Salicylates for ulcerative colitis--their mode of action

Comprehensive overview of novel chemical drugs for ulcerative colitis: focusing on phase 3 and beyond

INTRODUCTION

Despite the growing number of highly efficacious biologics and chemical drugs for ulcerative colitis (UC), steroid-free disease control is still difficult to achieve in subgroups of patients due to refractoriness, adverse events, primary or secondary failure. New treatments are therefore still required in order to optimize clinical management of patients with UC.

AREAS COVERED

The efficacy and safety of both currently available and newly developed small molecules have been summarized. The PubMed database and clinicaltrials.gov were considered in order to search for phase 2b and 3 trials on new chemical drugs for UC. The study drugs reviewed included Janus kinases (JAK) and sphingosine-1-phosphate receptor (S1Pr) inhibitors, α4 integrin antagonist, and micro-RNA-124 upregulators.

EXPERT OPINION

Rapidity of onset, low immunogenicity, and safety are the main characteristics of small molecules currently available or under evaluation for treatment patients with UC. Among the currently available chemical drugs, the selective JAK and the S1Pr inhibitors are characterized by a good safety profile combined with the ability to induce clinical remission in UC. A relatively low frequency of endoscopic improvement and healing currently appears associated with their use, being higher in UC patients treated with S1Pr inhibitor Etrasimod. Overall, additional new safe and effective drugs are still required in order to optimize disease control in a larger majority of UC patients.

Peroxisome Proliferator-Activated Receptors: Experimental Targeting for the Treatment of Inflammatory Bowel Diseases

The peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor proteins that promote ligand-dependent transcription of target genes that regulate energy production, lipid metabolism, and inflammation. The PPAR superfamily comprises three subtypes, PPARα, PPARγ, and PPARβ/δ, with differential tissue distributions. In addition to their different roles in the regulation of energy balance and carbohydrate and lipid metabolism, an emerging function of PPARs includes normal homeostasis of intestinal tissue. PPARα activation represses NF-κB signaling, which decreases the inflammatory cytokine production by different cell types, while PPARγ ligands can inhibit activation of macrophages and the production of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and Il-1β. In this regard, the anti-inflammatory responses induced by PPAR activation might restore physiopathological imbalances associated with inflammatory bowel diseases (IBD). Thus, PPARs and their ligands have important therapeutic potential. This review briefly discusses the roles of PPARs in the physiopathology and therapies of the most important IBDs, ulcerative colitis (UC), and Crohn's disease (CD), as well some new experimental compounds with PPAR activity as promising drugs for IBD treatment.

Predicting and Understanding the Human Microbiome's Impact on Pharmacology

Our bodies each possess a unique and dynamic collection of microbes and viruses, collectively the 'microbiome', with distinct metabolic capacities from our human cells. Unforeseen modification of drugs by the microbiome can drastically alter their clinical effectiveness, with the most dramatic cases leading to fatal drug interactions. Pharmaceuticals can be activated, deactivated, toxified, or release metabolites that alter the 'canonical' pharmacokinetics of the drug. Thus, predicting and characterizing microbe-drug interactions is necessary to develop and implement personalized drug administration protocols and, more broadly, to improve drug safety and efficacy. In this review, we focus on microbiome-driven alterations to drug pharmacokinetics and provide a research framework for pharmacologists interested in characterizing microbiome interactions with any drug of interest.

Synthesis and in vitro Bioactivity Evaluation of New Galactose and Fructose Ester Derivatives of 5-Aminosalicylic Acid

Inflammatory bowel disease (IBD) is the main risk factor for developing colorectal cancer which is common in patients of all ages. 5-Aminosalicylic acid (5-ASA), structurally related to the salicylates, is highly active in the treatment of IBD with minor side effects. In this study, the synthesis of galactose and fructose esters of 5-ASA was planned to evaluate the role of glycoconjugation on the bioactivity of the parent drug. The antibacterial activity of the new compounds were evaluated against two Gram-negative and two Gram-positive species of bacteria, with a notable effect observed against Staphylococcus aureus and Escherichia coli in comparisons with the 5-ASA. Cytotoxicity testing over HT-29 and 3T3 cell lines indicated that the toxicity of the new products against normal cells was significantly reduced compared with the original drug, whereas their activity against cancerous cells was slightly decreased. The anti-inflammatory activity test in RAW264.7 macrophage cells indicated that the inhibition of nitric oxide by both of the monosaccharide conjugated derivatives was slightly improved in comparison with the non-conjugated drug.

N08C9 (Alliance): A Phase 3 Randomized Study of Sulfasalazine Versus Placebo in the Prevention of Acute Diarrhea in Patients Receiving Pelvic Radiation Therapy

PURPOSE

To provide confirmatory evidence on the use of sulfasalazine to reduce enteritis during pelvic radiation therapy (RT), following 2 prior single-institution trials suggestive that benefit existed.

METHODS AND MATERIALS

A multi-institution, randomized, double-blind, placebo-controlled phase 3 trial was designed to assess the efficacy of sulfasalazine versus placebo in the treatment of RT-related enteritis during RT including the posterior pelvis (45.0-53.5 Gy) and conducted through a multicenter national cooperative research alliance. Patients received 1000 mg of sulfasalazine or placebo orally twice daily during and for 4 weeks after RT. The primary endpoint was maximum severity of diarrhea (Common Terminology Criteria for Adverse Events version 4.0). Toxicity and bowel function were assessed by providers through a self-administered bowel function questionnaire taken weekly during RT and for 6 weeks afterward.

RESULTS

Eighty-seven patients were enrolled in the trial between April 29, 2011, and May 13, 2013, with evenly distributed baseline factors. At the time of a planned interim toxicity analysis, more patients with grade ≥3 diarrhea received sulfasalazine than received placebo (29% vs 11%, P=.04). A futility analysis showed that trial continuation would be unlikely to yield a positive result, and a research board recommended halting study treatment. Final analysis of the primary endpoint showed no significant difference in maximum diarrhea severity between the sulfasalazine and placebo arms (P=.41).

CONCLUSIONS

Sulfasalazine does not reduce enteritis during pelvic RT and may be associated with a higher risk of adverse events than placebo. This trial illustrates the importance of confirmatory phase 3 trials in the evaluation of symptom-control agents.

Sulfasalazine augments a pro-inflammatory response in interleukin-1β-stimulated amniocytes and myocytes

Preterm birth occurs in 10% of pregnancies and is a major cause of neonatal morbidity and mortality. The majority of cases of early preterm labour are associated with infection/inflammation, which places the fetal central nervous system at risk. Targeting immune activation is therefore an appealing therapeutic strategy for the prevention of preterm labour and neonatal brain injury. The expression of many labour-associated and inflammatory-response genes is controlled by the transcription factors nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), which makes them therapeutic targets of interest. Sulfasalazine (SASP) has been shown to inhibit NF-κB and reduce lipopolysaccharide-induced cytokine concentrations in fetal membrane explants and reduce the rate of Escherichia coli-induced preterm labour in mice. Its effects upon AP-1 in the context of pregnancy are unknown. In this study the effect of SASP on interleukin-1β (IL-1β) -induced NF-κB and AP-1 activity, cytokine production and cyclo-oxygenase-2 (COX-2) expression was examined in amniocytes and myocytes. A supra-therapeutic concentration (5 mm) was required to inhibit IL-1β-induced NF-κB (P < 0·0001) in amniocytes and IL-1β-induced NF-κB (P < 0·01), AP-1 (P < 0·01) and COX-2 (P < 0·05) in myocytes. Despite inhibiting IL-1β-induced cytokines, a basal increase in IL-6 (P < 0·01), IL-8 (P < 0·0001) and tumour necrosis factor-α (TNF-α) (P < 0·001) was seen with 5 mm SASP in amniocytes, and significant cytotoxic effects were seen in myocytes. The therapeutic concentration of 0·015 mm had no inhibitory effects on pro-inflammatory mediators, but led to an augmented response to IL-1β-induced IL-6 (P < 0·01), IL-8 (P < 0·05) and TNF-α (P < 0·05) in amniocytes and IL-8 (P < 0·05) in myocytes. SASP is therefore an unlikely therapeutic candidate for the prevention of inflammation-induced preterm labour.

Synthesis and in vitro bioactivity evaluation of new glucose and xylitol ester derivatives of 5-aminosalicylic acid

Synthesis,in vitroanti-bacterial, anti-inflammatory and anti-cancer activity evaluations andin silicostudy of monosaccharide derivatives of mesalazine in comparison with parent drug.

Distinct kinetics in the frequency of peripheral CD4+ T cells in patients with ulcerative colitis experiencing a flare during treatment with mesalazine or with a herbal preparation of myrrh, chamomile, and coffee charcoal

BACKGROUND

We found the first evidence of the efficacy of a herbal treatment with myrrh, dry extract of chamomile flowers, and coffee charcoal for ulcerative colitis (UC). However, the impact of the herbal treatment on the CD4+ T-cell compartment, which is essential for both the induction of UC and the maintenance of tolerance in the gut, is not well understood.

AIM

To analyze the frequency and functional phenotype of CD4+ T cells and of immune-suppressive CD4+CD25high regulatory T cells (Tregs) in healthy control subjects, patients with UC in remission, and patients with clinical flare of UC.

METHODS

Patients in clinical remission were treated with either mesalazine or the herbal preparation for 12 months. The frequencies of whole CD4+ T cells, CD4+CD25med effector T cells, and Tregs and the expression of Foxp3 within the CD4+CD25hig Tregs were determined by flow cytometry at 6 time points. We determined the suppressive capability of Tregs from healthy control subjects and from patients in remission or clinical flare.

RESULTS

A total of 79 patients (42 women, 37 men; mean age, 48.5 years; 38 with clinical flare) and 5 healthy control subjects were included in the study. At baseline the frequencies of whole CD4+ T cells, CD4+CD25med effector cells, and Tregs did not differ between the two treatment groups and the healthy control subjects. In addition, patients with UC in sustained clinical remission showed no alteration from baseline after 1, 3, 6, 9, or 12 months of either treatment. In contrast, CD4+ T cells, CD4+CD25med effector T cells, and Tregs demonstrated distinctly different patterns at time points pre-flare and flare. The mesalazine group showed a continuous but not statistically significant increase from baseline to pre-flare and flare (p = ns). In the herbal treatment group, however, the percentage of the CD4+ T cells was lower at pre-flare than at baseline. This decrease was completely reversed after flare, when a significant increase was seen (CD4+CD25med pre-flare/flare p = 0.0461; CD4+CD25high baseline/flare p = 0.0269 and pre-flare/flare p = 0.0032). In contrast, no changes in the expression of Foxp3 cells were detected within the subsets of CD4+CD25high regulatory T cells. Of note, no alterations were detected in the suppressive capability of CD4+CD25high regulatory T cells isolated from the peripheral blood of healthy donors, from patients in remission, or from patients with clinical flare.

CONCLUSIONS

In patients with UC experiencing acute flare, the CD4+ T compartment demonstrates a distinctly different pattern during treatment with myrrh, chamomile extract, and coffee charcoal than during treatment with mesalazine. These findings suggest an active repopulation of regulatory T cells during active disease.

TRIAL REGISTRATION

EU Clinical Trials Register 2007-007928-18/DE.

Dietary arachidonic and oleic acid intake in ulcerative colitis etiology: a prospective cohort study using 7-day food diaries

INTRODUCTION

Dietary fatty acids may be involved in the etiology of ulcerative colitis (UC). Arachidonic acid (AA), an n-6 polyunsaturated fatty acid, is a precursor of the proinflammatory cytokines prostaglandin E2 and leukotriene B4, and its metabolism is competitively inhibited by oleic acid (OA). This study aimed to prospectively investigate whether AA is positively and OA is negatively associated with incident UC development, using data from 7-day food diaries.

METHODS

A total of 25 639 men and women, aged between 40 and 79 years, from Norfolk, UK, were recruited into the prospective European Prospective Investigation into Cancer (EPIC)-Norfolk cohort between 1993 and 1997. At baseline, participants completed 7-day food diaries, checked by nutritionists using a database containing 11 000 foods and 55 000 portion sizes. The cohort was monitored until June 2004 to identify participants who developed UC. Each patient was matched for age and sex with four controls, and conditional logistic regression was used to calculate adjusted odds ratios for AA and OA intakes, and UC association.

RESULTS

Of the participants, 26 (58% men) developed incident UC (53% left sided) after a median follow-up time of 3.8 years (0.5-8.3 years). The highest AA tertile was positively associated with an odds ratio of 6.09 [95% confidence interval (CI) 1.05-35.23], with a trend across tertiles [odds ratio (OR) 2.43, 95% CI 1.06-5.61, P=0.04]. The highest tertile of OA intake was inversely associated with a 0.03 OR for UC (95% CI 0.002-0.56) and an inverse trend (OR 0.30, 95% CI 0.10-0.90, P=0.03).

CONCLUSION

Dietary AA was positively and OA was inversely associated with UC development, with large effect sizes in a dose-dependent manner. This supports roles for measuring these nutrients in future etiological studies and modifying intake in future interventional studies in patients with established disease.

Development and characterization of sulfasalazine loaded fucosylated PPI dendrimer for the treatment of cytokine-induced liver damage

The present investigation was aimed at exploring the targeting potential of sulfasalazine (NF-κB inhibitor drug) loaded fucose tethered poly (propylene imine) (PPI) dendritic nanoarchitecture (SSZ-FUCO-PPID) to Kupffer cells for effective management of cytokine-induced liver damage. The SSZ-FUCO-PPID formulation was characterized for entrapment efficiency, in vitro release, stability, toxicological investigations, macrophage uptake, NF-κB inhibition, and in vivo studies. In cell uptake assay the uptake of SSZ-FUCO-PPID was found to be higher and preferentially by J774 macrophage cell line. Cytokine assay suggested that the SSZ-FUCO-PPID potentially inhibited the IL-12 p40 production in LPS activated macrophages. Western blot analysis clearly suggested that SSZ-FUCO-PPID inhibited the activation of NF-κB as indicated by the absence of p-IκB band. Pharmacokinetic study revealed improved bioavailability, half-life and mean residence time of SSZ upon fucosylation of dendrimers. The biodistribution pattern clearly established the higher amount of SSZ-FUCO-PPID in liver. Hematological data suggest that the fucosylated formulations are less immunogenic as compared to unconjugated formulations. The results suggest that the SSZ-FUCO-PPID formulation holds targeting potential to Kupffer cells for the treatment of cytokine-induced liver damage.

Fucosylated multiwalled carbon nanotubes for Kupffer cells targeting for the treatment of cytokine-induced liver damage

PURPOSE

To develop, characterize and exploring the sulfasalazine loaded fucoyslated multi walled carbon nanotubes for Kupffer cell targeting for effective management of cytokine-induce liver damage.

METHODS

Sulfasalazine was loaded into the fucosylated MWCNTs after subsequential functionalization (carboxylation, acylation and amidation) using dialysis membrane technique. The in vitro, in vivo studies were performed on macrophages J 774 cell line for Kupffer cells targeting for the treatment of cytokine-induced liver damage.

RESULTS

The loading of SSZ into SSZ-FUCO-MWCNTs was 87.77 ± 0.11% (n = 3). Sustained release was obtained from SSZ-FUCO-MWCNTs, with 89.12 ± 0.71% of SSZ released into medium at 48th hr. SSZ-FUCO-MWCNTs showed the 9.0  ± 0.23% hemolysis was drastically reduced from 21.62 ± 0.24% SSZMWCNTs 21.62 ± 0.24%. In SRB assay, SSZ-FUCO-MWCNTs showed more cytotoxicity than raw and SSZ-MWCNTs. In cytokine assay, SSZ- FUCO-MWCNTs exhibited significantly higher inhibition of IL-12 p40 secretion. In Western blot assay, SSZ-FUCO-MWCNTs significantly inhibit NF-κB activation.

CONCLUSION

The results suggested that the SSZ-FUCO-MWCNTs may be useful nano-carriers for targeted delivery to Kupffer cells in the treatment of cytokine-induced liver damage.

Ulcerative colitis impairs the acylethanolamide-based anti-inflammatory system reversal by 5-aminosalicylic acid and glucocorticoids

Studies in animal models and humans suggest anti-inflammatory roles on the N-acylethanolamide (NAE)-peroxisome proliferators activated receptor alpha (PPARα) system in inflammatory bowel diseases. However, the presence and function of NAE-PPARα signaling system in the ulcerative colitis (UC) of humans remain unknown as well as its response to active anti-inflammatory therapies such as 5-aminosalicylic acid (5-ASA) and glucocorticoids. Expression of PPARα receptor and PPARα ligands-biosynthetic (NAPE-PLD) and -degrading (FAAH and NAAA) enzymes were analyzed in untreated active and 5-ASA/glucocorticoids/immunomodulators-treated quiescent UC patients compared to healthy human colonic tissue by RT-PCR and immunohistochemical analyses. PPARα, NAAA, NAPE-PLD and FAAH showed differential distributions in the colonic epithelium, lamina propria, smooth muscle and enteric plexus. Gene expression analysis indicated a decrease of PPARα, PPARγ and NAAA, and an increase of FAAH and iNOS in the active colitis mucosa. Immunohistochemical expression in active colitis epithelium confirmed a PPARα decrease, but showed a sharp NAAA increase and a NAPE-PLD decrease, which were partially restored to control levels after treatment. We also characterized the immune cells of the UC mucosa infiltrate. We detected a decreased number of NAAA-positive and an increased number of FAAH-positive immune cells in active UC, which were partially restored to control levels after treatment. NAE-PPARα signaling system is impaired during active UC and 5-ASA/glucocorticoids treatment restored its normal expression. Since 5-ASA actions may work through PPARα and glucocorticoids through NAE-producing/degrading enzymes, the use of PPARα agonists or FAAH/NAAA blockers that increases endogenous PPARα ligands may yield similar therapeutics advantages.

Intestinal Anti-Inflammatory Activity of Baccharis dracunculifolia in the Trinitrobenzenesulphonic Acid Model of Rat Colitis

Baccharis dracunculifolia DC (Asteraceae) is a Brazilian medicinal plant popularly used for its antiulcer and anti-inflammatory properties. This plant is the main botanical source of Brazilian green propolis, a natural product incorporated into food and beverages to improve health. The present study aimed to investigate the chemical profile and intestinal anti-inflammatory activity of B. dracunculifolia extract on experimental ulcerative colitis induced by trinitrobenzenosulfonic acid (TNBS). Colonic damage was evaluated macroscopically and biochemically through its evaluation of glutathione content and its myeloperoxidase (MPO) and alkaline phosphatase activities. Additional in vitro experiments were performed in order to test the antioxidant activity by inhibition of induced lipid peroxidation in the rat brain membrane. Phytochemical analysis was performed by HPLC using authentic standards. The administration of plant extract (5 and 50 mg kg⁻¹) significantly attenuated the colonic damage induced by TNBS as evidenced both macroscopically and biochemically. This beneficial effect can be associated with an improvement in the colonic oxidative status, since plant extract prevented glutathione depletion, inhibited lipid peroxidation and reduced MPO activity. Caffeic acid, p-coumaric acid, aromadendrin-4-O-methyl ether, 3-prenyl-p-coumaric acid, 3,5-diprenyl-p-coumaric acid and baccharin were detected in the plant extract.

An association between dietary arachidonic acid, measured in adipose tissue, and ulcerative colitis

BACKGROUND & AIMS

Dietary arachidonic acid, an n-6 polyunsaturated fatty acid (n-6 PUFA), might be involved in the etiology of ulcerative colitis (UC). We performed a prospective cohort study to determine whether high levels of arachidonic acid in adipose tissue samples (which reflects dietary intake) are associated with UC.

METHODS

We analyzed data collected from 57,053 men and women in the EPIC-Denmark Prospective Cohort Study from 1993 to 1997. Adipose tissue biopsy samples were collected from gluteal regions at the beginning of the study, the cohort was monitored over subsequent years, and participants who developed UC were identified. A subcohort of 2510 randomly selected participants were used as controls. Concentrations of arachidonic acid were measured in adipose tissue samples. In the analysis, arachidonic acid levels were divided into quartiles; relative risks (RR) were calculated and adjusted for smoking, use of aspirin and nonsteroidal anti-inflammatory drugs, and levels of n-3 PUFAs.

RESULTS

A total of 34 subjects (56% men) developed incident UC at a median age of 58.8 years (range, 50.0-69.0 years). Those in the highest quartile for arachidonic acid concentrations in adipose tissue had an RR for UC of 4.16 (95% confidence interval [CI]: 1.56-11.04); a trend per 0.1% increase in arachidonic acid of 1.77 in RR was observed (95% CI: 1.38-2.27). The fraction attributed the highest levels of arachidonic acid was 40.3%.

CONCLUSIONS

Individuals with the highest relative concentrations of arachidonic acid in adipose tissue have a significantly greater risk of developing UC. Dietary modifications might therefore prevent UC or reduce disease symptoms.

A meta-analysis of the efficacy of sulfasalazine in comparison with 5-aminosalicylates in the induction of improvement and maintenance of remission in patients with ulcerative colitis

BACKGROUND

Historically, sulfasalazine (SSZ) and 5-aminosalicylates (5-ASAs) have been a mainstay of mild-to-moderate ulcerative colitis (UC) remission induction and maintenance therapy. Considering the pivotal role of intestinal microbial flora in pathophysiology of UC and antimicrobial activity of sulfapyridine, we hypothesized that SSZ might be more effective than 5-ASAs in the management of UC.

AIM

To compare the efficacy and tolerability of SSZ with each of the 5-ASAs (mesalamine, olsalazine, and balsalazide) by a meta-analysis technique.

METHODS

Pubmed, Embase, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials were searched for studies compared efficacy and/or tolerability of SSZ with 5-ASAs in the management of UC. The search terms were: "sulfasalazine" or "sulfasalazine" and "5-aminosalicylic acid," "mesalazine," "mesalamine," "olsalazine" or "balsalazide" and "ulcerative colitis." Data were collected from 1966 to April 2008. There was no language restriction. "Overall improvement," "relapse rate," "total adverse events," and "withdrawals because of adverse events" were the key outcomes of interest.

RESULTS

Twenty randomized placebo controlled trials met our criteria and were included in the meta-analysis. Comparison of SSZ with mesalamine yielded a nonsignificant relative risk (RR) of 1.04 (95% confidence interval of 0.89-1.21, P = 0.63) for overall improvement, a nonsignificant RR of 0.98 (95% CI 0.78-1.23, P = 0.85) for relapse, a nonsignificant RR of 0.76 (95% CI 0.54-1.07, P = 0.11) for any adverse events, and a nonsignificant RR of 0.78 (95% CI 0.46-1.3, P = 0.33) for withdrawals due to adverse events. Comparison of SSZ with olsalazine yielded a nonsignificant RR of 1.14 (95% CI 0.91-1.43, P = 0.25) for overall improvement, a nonsignificant RR of 0.93 (95% CI 0.77-1.12, P = 0.42) for relapse, a nonsignificant RR of 1.21 (95% CI 0.9-1.61, P = 0.20) for any adverse events, and a nonsignificant RR of 1.53 (95% CI 0.93-2.52, P = 0.09) for withdrawals due to adverse events. Comparison of SSZ with balsalazide yielded a nonsignificant RR of 1.3 (95% CI 0.93-1.81, P = 0.12) for overall improvement, and a significant RR of 0.17 (95% CI 0.06-0.49, P = 0.001) for withdrawals because of adverse events.

CONCLUSION

SSZ does not differ from mesalamine or olsalazine in terms of efficacy and tolerability in UC. Withdrawal from study due to adverse events was significantly lower for balsalazide compared with SSZ. Convincing conclusions on the comparison of effectiveness and safety of balsalazide and SSZ in UC remains to be elucidated by further clinical trials. Considering the lower cost of treatment with SSZ and the equal rate of adverse events with other 5-ASAa, it is not surprising to suggest SSZ as a first-choice treatment for UC and reserve 5-ASAs for when SSZ intolerability occurs.

Comparison of mesalazine and balsalazide in induction and maintenance of remission in patients with ulcerative colitis: a meta-analysis

BACKGROUND

5-Aminosalicylates are the standard treatment for induction and maintenance of remission in mild-to-moderate ulcerative colitis. In recent years, the 5-aminosalicylic acid-containing pro-drug balsalazide has been the focus of attention.

AIM

To compare the efficacy and tolerance of balsalazide and mesalazine by meta-analysis.

METHODS

Pubmed, Embase, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for studies comparing the efficacy and/or tolerance of balsalazide with mesalazine in the management of UC. The search terms were: "mesalazine" or "5-aminosalicylic acid" and "balsalazide" and "ulcerative colitis." Data were collected from 1966 to 2007 (up to February). There was no language restriction. "Symptomatic remission," "complete remission," "relapse rate," "total adverse events," and "withdrawals because of adverse events" were the key outcomes of interest.

RESULTS

Six randomized placebo-controlled clinical trials met our criteria and were included in the meta-analysis. In these "symptomatic remission," "complete remission," "relapse rate," "total adverse events," and "withdrawals because of adverse events" were evaluated in three, three, two, five, and six of the trials, respectively. They included 653 patients consisting of 55.4% men and 44.6% women randomized to receive either balsalazide or mesalazine. Pooling of three trials for symptomatic remission yielded a significant relative risk (RR) of 1.23 (95% confidence interval of 1.03-1.47, P = 0.02). The summary RR for complete remission in three trials was 1.3 (95% CI of 1.002-1.68, P = 0.048). Pooling of two trials for the outcome of relapse yielded a non-significant RR of 0.77 (95% CI of 0.56-1.07, P = 0.12). Pooling five studies from which data for any adverse events were extracted, yielded a non-significant RR of 0.87 (95% CI of 0.75-1.001, P = 0.53). The summary RR for withdrawals because of adverse events in six trials was 0.69, a non-significant RR (95% CI of 0.37-1.29, P = 0.24).

CONCLUSION

Balsalazide is more effective than mesalazine in induction of remission, but balsalazide has no benefit compared with mesalazine in preventing relapse in the population selected. The number of patients with any adverse events and withdrawals because of severe adverse events is similar for mesalazine and balsalazide.

A comparative study of the preventative effects exerted by three probiotics, Bifidobacterium lactis, Lactobacillus casei and Lactobacillus acidophilus, in the TNBS model of rat colitis

AIMS

The intestinal anti-inflammatory effects of three probiotics with immunomodulatory properties, Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium lactis, were evaluated and compared in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis.

METHODS AND RESULTS

Colitis was induced in rats by intracolonic administration of 10 mg of TNBS dissolved in 0.25 ml of 50% ethanol. Each probiotic was administered orally (5x10(8) CFU suspended in 0.5 ml of skimmed milk) for 3 weeks, starting 2 weeks before the administration of TNBS. Colonic damage was evaluated histologically and biochemically 1 week after TNBS instillation. The results obtained revealed that all probiotics assayed showed intestinal anti-inflammatory effects, macroscopically evidenced by a significant reduction in the colonic weight/length ratio. Only B. lactis showed a lower incidence of diarrhoea in comparison with untreated rats. Biochemically, all probiotics restored colonic glutathione levels, depleted as a consequence of the oxidative stress of the inflammatory process. Bifidobacterium lactis treatment reduced colonic tumour necrosis factor (TNF)-alpha production, and inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) expression; L. acidophilus administration reduced colonic leukotriene B4 production and iNOS expression and L. casei intake was associated with a decrease in colonic COX-2 expression.

CONCLUSION

The three probiotics assayed have shown intestinal anti-inflammatory activity in the TNBS model of rat colitis, although each probiotic shows its own anti-inflammatory profile.

SIGNIFICANCE AND IMPACT OF THE STUDY

These probiotics could be considered as potential adjuvants in the treatment of inflammatory bowel disease, although more studies are required in order to demonstrate their efficacy in humans.

Lactobacillus fermentum, a probiotic capable to release glutathione, prevents colonic inflammation in the TNBS model of rat colitis

BACKGROUND AND AIMS

Inflammatory bowel disease is associated with intestinal oxidative stress. In the present study we test the preventative effect of Lactobacillus fermentum, a probiotic that produces per se glutathione, in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis.

METHODS

Colitis was induced in rats by intracolonic administration of 10 mg of TNBS dissolved in 0.25 ml of 50% ethanol. L. fermentum was administered orally (5x10(8) CFU suspended in 0.5 ml of skim milk) to a group of rats for 3 weeks, starting 2 weeks before colitis induction. Colonic damage was evaluated both histologically and biochemically, and the colonic luminal contents were used for bacterial studies as well as for short chain fatty acid (SCFA) production.

RESULTS

L. fermentum treatment resulted in an amelioration of the inflammatory response in colitic rats as evidenced histologically and by a significant reduction of colonic MPO activity (P<0.05). The probiotic partially counteracted the colonic glutathione depletion induced by the inflammatory process. In addition, probiotic-treated colitic rats showed significant lower colonic tumour necrosis factor (TNF)alpha levels (P<0.01) and inducible nitric oxide synthase (iNOS) expression when compared to non-treated rats. Finally, the probiotic induced growth of Lactobacilli species and production of SCFA in colonic contents in comparison with control colitic rats.

CONCLUSION

Administration of the probiotic L. fermentum facilitates the recovery of the inflamed tissue in the TNBS model of rat colitis, an effect associated with increased levels of glutathione as well as with amelioration of the production of some of the mediators involved in the inflammatory response of the intestine, such as TNFalpha and NO.

Intestinal anti-inflammatory activity of combined quercitrin and dietary olive oil supplemented with fish oil, rich in EPA and DHA (n-3) polyunsaturated fatty acids, in rats with DSS-induced colitis

BACKGROUND AND AIMS

Previous studies have described the intestinal anti-inflammatory effects exerted by the bioflavonoid quercitrin (QR) and by an n-3 polyunsaturated fatty acids (PUFA)-enriched diet in experimental models of rat colitis. The aim of the present study was to test if the combination of both treatments would result in an improvement in the intestinal anti-inflammatory effect achieved separately.

METHODS

Colitis was induced in female Wistar rats by incorporating dextran sodium sulfate (DSS) in drinking water at 5% (w/v) for 5 days and at 2% (w/v) for the following 10 days. Five groups of rats (n=10) were used: two of them received an olive-oil-based diet with fish oil, rich in n-3 PUFA (FO diet) for 2 weeks before colitis induction and until the end of the experiment, and one of those also was administered daily QR (1mg/kg, PO), starting when DSS concentration was changed. DSS colitis was induced in other two groups fed with standard rat diet, one of them being administered QR as before. A non-colitic group fed standard diet was also included. After that period, the rats were sacrificed and colonic damage was assessed both histologically and biochemically.

RESULTS

The concurrent administration of FO diet and QR exhibited an intestinal anti-inflammatory effect, as evidenced by a significant improvement of all biochemical parameters of colonic inflammation assayed in comparison with non-treated colitic rats. Thus, both colonic myeloperoxidase (MPO) and alkaline phosphatase (AP) activities were significantly reduced compared with untreated colitic rats. In addition, a complete restoration of colonic glutathione content, which was depleted as a consequence of the colonic insult, was obtained in rats treated with QR plus FO diet; this content was even higher than that obtained when colitic rats were treated with FO diet alone. When compared with the control colitic group, the combined treatment was also associated with a lower colonic nitric oxide synthase and cyclooxygenase-2 expression as well as with a significant reduction in different colonic proinflammatory mediators assayed, i.e. leukotriene B(4), tumor necrosis factor alpha and interleukin 1beta, showing a significantly greater inhibitory effect of the latter in comparison with rats receiving FO diet without the flavonoid.

CONCLUSIONS

These results support the potential synergism between the administration of the flavonoid and the incorporation of olive oil and n-3 PUFA to the diet for the treatment of these intestinal inflammatory disorders.

How important is onset of action in ulcerative colitis therapy?

Pharmacotherapy is the cornerstone of management in ulcerative colitis. However, controversy remains over optimal medical strategies. Specifically, differences in the onset of action of various drug therapies are thought to influence the achievement and maintenance of remission of disease, yet this is poorly characterised. There is a wide range of recent data concerning aminosalicylates, with much debate as to the relative merits of the various formulations and delivery systems. Meta-analyses confirm the efficacy of aminosalicylates for the induction and maintenance of remission and suggest that the newer agents are comparable in efficacy to sulfasalazine. Among aminosalicylates, data from clinical trials reveal that the onset of action is earlier with balsalazide than mesalazine. Although the efficacy of the newer 5-aminosalicylate agents is no greater than that of sulfasalazine, they have better adverse effect profiles. Factors such as tolerability and adherence appear more important than onset of action in long-term maintenance. Corticosteroids have long been used in the treatment of ulcerative colitis, yet there is a paucity of data regarding this. They have a rapid onset of action but considerable systemic adverse effects. Therefore, corticosteroids are reserved for disease that fails to respond to other agents or for primary therapy in patients with severe disease, although there is no universal acceptance of a threshold at which to initiate corticosteroid treatment.Rectal preparations of both aminosalicylates and corticosteroids have been developed in an attempt to exert a more rapid and direct onset of action while minimising adverse systemic effects. In clinical trials, topical preparations of both aminosalicylates and corticosteroids are effective in inducing remission. However, patient acceptability and proximal extent of disease dictate selection of a topical agent more than concern with rate of onset.A wide range of immunomodulators have been investigated in patients with steroid-refractory ulcerative colitis. The thioguanine derivatives are the most widely used but have a limited evidence base to support this use with controlled trials providing equivocal results regarding efficacy in severe ulcerative colitis. In addition, the thioguanine derivatives have a protracted onset of action and a considerable serious adverse effect profile. Calcineurin inhibitors and methotrexate have a more rapid onset of action than the thiopurines but have even less data to support their widespread use. They are widely regarded as salvage therapy and further data are required. Regarding biological agents, infliximab revolutionised the treatment of Crohn's disease, yet results in ulcerative colitis have been disappointing. Further trials are ongoing with great anticipation for more favourable data. The practical clinical implications of any differences between the agents depend on patient satisfaction with various therapies. Noncompliance is a major concern in maintenance therapy and is probably associated with relapse. Dose administration schedules and acceptability of therapy appear to be important factors in adherence. Overall, it is not clear that onset of action has a major influence on patient adherence and addressing issues of compliance may have more direct clinical impact.

Dietary olive oil supplemented with fish oil, rich in EPA and DHA (n-3) polyunsaturated fatty acids, attenuates colonic inflammation in rats with DSS-induced colitis

Previous studies proposed a protective role of the dietary intake of (n-3) PUFA in human inflammatory bowel disease (IBD), but almost no studies have been performed using olive oil. The aims of the present study were to test the beneficial effects of an olive oil-based diet with or without fish oil, rich in (n-3) PUFA, in the dextran sodium sulfate (DSS) model of rat colitis and to elucidate the mechanisms involved in their potential beneficial effects, with special attention to the production of some of the mediators involved in the intestinal inflammatory response, such as leukotriene B(4) (LTB(4)), tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO). Rats were fed the different diets for 2 wk before colitis induction and thereafter until colonic evaluation 15 d later. Colitic rats fed the olive oil-based diet had a lower colonic inflammatory response than those fed the soybean oil diet, and this beneficial effect was increased by the dietary incorporation of (n-3) PUFA. A restoration of colonic glutathione levels and lower colonic NO synthase expression occurred in all colitic rats fed an olive oil diet compared with the control colitic group that consumed the soybean oil diet. However, (n-3) PUFA incorporation into an olive oil diet significantly decreased colonic TNFalpha and LTB(4) levels compared with colitic rats that were not supplemented with fish oil. These results affirm the benefits of an olive oil diet in the management of IBD, which are further enhanced by the addition of (n-3) PUFA.

The intestinal anti-inflammatory effect of quercitrin is associated with an inhibition in iNOS expression

Quercitrin, 3-rhamnosylquercetin, is a bioflavonoid with antioxidant properties, which exerts anti-inflammatory activity in experimental colitis. In the present study, different in vivo experiments were performed in order to evaluate the mechanisms of action involved in this effect, with special attention to its effects on proinflammatory mediators, including nitric oxide (NO). Experimental colitis was induced in female Wistar rats by incorporation of dextran sodium sulfate (DSS) in drinking water. Oral treatment of quercitrin (1 or 5 mg kg(-1) day(-1)) to colitic rats ameliorated the evolution of the inflammatory process induced when administered in a preventative dosing protocol. When quercitrin (1 mg kg(-1) day(-1)) was administered on established colitis, it facilitated the recovery of the inflamed mucosa. The beneficial effects exerted by quercitrin were evidenced both histologically and biochemically, and were associated with an improvement in the colonic oxidative status, altered as a consequence of the colonic insult induced by DSS. In addition, a reduction of colonic NO synthase activity was observed, probably related to a decreased expression in the inducible form of the enzyme via downregulation in the colonic activity of the nuclear factor-kappaB. Immunohistochemical studies showed that quercitrin treatment reduced macrophage and granulocyte infiltration in the inflamed tissue.

The intestinal anti-inflammatory activity of UR-12746S on reactivated experimental colitis is mediated through downregulation of cytokine production

BACKGROUND

UR-12746S (dersalazine sodium) is cleaved by colonic bacteria delivering the PAF antagonist UR-12715 and 5-ASA. This study describes the anti-inflammatory activity of UR-12746S in an experimental model of reactivated colitis and its effects on cytokine production.

METHODS

Rats were initially rendered colitic by a colonic instillation of 10 mg of trinitrobenzenesulphonic acid (TNBS) dissolved in 0.25 ml of 50 % ethanol, and colitis was reactivated two weeks after by a second administration of the same dose of TNBS. Two groups of colitic rats received UR-12746S (25 and 50 mg/kg daily, p.o.) and colonic damage was evaluated every week for 4 weeks. Different biochemical markers of colonic inflammation were assayed: MPO activity and cytokine (IL-1beta and TNFalpha) levels. Also, the in vitro effects of UR-12715 and 5-ASA on cytokine production were assayed.

RESULTS

UR-12746S showed anti-inflammatory effect in reactivated colitis in rats, as evidenced by a significant reduction in MPO activity. Both doses of UR-12746S decreased IL-1beta production, while only the highest dose assayed inhibited TNFalpha production. In vitro studies revealed that UR-12715 or 5-ASA (from 10(-6) to 10(-4) M) inhibited IL-8 production (30-40%) in HT-29 cells when incubated with LPS. This inhibitory effect was enhanced when both compounds were administered simultaneously at 10(-4) M. In addition, UR-12715 inhibited IL-1beta or TNFalpha production in THP-1 or U937 cells, respectively, when these cells were stimulated by PMA and LPS; whereas 5-ASA only showed a weak effect in inhibiting IL-1beta production.

CONCLUSION

UR-12746S was able to prevent relapse in experimental colitis and inhibition of proinflammatory cytokine production participates in the intestinal anti-inflammatory activity exerted by this compound.

NF-kappaB-independent actions of sulfasalazine dissociate the CD95L- and Apo2L/TRAIL-dependent death signaling pathways in human malignant glioma cells

Death receptor-mediated apoptosis of human malignant glioma cells triggered by CD95 ligand (CD95L) or Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) share several features, including processing of multiple caspases and mitochondrial cytochrome c release. We here report that CD95L-induced cell death is inhibited by sulfasalazine (SS) in all of four human glioma cell lines, both in the absence and presence of cycloheximide (CHX). Coexposure to CD95L and SS prevents the CD95L-evoked processing of caspases 2, 3, 8 and 9, the release of cytochrome c from mitochondria, and the loss of BCL-x(L) protein. This places the protective effect of SS proximal to most known events triggered by the CD95-dependent signaling pathway in glioma cells. CD95L promotes the accumulation of nuclear factor kappa B (NF-kappaB) in the nucleus and induces the DNA-binding activity of NF-kappaB assessed by electrophoretic mobility shift assay. The total levels of p50, p65 and IkappaBalpha remain unchanged, but the levels of phosphorylated IkappaBalpha and of nuclear p65 increase, in response to CD95L. IkappaBalpha phosphorylation as well as nuclear NF-kappaB translocation and DNA binding are blocked by SS. However, unlike SS, dominant-negative IkappaBalpha (IkappaBdn) does not block apoptosis, suggesting that SS inhibits CD95L-mediated apoptosis in an NF-kappaB-independent manner. In contrast to CD95L, the cytotoxic effects of Apo2L/TRAIL are enhanced by SS, and SS facilitates Apo2L/TRAIL-evoked caspase processing, cytochrome c release, and nuclear translocation of p65. These effects of SS are nullified in the presence of CHX, suggesting that the effects of SS and CHX are redundant or that enhanced apoptosis mediated by SS requires protein synthesis. IkappaBdn fails to modulate Apo2L/TRAIL-induced apoptosis. Similar effects of SS on CD95L- and Apo2L/TRAIL-induced apoptosis are observed in MCF-7 breast and HCT116 colon carcinoma cells. Interestingly, HCT cells lacking p21 (80S14(p21-/-)) are only slightly protected by SS from CD95L-induced apoptosis, but sensitized to Apo2L/TRAIL-induced apoptosis, indicating a link between the actions of SS and p21. Thus, SS modulates the death cascades triggered by CD95L and Apo2L/TRAIL in opposite directions in an NF-kappaB-independent manner, and SS may be a promising agent for the augmentation of Apo2L/TRAIL-based cancer therapies.

Balsalazide: a review of its therapeutic use in mild-to-moderate ulcerative colitis

The aminosalicylate balsalazide is a prodrug which is metabolised by bacterial azo reductases in the colon to release its therapeutically active moiety mesalazine [mesalamine (US) or 5-aminosalicylic acid] and an inert carrier molecule. The systemic absorption of balsalazide and its metabolites is not required for the therapeutic efficacy of the drug, and has been demonstrated to be limited. Data from well designed trials with a duration of 8 to 12 weeks show that oral balsalazide 6.75 g/day is as effective as (two trials) or more effective than (one trial) oral delayed-release (pH-dependent) mesalazine 2.4 g/day and appears to be as effective as oral sulfasalazine 3 g/day in the treatment of active mild-to-moderate ulcerative colitis. In addition, balsalazide appears to have a faster onset of action than mesalazine. Furthermore, balsalazide was as effective as delayed-release mesalazine (dosages used were 1.2 and 1.5 g/day, where 1.6 g/day is recommended) and oral sulfasalazine 2 g/day (recommended dosage) in the prevention of relapse in ulcerative colitis in remission after 6 to 12 months of treatment; the balsalazide dosage was 3 g/day versus mesalazine and 2 g/day versus sulfasalazine. Although not well established, additional benefits may be achieved with balsalazide dosages up to 6 g/day. Data from well designed, 2- to 12-month trials show that balsalazide is well tolerated by patients with ulcerative colitis in both acute and maintenance indications, and is better tolerated than standard formulations of sulfasalazine at therapeutically relevant dosages.

CONCLUSION

Balsalazide is a well tolerated and effective first-line therapeutic option for patients with ulcerative colitis, both for the treatment of active mild-to-moderate disease and as maintenance therapy to prevent disease relapse.

Nuclear factor kappa B regulation of proinflammatory cytokines in human gestational tissues in vitro

Proinflammatory cytokines are implicated in the initiation and progression of human labor and delivery, particularly in relation to infection-induced preterm labor. In nongestational tissues, the nuclear factor kappa B (NF-kappaB) transcription pathway is a key regulator of proinflammatory cytokine release. In these tissues, sulfasalazine (SASP), through its ability to inhibit NF-kappaB activation, inhibits release of interleukin (IL)-2, IL-12, and tumor necrosis factor (TNF)-alpha. Therefore, the aim of this study was to investigate whether or not NF-kappaB activation regulates the formation of proinflammatory cytokines in human gestational tissues. Human placenta, amnion, and choriodecidua (n = 9 separate placentas) were incubated with 10 microg/ml of lipopolysaccharide (LPS) in the absence (control) or presence of SASP (0.1, 1, 5, or 10 mM). After 6 h of incubation, the tissues were collected, and NF-kappaB DNA binding activity in nuclear extracts was assessed by electromobility shift binding assay. The incubation medium was collected and the release of IL-6, IL-8, and TNF-alpha was quantified by ELISA. Treatment of placenta, amnion, and choriodecidua with SASP at concentrations 5 mM or greater significantly inhibited the release of IL-6, IL-8, and TNF-alpha, and NF-kappaB activation (ANOVA, P < 0.05). The data presented in this study demonstrate that the NF-kappaB transcription pathway is a key regulator of LPS-stimulated IL-6, IL-8, and TNF-alpha release from human gestational tissues. The control of NF-kappaB activation may therefore provide an alternative therapeutic strategy for reducing the release of proinflammatory mediators in infection associated preterm labor.

Intestinal anti-inflammatory activity of morin on chronic experimental colitis in the rat

BACKGROUND

Morin, a bioflavonoid with antioxidant properties, shows intestinal anti-inflammatory activity in the acute phase of the trinitrobenzenesulphonic acid model of rat colitis.

AIM

To assess the anti-inflammatory activity of morin in the chronic stages of trinitrobenzenesulphonic acid-induced rat colitis.

METHODS

Rats were rendered colitic by a single colonic instillation of 30 mg of the hapten trinitrobenzenesulphonic acid dissolved in 0.25 mL of 50% ethanol. A group of colitic animals was given morin orally at doses of 25 mg/kg daily. Animals were sacrificed every week for 4 weeks. Colonic damage was evaluated macroscopically and microscopically. Different biochemical markers of colonic inflammation were also assayed, including myeloperoxidase activity, leukotriene B4 and interleukin-1beta synthesis, glutathione and malonyldialdehyde levels and nitric oxide synthase activity.

RESULTS

The administration of morin facilitated tissue recovery during the 4 weeks following colonic insult with trinitrobenzenesulphonic acid, as demonstrated macroscopically and microscopically, as well as biochemically by a reduction in myeloperoxidase activity. The intestinal anti-inflammatory effect of morin was accompanied by a significant reduction in colonic leukotriene B4 and interleukin-1beta levels, improvement in colonic oxidative stress and inhibition of colonic nitric oxide synthase activity.

CONCLUSIONS

Morin exerts a beneficial anti-inflammatory effect in the chronic phase of trinitrobenzenesulphonic acid-induced rat colitis through the down-regulation of some of the mediators involved in the intestinal inflammatory response, including free radicals, cytokines, leukotriene B4 and nitric oxide.

Review article: balsalazide therapy in ulcerative colitis

Balsalazide is a 5-aminosalicylic acid (mesalazine) pro-drug which has an inert carrier molecule instead of the sulfapyridine moiety of sulfasalazine. It is designed to deliver 5-aminosalicylic acid to the colonic mucosa without the sulfapyridine-associated side-effects encountered with sulfasalazine. Several studies have confirmed the efficacy and patient tolerance of balsalazide. When compared to mesalazine at equivalent doses, it induced symptomatic and complete remission of acute ulcerative colitis in a greater proportion of patients. In particular, patients with resistant left-sided disease were shown to have a higher probability of achieving remission. Balsalazide was beneficial in patients with troublesome nocturnal symptoms. It has a similar efficacy in maintaining remission when compared to sulfasalazine and mesalazine. The advantage of balsalazide over other 5-aminosalicylic acid compounds is its superior patient tolerability with minimal side-effects.

Tolerability of aminosalicylates in inflammatory bowel disease

Since its synthesis in the 1930s and subsequent introduction, sulfasalazine has been an effective treatment for inflammatory bowel disease. However, up to one-third of patients are unable to take the drug because of severe intolerance. The finding in 1977 that the anticolitic effect of sulfasalazine lay in its 5-aminosalicylic [(5-ASA); mesalazine] moiety led to the development of new generations of 5-ASA agents. These new agents include a slow continuous release formulation, pH-dependent release formulations, formulations using alternative carrier molecules and rectally administered formulations. Newer 5-ASA formulations are more effective than placebo in maintaining remission of ulcerative colitis. They have also been used for the treatment of active Crohn's disease as well as maintenance treatment of ileocolonic Crohn's disease, although their role in isolated small bowel disease is controversial. In general terms, all of the newer 5-ASA preparations are much better tolerated than sulfasalazine. The use of standard dosages of mesalazine in pregnancy appears to be tolerated; however, continuing surveillance of pregnancy outcome is recommended. While there is evidence that mesalazine can cause nephrotoxic reactions, these reactions can occur with all 5-ASA-containing preparations, particularly in individuals with existing renal disease. Blood dyscrasias can also occur with all aminosalicylates.

Sulphasalazine inhibits macrophage activation: inhibitory effects on inducible nitric oxide synthase expression, interleukin-12 production and major histocompatibility complex II expression

The anti-inflammatory agent sulphasalazine is an important component of several treatment regimens in the therapy of ulcerative colitis, Crohn's disease and rheumatoid arthritis. Sulphasalazine has many immunomodulatory actions, including modulation of the function of a variety of cell types, such as lymphocytes, natural killer cells, epithelial cells and mast cells. However, the effect of this agent on macrophage (M phi) function has not been characterized in detail. In the present study, we investigated the effect of sulphasalazine and two related compounds - sulphapyridine and 5-aminosalicylic acid - on M phi activation induced by bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). In J774 M phi stimulated with LPS (10 microg/ml) and IFN-gamma (100 U/ml), sulphasalazine (50-500 microM) suppressed nitric oxide (NO) production in a concentration-dependent manner. The expression of the inducible NO synthase (iNOS) was suppressed by sulphasalazine at 500 microM. Sulphasalazine inhibited the LPS/IFN-gamma-induced production of both interleukin-12 (IL-12) p40 and p70. The suppression of both NO and IL-12 production by sulphasalazine was superior to that by either sulphapyridine or 5-aminosalicylic acid. Although the combination of LPS and IFN-gamma induced a rapid expression of the active forms of p38 and p42/44 mitogen-activated protein kinases and c-Jun terminal kinase, sulphasalazine failed to interfere with the activation of any of these kinases. Finally, sulphasalazine suppressed the IFN-gamma-induced expression of major histocompatibility complex class II. These results demonstrate that the M phi is an important target of the immunosuppressive effect of sulphasalazine.

Intestinal anti-inflammatory activity of UR-12746, a novel 5-ASA conjugate, on acute and chronic experimental colitis in the rat

The present study was undertaken to investigate the intestinal anti-inflammatory effects of UR-12746 on the acute and chronic stages of a trinitrobenzene sulphonic acid (TNBS) experimental model of inflammatory bowel disease (IBD) in the rat. UR-12746 is a novel, locally-acting compound which combines, through an azo bond, 5-aminosalicylic (5-ASA) and UR-12715, a potent platelet activating factor (PAF)-antagonist. UR-12746 oral pretreatment of colitic rats (50 and 100 mg kg(-1)) reduced acute colonic damage when evaluated 2 days after colonic insult. Postreatment for 4 weeks with UR-12746 (50 and 100 mg kg(-1)) resulted in a faster recovery of the damaged colonic mucosa, which was macroscopically significant from the third week. The intestinal anti-inflammatory effect of UR-12746 was associated with a decrease in leukocyte infiltration in the colonic mucosa, which was evidenced both biochemically, by a reduction in myeloperoxidase activity, and histologically, by a lower leukocyte count after morphometric analysis. This effect was higher than that seen with sulphasalazine, when assayed at the same doses and in the same experimental conditions. Several mechanisms can be involved in the beneficial effects showed by UR-12746: inhibition of leukotriene B(4) synthesis in the inflamed colon, improvement of the altered colonic oxidative status, and reduction of colonic interleukin-1beta production. The results suggest that the intestinal anti-inflammatory activity of UR-12746 can be attributed to the additive effects exerted by 5-ASA and UR-12715, the PAF antagonist compound, that are released in the colonic lumen after reduction of the azo bond by the intestinal bacteria.

Prolonged-release mesalazine: a review of its therapeutic potential in ulcerative colitis and Crohn's disease

Prolonged-release mesalazine (Pentasa) consists of ethylcellulose-coated microgranules from which mesalazine (known in the US as mesalamine) is released in the small and large intestine in a diffusion-dependent manner. Dose-dependent improvements in clinical and endoscopic parameters have been reported with prolonged-release mesalazine 2 and 4 g/day in clinical trials in patients with mild to moderately active ulcerative colitis. Induction of clinical and endoscopic remission was achieved in more patients receiving a daily dosage of 4 g/day than in those receiving placebo. In patients with ulcerative colitis in remission, prolonged-release mesalazine is effective in reducing the rate of relapse. Higher dosages tend to be more effective, and a 12-month remission rate of 64% has been reported for patients treated with a 4 g daily dosage of this formulation. Comparative data indicate that prolonged-release mesalazine has similar efficacy in maintaining remission to molar equivalent doses of sulfasalazine. Data from a study in patients with mild to moderately active Crohn's disease indicates that higher dosages (4 g/day) of prolonged-release mesalazine are more effective than placebo in reducing disease activity. After 16 weeks' treatment, 64% of patients receiving a 4 g/day dosage experienced clinical improvement and 43% attained remission. In studies of patients in remission of Crohn's disease, the formulation appears to be more effective in preventing relapse in patients with isolated small bowel disease than in those with colonic involvement. The tolerability profile of oral prolonged-release mesalazine is similar to that of placebo and the incidence of adverse events does not appear to be dose-related. Nausea/vomiting, diarrhoea, abdominal pain and dyspepsia occur most frequently, although their incidence is low. Reports of nephrotoxicity during prolonged-release mesalazine treatment are rare.

CONCLUSIONS

Oral prolonged-release mesalazine is effective for maintenance and induction of remission of mild to moderately active colitis, both in patients with distal disease and in those with pancolitis. The formulation has similar efficacy to that of equimolar concentrations of sulfasalazine. Prolonged-release mesalazine also appears to be effective in the treatment of Crohn's disease, and maintenance therapy is of particular value in patients with isolated small bowel involvement. Evidence suggests that higher dosages (3 to 4 g/day) of prolonged-release mesalazine have additional therapeutic benefits over lower dosages in patients with inflammatory bowel disease without increasing the incidence of adverse events.

Oral delayed-release mesalazine: a review of its use in ulcerative colitis and Crohn's disease

Oral delayed-release mesalazine is an enteric-coated formulation which releases mesalazine in the terminal ileum and colon. Up to 74% of patients with mild to moderately active ulcerative colitis experience endoscopic or symptomatic improvement (including remission) or both when treated with oral delayed-release mesalazine 2.4 to 4.8 g/day. There is a trend towards a better response in patients receiving higher daily dosages of oral delayed-release mesalazine, especially in patients with active distal disease. In patients with left-sided ulcerative colitis, oral balsalazide 6.75 g/day appears to be more effective than oral delayed-release mesalazine 2.4 g/day, but a higher dosage of oral delayed-release mesalazine 4.8 g/day may provide additional benefit in these patients. Oral delayed-release mesalazine 0.8 to 4.4 g/day appears to be as effective as sulfasalazine 2 to 4 g/day, prolonged-release mesalazine 1.5 g/day or balsalazide 3 g/day in maintaining remission in patients with ulcerative colitis. The optimal dosage of oral delayed-release mesalazine for the maintenance of remission is unclear. However, oral delayed-release mesalazine 1.6 g/day with rectal mesalazine 4g, administered twice weekly, was more effective than oral drug alone in maintaining remission in patients at high risk of relapse. In patients with left-sided or distal disease oral olsalazine 1 g/day appeared to be superior to oral delayed-release mesalazine 1.2 g/day for maintenance of symptomatic remission. Limited data in patients with Crohn's disease have shown oral delayed-release mesalazine 0.4 to 4.8 g/day to be an effective therapy for active disease (remission in up to 45% of patients) and for quiescent disease (relapse in 34% of recipients over a duration of up to 12 months). Preliminary data indicate that oral delayed-release mesalazine 2.4 g/day is effective in preventing postoperative recurrence of Crohn's disease. Oral delayed-release mesalazine is effective and well tolerated in sulfasalazine-intolerant patients with ulcerative colitis or Crohn's disease.

CONCLUSIONS

Oral delayed-release mesalazine is effective in patients with mild to moderately active or quiescent ulcerative colitis. Available data suggest that patients with left-sided or distal ulcerative colitis are likely to require higher daily dosages of oral delayed-release mesalazine or supplementation with rectal mesalazine. Oral delayed-release mesalazine also appears to be effective in active and quiescent Crohn's disease. The drug is well tolerated and it appears to be effective in sulfasalazine-intolerant patients.

Balsalazide

Balsalazide is a prodrug of mesalazine which has an inert carrier molecule instead of the sulfapyridine moiety of sulfasalazine. Balsalazide 6.75 g/day was more effective than mesalazine 2.4 g/day in at least 1 trial and as effective as sulfasalazine 3 g/day for inducing remission in patients with acute ulcerative colitis in 8- and 12-week trials. Moreover, complete symptom relief occurred more promptly with balsalizide 6.75 g/day than with mesalazine 2.4g/day. In long term studies, balsalazide 2 g/day was as effective as sulfasalazine 2 g/day and balsalazide 6 g/day was as effective as mesalazine 1.5 g/day, in maintaining remission in patients with ulcerative colitis. The tolerability profile of balsalazide is significantly better than that of sulfasalazine; 70% of sulfasalazine-intolerant patients were able to tolerate balsalazide.

In vivo butyrate metabolism and colonic permeability in extensive ulcerative colitis

BACKGROUND & AIMS

Impaired short-chain fatty acid metabolism by the colonocyte has been suggested as a pathogenic factor in ulcerative colitis (UC). The aim of this study was to measure in vivo butyrate metabolism in UC and to correlate butyrate oxidation with colonic permeability.

METHODS

Butyrate oxidation was measured by means of a 14CO2-breath test after rectal instillation of 14C-butyrate. 51Cr-ethylenediaminetetraacetic acid (EDTA) was added to the enema, and the urinary % dose excretion of 51Cr-EDTA after 6 hours was a measure for permeability.

RESULTS

Patients with active extensive UC showed a significantly lower butyrate oxidation and increased colonic permeability in comparison to healthy controls. Butyrate oxidation correlated significantly negative with clinical activity. Oxidation of butyrate was not decreased in most patients with inactive extensive UC. In 3 patients with inactive disease and decreased oxidation, a relapse occurred within a few weeks after the test, whereas all patients with normal oxidation maintained their remission for at least 3 months. A significantly negative correlation existed between butyrate oxidation and colonic permeability.

CONCLUSIONS

Patients with active extensive UC have a decreased colonic butyrate oxidation. However, the fact that remission is associated with normal oxidation suggests that UC mucosa is not intrinsically altered in butyrate oxidation, making this unlikely to be a primary defect in UC.

Balsalazide

Balsalazide is a prodrug of mesalazine which has an inert carrier molecule instead of the sulfapyridine moiety of sulfasalazine. Balsalazide 6.75 g/day was more effective than mesalazine 2.4 g/day in at least 1 trial and as effective as sulfasalazine 3 g/day for inducing remission in patients with acute ulcerative colitis in 8- and 12-week trials. Moreover, complete symptom relief occurred more promptly with balsalizide 6.75 g/day than with mesalazine 2.4g/day. In long term studies, balsalazide 2 g/day was as effective as sulfasalazine 2 g/day and balsalazide 6 g/day was as effective as mesalazine 1.5 g/day, in maintaining remission in patients with ulcerative colitis. The tolerability profile of balsalazide is significantly better than that of sulfasalazine; 70% of sulfasalazine-intolerant patients were able to tolerate balsalazide.

Colonic sulfide in pathogenesis and treatment of ulcerative colitis

A role for colonic sulfide in the pathogenesis and treatment of ulcerative colitis (UC) has emerged based on biochemical, microbiological, nutritional, toxicological, epidemiological, and therapeutic evidence. Metabolism of isolated colonic epithelial cells has indicated that the bacterial short-chain fatty acid n-butyrate maintains the epithelial barrier and that sulfides can inhibit oxidation of n-butyrate analogous to that observed in active UC. Sulfur for fermentation in the colon is essential for n-butyrate formation and sulfidogenesis aids disposal of colonic hydrogen produced by bacteria. The numbers of sulfate-reducing bacteria and sulfidogenesis is greater in UC than control cases. Sulfide is mainly detoxified by methylation in colonic epithelial cells and circulating red blood cells. The enzyme activity of sulfide methylation is higher in red blood cells of UC patients than control cases. Patients with UC ingest more protein and thereby sulfur amino acids than control subjects. Removing foods rich in sulfur amino acids (milk, eggs, cheese) has proven therapeutic benefits in UC. 5-Amino salicylic acid reduces fermentative production of hydrogen sulfide by colonic bacteria, and aminoglycosides, which inhibit sulfate-reducing bacteria, are of therapeutic benefit in active UC. Methyl-donating agents are a category of drugs of potential therapeutic use in UC. A correlation between sulfide production and mucosal immune responses in UC needs to be undertaken. Control of sulfidogenesis and sulfide detoxification may be important in the disease process of UC, although whether their roles is in an initiating or promoting capacity has yet to be determined.

Apoptosis of crypt epithelial cells in ulcerative colitis

In the colon of ulcerative colitis (UC) patients, apoptotic bodies have been recognized in routine histopathological preparations. To investigate the extent of the apoptosis, colonic biopsies were examined from involved and uninvolved areas of untreated active UC and from normal areas in patients with colonic polyps, utilizing various markers of apoptosis. The markers included DNA breaks detected by TUNEL, Fas (CD95/APO-1) and Fas ligand (Fas-L) localized by immunohistochemistry, electron microscopic features of apoptosis, and laddering of extracted DNA. Apoptosis marker positive cells were found mainly on the luminal epithelium of the normal colon and were present in active UC in crypts of involved and uninvolved areas of the colon, in addition to the luminal epithelium. The DNA extracted from active UC colon electrophoresed as a ladder. These findings suggest that the loss of epithelial cells in active UC occurs mainly by apoptosis in crypts of involved and adjacent uninvolved areas and that the Fas/Fas-L interaction is a mediator of the apoptosis.

Apoptosis of crypt epithelial cells in ulcerative colitis

In the colon of ulcerative colitis (UC) patients, apoptotic bodies have been recognized in routine histopathological preparations. To investigate the extent of the apoptosis, colonic biopsies were examined from involved and uninvolved areas of untreated active UC and from normal areas in patients with colonic polyps, utilizing various markers of apoptosis. The markers included DNA breaks detected by TUNEL, Fas (CD95/APO-1) and Fas ligand (Fas-L) localized by immunohistochemistry, electron microscopic features of apoptosis, and laddering of extracted DNA. Apoptosis marker positive cells were found mainly on the luminal epithelium of the normal colon and were present in active UC in crypts of involved and uninvolved areas of the colon, in addition to the luminal epithelium. The DNA extracted from active UC colon electrophoresed as a ladder. These findings suggest that the loss of epithelial cells in active UC occurs mainly by apoptosis in crypts of involved and adjacent uninvolved areas and that the Fas/Fas-L interaction is a mediator of the apoptosis.