Inflammatory bowel diseases and food additives:to add fuel on the flames!

International audienc

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Mineralcorticoid receptor : a potential target in intestinal fibrosis

Les maladies inflammatoires chroniques de l’intestin (MICI) se développent chez des individus génétiquement prédisposés sous l’influence de facteurs environnementaux. La fibrose intestinale est une complication fréquente de ces MICI sans traitement spécifique, qui se caractérise par une accumulation de matrice extracellulaire synthétisée par les cellules mésenchymateuses. Le récepteur minéralocorticoïde (RM) est l’effecteur terminal du système hormonal rénineangiotensine-aldostérone (SRAA). Le RM et l’ensemble des composants du SRAA sont exprimés dans le tractus gastro-intestinal et leur expression est augmentée dans l’intestin des patients atteints de MICI. L’antagonisme du RM exerce des effets bénéfiques sur la réduction de l’inflammation et de la fibrose extra-intestinales.L’objectif principal de ce travail de thèse était de déterminer si l’antagonisme du RM exerce des effets bénéfiques sur la fibrogenèse intestinale et d’en identifier les mécanismes sous-jacents. Un modèle de colite chronique induite chez la Souris et des modèles cellulaires de fibrose intestinale ont été utilisés. L’antagonisme du RM a été étudiée par des approches pharmacologiques et par invalidation génétique. Nous avons montré que l’inhibition pharmacologique ou génétique du RM diminue l’inflammation et la fibrose intestinales dans le modèle de colite chronique chez la Souris. L’activation du RM par l’aldostérone augmente la prolifération ainsi que l’expression de TGF-β1 des fibroblastes coliques humains et promeut la transition endothélio-mésanchymateuse, des cellules endothéliales vasculaires intestinales humaines. Nous avons également montré que la lipocaline associée à la gélatinase des neutrophiles (NGAL) est une cible du RM au niveau de l’intestin et est responsable des effets pro-fibrotiques médiés par l’activation du RM. L’invalidation génétique de la NGAL inhibe la voie de signalisation du TGF-β1 dépendante des SMAD, qui joue un rôle central dans l’initiation et le développement de la fibrose. En conclusion, nous avons d’une part démontré l’implication du RM dans la fibrose intestinale et d’autre part montré que ses effets étaient dépendants de la NGAL. Ainsi, l’antagonisme du RM pourrait constituer une nouvelle cible thérapeutique dans la fibrose intestinale associée aux MICI et permettrait de repositionner des molécules déjà disponibles dans le contexte des MICI.Inflammatory bowel diseases (IBD) occur in people with a genetic predisposition under the influence of environmental factors. Intestinal fibrosis is a common complication in IBD with no specific therapy which is characterized by an accumulative deposit of extra-cellular matrix produced by mesenchymal cells. Mineralocorticoid receptor (MR) is the final effector of renin-angiotensin-aldosterone system (RAAS). MR and all components of RAAS are expressed in the gastrointestinal tract and are up-regulated in the intestine from IBD patients. MR antagonism exerts beneficial properties in inflammation and fibrosis from extra-intestinal organs. We aimed to investigate whether MR antagonism had beneficial effects in intestinal fibrogenesis using murine chronic colitis and cellular models of intestinal fibrosis. MR antagonism was investigated by a dual approach using pharmacological inhibition and genetic invalidation. In the present study, we have demonstrated that pharmacological or genetic MR antagonism reduced inflammation and intestinal fibrosis in murine DSS chronic chemically-induced colitis. MR activation by aldosterone increased cell proliferation and TGF-β1 production in human colonic fibroblasts and human intestinal endothelial cells. Lipocalin associated with neutrophil gelatinase (NGAL) mediated pro-fibrotic effects via the activation of RM by aldosterone. Genetic invalidation of NGAL also reduced the SMAD-dependent TGF-β1 signaling pathway. In conclusion, we have demonstrated the MR involvement in intestinal fibrosis and these effects are mediated through NGAL. Thus, MR antagonism may represent a novel attractive approach in the treatment of intestinal fibrosis associated with IBD and may allow the repositioning molecules already available in the field of IBD

Diet–Microbiota Interplay: An Emerging Player in Macrophage Plasticity and Intestinal Health

Inflammatory bowel diseases (IBD) are chronic disorders of the gastrointestinal tract with an increasing prevalence worldwide. Targeted therapies for IBD are limited by several factors, including the therapeutic ceiling and the high incidence of non-responders or loss-of-response. In order to improve therapeutic efficacy, there is critical need to decipher disease pathogenesis, currently not well understood. Macrophages, innate immune cells that exhibit high plasticity, perpetuate inflammatory signalling in IBD through excessive release of inflammatory mediators. In recent years, pioneering research has revealed the importance of the interplay between macrophages and gut microbiota in maintaining intestinal homeostasis. Particular attention is focusing on microbiota-derived metabolites, believed to possess immunomodulatory properties capable of manipulating macrophage plasticity. Microbiota-derived short-chain fatty acids (SCFAs) and indole compounds, along with dietary sourced omega-3 (ω-3) polyunsaturated fatty acids (PUFA), exert anti-inflammatory effects, attributable to interactions with macrophages. Before we can effectively incorporate these metabolites into IBD therapies, a deeper understanding of microbiota–macrophage interactions at a molecular level is necessary. Therefore, the aim of this review is firstly to detail current knowledge regarding how diet and microbiota-derived metabolites modify macrophage plasticity. Later, we discuss the concept of therapeutic strategies directed at microbiota–macrophage interactions, which could be highly valuable for IBD therapies in the future

Diet–Microbiota Interplay: An Emerging Player in Macrophage Plasticity and Intestinal Health

Inflammatory bowel diseases (IBD) are chronic disorders of the gastrointestinal tract with an increasing prevalence worldwide. Targeted therapies for IBD are limited by several factors, including the therapeutic ceiling and the high incidence of non-responders or loss-of-response. In order to improve therapeutic efficacy, there is critical need to decipher disease pathogenesis, currently not well understood. Macrophages, innate immune cells that exhibit high plasticity, perpetuate inflammatory signalling in IBD through excessive release of inflammatory mediators. In recent years, pioneering research has revealed the importance of the interplay between macrophages and gut microbiota in maintaining intestinal homeostasis. Particular attention is focusing on microbiota-derived metabolites, believed to possess immunomodulatory properties capable of manipulating macrophage plasticity. Microbiota-derived short-chain fatty acids (SCFAs) and indole compounds, along with dietary sourced omega-3 (ω-3) polyunsaturated fatty acids (PUFA), exert anti-inflammatory effects, attributable to interactions with macrophages. Before we can effectively incorporate these metabolites into IBD therapies, a deeper understanding of microbiota–macrophage interactions at a molecular level is necessary. Therefore, the aim of this review is firstly to detail current knowledge regarding how diet and microbiota-derived metabolites modify macrophage plasticity. Later, we discuss the concept of therapeutic strategies directed at microbiota–macrophage interactions, which could be highly valuable for IBD therapies in the future

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

International audienceIntestinal 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

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

Diet in Intestinal Fibrosis: A Double-Edged Sword

International audienceThe 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 AhR Ligands Have No Anti-Fibrotic Properties in TGF-β1-Stimulated Human Colonic Fibroblasts

International audienceBackground: 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

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

International audienceAbstract 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