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Background: Intestinal fibrosis is a common complication in inflammatory bowel disease (IBD) patients without specific treatment. Aryl hydrocarbon receptor (AhR) activation is associated with better outcomes in intestinal inflammation. Development of novel therapies targeting fibrogenic pathways is required and we aimed to screen dietary AhR ligands for their anti-fibrotic properties in TGF-β1-stimulated human colonic fibroblast cells. Methods: The study was conducted using TGF-β1-stimulated CCD-18Co, a human colonic fibroblast cell line in response to increased concentrations of dietary ligands of AhR such as FICZ, ITE, L-kynurenine and curcumin. Fibrosis markers such as α-SMA, COL1A1, COL3A1 and CTGF were assessed. AhR and ANRT RNA were evaluated. Results: TGF-β1 at 10 ng/mL significantly induced mRNA levels for ECM-associated proteins such as CTGF, COL1A1 and COL3A1 in CCD-18Co cells. FICZ from 10 to 1000 nM, L-kynurenine from 0.1 to 10 μM, ITE from 1 to 100 μM or curcumin from 5 to 20 μM had no significant effect on fibrosis markers in TGF-β1-induced CCD-18Co. Conclusions: Our data highlight that none of the tested dietary AhR ligands had an effect on fibrosis markers in TGF-β1-stimulated human colonic fibroblast cells in our experimental conditions. Further studies are now required to identify novel potential targets in intestinal fibrosis.

Pre-pubertal murine models of acute colitis are lacking. Magnetic resonance colonography (MRC) is a promising minimally invasive tool to assess colitis. We aimed to: 1/ Adapt a model of acute experimental colitis to pre-pubertal rats and determine whether MRC characteristics correlate with histological inflammation. 2/ Test this model by administering a diet supplemented in transforming growth factor β2 to reverse inflammation. Twenty-four rats were randomized at weaning to one of 3 groups: Trinitrobenzene Sulfonic Acid (TNBS) group (n = 8) fed a standard diet, that received an intra-rectal 60 mg/kg dose of TNBS-ethanol; Control group (n = 8) fed standard diet, that received a dose of intra-rectal PBS; TNBS+MODULEN group (n = 8) that received a dose of TNBS and were exclusively fed MODULEN-IBD® after induction of colitis. One week after induction of colitis, rats were assessed by MRC, colon histopathology and inflammation markers (Interleukin 1β, Tumor necrosis factor α, Nitric Oxide Synthase 2 and Cyclooxygenase 2). TNBS induced typical features of acute colitis on histopathology and MRC (increased colon wall thickness, increased colon intensity on T2-weighted images, target sign, ulcers). Treatment with MODULEN-IBD® did not reduce signs of colitis on MRC. Inflammatory marker expression did not differ among study groups.

International audience; The natural history of inflammatory bowel diseases, especially Crohn’s disease, is frequently complicated by intestinal fibrosis. Because of the lack of effective treatments for intestinal fibrosis, there is an urgent need to develop new therapies. Factors promoting intestinal fibrosis are currently unclear, but diet is a potential culprit. Diet may influence predisposition to develop intestinal fibrosis or alter its natural history by modification of both the host immune response and intestinal microbial composition. Few studies have documented the effects of dietary factors in modulating IBD-induced intestinal fibrosis. As the mechanisms behind fibrogenesis in the gut are believed to be broadly similar to those from extra-intestinal organs, it may be relevant to investigate which dietary components can inhibit or promote fibrosis factors such as myofibroblasts progenitor activation in other fibrotic diseases.

Intestinal fibrosis is a frequent complication in inflammatory bowel diseases (IBD). It is a challenge to identify environmental factors such as diet that may be driving this risk. Intestinal fibrosis result from accumulation of extracellular matrix (ECM) proteins secreted by myofibroblasts. Factors promoting intestinal fibrosis are unknown, but diet appears to be a critical component in its development. Consumption of salt above nutritional recommendations can exacerbate chronic inflammation. So far, high salt diet (HSD) have not been thoroughly investigated in the context of intestinal fibrosis associated to IBD. In the present study, we analyze the role of dietary salt in TNBS chronic colitis induced in rat, an intestinal fibrosis model, or in human colon fibroblast cells. Here, we have shown that high-salt diet exacerbates undernutrition and promoted ECM-associated proteins in fibroblasts. Taken together, our results suggested that dietary salt can activate intestinal fibroblasts, thereby contributing to exacerbation of intestinal fibrosis. Dietary salt may be considered as a putative environmental factor that drives intestinal fibrosis risk.

Undernutrition is a global health issue leading to 1 out 5 all deaths in children under 5 years. Undernutrition is often associated with environmental enteric dysfunction (EED), a syndrome associated with increased intestinal permeability and gut inflammation. We aimed to develop a novel murine model of undernutrition with these EED features. Post-weaning mice were fed with low-protein diet (LP) alone or combined with a gastrointestinal insult trigger (indomethacin or liposaccharides). Growth, intestinal permeability and inflammation were assessed. LP diet induced stunting and wasting in post-weaning mice but did not impact gut barrier. We therefore combined LP diet with a single administration of indomethacin or liposaccharides (LPS). Indomethacin increased fecal calprotectin production while LPS did not. To amplify indomethacin effects, we investigated its repeated administration in addition to LP diet and mice exhibited stunting and wasting with intestinal hyperpermeability and gut inflammation. The combination of 3-weeks LP diet with repeated oral indomethacin administration induced wasting, stunting and gut barrier dysfunction as observed in undernourished children with EED. As noninvasive methods for investigating gut function in undernourished children are scarce, the present pre-clinical model provides an affordable tool to attempt to elucidate pathophysiological processes involved in EED and to identify novel therapeutic strategies.

Undernutrition is a major public health problem leading to 1 in 5 of all deaths in children under 5 years. Undernutrition leads to growth stunting and/or wasting and is often associated with environmental enteric dysfunction (EED). EED mechanisms leading to growth failure include intestinal hyperpermeability, villus blunting, malabsorption and gut inflammation. As non-invasive methods for investigating gut function in undernourished children are limited, pre-clinical models are relevant to elucidating the pathophysiological processes involved in undernutrition and EED, and to identifying novel therapeutic strategies. In many published models, undernutrition was induced using protein or micronutrient deficient diets, but these experimental models were not associated with EED. Enteropathy models mainly used gastrointestinal injury triggers. These models are presented in this review. We found only a few studies investigating the combination of undernutrition and enteropathy. This highlights the need for further developments to establish an experimental model reproducing the impact of undernutrition and enteropathy on growth, intestinal hyperpermeability and inflammation, that could be suitable for preclinical evaluation of innovative therapeutic intervention.

Inflammatory bowel diseases (IBDs) develop in genetically predisposed individuals in response to environmental factors. IBDs are concomitant conditions of industrialized societies, and diet is a potential culprit. Consumption of ultra-processed food has increased over the last decade in industrialized countries, and epidemiological studies have found associations between ultra-processed food consumption and chronic diseases. Further studies are now required to identify the potential culprit in ultra-processed food, such as a poor nutritional composition or the presence of food additives. In our review, we will focus on food additives, i.e., substances from packaging in contact with food, and compounds formed during production, processing, and storage. A literature search using PubMed from inception to January 2019 was performed to identify relevant studies on diet and/or food additive and their role in IBDs. Manuscripts published in English from basic science, epidemiological studies, or clinical trials were selected and reviewed. We found numerous experimental studies highlighting the key role of food additives in IBD exacerbation but epidemiological studies on food additives on IBD risk are still limited. As diet is a modifiable environmental risk factor, this may offer a scientific rationale for providing dietary advice for IBD patients.

International audience; Peroxisome proliferator-activated receptor γ (PPARγ) belongs to the family of nuclear nuclear receptors and is mainly expressed in adipose tissue, hematopoietic cells and the large intestine. Contrary to other nuclear receptors that mainly bind a single specific ligand, there are numerous natural PPARγ ligands, in particular fatty acids or their derivatives called eicosanoids. PPARγ have pleiotropic functions: (i) glucose and lipid metabolism regulation, (ii) anti-inflammatory properties, (iii) oxidative stress inhibition, (iv) improvement of endothelial function. Its role has been mainly studied by the use synthetic agonists. In this review, we will focus on the effects of PPARγ mediated through fatty acids and how these have beneficial health properties.

Inflammation is a protective process for life that aims to restore body homeostasis by targeting the injury and by inducing repair mechanisms. This process can also become excessive and lead to chronic inflammation and organ fibrosis. Polyunsaturated fatty acids play a key role in inflammatory processes and their resolution. Indeed, numerous lipid mediators derived from n-3 or n-6 PUFA such as eicosanoids, endocannabinoids, or proresolving lipids are able to target transcription factors to modulate gene expression. One other important action mechanism is by modification of cell membrane composition. The purpose of the present review is to describe the potential mechanisms by which PUFA influence inflammatory processes. To illustrate this purpose, we focused on the interactions between PUFA and intestinal inflammation as an integrative example.

Ubiquitin proteasome system contributes to the regulation of intestinal inflammatory response as its inhibition is associated with tissue damage improvement. We aimed to evaluate whether glutamine is able to limit inflammation by targeting ubiquitin proteasome system in experimental colitis. Colitis was induced in male rats by intrarectal instillation of 2-4-6-trinitrobenzen sulfonic acid (TNBS) at day 1. From day 2 to day 6, rats daily received either an intrarectal instillation of PBS (TNBS/PBS group) or glutamine (TNBS/Gln). Rats were euthanized at day 7 and colonic samples were taken to evaluate ubiqutinated proteins by proteomic approach combining 2D electrophoresis and immunoblots directed against ubiquitin. Results were then confirmed by evaluating total expression of proteins and mRNA levels. Survival rate, TNFα, and IL-1β mRNA were improved in TNBS/Gln compared with TNBS/PBS (p < 0.05). Proteasome activities were affected by TNBS but not by glutamine. We identified eight proteins that were less ubiquitinated in TNBS/PBS compared with controls with no effect of glutamine. Four proteins were more ubiquitinated in TNBS/PBS group and restored in TNBS/Gln group. Finally, 12 ubiquitinated proteins were only affected by glutamine. Among proteins affected by glutamine, eight proteins (GFPT1, Gapdh, Pkm2, LDH, Bcat2, ATP5a1, Vdac1, and Vdac2) were involved in metabolic pathways. In conclusion, glutamine may regulate ubiquitination process during intestinal inflammation.

Background. Inflammatory bowel diseases (IBD) occurred in genetically predisposed people exposed to environmental triggers. Diet has long been suspected to contribute to the development of IBD. Supplementation with n-3 polyunsaturated fatty acids (PUFA) protects against intestinal inflammation in rodent models while clinical trials showed no benefits. We hypothesized that intervention timing is crucial and dietary fatty acid pattern may influence intestinal environment to modify inflammation genesis. The aim of this study was to evaluate the dietary effect of PUFA composition on intestinal inflammation.Methods. Animals received diet varying in their PUFA composition for four weeks before TNBS-induced colitis. Colon inflammatory markers and gut barrier function parameters were assessed. Inflammatory pathway PCR arrays were determined.Results. n-3 diet significantly decreased colon iNOS, COX-2 expression, IL-6 production, and LTB4 production but tended to decrease colon TNFαproduction (P=0.0617) compared to control diet. Tight junction protein (claudin-1, occludin) expressions and MUC2 and TFF3 mRNA levels were not different among groups. n-9 diet also decreased colon IL-6 production (P<0.05).Conclusions. Dietary n-3 PUFA influence colitis development by attenuating inflammatory markers. Further research is required to better define dietary advice with a scientific rationale.

Introduction et but de l’etude La malnutrition aigue severe (MAS) est un probleme majeur de sante publique, avec plus de 17 millions d’enfants âges de moins de 5 ans touches selon l’Unicef. La MAS se caracterise par une emaciation severe, souvent associee a une enteropathie environnementale (hyperpermeabilite, inflammation intestinale). Le but de cette etude est de developper un modele murin de MAS associe a une enteropathie en couplant une alimentation hypoproteinee a une injection soit de lipopolysaccharides, soit d’indometacine. Materiel et methodes Quarante souris mâles C57BL/6 âgees de 3 semaines ont recu soit un regime standard (Groupe controle ; 20 % de proteines ; n = 10), soit un regime hypoproteine (Groupe low protein (LP) ; 5 % de proteines ; n = 30) pendant 14 jours. A j11, les souris du groupe controle ont recu une injection intra-peritoneale d’eau tandis que les souris du groupe LP ont ete separees en 3 groupes recevant respectivement une injection intraperitoneale (i) d’eau (n = 10) pour le groupe LP seul, (ii) de LPS (1 mg.kg−1, n = 10) pour le groupe LP + LPS, (iii) d’indometacine (10 mg.kg−1, n = 10) pour le groupe LP + INDO. La croissance ponderale des animaux a ete suivie tous les 2 jours et la croissance lineaire a ete etudiee par la mesure de la longueur de la queue le jour du sacrifice (j14). La fonction de barriere intestinale a ete evaluee par la mesure de la permeabilite intestinale apres gavage des animaux par du FITC-Dextran. Le taux des ARNm codant pour les proteines de jonctions serrees (Claudine-2, occludine) a ete mesure au niveau jejunal. Nous avons mesure des marqueurs inflammatoires comme les taux de calprotectine fecale et d’ARNm codant pour les cytokines (TNF-α et MCP-1). Resultats et analyse statistique Le regime hypoproteine (i) induit un retard de croissance ponderale par rapport au groupe controle (14,2 ± 0,6 vs 21,8 ± 0,3 g ; p Conclusion La combinaison d’un regime hypoproteine a une injection d’indometacine induit chez les souris un retard de croissance, une hyperpermeabilite intestinale et une inflammation intestinale. Le modele avec injection d’indometacine semble donc plus proche de la physiopathologie humaine de la malnutrition associee a une enteropathie environnementale.

Recent epidemiological studies highlight the key role of the type of consumed unsaturated fatty acid and the development of ulcerative colitis (UC). We aimed to review the potential mechanisms behind the antiinflammatory effects of unsaturated fatty acids on intestinal inflammation, to discuss their potential limitations, and to propose a new reappraisal of polyunsaturated fatty acids (PUFAs) in the pathophysiology of inflammatory bowel disease (IBD). A literature search using PubMed was carried out to identify relevant studies (basic science, epidemiological studies, or clinical trials) with unsaturated fatty acids and IBD. Only articles published in English were included. IBD patients exhibit an altered lipid metabolism. While in vitro and in vivo studies have demonstrated the antiinflammatory properties of n-3 polyunsaturated fatty acids in experimental models IBD, results of clinical trials have been disappointing. In addition, the impact of fatty acid on innate immunity as an alternative therapeutic approach is explored. This may offer insight into therapeutic avenues for designing n-3 PUFA diet therapy for IBD.

AIM To assess the feasibility of SPECT-computed tomography (CT) in rats with trinitrobenzene sulfonic acid (TNBS)-induced acute colitis and confront it with model inflammatory characteristics. METHODS Colitis was induced in Sprague-Dawley rats by intrarectal injection of TNBS (n = 10) while controls received vehicle (n = 10). SPECT-CT with intravenous injection of 10 MBq of 67Ga-Citrate was performed at day 2. SPECT-CT criteria were colon wall thickness and maximal wall signal intensity. Laboratory parameters were assessed: colon weight:length ratio, colon cyclooxygenase-2 expression by western blot and histological inflammatory score. RESULTS Colon weight/length ratio, colon COX-2 expression and histological inflammatory score were significantly higher in the TNBS group than in the control group (P = 0.0296, P < 0.0001, P = 0.0007 respectively). Pixel max tend to be higher in the TNBS group than in the control group but did not reach statistical significance (P = 0.0662). Maximal thickness is significantly increased in the TNBS group compared to the control group (P = 0.0016) while colon diameter is not (P = 0.1904). Maximal thickness and colon diameter were correlated to colon COX-2 expression (P = 0.0093, P = 0.009 respectively) while pixel max was not (P = 0.22). Maximal thickness was significantly increased when inflammation was histologically observed (P = 0.0043) while pixel max and colon diameter did not (P = 0.2452, P = 0.3541, respectively). CONCLUSION SPECT-CT is feasible and easily distinguished control from colitic rats.

Background and Aims: Both science and patients associate diet with inflammatory bowel disease [IBD]. There is no doubt that links between IBD and diet are numerous, based on both epidemiological studies and experimental studies. However, scientific evidence to support dietary advice is currently lacking, and dietary counselling for IBD patients is often limited in clinical practice to the improvement of nutrient intake. This review aimed to focus on both patient’s beliefs about and molecular mechanisms for crosstalk between nutrients and inflammation. Methods: A literature search using PubMed was performed to identify relevant studies on diet and/or nutrients and their role in IBD. Pubmed [from inception to January 20, 2016] was searched using the terms: ‘Crohn’, ‘colitis’,’ intestinal epithelial cells’, and a list of terms relating to diet or numerous specific nutrients. Terms associated with nutrients were individually tested in the context of IBD. Reference lists from studies selected were manually searched to identify further relevant reports. Manuscripts about diet in the context of IBD from basic science, epidemiological studies, or clinical trials were selected and reviewed. Only articles published in English were included. Results: Epidemiological studies highlight the key role of diet in IBD development, and many IBD patients report diet as a triggering factor in relapse of disease. In addition, we present research on the impact of nutrients on innate immunity. Conclusion: Diet may offer an alternative approach to restoring deficient innate immunity in IBD, and this may be the scientific rationale for providing dietary counselling for IBD patients.

Objective The ω-3 polyunsaturated fatty acid therapy in inflammatory bowel disease is focused on the effects on fish oil–derived polyunsaturated fatty acids. We speculated that a vegetal oil rich in α-linolenic acid (ALA) might also inhibit colitis. Therefore, we evaluated whether dietary ALA would decrease the expression of adhesion molecules by inducing the protective enzyme heme oxygenase-1 (HO-1) in a rat colitis model. Methods Colitis was induced at day 0 by an intrarectal injection of 2-4-6-trinitrobenzen sulfonic acid (TNBS), whereas control rats received the vehicle. Rats were fed an ALA-rich formula 450 mg · kg −1 · d −1 , whereas the other colitic group (TNBS) and the control group were fed an isocaloric corn oil formula for 14 d (from day −7 to day 7). The colonic expressions of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), vascular endothelial growth factor A receptor-2 (VEGFR2), and HO-1 were studied by immunohistochemistry. Results The ALA-rich diet significantly decreased the expression of ICAM-1, VCAM-1, and VEGFR-2 compared the TNBS group, but it did not affect the expression of HO-1. Conclusion A vegetal ALA-rich formula decreases the expression of ICAM-1, VCAM-1, and VEGFR-2 and independently of HO-1 in rats with TNBS-induced colitis. Further studies are required to evaluate its therapeutic potential in inflammatory bowel disease as an alternative to fish oil.

Summary Background & aims Increased intestinal permeability of Irritable bowel syndrome (IBS) patients has been recently associated with a decreased level of glutamine synthetase. Neonatal maternal deprivation (NMD) is considered as an IBS-like model. The aim of our study was to investigate whether early nutritional intervention with glutamine may attenuate the deleterious impact of early life stress on gut barrier function in NMD. Methods 124 rat pups were separated from their dam 3 h daily during postnatal days 2–14, or left undisturbed (NS). Separated rats received by gavage either with alanyl-glutamine (GLN), an isonitrogenous amino acid mix (AA, control) or an equal amount of drinking water (H 2 O). Production of cytokines was measured by multiplex, expression of COX-2, PPARγ, tight junction proteins and TLR4 by western blot. Intestinal permeability was studied by Lactulose/Mannitol test. Results Treatment of pups with GLN or AA abolished the decrease in body weight observed in NMD. Treatment with GLN decreased in the colon (i) TLR4 expression at D20, (ii) IL-2 and -10 productions at D60 (iii) protein expression of occludin at D20 compared to AA. GLN also decreased colon expression of COX2 and PPARγ at D60 compared to NS. Colon production of IFNγ is significantly reduced by GLN compared to H 2 O. No significant change in intestinal permeability was observed. Conclusions These results showed that an early nutritional intervention with alanyl-glutamine specifically abolished the up-regulation of TLR4 expression in NMD. Glutamine may be evaluated as a potential treatment for IBS patients.

We have previously shown that α-linolenic acid (ALA), a (n-3) PUFA exerts in vitro antiinflammatory effects in the intestine. In this study, we aimed to evaluate its effect on inflammatory and oxidative stress in a colitis model. Colitis was induced in 2 groups at d 0 by intrarectal injection of 2-4-6-trinitrobenzen sulfonic acid (TNBS), whereas the control group received the vehicle. Rats we fed 450 mg . kg(-1) . d(-1) of ALA (TNBS+ALA) while the other colitic group (TNBS) and the control group were fed an isocaloric corn oil formula for 14 d (from d -7 to d 7). RBC fatty acid composition was assessed. Oxidative stress was studied by measuring urinary 8-isoprostanes (8-IP) and colon glutathione (GSH) concentration and inducible nitric oxide synthase (iNOS) expression. Colitis was assessed histologically, by production of proinflammatory mediators, including cytokines, leukotrienes B(4) (LTB(4)), and cyclooxygenase-2 (COX-2) and by nuclear factor-κB (NF-κB) activation. The ALA-rich diet significantly increased the RBC levels of ALA, eicosapentaenoic acid, and docosapentaenoic acid (n-3) compared with the TNBS group (P < 0.01 for all). The beneficial effect of ALA supplementation on oxidative stress was reflected by lower urinary 8-IP levels (P < 0.05), a normalized colon GSH concentration (P < 0.01), and reduced colon iNOS expression (P < 0.05) compared with the TNBS group. ALA also protected against colon inflammation as assessed by lower tumor necrosis factor-α secretion and mRNA level (P < 0.05), reduced NF-κB activation (P = 0.01), and lower colon lipid mediator concentrations such as LTB(4) and COX-2 (P < 0.05) compared with the TNBS group. These findings show that an ALA-rich formula is beneficial to TNBS-induced colitic rats via inhibition of oxidative and inflammatory stress.

The pathophysiology of inflammatory bowel diseases (IBDs) is multifactorial and involves interactions of gut luminal content with mucosal barrier and especially immune cells. Malnutrition is a frequent issue during IBD flares, especially in Crohn's disease (CD) patients, and nutritional support is frequently used to treat malnutrition but also in an attempt to modulate intestinal inflammation. The use of oral or enteral nutrition intervention in IBDs may be effective, alone or in combination with drugs, to achieve and maintain remission. However, standard diets are less effective than new-generation biotherapies and could be improved by supplementation with specific immunomodulatory amino acids. Experimental studies evaluating glutamine, the preferential substrate for enterocytes, are promising. Some clinical studies with oral glutamine in CD are until now disappointing, but new formulations and targeting could enhance glutamine efficacy at the site of mucosal lesions. The role of arginine, involved in nitric oxide and polyamines synthesis, still remains debated. However, the effects of these amino acids in IBD have been poorly documented in humans. Other candidates like glycine, cysteine, histidine, or taurine should also be evaluated in the future.

Glutamine (Gln) and arginine (Arg) are conditionally essential amino acids with immunomodulatory properties. The aim of the study was to assess the effects of Gln and Arg alone or in combination on cytokine release by cultured colonic biopsies from patients with active Crohn's disease (CD). Ten consecutive patients [mean (range) age 26 (18-39) y] with active colonic CD (mean CD activity index: 383.7 +/- 129.8) were prospectively included in the study. Eight colonic biopsies were obtained via a colonoscopy and incubated during 18 h with low (physiological) or high (pharmacological) doses of Arg (0.1 or 2 mmol/L designated as Arg(low) or Arg(high), respectively) and Gln (0.6 or 10 mmol/L designated as Gln(low) or Gln(high), respectively). The concentrations of cytokines [interleukin (IL)-4, IL-10, IL-8, IL-6, tumor necrosis factor-alpha (TNFalpha), IL-1beta, interferon-gamma) were assessed by ELISA, and nitric oxide (NO) production was evaluated by Griess assay. Nuclear factor (NF)-kappaB p65 subunit, inhibitor of NFkappaB-alpha, and p38 mitogen-activated protein kinase (MAPK) were assessed by immunoblotting. Arg(high)/Gln(high) decreased the production of TNFalpha, IL-1beta, IL-8, and IL-6 (each P < 0.01). Arg(low)/Gln(high) decreased IL-6 and IL-8 production (both P < 0.01), whereas Arg(high)/Gln(low) did not affect cytokine and NO production. Arg(low)/Gln(high) and Arg(high)/Gln(high) decreased NF-kappaB p65 subunit expression, whereas p38 MAPK was decreased only by Arg(high)/Gln(high). Combined pharmacological doses of Arg and Gln decreased TNFalpha and the main proinflammatory cytokines release in active colonic CD biopsies via NF-kappaB and p38 MAPK pathways. These results could be the basis of prospective studies evaluating the effects of enteral supply of combined Arg and Gln during active CD.

Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor that regulates intestinal inflammation. PPAR gamma is highly expressed in the colon and can be activated by various dietary ligands. A number of fatty acids such as polyunsaturated fatty acids or eicosanoids are considered as endogenous PPAR gamma activators. Nevertheless, other nutrients such as glutamine, spicy food or flavonoids are also able to activate PPAR gamma. As PPAR gamma plays a key role in bacterial induced inflammation, anti-inflammatory properties of probiotics may be mediated through PPAR gamma. The aims of the present review are to discuss of the potential roles of dietary compounds in modulating intestinal inflammation through PPAR gamma.

International audience

Inflammation is a protective process for life that aims to restore body homeostasis by targeting the injury and by inducing repair mechanisms. This process can also become excessive and lead to chronic inflammation and organ fibrosis. Polyunsaturated fatty acids play a key role in inflammatory processes and their resolution. Indeed, numerous lipid mediators derived from n-3 or n-6 PUFA such as eicosanoids, endocannabinoids, or proresolving lipids are able to target transcription factors to modulate gene expression. One other important action mechanism is by modification of cell membrane composition. The purpose of the present review is to describe the potential mechanisms by which PUFA influence inflammatory processes. To illustrate this purpose, we focused on the interactions between PUFA and intestinal inflammation as an integrative example.

The ubiquitin proteasome system (UPS) is the major pathway of intracellular protein degradation and may be involved in the pathophysiology of inflammatory bowel diseases or irritable bowel syndrome. UPS specifically degrades proteins tagged with an ubiquitin chain. We aimed to identify polyubiquitinated proteins during inflammatory response in intestinal epithelial HCT-8 cells by a proteomic approach. HCT-8 cells were incubated with interleukin 1β, tumor necrosis factor-α, and interferon-γ for 2 h. Total cellular protein extracts were separated by 2D gel electrophoresis and analyzed by an immunodetection using antiubiquitin antibody. Differential ubiquitinated proteins were then identified by LC-ESI MS/MS. Seven proteins were differentially ubiquitinated between control and inflammatory conditions. Three of them were chaperones: Grp75 and Hsc70 were more ubiquitinated (p < 0.05) and Grp78 was less ubiquitinated (p < 0.05) under inflammatory conditions. The results for Grp75 and Grp78 were then confirmed in HCT-8 cells and in 2-4-6-trinitrobenzen sulfonic acid induced colitis in rats mimicking inflammatory bowel disease by immunoprecipitation. No difference was observed in irritable bowel syndrome like model. In conclusion, we showed that a proteomic approach is suitable to identify ubiquitinated proteins and that UPS-regulated expression of Grp75 and Grp78 may be involved in inflammatory response. Further studies should lead to the identification of ubiquitin ligases responsible for Grp75 and Grp78 ubiquitination.

During nutrient deprivation, autophagy provides the constituents required to maintain the metabolism essential for survival. Recently, genome-wide association studies have identified genetic determinants for susceptibility to Crohn's disease (CD) such as ATG16L1 and IRGM that are involved in the autophagy pathway. Both disease-carrying NOD2 mutations and ATG16L1 mutations may result in impairment of autophagy. Impairment in autophagy results in impaired clearance of microbes. Ileal CD is associated with Paneth cell loss of function such as decreased production of α-defensins, which may arise from mutations in NOD2 or autophagy genes. Nutrients are able to modify several cellular pathways and in particular autophagy. We summarize the contribution of a variety of dietary components to activate autophagy. Understanding the crosstalk between nutrients and autophagy in the intestine may provide novel targets that have therapeutics potential in intestinal inflammation. Nutrient activation of autophagy may contribute to restoring the Paneth cell loss of function in ileal CD.

Magnetic resonance colonography (MRC) has been recently developed to assess bowel inflammation in inflammatory bowel disease (IBD) patients. Evaluating animal models of inflammation with MRC may be important in new drug-screening processes. The aim of this study was to assess the feasibility of MRC in colitic rats and confront it with model characteristics.Colitis was induced by rectal injection of trinitrobenzene-sulfonic acid (TNBS) in 13 rats while six rats received the vehicle. MRC was performed at day 2. Colon inflammation and production of inflammatory mediators were evaluated. Image quality was assessed by wall and motion artifacts. MRC criteria were bowel wall thickness, wall signal intensity on T2-weighted (T2w) and T1w images, the appearance of a target sign pattern, and irregular patterns of mucosal surface.MRC quality was good or excellent in 16/21 examinations with no difference between groups. Colitis rats were significantly different from controls in terms of wall thickness (P = 0.004), the appearance of a target sign pattern (P = 0.02), irregular patterns of mucosal surface (P = 0.01), and hyperintensity on T1w images (P = 0.03). All MRC criteria except maximal bowel wall thickness were associated with colon weight:length ratio and inflammatory biomarkers (all P0.05). Minimal bowel wall thickness and wall signal intensity on T2w images were associated with histological score (P0.05).MRC is feasible and reliable in rats with TNBS-induced colitis. MRC criteria including colon wall thickness, wall signal intensity on T2w images, hyperintensity in T1w sequence, and the appearance of a target sign pattern may be potential targets for new IBD drugs.

5-aminosalicylic acid (5-ASA) is widely used for the treatment of inflammatory bowel disease (IBD). Recent studies have evaluated the potential of nutritional intervention as adjunct therapy to 5-ASA in IBD. N-3 polyunsaturated fatty acids (PUFA) have shown potent anti-inflammatory properties in gut inflammation. Therefore, we aimed to evaluate the efficacy of the dual therapy (n-3 PUFA plus 5-ASA) in rats with 2, 4, 6-trinitrobenzen sulfonic acid (TNBS)-induced colitis. Colitis was induced by intrarectal injection of TNBS while control rats received the vehicle. Rats received by gavage a fish oil-rich formula (n-3 groups) or an isocaloric and isolipidic oil formula supplemented with 5-ASA for 14 days. A dose response of 5-ASA (5-75 mg. suppression mg kg(-1) d(-1)) was tested. Colitis was evaluated and several inflammatory markers were quantified in the colon. COX-2 expression (P

The role of endothelial cells in inflammatory bowel disease has been recently emphasized. Endothelial activation and expression of adhesion molecules are critical for leukocytes recruitment into the inflammatory wall. Compelling evidence demonstrated anti-inflammatory effects of long chain n-3 PUFA in inflammatory models. We previously showed that long chain n-3 PUFA (EPA and DHA) inhibited inflammatory response in epithelial and dendritic cells. As long chain n-3 PUFA treatment led to a decreased expression of adhesion molecules in endothelial cells from other organs, we have now investigated their effect on intestinal endothelial cells in vitro and in colitic rats.In vitro study: Primary culture of human intestinal microvascular endothelial cells (HIMEC) were pre-treated with DHA and then incubated with IL-1β. In vivo study: Colitis was induced in 2 groups at day0 by intrarectal injection of 2-4-6-trinitrobenzen sulfonic acid (TNBS). Rats received by gavage either fish oil, rich in EPA and DHA (TNBS+n-3) or an isocaloric isolipidic oil formula for 14 days.DHA led to a decreased VCAM-1, TLR4, cyclooxygenase-2 and VEGFR2 expression and a decreased production of IL-6, IL-8 and GM-CSF and a reduced production of PGE(2) and LTB(4) (p 0.001) in IL-1β-induced HIMEC. Similarly, dietary intervention with fish oil rich in EPA and DHA significantly decreased colon production of PGE(2) and LTB(4,) endothelial VCAM-1 and VEGFR2 in rats with colitis.Data obtained from in vitro and in vivo studies reveal a potential anti-angiogenic role of long chain n-3 PUFA in intestinal endothelial cells. This protective effect of long chain n-3 PUFA may partly explain the observed benefit of dietary intake of long chain n-3 PUFA in IBD development.

Introduction et but de l’etude Le systeme ubiquitine-proteasome, systeme de degradation proteique majeur, est implique dans la regulation de nombreux processus cellulaires et dans la reponse inflammatoire intestinale. Des effets protecteurs de la glutamine au niveau intestinal ont ete decrits dans diverses situations physiopathologiques. La glutamine modifie la degradation de l’inhibiteur du facteur de transcription NF-kB par le proteasome en regulant son processus d’ubiquitination. Cependant, les effets de la glutamine sur le processus d’ubiquitination d’autres proteines restent meconnus. Le but de cette etude etait donc de rechercher les proteines dont le taux d’ubiquitination etait modifie par la glutamine au cours d’une colite chez le rat. Materiel et methodes Des rats mâles Sprague Dawley ont ete repartis en 3 groupes (n = 8 / groupe). Une colite a ete induite par une injection rectale d’une solution de TNBS au jour 1. Une injection intra-rectale de glutamine (25 mg kg −1 , 3 ml, TNBS/Gln) ou de PBS (3 ml, TNBS/PBS) a ensuite ete realisee chaque jour de J2 a J6. A J7, les rats ont ete euthanasies et des segments coliques ont ete preleves. L’expression des proteines ubiquitinees a ete etudiee par une approche proteomique combinant une electrophorese bidimensionnelle et un immunoblot dirige contre l’ubiquitine. Apres analyse des variations d’ubiquitination (basee sur un ratio d’expression R > 1,5), les proteines d’interet ont ete identifiees par spectrometrie de masse. Des cytokines pro-inflammatoires (TNFα, IL-1β) ont egalement ete mesurees. Resultats et Analyse statistique Le taux de survie etait signifi-cativement augmente dans le groupe TNBS/Gln par rapport au groupe TNBS/PBS (8/8 vs 5/8, p Conclusion Nos resultats suggerent donc que la glutamine peut moduler le taux d’ubiquitination de proteines au cours d’une reponse inflammatoire intestinale chez le rat, en particulier de proteines impliquees dans la production d’ATP. Des etudes complementaires devront etre menees pour mieux comprendre les mecanismes d’action de la glutamine sur le systeme ubiquitine-pro-teasome et pour savoir si ces effets sont impliques dans les proprietes anti-inflammatoires de la glutamine.

Background Peroxisome proliferator-activated receptor gamma (PPARgamma) plays a role in the regulation of intestinal inflammation and is activated by both natural (polyunsaturated fatty acid; PUFAs) and synthetic (troglitazone) ligands. The fatty acid content of defined formula diets may play a role in mediating the antiinflammatory effect, but the mechanism is unclear. Objective We evaluated to what extent the effect of PUFAs on intestinal inflammation is mediated via PPARgamma. Design The human enterocyte-like cell line Caco-2 and human dendritic cells were stimulated by interleukin (IL) 1beta and lipoprotein polysaccharide, respectively, in the presence of PPARgamma agonists (troglitazone or PUFAs) or antagonist (GW9662). Five PUFAs were tested: alpha-linolenic acid (ALA), conjugated linoleic acid (CLA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and gamma-linolenic acid (GLA). Cytokine production was measured by enzyme-linked immunosorbent assay and PPARgamma, I-kappaB, and inducible nitric oxide synthase (iNOS) expression by Western blot. Results In Caco-2 cells, IL-6 secretion was significantly decreased by troglitazone, DHA, EPA, and GLA. IL-8 production was significantly decreased by troglitazone, ALA, DHA, EPA, and GLA. PPARgamma expression was significantly increased by troglitazone, DHA, and EPA. iNOS expression was significantly decreased by troglitazone, DHA, and EPA. Troglitazone and PUFAs at 0.1 mumol/L tended to increase the expression of I-kappaB. Addition of GW9662 reversed the effect of troglitazone and PUFAs at 0.1 mumol/L on IL-8 production and decreased the expression of PPARgamma. EPA and DHA also modulated the dendritic cell response to lipoprotein polysaccharide. Conclusions The tested PUFAs exerted an antiinflammatory effect in vitro in both models. This effect of PUFAs in Caco-2 cells is similar to that of troglitazone on intestinal inflammation mediated by PPARgamma, and the potency of the antiinflammatory effect is linked to the number of double bonds.

International audience; Glutamine plays a key role in the metabolism of rapidly dividing cells, including enterocytes and lymphocytes, which may contribute to its beneficial clinical effects. Gut mucosal homeostasis is achieved through a balance between cell proliferation and apoptosis. In T cells, glutamine up-regulates antiapoptotic proteins and down-regulates proapoptotic proteins. In gut mucosa, glutamine prevents apoptosis in rat epithelial cell lines, whereas glutamine starvation induces apoptosis through caspase activation. Finally glutamine specifically prevents tumor necrosis factor-alpha-related apoptosis in the human intestinal cell line HT-29. Comparative functional proteomics enables the characterization of each differentially expressed protein in intestinal cells in response to modifications of nutritional environment. The influence of glutamine on intestinal proteome expression in apoptotic conditions has not been studied and evaluated. This comparative proteomics study was performed in the human epithelial intestinal cell line HCT-8 under experimental apoptotic conditions to investigate the influence of glutamine on protein expression during apoptosis. The pharmaconutritional effects of glutamine were determined under 2 mm (physiological concentration) and 10 mm (pharmaconutritional concentration) conditions. About 1,800 protein spots were revealed in both conditions. Comparative assessments indicated that 28 proteins were differentially expressed significantly (i.e. at least 2-fold modulated and Student's t test with p

Introduction et but de l’etude La supplementation en acides gras polyinsatures omega-3 pourrait etre benefique au cours de l’inflammation intestinale mais est souvent limitee en clinique par la mauvaise tolerance digestive des huiles de poisson. Le but de cette etude est de tester l’efficacite d’une nouvelle formulation developpee par notre laboratoire, fortement concentree en ω3 d’origine vegetale nanoencapsules, sur un modele de colite inflammatoire, et d’en preciser les mecanismes d’action. Materiel et methodes 24 rats mâles Sprague-Dawley ont ete repartis en 3 groupes (controle, TNBS et TNBS/ω3). Les groupes TNBS et TNBS/ω3 ont recu une injection intra-rectale d’une solution de TNBS/ethanol (50 %) a J0 pour induire une colite alors que le groupe controle n’a recu que de l’ethanol (50 %). L’alimentation a ete supplementee soit en ω3 (450 mg/kg/j, groupe TNBS/ ω3), soit en huile de mais (groupes controle et TNBS) de J-7 a J+7, le jour de sacrifice. Tous les regimes alimentaires etaient isocaloriques. La masse corporelle, la prise hydrique et alimentaire ont ete suivies quotidiennement. Les taux des ARNm du TNFα et de l’IL-1 s ont ete mesures par PCR en temps reel. L’expression colique de mediateurs inflammatoires (COX-2, iNOS, PPARγ, p-JNK, p-P38) a ete determinee par western blot. La production intra-muqueuse colique en PGE2 et LTB4 a ete mesuree par ELISA. Des prelevements de sang au moment du sacrifice ont ete effectues afin d’etudier le profil en acides gras ω3 erythrocytaire par chro-matographie gazeuse. Resultats Le poids et la prise alimentaire des rats TNBS et TNBS/ω3 sont reduits par rapport aux rats controles. Une augmentation du rapport poids/longueur du colon a ete constatee chez les rats TNBS et TNBS/ω3 (0,57 et 0.52 vs 0,18, p 0,05). Le meme profil de reponse a ete observe pour les PGE2 et les ARNm d’IL-1s. L’expression proteique de COX2 et d’iNOS est significativement augmentee chez les rats TNBS par rapport aux controles (p Conclusions Ces resultats suggerent un effet antiinflammatoire intestinal de la supplementation avec la nouvelle formulation d’omega-3, qui est bien biodisponible.

To investigate whether targeting proteasome might reverse intestinal fibrosis in rats.Chronic colitis was induced in rats by repeated administration of increasing dose of 2,4,6-trinitrobenzene sulfonic acid (TNBS, 15, 30, 45, 60, 60, 60 mg) by rectal injection for 6 wk (from day 0 to day 35), while control rats received the vehicle. TNBS + bortezomib (BTZ) rats received intraperitoneal injections of BTZ twice weekly (from day 37 to day 44) at a dose of 25 mg/kg, whereas the control and TNBS groups received the same amount of the vehicle. Histologic scoring of inflammation and fibrosis was performed. Colonic production of transforming growth factor (TGF)-β was measured by ELISA. Colon fibrosis-related proteins such as phospho-p38, phospho-SMAD2/3, Akt and peroxisome proliferator activated receptor γ (PPARγ) were studied by western blot. Expression of the tight junction proteins, occludin and claudin-1, were assessed by Western blot. Colon proteasome activities (chymotrypsin-like and trypsin-like activities) were assessed.TNBS-treated rats had a higher colon weight/length ratio compared to control rats (P0.01). Furthermore, fibrosis and inflammation scores were higher in TNBS-treated rats compared to control rats (P0.01 for both). Colonic production of TGF-β production tended to be higher in TNBS-treated rats (P0.06). Fibrosis-related proteins such as phospho-p38, phospho-SMAD2/3, and PPARγ were significantly higher in TNBS-treated rats compared to control rats (all P0.05). TNBS rats had a higher expression of Akt compared to control rats (P0.01). Tight junction proteins were modified by repeated TNBS challenge: colon occludin expression rose significantly (P0.01), whereas claudin-1 expression fell (P0.01). Bortezomib inhibition significantly decreased chymotrypsin-like activity (P0.05), but had no significant effect on trypsin-like activity (P0.05). In contrast, bortezomib had no effect on other studied parameters such as fibrosis score, TGF-β signaling, or tight junction expression (P0.05 for all).Rats with TNBS-induced chronic colitis exhibited colon fibrosis associated with higher TGF-β signaling. Proteasome inhibition by bortezomib had no effect on fibrosis in our experimental conditions.

Introduction et but de l’etude L’arginine et la glutamine sont deux acides amines conditionnellement essentiels qui ont montre des proprietes immuno-modulatrices. Neanmoins, les etudes evaluant leurs effets au cours des maladies inflammatoires chroniques de l’intestin, maladie de Crohn (MC) et rectocolite hemorragique, sont encore limitees et peu concluantes. Le but de cette etude a donc ete d’evaluer les effets de l’arginine et de la glutamine, seules ou combinees, sur la production de cytokines et de NO par des biopsies coliques prelevees chez des patients atteints de la MC en poussee et mises en culture d’explants. Materiel et methodes Dix patients atteints de MC en poussee (CDAI > 150) ont ete inclus. Au cours d’une endoscopie de suivi, 8 biopsies coliques ont ete prelevees en zone pathologique et mises en culture pendant 18 heures. Quatre conditions d’incubation ont ete testees, apportant des doses (mM) physiologiques ou pharmacologiques d’arginine (0,1 ou 2) et de glutamine (0,6 ou 10). La production de cytokines et de NO dans le milieu de culture a ete ensuite etudiee, respectivement, par ELISA et par la reaction de Griess. Apres extraction des proteines a partir des biopsies, l’expression de la p38 MAPK, de la sous unite p65 NF k B et d’I k Bα a ete mesuree par western-blot. Les resultats (moyenne ± sem) ont ete compares par une analyse de variance non parametrique pour series appariees (Test de Friedman) suivie du post-test de Wilcoxon. Le seuil de significativite a ete fixe a p Resultats La glutamine seule ou associee a l’arginine diminue la production d’IL-8 et d’IL-6 (p Conclusions La glutamine seule diminue la production d’IL-8 et d’IL-6 mais la combinaison de fortes doses d’arginine et de glutamine semble etre la plus efficace pour reduire la production des cytokines pro-inflammatoires par des biopsies coliques de patients atteints de la MC, sans influencer la production de NO. La voie NFkB et la voie p38 MAPK pourraient medier ces effets. Ces resultats justifient l’evaluation d’une association d’arginine et de glutamine chez des patients atteints de MC.