10 research outputs found

    Aluminum Ingestion Promotes Colorectal Hypersensitivity in Rodents

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    Background & Aims: Irritable bowel syndrome (IBS) is a multifactorial disease arising from a complex interplay between genetic predisposition and environmental influences. To date, environmental triggers are not well known. Aluminum is commonly present in food, notably by its use as food additive. We investigated the effects of aluminum ingestion in rodent models of visceral hypersensitivity, and the mechanisms involved. Methods: Visceral hypersensitivity was recorded by colorectal distension in rats administered with oral low doses of aluminum. Inflammation was analyzed in the colon of aluminum-treated rats by quantitative PCR for cytokine expression and by immunohistochemistry for immune cells quantification. Involvement of mast cells in the aluminum-induced hypersensitivity was determined by cromoglycate administration of rats and in mast cell-deficient mice (Kit). Proteinase-activated receptor-2 (PAR2) activation in response to aluminum was evaluated and its implication in aluminum-induced hypersensitivity was assessed in PAR2 knockout mice. Results: Orally administered low-dose aluminum induced visceral hypersensitivity in rats and mice. Visceral pain induced by aluminum persisted over time even after cessation of treatment, reappeared and was amplified when treatment resumed. As observed in humans, female animals were more sensitive than males. Major mediators of nociception were up-regulated in the colon by aluminum. Activation of mast cells and PAR2 were required for aluminum-induced hypersensitivity. Conclusions: These findings indicate that oral exposure to aluminum at human dietary level reproduces clinical and molecular features of IBS, highlighting a new pathway of prevention and treatment of visceral pain in some susceptible patients

    The RAGE signaling pathway is involved in intestinal inflammation and represents a promising therapeutic target for Inflammatory Bowel Diseases.

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    International audienceInflammatory Bowel Diseases (IBD) are chronic inflammatory conditions of the intestinal tract. IBD are believed to result from an inappropriate immune response against the intestinal flora in genetically predisposed patients. The precise etiology of these diseases is not fully understood, therefore treatments rely on the dampening of symptoms, essentially inflammation, rather than on the cure of the disease. Despite the availability of biologics, such as anti-TNF antibodies, some patients remain in therapeutic failure and new treatments are thus needed. The multiligand receptor for advanced glycation end-products (RAGE) is a pattern recognition receptor implicated in inflammatory reactions and immune system activation. Here, we investigated the role of RAGE in intestinal inflammation and its potential as a therapeutic target in IBD. We showed that RAGE was upregulated in inflamed tissues from IBD patients compared to controls. Rage(-/-) mice were less susceptible to intestinal and colonic inflammation development than WT mice. WT mice treated with the RAGE-specific inhibitor FPS-ZM1 experienced less severe enteritis and colitis. We demonstrated that RAGE could induce intestinal inflammation by promoting oxidative stress and endothelial activation which were diminished by FPS-ZM1 treatment. Our results revealed the RAGE signaling pathway as a promising therapeutic target for IBD patients

    3-Carboxamido-5-aryl-isoxazoles as new CB2 agonists for the treatment of colitis.

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    Recent investigations showed that anandamide, the main endogenous ligand of CB1 and CB2 cannabinoid receptors, possesses analgesic, antidepressant and anti-inflammatory effects. In the perspective to treat inflammatory bowel disease (IBD), our approach was to develop new selective CB2 receptor agonists without psychotropic side effects associated to CB1 receptors. In this purpose, a new series of 3-carboxamido-5-aryl-isoxazoles, never described previously as CB2 receptor agonists, was designed, synthesized and evaluated for their biological activity. The pharmacological results have identified great selective CB2 agonists with in vivo anti-inflammatory activity in a DSS-induced acute colitis mouse model

    Aluminum enhances inflammation and decreases mucosal healing in experimental colitis in mice

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    The increasing incidence of inflammatory bowel diseases (IBDs) in developing countries has highlighted the critical role of environmental pollutants as causative factors in their pathophysiology. Despite its ubiquity and immune toxicity, the impact of aluminum in the gut is not known. This study aimed to evaluate the effects of environmentally relevant intoxication with aluminum in murine models of colitis and to explore the underlying mechanisms. Oral administration of aluminum worsened intestinal inflammation in mice with 2,4,6-trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis and chronic colitis in interleukin 10-negative (IL10(-/-)) mice. Aluminum increased the intensity and duration of macroscopic and histologic inflammation, colonic myeloperoxidase activity, inflammatory cytokines expression, and decreased the epithelial cell renewal compared with control animals. Under basal conditions, aluminum impaired intestinal barrier function. In vitro, aluminum induced granuloma formation and synergized with lipopolysaccharide to stimulate inflammatory cytokines expression by epithelial cells. Deleterious effects of aluminum on intestinal inflammation and mucosal repair strongly suggest that aluminum might be an environmental IBD risk factor.Mucosal Immunology advance online publication, 16 October 2013; doi:10.1038/mi.2013.78

    4‑Oxo-1,4-dihydropyridines as Selective CB<sub>2</sub> Cannabinoid Receptor Ligands Part 2: Discovery of New Agonists Endowed with Protective Effect Against Experimental Colitis

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    Further on to our earlier work on the 4-oxo-1,4-dihydropyridine, we describe herein our strategy to get access to potent selective CB<sub>2</sub> receptor agonists. Thus, we designed and synthesized 29 compounds, evaluated on both <i>h</i>CB<sub>1</sub> and <i>h</i>CB<sub>2</sub> cannabinoid receptors, and assessed 11 of them in the TNBS-induced colitis model in mice. Compound <b>48</b> was found to be the most efficient of our series, exhibiting an exquisite protection against experimental colitis, superior to the one observed after treatment with Pentasa

    3-Carboxamido-5-aryl-isoxazoles as new CB2 agonists for the treatment of colitis

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    Recent investigations showed that anandamide, the main endogenous ligand of CB1 and CB2 cannabinoid receptors, possesses analgesic, antidepressant and anti-inflammatory effects. In the perspective to treat inflammatory bowel disease (IBD), our approach was to develop new selective CB2 receptor agonists without psychotropic side effects associated to CB1 receptors. In this purpose, a new series of 3-carboxamido-5-aryl-isoxazoles, never described previously as CB2 receptor agonists, was designed, synthesized and evaluated for their biological activity. The pharmacological results have identified great selective CB2 agonists with in vivo anti-inflammatory activity in a DSS-induced acute colitis mouse model
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