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

Rapid Resolution of Large Bowel Diarrhea after the Administration of a Combination of a High-Fiber Diet and a Probiotic Mixture in 30 Dogs

Canine fiber responsive diarrhea is a form of chronic colitis that improves clinically after adding fiber to the diet. In the present study, we investigated the effect of a combination of a high-fiber, highly digestible, hypoallergenic diet with a probiotic mixture in 30 dogs with chronic colitis that were unresponsive to various dietary and/or pharmacological interventions. Fecal scores, canine chronic enteropathy clinical activity index (CCECAI) scores, the dysbiosis index (DI), and histologic images of colonic biopsies were evaluated. At baseline (day 0; T0) and after 30 days of treatment (T1), all variables evaluated in our patients (i.e., fecal and CCECAI scores and histopathology) improved significantly at T1, with the exception of DI. However, there was a numerical shift from a state of dysbiosis to one of normobiosis. The combination of the diet and the probiotic used in the present study induced the resolution of clinical signs in a mean of 8.5 days (maximum 15 days) and did not necessitate any other treatments or the further addition of alimentary fiber.

Importance of the Evaluation of N-Acetyltransferase Enzyme Activity Prior to 5-Aminosalicylic Acid Medication for Ulcerative Colitis

BACKGROUND

5-aminosalicylic acid (5-ASA) is a classic anti-inflammatory drug for the treatment of ulcerative colitis. N-acetyltransferase (NAT) enzymes convert 5-ASA to its metabolite N-acetyl-5-ASA, and it is unresolved whether 5-ASA or N-acetyl-5-ASA is the effective therapeutic molecule. We previously demonstrated that colonic production of N-acetyl-5-ASA (NAT activity) is decreased in dextran sulfate sodium-induced colitis. Our hypothesis is that 5-ASA is the therapeutic molecule to improve colitis, with the corollary that altered NAT activity affects drug efficacy. Since varying clinical effectiveness of 5-ASA has been reported, we also ask if NAT activity varies with inflammation in pediatric or adult patients.

METHODS

Acute colonic inflammation was induced in C57BL/6 NAT wild-type (WT) or knockout mice, using 3.5% dextran sulfate sodium (w/v) concurrent with 5-ASA treatment. Adult and pediatric rectosigmoid biopsies were collected from control or patients with ulcerative colitis. Tissue was analyzed for NAT and myeloperoxidase activity.

RESULTS

Dextran sulfate sodium-induced colitis was of similar severity in both NAT WT and knockout mice, and NAT activity was significantly decreased in NAT WT mice. In the setting of colitis, 5-ASA significantly restored colon length and decreased myeloperoxidase activity in NAT knockout but not in WT mice. Myeloperoxidase activity negatively correlated with NAT activity in pediatric patients, but correlation was not observed in adult patients.

CONCLUSIONS

Inflammation decreases NAT activity in the colon of mice and human pediatric patients. Decreased NAT activity enhances the therapeutic effect of 5-ASA in mice. A NAT activity assay could be useful to help predict the efficacy of 5-ASA therapy.

Safety and activity of dersalazine sodium in patients with mild-to-moderate active colitis: double-blind randomized proof of concept study

BACKGROUND

Dersalazine sodium is an inhibitor of platelet activator factor with potential efficacy in patients with ulcerative colitis through an alternative mechanism of action. The study was a first proof of clinical safety and activity of dersalazine sodium in patients with ulcerative colitis.

METHODS

A double-blind study of randomized patients with ulcerative colitis (Mayo score ≥ 5 and ≤ 10, including a sigmoidoscopy subscore ≥ 2) to dersalazine sodium 1200 mg/12 h, mesalazine 1200 mg/12 h, or placebo for 4 weeks. Mayo scores were calculated on week 2 (partial Mayo) and week 4 (full Mayo). All patients received open-label mesalazine for 4 additional weeks, and a final visit was done at week 8.

RESULTS

The study included 34 patients (13 dersalazine sodium, 10 mesalazine, and 11 placebo). Clinical remission was observed in 46.2% patients treated with dersalazine sodium versus 12.5% in mesalazine and 10% in placebo after 4 weeks of treatment. Colon biopsies showed significantly decreased expression of inflammatory genes in dersalazine sodium patients. Adverse events at least possibly related to treatment were observed in 23%, 12.5%, and 7.6% of patients receiving dersalazine sodium, mesalazine, and placebo, respectively; no serious adverse reactions were reported. Increased liver enzymes were reported in 2/13 patients receiving dersalazine sodium, with normal bilirubin levels; both returned to normal values on treatment interruption.

CONCLUSIONS

Studies in wider populations are needed to confirm the clinical activity of dersalazine sodium. Weekly measurements of liver function tests may be necessary for early detection of adverse events.

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.

Acute murine colitis reduces colonic 5-aminosalicylic acid metabolism by regulation of N-acetyltransferase-2

Pharmacotherapy based on 5-aminosalicylic acid (5-ASA) is a preferred treatment for ulcerative colitis, but variable patient response to this therapy is observed. Inflammation can affect therapeutic outcomes by regulating the expression and activity of drug-metabolizing enzymes; its effect on 5-ASA metabolism by the colonic arylamine N-acetyltransferase (NAT) enzyme isoforms is not firmly established. We examined if inflammation affects the capacity for colonic 5-ASA metabolism and NAT enzyme expression. 5-ASA metabolism by colonic mucosal homogenates was directly measured with a novel fluorimetric rate assay. 5-ASA metabolism reported by the assay was dependent on Ac-CoA, inhibited by alternative NAT substrates (isoniazid, p-aminobenzoylglutamate), and saturable with Km (5-ASA) = 5.8 μM. A mouse model of acute dextran sulfate sodium (DSS) colitis caused pronounced inflammation in central and distal colon, and modest inflammation of proximal colon, defined by myeloperoxidase activity and histology. DSS colitis reduced capacity for 5-ASA metabolism in central and distal colon segments by 52 and 51%, respectively. Use of selective substrates of NAT isoforms to inhibit 5-ASA metabolism suggested that mNAT2 mediated 5-ASA metabolism in normal and colitis conditions. Western blot and real-time RT-PCR identified that proximal and distal mucosa had a decreased mNAT2 protein-to-mRNA ratio after DSS. In conclusion, an acute colonic inflammation impairs the expression and function of mNAT2 enzyme, thereby diminishing the capacity for 5-ASA metabolism by colonic mucosa.

Evaluation of responsive gene expression as a sensitive and specific biomarker in patients with ulcerative colitis

BACKGROUND

Clinical trials in ulcerative colitis (UC) rely on certain parameters to evaluate responses that are highly subjective or of low sensitivity. Here, using a select group of genes, we tested the accuracy of gene expression analysis as a biomarker of clinical, endoscopic, and histologic improvements.

METHODS

Intestinal biopsies were obtained from UC patients included in two cohorts. Cohort 1 was used to select for genes whose expression was modulated in active (vs. inactive) UC. Cohort 2 included patients recruited in a phase II study receiving placebo, mesalazine, or dersalazine sodium for 4 weeks. The expression of 44 genes identified in Cohort 1 was assessed at weeks 0 and 4, and was then correlated with biomarkers, as well as with clinical, endoscopic, and histologic scores.

RESULTS

Significant changes in the expression of 31 of the 44 genes tested were detected in Cohort 2 at week 4. Gene expression (ΔCt) significantly correlated with the total Mayo score, C-reactive protein (CRP), and fecal calprotectin. The number of genes significantly regulated at week 4 was highly associated with histologic and endoscopic responses. Logistic regression analysis identified four separate genes (IFITM1, ITGB2, IL1R2, IL2RA) whose relative change was independently associated with endoscopic remission with high specificity and sensitivity.

CONCLUSIONS

Change in the expression of a select set of genes can serve as an early biomarker, one with high specificity and sensitivity to clinical, endoscopic, and histologic responses. This could represent a new tool for identifying early response to treatment in mild to moderately active UC patients.

The intestinal anti-inflammatory effect of dersalazine sodium is related to a down-regulation in IL-17 production in experimental models of rodent colitis

BACKGROUND AND PURPOSE

Dersalazine sodium (DS) is a new chemical entity formed by combining, through an azo bond, a potent platelet activating factor (PAF) antagonist (UR-12715) with 5-aminosalicylic acid (5-ASA). DS has been demonstrated to have anti-inflammatory effects on trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats and recently in UC patients in phase II PoC. There is Increasing evidence that Th17 cells have an important role in the pathogenesis of inflammatory bowel disease (IBD). The aim of this study was to further characterize the anti-inflammatory effects of DS.

EXPERIMENTAL APPROACH

Effect of DS (10 or 30 mg·kg(-1) b.i.d.) on TNBS-induced colitis in rats was studied after 2 and 7 days with special focus on inflammatory mediators. Additionally, its anti-inflammatory properties were analysed in two different models of dextran sodium sulphate (DSS)-induced colitis, BALB/c and C57BL/6 mice, the latter being dependent on IL-17.

KEY RESULTS

DS, when administered for 7 days, showed intestinal anti-inflammatory effects in TNBS-induced colitis; these effects were observed both macroscopically and through the profile of inflammatory mediators (TNF, IL-1β, IL-6 and IL-17). Although the 2 day treatment with DS did not induce intestinal anti-inflammatory effects, it was sufficient to reduce the enhanced IL-17 expression. DS showed beneficial effects on DSS-induced colitis in C57BL/6 mice and reduced colonic pro-inflammatory cytokines IL-1β, IL-6 and IL-17. In contrast, it did not exert intestinal anti-inflammatory effects on DSS-induced colitis in BALB/c mice.

CONCLUSIONS AND IMPLICATIONS

DS exerts intestinal anti-inflammatory activity in different rodent models of colitis through down-regulation of IL-17 expression.

New light on the anti-colitic actions of therapeutic aminosalicylates: the role of heme oxygenase

Although a variety of pharmaceutical preparations of aminosalicylate are commonly used in the clinic for the control of inflammatory bowel disease, the mechanisms underlying their therapeutic actions remain unclear. Recent in vivo and in vitro studies have demonstrated that 5-aminosalicylic acid (5-ASA), regarded as the active moiety in aminosalicylate preparations such as sulfasalazine, can induce the heat shock protein, heme oxygenase-1 (HO-1) and up-regulate HO enzyme activity in the colon. As HO-1 can produce endogenous anti-oxidant and anti-inflammatory moieties such as bilirubin and carbon monoxide (CO), these findings suggest a novel mechanism of action for aminosalicylates, acting as anti-colitic agents through the up-regulation of HO-1 enzyme expression and activity.

Emerging drugs for the treatment of ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic, relapsing inflammatory disorder of the colon for which the etiology is currently unknown. At present, strategies to treat UC are primarily targeted to control inflammation during active phases of disease as well as maintain remission during quiescence. As such, several unmet needs in the treatment of UC still remain. In recent years, basic research has led to the recognition of several key factors in the pathogenesis of UC, translating into the development of several novel therapeutic agents.

OBJECTIVE

The aim of this study is to review emerging therapies that may advance the treatment and improve the overall care of UC patients.

METHODS

An extensive literature search on published manuscripts and meeting proceedings has been performed to provide a comprehensive review of future drug therapies to treat UC.

RESULTS/CONCLUSION

The translational application of new discoveries in the basic understanding of UC pathogenesis is continuing and critical for the development of novel treatment strategies. Design of novel biologic therapies to treat UC has the challenge of addressing potential safety issues, while more traditional drugs should be further developed to facilitate patient compliance to treat this chronic, debilitating disease.

Relationship between mast cells and the colitis with relapse induced by trinitrobenzesulphonic acid in Wistar rats

The present study aimed to clarify the role of mast cells in colitis with relapse induced in Wistar rats by trinitrobenzenosulphonic acid. Colitis induction increased the histamine concentration in the colon, which peaked on day 26. The number of mast cells, probably immature, was ten times higher on day 8. Different from animals infected with intestinal parasites, after colitis remission, mast cells do not migrate to the spleen, showing that mast cell proliferation presents different characteristics depending on the inflammation stimuli. Treatment with sulfasalazine, doxantrazole, quercetin, or nedocromil did not increase the histamine concentration or the mast cell number in the colon on day 26, thereby showing absence of degranulation of these cells. In conclusion, although mast cell proliferation is associated with colitis, these cells and their mediators appear to play no clear role in the colitis with relapses.

Interleukin-1 and ischemic brain injury in the newborn: development of a small molecule inhibitor of IL-1 receptor

Inflammation participates in the genesis and progression of hypoxic-ischemic brain injury. Interleukin (IL)-1 is a major pro-inflammatory cytokine, which plays a dominant role in hypoxic-ischemic (and postinfectious) brain damage. Abundant evidence reveals the principal involvement of IL-1 over other pro-inflammatory cytokines. IL-1 interacts with the IL-1 receptor I (IL-1RI). The natural IL-1 receptor antagonist (IL-1ra) is a large 17.5-kDa peptide that competes with IL-1 for its binding site on IL-1RI. Recombinant IL-1ra (Kineret) is effective in human inflammatory conditions. However, a number of drawbacks of IL-1ra limit its broader use; these include injection site reactions [70%], broad immunosuppression, and high costs. We hereby report the characterization of a small (peptide) IL-1RI antagonist we developed, namely rytvela (termed 101.10), and its efficacy in models of (gut) inflammation and of newborn hypoxic-ischemic brain injury. Experiments reveal that 101.10 is selective for the IL-1RI and inhibits to a variable extent different effects induced by IL-1. 101.10 is effective in vivo (on systemic as well as oral administration) in established models of inflammation involving IL-1, notably in inflammatory bowel disease, and is superior to dexamethasone. In a rat pup model of hypoxic-ischemic brain injury (Rice-Vannucci model), where IL-1 and IL-1R expression is increased, 101.10 preserved microvascular density, parenchymal integrity, and brain mass. In conclusion, we hereby describe for the first time the discovery of a stable, potent, and effective specific IL-1RI small (peptide) antagonist, namely 101.10 (rytvela), which exhibits allosteric modulatory properties, and is effective in vivo in models of inflammation (known to involve IL-1) and in particular in hypoxic-ischemic newborn brain injury. 101.10 (and small alike compounds) may be suitable alternatives to IL-1ra.

Development of a novel noncompetitive antagonist of IL-1 receptor

IL-1 is a major proinflammatory cytokine which interacts with the IL-1 receptor I (IL-1RI) complex, composed of IL-1RI and IL-1R accessory protein subunits. Currently available strategies to counter pathological IL-1 signaling rely on a recombinant IL-1 receptor antagonist, which directly competes with IL-1 for its binding site. Presently, there are no small antagonists of the IL-1RI complex. Given this void, we derived 15 peptides from loops of IL-1R accessory protein, which are putative interactive sites with the IL-1RI subunit. In this study, we substantiate the merits of one of these peptides, rytvela (we termed "101.10"), as an inhibitor of IL-1R and describe its properties consistent with those of an allosteric negative modulator. 101.10 (IC(50) approximately 1 nM) blocked human thymocyte proliferation in vitro, and demonstrated robust in vivo effects in models of hyperthermia and inflammatory bowel disease as well as topically in contact dermatitis, superior to corticosteroids and IL-1ra; 101.10 did not bind to IL-1RI deficient cells and was ineffective in vivo in IL-1RI knockout mice. Importantly, characterization of 101.10, revealed noncompetitive antagonist actions and functional selectivity by blocking certain IL-1R pathways while not affecting others. Findings describe the discovery of a potent and specific small (peptide) antagonist of IL-1RI, with properties in line with an allosteric negative modulator.

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.

The involvement of heme oxygenase-1 activity in the therapeutic actions of 5-aminosalicylic acid in rat colitis

The mechanism of action of 5-aminosalicylic acid (5-ASA), the active therapeutic moiety of a number of clinically used anti-colitic agents, is unclear. The present study investigates whether the beneficial effects in vivo could involve induction of the heat shock protein, heme oxygenase-1 (HO-1), known to provide endogenous anti-oxidant and anti-inflammatory moieties which can modulate colonic inflammation. The effects of 5-ASA on the colonic expression and activity of HO-1 along with its effect on the inflammatory damage have been evaluated in the colitis provoked by instillation of trinitrobenzene sulphonic acid (TNBS) over 48 h in the rat. Intracolonic administration of 5-ASA (8, 25 and 75 mg/kg/day) dose-dependently reduced the TNBS-provoked macroscopic colonic inflammatory injury, myeloperoxidase (MPO) activity and TNF-alpha levels, while also dose-dependently increasing colonic heme oxygenase enzyme activity. Colonic HO-1 protein expression, determined by Western blot analysis in this colitis model, was likewise further induced by 5-ASA. Intracolonic administration of 5-ASA alone under unchallenged conditions also induced colonic HO-1 protein expression and stimulated heme oxygenase enzyme activity. Administration of zinc protoporphyrin (50 micromol/kg/day, s.c.), which prevented the increase in colonic heme oxygenase activity, abolished the anti-colitic effect of 5-ASA. These results suggest that 5-ASA may exert its colonic anti-oxidant and anti-inflammatory effects in vivo in part through the up-regulation of HO-1 enzyme expression and activity.

Mesenteric adipose tissue alterations resulting from experimental reactivated colitis

BACKGROUND

Adipose tissue secretes a large number of hormones that act either locally or at distant sites, modulating immune responses, inflammation, and many endocrine and metabolic functions. Abnormalities of fat in the mesentery have been long recognized in surgical specimens as characteristic features of Crohn's disease; however, the importance of this in chronic inflammatory disease is unknown. Additionally, adipocytes in depots that enclose lymph nodes or other dense masses of lymphoid tissue have many site-specific physiological properties.

METHODS

In this study, the alterations of mesenteric and perinodal mesenteric adipose tissue during experimental colitis, induced by repeated intracolonic trinitrobenzene sulfonic acid instillations, were evaluated, focusing on morphological and activity alterations and the adipocytokine production profile.

RESULTS

After a 35-day protocol, the colitis animals presented greater mesenteric fat masses despite their lower body weights. Another adipose tissue depot, epididymal adipose tissue, was also evaluated and no change in mass was observed. The mesenteric adipocyte from colitis animals had a reduced diameter, normal PPAR-gamma-2 expression, and higher basal lipolysis and TNF-alpha production when compared to normal rats. Perinodal mesenteric adipocytes present normal diameters, downregulated levels of PPAR-gamma-2, higher basal lipolysis and TNF-alpha, and leptin and adiponectin production.

CONCLUSIONS

The findings suggest that mesenteric adipose tissue has a site-specific response during experimental inflammation, where perinodal adipose tissue retains the ability to produce different adipocytokines. These substances may interfere in many lymph node aspects, while mesenteric adipose tissue produces substances that could contribute directly to aggravate the inflammatory process.

The intestinal anti-inflammatory effects of the novel agent UR-1505 in the TNBS model of rat colitis are mediated by T-lymphocyte inhibition

UR-1505 is a novel pentafluoropropoxy derivative of salicylic acid, selected from a series of salicylate derivatives, according to their activity as inhibitors of T-lymphocyte activation. This study describes the anti-inflammatory activity of UR-1505 on trinitrobenzenesulphonic acid-induced colitis in rat, an experimental model that resembles to Crohn's disease (CD), as well as its in vitro effects on T-cells and bone marrow-derived macrophages (BMDM) activation. UR-1505 showed intestinal anti-inflammatory effect, associated with reduced colonic levels of TNFalpha and LTB(4), inhibition of the expression of IFNgamma and iNOS, and lower colonic leukocyte infiltration. The in vitro assays revealed that UR-1505 also inhibited T-lymphocyte proliferation and IL-12/IFNgamma production, two of the main pro-inflammatory cytokines involved in the pathogenesis of CD. However, UR-1505 did not modify LPS- nor IFNgamma-induced activation in BMDM. Thus, UR-1505 specifically affects T-cells without modifying the activation of BMDM. In conclusion, the intestinal anti-inflammatory activity of UR-1505 seems to be mediated by a reduction in the recruitment of immune cells to the inflammatory foci, together with the inhibition of T-cell activation. These results suggest that UR-1505 may be an interesting candidate to be explored for the treatment of CD.

A comparative study of the preventative effects exerted by two probiotics, Lactobacillus reuteri and Lactobacillus fermentum, in the trinitrobenzenesulfonic acid model of rat colitis

The intestinal anti-inflammatory effects of two probiotics isolated from breast milk, Lactobacillus reuteri and L. fermentum, were evaluated and compared in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis. Colitis was induced in rats by intracolonic administration of 10 mg TNBS dissolved in 50% ethanol (0.25 ml). Either L. reuteri or L. fermentum was daily administered orally (5 x 10(8) colony-forming units suspended in 0.5 ml skimmed milk) to each group of rats (n 10) for 3 weeks, starting 2 weeks before colitis induction. Colonic damage was evaluated histologically and biochemically, and the colonic luminal contents were used for bacterial studies and for SCFA production. Both probiotics showed intestinal anti-inflammatory effects in this model of experimental colitis, as evidenced histologically and by a significant reduction of colonic myeloperoxidase activity (P<0.05). L. fermentum significantly counteracted the colonic glutathione depletion induced by the inflammatory process. In addition, both probiotics lowered colonic TNFalpha levels (P<0.01) and inducible NO synthase expression when compared with non-treated rats; however, the decrease in colonic cyclo-oxygenase-2 expression was only achieved with L.fermentum administration. Finally, the two probiotics induced the growth of Lactobacilli species in comparison with control colitic rats, but the production of SCFA in colonic contents was only increased when L. fermentum was given. In conclusion, L. fermentum can exert beneficial immunomodulatory properties in inflammatory bowel disease, being more effective than L. reuteri, a probiotic with reputed efficacy in promoting beneficial effects on human health.

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.

Antioxidant therapy with N-acetylcysteine plus mesalamine accelerates mucosal healing in a rodent model of colitis

The aims of this study were to examine the ability of the antioxidant N-acetylcysteine (NAC) and mesalamine (5-ASA) alone and in combination to affect TNBS-induced colitis in rat. Three days following induction of TNBS colitis rats were randomized to receive daily intracolonic treatment with NAC, 5-ASA, and NAC plus 5-ASA for 5 or 8 days. At the end of the treatment period macroscopic and microscopic colonic injuries were scored. Myeloperoxidase (MPO) activity and cytokine gene expression were measured in colonic tissues. Results indicated that treatment with NAC plus 5-ASA caused a significantly greater reduction in colonic injury than either agent alone. Furthermore, combination therapy inhibited significantly MPO activity and inflammatory cytokine gene expression in the distal colon of TNBS-treated animals. The beneficial effects of NAC plus 5-ASA on reduction of colonic injury and promotion of healing were most evident after 8 days of treatment.

Cytokines and neutrophils as important mediators of platelet-activating factor-induced kinin B1 receptor expression

PAF injection into the rat paw is accompanied by the concomitant activation of NF-kappaB and neutrophil influx, which appears to be relevant to the up-regulation of kinin B1 receptors. Herein, we analyse the role of TNF-alpha and IL-1beta production for PAF-induced B1 receptor upregulation in the rat paw. Additionally, we evaluate how cytokine production and neutrophil migration fit into the temporal sequence of events leading to PAF-induced B1 receptor upregulation. In our experiments, treatment with PAF resulted in a marked increase of B1 receptor-mediated paw oedema and in situ production of TNF-alpha at 1 h and IL-1beta at 3 and 6 h later. B1 receptor-mediated paw oedema was significantly inhibited by anti-TNF-alpha antibody and by interleukin-1 receptor antagonist (IRA). TNF-alpha was necessary for the local PAF-induced IL-1beta production. NF-kappaB blocker PDTC prevented the production of both TNF-alpha and IL-1beta, indicating that cytokine production is NF-kappaB dependent. Depletion of neutrophils with an anti-PMN antibody prevented IL-1beta, but not TNF-alpha, production. Although both TNF-alpha and IL-1beta are relevant to functional B1 receptor upregulation, PAF-induced increase in B1 receptor mRNA was markedly suppressed by anti-TNF-alpha and, to a lesser extent, by IRA. B1 receptor mRNA expression was also prevented by the anti-PMN antibody. In conclusion, the activation of the TNF-alpha/neutrophil axis by PAF seems to be sufficient for B1 receptor mRNA production. However, the TNF-alpha/neutrophil axis is also necessary for IL-1beta production. These two processes might lead to the appearance of functional kinin B1 upregulation receptors in vivo after PAF treatment.

Preventative effects of a probiotic, Lactobacillus salivarius ssp. salivarius, in the TNBS model of rat colitis

AIM: To investigate the intestinal anti-inflammatory effect and mechanism of a probiotic Lactobacillus salivarius ssp. salivarius CECT5713 in the TNBS model of rat colitis.

METHODS: Female Wistar rats (180-200 g) were used in this study. A group of rats were administered orally the probiotic L. salivarius ssp. salivarius (5×10⁸ CFU suspended in 0.5 mL of skimmed milk) daily for 3 wk. Two additional groups were used for reference, a non-colitic and a control colitic without probiotic treatment, which received orally the vehicle used to administer the probiotic. Two weeks after starting the experiment, the rats were rendered colitic by intracolonic administration of 10 mg of TNBS dissolved in 0.25 mL of 500 mL/L ethanol. One week after colitis induction, all animals were killed and colonic damage was evaluated both histologically and biochemically. The biochemical studies performed in colonic homogenates include determination of myeloperoxidase (MPO) activity, glutathione (GSH) content, leukotriene B₄ (LTB₄) and tumor necrosis factor α (TNF-α) levels, as well as inducible nitric oxide synthase (iNOS) expression. In addition, the luminal contents obtained from colonic samples were used for microbiological studies, in order to determine Lactobacilli and Bifidobacteria counts.

RESULTS: Treatment of colitic rats with L. salivarius ssp. salivarius resulted in amelioration of the inflammatory response in colitic rats, when compared with the corresponding control group without probiotic treatment. This anti-inflammatory effect was evidenced macroscopically by a significant reduction in the extent of colonic necrosis and/or inflammation induced by the administration of TNBS/ethanol (2.3±0.4 cm vs 3.4±0.3 cm in control group, P<0.01) and histologically by improvement of the colonic architecture associated with a reduction in the neutrophil infiltrate in comparison with non-treated colitic rats. The latter was confirmed biochemically by a significant reduction of colonic MPO activity (105.3±26.0 U/g vs 180.6±21.9 U/g, P<0.05), a marker of neutrophil infiltration. The beneficial effect was associated with an increase of the colonic GSH content (1 252±42 nmol/g vs 1 087±51 nmol/g, P<0.05), which is depleted in colitic rats, as a consequence of the oxidative stress induced by the inflammatory process. In addition, the treatment of colitic rats with L. salivarius resulted in a significant reduction of colonic TNF-α levels (509.4±68.2 pg/g vs 782.9±60.1 pg/g, P<0.01) and in a lower colonic iNOS expression, when compared to TNBS control animals without probiotic administration. Finally, treated colitic rats showed higher counts of Lactobacilli species in colonic contents than control colitic rats, whereas no differences were observed in Bifidobacteria counts.

CONCLUSION: Administration of the probiotic L. salivarius ssp. salivarius CECT5713 facilitates the recovery of the inflamed tissue in the TNBS model of rat colitis, an effect associated with amelioration of the production of some of the mediators involved in the inflammatory response in the intestine, such as cytokines, including TNF-α and NO. This beneficial effect could be ascribed to its effect on the altered immune response that occurs in this inflammatory condition.

Colonic targeting of aminosalicylates for the treatment of ulcerative colitis

Aminosalicylates (5-aminosalicylic acid) represent drugs of first choice in the treatment of ulcerative colitis. Two different therapeutic approaches have been employed to target the active 5-aminosalicylic acid to its site of action. Either inactive azo-prodrugs (e.g. sulfasalazine, olsalazine, balsalazide) or special galenic formulations have been developed for topical delivery of 5-aminosalicylic acid to the colon. However, as intestinal physiology, the extent of ulcerative colitis as well as drug disposition demonstrate large interindividual differences, acute healing rates (40-80%) and the maintenance of remission are quite variable. Apparently, therapeutic effects depend on local concentrations of 5-aminosalicylic acid in the colonic mucosa whereas systemic drug exposure might be one determinant of side effects. In general, 5-aminosalicylic acid is well tolerated and withdrawal from therapy is rare. Following administration of azo-prodrugs (e.g. olsalazine), lower plasma concentrations and higher delivery into the colon of 5-aminosalicylic acid can be observed in comparison to special galenic formulations of 5-aminosalicylic acid. Whether such changes in drug disposition will affect therapeutic efficacy remains to be proved by clinical data. Consequently, selection of a particular agent should be based primarily on clinical efficacy, profile of adverse effects, patients' acceptance and economic considerations.

Preventative effects of lactulose in the trinitrobenzenesulphonic acid model of rat colitis

AIMS

Lactulose is a drug used as a laxative that has been shown to promote the growth of lactobacilli and bifidobacteria, acting as a prebiotic and with a potential beneficial effect in inflammatory bowel disease. The present study describes the preventive antiinflammatory activity of lactulose in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis.

METHODS

Rats were rendered colitic by a colonic instillation of 10 mg of TNBS dissolved in 0.25 mL of 50% ethanol. One group of colitic rats received lactulose, which was incorporated in the drinking water (2.5% wt/vol) for 2 weeks before TNBS instillation, and colonic damage was evaluated 1 week after colitis induction. Different biochemical markers of colonic inflammation were assayed: myeloperoxidase activity, glutathione content, tumor necrosis factor alpha, leukotriene B4 levels, and colonic inducible nitric oxide synthase expression. In addition, bacterial counts (for lactobacilli and bifidobacteria) were performed in colonic contents from colitic rats.

RESULTS

The results show that lactulose exerted a preventive antiinflammatory effect in this model of rat colitis, as evidenced by a significant reduction of myeloperoxidase activity and by a decrease of both colonic tumor necrosis factor alpha and leukotriene B4 production. This effect was also characterized by an inhibition of colonic inducible nitric oxide synthase expression, which is unregulated as a consequence of the inflammatory status. This beneficial effect was associated with increased levels of lactobacilli and bifidobacteria species in colonic contents in comparison with untreated colitic rats.

CONCLUSION

In conclusion, the intestinal antiinflammatory effect of lactulose could be related to its prebiotic properties, supporting its potential use in human inflammatory bowel disease.