Prevalence of inflammatory bowel disease has been on the rise in recent years, especially in pediatric populations. This study aimed to provide precise identification and stratification of pediatric patients with diagnosed ulcerative colitis (UC) according to the severity of their condition and the prediction for standard treatment according to the specific expression of candidate miRNAs. We enrolled consecutive, therapeutically naïve, pediatric UC patients with confirmed pancolitis. We examined formalin-fixed paraffin-embedded specimens of colonic tissue for the expression of 10 selected candidate miRNAs. We performed receiver operating characteristic curve analysis, using area under the curve and a logistic regression model to evaluate the diagnostic and predictive power of the miRNA panels. Sixty patients were included in the final analysis. As a control group, 18 children without macroscopic and microscopic signs of inflammatory bowel disease were examined. The combination of three candidate miRNAs (let-7i-5p, miR-223-3p and miR-4284) enabled accurate detection of pediatric UC patients and controls. A panel of four candidate miRNAs (miR-375-3p, miR-146a-5p, miR-223-3p and miR-200b-3p) was associated with severity of UC in pediatric patients and a combination of three miRNAs (miR-21-5p, miR-192-5p and miR-194-5p) was associated with early relapse of the disease. Nine patients out of the total were diagnosed with primary sclerosing cholangitis (PSC) simultaneously with ulcerative colitis. A panel of 6 candidate miRNAs (miR-142-3p, miR-146a-5p, miR-223-3p, let-7i-5p, miR-192-5p and miR-194-5p) identified those patients with PSC. Specific combinations of miRNAs are promising tools for potential use in precise disease identification and severity and prognostic stratification in pediatric patients with ulcerative pancolitis.

Although necrotising enterocolitis (NEC) is a serious, life-threatening disease, improved neonatal care is increasing the number of survivors with NEC among extremely preterm neonates. Therapy is nevertheless mostly symptomatic and the mortality rate remains high, especially among neonates requiring surgery. Therefore, it is important to focus on preventing the disease and modifiable risk factors. NEC’s pathophysiology is multifaceted, with key factors being immaturity of the immune and barrier protective mechanisms of the premature gut and exaggerated proinflammatory reaction to insults like gut hypoxia, enteral nutrition or microbial dysbiosis. The role of the intestinal microbiome in the pathophysiology of NEC has been a subject of research for many years, but to date no specific pathogen or type of dysbiosis has been connected with NEC development. This review assesses current knowledge as to the role of the intestinal microbiota in the pathophysiology of NEC and the possibilities for positively influencing it

Background: Identifying novel diagnostic and prognostic biomarkers for pediatric inflammatory bowel diseases (PIBD), including Crohn’s disease (pCD) and ulcerative colitis (pUC), is essential for enhancing treatment outcomes. MicroRNAs (miRNAs) have been recognized for their broader relevance in PIBD pathogenesis. This study investigates their diagnostic potential and clinical utility in PIBD. Methods: This prospective, monocentric study, with retrospective validation, involved 119 PIBD patients (58 pCD, 61 pUC) and 39 non-IBD controls. Small RNA next-generation sequencing was performed on fresh-frozen gut biopsies, targeting histopathologically confirmed inflamed areas. Twenty-five dysregulated miRNA candidates were validated via RT-qPCR in formalin-fixed, paraffin-embedded gut biopsies. Logistic regression was used to establish diagnostic and prognostic miRNA expression signatures. Results: A diagnostic signature of 5 miRNAs (miR-223-3p, miR-34a-5p, miR-194-5p, miR-215-5p, miR-338-3p) distinguished pCD from non-IBD with 96.49% accuracy. Two miRNAs (miR-223-3p, miR-194-5p) differentiated pUC from non-IBD with 100% accuracy, and miR-215-5p distinguished pCD from pUC specimens with 83.54% accuracy. For treatment-naïve pCD patients, 7 miRNAs predicted residual disease activity at 3 months with 100% accuracy. Additionally, a distinct signature predicted the risk of relapse within 12 months with an accuracy of 84.21%. Conclusions: In this study, we have established tissue miRNA expression signatures with significant diagnostic and prognostic potential for use in PIBD. These findings aid in stratifying disease severity and risk, paving the way for more precise and personalized management of pediatric IBD.

Objectives: The identification of novel noninvasive diagnostic and prognostic biomarkers for pediatric inflammatory bowel disease (PIBD), including pediatric Crohn's disease (pCD) and ulcerative colitis (pUC), is crucial for improving therapeutic outcomes. Given their involvement in PIBD pathogenesis, microRNAs (miRNAs) represent promising candidates. This study investigates their potential diagnostic value and clinical utility. Methods: The study involved 81 treatment‐naive PIBD patients and 30 non‐IBD controls from whom stool samples were collected. Fecal microRNA analysis was performed using small RNA next‐generation sequencing. Differentially expressed miRNAs (DEMs) were identified in the exploratory phase (34 PIBD, 20 non‐IBD children). Logistic regression was used to establish diagnostic and prognostic miRNA expression signatures. The designed miRNA panels were validated using leave‐one‐out cross‐validation and on an independent cohort (47 PIBD, 10 non‐IBD children). Results: A diagnostic signature of four fecal miRNAs (10392‐5p, miR‐1246, miR‐4695‐5p, and miR‐5006‐5p) distinguished pCD from non‐IBD with 79.55% accuracy. Three fecal miRNAs (miR‐1290, miR‐3960, and miR‐5006‐5p) differentiated pUC from non‐IBD with 78.26% accuracy. For treatment‐naïve PIBD patients, panels of five and six miRNAs predicted residual disease activity at 3 months with 100% accuracy for pUC patients and 86.28% accuracy for pCD patients. Additionally, distinct signatures of four and six miRNAs predicted relapse within 12 months with accuracies of 96.87% (pUC) and 88.01% (pCD), respectively. Conclusion: We identified fecal miRNA expression profiles with strong diagnostic and prognostic value in PIBD. These results contribute to improved stratification of disease severity and risk, supporting the advancement of precision and personalized approaches in pediatric IBD management.