Involvement of neutrophils and free radicals in the potentiating effects of passive cigarette smoking on inflammatory bowel disease in rats

Chronic Exposure to Both Electronic and Conventional Cigarettes Alters Ileum and Colon Turnover, Immune Function, and Barrier Integrity in Mice

Although the effects of cigarette smoke (CS) on the development of several intestinal diseases is well documented, the impact of e-cigarette aerosol (e-cig) on digestive health is largely unknown. To compare the effects of e-cig and CS on mouse ileum and colon, animals were chronically exposed for 6 months by nose-only inhalation to e-cig at 18 or 30 W power, or to 3R4F CS. Results showed that e-cig exposure decreased colon cell proliferation. Several other proliferative defects were observed in response to both e-cig and CS exposure, including up- and down-regulation of cyclin D1 protein levels in the ileum and colon, respectively. E-cig and CS exposure reduced myeloperoxidase activity in the ileum. In the colon, both exposures disrupted gene expression of cytokines and T cell transcription factors. For tight junction genes, ZO-1- and occludin-protein expression levels were reduced in the ileum and colon, respectively, by e-cig and CS exposure. The 16S sequencing of microbiota showed specific mild dysbiosis, according to the type of exposure. Overall, e-cig exposure led to altered proliferation, inflammation, and barrier function in both the ileum and colon, and therefore may be a gut hazard on par with conventional CS.

Translational research into the effects of cigarette smoke on inflammatory mediators and epithelial TRPV1 in Crohn's disease

Crohn's disease is a pathological condition of the gastro-intestinal tract, causing severe transmural inflammation in the ileum and/or colon. Cigarette smoking is one of the best known environmental risk factors for the development of Crohn's disease. Nevertheless, very little is known about the effect of prolonged cigarette smoke exposure on inflammatory modulators in the gut. We examined the effect of cigarette smoke on cytokine profiles in the healthy and inflamed gut of human subjects and in the trinitrobenzene sulphonic acid mouse model, which mimics distal Crohn-like colitis. In addition, the effect of cigarette smoke on epithelial expression of transient receptor potential channels and their concurrent increase with cigarette smoke-augmented cytokine production was investigated. Active smoking was associated with increased IL-8 transcription in ileum of controls (p < 0,001; n = 18-20/group). In the ileum, TRPV1 mRNA levels were decreased in never smoking Crohn's disease patients compared to healthy subjects (p <0,001; n = 20/group). In the colon, TRPV1 mRNA levels were decreased (p = 0,046) in smoking healthy controls (n = 20/group). Likewise, healthy mice chronically exposed to cigarette smoke (n = 10/group) showed elevated ileal Cxcl2 (p = 0,0075) and colonic Kc mRNA levels (p = 0,0186), whereas TRPV1 mRNA and protein levels were elevated in the ileum (p = 0,0315). Although cigarette smoke exposure prior to trinitrobenzene sulphonic acid administration did not alter disease activity, increased pro-inflammatory cytokine production was observed in the distal colon (Kc: p = 0,0273; Cxcl2: p = 0,104; Il1-β: p = 0,0796), in parallel with the increase of Trpv1 mRNA (p < 0,001). We infer that CS affects pro-inflammatory cytokine expression in healthy and inflamed gut, and that the simultaneous modulation of TRPV1 may point to a potential involvement of TRPV1 in cigarette smoke-induced production of inflammatory mediators.

Review article: impact of cigarette smoking on intestinal inflammation-direct and indirect mechanisms

BACKGROUND

The inflammatory bowel diseases, Crohn's disease and ulcerative colitis are related multifactorial diseases. Their pathogenesis is influenced by each individual's immune system, the environmental factors within exposome and genetic predisposition. Smoking habit is the single best-established environmental factor that influences disease phenotype, behaviour and response to therapy.

AIM

To assess current epidemiological, experimental and clinical evidence that may explain how smoking impacts on the pathogenesis of inflammatory bowel disease.

METHODS

A Medline search for 'cigarette smoking', in combination with terms including 'passive', 'second-hand', 'intestinal inflammation', 'Crohn's disease', 'ulcerative colitis', 'colitis'; 'intestinal epithelium', 'immune system', 'intestinal microbiota', 'tight junctions', 'mucus', 'goblet cells', 'Paneth cells', 'autophagy'; 'epigenetics', 'genes', 'DNA methylation', 'histones', 'short noncoding/long noncoding RNAs'; 'carbon monoxide/CO' and 'nitric oxide/NO' was performed.

RESULTS

Studies found evidence of direct and indirect effects of smoking on various parameters, including oxidative damage, impairment of intestinal barrier and immune cell function, epigenetic and microbiota composition changes, that contribute to the pathogenesis of inflammatory bowel disease.

CONCLUSIONS

Cigarette smoking promotes intestinal inflammation by affecting the function and interactions among intestinal epithelium, immune system and microbiota/microbiome.

Frequency and risk factors of surgical recurrence of Crohn's disease after primary bowel resection

BACKGROUND/AIMS

The purpose of this study was to evaluate the frequency and risk factors associated with Crohn's disease (CD) reoperation after primary bowel resection.

MATERIALS AND METHODS

We identified 166 patients suffering from CD with primary bowel resection and primary anastomosis from the clinical database of a university hospital. The cumulative recurrence rate and median recurrence-free survival (RFS) were calculated using the Kaplan-Meier analysis. Categorical variables were compared using a log-rank test. A Cox proportional hazard model was used for multivariate analysis.

RESULTS

The median age of reoperation was 30 years, and the median RFS was 30 months. The reoperation intervention rate was 16.9%. It was shown that smoking (p=0.015) and jejunoileal anastomosis (p=0.002) were significantly closely correlated to an increased risk of surgical recurrence, whereas laparoscopy (p=0.039), side-to-side anastomosis (p=0.018), and anastomotic stoma wider than 3 cm (p=0.024) were significantly closely correlated to a reduced risk of surgical recurrence.

CONCLUSION

This study provided a robust result that smoking and small intestinal lesions were the risk factors of surgical recurrence for patients with CD upon the initial gut resection. Laparoscopy, side-to-side anastomosis, and wide anastomotic stoma were found to be protective factors against surgical recurrence.

Comparative Efficacy of Chitosan, Pectin Based Mesalamine Colon Targeted Drug Delivery Systems on TNBS-induced IBD Model Rats

OBJECTIVE

A number of natural polymer-based drug delivery systems targeting the colon are reported for different applications. Most of the research is based on the class of natural polymers such as polysaccharides. This study compares the anti-inflammatory effect of different polysaccharide based tablets on IBD when a drug carrier is targeted to the colon as matrix and coated systems.

METHODS

The TNBS induced IBD Wistar rats were used as a model for the study. The microscopic and macroscopic parameters were studied in detail. Almost all the important IBD parameters were reported in this work.

RESULTS

The results demonstrated that the polysaccharides are efficient in carrying the drugs to the colon. Reduction in the level of ulcer index (UI), Myeloperoxidase (MPO), and Malondialdehyde MDA, confirmed the inhibitory activity on the development of Reactive oxygen species (ROS). The increased level of Tumor necrosis factor (TNFα) an expression of colonic inducible nitric oxide synthase (iNOS) was lowered in treatments as compared to TNBS control.

CONCLUSION

The different polymer-based mesalamine (DPBM) confirmed the efficient anti- inflammatory activity on IBD induced rats. The increased level of glutathione (GSH), and superoxide dismutase (SOD) also confirmed the effective anti-inflammatory effect. A significant decrease in the ulcer score and ulcer area was reported. The investigation revealed that chitosan is superior to pectin in IBD treatment likewise polysaccharide-based matrix systems are superior to the coated system.

Cellular Stress Responses and Gut Microbiota in Inflammatory Bowel Disease

Progresses in the past two decades have greatly expanded our understanding of inflammatory bowel disease (IBD), an incurable disease with multifaceted and challenging clinical manifestations. The pathogenesis of IBD involves multiple processes on the cellular level, which include the stress response signaling such as endoplasmic reticulum (ER) stress, oxidative stress, and hypoxia. Under physiological conditions, the stress responses play key roles in cell survival, mucosal barrier integrity, and immunomodulation. However, they can also cause energy depletion, trigger cell death and tissue injury, promote inflammatory response, and drive the progression of clinical disease. In recent years, gut microflora has emerged as an essential pathogenic factor and therapeutic target for IBD. Altered compositional and metabolic profiles of gut microbiota, termed dysbiosis, are associated with IBD. Recent studies, although limited, have shed light on how ER stress, oxidative stress, and hypoxic stress interact with gut microorganisms, a potential source of stress in the microenvironment of gastrointestinal tract. Our knowledge of cellular stress responses in intestinal homeostasis as well as their cross-talks with gut microbiome will further our understanding of the pathogenesis of inflammatory bowel disease and probably open avenues for new therapies.

Pathomechanisms of Oxidative Stress in Inflammatory Bowel Disease and Potential Antioxidant Therapies

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease whose incidence has risen worldwide in recent years. Accumulating evidence shows that oxidative stress plays an essential role in the pathogenesis and progression of IBD. This review highlights the generation of reactive oxygen species (ROS) and antioxidant defense mechanisms in the gastrointestinal (GI) tract, the involvement of oxidative stress signaling in the initiation and progression of IBD and its relationships with genetic susceptibility and the mucosal immune response. In addition, potential therapeutic strategies for IBD that target oxidative stress signaling are reviewed and discussed. Though substantial progress has been made in understanding the role of oxidative stress in IBD in humans and experimental animals, the underlying mechanisms are still not well defined. Thus, further studies are needed to validate how oxidative stress signaling is involved in and contributes to the development of IBD.

Evaluation of Antiulcer and Antioxidant Activity of Barleria gibsoniDalz. Leaves

BACKGROUND

Peptic ulcer is a digestive disorder most commonly found in clinical practice. Given the many side effects of modern medicine, the initial acquisition of fewer side effects, and medication of indigenous drugs, it should be considered as a better alternative for the treatment of peptic ulcer.

OBJECTIVE

To assess antiulcer and antioxidant activity of ethanol extract of Barleria gibsoni (EBG) Dalz. leaves in ulcer-induced rats and in vitro antioxidants method, respectively.

MATERIALS AND METHODS

Ethanol EBG was screened for antiulcer activity in pylorus ligation-induced ulcer models in Wistar rats. In vitro antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) radical scavenging activity. Total phenol and flavonoid content in the extracts were determined spectrophotometrically.

RESULTS

Oral administration of ethanol extract of leaves at doses of 250, 500 mg/kg p.o. reduced significant gastric lesions induced by pylorus ligation-induced ulcer as compared to standard omeprazole (20 mg/kg p.o.). The IC₅₀ values were found to be 150 μg/mL in leaves extract. The ethanol extracts showed good antioxidant capacity in DPPH radical scavenging assay and NO radical scavenging activity when compared to standard. The total phenolic content using Folin-Ciocalteu reagent estimated in 1 mg of leaves extracts was 368 μg and 481 μg with gallic acid equivalent and also the total flavonoid content found to be 240 and 410 μg, respectively, with quercetin equivalence.

CONCLUSION

These findings suggest that the leaves of B. gibsoni possessed antiulcer potential and antioxidant compared to standard. This is the first ever report of antiulcer and antioxidant activities in B. gibsoni (Acanthaceae).

SUMMARY

In vivo antiulcer and in vitro antioxidant activity of Barleria gibsoni was evaluated.Soxhelt extraction was carried out and extracts were subjected to qualitative phytochemical analysis. Extract obtained by Soxhlation showed higher total phenolic and flavonoid contents.EBG showed DPPH and Nitric oxide scavenging activity indicating its strong antioxidant potential.On pylorus ligation-accumulated secretions and the related ulcers confirm gastric acid output to be the basic cause of gastric ulcers. Ethanol extract of leaves attenuated the gastric volume, free acidity, total acidity and ulcer index thus showing the anti-secretory mechanism.The results of the histopathological investigation of Barleria gibsoni leaves for antiulcer effects using pylorus ligation induced ulcer model in rats laid credence to traditional use of the plant leaves in ulcer treatment. The ethanol extract of leaves demonstrated increase in percentage preventive index compared to omeprazole respectively. From the present study results reveals the antiulcer activity of ethanol extract leaves which is comparable to that of Omeprazole. Abbreviations Used: EBG: Ethanol extract prepared from the leaves of B. gibsoni, ROS: Reactive Oxygen Species, DPPH: 2, 2-diphenyl-1-picrylhydrazyl, NO: Nitric Oxide, IC₅₀: The half maximal inhibitory concentration, m: mg, DNA: deoxyribonucleic acid, GAE: Gallic acid equivalence, AlCl₃: Aluminium chloride.

Anti-inflammatory Effects of Flavonoids on TNBS-induced Colitis of Rats

It has been shown that the extracts including eupatilin and quercetin-3-β-D-glucuronopyranoside had mucoprotective effects on the esophagus and stomach through their antioxidant activities. This study was designed to investigate the anti-inflammatory effect of these flavonoid compounds in an animal model of inflammatory bowel disease induced by 2,4,6-trinitrobenzene sulfonic acid. Experimental colitis was induced by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid. Extracts including eupatilin or quercetin-3-β-D-glucuronopyranoside were orally administered to animals 48, 24, and 1 h prior to the induction of colitis and then again 24 h later. The animals were sacrificed 48 h after by 2,4,6-trinitrobenzene sulfonic acid treatment and the macroscopic appearance of the colonic lesions was scored in a blinded manner on a scale of 1 to 10. The inflammatory response to colitis induction was assessed by measuring myeloperoxidase activity, nitric oxide production, tumor necrosis factor-α expression, total glutathione levels, and malondialdehyde concentrations in the colon. The results indicated that extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside dose-dependently improved the morphology of the lesions induced by 2,4,6-trinitrobenzene sulfonic acid and reduced the ulcer index accordingly. In addition, rats receiving extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside showed significantly decreased levels of mucosal myeloperoxidase activity, nitric oxide production, tumor necrosis factor-α expression, and malondialdehyde levels, and increased total glutathione levels. Extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside ameliorated the inflammatory response and colonic injury in acute colitis by decreasing oxidative stress and neutrophil activation. Extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside may inhibit acute colitis.

Animal models of gastrointestinal inflammation and cancer

Inflammation and cancer are the two major disorders in the gastrointestinal tract. They are causally related in their pathogenesis. It is important to study animal models' causal relationship and, in particular, to discover new therapeutic agents for such diseases. There are several criteria for these models in order to make them useful in better understanding the etiology and treatment of the said diseases in humans. In this regard, animal models should be similar as possible to human diseases and also be easy to produce and reproducible and also economic to allow a continuous replication in different laboratories. In this review, we summarize the various animal models for inflammatory and cancerous disorders in the upper and lower gastrointestinal tract. Experimental approaches are as simple as by giving a single oral dose of alcohol or other noxious agents or by injections of multiple dosages of ulcer inducing agents or by parenteral administration or in drinking water of carcinogens or by modifying the genetic makeups of animals to produce relatively long-term pathological changes in particular organs. With these methods they could induce consistent inflammatory responses or tumorigenesis in the gastrointestinal mucosa. These animal models are widely used in laboratories in understanding the pathogenesis as well as the mechanisms of action for therapeutic agents in the treatment of gastrointestinal inflammation and cancer.

The impact of smoking on neurosurgical outcomes

Cigarette smoking is a common health risk behavior among the general adult population, and is the leading preventable cause of morbidity and mortality in the US. The surgical literature shows that active tobacco smoking is a major risk factor for perioperative morbidity and complications, and that preoperative smoking cessation is an effective measure to lower these risks associated with active smoking. However, few studies have examined the effects of smoking and perioperative complications following neurosurgical procedures. The goal of this review was to highlight the scientific data that do exist regarding the impact of smoking on neurosurgical outcomes, to promote awareness of the need for further work in the specific neurosurgical context, and to suggest ways that neurosurgeons can promote smoking cessation in their patients and lead efforts nationally to emphasize the importance of preoperative smoking cessation. This review indicates that there is limited but good evidence that smoking is associated with higher rates of perioperative complications following neurosurgical intervention. Specific research is needed to understand the effects of smoking and perioperative complications. Neurosurgeons should encourage preoperative smoking cessation as part of their clinical practice to mitigate perioperative morbidity associated with active smoking.

Protective effect of sanguinarine against acetic acid-induced ulcerative colitis in mice

The quaternary ammonium salt, sanguinarine (SANG), is of great practical and research interest because of its pronounced, widespread physiological effects, which promote anti-microbial and anti-inflammatory responses in experimental animals. Although SANG is originally shown to possess anti-inflammatory properties and it has been used to treat various inflammatory diseases, its effects on ulcerative colitis have not been previously explored. The aim of the present study is to evaluate the effect of SANG on acetic acid-induced ulcerative colitis in mice. Experimental animals received SANG (1, 5 and 10 mg/kg, p.o.) and sulfasalazine (500 mg/kg, p.o.) for seven consecutive days after induction of colitis by intra-rectal acetic acid (5% v/v) administration. The colonic mucosal injury was assessed by clinical, macroscopic, biochemical and histopathological examinations. SANG treatment significantly decreased mortality rate, body weight loss, disease activity index (DAI), wet colon weight, macroscopic and histological score when compared to acetic acid-induced controls. In addition, administration of SANG effectively inhibited p65 NF-κB protein expression and MPO activity accumulation. The levels of TNF-α and IL-6 in the serum and colon tissue of mice with experimental colitis were decreased by SANG in a concentration-dependent manner in response to p65 NF-κB. The possible mechanism of protection on experimental colitis was that SANG could be through attenuating early steps of inflammation as well as decreasing the expression of NF-κB and subsequent pro-inflammatory cytokines production.

Protective effects of cathelicidin-encoding Lactococcus lactis in murine ulcerative colitis

BACKGROUND AND AIM

Intrarectal administration of mouse cathelin-related antimicrobial peptide (mCRAMP) reduced intestinal inflammation in mice. In the current study, we examined whether mCRAMP-transformed Lactococcus lactis given orally attained similar protective effects.

METHOD

mCRAMP was produced and secreted from the transformed L. lactis. Murine colitis was induced by ingestion of 3% dextran sulfate sodium (DSS) for 7 days. Eight or 10 log colony forming unit (cfu) L. lactis or the transformed strains with or without nisin induction were given orally as a parallel treatment with DSS. The body weight, fecal microbiota populations, clinical symptoms and histological examinations of colonic tissues were determined. Myeloperoxidase (MPO) activity and malondialdehyde (MDA) level were also evaluated to reflect the degree of inflammation. A prototype anti-inflammatory drug sulfasalazine was used as a reference drug to compare the efficacy and mechanisms of action for ulcerative colitis (UC).

RESULT

Compared with the control group with colitis, cathelicidin-transformed L. lactis could improve the clinical symptoms, maintain crypt integrity and preserve mucus content (P < 0.01). The number of apoptotic cells, MPO activity and MDA level were also significantly reduced (P < 0.05). The increases of fecal microbiota in colitis animals were markedly prevented (P < 0.001). Unlike mCRAMP-encoding L. lactis, effective doses of sulfasalazine only alleviated the clinical symptoms (P < 0.01) but not the mucosal damage in the colon.

CONCLUSION

mCRAMP-transformed L. lactis has been shown to produce mCRAMP, effectively preventing murine UC. Oral administration of this biological preparation is better than sulfasalazine for the treatment of UC.

Intrarectal administration of mCRAMP-encoding plasmid reverses exacerbated colitis in Cnlp(-/-) mice

Cathelicidin is a pleiotropic host defense peptide secreted by epithelial and immune cells. Whether endogenous cathelicidin is protective against ulcerative colitis, however, is unclear. Here we sought to delineate the role of endogenous murine cathelicidin (mCRAMP) and the therapeutic efficacy of intrarectal administration of mCRAMP-encoding plasmid in ulcerative colitis using dextran sulfate sodium (DSS)-challenged cathelicidin-knockout (Cnlp(-/-)) mice as a model. Cnlp(-/-) mice had more severe symptoms and mucosal disruption than the wild-type mice in response to DSS challenge. The tissue levels of interleukin-1β and tumor necrosis factor-α, myeloperoxidase activity and the number of apoptotic cells were increased in the colon of DSS-challenged Cnlp(-/-) mice. Moreover, mucus secretion and mucin gene expression were impaired in Cnlp(-/-) mice. All these abnormalities were reversed by the intrarectal administration of mCRAMP or mCRAMP-encoding plasmid. Taken together, endogenous cathelicidin may protect against ulcerative colitis through modulation of inflammation and mucus secretion.

The effect of smoking on intestinal inflammation: what can be learned from animal models?

Epidemiological evidence demonstrates that smoking is the most important environmental risk factor in Crohn's disease while it positively interferes with the disease course of ulcerative colitis. However, the underlying mechanisms through which smoking exerts this divergent effect and affects pathogenesis of inflammatory bowel disease are largely unknown. Animal smoke models are good models to investigate the impact of cigarette smoke on intestinal physiology and inflammation. They enable one to explore the interaction of smoke components and the gut on cellular and molecular level, clarifying how smoking interferes with normal gut function and with disease course in inflammatory conditions. This review describes the currently used animal models for studying the impact of cigarette smoke on the intestinal tract. We first discuss the different methods for simulation of smoking. Furthermore, we focus on the effect of smoke exposure on normal gut physiology and immunology, on experimental (entero)colitis, and on inflammation-induced neoplasia. Based on this current knowledge, a hypothesis is formulated about the mechanisms through which cigarette smoke interferes with the gut in normal and pathological conditions.

Anti-inflammatory effects of Pulvis Fellis Suis extract in mice with ulcerative colitis

ETHNOPHARMACOLOGICAL RELEVANCE

Pulvis Fellis Suis is used in folk medicines to treat intestinal diseases, acute pharyngitis, whooping cough and asthma in China. Although several reports indicate that Pulvis Fellis Suis display diverse biological activities, such as antibacterial, anti-inflammatory and anti-infusorian effects, its effects on ulcerative colitis have not been previously explored.

AIM OF THE STUDY

The purpose of the present study is to assess the anti-inflammatory effect of Pulvis Fellis Suis (PFS) extract in acute ulcerative colitis model induced by trinitrobenzene sulfonic acid (TNBS) in mice.

MATERIALS AND METHODS

Different doses of Pulvis Fellis Suis extract (100, 200 and 400mg/kg/day) and sulfasalazine (500mg/kg/day) were administered by gavage for 7days after the induction of colitis with TNBS. The efficacy of PFS was studied by macroscopical and histological scoring systems as well as myeloperoxidase (MPO) activity. Serum levels, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were assayed by enzyme-linked immunoassay. The expression of cyclooxygenase (COX)-2 in the colons was assessed by immunohistochemical analysis.

RESULTS

Treatment with PFS significantly attenuated macroscopic damage as compared with TNBS (P<0.01). Histological analysis showed that PFS improved the microscopic structure and preserved some areas of the colonic mucosa structure. In addition, administration of PFS effectively inhibited COX-2 protein expression and MPO activity accumulation. TNF-α and IL-6 levels were also diminished dose-dependently (P<0.05, P<0.01), and IL-6 level obtained had no significant results by small dose of PFS. All the effects of these parameters were comparable to that of the standard sulfasalazine, especially at the highest dose level.

CONCLUSIONS

We have shown for the first time that PFS has an anti-inflammatory effect in TNBS-induced ulcerative colitis which might be related to the reduction of up-regulated TNF-α and IL-6 production, and that it may have therapeutic value in the setting of inflammatory bowel disease (IBD).

Postsurgical recurrence of ileal Crohn's disease: an update on risk factors and intervention points to a central role for impaired host-microflora homeostasis

BACKGROUND

A pressing need exists to identify factors that predispose to recurrence after terminal ileal resection for Crohn's disease (CD) and to determine effective prophylactic strategies. This review presents an up-to-date summary of the literature in the field and points to a role for bacterial overproliferation in recurrence.

METHODS

The literature (Medline, Embase, and the Cochrane Library, 1971-2009) on ileal CD and postoperative recurrence was searched, and 528 relevant articles were identified and reviewed.

RESULTS

Smoking is a key independent risk factor for recurrence. NOD2/CARD15 polymorphisms and penetrating phenotype are associated with aggressive disease and higher reoperation rates. Age at diagnosis, disease duration, gender, and family history are inconsistent predictors of recurrence. Prophylactic 5-aminosalicylic acid therapy and nitromidazole antibiotics are beneficial. Combination therapies with immunosuppressants are also effective. Anti-TNFalpha-based regimens show benefit but the evidence base is small. Corticosteroid, interleukin-10, and probiotic therapies are not effective. Wider, stapled anastomotic configurations are associated with reduced recurrence rates. Strictureplasty and laparoscopic approaches have similar long-term recurrence rates to open resection techniques. Length of resection and presence of microscopic disease at resection margins do not influence recurrence. A lack of consensus exists regarding whether the presence of granulomas or plexitis affects outcome.

CONCLUSIONS

Current evidence points to defects in mucosal immunity and intestinal dysbiosis of either innate (NOD2/CARD15) or induced (smoking) origin in postoperative CD recurrence. Prophylactic strategies should aim to limit dysbiosis (antibiotics, side-to-side anastomoses) or prevent downstream chronic inflammatory sequelae (anti-inflammatory, immunosuppressive, and immunomodulatory therapy).

Protective effects of black cumin (Nigella sativa) oil on TNBS-induced experimental colitis in rats

BACKGROUND

The pathogenesis and treatment of ulcerative colitis remain poorly understood. The aim of the present study is to investigate the effects of black cumin (Nigella sativa) oil on rats with colitis.

METHODS

Experimental colitis was induced with 1 mL trinitrobenzene sulfonic acid (TNBS) in 40% ethanol by intracolonic administration with 8-cm-long cannula under ether anesthesia to rats in colitis group and colitis + black cumin oil group. Rats in the control group were given saline at the same volume by intracolonic administration. Black cumin oil (BCO, Origo "100% natural Black Cumin Seed Oil," Turkey) was given to colitis + black cumin oil group by oral administration during 3 days, 5 min after colitis induction. Saline was given to control and colitis groups at the same volume by oral administration. At the end of the experiment, macroscopic lesions were scored and the degree of oxidant damage was evaluated by colonic total protein, sialic acid, malondialdehyde, and glutathione levels, collagen content, and tissue factor, superoxide dismutase, and myeloperoxidase activities. Tissues were also examined by histological and cytological analysis. Proinflammatory cytokines [tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-6], lactate dehydrogenase activity, and triglyceride and cholesterol levels were analyzed in blood samples.

RESULTS

We found that black cumin oil decreased the proinflammatory cytokines, lactate dehydrogenase, triglyceride, and cholesterol, which were increased in colitis.

CONCLUSIONS

BCO, by preventing inflammatory status in the blood, partly protected colonic tissue against experimental ulcerative colitis.

Total alkaloids of Sophora alopecuroides increases the expression of CD4+ CD25+ Tregs and IL-10 in rats with experimental colitis

Previous studies have demonstrated that the total alkaloids of Sophora alopecuroides (TASA), which contains many different ingredients like sophocarpine, matrine, oxymatrine, sophoridine, sophoramine, aloperine and cytosine, were able to protect colon against ulcers caused by 2,4,6-trinitrobenze sulphonic acid (TNBS)/ethanol treated models. In order to elucidate the mechanisms by which TASA exerts its effect of anti-inflammation and immunoregulation on rats with colitis, DAI (disease activity index) and histological grading of colitis were evaluated in the animal model. Moreover, the expression of CD4(+)CD25(+) regulatory T cells (Tregs) and IL-10 in rats with experimental colitis were observed by FCM, ELISA and RT-PCR in this study. Results showed that TASA (15, 30 or 60 mg/kg/day) significantly up-regulated CD4(+)CD25(+)Tregs (P = 0.02, P = 0.02, P = 0.03) and IL-10 levels (ELISA: P = 0.03, P = 0.02, P = 0.00; RT-PCR: P = 0.04, P = 0.02, P = 0.01) respectively and decreased the DAI and histological grading of colitis in the peripheral blood (PB) and colon of rat colitis models (3.44 +/- 1.53, 4.25 +/- 1.27, 4.42 +/- 1.24 and 3.50 +/- 1.42, 4.05 +/- 1.32, 4.51 +/- 1.55 vs. 7.18 +/- 1.32 and 7.38 +/- 1.52, P < 0.05, P < 0.01, respectively). Most interestingly, a negative correlation was demonstrated between the expression of CD4(+)CD25(+) Tregs and DAI (Pearson r(PB) = -0.677, P < 0.01; Pearson r(COLON) = -0.663, P < 0.01, n = 60), or histological grading of colitis (Pearson r(PB) = -0.725, P < 0.01; Pearson r(COLON) = -0.623, P < 0.01, n = 60). Simultaneously, a positive correlation existed between CD4(+)CD25(+) Tregs and IL-10 cytokine (IL-10 mRNA) in the colon and PB of rats (Pearson r(PB) = 0.789, P < 0.01, n = 60; Pearson r(COLON) = 0.678, P < 0.01, n = 60). These results may explain to some extent the mechanisms of TASA on treating rats with experimental colitis.

Smoking and inflammatory bowel diseases: what in smoking alters the course?

Epidemiological studies provide strong evidence to confirm the correlation between cigarette smoking and inflammatory bowel diseases. This relationship is proved to be positive in Crohn's disease and negative in ulcerative colitis. What in smoking alters the course of inflammatory bowel diseases is still a mystery. Different smoking parts have different and may be opponent actions. Smoking has dual effects. Some of its activities are, sometimes, constructive as they are working in an antagonistic manner to the mechanism of the disease, such as reducing rectal blood flow and accordingly less recruitments of inflammatory mediators to the area of inflammation, enhancement of mucosal production, and consequently, strengthening the membranes, and inhibition of pro-inflammatory mediators' liberation and activity in subjects with ulcerative colitis. Yet the outcome of smoking actions may be affected by the existence of other cofactors. Odd factors, such as shortage of zinc in subjects with Crohn's disease, may facilitate liberation of pro-inflammatory mediators and their activities and accordingly exacerbates symptoms.

Interaction of cigarette smoking with cyclooxygenase-2 on ulcerative colitis-associated neoplasia in mice

The interactions of cigarette smoking with COX-2 on colitis and colitis-associated adenoma formation were studied. Mice were induced with colitis and exposed to cigarette smoke (CS) and/or SC236 (a COX-2 inhibitor). Results indicated that CS did not alter acute colonic inflammation. Addition of SC236 abolished the induction of proliferation and oxidative damage by colitis. Chronic SC236 treatment abolished the promoting effect of CS on colonic adenoma formation, via suppression of COX-2- and VEGF-mediated proliferation and angiogenesis, and reversed bcl-2-mediated inhibition of apoptosis by CS. To conclude, COX-2 inhibitor could be an implication on cancer prevention in smokers with chronic colitis.

Erdosteine prevents colonic inflammation through its antioxidant and free radical scavenging activities

After intracolonic administration of trinitrobenzene sulphonic acid (TNBS), Sprague-Dawley rats were treated orally either with saline or erdosteine (100 mg/kg per day), a sulfhydryl-containing antioxidant, for 3 days. On the 4th day, rats were decapitated and distal colon was removed for the macroscopic and microscopic damage scoring, for the measurement of malondialdehyde (MDA), glutathione (GSH) and collagen levels, myeloperoxidase (MPO) activity, luminol and lucigenin chemiluminescence (CL) and DNA fragmentation. Lactate dehydrogenase (LDH) activity, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, and antioxidant capacity were assayed in blood samples. Colitis caused significant increases in the colonic CL values, macroscopic and microscopic damage scores, MDA and collagen levels, MPO activity and DNA fragmentation, along with a significant decrease in tissue GSH level. Similarly, serum cytokines and LDH were elevated in the saline-treated colitis group as compared with the control group. On the other hand, erdosteine treatment reversed all these biochemical indices, and histopathologic alterations induced by TNBS, suggesting that erdosteine protects the colonic tissue via its radical scavenging and antioxidant activities.

PARP inhibition reduces acute colonic inflammation in rats

Poly(ADP-ribose) polymerases (PARP) comprise a family of enzymes which catalyse poly(ADP-ribosyl)ation of DNA-binding proteins. Multiple researches indicate the importance of PARP in promoting cell recruitment and thereby inducing organ injury in various forms of inflammation, such as colitis. We have evaluated the effects of two PARP inhibitors, nicotinamide and 1,5-dihydroxyisoquinoline, in acute colitis induced by trinitrobenzensulfonic acid (TNBS) in rats. Nicotinamide (20-40 mg/kg) and 1,5-dihydroxyisoquinoline (4-8 mg/kg) were administered 48, 24 and 1 h prior to the induction of colitis as well as 24 h later. 48 h after colitis induction the lesions were blindly scored and quantified as ulcer index. Histological study and colonic inflammation were assessed by gross appearance and myeloperoxidase (MPO) activity. Prostaglandin E2 (PGE2) synthesis and, cyclooxygenase-1 and cyclooxygenase-2 expressions by Western blotting and immunohistochemistry were also performed. Inflammation following TNBS induction was characterized by increased colonic wall thickness, oedema, diffuse inflammatory cells infiltration in the mucosa and necrosis. Furthermore, increased MPO activity, cyclooxygenase-2 expression and PGE2 synthesis were significantly augmented after TNBS instillation. On the contrary, treatment with 1,5-dihydroxyisoquinoline significantly reduced the degree of colon injury and also caused a substantial reduction in the rise in MPO activity, in the increase of staining for cyclooxygenase-2, as well as in the up-regulation of PGE2 caused by TNBS in the colon. Although nicotinamide significantly did not reduce macroscopic damage, it decreased both MPO activity and PGE2 colonic levels. In conclusion, we demonstrated that PARP inhibition can exert beneficial effects in experimental colitis and may, therefore, be useful in the treatment of ulcerative colitis.

Smoking habit and load influence age at diagnosis and disease extent in ulcerative colitis

INTRODUCTION

Cigarette smoking affects susceptibility to ulcerative colitis (UC), but its effects on age at diagnosis, disease extent, and need for surgery are less well defined. We examined these parameters in a detailed retrospective analysis of a large cohort of well-characterized UC patients.

METHODS

499 UC patients (254 male, median age 34.3 yr) were studied. Data were collected on smoking habits, smoking load (pack-years), age at recruitment, age at diagnosis, surgery, and disease extent. Colonoscopic and histological data at both diagnosis and follow-up (median follow-up time 4.6 yr) were available on 349 patients.

RESULTS

Ex-smokers were older at diagnosis than current or nonsmokers, (46.5 yr vs 31.1 or 29.4 yr, respectively, P < 0.001). Before diagnosis, ex-smokers had a higher smoking load than current smokers (13.0 vs 6.94 pack-years, P < 0.001). A Cox model for age at diagnosis, with smoking as a time-dependent covariate, showed that at any age, ex-smokers were significantly more likely to develop UC than current smokers (hazard ratio 1.8, 95% CI 1.41-2.44, P < 0.001). For current smokers at latest colonoscopy, those with extensive disease were the lightest smokers (median 0.320 pack-years), whereas those with healthy colons were the heaviest smokers (median 9.18 pack-years, P= 0.006). At 5 yr, regression of extensive disease was more frequent in current than ex-smokers or nonsmokers (30% current smokers vs 8% nonsmokers and 5% ex-smokers, chi(2)= 30.4, P < 0.001) but these differences were not maintained over a longer time period.

CONCLUSIONS

Smoking habit influences the age at diagnosis and changes in disease extent in UC. Mechanisms are likely to be complex and require further investigation.

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.

Plant originated glycoprotein has anti-oxidative and anti-inflammatory effects on dextran sulfate sodium-induced colitis in mouse

We investigated the preventive effect of glycoprotein (27 kDa) isolated from Gardenia jasminoides Ellis (GJE) fruits on colitis in dextran sulfate sodium (DSS, 3%)-induced A/J mice which were administrated orally for 7 days. Anti-inflammatory activity of GJE glycoprotein was assessed by neutrophil infiltration and colonic lipid peroxidation, and determined by myeloperoxidase (MPO) activity and levels of thiobarbituric acid reactive substances (TBARS), respectively in DSS treatment system. The activities of antioxidative enzymes [catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx)], activation of inflammation related mediators (iNOS, COX-2, and NF-kappaB), and production of nitric oxide (NO) and reactive oxygen species (ROS) were also measured. The results of this study showed that GJE glycoprotein (80 microg/ml) has a scavenging property to inhibit the intracellular ROS production in RAW 264.7 cells and that GJE glycoprotein (80 mg/kg BW) significantly suppressed the increase in the MPO activity, TBARS level, and NO production, inflammation related mediators [iNOS, COX-2, and NF-kappaB (p50)] activity in DSS-induced mice. Interestingly, the activities of CAT, SOD, and GPx were gradually augmented after a supplement of GJE glycoprotein. Therefore, we suggest that GJE glycoprotein is preventive and therapeutic agent for the ulcerative colitis.

Effects of exopolysaccharide-producing probiotic strains on experimental colitis in rats

PURPOSE

Inflammatory bowel disease is suggested to result from a dysregulated immune response toward intestinal microflora, which may be restored by probiotic therapy based on the concept of healthy microflora. Ideal probiotic bacteria may be beneficial in inflammatory bowel disease; however, the mechanism of action and the clinical efficacy of probiotic usage are still unclear. In the present study, the effect of exopolysaccharide producing probiotics was evaluated on an experimental colitis model in rats.

METHODS

Colitis was induced by intracolonic administration of acetic acid. Then, rats were treated daily with two probiotic strains, Lactobacillus delbrueckii subsp. bulgaricus B3 strain (exopolysaccharide of 211 mg/l: high-EPS group) or Lactobacillus delbrueckii subsp. bulgaricus A13 strain (EPS of 27 mg/l: low-EPS group), which were given into the stomach. The non-colitis-fed control group was only treated with high-exopolysaccharide strain. The model-control and control groups were treated only with tap water. Rats were killed after a seven-day treatment period. Disease activity was quantified by use of histologic scores and colonic myeloperoxidase activity, which is a marker of neutrophil infiltration during inflammation.

RESULTS

The enhanced inflammatory response was accompanied by a higher level of myeloperoxidase activity in the colitis group. Histologic scores of colonic damage and myeloperoxidase activity were lower in both probiotic-treated groups compared with those of the colitis control group (P<0.001), although the mentioned scores improved significantly more in the high-EPS group than in the low-EPS group (P<0.001).

CONCLUSIONS

Exopolysaccharide-producing probiotics significantly attenuate experimental colitis, which may be mediated by exopolysaccharide in a dose-dependent manner. Therefore, exopolysaccharide-producing probiotics may be a promising therapeutic role in inflammatory bowel disease.

Inhibitory effects of histamine H4 receptor antagonists on experimental colitis in the rat

The histamine H(4) receptor is a G-protein coupled receptor with little homology to the pro-inflammatory histamine H(1) receptor, expressed on cells of the immune system with hematopoietic lineage such as eosinophils and mast cells. The effects of the recently described highly selective histamine H(4) receptor antagonists JNJ 10191584 and JNJ 7777120 have now been investigated on the acute colitis provoked by trinitrobenzene sulphonic acid over 3 days in the rat. Treatment with JNJ 10191584 (10-100 mg/kg p.o., b.i.d.) caused a dose-dependent reduction in macroscopic damage, inhibition of the TNBS-provoked elevation of both colonic myeloperoxidase and tumour necrosis factor-alpha (TNF-alpha), and a reduction in the histologically assessed increase in mucosal and submucosal thickness and neutrophil infiltration. JNJ 7777120 (100 mg/kg p.o., b.i.d.) likewise reduced the macroscopic injury and the increases in colonic myeloperoxidase and TNF-alpha levels. These findings indicate a pro-inflammatory role for the histamine H(4) receptor in this model and suggest a novel pharmacological approach to the treatment of colitis.

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.

The diverse actions of nicotine and different extracted fractions from tobacco smoke against hapten-induced colitis in rats

The etiology of ulcerative colitis (UC) remains unknown, although the risk of developing UC is apparently higher in non-smokers and ex-smokers. We have demonstrated in a colitis animal model that exposure to tobacco smoke could attenuate UC pathogenesis. The present study aimed to investigate and compare between the modes of action of nicotine and different fractions of tobacco smoke extract in the development of experimental colitis. The hapten 2,4-dinitrobenzene sulfonic acid (DNBS) was used to induce colitis in Sprague-Dawley rats. Results indicated that both tobacco smoke exposure and subcutaneous nicotine differentially reduced colonic lesion size, myeloperoxidase (MPO) activity, luminol-amplified free radical generation, and leukotriene B4 formation in the inflamed colon of colitis animals. These phenomena were accompanied by the downregulation of colonic interleukin (IL)-1beta and monocyte chemoattractant protein (MCP)-1 protein expression. By treating the colitis animals with various tobacco extracts, we further discovered that ethanol extract from filtered tobacco smoke could attenuate DNBS-evoked colonic damage and the elevated MPO activity, while at the same time it downregulated colonic IL-1beta and MCP-1 protein expression. In contrast, the highest dose of the chloroform extract from the cigarette filter caused aggravating effects and overexpression of the pro-inflammatory cytokines and chemokines. These data suggest that effective attenuation of DNBS-induced colitis by tobacco smoke could be due to its nicotine content and possibly other flavonoid components found in the ethanol smoke extract.

Association Between 5-Lipoxygenase Expression and Plaque Instability in Humans

OBJECTIVE

The participation of 5-lipoxygenase (5-LO) in the development of atherosclerosis has been suggested by recent studies. However, a role for 5-LO as a modulator of atherosclerotic plaque instability has not been previously reported in humans. Thus, the aims of this study was to analyze the expression of 5-LO in human carotid plaques and to investigate the mechanism by which this enzyme could lead to plaque instability and rupture.

METHODS AND RESULTS

We obtained atherosclerotic plaques from 60 patients undergoing carotid endarterectomy. We divided the plaques into symptomatic and symptomatic according to clinical evidence of plaque instability. Clinical evidence of plaque instability was provided by the assessment of recent ischemic symptoms attributable to the stenosis and by the presence of ipsilateral cerebral lesion(s) determined by computed tomography. Plaques were analyzed for CD68+ macrophages, CD3+ T cells, alpha-actin+ smooth muscle cells, 5-LO, cyclooxygenase 2, matrix metalloproteinase (MMP)-2, and MMP-9 by immunohistochemical, immunoblotting, and densitometric analyses. MMP activity was assessed by zymography. Leukotriene (LT) B4 and collagen were quantified by ELISA and Sirius red polarization, respectively. The percentage of macrophage-rich and T-cell-rich areas was larger in symptomatic compared with asymptomatic patients (25+/-6% versus 8+/-4%, P<0.0001, and 74+/-17 versus 18+/-4 cell/mm2, P<0.003). 5-LO expression was higher in symptomatic compared with asymptomatic plaques (24+/-4% versus 6+/-3%, P<0.0001) and was associated with increased MMP-2 and MMP-9 expression (27+/-4% versus 7+/-3%, P<0.0001, and 29+/-5% versus 8+/-2%, P<0.0001) and activity and with decreased collagen content (6.9+/-2.4% versus 17.8+/-3.1%, P<0.01). Immunofluorescence showed that 5-LO and MMPs colocalize in activated macrophages. Notably, higher 5-LO in symptomatic plaques correlated with increased LTB4 production (18.15+/-3.56 versus 11.27+/-3.04 ng/g tissue, P<0.0001).

CONCLUSIONS

The expression of 5-LO is elevated in symptomatic compared with asymptomatic plaques and is associated with acute ischemic syndromes, possibly through the generation of LTB4, subsequent MMP biosynthesis, and plaque rupture.

The effects of selective cyclooxygenase-2 inhibitors, celecoxib and rofecoxib, on experimental colitis induced by acetic acid in rats

Several mediators may be involved in the pathogenesis of inflammatory bowel disease, as well as in experimental colitis. The present work was conducted to investigate the effects of the two selective cyclooxygenase-2 inhibitors, celecoxib and rofecoxib, on experimentally induced colitis in rats. Rectal instillation of acetic acid was used to induce the colitis. Acetic acid treatment caused haemorrhagic diarrhoea and weight loss in rats. Celecoxib (5 mg/kg) or rofecoxib (2.5 mg/kg), when given twice daily by the oral route, reduced the degree of haemorrhagic diarrhoea and the weight loss produced. In addition, they produced a significant reduction in the degree of colonic injury, the rise in myeloperoxidase (MPO) levels, total nitric oxide synthetase (NOS) activity, platelet-activating factor (PAF), histamine levels and prostaglandin E2 levels. In contrast, there was a significant increase in the levels of reduced glutathione (GSH). Thus, the findings of the present study provide evidence that selective cyclooxygenase-2 inhibitors may be beneficial in patients with inflammatory bowel disease.

Inflammatory bowel disease and smoking: a review of epidemiology, pathophysiology, and therapeutic implications

The relationship between smoking behavior and inflammatory bowel disease (IBD) is complex. While Crohn's disease (CD) is associated with smoking and smoking has detrimental effects on the clinical course of the disease, ulcerative colitis (UC) is largely a disease of nonsmokers and former smokers. Furthermore, cigarette smoking may even result in a beneficial influence on the course of ulcerative colitis. The potential mechanisms involved in this dual relationship include changes in humoral and cellular immunity, cytokine and eicosanoid levels, gut motility, permeability, and blood flow, colonic mucus, and oxygen free radicals. Nicotine is assumed to be the active moiety. The differential therapeutic consequences comprise the cessation of smoking in CD and, so far, clinical trials using nicotine in different forms of application for UC. In this article, we review the relationship between cigarette smoking and IBD, considering epidemiological, pathogenetic, and clinical aspects.

A new flavonoid derivative, dosmalfate, attenuates the development of dextran sulphate sodium-induced colitis in mice

In this study, we have evaluated the efficacy of dosmalfate, a new flavonoid derivative compound, for the prevention and treatment of experimental colitis. To induce colitis, BALB/c mice received 5% dextran sulphate sodium (DSS) in their drinking water continuously for 7 days. Colitis was quantified by a clinical damage score, colon length, weight loss, stool consistency and rectal bleeding. Inflammatory response was assessed by neutrophil infiltration, determined by histology and myeloperoxidase (MPO) activity. Interleukin (IL)-1 beta, prostaglandins (PG)E(2) and (PG)D(2) concentrations in colonic tissue, histological and histochemical analysis of the lesions were also measured. Dosmalfate (400-800 mg/kg body weight, p.o.) ameliorated severe colitis reduced the degree of inflammation through reduction of neutrophil infiltration and IL-1 beta levels. (PG)E(2) and (PG)D(2) synthesis were significantly reduced in colitis control group and treatment with dosmalfate abolished the decrease in PG synthesis in colon mucosa. We conclude that dosmalfate is protective in acute DSS-induced colitis. The beneficial effects seem to be related to a decrease of neutrophil infiltration, absence of up-regulation of IL-1 beta and increase of PG production in colon mucosa.

Ameliorating effects of the immunomodulator 3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole in an experimental model of colitis in the rat

The therapeutic efficacy of the immunomodulator 3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole (ST1959) in colonic inflammation was assessed in rats. One hour following colonic instillation of ethanolic 2,4,6-trinitrobenzene sulphonic acid (TNBS), intracolonic administration of 0.4 mg/kg ST1959 was started and continued once daily for 1 or 2 weeks. Daily administration of ST1959 for 1 week significantly reduced macroscopic and histological damage, myeloperoxidase activity, and colonic tissue levels of tumour necrosis factor-alpha and interferon-gamma. ST1959 did not affect interleukin-12 levels but significantly enhanced the production of interleukin-10 (sixfold increase). Two weeks of ST1959 treatment reduced the thickness of the colonic wall and myeloperoxidase activity to the same extent, and the histologic appearance of the mucosa was largely restored. The ameliorating effects seem to be ascribable to an impairment of both neutrophil infiltration/activation and tumour necrosis factor-alpha and interferon-gamma production, possibly consequent to the observed increase in the colonic tissue levels of the potent anti-inflammatory cytokine interleukin-10. Similar results were observed with the reference drug 5-aminosalycilic acid.

Cigarette smoke exposure increases ulcerative colitis-associated colonic adenoma formation in mice

Both chronic ulcerative colitis and smoking are associated with colorectal cancer in humans. In the present study, we investigated the effects of cigarette smoke (CS) exposure on inflammation-associated tumorigenesis in the mouse colon. Male balb/c mice were allocated into six groups: control, CS (2%), CS (4%), colitis, colitis + CS (2%) and colitis + CS (4%). They were given water or 3% dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis, with or without 1 h daily exposure to 2 or 4% CS. They were then allowed to drink water for 14 days. The cycle of 7 day DSS +/- CS/14 day H2O treatments were repeated twice. Mice were killed immediately or 1 month after the three cycles of treatments. Results indicated colonic adenoma was only found in the colitis group (one out of 11), Colitis + CS (2%) group (seven out of 12) and colitis + CS (4%) group (four out of five) 1 month after three cycles of DSS and/or CS treatment. CS exposure dose-dependently increased adenoma formation in mice with inflamed mucosa. CS exposure plus colitis was strongly associated with a high incidence of dysplasia (P < 0.01) and adenocarcinoma formation (P < 0.01) compared with induction of colitis alone. Colitis induced cell proliferation and apoptosis in colonic tissues. Cigarette smoking significantly attenuated the apoptotic effect by DSS probably via the induction of anti-apoptotic protein bcl-2. The ratio of apoptosis over proliferation was also significantly lower in the colitis + CS groups. Vascular endothelial growth factor and angiogenesis in the colon were also increased by cigarette smoking in animals with colitis. In conclusion, CS promotes inflammation-associated adenoma/adenocarcinoma formation in the mouse colon in a dose-dependent manner. This tumor development is associated with the inhibition of cellular apoptosis and supported by increased angiogenesis.

Cholinergic pathways modulate experimental dinitrobenzene sulfonic acid colitis in rats

Recent studies have suggested that neuroimmune interactions modulate intestinal mucosal immune responses. In the current study, we examined the role of cholinergic pathways in modulating the severity of acute dinitrobenzene sulfonic acid colitis, using pharmacological agents to suppress acetylcholinesterase in Sprague-Dawley rats, and evaluating the colitis in the cholinergic hyperresponsive Flinder's sensitive line rats and their control counterparts, the Flinder's resistant line. Colitis was induced by intrarectal dinitrobenzene sulfonic acid (80 mg x ml(-1) in 50% ethanol); controls received intrarectal saline. Sprague-Dawley rats received an acetylcholinesterase inhibitor, physostigmine (50 microg x kg(-1) s.c.) or neostigmine (50 microg x kg(-1) s.c.), 30 min prior to intrarectal dinitrobenzene sulfonic acid; controls received saline vehicle. On day 5, the macroscopic damage score, myeloperoxidase activity (an estimate of granulocyte infiltration) and smooth muscle thickness were evaluated in the inflamed colonic segment. Significant increases in macroscopic damage score and colonic smooth muscle thickness were observed in Sprague-Dawley and Flinder's Resistant Line rats on day 5 following intrarectal dinitrobenzene sulfonic acid compared to saline controls. Increased myeloperoxidase activity was also observed in dinitrobenzene sulfonic acid-treated Sprague-Dawley rats and Flinder's Resistant Line rats. In contrast, Flinder's Sensitive Line rats failed to demonstrate a significant rise in macroscopic damage, smooth muscle layer thickness, or myeloperoxidase activity on day 5 following intrarectal dinitrobenzene sulfonic acid when compared to saline-treated Flinder's Sensitive Line controls. Neostigmine and physostigmine treatment prior to intrarectal dinitrobenzene sulfonic acid significantly attenuated macroscopic damage score, myeloperoxidase activity and smooth muscle thickness on day 5 compared to colitic Sprague-Dawley controls. Significantly greater reductions in myeloperoxidase activity were observed with physostigmine vs. neostigmine pretreatment. These data suggest that cholinergic pathways modulate the acute colonic inflammatory response associated with the dinitrobenzene sulfonic acid model, with central pathways exerting a greater protective effect relative to peripheral pathways. Further studies are required to determine the contributions of sites in the nervous system and neuro-effector junctions.

In vivo influence of nicotine on human basal and NSAID-induced gut barrier function

BACKGROUND

Smoking reduces the non-steroidal anti-inflammatory drug (NSAID)-induced small intestinal permeability increase in healthy people. It also affects inflammatory bowel disease that is associated with a disturbed gut barrier function. To assess the role of nicotine on barrier function, its influence on basal and NSAID-induced intestinal permeability was studied in healthy volunteers.

METHODS

Thirty-one healthy non-smoker subjects performed permeability tests with 51Cr-EDTA and sugar markers (sucrose, lactulose, mannitol, sucralose) before and during 2 weeks of nicotine patch application, and with and without indomethacin intake, respectively. Since smoking has been described as affecting motility, transit measurements were also done with the sodium[13C]-octanoate and lactose-[13C]-ureide breath tests before and during nicotine exposure. Correlations between permeability markers were checked and the influence of gastrointestinal transit was assessed.

RESULTS

Nicotine did not affect barrier function in vivo, nor gastric emptying, small-bowel transit time or orocaecal transit. 51Cr-EDTA and lactulose correlated in basal 0-6 h permeability testing (r = 0.529, P < 0.0001), as did 6-24 h excretion of 51Cr-EDTA and sucralose (r = 0.474, P < 0.001); 97% and 90% of the subjects had a permeability increase after indomethacin intake for 0-6 h and 6-24 h excretion of Cr-EDTA, respectively. This population proportion is 63% for lactulose/mannitol and 83% for sucralose.

CONCLUSIONS

Short-term exposure to nicotine does not alter normal basal or NSAID-induced gut barrier function or transit. 51Cr-EDTA and the respective sugar markers correlate well in in vivo permeability testing in healthy humans. The radioactive test detects more NSAID-induced permeability increase than does the lactulose/mannitol ratio permeability test.

Effects of dosmalfate, a new cytoprotective agent, on acute and chronic trinitrobenzene sulphonic acid-induced colitis in rats

Activated neutrophils and proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) are clearly involved in the pathogenesis of bowel disease. Increased expression of epidermal growth factor-receptor (EGF receptor) has been reported for the colon mucosa surrounding areas of ulceration, suggesting a pivotal role in mucosal defence and repair. In this study, we examined the effects of dosmalfate, a new flavonoid derivative compound (diosmin heptakis) with antioxidant and cytoprotective properties, on acute and chronic experimental trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. The inflammation response was assessed by neutrophil infiltration as evaluated by histology and myeloperoxidase activity. Mucosal TNF-alpha production and histological analysis of the lesions was also carried out. In addition, we studied the expression of the EGF receptor inmunohistochemically during the healing of TNBS-induced chronic colitis. A 2-day treatment with 400 or 800 mg/kg of dosmalfate ameliorated the colon damage score and the incidence of adhesions. It also significantly (P<0.05) decreased myeloperoxidase activity and colonic mucosal production of TNF-alpha. Chronic treatment (14 days) with 800 mg/kg/day of dosmalfate also had significant protective effects on TNBS-induced colitis which were reflected by significant attenuation (P<0.05) of the damage score while the inflammatory indicators were not improved. The chronic beneficial effect of dosmalfate was apparently related to the enhancement of EGF receptor expression. These findings confirm the protective effects of dosmalfate in acute and chronic experimental colitis.

Neutrophil capture by selectins on endothelial cells exposed to cigarette smoke

We used a novel perfusion system to expose cultured human umbilical vein endothelial cells (HUVEC) to water-soluble components of cigarette smoke and study subsequent adhesion of flowing neutrophils. Neutrophils did not bind to HUVEC immediately after it had been exposed to cigarette smoke, but many adhered 90-150 min after exposure. The effect was reduced if the exposed medium was made serum-free, but this reduction was partially reversed if low density lipoprotein was added. Treatment of smoke-exposed HUVEC with antibodies against E-selectin or P-selectin reduced adhesion by approximately 50% or 75%, respectively; a combination of both antibodies essentially abolished adhesion. Enzyme-linked immunosorbent assay confirmed that exposure to smoke caused HUVEC to upregulate surface expression of E- and P-selectin. Thus, water-soluble constituent(s) of cigarette smoke cause efficient selectin-mediated capture of flowing neutrophils. This pro-inflammatory response may contribute to pathology associated with smoking, especially in tissues remote from the lung.

Chronic nicotine administration differentially alters jejunal and colonic inflammation in interleukin-10 deficient mice

BACKGROUND

Cigarette smoking alters the course of inflammatory bowel disease, is associated with protection against ulcerative colitis, but aggravates or has no effect on Crohn's disease. While the aetiology of this discrepancy remains unclear, differences between location of involvement in ulcerative colitis and Crohn's disease have not been examined in these studies.

AIM

To examine the effects of nicotine administration on the course of jejunitis and colitis in interleukin-10 deficient mice.

METHODS

Male C57/BL10 IL-10 -/- and wild type mice were given nicotine (12.5 microg/ml) in their drinking water at age 12-14 weeks when they had developed clinical signs of inflammatory bowel disease. Gender and age matched control mice received tap water alone. All mice were killed after 2 weeks of treatment. Whole tissue sections of jejunum, proximal and distal colon were separated and examined by macroscopic and histological score. Northern blots were examined for somatostatin, intestinal trefoil factor and mucin-2.

RESULTS

At 14-16 weeks, when the mice were killed, IL-10 -/- untreated control mice developed jejunitis (macroscopic score 1.4 +/- 0.5, microscopic score 2.0 +/- 0.2) and colitis (2.0 +/- 0.2 and 5.9 +/- 0.9, respectively). IL-10 -/- mice treated for 2 weeks with nicotine had significantly reduced colonic scores (1.4 +/- 0.6 and 2.2 +/- 0.15, respectively). In contrast, the jejunum was more severely damaged (2.6 +/- 0.4 and 4.0 +/- 0.3; P = 0.01, respectively). Nicotine significantly increased both somatostatin and intestinal trefoil factor mRNA expression in the colon but not in the jejunum; no effect was noted on mucin-2 or beta-actin mRNA expression.

CONCLUSIONS

(1) Two weeks of nicotine administration leads to contrasting effects on jejunal and colonic inflammation in IL-10 -/- mice. (2) Nicotine ameliorated inflammation in the colon, which was associated with enhanced expression of two protective peptides.

Protective role of heme oxygenase-1 on trinitrobenzene sulfonic acid-induced colitis in rats

Preliminary studies showed that the inducible form of heme oxygenase (HO-1) was induced and played a protective role in the process of inflammation. The present study investigated the possible role of HO-1 in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. We measured HO-1 activity in TNBS-induced colitis in rats and analyzed the severity of colitis along with altered HO activity by assessing lesion area and myeloperoxidase activity. HO-1 mRNA and protein expressions were determined at different time points after TNBS induction. Free radical production and inducible nitric oxide synthase (iNOS), which participate in oxidative injury, were also assayed. HO activity and HO-1 gene expression increased markedly after TNBS induction. Administration with tin mesoporphyrin (SnMP), a HO inhibitor, potentiated the colonic damage along with a reduction in HO-1 activity. Furthermore, the reduction of HO-1 expression by SnMP also enhanced reactive oxygen species and iNOS expression, both of which were dramatically increased after the TNBS enema. L-Arginine pretreatment further aggravated the injurious action of SnMP. Our results indicate that HO-1 plays a protective role in the colonic damage induced by the TNBS enema, and the preventive effects probably result from decreased free radical production and inhibition of iNOS expression in colonic tissues.

Inhibitory effects of methanol extract of Cyperus rotundus rhizomes on nitric oxide and superoxide productions by murine macrophage cell line, RAW 264.7 cells

The rhizomes of Cyperus rotundus (C. rotundus) have been used in oriental traditional medicines for the treatment of stomach and bowel disorders, and inflammatory diseases. Nitric oxide (NO) and superoxide (O2-) are important mediators in the pathogenesis of inflammatory diseases. This study was undertaken to address whether the metanol (MeOH) extract of rhizomes of C. rotundus could modulate NO and O2- productions by murine macrophage cell line, RAW 264.7 cells. The MeOH extract of rhizomes of C. rotundus showed the inhibition of NO production in a dose-dependent manner by RAW 264.7 cells stimulated with interferon-gamma plus lipopolysaccharide. The inhibition of NO production by the extract was due to the suppression of iNOS protein, as well as iNOS mRNA expression, determined by Western and Northern blotting analyses, respectively. In addition, the MeOH extract suppressed the production of O2- by phorbol ester-stimulated RAW 264.7 cells in dose- and time-dependent manners. Collectively, these results suggest that the MeOH extract of rhizomes of C. rotundus could be developed as anti-inflammatory candidate for the treatment of inflammatory diseases mediated by overproduction of NO and O2-.

Increased urinary nitrite, a marker of nitric oxide, in active inflammatory bowel disease

BACKGROUND

Nitric oxide (NO) production is increased in inflammatory bowel disease (IBD), and measurement of NO metabolites may be useful for monitoring disease activity.

AIMS AND OBJECTIVES

To characterise urinary nitrite levels, a stable metabolite of NO, in IBD and to evaluate its potential as a marker of disease activity.

METHODS

Twelve-hour urinary nitrites were measured by the microplate assay method in 46 patients with IBD (active; n = 32). Urinary samples from 16 healthy individuals served as controls.

RESULTS

Increased levels of urinary nitrites were found in patients with active IBD compared with those with inactive IBD. Twenty-eight out of 32 patients (87.5%) with active IBD had detectable levels of nitrite in their urine as compared with 2/14 (14.3%) patients with inactive IBD. None of the 16 healthy controls had detectable urinary nitrite. Twelve-hour urinary nitrite in active compared with inactive IBD: 5 0.7 versus 0.1+/-0.04 micromol (P < 0.05). There was good correlation between urinary nitrite and some markers of disease activity in IBD such as C-reactive protein and microalbuminuria but not with erythrocyte sedimentation rate.

CONCLUSIONS

Increased levels of nitrite were detected in urine of patients with active IBD, consistent with increased NO synthesis. This simple assay may be exploited as a potential marker of disease activity in IBD.

Protective role of cyclooxygenase inhibitors in the adverse action of passive cigarette smoking on the initiation of experimental colitis in rats

Clinical and experimental findings had indicated that cigarette smoke exposure, and cyclooxygenase-2, are strongly associated with inflammatory bowel disease. The present study aimed to evaluate the role of cyclooxygenase-2 in the pathogenesis of experimental inflammatory bowel disease as well as in the adverse action of cigarette-smoke exposure. Rats were pretreated with different cyclooxygenase-2 inhibitors (indomethacin, nimesulide, or SC-236 (4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide)) along with cigarette-smoke exposure before 2,4,6-trinitrobenzenesulfonic acid-enema. Results indicated that pretreatment with cyclooxygenase-2 inhibitors not only protected against 2,4,6-trinitrobenzenesulfonic acid-induced inflammatory bowel disease, but also attenuated the potentiating effect of cigarette-smoke exposure on colonic damage. Furthermore, the colonic cyclooxygenase-2 protein and mRNA expression was markedly induced by 2,4,6-trinitrobenzenesulfonic acid-enema, and it was potentiated further by cigarette-smoke exposure, while the cyclooxygenase-1 expression was not changed. The present study suggests that the highly induced cyclooxygenase-2 expression not only plays a pathogenic role in 2,4,6-trinitrobenzenesulfonic acid-induced inflammatory bowel disease, but also contributes to the adverse action of cigarette-smoke exposure on this disorder.