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Integrative multi-omics analyses suggest a candidate microbial metabolite-associated host gene network in ulcerative colitis.

Ulcerative colitis (UC) is associated with gut microbial dysbiosis, but the host molecular alterations potentially linked to microbially derived metabolites remain incompletely understood. We integrated Mendelian randomization (MR), microbial metabolite annotation, computational target prediction, colonic transcriptomics, network analysis, and machine learning. MiBioGen microbiome GWAS data were used as exposures and FinnGen Release 12 ULCERENTER as the outcome. Metabolites linked to MR-prioritized taxa were retrieved from GutMGene, and human targets were predicted using SwissTargetPrediction and SEA. UC-related genes were defined by integrating differential expression analysis and WGCNA and then intersected with predicted metabolite targets. MR prioritized one family and eight genera showing nominal genetically supported associations with UC, but none remained significant after Benjamini-Hochberg FDR correction. Three prioritized genera were linked to 15 microbe-metabolite records, corresponding to 13 unique metabolites; nine were retained for target prediction, yielding 277 unique predicted human targets. Transcriptomic analysis identified 1,530 DEGs and a 312-gene MEgrey60 module, with 273 overlapping genes, producing 1,569 unique UC-related genes. Their intersection with the 277 predicted targets yielded 47 candidate genes. Enrichment analyses highlighted mainly metabolic and lipid-related processes. Random Forest showed the highest mean AUC across the two independent external benchmarking cohorts, and SHAP prioritized EPHX1, HSD17B2, IGFBP5, and MMP10. IBDome analysis showed inflammation-associated expression differences in these genes. This study provides a genomics-informed, hypothesis-generating framework that prioritizes candidate microbe-metabolite-host relationships in UC for future experimental validation.

Humans

Genome-wide Association Studies of the Pathogenic Sphingosine-1-Phosphate Gene in Ulcerative Colitis.

BACKGROUND: Ulcerative colitis (UC) is a chronic inflammatory bowel disease that can lead to malignancies over time. Sphingosine-1-phosphate (S1P) receptor signaling affects lymphocyte trafficking and vascular integrity, influencing intestinal inflammation. This study aimed to identify S1P-related key genes in UC. METHODS: Differentially expressed genes (DEGs) between the UC and control groups were analyzed in the GSE87473 (training) dataset. Genes overlapping between the DEGs and S1P-related genes were considered candidate genes. These genes were incorporated into machine learning algorithms and subjected to expression analysis to identify key genes. Gene functions were determined through a gene–gene interaction network, enrichment analysis, and immune cell infiltration analysis. In addition, transcription factor–mRNA and mRNA–miRNA–lncRNA networks were constructed. Finally, reverse transcription–quantitative polymerase chain reaction (RT-qPCR) was performed to evaluate the expression of key candidate genes in UC and control tissues. RESULTS: This study identified two key genes (SPHK2 and SPNS2) associated with UC. Notably, SPHK2 expression was lower and SPNS2 expression was higher in the UC group in both training and validation datasets and in clinical UC tissues (RT-qPCR). The area under the curve values of SPHK2 and SPNS2 exceeded 0.7 in both datasets, indicating that the genes had good diagnostic efficacy for UC. Consistently, the nomogram showed that the two genes had promising diagnostic value in UC. SPHK2 and SPNS2 were found to be localized to the plasma membrane. The correlations of the two genes with different immune cells showed significantly opposite trends. In particular, SPHK2 had the strongest positive correlation with M2 macrophages (r = 0.6) and the strongest negative correlation with neutrophils. Moreover, mRNA–miRNA–lncRNA and transcription factor– mRNA networks of the key genes were constructed. CONCLUSION: This study suggests that SPHK2 and SPNS2 are key genes associated with UC, highlighting their potential as effective diagnostic biomarkers.

Humans

Shared CD4+ T cell receptor specificity groups in Crohn's disease and ulcerative colitis.

Inflammatory bowel disease (IBD), encompassing ulcerative colitis (UC) and Crohn's disease (CD), is marked by chronic intestinal inflammation and dysregulated immunity. Although UC and CD affect different areas of the gastrointestinal tract, both diseases share aberrant CD4+ memory T cell responses, with HLA-DRB1 as a major genetic risk factor. HLA-DRB1 encodes MHC class II molecules that influence the CD4+ T cell receptor (TCR) repertoire, yet how these genotypes shape TCR specificity in IBD remains unclear. Here, we genotyped HLA-DRB1 and profiled 3.13 million TCRβ sequences from circulating memory CD4+ T cells in 33 IBD patients (20 UC, 13 CD) and 14 healthy controls. Using the GLIPH2 algorithm, we distilled 468,441 candidates based on CDR3 amino acid motifs into 440 high-confidence TCR specificity groups significantly enriched among individuals sharing HLA-DRB1 alleles. Notably, 5 specificity groups were IBD-enriched and were shared between UC and CD, suggesting common antigen targets in both diseases. We also observed increased frequencies of clonally expanded cytotoxic GZMB+PRF1+ memory CD4+ T cells and KIR+CD8+ T cells in a subset of risk-allele carriers with IBD. These findings elucidate distinct, HLA-linked TCR specificity groups in IBD and provide mechanistic insights that may advance antigen discovery and personalized medicine.

Humans

Role of myeloid cells in mediating the effects of lipids on ulcerative colitis.

OBJECTIVE: To evaluate the causal relationship between lipids and ulcerative colitis (UC) through Mendelian Randomization (MR), and to further investigate the involvement of immune cells in mediating this process. METHODS: Utilizing summary statistics from genome-wide association studies (GWAS) of individuals with European ancestry, we analyzed the causal link between 179 lipid types and UC (2,569 UC cases and 453,779 controls) through Two-sample Mendelian randomization (2SMR) and Bayesian-weighted MR (BWMR). Based on this, a mediation screening of 731 immune cell phenotypes was conducted to identify exposure and mediator factors. Lastly, the role and proportion of immune cells in mediating the causal effects of lipids on UC were assessed via reverse MR (RMR) and two-step MR. RESULTS: The results of MR showed that there was a causal relationship between the six genetically predicted lipid types and UC (P <0.05), and the four immune cell phenotypes were identified as mediators of the association between lipids and UC. Notably, Phosphatidylcholine (PC) (16:0_0:0) served as the exposure factor, and myeloid cells CD11b on CD33+ HLA DR+ CD14dim acted as the mediator. Mediation analysis showed that CD11b on CD33+ HLA DR+ CD14dim had a mediation effect of -0.0205 between PC (16:0_0:0) and UC, with the mediation effect ratio at 15.38%. CONCLUSION: Our findings elucidate the causal effect of lipids on UC and identify the significant mediating role of myeloid cells CD11b on CD33+ HLA DR+ CD14dim in regulating UC through PC (16:0_0:0), offering new pathways and strategies for UC clinical treatment.

Humans

Day 3 Oxford criteria predict steroid non-response for acute severe ulcerative colitis in the post biologic era.

BACKGROUND AND AIMS: Outcomes of patients admitted with acute severe ulcerative colitis (ASUC) in the post biologic era are under explored, as well as the ability of scoring indices to predict early steroid non-response. METHODS: This retrospective cohort study included adults hospitalized with ASUC (2010-2022) at London Health Sciences Centre, Canada. Steroid response, need for rescue therapy, colectomy during index hospitalization, and colectomy and hospitalization at 3- and 12-months following discharge was assessed. Logistic regression identified predictors of steroid non-response, defined as need for rescue therapy or colectomy during hospitalization. RESULTS: Of 261 adults hospitalized with ASUC (male: 51.7%, mean age: 40.6&#x2009;years), 71.2% had extensive colitis. After intravenous corticosteroid therapy during index admission, 55.7% (n&#x2009;=&#x2009;147) had a response, 37.9% (n&#x2009;=&#x2009;99) received rescue therapy (infliximab: 98, tofacitinib: 1, and cyclosporine: 0), and 8% (21/261) underwent colectomy. Additionally, 11.6% (28/240) of patients discharged from hospital underwent colectomy within the first 12&#x2009;months (8.3% at 3-months and 3.3% between 3 and 12&#x2009;months). There was no difference between steroid responders and non-responders for colectomy (11% vs 12.6%) or hospitalization (33.5% vs 32.6%) at 12&#x2009;months. The overall cumulative probabilities of colectomy for the entire cohort at 1&#x2009;year, 3&#x2009;years, and 5&#x2009;years were 13.5%, 16.1%, and 17.4%, respectively. On multivariate analysis, Day 3 Oxford criteria was the only factor found to be statistically significant in predicting steroid non-response (odds ratio 4.70, 95%CI [1.06-20.80]). CONCLUSIONS: Day 3 Oxford criteria was an independent predictor of steroid non-response. The risk of colectomy remains substantial after discharge despite low in-hospital colectomy rates following an episode of ASUC. Initial steroid response did not affect long-term colectomy rate at 12&#x2009;months.

Humans

EP300-mediated lactylation leads to ulcerative colitis via CD86-positive plasmacytoid dendritic cells: A Mendelian randomization and mediation analysis.

This study explores the potential mechanism between lactylation and ulcerative colitis (UC) using two-sample Mendelian randomization and multi-omics analysis. This study employed expression quantitative trait loci and protein quantitative trait loci as exposures, with UC from the Finnish database as the outcome, to conduct Mendelian randomization analysis on lactylation-related target genes, aiming to investigate the causal relationships between these exposures and the outcome. Sensitivity and pleiotropy tests, combined with colocalization analysis, are performed to identify the best target genes and ensure the robustness of the results. Finally, immune cells are included for mediation analysis between lactylation and UC to explore potential mechanisms of action. Through Mendelian randomization analysis combined with sensitivity and pleiotropy tests, 2 lactylation target genes were found to have a significant causal relationship with UC. Subsequent colocalization analysis confirmed EP300 as a potential gene target. After including immune cells in the mediation analysis, it was discovered that there is a potential mechanism involving EP300, CD86+ plasmacytoid dendritic cells (pDCs), and UC. There is a significant causal relationship between lactylation and UC. Furthermore, the lactylation-modified gene EP300 may lead to UC occurrence by regulating CD86+ pDCs.

Humans

Efficacy, Safety, and Pharmacokinetics of Upadacitinib Among Patients in East Asia With Moderately to Severely Active Ulcerative Colitis: A Post Hoc Subanalysis of Randomized Phase 3 Studies.

BACKGROUND AND AIM: Upadacitinib, a selective Janus kinase 1 inhibitor, is approved to treat moderately to severely active ulcerative colitis (UC). This post hoc subanalysis evaluated the efficacy, safety, and pharmacokinetics of upadacitinib in patients in East Asia. METHODS: U-ACHIEVE (UC1; NCT02819635) and U-ACCOMPLISH (UC2; NCT03653026) were Phase 3, multicenter, randomized, double-blind, induction studies evaluating upadacitinib 45&#x2009;mg or placebo daily in adults with moderately to severely active UC. Clinical responders to 8&#x2009;weeks of upadacitinib induction were eligible to receive upadacitinib 15&#x2009;mg, upadacitinib 30&#x2009;mg, or placebo daily in the 52-week U-ACHIEVE maintenance study (UC3; NCT02819635). Efficacy outcomes, safety, and pharmacokinetics were evaluated among East Asian patients. RESULTS: A higher proportion of East Asian patients achieved clinical remission with upadacitinib than placebo at induction Week 8 (UC1: n&#x2009;=&#x2009;127, 31.4% vs. 7.3%; UC2: n&#x2009;=&#x2009;114, 31.2% vs. 2.7%) and maintenance Week 52 (UC3: n&#x2009;=&#x2009;184, upadacitinib 15&#x2009;mg, 52.4%; upadacitinib 30&#x2009;mg, 53.8%; placebo, 10.7%). Rates of endoscopic outcomes were higher with upadacitinib than with placebo across studies. No new safety signals were identified. Herpes zoster occurrences were low (UC1 and UC2: upadacitinib 45&#x2009;mg, two events [in one patient]; placebo, zero events; UC3: upadacitinib 15&#x2009;mg, five events; upadacitinib 30&#x2009;mg, eight events; placebo, zero events). Pharmacokinetics and trends in the relationship between upadacitinib exposure and efficacy were consistent in the East Asian and global populations. CONCLUSION: Upadacitinib was generally well tolerated and effective for treating moderately to severely active UC in patients in East Asia, with a favorable benefit-risk profile consistent with the global population. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02819635, NCT03653026.

Humans

Effect of Chang'an decoction on ulcerative colitis by regulating T helper 17 cells and regulatory T cellsRab27 in the p53/high mobility group box 1 pathway.

OBJECTIVE: To explore the effect of Chang'an decoction (, CAD) of ameliorating the immune imbalances in ulcerative colitis (UC) by regulating Rab27 in the P53/high mobility group box 1 pathway. METHODS: The functions and important signaling pathways of the Rab27- and UC-related genes were analyzed viathe use of microarray data from the gene expression omnibus database, gene ontology database, Kyoto encyclopedia of genes and genomes database and gene set enrichment analysis. Dextran sulfate sodium salt-induced colitis mouse model was used to verify the bioinformatics results. Colon length, body weight, and disease activity index were measured. Hematoxylin and eosin staining was applied to validate the histopathology. Tight junction proteins were detected by immunohistochemistry. The proportions of T helper 17 cells (Th17) and regulatory T cells (Treg) in mesenteric lymph nodes were measured viaflow cytometry. Proinflammatory cytokines like interleukin (IL) 17 (IL-17), IL-21 and IL-22 and anti-inflammatory cytokines like transforming growth factor &#x3b2; and IL-10 in the serum and colon of mice were detected by enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction, respectively. The expression levels of high mobility group box 1 (HMGB1), P53 and phospho- P53 (P-P53) in colonic tissues were detected by immunofluorescence and Western blotting. RESULTS: Bioinformatics analysis revealed that compared with normal tissues, the expression of Rab27 was significantly increased in UC tissues. Receiver operating characteristic curve showed that Rab27 has the potential to be used as a biomarker for the diagnosis of disease activity. Enrichment analysis showed that UC and Rab27 were mainly associated with small molecule transport, nutrient metabolism, transmembrane transport and the downstream pathway of P53. According to animal experiments, the expression of Rab27 was increased in UC tissues, which aggravated the colonic pathological damage, activated the expression of HMGB1, and also leaded to the imbalance of Th17 and Treg cells. After CAD intervention, Rab27 overexpression, weight loss, colon shortening, and pathological damage were substantial reduced, the expression of tight junction proteins, zona occludens 1 and Occludin were increased. The effect of CAD at high-dose was more obvious. In addition, CAD upgraded the number of Treg cells and the production of TGF-&#x3b2; and IL-10, while decreasing the number of Th17 cells and the expression of inflammatory cytokines (IL-17, IL-21, and IL-22). Moreover, colon inflammation was alleviated by CAD, as indicated by the regulation of HMGB1 and P-P53 expression. CONCLUSION: The expression of Rab27, HMGB1 and P-P53 could be decreased by CAD, and the balance of Th17 and Treg cells as well as their related cytokines could be regulated by CAD.

Animals

Dolichocolon May Differentially Associate with Ulcerative Colitis Phenotype in Children.

BACKGROUND: Dolichocolon (DC) is an underrecognized anatomic variant associated with constipation; its association with ulcerative colitis (UC) is unknown. METHODS: We retrospectively reviewed abdominal MRI and CT scans in children with UC, Crohn's disease (CD), and non-inflammatory bowel disease (non-IBD) controls, classifying DC subtypes. RESULTS: A total of 111 cases (66 with UC) were examined. DC was similarly common (p&#x2009;=&#x2009;0.4436) in patients with constipated (69%) or non-constipated (NC-UC: 57%) UC. In non-constipated (NC) patients, DC prevalence was higher in children with UC than those with CD or controls. Type 1 DC predominated in NC children with proctitis/left-sided UC (E1/E2), while Type 2 DC was enriched in children with extensive/pancolitis (E3/E4). DISCUSSION: DC may be associated with different phenotypes of UC and may influence disease distribution independent of constipation. However, given the cross-sectional design of this study, these associations should be interpreted cautiously and require confirmation in longitudinal studies.

Humans

Lymphocyte-C-Reactive Protein Ratio as Promising New Marker for Predicting Surgical Site Infection in Children With Ulcerative Colitis.

BACKGROUND: Surgical site infection (SSI) is a major complication after ileal pouch-anal anastomosis (IPAA) in pediatric ulcerative colitis (UC), significantly impairing quality of life. The lymphocyte-to-C-reactive protein ratio (LCR), a composite marker of systemic inflammation and immune/nutritional status, has emerged as a potential predictor of postoperative outcomes. This study assessed the utility of preoperative LCR in predicting SSI in pediatric UC. METHODS: We retrospectively reviewed pediatric UC patients who underwent IPAA at Mie University Hospital between 2000 and 2024. Preoperative LCR values were analyzed, and the optimal cutoff for SSI prediction was determined using receiver operating characteristic (ROC) analysis. Multivariate logistic regression was performed to identify independent risk factors. SSI was defined according to CDC criteria within 30&#x2009;days postoperatively. RESULTS: Among 57 patients, 11 (19.3%) developed SSI. The incidence was higher in three-stage procedures than in two-stage procedures (22.7% vs. 17.1%). In both groups, preoperative LCR was significantly lower in SSI-positive patients. ROC analysis demonstrated good discrimination (AUC: 0.80), with an optimal cutoff of LCR <&#x2009;5000 (sensitivity: 90.9%, specificity: 71.7%). Multivariate analysis confirmed LCR <&#x2009;5000 as an independent predictor of SSI (odds ratio [OR]: 6.34, 95% CI: 1.23-48.2, p&#x2009;=&#x2009;0.027). CONCLUSION: Preoperative LCR is a simple, objective biomarker that reliably predicts SSI risk in pediatric UC patients undergoing IPAA. Incorporating LCR into preoperative risk stratification may enable personalized interventions, including nutritional optimization and tailored prophylaxis, to improve surgical outcomes.

inflammatory bowel disease

The complement system in inflammatory bowel disease: from early observations to emerging frontiers.

PURPOSE OF REVIEW: The complement system is one of the most evolutionarily conserved arms of innate immunity and has re-emerged as an important regulator of intestinal inflammation in inflammatory bowel disease (IBD). Early observations from the mid-1970&#x200a;s such as complement deposition in diseased bowel tissue and elevated serum complement levels in patients with ulcerative colitis and Crohn's disease have evolved into a nuanced understanding of how individual complement components can exert both protective and pathogenic effects in IBD. This review highlights recent advances in complement biology and examines how complement shapes intestinal immune responses, particularly in the setting of ongoing inflammation. RECENT FINDINGS: The complement system consists of more than 60 proteins that act as rapid first responders to infection. Although traditionally considered primarily liver-derived circulating effectors, recent work has demonstrated local synthesis and activation of key complement components at mucosal sites, including the colon. In parallel, genome-wide association studies have identified variants in complement genes associated with severe IBD complications. Collectively, these findings reveal a dichotomous role for complement in IBD, whereby excessive activation promotes inflammation, while impaired function compromises host defense and worsens disease outcomes. SUMMARY: Complement-targeted therapies have been effective in other diseases but have not yet translated to IBD. A deeper understanding of context-dependent protective versus pathogenic complement functions will be essential for developing future therapeutic strategies.

Humans

The impact for causal associations between common diseases and inflammatory bowel disease: a disease-wide bidirectional Mendelian randomization study.

OBJECTIVES: Observational studies on associations between various diseases and inflammatory bowel disease (IBD) are often limited by confounding and reverse causation. We aimed to assess potential causal relationships between a wide range of diseases and IBD, including Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We performed a comprehensive bidirectional Mendelian randomization (MR) analysis of 104 common diseases and IBD traits using the generalized summary-data-based MR (GSMR) approach. Genome-wide association study (GWAS) summary statistics for diseases were obtained from the MRC Integrative Epidemiology Unit, and IBD data from the International IBD Genetics Consortium. Summary-data-based MR (SMR) integrating GWAS and expression quantitative trait locus data was applied to identify pleiotropic genes associated with IBD. RESULTS: MR analyses identified 38, 34, and 52 exposures significantly associated with IBD, UC, and CD, respectively. Childhood- and adult-onset asthma showed distinct causal effects on UC and CD. Reverse MR indicated associations between IBD traits and 15 diseases, including multiple sclerosis. SMR identified RGS14 and CARD9 as pleiotropic genes linked to IBD, suggesting shared genetic mechanisms with asthma and multiple sclerosis. CONCLUSIONS: These findings provide evidence for causal links and shared immune-related genetic mechanisms underlying IBD, highlighting potential targets for future research.

Humans

Disparities in Outcomes for Patients With Inflammatory Bowel Disease at a Private vs Public Hospital in New York City.

BACKGROUND: In patients with inflammatory bowel disease (IBD), social determinants of health contribute to health inequalities. We aimed to compare patients with IBD treated at a private nonprofit vs public hospital in New York City. METHODS: We performed a retrospective study of adult patients with Crohn's disease or ulcerative colitis with established IBD care. Patient demographics, disease characteristics, healthcare utilization, treatment modalities, and clinical outcomes were collected. Using a series of linear mixed and logistic models, the differences between care at a private nonprofit vs public hospital were assessed while controlling for factors that differed between them. RESULTS: Our study included 418 patients with IBD, 209 from each hospital. Compared with public hospital patients, private hospital patients were more likely to be White, be non-Hispanic, and have private insurance (all P&#x2009;=&#x2009;.0005) and less likely to face housing instability (P&#x2009;<&#x2009;.0001), face unemployment (P&#x2009;=&#x2009;.0004), be current smokers (P&#x2009;=&#x2009;.03), or be foreign born (P&#x2009;<&#x2009;.0001). Patients at the private hospital were more likely to have multiple anti-tumor necrosis factor (P&#x2009;=&#x2009;.0001) and biologic use (P&#x2009;<&#x2009;.0001). Public hospital patients were less likely to be considered endoscopically adherent (odds ratio [OR], 0.377; P&#x2009;=&#x2009;.001) and more likely to visit the emergency department (OR, 5.01; P&#x2009;<&#x2009;.0001) and be hospitalized (OR, 1.92; P&#x2009;=&#x2009;.05). CONCLUSIONS: Our study is the first to identify significant differences in patient demographics, disease phenotype, treatments and clinical outcomes between patients treated for IBD at a private nonprofit vs public hospital. Our data suggest that social determinants of health drive disparities in the utilization of healthcare facilities.

Humans

Understanding disease-associated metabolic changes in human colonic epithelial cells using the iColonEpithelium metabolic reconstruction.

The colonic epithelium plays a key role in the host-microbiome interactions, allowing uptake of various nutrients and driving important metabolic processes. To unravel detailed metabolic activities in the human colonic epithelium, our present study focuses on the generation of the first cell-type-specific genome-scale metabolic model (GEM) of human colonic epithelial cells, named iColonEpithelium. GEMs are powerful tools for exploring reactions and metabolites at the systems level and predicting the flux distributions at steady state. Our cell-type-specific iColonEpithelium metabolic reconstruction captures genes specifically expressed in the human colonic epithelial cells. iColonEpithelium is also capable of performing metabolic tasks specific to the colonic epithelium. A unique transport reaction compartment has been included to allow for the simulation of metabolic interactions with the gut microbiome. We used iColonEpithelium to identify metabolic signatures associated with inflammatory bowel disease. We used single-cell RNA sequencing data from Crohn's Diseases (CD) and ulcerative colitis (UC) samples to build disease-specific iColonEpithelium metabolic networks in order to predict metabolic signatures of colonocytes in both healthy and disease states. We identified reactions in nucleotide interconversion, fatty acid synthesis and tryptophan metabolism were differentially regulated in CD and UC conditions, relative to healthy control, which were in accordance with experimental results. The iColonEpithelium metabolic network can be used to identify mechanisms at the cellular level, and we show an initial proof-of-concept for how our tool can be leveraged to explore the metabolic interactions between host and gut microbiota.

Humans

Risk relationship between inflammatory bowel disease and urolithiasis: A two-sample Mendelian randomization study.

BACKGROUND: The causal genetic relationship between common parenteral manifestations of inflammatory bowel disease (IBD) and urolithiasis remains unclear because their timing is difficult to determine. This study investigated the causal genetic association between IBD and urolithiasis using Mendelian randomization (MR) based on data from large population-based genome-wide association studies (GWASs). METHODS: A two-sample MR analysis was performed to assess the potential relationship between IBD and urolithiasis. Specific single nucleotide polymorphism data were obtained from GWASs, including IBD (n = 59957) and its main subtypes, Crohn's disease (CD) (n = 40266) and ulcerative colitis (UC) (n = 45975). Summarized data on urolithiasis (n = 218792) were obtained from different GWAS studies. A random-effects model was analyzed using inverse-variance weighting, MR-Egger, and weighted medians. RESULTS: Genetic predisposition to IBD and the risk of urolithiasis were significantly associated [odds ratio (OR), 1.04 (95% confidence interval [CI], 1.00-.08), P = 0.01]. Consistently, the weighted median method yielded similar results [OR, 1.06 (95% CI, 1.00-1.12), P = 0.02]. The MR-Egger method also demonstrated comparable findings [OR, 1.02 (95% CI, 0.96-1.08), P = 0.45]. Both funnel plots and MR-Egger intercepts indicated no directional pleiotropic effects between IBD and urolithiasis. CD was strongly associated with it in its subtype analysis [OR, 1.04 (95% CI, 1.01-1.07), P = 0.01], and UC was also causally associated with urolithiasis, although the association was not significant [OR, 0.99 (95% CI, 0.95-1.03), P = 0.71]. CONCLUSION: A unidirectional positive causal correlation was identified between IBD and urolithiasis, with varying degrees of association observed among the different subtypes of IBD. Recognizing the increased incidence of urolithiasis in patients with IBD is crucial in clinical practice. Early detection and surveillance of IBD, improved patient awareness, adoption of preventive strategies, and promotion of collaborative efforts among healthcare providers regarding treatment methodologies are vital for improving patient outcomes.

Humans

Microbial and functional shifts between flare and remission in a single-center cohort of children with inflammatory bowel disease.

BACKGROUND: Gut microbial dysbiosis is central to the pathogenesis of inflammatory bowel disease (IBD). While gut microbiome differences between patients with and without IBD are well established, microbiome changes associated with disease activity and remission remain limited, particularly in paediatric populations. AIM: To examine intra-individual taxonomic and functional gut microbiome changes during transition from active flare to remission under maintenance immunosuppression in a pilot single-center Singapore cohort of children with IBD. METHODS: Paired stool samples and clinical data were collected from seven patients with paediatric IBD [5 Crohn's disease (CD), 2 ulcerative colitis; &#x2264; 18 years] during active disease/flare (visit 1; Pediatric CD Activity Index/Pediatric Ulcerative Colitis Activity Index &#x2265; 10) and subsequent clinical remission (visit 2; Pediatric CD Activity Index/Pediatric Ulcerative Colitis Activity Index < 10). Samples underwent shotgun metagenomic sequencing for high-resolution taxonomic profiling and functional annotation of Kyoto Encyclopaedia of Genes and Genomes pathways. RESULTS: Gut microbial diversity was reduced during flare compared to remission, with Actinobacteria abundance significantly higher in remission. Two distinct microbial clusters differentiated flare and remission states: The remission cluster was enriched with Bifidobacterium adolescentis, Bifidobacterium dentium, Lactobacillus gasseri, Faecalibacterium prausnitzii, while the flare state showed increased Klebsiella pneumoniae. Remission was further characterized by a downregulation of pathogenic microbes and an upregulation of beneficial microbes including a higher abundance of the butyrate producer Anaerostipes hadrus (P = 0.046). Microbial functional genes enriched in remission were predominantly associated with metabolic pathways including vitamin and cofactor biosynthesis, as well as carbohydrate, amino acid, and lipid metabolism. CONCLUSION: The transition from flare to remission in Singaporean children with IBD is characterized by functional remodeling of the gut microbiome, which may contribute to recovery processes related to intestinal barrier integrity, cellular maintenance, and tissue repair. Targeted modulation of the gut microbiome may help sustain remission in paediatric IBD.

Functional shift

No causal relationship between glucose and inflammatory bowel disease: a bidirectional two-sample mendelian randomization study.

BACKGROUND: Association between glucose and inflammatory bowel disease (IBD) was found in previous observational studies and in cohort studies. However, it is not clear whether these associations reflect causality. Thus, this study investigated whether there is such a causal relation between elevated glucose and IBD, Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We performed a two-sample Mendelian Randomization (MR) with the independent genetic instruments identified from the largest available genome-wide association study (GWAS) for IBD (5,673 cases; 213,119 controls) and its main subtypes, CD and UC. Summarized data for glucose which included 200,622 cases and glycemic traits including HbA1c and type 2 diabetes(T2DM) were obtained from different GWAS studies. Primary and secondary analyses were conducted by preferentially using the radial inverse-variance weighted (IVW) approach. A number of other meta-analysis approach and sensitivity analyses were carried out to assess the robustness of the results. RESULTS: We did not find a causal effect of genetically predicted glucose on IBD as a whole (OR 0.858; 95% CI 0.649-1.135; P&#x2009;=&#x2009;0.286). In subtype analyses glucose was also suggestively not associated with Crohn's disease (OR 0.22; 95% CI 0.04-1.00; P&#x2009;=&#x2009;0.05) and ulcerative colitis (OR 0.940; 95% CI 0.628-1.407; P&#x2009;=&#x2009;0.762). In the other direction, IBD and its subtypes were not related to glucose and glycemic traits. CONCLUSIONS: This MR study is not providing any evidence for a causal relationship between genetically predicted elevated glucose and IBD as well as it's subtypes UC and CD. Regarding the other direction, no causal associations could be found. Future studies with robust genetic instruments are needed to confirm this conclusion.

Humans