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Background: Intestinal ultrasound (IUS) is a noninvasive tool to assess bowel inflammation. There is a paucity of data on its accuracy in pediatric patients., Aim: The aim of this study is to evaluate the diagnostic performance of bowel wall thickness (BWT) measured using IUS compared with endoscopic disease activity in children suspected of having inflammatory bowel disease (IBD)., Methods: We conducted a single-center cross-sectional pilot study of pediatric patients suspected to have previously undiagnosed IBD. Endoscopic inflammation was graded using segmental scores of the Simple Endoscopic Score for Crohn's Disease (SES-CD) and the Ulcerative Colitis Endoscopic Index of Severity (UCEIS) and classified as having healthy, mild, or moderate/severe disease activity. Association between BWT and endoscopic severity was assessed using the Kruskal-Wallis test. The diagnostic performance of BWT to detect active disease at endoscopy was evaluated using the area under the receiver operating characteristic curve; sensitivity and specificity were calculated., Results: In all, 174 bowel segments in 33 children were assessed by IUS and ileocolonoscopy. An elevated median BWT was associated with increased bowel segment disease severity, classified by the SES-CD (P < .001) and the UCEIS (P < .01). Using a cutoff value of 1.9 mm, we found that the BWT had an area under the receiver operating characteristic curve of 0.743 (95% CI, 0.67-0.82), a sensitivity of 64% (95% CI, 53%-73%), and a specificity of 76% (95% CI, 65%-85%) to detect inflamed bowel., Conclusion: Increasing BWT is associated with increasing endoscopic activity in pediatric IBD. Our study suggests that the optimal BWT cutoff value for detecting active disease may be less than that seen in adults. Additional pediatric studies are needed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Crohn’s & Colitis Foundation. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Dysbiosis corresponds to the disruption of a formerly stable, functionally complete microbiota. In the gut, this imbalance can lead to adverse health outcomes in both the short and long terms, with a potential increase in the lifetime risks of various noncommunicable diseases and disorders such as atopy (like asthma), inflammatory bowel disease, neurological disorders, and even behavioural and psychological disorders. Although antibiotics are highly effective in reducing morbidity and mortality in infectious diseases, antibiotic-associated diarrhoea is a common, non-negligible clinical sign of gut dysbiosis (and the only visible one). Re-establishment of a normal (functional) gut microbiota is promoted by completion of the clinically indicated course of antibiotics, the removal of any other perturbing external factors, the passage of time (i.e. recovery through the microbiota's natural resilience), appropriate nutritional support, and-in selected cases-the addition of probiotics. Systematic reviews and meta-analyses of clinical trials have confirmed the strain-specific efficacy of some probiotics (notably the yeast Saccharomyces boulardii CNCM I-745 and the bacterium Lactobacillus rhamnosus GG) in the treatment and/or prevention of antibiotic-associated diarrhoea in children and in adults. Unusually for a probiotic, S. boulardii is a eukaryote and is not therefore directly affected by antibiotics-making it suitable for administration in cases of antibiotic-associated diarrhoea. A robust body of evidence from clinical trials and meta-analyses shows that the timely administration of an adequately dosed probiotic (upon initiation of antibiotic treatment or within 48 h) can help to prevent or resolve the consequences of antibiotic-associated dysbiosis (such as diarrhoea) and promote the resilience of the gut microbiota and a return to the pre-antibiotic state. A focus on the prescription of evidence-based, adequately dosed probiotics should help to limit unjustified and potentially ineffective self-medication., (© 2024. The Author(s).)

Background & Aims: Withdrawal of immunomodulators (IMMs) or tumor necrosis factor (TNF) antagonists in patients with inflammatory bowel diseases (IBDs) in remission on combination therapy is attractive. We evaluated the efficacy and safety of (1) IMM, or (2) TNF antagonist withdrawal in patients with IBD in sustained remission on combination therapy., Methods: Through a systematic review till March 31, 2023, we identified randomized controlled trials (RCTs) that compared the efficacy and safety of IMM or TNF antagonist withdrawal vs continued combination therapy, in patients with IBD in sustained corticosteroid-free clinical remission for >6 months on combination therapy. Primary outcome was risk of relapse and serious adverse events at 12 months. We conducted meta-analysis to calculate relative risk (RR) and 95% confidence interval (CI) and used Grading of Recommendations Assessment, Development and Evaluation (GRADE) to appraise certainty of evidence., Results: We identified 8 RCTs with 733 patients (77% with Crohn's disease, 91% on infliximab-based combination therapy). On meta-analysis of 5 RCTs, there was no difference in the risk of relapse between patients with IMM withdrawal (continued TNF antagonist monotherapy) vs continued combination therapy (16.8% vs 14.9%; RR, 1.15; 95% CI, 0.75-1.76) without heterogeneity (low certainty of evidence). TNF antagonist withdrawal (continued IMM monotherapy) was associated with 2.4-times higher risk of relapse compared with continuing combination therapy (31.5% vs 11.2%; RR, 2.35; 95% CI, 1.38-4.01), with minimal heterogeneity (low certainty of evidence). There was no difference in the risk of serious adverse events with IMM or TNF antagonist withdrawal vs continued combination therapy., Conclusions: In patients with IBD in sustained corticosteroid-free clinical remission for >6 months on combination therapy, de-escalation with TNF antagonist withdrawal, but not IMM withdrawal, was associated with an increased risk of relapse., (Copyright © 2024 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Chronic colonic injury and inflammation pose high risks for field cancerization, wherein injury-associated mutations promote stem cell fitness and gradual clonal expansion. However, the long-term stability of some colitis-associated mutational fields could suggest alternate origins. Here, studies of acute murine colitis reveal a punctuated mechanism of massive, neutral clonal expansion during normal wound healing. Through three-dimensional (3D) imaging, quantitative fate mapping, and single-cell transcriptomics, we show that epithelial wound repair begins with the loss of structural constraints on regeneration, forming fused labyrinthine channels containing epithelial cells reprogrammed to a non-proliferative plastic state. A small but highly proliferative set of epithelial founder progenitor cells (FPCs) subsequently emerges and undergoes extensive cell division, enabling fluid-like lineage mixing and spreading across the colonic surface. Crypt budding restores the glandular organization, imprinting the pattern of clonal expansion. The emergence and functions of FPCs within a critical window of plasticity represent regenerative targets with implications for preneoplasia., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Colonic epithelial repair is a key determinant of health. Repair involves changes in epithelial differentiation, an extensive proliferative response, and upregulation of regeneration-associated "fetal-like" transcripts, including Ly6a (Sca-1), that represent Yap1 and interferon targets. However, little is known about how this regenerative program terminates and how homeostasis is restored during injury and inflammation. Here we show that, after the initial entry into the regenerative state, the subsequent upregulation of tumor necrosis factor (TNF) receptor 2 (R2, TNFR2, Tnfrsf1b ) clears the regenerative signaling and restores homeostatic patterns of epithelial differentiation. Targeted deletion of epithelial TNFR2 in vivo and in colonoid cultures revealed persistent expression of Ly6a , hyperproliferation, and reduced secretory differentiation. Moreover, mice lacking epithelial TNFR2 also failed to complete colon ulcer healing, suggesting that partial resolution of regenerative signaling is essential for the completion of the repair process. These results demonstrate how epithelial cells dynamically leverage a colitis-associated cytokine to choreograph repair., Competing Interests: Authors declare no competing interests., (© 2023 The Authors.)

Background & Aims: Epithelial wound healing is compromised and represents an unleveraged therapeutic target in inflammatory bowel disease (IBD). Intestinal epithelial cells exhibit plasticity that facilitates dedifferentiation and repair during the response to injury. However, it is not known whether epithelial cells of a neighboring organ can be activated to mediate re-epithelialization in acute colitis. Histological findings of a permanent squamous tissue structure in the distal colon in human IBD could suggest diverse cellular origins of repair-associated epithelium. Here, we tested whether skin-like cells from the anus mediate colonic re-epithelialization in murine colitis., Methods: We studied dextran sulfate sodium-induced colitis and interleukin 10-deficient colitis in transgenic mice. We performed lineage tracing, 3-dimensional (3D) imaging, single-cell transcriptomics, and biophysical modeling to map squamous cell fates and to identify squamous cell types involved in colonic repair., Results: In acute and chronic colitis, we found a large squamous epithelium, called squamous neo-epithelium of the colon (SNEC), near the anorectal junction. Neighboring squamous cells of the anus rapidly migrate into the ulcerated colon and establish this permanent epithelium of crypt-like morphology. These squamous cells derive from a small unique transition zone, distal to the border of colonic and anal epithelium, that resists colitic injury. The cells of this zone have a pre-loaded program of colonic differentiation and further upregulate key aspects of colonic epithelium during repair., Conclusion: Transitional anal cells represent unique reserve cells capable of rebuilding epithelial structures in the colon after colitis. Further study of these cells could reveal novel approaches to direct mucosal healing in inflammation and disease., (Copyright © 2022 AGA Institute. Published by Elsevier Inc. All rights reserved.)