Control of anterior GRadient 2 (AGR2) dimerization links endoplasmic reticulum proteostasis to inflammation

International audienceAnterior gradient 2 (AGR2) is a dimeric protein disulfide isomerase family member involved in the regulation of protein quality control in the endoplasmic reticulum (ER). Mouse AGR2 deletion increases intestinal inflammation and promotes the development of inflammatory bowel disease (IBD). Although these biological effects are well established, the underlying molecular mechanisms of AGR2 function toward inflammation remain poorly defined. Here, using a protein-protein interaction screen to identify cellular regulators of AGR2 dimerization, we unveiled specific enhancers, including TMED2, and inhibitors of AGR2 dimerization, that control AGR2 functions. We demonstrate that modulation of AGR2 dimer formation, whether enhancing or inhibiting the process, yields pro-inflammatory phenotypes, through either autophagy-dependent processes or secretion of AGR2, respectively. We also demonstrate that in IBD and specifically in Crohn's disease, the levels of AGR2 dimerization modulators are selectively deregulated, and this correlates with severity of disease. Our study demonstrates that AGR2 dimers act as sensors of ER homeostasis which are disrupted upon ER stress and promote the secretion of AGR2 monomers. The latter might represent systemic alarm signals for pro-inflammatory responses

Suivi à long terme d'une cohorte de patients atteints de maladie de Crohn ayant interrompu l'azathioprine après une rémission prolongée

Introduction : après rémission par azathioprine (AZA) dans la maladie de Crohn (MC), la durée optimale du traitement reste inconnue. Le GETAID a mené un essai contrôlé randomisé (ECR) multicentrique comparant l'arrêt de l'AZA à sa poursuite après au moins 3.5 ans de rémission. A 18 mois, les taux de rechute étaient de 21.3 % (groupe placebo) et 7.9 % (groupe AZA). Un suivi a été réalisé afin de préciser le devenir à plus long terme de cette cohorte. Malades et méthodes : 83 patients étaient inclus dans l'ECR entre octobre 1995 et novembre 1999. Après randomisation, 43 avaient été mis sous placebo à l'inclusion. Parmi les 37 patients (sur 40 inclus) qui ont suivi le traitement par AZA, 23 l'ont arrêté après les 18 mois de l'essai. La cohorte de l'étude actuelle comprend donc 66 patients ayant interrompu l'AZA, 29 hommes et 37 femmes, âgés de 39 12 ans (m SD), traités par AZA depuis 74 28 mois, en rémission clinique depuis 67 25 mois. Après clôture de l'ECR, un suivi a été réalisé jusqu'en janvier 2003. Le critère de jugement principal était la survenue d'une rechute définie par l'association d'un score de Harvey-Bradshaw 4 et la reprise d'un traitement (en dehors des salicylés). Résultats : Le suivi médian était de 54.5 6.4 mois après arrêt de l'AZA. 32/66 malades ont présenté une rechute après l'arrêt du traitement. Les taux de rechute selon la méthode de Kaplan-Meier étaient de 14.0 4.3 % à 1 an, 52.8 7.1 % à 3 ans et 62.6 7.2 % à 5 ans. Parmi les 32 patients qui ont rechuté après arrêt de l'AZA, 23 ont de nouveau reçu de l'AZA, avec succès pour 22 d'entre eux (96 %). Le seul échec du retraitement par AZA est survenu chez un patient souffrant de lésions anopérinéalesPARIS7-Xavier Bichat (751182101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Systemically delivered adipose stromal vascular fraction mitigates radiation-induced gastrointestinal syndrome by immunomodulating the inflammatory response through a CD11b+ cell-dependent mechanism

International audienceBackground Stromal vascular fraction (SVF) treatment promoted the regeneration of the intestinal epithelium, limiting lethality in a mouse model of radiation-induced gastrointestinal syndrome (GIS). The SVF has a heterogeneous cell composition; the effects between SVF and the host intestinal immunity are still unknown. The specific role of the different cells contained in the SVF needs to be clarified. Monocytes-macrophages have a crucial role in repair and monocyte recruitment and activation are orchestrated by the chemokine receptors CX3CR1 and CCR2. Methods Mice exposed to abdominal radiation (18 Gy) received a single intravenous injection of SVF (2.5 × 10 6 cells), obtained by enzymatic digestion of inguinal fat tissue, on the day of irradiation. Intestinal immunity and regeneration were evaluated by flow cytometry, RT-PCR and histological analyses. Results Using flow cytometry, we showed that SVF treatment modulated intestinal monocyte differentiation at 7 days post-irradiation by very early increasing the CD11b + Ly6C + CCR2 + population in the intestine ileal mucosa and accelerating the phenotype modification to acquire CX3CR1 in order to finally restore the F4/80 + CX3CR1 + macrophage population. In CX3CR1-depleted mice, SVF treatment fails to mature the Ly6C − MCHII + CX3CR1 + population, leading to a macrophage population deficit associated with proinflammatory environment maintenance and defective intestinal repair; this impaired SVF efficiency on survival. Consistent with a CD11b + being involved in SVF-induced intestinal repair, we showed that SVF-depleted CD11b + treatment impaired F4/80 + CX3CR1 + macrophage pool restoration and caused loss of anti-inflammatory properties, abrogating stem cell compartment repair and survival. Conclusions These data showed that SVF treatment mitigates the GIS-involving immunomodulatory effect. Cooperation between the monocyte in SVF and the host monocyte defining the therapeutic properties of the SVF is necessary to guarantee the effective action of the SVF on the GIS

Why is SARS-CoV-2 infection more severe in obese men? The gut lymphatics – Lung axis hypothesis

International audienceConsistent observations report increased severity of SARS-CoV-2 infection in overweight men with cardiovascular factors. As the visceral fat possesses an intense immune activity, is involved in metabolic syndrome and is at the crossroad between the intestines, the systemic circulation and the lung, we hypothesized that it plays a major role in severe forms of SARS-CoV-2 infection. SARS-CoV2 presents the ability to infect epithelial cells of the respiratory tract as well as the intestinal tract. Several factors may increase intestinal permeability including direct enterocyte damage by SARS-CoV2, systemic inflammatory response syndrome (SIRS) and epithelial ischemia secondary to SARS-CoV2- associated endothelial dysfunction. This increase permeability further leads to translocation of microbial components such as MAMPs (microbial-associated molecular pattern), triggering an inflammatory immune response by TLR-expressing cells of the mesentery fat (mostly macrophages and adipocytes). The pro-inflammatory cytokines produced by the mesentery fat mediates systemic inflammation and aggravate acute respiratory distress syndrome (ARDS) through the mesenteric lymph drainage

Efficacy and safety of a third anti-TNF monoclonal antibody in Crohn's disease after failure of two other anti-TNF.

Adalimumab (ADA) and certolizumab pegol (CZP) have demonstrated efficacy in Crohn's disease (CD) patients previously treated with infliximab (IFX). Aim: To assess the efficacy and tolerability of a third anti-TNF in CD after failure of and/or intolerance to two different anti-TNF. Methods: CD patients who received ADA or CZP after loss of response and/or intolerance to two anti-TNF were included in this retrospective study. Data were collected using a standardized questionnaire. Clinical response, duration, safety and reasons for discontinuation were assessed. Results: Sixty-seven patients treated with CZP (n=40) or ADA (n=27) were included. A clinical response was observed in 41 (61%) at week 6 and 34 patients (51%) at week 20. The probability of remaining under treatment at 3 months, 6 months and 9 months was 68%, 60% and 45%, respectively. At the end of follow-up, the third anti-TNF had been stopped in 36 patients for intolerance (n=13), or failure (n=23). Two deaths were observed. Conclusion: Treatment, with a third anti-TNF (CZP or ADA) agent, of CD patients who have experienced loss of response and/or intolerance to two anti-TNF antibodies, has favorable short- and long-term efficacy and is an option to be considered in patients with no other therapeutic options

Topological Modelling of Deep Ulcerations in Patients with Ulcerative Colitis

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L’appendicectomie est un facteur de risque de dysplasie de haut grade et de cancer colorectal dans la rectocolite hémorragique

National audienceIntroduction L’appendicectomie est considérée comme facteur protecteur de la rectocolite hémorragique (RCH). Le but de ce travail était de tester l’appendicectomie pour appendicite (APA) et sans appendicite (ASA) sur un modèle murin de RCH (modèle IL10/ Nox1DKO) et de confirmer nos observations chez l’homme Matériels et méthodes Trois groupes de souris mâles (20/groupe) ont été opérés (groupes APA, ASA et contrôle), euthanasiés à un mois, et leurs colons ont été analysés en aveugle. La sévérité de la colite et la présence de dysplasie de haut grade (DHG) et de cancer colorectal (CCR) ont été évaluées. Une cohorte bicentrique de patients RCH opérés consécutivement de colectomie a été étudiée en s’intéressant à l’antécédent d’appendicectomie Résultats Dans le modèle murin, seule l’APA était associée à une amélioration de la colite (p = 0,0005), avec un effet plus important chez les souris jeunes. L’ASA était associée à un taux élevé inattendu de DHG/CCR (65 % versus 0 % dans les autres groupes, p < 0,0001). Parmi les 232 patients RCH de la cohorte, 15 présentaient une appendicectomie, dont 5 avaient un CCR (33 %) et 4 une DHG (27 %) versus 12 (5,5 %) et 18 (8,3 %) chez les non-appendicectomisés, En analyse multivariée, l’appendicectomie était associée à la DHG/CCR dans la RCH (OR = 16.88, 9 5 % CI [3.3-112.7]). Conclusion Le rôle protecteur de l’appendice dans la RCH est lié à l’appendicite mais l’appendicectomie est associée à une néoplasie colique dans la RCH chez l’homme et la souris. Déclaration d’intérêt Les auteurs n’ont pas transmis de conflits d’intérêt

Detection of ulcerative colitis lesions from weakly annotated colonoscopy videos using bounding boxes

International audienceUlcerative colitis is a chronic disease characterized by bleeding and ulcers in the colon. Currently, the gastroenterologist reviews the colonoscopy video to assess the disease severity using an endoscopic score. This task is time-consuming and does not consider the size and the number of lesions. Consequently, automatic detection methods were proposed enabling fine-grained assessment of lesion severity. However, they depend on the quality of the training set, and its specificity to the application context. To suit the local clinical setup, we opted for an internal training dataset containing only rough bounding box annotations around lesions. Color information is the primary indicator used by specialists to recognize the lesions. Thus, we propose to use linear models in suitable color spaces to detect lesions. We introduce an efficient sampling scheme for exploring the set of linear classifiers and removing trivial models i.e. those showing zero false negative or positive ratio. Using bounding boxes leads to ex- aggerated false negative/positive ratios due to mislabeled pixels, especially in the corners, resulting in decreased models’ accuracy. Therefore, we propose to evaluate the model sensitivity on the annotation level instead of the pixel level. Our sampling strategy can eliminate up to 25% of trivial models. Despite the limited annotations’ quality, the detectors achieved good performance (93% specificity/89% sensitivity for bleeding and 57% specificity/83% sensitivity for ulcers). The best models exhibit low variability when tested on a small subset of endoscopic images. However, the inter-patient model performance was variable suggesting that appearance normalization is critical in this context.</p

AUTOMATIC BLEEDING AND ULCER DETECTION FROM LIMITED QUALITY ANNOTATIONS IN ULCERATIVE COLITIS

International audienceAbstract Ulcerative colitis is an idiopathic inflammatory disorder affecting the mucosa of the colon with superficial erosions and ulcers associated with bleeding. Severity assessment using current scoring schemes such as UCEIS and MAYO relies on the subjective interpretation of the physician and fails to take into account the size of the different lesions, their number and their distribution throughout the colon. Automatic lesion detection and grading procedures can enable fine-grained assessment of lesion severity for treatment follow-up. This work aims to learn automatic bleeding and ulcer lesion detectors. As such algorithms may need to be tuned to the characteristics of the equipment used to perform the colonoscopy, we train our detectors on a dataset obtained by the Gastroenterology group at the Bichat and Beaujon hospitals. The patients’ videos were anonymous, analyzed after obtaining their consent. The study was approved by the local research study committee. To minimize expert annotation burden, only rectangular annotations are required instead of a precise delineation of lesion boundaries (Figure 1). However, this dataset contains many mislabeled pixels, especially in the corners of the rectangles. This affects the evaluation of the models’ performance and our ability to find correct models. Standard sensitivity and specificity cannot be used effectively on this dataset. We propose to evaluate model sensitivity on the annotation level and keep specificity at the pixel level. On the training set, we consider that a model correctly identifies a lesion if it agrees with the expert on a subset of the annotation, and count the detected annotations weighted by their area. For robustness and ease of interpretation, we explore the set of linear classifiers, and propose an efficient sampling scheme that rejects trivial models. This method is evaluated on a database of 10 colonoscopy videos (5 training videos and 5 test videos). In spite of the limited quality of the annotations, we find lesion detectors with a good annotation-level sensitivity (93% specificity / 89% sensitivity for bleeding and 57% specificity / 83% sensitivity for ulcers) and visual performance (see Figure 1). The detector performance is computed reliably. We evaluated sensitivity and specificity on 20 random subsets containing 10% of the images, and obtain similar performance for the same patient for all models (cf Figure 2). Figure 1. From left to right: Annotated frame and corresponding bleeding and ulcer detection with the best linear models Figure 2. Performance of the three best linear models on random subsets extracted from 5 training videos (left) and 5 test videos (right). Each ellipse corresponds to one linear model applied to a given video. Its size represents the variability (standard deviation) of sensitivity and specificity among the random subsets. However, we observe that the inter-patient performance is variable and that the best models can fail on some patients. In Figure 2, the sensitivity is below 20% is some cases. This suggests that the models are not universal because bleeding and ulcers have a different appearance in patients, and that this should be corrected before automatic detection. Alternatively, models should be adapted to the patient characteristics