Anti-inflammatory and anti-oxidant activities of olmesartan medoxomil ameliorate experimental colitis in rats

Inflammatory bowel disease: exploring gut pathophysiology for novel therapeutic targets

Ulcerative colitis and Crohn's disease are the 2 major phenotypes of inflammatory bowel disease (IBD), which are influenced by a complex interplay of immunological and genetic elements, though the precise etiology still remains unknown. With IBD developing into a globally prevailing disease, there is a need to explore new targets and a thorough understanding of the pathophysiological differences between the healthy and diseased gut could unearth new therapeutic opportunities. In this review, we provide an overview of the major aspects of IBD pathogenesis and thereafter present a comprehensive analysis of the gut pathophysiology leading to a discussion on some of the most promising targets and biologic therapies currently being explored. These include various gut proteins (CXCL-10, GATA-3, NKG2D, CD98, microRNAs), immune cells recruited to the gut (mast cells, eosinophils, toll-like receptors 2, 4), dysregulated proinflammatory cytokines (interleukin-6, -13, -18, -21), and commensal microbiota (probiotics and fecal microbiota transplantation). We also evaluate some of the emerging nonconventional therapies being explored in IBD treatment focusing on the latest developments in stem cell research, oral targeting of the gut-associated lymphoid tissue, novel anti-inflammatory signaling pathway targeting, adenosine deaminase inhibition, and the beneficial effects of antioxidant and nutraceutical therapies. In addition, we highlight the growth of biologics and their targets in IBD by providing information on the preclinical and clinical development of over 60 biopharmaceuticals representing the state of the art in ulcerative colitis and Crohn's disease drug development.

An Hydroalcoholic Chamomile Extract Modulates Inflammatory and Immune Response in HT29 Cells and Isolated Rat Colon

Inflammatory bowel diseases (IBDs) are chronic disorders characterized by disruption and ulceration of the colonic mucosa or of any part of the digestive tract (Crohn's disease). Antioxidant/anti-inflammatory herbal extract supplementation could represent an innovative approach to contrast IBDs. Clinical trials demonstrated the efficacy of natural formulas, containing chamomile, in patients with gastrointestinal disorders. This is consistent, albeit in part, with the antioxidant and anti-inflammatory properties of chamomile. The aim of the present study was to explore the possible protective role of a chamomile extract, on human colorectal adenocarcinoma HT29 cell, and rat colon specimens treated with lipopolysaccharide (LPS) to induce an inflammatory stimulus, a well established model of acute ulcerative colitis. In this context, the activities of different biomarkers of inflammation and lipid peroxidation such as ROS, myeloperoxidase (MPO), serotonin (5-HT), prostaglandin (PG)E2 , 8-iso-prostaglandin (8-iso-PG)F2α , NF-kB, tumor necrosis factor (TNF)α and interleukin (IL)-6 were assessed. We found that chamomile extract was as effective as sulfasalazine (2 mg/ml) in reducing the production of MPO, 5-HT, IL-6, NF-kB, TNFα, PGE2 and 8-iso-PGF2α , after inflammatory stimulus. The observed modulatory effects support a rationale use of chamomile supplementation as a promising pharmacological tool for the prevention and management of ulcerative colitis in humans. Copyright © 2016 John Wiley & Sons, Ltd.

Oroxyloside prevents dextran sulfate sodium-induced experimental colitis in mice by inhibiting NF-κB pathway through PPARγ activation

Oroxyloside, as a metabolite of oroxylin A, may harbor various beneficial bioactivities which have rarely been reported in the previous studies. Here we established the dextran sulfate sodium (DSS)-induced experimental colitis and evaluated the anti-inflammatory effect of oroxyloside in vivo. As a result, oroxyloside attenuated DSS-induced body weight loss, colon length shortening and colonic pathological damage. Furthermore, oroxyloside inhibited inflammatory cell infiltration and decreased myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activities as well. The production of pro-inflammatory cytokines in serum and colon was also significantly reduced by oroxyloside. We unraveled the underlying mechanisms that oroxyloside inhibited NF-κB pathway by activating Peroxisome Proliferator-Activated Receptor γ (PPARγ) to attenuate DSS-induced colitis. Moreover, we investigated the anti-inflammatory effect and mechanisms of oroxyloside in the mouse macrophage cell line RAW264.7 and bone marrow derived macrophages (BMDM). Oroxyloside decreased several LPS-induced inflammatory cytokines, including IL-1β, IL-6 and TNF-α in RAW264.7 and BMDM. We also found that oroxyloside inhibited LPS-induced activation of NF-κB signaling pathway via activating PPARγ in RAW 264.7 and BMDM. Docking study showed that oroxyloside could bind with PPARγ. GW9662, the inhibitor of PPARγ, and PPARγ siRNA transfection blocked the effect of oroxyloside on PPARγ activation. Our study suggested that oroxyloside prevented DSS-induced colitis by inhibiting NF-κB pathway through PPARγ activation. Therefore, oroxyloside may be a promising and effective agent for inflammatory bowel disease (IBD).

Role of serotonin and nuclear factor-kappa B in the ameliorative effect of ginger on acetic acid-induced colitis

The current study was designed to investigate the role of serotonin (5-HT) and nuclear factor-kappa beta (NF-κB) in the ameliorative effect of ginger on acetic acid (AA)-induced colitis rat model. Colitis was induced by intra-colonic instillation of 3% AA, preceded or followed by daily administration of ginger (400mg/kg) by gavage for 5 days. Colons were assessed macroscopically and microscopically and the expression of NF-κB was evaluated by immunohistochemistry. Colonic tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), total peroxide (TP), and serum 5-HT levels were assessed. Administration of ginger ameliorated the effects of AA-induced colitis by plummeting colon weight-to-length ratio, macroscopic and microscopic scores. These effects were further supported by down-regulation of NF-κB and reduction of colonic TNF-α, IL-10, TP and serum 5-HT levels. Moreover, there were significant positive correlations between serum 5-HT and macroscopic, microscopic, immunoreactivity scores and colonic TNF-α level. In conclusion, ginger ameliorated AA-induced colitis not only through its anti-inflammatory and anti-oxidant properties, but also through the reduction of 5-HT which may contribute to the down-regulation of NF-κB-dependent TNF-α expression and the reduction of lipid peroxidation and tissue damage. In addition, the therapeutic effect of ginger was more pronounced than its preventive effect.

Intestinal anti-inflammatory activity of the seeds of Raphanus sativus L. in experimental ulcerative colitis models

ETHNOPHARMACOLOGICAL RELEVANCE

Water extract of Raphanus sativus L. (RSL) seeds was traditionally used to treat digestive inflammatory complaints in Korean culture. RSL seeds exerted antioxidant, anti-inflammatory, and anti-septic functions, suggesting their pharmacological potential for the treatment of inflammatory pathologies associated with oxidative stress such as inflammatory bowel disease.

AIM OF THIS STUDY

We evaluated the intestinal anti-inflammatory effects of RSL seed water extract (RWE) in experimental rat models of trinitrobenzenesulphonic acid (TNBS)- or dextran sodium sulfate (DSS)-induced colitis.

MATERIALS AND METHODS

RWE was characterized by determining the content of sinapic acid as a reference material and then assayed in the DSS and TNBS models of rat colitis. Male Sprague-Dawley rats were divided into 10 groups (n=7/group): non-colitic control, DSS or TNBS control, DSS colitis groups treated with RWE (100mg/kg) or mesalazine (25mg/kg), and TNBS colitis groups treated with various doses (10, 40, 70, and 100mg/kg) of RWE or mesalazine (25mg/kg). RWE or mesalazine treatment started the same day of colitis induction and rats were sacrificed 24h after the last treatment followed by histological and biochemical analyses.

RESULTS

Oral administration with RWE suppressed intestinal inflammatory damages in both DSS- and TNBS-induced colitic rats. The treatment with 100mg/kg RWE recovered intestinal damages caused by TNBS or DSS to levels similar to that of mesalazine, decreasing the activity of myeloperoxidase activity and the secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1β. RWE treatment inhibited malondialdehyde production and glutathione reduction in colon of colitis rats. The administration of RWE at dose of 100mg/kg also suppressed the TNBS- or DSS-stimulated expression of TNF-α, IL-1β, monocyte chemotactic protein-1, inducible nitric oxide, and intercellular adhesion molecule-1. Furthermore, RWE inhibited p38 kinase and DNA-nuclear factor-κB binding activities, both of which were stimulated in the colitic rats.

CONCLUSIONS

The current findings show that RWE ameliorates intestinal oxidative and inflammatory damages in DSS and TNBS models of rat colitis, suggesting its beneficial use for the treatment of intestinal inflammatory disorders.

Salvianolic Acid B Restored Impaired Barrier Function via Downregulation of MLCK by microRNA-1 in Rat Colitis Model

Salvianolic acid B (Sal B) is isolated from the traditional Chinese medical herb Salvia miltiorrhiza and is reported to have a wide range of therapeutic benefits. The aim of this study was to investigate the effects of Sal B on epithelial barrier dysfunction in rat colitis and to uncover related mechanisms. Rat colitis model was established by intracolonic administration of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). The intestinal barrier function was evaluated by measuring the serum recovery of fluorescein isothiocyanate-4 kD dextran in vivo and transepithelial electrical resistance in vitro respectively. The protein expression related to intestinal barrier function was studied using western blotting. The effects of Sal B on inflammatory responses, oxidative damage and colitis recurrence were also studied in this study. The intestinal barrier dysfunction in colitis was reversed by Sal B, accompanied with the decrease of tight junction proteins, and the effect could be blocked by microRNA-1(miR-1) inhibition. The inflammatory responses, oxidative damage and colitis recurrence were also decreased by Sal B. The colitis symptoms and recurrences were ameliorated by Sal B, and restoration of impaired barrier function via downregulation of MLCK by miR-1 maybe involved in this effect. This study provides some novel insights into both of the pathological mechanisms and treatment alternatives of inflammatory bowel disease.

Antioxidant therapy for treatment of inflammatory bowel disease: Does it work?

Oxidative stress (OS) is considered as one of the etiologic factors involved in several signals and symptoms of inflammatory bowel diseases (IBD) that include diarrhea, toxic megacolon and abdominal pain. This systematic review discusses approaches, challenges and perspectives into the use of nontraditional antioxidant therapy on IBD, including natural and synthetic compounds in both human and animal models. One hundred and thirty four papers were identified, of which only four were evaluated in humans. Some of the challenges identified in this review can shed light on this fact: lack of standardization of OS biomarkers, absence of safety data and clinical trials for the chemicals and biological molecules, as well as the fact that most of the compounds were not repeatedly tested in several situations, including acute and chronic colitis. This review hopes to stimulate researchers to become more involved in this fruitful area, to warrant investigation of novel, alternative and efficacious antioxidant-based therapies.

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Major biomarkers used for evaluation of antioxidant therapy were MPO, TBARS/MDA and glutathione levels.

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Challenges were identified for the yet poor use of antioxidant therapy in IBD.

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This review stimulates the investigation of alternative and efficacious antioxidant therapies.

Computational drug repositioning for peripheral arterial disease: prediction of anti-inflammatory and pro-angiogenic therapeutics

Peripheral arterial disease (PAD) results from atherosclerosis that leads to blocked arteries and reduced blood flow, most commonly in the arteries of the legs. PAD clinical trials to induce angiogenesis to improve blood flow conducted in the last decade have not succeeded. We have recently constructed PADPIN, protein-protein interaction network (PIN) of PAD, and here we combine it with the drug-target relations to identify potential drug targets for PAD. Specifically, the proteins in the PADPIN were classified as belonging to the angiome, immunome, and arteriome, characterizing the processes of angiogenesis, immune response/inflammation, and arteriogenesis, respectively. Using the network-based approach we predict the candidate drugs for repositioning that have potential applications to PAD. By compiling the drug information in two drug databases DrugBank and PharmGKB, we predict FDA-approved drugs whose targets are the proteins annotated as anti-angiogenic and pro-inflammatory, respectively. Examples of pro-angiogenic drugs are carvedilol and urokinase. Examples of anti-inflammatory drugs are ACE inhibitors and maraviroc. This is the first computational drug repositioning study for PAD.

Active components alignment of Gegenqinlian decoction protects ulcerative colitis by attenuating inflammatory and oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Gegenqinlian Decoction (GQD) has been used as a folk remedy for gastrointestinal diseases in China over thousands of years. It has significant treatment efficacy for patients with inflammatory bowel disease (IBD). We analyzed and showed that the active components alignment of Gegenqinlian Decoction (ACAG) possesses broad pharmacological effects including analgesic, antipyretic, anti-inflammatory, antibacterial, antiviral and antidiarrhea, as well as the effect of adjusting gastrointestinal function in our preliminary experiments. However, the exact molecular mechanisms on how ACAG exerts these pharmacological effects still remain elusive. In the present study, the plausible pharmacological effects of ACAG on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis were investigated.

MATERIALS AND METHODS

Male Sprague-Dawley (SD) rats with TNBS/ethanol-induced colitis were used. The colonic wet weight, macroscopic and histological colon injury, superoxide dismutase (SOD), malonyldialdehyde (MDA), and inducible nitric oxide synthase (iNOS) activity were observed. Pro-inflammation cytokines were determined by ELISA methods, semi-quantitative RT-PCR and Immuno-histochemistry.

RESULTS

We showed administration of ACAG was able to improve colitis. This was manifested by a decreased in the score of macroscopic and histological colonic injury, by lowered colonic wet weight, accompanied by significant increased of SOD activity, and decreased of MDA and iNOS activities. The treatment also significantly reduced tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) levels in colon and serum as well as the colonic mRNA levels for several inflammatory cytokines such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), macrophage inflammatory protein-2 (MIP-2), intercellular adhesion molecule-1 (ICAM-1) and toll-like receptor 2, 4 (TLR2, TLR4). In addition, we also showed that ACAG was able to inhibit the activation and translocation of transcription factors, nuclear factor kappaBp65 (NF-κBp65) in colon.

CONCLUSIONS

Our results suggest that ACAG exhibits protective effect in TNBS-induced ulcerative colitis. We postulate that this might be due to its modulation of oxidant/anti-oxidant balance, downregulation of productions, expressions of pro-inflammatory cytokines and inhibition of NF-κBp65 signal transduction pathways.

Red Ginseng and Semen Coicis can improve the structure of gut microbiota and relieve the symptoms of ulcerative colitis

ETHNOPHARMACOLOGICAL RELEVANCE

Many Chinese herbs are traditionally used as medicine to improve the functions of gastrointestinal tract. Some of these herbs are also promising agents for the improvement of the gut microbiota and the treatment of ulcerative colitis.

MATERIALS AND METHODS

By screening seven traditional Chinese herbs, we found that Red Ginseng and Semen Coicis were the most effective in promoting the growth of probiotics including Lactobacillus and Bifidobacterium in vitro. We then evaluated the effects of Red Ginseng and Semen Coicis on the growth of the bacterial pathogens (Escherichia coli, Staphylococcus aureus, and Salmonella spp.) in vitro. In in vivo experiment, we gavage administrated trinitro-benzene-sulfonic acid induced ulcerative colitis (UC) rats with Red Ginseng and Semen Coicis extracts. After two weeks treatment, we analyzed the structure of the gut microbiota and examined the UC symptoms by employing qPCR and animal pathology detection techniques.

RESULTS

Both Red Ginseng and Semen Coicis promoted the growth of probiotics - Bifidobacterium and Lactobacillus in vitro. Red Ginseng also inhibited the growth of some pathogen strains. In vivo, Red Ginseng and Semen Coicis improved the structure of gut microbiota and relieved the symptoms of ulcerative colitis in vivo. Compared with Semen Coicis, Red Ginseng was more effective in relieving the symptoms of ulcerative colitis.

CONCLUSIONS

Red Ginseng could promote the growth of probiotic bacteria in vitro. Red Ginseng and, to a lesser extent Semen Coicis, gave positive results in an experimental in vivo model for ulcerative colitis.

Azilsartan reduced TNF-α and IL-1β levels, increased IL-10 levels and upregulated VEGF, FGF, KGF, and TGF-α in an oral mucositis model

Oral mucositis (OM) is a common complication of treatments for head and neck cancer, particularly radiotherapy with or without chemotherapy. OM is characterised by oral erythema, ulceration, and pain. The aim of this study was to evaluate the effect of azilsartan (AZT), an angiotensin II receptor antagonist, on 5-fluorouracil (5-FU)-induced oral mucositis (OM) in Syrian hamsters. OM was induced by the intraperitoneal administration of 5-FU on experimental days 1 (60 mg/Kg) and 2 (40 mg/Kg). Animals were pretreated with oral AZT (1, 5, or 10 mg/kg) or vehicle 30 min before 5-FU injection and daily until day 10. Experimental treatment protocols were approved by the Animal Ethics Committee Use/CEUA (Number 28/2012) of the UFRN. Macroscopic analysis and cheek pouch samples were removed for histopathologic analysis. Myeloperoxidase (MPO), Malonyldialdehyde (MDA), interleukin-1 beta (IL-1β), interleukin-10 (IL-10), and tumour necrosis factor-alpha (TNF-α) were analysed by Enzyme Linked Immuno Sorbent Assay (ELISA). Vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), keratinocyte growth factor (KGF), and transforming growth factor (TGF)-α were measured by immunohistochemistry. Analysis of variance followed by Bonferroni's test was used to calculate the means of intergroup differences (p ≤ 0.05). Treatment with 1 mg/kg AZT reduced levels MPO (p<0.01), MDA (p<0.5) and histological inflammatory cell infiltration, and increased the presence of granulation tissue. AZT treatment at 1 mg/kg reduced the TNF-α (p<0.05) and IL-1β (p<0.05) levels, increased the cheek pouch levels of IL-10 (p<0.01), and upregulated VEGF, FGF, KGF, and TGF-α. Administration of AZT at higher doses (5 and 10 mg/kg) did not significantly reverse the OM. AZT at a dose of 1 mg/kg prevented the mucosal damage and inflammation associated with 5-FU-induced OM, increasing granulation and tissue repair.

Dietary agents and phytochemicals in the prevention and treatment of experimental ulcerative colitis

Inflammatory bowel diseases (IBDs), consisting mainly of ulcerative colitis (UC) and Crohn's disease (CD), are important immune-mediated diseases of the gastrointestinal tract. The etiology of the disease includes environmental and genetic factors. Its management presents a constant challenge for gastroenterologists and conventional surgeon. 5-Amninosalicylates, antibiotics, steroids, and immune modulators have been used to reduce the symptoms and for maintenance of remission. Unfortunately, long-term usage of these agents has been found to lead to severe toxicities, which are deterrent to the users. Pre-clinical studies carried out in the recent past have shown that certain dietary agents, spices, oils, and dietary phytochemicals that are consumed regularly possess beneficial effects in preventing/ameliorating UC. For the first time, this review addresses the use of these dietary agents and spices in the treatment and prevention of IBD and also emphasizes on the mechanisms responsible for their effects.

Telmisartan attenuates colon inflammation, oxidative perturbations and apoptosis in a rat model of experimental inflammatory bowel disease

Accumulating evidence has indicated the implication of angiotensin II in the pathogenesis of inflammatory bowel diseases (IBD) via its proinflammatory features. Telmisartan (TLM) is an angiotensin II receptor antagonist with marked anti-inflammatory and antioxidant actions that mediated its cardio-, reno- and hepatoprotective actions. However, its impact on IBD has not been previously explored. Thus, we aimed to investigate the potential alleviating effects of TLM in tri-nitrobenezene sulphonic acid (TNBS)-induced colitis in rats. Pretreatment with TLM (10 mg/kg p.o.) attenuated the severity of colitis as evidenced by decrease of disease activity index (DAI), colon weight/length ratio, macroscopic damage, histopathological findings and leukocyte migration. TLM suppressed the inflammatory response via attenuation of tumor necrosis factor-α (TNF-α), prostaglandin E₂ (PGE₂) and myeloperoxidase (MPO) activity as a marker of neutrophil infiltration besides restoration of interleukin-10 (IL-10). TLM also suppressed mRNA and protein expression of nuclear factor kappa B (NF-κB) p65 and mRNA of cyclo-oxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) proinflammatory genes with concomitant upregulation of PPAR-γ. The alleviation of TLM to colon injury was also associated with inhibition of oxidative stress as evidenced by suppression of lipid peroxides and nitric oxide (NO) besides boosting glutathione (GSH), total anti-oxidant capacity (TAC) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). With respect to apoptosis, TLM downregulated the increased mRNA, protein expression and activity of caspase-3. It also suppressed the elevation of cytochrome c and Bax mRNA besides the upregulation of Bcl-2. Together, these findings highlight evidences for the beneficial effects of TLM in IBD which are mediated through modulation of colonic inflammation, oxidative stress and apoptosis.

Inhibition of tumor necrosis factor-alpha and cyclooxigenase-2 by Isatin: a molecular mechanism of protection against TNBS-induced colitis in rats

Isatin, an indole alkaloid has been shown to have anti-microbial, anti-tumor and anti-inflammatory effects. Due to its findings, we evaluated whether this alkaloid would have any effect on TNBS-induced colitis. Animals (male Unib:WH rats, aged 8 weeks old) were induced colitis through a rectal administration of 2,4,6-trinitrobenzene sulphonic acid using a catheter inserted 8 cm into the rectum of the animals. The rats were divided into two major groups: non-colitic and colitic. The colitic group was sub-divided into 6 groups (10 animals per group): colitic non-treated, Isatin 3; 6; 12.5; 18.75 and 25 mg/kg. Our main results showed that the oral treatment with Isatin 6 and 25 mg/kg were capable of avoiding the increase in TNF-α, COX-2 and PGE₂ levels when compared to the colitic non-treated group. Interestingly, the same doses (6 and 25 mg/kg) were also capable of preventing the decrease in IL-10 levels comparing with the colitic non-treated group. The levels of MPO, (an indirect indicator of neutrophil presence), were also maintained lower than those of the colitic non-treated group. Isatin also prevented the decrease of SOD activity and increase of GSH-Px and GSH-Rd activity as well as the depletion of GSH levels. In conclusion, both pre-treatments (6 and 25 mg/kg) were capable of protecting the gut mucosa against the injury caused by TNBS, through the combination of antioxidant and anti-inflammatory properties, which, together, showed a protective activity of the indole alkaloid Isatin.

Phytol, a diterpene alcohol, inhibits the inflammatory response by reducing cytokine production and oxidative stress

Studies have shown that diterpenes have anti-inflammatory and redox-protective pharmacological activities. The present study aimed to investigate the anti-inflammatory properties of phytol, a diterpene alcohol, in a mouse model of acute inflammation, and phytol effect on leukocyte recruitment, cytokines levels, and oxidative stress. The anti-inflammatory activities of phytol were assessed by measuring paw edema induced by different inflammatory agents (e.g., λ-carrageenan, compound 48/80, histamine, serotonin, bradykinin, and prostaglandin E2 [PGE2 ]), myeloperoxidase (MPO) activity, peritonitis model and cytokine levels. Further, oxidative stress was evaluated by determining glutathione (GSH) levels and malondialdehyde (MDA) concentration. The results showed that phytol (7.5, 25, 50, and 75 mg/kg) significantly reduced carrageenan-induced paw edema, in a dose-dependent manner. In addition, phytol (75 mg/kg) inhibited compound 48/80-, histamine-, serotonin-, bradykinin- and PGE2 -induced paw edema. It also inhibited the recruitment of total leukocytes and neutrophils; decreased MPO activity, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels, and MDA concentration; and increased GSH levels during carrageenan-induced acute inflammation. These results suggest that phytol attenuates the inflammatory response by inhibiting neutrophil migration that is partly caused by reduction in IL-1β and TNF-α levels and oxidative stress.