Translation of the nine item avoidant/restrictive food intake disorder screen (NIAS) questionnaire in French (NIAS-Fr).

BACKGROUND: The Nine Item Avoidant/Restrictive Food Intake Disorder (ARFID) Screen (NIAS) questionnaire is originally available in English. Given the significant overlap of ARFID-like symptoms in gastrointestinal (GI) diseases, ARFID screening becomes crucial in these patient populations. Consequently, the translation of the NIAS questionnaire into French is necessary for its utilization in French-speaking countries. METHODS: Clinical experts in neuro-gastroenterology and dietetics from four medical centres in two French-speaking countries (France and Belgium) took part in a well-structured questionnaire translation procedure. This process involved six steps before final approval: translation from English to French, backward translation, comparison between the original and retranslated versions, testing the translated version on patients, making corrections based on patient feedback, and testing the corrected version on an additional sample of patients. KEY RESULTS: The NIAS questionnaire in French (NIAS-Fr) was tested on 18 outpatients across the involved centres. For the majority of native French-speaking patients, the translated questionnaire was well understood and clear. After incorporating two relevant modifications suggested by the patients, the translated questionnaire was approved through testing on an additional sample of patients. CONCLUSIONS AND INFERENCES: The involvement of two French-speaking countries was crucial for the harmonization and cultural adaptation of the questionnaire. As a result, the NIAS-Fr is now available for use in 54 French-speaking countries, serving approximately 321 million French speakers across five continents for screening ARFID, for both clinical and research purposes.

Crohn's disease: Why the ileum?

Crohn's disease (CD) is an inflammatory bowel disease characterized by immune-mediated flares affecting any region of the intestine alternating with remission periods. In CD, the ileum is frequently affected and about one third of patients presents with a pure ileal type. Moreover, the ileal type of CD presents epidemiological specificities like a younger age at onset and often a strong link with smoking and genetic susceptibility genes. Most of these genes are associated with Paneth cell dysfunction, a cell type found in the intestinal crypts of the ileum. Besides, a Western-type diet is associated in epidemiological studies with CD onset and increasing evidence shows that diet can modulate the composition of bile acids and gut microbiota, which in turn modulates the susceptibility of the ileum to inflammation. Thus, the interplay between environmental factors and the histological and anatomical features of the ileum is thought to explain the specific transcriptome profile observed in CD ileitis. Indeed, both immune response and cellular healing processes harbour differences between ileal and non-ileal CD. Taken together, these findings advocate for a dedicated therapeutic approach to managing ileal CD. Currently, interventional pharmacological studies have failed to clearly demonstrate distinct response profiles according to disease site. However, the high rate of stricturing disease in ileal CD requires the identification of new therapeutic targets to significantly change the natural history of this debilitating disease.

Dietary AhR Ligands Have No Anti-Fibrotic Properties in TGF-ß1-Stimulated Human Colonic Fibroblasts.

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-ß1-stimulated human colonic fibroblast cells. METHODS: The study was conducted using TGF-ß1-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-ß1 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-ß1-induced CCD-18Co. CONCLUSIONS: Our data highlight that none of the tested dietary AhR ligands had an effect on fibrosis markers in TGF-ß1-stimulated human colonic fibroblast cells in our experimental conditions. Further studies are now required to identify novel potential targets in intestinal fibrosis.

Gut Microbiota, Macrophages and Diet: An Intriguing New Triangle in Intestinal Fibrosis.

Intestinal fibrosis is a common complication in inflammatory bowel disease (IBD) without specific treatment. As macrophages are the key actors in inflammatory responses and the wound healing process, they have been extensively studied in chronic diseases these past decades. By their exceptional ability to integrate diverse stimuli in their surrounding environment, macrophages display a multitude of phenotypes to underpin a broad spectrum of functions, from the initiation to the resolution of inflammation following injury. The hypothesis that distinct macrophage subtypes could be involved in fibrogenesis and wound healing is emerging and could open up new therapeutic perspectives in the treatment of intestinal fibrosis. Gut microbiota and diet are two key factors capable of modifying intestinal macrophage profiles, shaping their specific function. Defects in macrophage polarisation, inadequate dietary habits, and alteration of microbiota composition may contribute to the development of intestinal fibrosis. In this review, we describe the intriguing triangle between intestinal macrophages, diet, and gut microbiota in homeostasis and how the perturbation of this discreet balance may lead to a pro-fibrotic environment and influence fibrogenesis in the gut.

Magnetic resonance colonography assessment of acute trinitrobenzene sulfonic acid colitis in pre-pubertal rats.

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 ß2 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 1ß, 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.

Diet in Intestinal Fibrosis: A Double-Edged Sword.

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.

Dietary salt exacerbates intestinal fibrosis in chronic TNBS colitis via fibroblasts activation.

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.

A polymeric diet rich in transforming growth factor beta 2 does not reduce inflammation in chronic 2,4,6-trinitrobenzene sulfonic acid colitis in pre-pubertal rats.

BACKGROUND: Pediatric Crohn's disease is characterized by a higher incidence of complicated phenotypes. Murine models help to better understand the dynamic process of intestinal fibrosis and test therapeutic interventions. Pre-pubertal models are lacking. We aimed to adapt a model of chronic colitis to pre-pubertal rats and test if a polymeric diet rich in TGF-ß2 could reduce TNBS-induced intestinal inflammation and fibrosis. METHODS: Colitis was induced in 20 five-week-old Sprague-Dawley male rats by weekly rectal injections of increasing doses of TNBS (90 mg/kg, 140 mg/kg and 180 mg/kg) for 3 weeks, while 10 controls received phosphate-buffered saline. Rats were anesthetized using ketamine and chlorpromazine. After first administration of TNBS, 10 rats were fed exclusively MODULEN IBD® powder, while remaining rats were fed breeding chow. Colitis was assessed one week after last dose of TNBS by histopathology and magnetic resonance colonography (MRC). RESULTS: Histological inflammation and fibrosis scores were higher in TNBS group than controls (p < 0.05 for both). MRC showed increased colon wall thickness in TNBS group compared to controls (p < 0.01), and increased prevalence of strictures and target sign (p < 0.05). Colon expression of COL1A1, CTGF, α-SMA and COX-2 did not differ between TNBS rats and controls. TNBS colitis was not associated with growth failure. Treatment with MODULEN IBD® was associated with growth failure, increased colon weight/length ratio (p < 0.01), but did not affect histological scores or MRI characteristics. Colon expression of α-SMA was significantly lower in the MODULEN group versus controls (p = 0.005). CONCLUSION: Features of chronic colitis were confirmed in this model, based on MRC and histopathology. Treatment with MODULEN did not reverse inflammation or fibrosis.

Modeling undernutrition with enteropathy in mice.

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.

Animal Models of Undernutrition and Enteropathy as Tools for Assessment of Nutritional Intervention.

: 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 and Food Additives: To Add Fuel on the Flames!

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.

Chronic colitis-induced visceral pain is associated with increased anxiety during quiescent phase.

Inflammatory bowel diseases (IBD) are characterized by repetition of flares and remission periods leading to chronic postinflammatory sequelae. Among postinflammatory sequelae, one-third of patients with IBD are suffering from functional symptoms or psychological comorbidities that persist during remission. The aim of our study was to assess functional and behavioral sequelae of chronic colitis in rats with quiescent intestinal inflammation. Chronic colitis was induced by a weekly intrarectal injection of increasing concentrations of trinitrobenzene sulfonic acid (TNBS) for 3 wk (15-45 mg of TNBS) in 30 rats, whereas the control rats (n = 24) received the vehicle. At 50 days post-TNBS, visceral sensitivity was assessed by visceromotor response to colorectal distension, and transient receptor potential vanilloid type 1 (TRPV1) expression was also quantified in the colon and dorsal root ganglia. Barrier function and inflammatory response were assessed by studying intestinal permeability, tight junction protein, myeloperoxidase activity, histological score, and cytokine production (IL-6, IL-10, and TNF-α). Anxiety behavioral tests were performed from 50 to 64 days after the last TNBS injection. Chronic TNBS induced 1) a visceral hypersensitivity (P = 0.03), 2) an increased colon weight-to-length ratio (P = 0.01), 3) higher inflammatory and fibrosis scores (P = 0.0390 and P = 0.0016, respectively), and 4) a higher colonic IL-6 and IL-10 production (P = 0.008 and P = 0.005, respectively) compared with control rats. Intestinal permeability, colonic production of TNF-α, myeloperoxidase activity, and TRPV1 expression did not differ among groups. Chronic TNBS increased anxiety-related behavior in the open-field test and in the acoustic stress test. In conclusion, chronic colitis induced functional sequelae such as visceral hypersensitivity and increased anxiety with a low-grade intestinal inflammation. Development of a representative animal model will allow defining novel therapeutic approaches to achieve a better management of IBD-related sequelae. NEW & NOTEWORTHY Patients with inflammatory bowel diseases have impaired quality of life. Therapeutic progress to control mucosal inflammation provides us an opportunity to develop novel approaches to understand mechanisms behind postinflammatory sequelae. We used a chronic colitis model to study long-term sequelae on visceral pain, gut barrier function, and psychological impact. Chronic colitis induced functional symptoms and increased anxiety in the remission period. It might define novel therapeutic approaches to achieve a better inflammatory bowel disease-related sequelae management.

Dietary n-3 PUFA May Attenuate Experimental Colitis.

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 TNFα production (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.

SPECT-computed tomography in rats with TNBS-induced colitis: A first step toward functional imaging.

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.

IBD: In Food We Trust.

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.

Fatty acids, eicosanoids and PPAR gamma.

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.

Polyunsaturated fatty acids and inflammation.

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.

Glutamine enema regulates colonic ubiquitinated proteins but not proteasome activities during TNBS-induced colitis leading to increased mitochondrial activity.

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-1ß 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.

Magnetic resonance colonography for fibrosis assessment in rats with chronic colitis.

BACKGROUND: Magnetic resonance colonography (MRC) has been developed to assess inflammatory bowel diseases. We aimed to assess the feasibility of MRC in rats with TNBS-induced chronic colitis and to confront imaging results with fibrosis and stenosing features of the model. MATERIALS AND METHODS: Chronic colitis was induced in 12 rats by weekly intra-rectal injection of increasing doses of TNBS for 6 weeks, while 8 control rats received the vehicle. At week 7, MRC was performed. Fibrosis scores were assessed and fibrosis mediators measured. RESULTS: Chronic colitis was associated with significant body weight loss (p<0.0001) and higher colon weight/length compared to controls (p = 0.0004). Fibrosis mediators and histological scores were significantly higher in rats with TNBS than in controls: α-SMA expression (0.9 versus 0.61, p = 0.0311) and fibrosis score (p = 0.0308). Colon wall thickness was higher in rats with TNBS than in controls: maximal thickness (2.38 versus 0.74 mm, p<0.0001) and minimal thickness (1.33 versus 0.48 mm, p<0.0001). Wall signal intensity on T2w images was higher in rats with TNBS than in controls (9040 versus 6192, p = 0.0101) and correlated with fibrosis score (r = 0.5214; p = 0.04). Luminal narrowing was higher in rats with TNBS (50.08 versus 10.33%, p<0.0001) and correlated with α-SMA expression (r = 0.5618; p = 0.01). Stenosis was observed in 7/9 rats with TNBS and in no controls (p = 0.0053). CONCLUSIONS: MRC is feasible and easily distinguishes rats with colitis from controls. MRC signs correlated with fibrosis parameters. MRC evaluation may be part of a new anti-fibrosis drug assessment in experimental models of chronic colitis.

2,4,6-trinitrobenzene sulfonic acid-induced chronic colitis with fibrosis and modulation of TGF-ß1 signaling.

AIM: To investigate whether targeting proteasome might reverse intestinal fibrosis in rats. METHODS: 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)-ß 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. RESULTS: TNBS-treated rats had a higher colon weight/length ratio compared to control rats (P < 0.01). Furthermore, fibrosis and inflammation scores were higher in TNBS-treated rats compared to control rats (P < 0.01 for both). Colonic production of TGF-ß production tended to be higher in TNBS-treated rats (P < 0.06). Fibrosis-related proteins such as phospho-p38, phospho-SMAD2/3, and PPARγ were significantly higher in TNBS-treated rats compared to control rats (all P < 0.05). TNBS rats had a higher expression of Akt compared to control rats (P < 0.01). Tight junction proteins were modified by repeated TNBS challenge: colon occludin expression rose significantly (P < 0.01), whereas claudin-1 expression fell (P < 0.01). Bortezomib inhibition significantly decreased chymotrypsin-like activity (P < 0.05), but had no significant effect on trypsin-like activity (P > 0.05). In contrast, bortezomib had no effect on other studied parameters such as fibrosis score, TGF-ß signaling, or tight junction expression (P > 0.05 for all). CONCLUSION: Rats with TNBS-induced chronic colitis exhibited colon fibrosis associated with higher TGF-ß signaling. Proteasome inhibition by bortezomib had no effect on fibrosis in our experimental conditions.