direction. With 5ASA incubation in either the AP or BL chamber, the N-acetyl metabolite appeared only in the AP compartment. Transport of N-acetyl-5-aminosalicylic acid was also exclusively observed in the BL to AP direction. Clinical data indicate that anti-inflammatory response to oral 5ASA correlates with the amount of 5ASA delivered to the intestinal tissue. This study shows that at lumenal levels below 200 microg/ml (concentrations that are typically achieved by controlled release dosage forms), intestinal secretion of 5ASA accounts for more than 50% of the total elimination and can significantly affect tissue levels and, therefore, may be an important factor in determining the response to 5ASA therapy. (+info)
The systemic load and efficient delivery of active 5-aminosalicylic acid in patients with ulcerative colitis on treatment with olsalazine or mesalazine.
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BACKGROUND: There have been reports of nephrotoxic reactions in patients with ulcerative colitis treated with 5-aminosalicylic acid (5-ASA) preparations. AIM: To compare the efficacy in delivery of active 5-ASA to the colon and the systemic load as the basis for potential long-term toxicity during treatment with olsalazine or mesalazine in patients with ulcerative colitis in remission. PATIENTS AND METHODS: Fifteen patients with ulcerative colitis were treated with olsalazine or mesalazine, each for 7 days in an open, randomized, crossover design study. 5-ASA and acetyl-5-ASA (Ac-5-ASA) in plasma and urine were measured by high performance liquid chromatography. RESULTS: The plasma concentration of 5-ASA was 1.2 +/- 0.1 micromol/L (mean +/- S.E.M.) for olsalazine and 8.0 +/- 1.9 micromol/L for mesalazine, while the plasma concentration of Ac-5-ASA was 2.8 +/- 0.2 micromol/L for olsalazine and 10.8 +/- 1.6 micromol/L for mesalazine. The amount of 5-ASA excreted in the urine was 68 +/- 30 micromol/24 h for olsalazine and 593 +/- 164 micromol/24 h for mesalazine. The amount of Ac-5-ASA in the urine was 1260 +/- 102 micromol/24 h for olsalazine and 3223 +/- 229 micromol/24 h for mesalazine. The urinary recovery of total 5-ASA plus Ac-5-ASA (as a percentage of the given dose) was 23 +/- 2.1% for olsalazine and 39 +/- 3.6% for mesalazine. The ratio between the plasma concentrations of mesalazine and olsalazine differed significantly both for 5-ASA (5.1) and Ac-5-ASA (3.6); for 5-ASA (9. 9) and Ac-5-ASA (2.6) in urine, and for the urinary recovery of total 5-ASA plus Ac-5-ASA (1.7). Moreover, in the mesalazine group there was a large variation in the individual plasma concentrations of 5-ASA and Ac-5-ASA, with maximal values 5-6-fold higher than that in the olsalazine group. CONCLUSION: The systemic load of active 5-ASA is significantly higher for mesalazine than for olsalazine, when based on the dosages given and when calculated on an equimolar basis. Some of the patients in the mesalazine group showed unexpected high levels of plasma and urinary 5-ASA concentrations, a finding which may have long-term safety implications. (+info)
Antioxidant effects of aminosalicylates and potential new drugs for inflammatory bowel disease: assessment in cell-free systems and inflamed human colorectal biopsies.
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BACKGROUND: The therapeutic efficacy of 5-aminosalicylic acid in inflammatory bowel disease may be related to its antioxidant properties. AIM: To compare in vitro the antioxidant effects of conventional drugs (5-aminosalicylic acid, corticosteroids, metronidazole), with new aminosalicylates (4-aminosalicylic acid, balsalazide) and other potential therapies (ascorbate, N-acetylcysteine, glutathione, verapamil). METHODS: Compounds were assessed for efficacy in reducing the in vitro production of reactive oxygen species by cell-free systems (using xanthine/xanthine oxidase, with or without myeloperoxidase) and by colorectal biopsies from patients with ulcerative colitis using luminol-amplified chemiluminescence. RESULTS: 5-aminosalicylic acid and balsalazide were more potent antioxidants than 4-aminosalicylic acid or N-acetyl-5-aminosalicylic acid in cell-free systems. 5-aminosalicylic acid (20 mM) and balsalazide (20 mM) inhibited rectal biopsy chemiluminescence by 93% and 100%, respectively, compared with only 59% inhibition by 4-aminosalicylic acid (20 mM). Hydrocortisone, metronidazole and verapamil had no significant effect on chemiluminescence in any system. Ascorbate (20 mM) inhibited chemiluminescence by 100% in cell-free systems and by 60% in rectal biopsies. N-acetyl cysteine (10 mM), and both oxidized and reduced glutathione (10 mM), completely inhibited chemiluminescence in cell-free systems, but not with rectal biopsies. CONCLUSIONS: The antioxidant effects of compounds varies between cell-free systems and inflamed colorectal biopsies. The effect of drugs on the chemiluminescence produced by these two assay systems is useful for screening potentially new antioxidant treatments for inflammatory bowel disease. Ascorbate seems worth further study as a novel therapy. (+info)
Is maintenance therapy always necessary for patients with ulcerative colitis in remission?
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BACKGROUND: The efficacy of sulphasalazine and mesalazine in preventing relapse in patients with ulcerative colitis is well known. It is less clear how long such maintenance should be continued, and if the duration of disease remission is a factor that affects the risk of recurrence. AIM: To determine whether the duration of disease remission affects the relapse rate, by comparing the efficacy of a delayed-release mesalazine (Asacol, Bracco S.p.A., Milan, Italy) against placebo in patients with ulcerative colitis with short- and long-duration of disease remission. METHODS: 112 patients (66 male, 46 female, mean age 35 years), with intermittent chronic ulcerative colitis in clinical, endoscopic and histological remission with sulphasalazine or mesalazine for at least 1 year, were included in the study. Assuming that a lower duration of remission might be associated with a higher relapse rate, the patients were stratified according to the length of their disease remission, prior to randomization into Group A (Asacol 26, placebo 35) in remission from 1 to 2 years, or Group B (Asacol 28, placebo 23) in remission for over 2 years, median 4 years. Patients were treated daily with oral Asacol 1.2 g vs. placebo, for a follow-up period of 1 year. RESULTS: We employed an intention-to-treat analysis. In Group A, whilst no difference was found between the two treatments after 6 months, mesalazine was significantly more effective than placebo in preventing relapse at 12 months [Asacol 6/26 (23%), placebo 17/35 (49%), P = 0.035, 95% Cl: 48-2.3%]. In contrast, in Group B no statistically significant difference was observed between the two treatments, either at 6 or 12 months [Asacol 5/28 (18%), placebo 6/23 (26%), P = 0.35, 95% Cl: 31-14%] of follow-up. Patients in group B were older, and had the disease and remission duration for longer, than those in Group A. CONCLUSIONS: Mesalazine prophylaxis is necessary for the prevention of relapse by patients with ulcerative colitis in remission for less than 2 years, but this study casts doubt over whether continuous maintenance treatment is necessary in patients with prolonged clinical, endoscopic and histological remission, who are at very low risk of relapse. (+info)
A new mesalazine gel enema in the treatment of left-sided ulcerative colitis: a randomized controlled multicentre trial.
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BACKGROUND: A new mesalazine rectal gel preparation (without propellant gas) has been recently developed to improve topical treatment in distal ulcerative colitis. AIM: To evaluate the efficacy, safety and patient tolerability of mesalazine gel enema compared with mesalazine foam enema in the treatment of patients with acute left-sided ulcerative colitis. METHODS: In a randomized multicentre investigator-blind parallel group trial, 103 patients with mild to moderate left-sided colitis or proctosigmoiditis were randomly allocated to mesalazine 2 g gel enema (n = 50 evaluable patients) and mesalazine 2 g foam enema (n = 53 evaluable patients) for 4 weeks. Clinical symptoms, endoscopic and histological findings were assessed at entry, 2 and 4 weeks. Patients' evaluation of treatment tolerability and acceptability was assessed at 2 and 4 weeks. RESULTS: After 4 weeks of treatment, clinical remission was achieved by 76% of mesalazine gel enema-treated patients and 69% of patients treated with mesalazine foam enema (P = 0.608). Endoscopic remission rates at week 4 were 51 and 52% for the mesalazine gel and foam enemas, respectively (P = 0.925). Histological remission was achieved by 30% of patients in both groups. Patients reported that the new mesalazine gel preparation was significantly better tolerated than the foam enema. Patients in the foam group had significantly more difficulty in retention (25% vs. 6%, P < 0.05), abdominal bloating (50% vs. 26%, P < 0.005) and discomfort during administration (48% vs. 26%, P < 0.05). CONCLUSION: The new mesalazine gel enema is efficacious and significantly better tolerated than the mesalazine foam enema. (+info)
Evaluation of 5-aminosalicylic acid (5-ASA) for cancer chemoprevention: lack of efficacy against nascent adenomatous polyps in the Apc(Min) mouse.
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Recent experimental and epidemiological evidence suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) are effective in the prevention of colorectal cancer. However, the toxicity associated with the long-term use of most classical NSAIDs has limited their usefulness for the purpose of cancer chemoprevention. Inflammatory bowel disease (IBD) patients, in particular, are sensitive to the adverse side effects of NSAIDs, and these patients also have an increased risk for the development of intestinal cancer. 5-Aminosalicylic acid (5-ASA) is an anti-inflammatory drug commonly used in the treatment of IBD and may provide protection against the development of colorectal cancer in these patients. To directly evaluate the ability of 5-ASA to suppress intestinal tumors, we studied several formulations of 5-ASA (free acid, sulfasalazine, and Pentasa) at multiple oral dosage levels [500, 2400, 4800, and 9600 parts/million (ppm)] in the adenomatous polyposis coli (Apc) mouse model of multiple intestinal neoplasia (Min). Although the ApcMin mouse is not a model of colitis-associated neoplasia, it is, nonetheless, a useful model for assessing the ability of anti-inflammatory agents to prevent tumor formation in a genetically preinitiated population of cells. We used a study design in which drug was provided ad libitum through the diet beginning at the time of weaning (28 days of age) until 100 days of age. We included 200 ppm of piroxicam and 160 ppm of sulindac as positive controls, and the negative control was AIN-93G diet alone. Treatment with either piroxicam or sulindac produced statistically significant reductions in intestinal tumor multiplicity (95% and 83% reductions in tumor number, respectively; P < 0.001 versus controls). By contrast, none of the 5-ASA drug formulations or dosage levels produced consistent dose-progressive changes in polyp number, distribution, or size, despite high luminal and serum concentrations of 5-ASA and its primary metabolite N-acetyl-5-ASA. Thus, 5-ASA does not seem to possess direct chemosuppressive activity against the development of nascent intestinal adenomas in the ApcMin mouse. However, because intestinal tumor development in the ApcMin mouse is driven by a germline mutation in the Apc gene rather than by chronic inflammation, we caution that these findings do not definitively exclude the possibility that 5-ASA may exert a chemopreventive effect in human IBD patients. (+info)
Prevention of post-operative recurrence of Crohn's disease requires adequate mucosal concentration of mesalazine. Gruppo Italiano per lo Studio del Colon e del Retto.
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BACKGROUND: Surgical resection of Crohn's disease is followed by early recurrence in a high percentage of patients. Mesalazine has been shown to be effective in the prevention of post-operative recurrence, but some 50% of patients under treatment recur at 3 years of follow-up. AIM: To establish whether the mucosal concentration of mesalazine might affect the development of post-operative recurrence. METHODS: Colon-ileoscopy was performed in 25 consecutive patients resected for Crohn's disease. The mean time from surgery was 14 months. After the operation, all patients were taking oral mesalazine (Asacol, 2.4 g/day). Ten patients showed signs of endoscopic recurrence (apthae, ulcers, narrowing of the lumen) in the neoterminal ileum, five of whom also showed juxta-anastomotic colonic involvement. Fifteen patients were free of recurrence. At endoscopy, four biopsies were taken from the perianastomotic area (two specimens at the ileal site and two specimens at the colonic site of the anastomosis). The specimens were weighed and immediately frozen at -80 degrees C. Mesalazine concentration (ng/mg) was measured in tissue homogenates by high- performance liquid chromatography with electrochemical detection. Fisher's exact test was used for the statistical analysis. RESULTS: The mean value of mucosal mesalazine concentration, expressed as ng/mg of tissue, was significantly lower in patients with recurrence than in those without recurrence both in the ileum (mean +/- s.d.: 21.6+/-28.3 vs. 70.9+/-47.4; P = 0.007) and in the colon (25.8+/-26.4 vs. 60.3+/-32.5; P = 0.010). CONCLUSIONS: The mucosal concentration of mesalazine in the juxta-anastomatic area is significantly lower in patients with recurrence than in those free of recurrence. These data could suggest an association between mucosal mesalazine concentrations and the clinical effectiveness of the drug. (+info)