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Recent evidence indicates that the gut microbiota (GM) has a significant impact on the inflammatory bowel disease (IBD) progression. Our aim was to investigate the GM profiles, the Microbial Dysbiosis Index (MDI) and the intestinal microbiota-associated markers in relation to IBD clinical characteristics and disease state. We performed 16S rRNA metataxonomy on both stools and ileal biopsies, metabolic dysbiosis tests on urine and intestinal permeability and mucosal immunity activation tests on the stools of 35 IBD paediatric patients. On the GM profile, we assigned the MDI to each patient. In the statistical analyses, the MDI was correlated with clinical parameters and intestinal microbial-associated markers. In IBD patients with high MDI, Gemellaceae and Enterobacteriaceae were increased in stools, and Fusobacterium , Haemophilus and Veillonella were increased in ileal biopsies. Ruminococcaceae and WAL_1855D were enriched in active disease condition; the last one was also positively correlated to MDI. Furthermore, the MDI results correlated with PUCAI and Matts scores in ulcerative colitis patients (UC). Finally, in our patients, we detected metabolic dysbiosis, intestinal permeability and mucosal immunity activation. In conclusion, the MDI showed a strong association with both severity and activity of IBD and a positive correlation with clinical scores, especially in UC. Thus, this evidence could be a useful tool for the diagnosis and prognosis of IBD.

Extracellular High-mobility group box 1 (HMGB1) contributes to the pathogenesis of inflammatory disorders, including inflammatory bowel diseases (IBD). Poly (ADP-ribose) polymerase 1 (PARP1) has been recently reported to promote HMGB1 acetylation and its secretion outside cells. In this study, the relationship between HMGB1 and PARP1 in controlling intestinal inflammation was explored. C57BL6/J wild type (WT) and PARP1 -/- mice were treated with DSS to induce acute colitis, or with the DSS and PARP1 inhibitor, PJ34. Human intestinal organoids, which are originated from ulcerative colitis (UC) patients, were exposed to pro-inflammatory cytokines (INFγ + TNFα) to induce intestinal inflammation, or coexposed to cytokines and PJ34. Results show that PARP1 -/- mice develop less severe colitis than WT mice, evidenced by a significant decrease in fecal and serum HMGB1, and, similarly, treating WT mice with PJ34 reduces the secreted HMGB1. The exposure of intestinal organoids to pro-inflammatory cytokines results in PARP1 activation and HMGB1 secretion; nevertheless, the co-exposure to PJ34, significantly reduces the release of HMGB1, improving inflammation and oxidative stress. Finally, HMGB1 release during inflammation is associated with its PARP1-induced PARylation in RAW264.7 cells. These findings offer novel evidence that PARP1 favors HMGB1 secretion in intestinal inflammation and suggest that impairing PARP1 might be a novel approach to manage IBD.

Background: Faecal biomarkers have emerged as important tools in managing of inflammatory bowel disease [IBD], which includes Crohn's disease [CD] and ulcerative colitis [UC]., Aim: To identify new biomarkers of gut inflammation in the stools of IBD patients using a proteomic approach., Methods: Proteomic analysis of stools was performed in patients with both active CD and CD in remission and in controls by 2-DIGE and MALDI-TOF/TOF MS. An ELISA was used to confirm results in a second cohort of IBD patients and controls., Results: 2-DIGE analysis detected 70 spots in the stools of patients with active CD or patients in remission CD and in controls. MALDI-TOF/TOF MS analysis identified 21 proteins with Chymotrypsin C, Gelsolin and Rho GDP-dissociation inhibitor 2 [RhoGDI2] best correlating with the levels of intestinal inflammation. Results were confirmed in a second cohort of IBD patients and controls [57 CD, 60 UC, 31 controls]. The identified faecal markers significantly correlated with the severity of intestinal inflammation in IBD patients [SES-CD in CD, Mayo endoscopic subscore in UC] [CD; Chymotrypsin-C: r = 0.64, p < 0.001; Gelsolin: r = 0.82, p < 0.001; RhoGDI2: r = 0.64, p < 0.001; UC; Chymotrypsin-C: r = 0.76, p < 0.001; Gelsolin: r = 0.75, p < 0.001; RhoGDI2: r = 0.63, p < 0.001]. Moreover, ROC analysis showed that Gelsolin [p < 0.0002] and RhoGDI2 [p < 0.0001] in CD, and RhoGDI2 [p = 0.0004] in UC, have higher sensitivity and specificity than faecal calprotectin in discriminating between patients and controls., Conclusions: We show for the first time that 2-DIGE is a reliable method to detect proteins in human stools. Three novel faecal biomarkers of gut inflammation have been identified that display good specificity and sensitivity for identifying IBD and significantly correlate with IBD severity., (© The Author(s) 2022. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: An altered gut microbiota profile has been widely documented in inflammatory bowel diseases (IBD). The intestinal microbial community has been more frequently investigated in the stools than at the level of the mucosa, while most of the studies have been performed in adults. We aimed to define the gut microbiota profile either by assessing fecal and colonic mucosa samples (inflamed or not) from pediatric IBD patients., Patients and Methods: Fecal and colonic samples from pediatric IBD (Crohn's disease or ulcerative colitis) and controls were analyzed. The relative abundance of bacteria at phylum and genus/species levels and bacterial diversity were determined through 16S rRNA sequence-based of fecal and mucosal microbiota analysis., Results: A total of 59 children with IBD (26 Crohn's disease, 33 ulcerative colitis) and 39 controls were analyzed. A clear separation between IBD and controls in the overall composition of fecal and mucosal microbiota was found, as well as a reduced bacterial richness in the fecal microbiota of IBD. At the phylum level, abundance of Proteobacteria and Actinobacteria occurred in fecal microbiota of IBD, while species with anti-inflammatory properties (i.e., Ruminococcus) were reduced. Fusobacterium prevailed in inflamed IBD areas in comparison to noninflamed and controls samples., Conclusion: Significant alterations in gut microbiota profile were shown in our IBD pediatric patients, in whom an abundance of species with a proinflammatory mucosal activity was clearly detected. An analysis of gut microbiota could be incorporated in designing personalized IBD treatment scenarios in future., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

In the last decade, the widespread application of shotgun metagenomics provided extensive characterization of the bacterial "dark matter" of the gut microbiome, propelling the development of dedicated, standardized bioinformatic pipelines and the systematic collection of metagenomic data into comprehensive databases. The advent of next-generation sequencing also unravels a previously underestimated viral population (virome) present in the human gut. Despite extensive efforts to characterize the human gut virome, to date, little is known about the childhood gut virome. However, alterations of the gut virome in children have been linked to pathological conditions such as inflammatory bowel disease, type 1 diabetes, malnutrition, diarrhea and celiac disease.

Background: Endoplasmic reticulum stress and unfolded protein response have been recently associated with the development of inflammatory bowel diseases in adults. We aimed at assessing the involvement of these pathways also in paediatric inflammatory bowel disease by analysing the expression of the main genes involved in endoplasmic reticulum stress and correlating them with the degree of intestinal inflammation., Methods: Real-time PCR and Western blot analysis of the expression of the endoplasmic reticulum stress marker HSPA5 and of selected genes representing the three pathways of unfolded protein response (IRE-XBP1, PERK-ATF4, ATF6p90-p50) in inflamed and uninflamed biopsies from 28 inflammatory bowel disease paediatric patients and 10 controls., Results: HSPA5, PDIA4, as well as unspliced and spliced XBP1 mRNAs were significantly increased in patients' inflamed colonic mucosa compared to uninflamed mucosa and controls. HSPA5, PDIA4, ATF6, and phospho-IRE proteins were also upregulated, indicating the activation of the IRE-XBP1 and ATF6p90-p50 branches of unfolded protein response. A positive significant correlation between interleukin-8 levels, as a marker of inflammation, and upregulated genes was found in the inflamed colonic mucosa., Conclusion: A deregulation of the genes involved in the endoplasmic reticulum stress and unfolded protein response pathways may be a key component of the inflammatory response in paediatric patients with inflammatory bowel disease., (Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.)

IBD includes two classic entities, Crohn's disease and ulcerative colitis, and a third undetermined form (IBD-U), characterized by a chronic relapsing course resulting in a high rate of morbidity and impaired quality of life. Children with IBD are vulnerable in terms of growth failure, malnutrition and emotional effects. The aims of therapy have now transitioned from symptomatic control to the achievement of mucosal healing and deep remission. This type of therapy has been made possible by the advent of disease-modifying drugs, such as biologic agents, which are capable of interrupting the inflammatory cascade underlying IBD. Biologic agents are generally administered in patients who are refractory to conventional therapies. However, there is growing support that such agents could be used in the initial phases of the disease, typically in paediatric patients, to interrupt and cease the inflammatory process. Until several years ago, most therapeutic programmes in paediatric patients with IBD were borrowed from adult trials, whereas paediatric studies were often retrospective and uncontrolled. However, guidelines on therapeutic management of paediatric IBD and controlled, prospective, randomized trials including children with IBD have now been published. Here, the current knowledge concerning treatment options for children with IBD are reported. We also highlight the effectiveness and safety of new therapeutic advances in these paediatric patients.

Objectives: A new caspase-independent mode of programmed cell death, termed necroptosis, has recently been identified. Altered expression of molecules involved in the necroptosis pathway has been shown to trigger intestinal inflammation. The initiation of necroptosis is principally mediated by the release of receptor interacting protein 3 (RIP3) from suppression by caspase-8. Furthermore, it has been suggested that the mixed lineage kinase domain-like (MLKL) factor is an interacting target of RIP3 in active necroptosis. This study aims at investigating the occurrence of necroptosis in children with inflammatory bowel disease (IBD) and its contribution to human intestinal inflammation., Methods: Biopsy samples were collected from the ileum and colon of 33 children with Crohn's disease, 30 with ulcerative colitis, and 20 healthy controls. Ten children with allergic colitis (AC) were used as non-IBD comparators. RIP3, caspase-8, and MLKL protein expression levels were evaluated by western blotting. The adenocarcinoma cell line HT29 was used for in vitro experiments., Results: RIP3 and MLKL increased (P<0.01) in inflamed tissues of IBD and AC patients, whereas caspase-8 was reduced. No variations were observed in uninflamed tissues of patients. The relationship between RIP3 increase, active necroptosis, and intestinal inflammation was confirmed by in vitro analyses., Conclusions: We show for the first time that necroptosis is strongly associated with intestinal inflammation in children with IBD and contributes to strengthen the inflammatory process. We believe that RIP3 and MLKL could represent attractive targets for the management of human IBD.

Inflammatory bowel disease (IBD) is the result of an altered immune homeostasis within the intestinal mucosa against the gut microbiota, leading to chronic inflammation in genetically predisposed individuals. Under normal conditions, the immune system defends against pathogens and prevents the passage of excessive intestinal bacteria; regulatory pathways must maintain a low-grade, controlled inflammation in a healthy gut, but also induce a protective response against pathogens. The innate immune system is the first-line defense from microbes; dendritic cells, macrophages, and epithelial cells produce an initial, immediate response. The immune system constantly controls commensal bacteria and utilizes constitutive antimicrobial mechanisms to sustain immune homeostasis. The discovery that several genes linked to IBD modulate microbial recognition and innate immune pathways, such as nucleotide oligomerization domain 2 (Nod2), and genes that mediate autophagy (ie, ATG16L1, IRGM), has highlighted the critical role of host-microbe interactions in controlling intestinal immune homeostasis. Commensal microorganisms actively interact with the intestinal mucosa and influence the activity of the immune system as well as the amplitude of the immune response. In contrast, host factors can influence microbes, which in turn modulate disease susceptibility. In this paper, we focus on the mechanisms that mediate host-microbe interactions and how the disruption of this balance leads to chronic intestinal inflammation in IBD.

Background: Small bowel endoscopy is critical in revealing an inflammatory bowel disease (IBD) previously undetected and in classifying the IBD patients, i.e. Crohn's disease or ulcerative colitis., Methods: A prospective paediatric study on the usefulness of wireless capsule endoscopy (WCE) was performed in 117 children (age range: 4-17 years) with established or suspected IBD and compared with non endoscopic imaging tools. All patients underwent upper and lower gastrointestinal endoscopy., Results: In Crohn's disease patients (CD, n=44), small bowel lesions were revealed by imaging tools in 8 and by WCE in 18 patients, respectively (p<0.01). No small bowel involvement was observed in 29 ulcerative colitis patients by both imaging tools and WCE. Of 26 unclassified IBD, small bowel lesions typical of Crohn's disease were detected by imaging in 7 and by WCE in 16 (p<0.05). Of 18 patients with suspected IBD, small bowel lesions typical of Crohn's disease were observed in 9 with WCE, vs. only in 4 with imaging (p<0.01). No cases of capsule retention occurred., Conclusions: WCE is valuable in revealing small bowel lesions in children with a previous diagnosis of CD and unexplained clinical and laboratory data. It is also helpful in unclassified IBD patients. This tool can influence the management and the course of IBD., (Copyright © 2010 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.)

Inflammatory bowel diseases (IBDs) are lifelong inflammatory gastrointestinal diseases starting in about one third of patients during childhood. Treatment strategies aim to control this chronic inflammatory process. Owing to recent advances in the understanding of IBD, immunosuppressive agents (mainly against TNFalpha directed) as well as biological drugs are more and more often used. This therapeutic approach clearly improved the clinical condition of the majority of patients with IBD. However, with this more aggressive treatment strategy, safety concerns clearly arise. Recently, the description of a series of a particularly severe form of T cell lymphoma in pediatric and young adult patients with IBD under immunomodulator and biological combination therapy raised the question of the risks of treatment-induced side effects or complications. As reviewed in the present article, there is a slightly increased risk of not only lymphoma development in IBD patients, potentially related to the inflammatory process, but also to the use of immunosuppressive therapies. On the basis of the literature data, were analyzed current treatment strategies for children with moderate-to-severe IBD, who are candidates to receive immunomodulator and/or biological agents potentially accelerating the risk of lymphoma development. Comparative clinical studies in IBD are still missing; however, it is prudent to think about adapting immunosuppressive therapies to the inflammatory process of the underlying disorder and if possible to reduce them to monotherapy. Alternative treatment strategies for heavy immunosuppression exist (eg, enteral nutrition in Crohn disease or colectomy in patients with ulcerative colitis) and should be considered whenever appropriate. There is a major need for comparative studies before evidence-based guidelines can be established for safest and best treatment strategies of pediatric patients with IBD.

Summary Background Intestinal microbiota manipulation, one of the pathogenetic components of inflammatory bowel disease (IBD), has become an attractive therapy for ulcerative colitis (UC). Aim To assess in children with active distal UC the effectiveness of Lactobacillus (L) reuteri ATCC 55730 enema on inflammation and cytokine expression of rectal mucosa. Methods A total of 40 patients (median age: 7.2 years range 6-18) with mild to moderate UC were enrolled in a prospective, randomised, placebo-controlled study. They received an enema solution containing 1010 CFU of L. reuteri ATCC 55730 or placebo for 8 weeks, in addition to oral mesalazine. Clinical endoscopic and histological scores as well as rectal mucosal expression levels of IL-10, IL-1β, TNFα and IL-8 were evaluated at the beginning and at the end of the trial. Results Thirty-one patients accomplished the trial (17 males, median age 13 year, range 7-18). Mayo score (including clinical and endoscopic features) decreased significantly in the L. reuteri group (3.2 ± 1.3 vs. 8.6 ± 0.8, P < 0.01) compared with placebo (7.1 ± 1.1 vs. 8.7 ± 0.7, NS); furthermore, histological score significantly decrease only in the L. reuteri group (0.6 ± 0.5 vs. 4.5 ± 0.6, P < 0.01) (placebo: 2.9 ± 0.8 vs. 4.6 ± 0.6, NS). At the post-trial evaluation of cytokine mucosal expression levels, IL-10 significantly increased ( P < 0.01) whereas IL-1β, TNFα and IL-8 significantly decreased ( P < 0.01) only in the L. reuteri group. Conclusions In children with active distal ulcerative colitis, rectal infusion of L. reuteri is effective in improving mucosal inflammation and changing mucosal expression levels of some cytokines involved in the mechanisms of inflammatory bowel disease. [ABSTRACT FROM AUTHOR]