Biomarkers In Inflammatory Bowel Disease Research Articles

Effects of DNA methylation and its application in inflammatory bowel disease (Review).

Inflammatory bowel disease (IBD) is marked by persistent inflammation, and its development and progression are linked to environmental, genetic, immune system and gut microbial factors. DNA methylation (DNAm), as one of the protein modifications, is a crucial epigenetic process used by cells to control gene transcription. DNAm is one of the most common areas that has drawn increasing attention recently, with studies revealing that the interleukin (IL)‑23/IL‑12, wingless‑related integration site, IL‑6‑associated signal transducer and activator of transcription 3, suppressor of cytokine signaling 3 and apoptosis signaling pathways are involved in DNAm and in the pathogenesis of IBD. It has emerged that DNAm‑associated genes are involved in perpetuating the persistent inflammation that characterizes a number of diseases, including IBD, providing a novel therapeutic strategy for exploring their treatment. The present review discusses DNAm‑associated genes in the pathogenesis of IBD and summarizes their application as possible diagnostic, prognostic and therapeutic biomarkers in IBD. This may provide a reference for the particular form of IBD and its related methylation genes, aiding in clinical decision‑making and encouraging therapeutic alternatives.

C-reactive Protein: An Inflammatory Biomarker and a Predictor of Neurodegenerative Disease in Patients With Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) refers to two chronic conditions of the digestive tract: ulcerative colitis (UC) and Crohn's disease (CD), representing a progressive inflammatory process that mainly occurs in the gut, with frequent extra-intestinal manifestations. Even if remission is periodically obtained for some patients, the histological activity and digestive symptoms may continue, maintaining a persistent systemic inflammation that could induce further extra-intestinal complications and contribute to the development of neurodegenerative disease. C-reactive protein (CRP) is an acute-phase reactant that is widely accepted as a dominant serum biomarker in IBD. CRP consequently activates the complement cascade, supports the release of pro-inflammatory cytokines, and the clearance of microbial pathogens. All these processes facilitate further processes, including atherosclerosis and hypercoagulability, alteration of the intestinal microbiota, and the increased permeability of the intestinal barrier for neurotoxic substances produced by gut microorganisms, due to the presence of a high level of lipopolysaccharides. For IBD, the connection between intestinal inflammation and central nervous system inflammation could be explained through the activity of the vagus nerve, a carrier of cytokines, CRP, and toxic materials to the brain, potentially inducing vascular lesions and damage of the glial vascular unit, with further risk for degeneration within the central nervous system. CRP is a key marker for IBD pathogenesis and is able to dissociate into its monomeric form, mCRP, on contact with activated cell and tissue components via the systemic circulation. We hypothesize that the chronic inflammatory process within IBD could initiate neuroinflammation and neurodegeneration, and therefore, further investigation of the significance of chronically raised plasma of CRP and mCRP in patients with IBD is warranted, as it may represent a critical predictive factor associated with a later neurodegenerative risk. Any future initiative aimed at pharmacologic modulation of CRP (e.g., blocking CRP-mCRP dissociation), could represent a new therapeutic approach protecting against intestinal inflammation and concomitantly reducing the risk of neuroinflammation, neurodegeneration, and cognitive decline.

"Decoding inflammation: glycoprotein a repetition predominant, microRNA-142-3-p, and metastasis associated lung adenocarcinoma transcript 1: as novel inflammatory biomarkers of inflammatory bowel disease".

Inflammatory bowel disease (IBD) is a chronic gastrointestinal (GI) condition comprising Crohn's disease (CD) and ulcerative colitis (UC). The pathogenesis involves immune system dysregulation, with increased Th (T helper cell)17 cells and reduced regulatory T cell (Treg) differentiation. Transforming growth factor-β (TGF-β) secretion from Tregs helps control inflammation, and its production is regulated by glycoprotein-A repetition predominant (GARP) protein along with non-coding RNAs (ncRNAs) like microRNA(miR)-142-3p and metastasis associated lung adenocarcinoma transcript 1 (MALAT1) long non-coding RNAs (LncRNAs). This study analyzed their expression in IBD. Blood samples were collected from 44 IBD patients, and 22 healthy controls (HC). RNA extraction and circular DNA (cDNA) synthesis were performed. Real-time polymerase chain reaction (RT-PCR) measured gene expression of GARP, MALAT1, and miR-142-3p. Correlations and group differences were statistically analyzed. Compared to controls, GARP was downregulated while MALAT1 and miR-142-3p were upregulated significantly in IBD group. GARP and MALAT1 expressions positively correlated in controls. MALAT1 and miR-142-3p expressions positively correlated in IBD group. MALAT1 was downregulated in aged HC but upregulated with smoking history across groups. No correlations occurred between gene expression and gender, diet, infections, or disease activity scores. Dysregulation of GARP, MALAT1, and miR-142-3p likely contributes to inflammation in IBD by reducing TGF-β. MALAT1 is linked to smoking and age-related changes. These genes have potential as diagnostic markers or therapeutic targets for personalized IBD treatment.

Comprehensive profiling of the human fecal proteome from IBD patients with DIA-MS enables evaluation of disease-relevant proteins.

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), is characterized by chronic gastrointestinal inflammation. A high unmet need exists for noninvasive biomarkers in IBD to monitor changes in disease activityand guide treatment decisions. Stool is an easily accessed, disease proximal matrix in IBD, however the composition of the IBD fecal proteome remains poorly characterized. A data-independent acquisition LC-MS/MS approach was used to profile the human fecal proteome in two independent cohorts (Cohort 1: healthy n=5, UC n=5, CD n=5, Cohort 2: healthy n=20, UC n=10, and CD n=10) to identify noninvasive biomarkers reflective of disease activity. 688 human proteins were quantified, with 523 measured in both cohorts. In UC stool 96 proteins were differentially abundant and in CD stool 126 proteins were differentially abundant compared to healthy stool (absolute log2 fold change>1, p-value<0.05). Many of these fecal proteins are associated with infiltrating immune cells and ulceration/rectal bleeding, which are hallmarks of IBD pathobiology. Mapping the identified fecal proteins to a whole blood single-cell RNA sequencing data set revealed the involvement of various immune cell subsets to the IBD fecal proteome. Findings from this study not only confirmed the presence of established fecal biomarkers for IBD, such as calprotectin and lactoferrin, but also revealed new fecal proteins from multiple pathways known to be dysregulated in IBD. These novel proteins could serve as potential noninvasive biomarkers to monitor specific aspects of IBD disease activity which could expedite clinical development of novel therapeutic targets.

Prospective Evaluation of Serum Free Thiols in Inflammatory Bowel Disease: A Candidate to Replace C-Reactive Protein for Disease Activity Assessment?

Serum free thiols (SFTs) reflecting oxidative stress appear to correlate with inflammatory bowel disease (IBD) activity. We aimed to evaluate the performance of SFTs concentrations vs endoscopic and histological activity, compare SFTs with established biomarkers, and identify clinical and laboratory parameters independently associated with SFT levels in IBD patients. Patients with confirmed IBD undergoing routine ileocolonoscopy for activity assessment were prospectively recruited, with serum samples obtained concurrently for SFTs and routine bloods, plus fecal calprotectin and immunochemical tests were collected ±30 days from ileocolonoscopy. Endoscopic activity was assessed via established indices and histological activity graded as inactive/mild/moderate. Receiver-operating characteristic curve analyses were utilized to assess performance of SFTs vs endoscopic activity, and multiple regression analysis was used to identify factors associated with SFT levels. A total of 141 (80 Crohn's disease, 61 ulcerative colitis) patients were recruited. Median SFTs were significantly lower in moderate vs inactive/mild endoscopic activity (309 µM vs 433/471 µM, respectively; P < .01). There was no significant difference in median SFTs across inactive/mild/moderate histological activity. SFTs achieved higher sensitivity than C-reactive protein in predicting moderate, endoscopically active disease (89% vs 78%; area under the curve, 0.80 each) yet was outperformed by fecal calprotectin (100%; area under the curve, 0.93). Advancing age and increasing albumin levels were independently associated with SFT levels, and thus are possible confounders. This prospective study has demonstrated the potential of SFTs as a serum biomarker in IBD. It was more sensitive than C-reactive protein, yet less sensitive than fecal biomarkers for prediction of endoscopically active IBD.

Long noncoding RNAs and circular RNAs as potential diagnostic biomarkers of inflammatory bowel diseases: a systematic review and meta-analysis.

Inflammatory bowel disease (IBD) poses a growing global burden, necessitating the discovery of reliable biomarkers for early diagnosis. The clinical significance of dysregulated expression of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in diagnosing IBD has not been well established. Thus, our study aimed to investigate the diagnostic value of lncRNAs and circRNAs for IBD based on currently available studies. A comprehensive search was carried out in diverse electronic databases, such as PubMed, Embase, Scopus, Science Direct and Wiley Online Library to retrieve articles published until October 30, 2023. Stata 17.0 software was employed to determine pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic ratio (DOR), and area under the curve (AUC). Heterogeneity, subgroup analysis, and meta-regression were explored, and publication bias was assessed using Deeks' funnel plot. Fagan's nomogram and likelihood ratio scattergram were employed to evaluate the clinical validity. A total of 11 articles encompassing 21 studies which involved 1239 IBD patients and 985 healthy controls were investigated. The findings revealed lncRNAs exhibit high level of pooled sensitivity 0.94 (95% CI: 0.87-0.97) and specificity 0.99 (95% CI: 0.89-1.00), along with PLR, NLR, DOR, and AUC values of 64.25 (95% CI: 7.39-558.66), 0.06 (95% CI: 0.03-0.13), 1055.25 (95% CI: 70.61-15770.77), and 0.99 (95% CI: 0.97-0.99), respectively. Conversely, CircRNAs showed moderate accuracy in IBD diagnosis, with sensitivity of 0.68 (95% CI: 0.61-0.73), specificity of 0.73 (95% CI: 0.65-0.79), PLR of 2.47 (95% CI: 1.94-3.16), NLR of 0.45 (95% CI: 0.38-0.53), DOR of 5.54 (95% CI: 3.88-7.93), and AUC value of 0.75 (95% CI: 0.71-0.79). Moreover, findings from subgroup analysis depicted heightened diagnostic efficacy when employing lncRNA H19 and a large sample size (≥100), with notable efficacy in diagnosing both ulcerative colitis (UC) and Crohn's disease (CD). LncRNAs exhibit high diagnostic accuracy in distinguishing patients with IBD from healthy controls signifying their possible use as potential biomarkers, while circRNAs showed moderate diagnostic accuracy. Nevertheless, to validate our findings and confirm the clinical utility of lncRNAs and circRNAs in IBD diagnosis, a large pool of prospective and multi-center studies should be undertaken. https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023491840.

Bile acid profiling as an effective biomarker for staging in pediatric inflammatory bowel disease

ABSTRACT Rapid and accurate clinical staging of pediatric patients with inflammatory bowel disease (IBD) is crucial to determine the appropriate therapeutic approach. This study aimed to identify effective, convenient biomarkers for staging IBD in pediatric patients. We recruited cohorts of pediatric patients with varying severities of IBD to compare the features of the intestinal microbiota and metabolites between the active and remitting disease stages. Metabolites with potential for staging were targeted for further assessment in both patients and colitis model mice. The performance of these markers was determined using machine learning and was validated in a separate patient cohort. Pediatric patients with IBD exhibited distinct gut microbiota structures at different stages of disease activity. The enterotypes of patients with remitting and active disease were Bacteroides-dominant and Escherichia-Shigella-dominant, respectively. The bile secretion pathway showed the most significant differences between the two stages. Fecal and serum bile acid (BA) levels were strongly related to disease activity in both children and mice. The ratio of primary BAs to secondary BAs in serum was developed as a novel comprehensive index, showing excellent diagnostic performance in stratifying IBD activity (0.84 area under the receiver operating characteristic curve in the primary cohort; 77% accuracy in the validation cohort). In conclusion, we report profound insights into the interactions between the gut microbiota and metabolites in pediatric IBD. Serum BAs have potential as biomarkers for classifying disease activity, and may facilitate the personalization of treatment for IBD.

Repercussion of inflammatory bowel disease on lung homeostasis: The role of photobiomodulation.

Inflammatory bowel diseases (IBD) are chronic and multifactorial diseases characterized by dysfunction of the intestinal mucosa and impaired immune response. Data show an important relationship between intestine and respiratory tract. The treatments of IBD are limited. Photobiomodulation (PBM) is an effective anti-inflammatory therapy. Our objective was to evaluate the repercussion of IBD as well as its treatment with PBM on pulmonary homeostasis. Male Wistar rats were submitted to IBD induction by acetic acid and treated or not with PBM. Rats were irradiated with red LED on both right and left sides of the ventral surface and beside the external anal region during 3 consecutive days (wavelenght 660nm, power 100 mw, total energy 15J and time of irradiation 150s per point). Our results showed that IBD altered pulmonary homeostasis, since we observed an increase in the histopathological score, in myeloperoxidase activity (MPO), in mast cell degranulation, and in the release and gene expression of cytokines. We also showed that PBM treatment reduced biomarkers of IBD and reverted all augmented parameters in the lung, restoring its homeostasis. Thus, we confirm experimentally the important gut-lung axis and the role of PBM as a promising therapy.

P421 The faecal biomarker LDN-051 is a novel tool for monitoring disease activity and therapeutic response in Inflammatory Bowel Diseases

Abstract Background Crohn’s disease and ulcerative colitis, two forms of inflammatory bowel disease (IBD) require lifelong treatment and patient monitoring. Current predictors of relapse and therapeutic success have limitations, therefore there is high unmet need to identify novel biomarkers in IBD. Monitoring approaches for IBD are mostly invasive, time-consuming, and expensive. Therefore, a simple, rapid, and non-invasive test, with ability to differentiate IBD from other gastrointestinal conditions and to monitor disease activity, will have important clinical implications. Our previous mucosal cytokine profiling identified that Plasminogen activator inhibitor type 1 (PAI-1) is expressed in IBD patients with active disease, but not in control. Therefore, our aim was to assess the utility of PAI-1 in monitoring disease activity and therapeutic response of IBD patients in different biological samples. Methods Serum, biopsy and faecal samples were collected from 132 IBD patients and 30 controls without IBD. ELISA method was used to define the level of PAI-1 in the mucosa, serum, and faecal samples and the serum CRP levels were also determined. For the mucosal gene expression analysis qRT-PCR was used. The correlation and ROC analyses were applied to observe the relationship between the disease activity and PAI-1 level. Results The applied screening approach detected significant higher expression of PAI-1 in active IBD. We demonstrated that the serum, mucosal and faecal PAI-1 concentration was significantly elevated in IBD patients showing clinical and endoscopic activity. Additionally, in responder patients the initial PAI-1 level decreased significantly upon successful therapy, whereas it remained unchanged in non-responders. We also showed that faecal PAI-1 selectively increases in active IBD patients, but not in other organic gastrointestinal diseases. In addition, the stability analysis of faecal PAI-1 showed that the protein was detectable up to one week at room temperature and 4ºC. The serum, mucosal and faecal PAI-1 level showed positive correlation to the endoscopic activity. ROC curves demonstrated that faecal PAI-1 showed a relatively high power to distinguish between active and control patients. However, the serum CRP level no reflected to the therapeutic response. Conclusion Our results suggest that serum, mucosal and faecal PAI-1 expression reflects to the disease activity in IBD, which could be used to disease monitoring and possibly therapeutic response. The correlation between the faecal PAI-1 level and the endoscopic activity promotes that it could be used as a novel non-invasive disease specific faecal biomarker in the IBD diagnosis.

P317 Diagnostic accuracy of plasma calprotectin and serum calprotectin in patients with suspected Crohn’s disease

Abstract Background Faecal calprotectin is a sensitive marker for chronic inflammatory bowel disease (IBD), and it correlates with the endoscopic disease activity. However, patient reluctance and handling in the laboratory are limitations for the clinical use, and there is a need for new reliable blood-based biomarkers. Prior studies indicate, that serum calprotectin (SCal) and plasma calprotectin (PCal) can be used as biomarkers for IBD, and SCal correlates better with disease activity in Crohn’s disease (CD) than in ulcerative colitis. The aim of this study was to investigate the diagnostic accuracy of SCal and PCal in patients examined for CD. Methods Patients with clinically suspected CD were enrolled in a prospective, blinded, multicentre study examining non-invasive modalities for diagnosing CD (ClinicalTrials.gov identifier NCT03134586). Patients had a standardized work-up including ileocolonoscopy, pan-enteric capsule endoscopy and blood samples within a 2-week period. EDTA plasma was prepared less than 2 hours of sampling by centrifugation at 3000 g for 15 minutes. Samples were stored in a biobank at − 80°C until further analysis. A routine C-reactive protein (CRP) was measured on the same day. SCal and PCal were analysed in batches using the calprotectin assay product nr.1201 from Gentian (Moss, Norway) on the Cobas platform (Roche, Basel, Switzerland). Analyses were performed in an ISO 15189 accredited laboratory. Results 126 patients were enrolled in the study: 69 % women and 31 % men with a median age of 27.5 years (Table 1). A total of 57 (45%) patients were diagnosed with CD based on the result of ileocolonoscopy and pan-enteric capsule endoscopy. Patients with CD had a mean PCal of 0.50 mg/L (95% confidence interval (CI) 0.38-0.62) compared to 0.35 mg/L (CI 0.27-0.44) in non-CD patients (P = 0.03). The mean SCal was 1.45 mg/L (CI 1.20-1.69) and 1.06 mg/L (CI 0.90-1.22) in patients with and without CD, respectively (P = 0.01). Receiver operating characteristics curves showed an AUC of 0.63 (CI 0.53-0.73) for SCal and 0.61 (CI 0.51-0.71) for PCal, which was inferior to CRP (0.76, CI 0.68-0.85, P &amp;lt; 0.02) (Figure 1). In patients diagnosed with CD, SCal and PCal had a moderate correlation with CRP (rs = 0.47 and 0.55, respectively, P &amp;lt; 0.001), and SCal had a weak correlation with the Simple Endoscopic Score for CD (rs = 0.29, P = 0.04) and the Crohn’s Disease Activity Index (rs = 0.36, P = 0.03). Conclusion Levels of PCal and SCal are increased in patients with CD reflecting the systemic inflammatory response in this disease. However, SCal and PCal are insufficient biomarkers in patients with clinically suspected CD, and they are both inferior to CRP.

P418 Lipopolysaccharide-Binding Protein (LBP) in Crohn's Disease (CD) Patients: A Promising Non-Invasive Biomarker Monitoring Disease Activity

Abstract Background Current biomarkers of inflammatory bowel disease (IBD) monitoring (serum C-reactive protein (CRP) and faecal calprotectin (FC)) have limitations in terms of specificity (SP) and sensitivity (SE), especially for Crohn’s disease (CD) patients. Lipopolysaccharide-binding protein (LBP) is a soluble acute-phase protein and is thought to partly reflect intestinal permeability by binding to bacterial lipopolysaccharides. The search for new biomarkers to monitor disease activity would improve the management of IBD patients. Methods This is a retrospective study including 69 IBD patients (43 CD and 26 ulcerative colitis (UC)) and 21 healthy controls (HC). Serum LBP levels were measured by enzyme-linked immunosorbent assay. Clinical, biological and endoscopic parameters were analysed for IBD patients. Statistical tests, including nonparametric tests and receiver operating characteristic (ROC) curve analysis, were used to evaluate the diagnostic accuracy of LBP. Results Demographics and baseline data of the overall cohort is presented in Table 1. IBD patients displayed a significantly higher LBP median (29.6 µg/mL [19.8-38.8] in CD and 22.8 [13.7-38.8] in UC) than HC (5.5 [4.4-6.5], P &amp;lt; 0.001) with no overlapping distributions, a finding supported by an AUC of 0.997 and 0.989, respectively for CD and UC patients (Figures 1A). In CD patients, LBP levels gradually increased with endoscopic severity, demonstrating a 1.7-fold rise in active patients compared to remitter patients (P=0.02) (Figure 1B). LBP levels were higher in Montreal B1 compared to B2 and B3 CD patients (P &amp;lt; 0.001) (Figure 1C). Overall, a robust correlation was observed between LBP and CRP (ρ=0.75, P &amp;lt; 0.001). The correlation increased upon the exclusion of cases with normal CRP levels but active endoscopic disease (ρ=0.79, P &amp;lt; 0.001). In those endoscopically active patients with normal CRP, LBP level was higher than in remitter patients (34.3 [29.4-37.6] vs 19.1 [10-24.7], P=0.01) with a discriminative cut-off of 25 µg/mL (SE of 100%, SP of 89%). Likewise, LBP level exhibited a positive correlation with FC (ρ=0.42, P &amp;lt; 0.01) which was further strengthened after excluding cases where FC measurements did not align with endoscopic activity (ρ=0.53, P &amp;lt; 0.01). The median LBP for those patients was 25.6 [18.5-31.5], reflecting again the interest of LBP measurement to evaluate CD activity when FC lacks sensibility. Conclusion Our study suggests that LBP might be a promising non-invasive biomarker for monitoring disease activity, especially in CD patients. Furthermore, in clinical situations where current biomarkers (CRP and FC) lack sensitivity for assessing disease activity, LBP could be discriminative and help filling the gap for reliable therapeutic decisions.

P137 Salivary calprotectin: a potential biomarker in inflammatory bowel disease?

Abstract Background Background: Biomarkers are used frequently for evaluation and monitoring of IBD. Fecal calprotectin (FCP) is an already established biomarker in IBD, nevertheless patients often do not feel comfortable with stool manipulation. A saliva sample collection is particularly interesting due to its noninvasiveness and readiness of collection. We aimed to assess if salivary calprotectin (SCP) could be used as a new biomarker to assess disease activity. Methods In this observational cohort study, saliva was collected through the passive drool technique from adult IBD patients. All patients were submitted to a previous oral examination performed by a dentist. Recent history of antibiotic treatment (within the preceding month), proton pump inhibitors or non-steroidal anti-inflammatory drugs were exclusion criteria. Determination of FCP and SCP levels was accomplished using Elia Stool Extraction Kit and Elia Calprotectin 2 test. Intestinal disease activity was assessed with fecal calprotectin levels and the Harvey-Bradshaw Index (HBI) or Partial Mayo score (PMS). Ethical approval was obtained. Results 92 patients (56 with CD and 36 with UC) were included. Clinical characteristics are presented in Table 1. Patients had a median FCP of 45 mg/Kg and a median SCP of 206.5 mg/Kg. No significant correlations between SCP and FCP, CRP (C-reactive protein), ferritin and ESR (erythrocyte sedimentation rate) were found. However, there was a significant correlation between fecal calprotectin and CRP (p&amp;lt;0.001) and ESR (p=0.011). Disease activity scores did not correlate significantly with SCP, although there was a significant correlation between FCP and PMS (p=0.006). IBD patients were stratified based on a composite criterion for inactive disease HBI score &amp;lt;5 for CD or a PMS ≤ 2 for UC, and FCP cutoff value of 150 mg/Kg), with no significant difference in SCP between the two groups, despite the significant difference in FCP (p&amp;lt;0.001). No significant differences between different treatments groups or no treatment in salivary calprotectin concentration were found using Kruskal–Wallis H tests (CD (χ2(4) = 6.211, p = 0.184; UC group (χ2(3) = 1.201, p = 0.753)). 77% of patients with IBD do not have periodontal health. Nonetheless, there was no significant difference in the median SCP value between patients with or without periodontal health. Although the median SCP value was higher in patients with UC without periodontal health, the difference was not statistically significant (0.484). Conclusion SCP does not correlate with FCP and do not represent a reliable biomarker to distinguish disease activity in patients with IBD patients. Moreover, according to our results, it cannot be used as a marker of lack of oral health, namely periodontitis.

P140 Serum Metabolomic Biomarkers Can Identify and Characterize Associated Subtypes and Phenotypes in Inflammatory Bowel Disease

Abstract Background Metabolomics is increasingly recognized for uncovering pathophysiology and identifying diagnostic and prognostic biomarkers in inflammatory bowel disease (IBD). This study focuses on exploring comprehensive serum metabolomic profiles and corresponding specific metabolic pathways, in order to differentiate IBD patients from healthy individuals and to accurately identify IBD subtypes (Crohn's disease [CD], ulcerative colitis [UC]) through serum biomarkers with high patient acceptability. Methods Serum samples with matched clinical metadata were comprehensively collected from patients with IBD at Kyung Hee University Hospital, Seoul, Korea. Corresponding samples from normal controls (NCs) were obtained for comparison. Untargeted profiling was performed with Gas Chromatography-Time-Of-Flight-Mass Spectrometry, and targeted profiling of bile acids and tryptophan used Liquid Chromatography-Triple Quadrupole-Mass Spectrometry. The identification of distinct metabolites and potential biomarkers was achieved through extensive univariate and multivariate statistical analyses. Receiver operating characteristic (ROC) curves and metabolic pathway analyses were also conducted. Results A total of 346 subjects were analyzed, comprising 258 IBD patients (134 with CD and 124 with UC) and 88 NCs, Table 1. The patients with IBD were clearly clustered from the NCs, while IBD subgroups were not clearly separated from each other in the nontargeted profiling. Tryptophan and indole-3-acetic acid were elevated in both patients with CD and UC, while kynurenine and indole-3-propionic acid increased only in CD. Conversely, patients with UC had lower levels of indole-3-acetic acid, serotonin, and acetylcholine compared to CD. The ratio of primary and secondary bile acids was also significantly decreased in both patient groups compare with NCs. The ROC curves (Figure 1A) showed good discriminatory power for NCs vs CD (AUC:0.9738), NCs vs UC (AUC:0.9887), and UC vs CD (AUC:0.7140). Pathway analysis of the identified metabolites showed a sustained change in glyoxylate and dicarboxylate metabolism/alanine, aspartate and glutamate metabolism/glycine, serine and threonine metabolism associated with all comparisons (NCs vs UC, NCs vs CD, UC vs CD). Beta-alanine, arginine, and proline metabolism were linked to IBD compared to NCs. Glycerolipid metabolism distinctly differed between UC and CD (Figure 1B-1D). Network analysis revealed associations between metabolomic markers and specific clinical phenotypes of IBD subtypes. Conclusion This study demonstrates that serum metabolomic biomarkers are novel and effective tools for diagnosing IBD, as well as for identifying and characterizing its subtypes and associated phenotypes.

P096 Human extrachromosomal circular DNA is an emerging biomarker in Inflammatory Bowel Disease

Abstract Background Inflammatory Bowel Diseases (IBD) are chronic multifactorial disorders, which affect the gastrointestinal tract, including Ulcerative Colitis (UC) and Crohn’s Disease (CD). The existence of extrachromosomal circular DNA fragments (eccDNA) is well established, and it arises from all parts of the genome. eccDNA has mainly been studied in the context of cancer and not in relation to other diseases, and it has become a promising diagnostic and prognostic biomarker for different types of cancer. Herein, we investigate for the first time the role of eccDNA in IBD. Methods Forty consecutive IBD patients (19 CD, 21 UC) and 13 HC were enrolled, who underwent screening colonoscopy were prospectively enrolled at our center in this observational, case-controlled study. In IBD patients, disease activity was assessed using PMS and MES for UC, and HBI and SES-CD for CD. Colonic biopsies were collected from both inflamed and healthy mucosa in IBD patients and from HC. eccDNA was enriched, sequenced, and identified with Circle Finder from intestinal biopsies. Results Colonic mucosal samples from IBD patients showed increased average of eccDNAs, across all chromosomes than samples from HC. Furthermore, there was a slight yet significant tendency for larger eccDNAs in IBDs compared to HCs. Focusing on eccDNA coming from genic elements ("genic eccDNAs"), approximately 60% were fragments from protein coding genes, 32% from non-coding RNAs and 8% from pseudogenes. IBD patients had, on average, significantly more genic eccDNAs in their intestines as compared to HC. Moreover, IBD in remission had fewer eccDNAs in their intestines than active disease, although not statistically significant. eccDNAs from phosphodiesterase genes and genes involved in lipid metabolism were enriched in patients with active IBD than patients in remission. eccDNA from inflamed mucosa (both in UC and in CD) show an enrichment of genes related to inflammatory and immune pathways, such as MAPK, mTOR, ErB, Rap-1 and cGMP (SPOKE3, GRID2, DLEU1, ITGA8, NRG1). Conclusion We are the first to uncover an IBD-specific pattern of eccDNA production. Furthermore, we identified genic hotspots which characterize active vs. inactive disease and inflamed vs. healthy colonic tissue. We propose that eccDNA identification could be a promising new diagnostic marker for IBD patients.

P1228 The EISER Study: Identifying Microbial Factors Associated with Subclinical Gut Inflammation in Psoriatic Arthritis Patients Who Develop Inflammatory Bowel Disease

Abstract Background Nearly 8% of patients with spondyloarthritis (SpA) manifest symptoms that are compatible with active inflammatory bowel disease (IBD). It is well established that microbial dysbiosis is associated with different immune-mediated diseases. We therefore hypothesized that the gut microbiome could be a modulator of intestinal inflammation and factor in the pathogenesis of IBD in SpA patients. Methods As part of the EISER study, we selected a subset of 193 subjects diagnosed with psoriatic arthritis (PsA), a form of SpA, who had no prior diagnosis of IBD. The presence of subclinical symptoms compatible with IBD was evaluated at time of enrollment. For patients with fCAL levels of 80 µg/g or higher, colonoscopy was performed and histological analysis of biopsies collected during the procedure were used to diagnose IBD. Capsule endoscopy was performed on those patients with a negative colonoscopy result. Stool samples were collected from all participants, and microbial DNA was extracted for shotgun metagenomic sequencing using the Illumina HiSeq platform. Sequenced data was processed using MetaPhlAn 4 to estimate taxonomic composition, MMEDS for overall microbiome analysis, and R for additional statistical analyses. Results Twenty-five out of 193 subjects in our cohort (12.95%) had symptoms that were compatible with subclinical IBD (sIBD) and five patients (2.6% of total) were confirmed to have clinical IBD (cIBD). The use of nonsteroidal anti-inflammatory drugs (NSAIDs) resulted in significant differences in overall alpha (Shannon entropy, p=0.03) and beta microbial diversity (PERMANOVA, p=0.043), while the use of proton-pump inhibitors (PPI) resulted in significant differences in beta diversity (PERMANOVA, p= 0.036). Patients with cIBD had significantly higher abundance of taxa including Prevotella copri and Prevotella stercorea. P. copri, P. stercorea and fCAL were all significantly elevated in cIBD patients (Wilcoxon’s p=0.0278, 0.0007, 0.0161), although with a larger effect size in P. copri and P. stercorea (Cohen’s D: P. copri = 1.074; P. stercorea = 1.269; fCAL= 0.629). fCAL was also significantly elevated in patients who used PPIs (p= 4.456e-11), while P. copri and P. stercorea abundances were not impacted (Wilcoxon’s p: P. copri = 0.2394; P. stercorea = 0.0643). Conclusion Microbiome composition was impacted by the use of NSAIDs and PPI. We identified taxa differentially enriched in cIBD patients, including Prevotella copri and P. stercorea. Importantly, while fCAL was significantly higher in cIBD patients, its discriminatory power was not as strong as that of P. copri and P. stercorea, suggesting that these taxa could be potentially used as biomarkers of co-morbid IBD in patients with PsA.

Serum Amyloid A as a Potential Biomarker in Inflammatory Bowel Diseases, Especially in Patients with Low C-Reactive Protein.

The acute phase protein Serum Amyloid A (SAA) is synthesised by the liver in response to inflammatory stimuli. Previous studies have revealed that SAA may be a better biomarker of disease activity in inflammatory bowel disease (IBD) compared to C-reactive protein (CRP). This retrospective monocentric study evaluated whether SAA correlates with biomarkers like faecal calprotectin (FC), CRP, the Neutrophil to Lymphocyte ratio (NLR), the platelet count and clinical disease activity of IBD patients. Serum samples from the IBD outpatient clinic of the University Hospital Heidelberg were analysed for SAA concentrations if an FC concentration measurement was available from ±14 days to collection of the serum sample. Three hundred and six serum samples from 265 patients (166 with Crohn's disease, 91 with ulcerative colitis and 8 with IBD unclassified) met the inclusion criteria. There was a significant positive correlation between SAA and FC, CRP, NLR, platelet count and the Simple Clinical Colitis Activity Index (SCCAI). The cut-off for SAA serum concentration at 4.55 mg/L achieved a sensitivity of 57.5% and a specificity of 69.7% for the detection of active inflammation in IBD. SAA may be used as an additional biomarker in the disease monitoring strategy of IBD patients, especially in patients with low CRP concentrations.

Circulating miR-199a and long noncoding-RNA ANRIL as Promising Diagnostic Biomarkers for Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), involving both Crohn's disease (CD) and ulcerative colitis (UC), represents a chronic, immune-mediated inflammatory disease due to an uncontrolled, ongoing inflammatory response to intestinal bacteria in those with genetic susceptibility. MicroRNA (miRNA) extrusion from relevant remote organs or tissues is reflected in the expression of miRNAs in serum and plasma. Both UC and CD patients had higher blood levels of expressed miR-199a. Long noncoding RNA (lncRNA) ANRIL is a proinflammatory gene that mediates nuclear factor κB to play a role in inflammatory diseases, such as IBD. The aim of the current study is to investigate the potential role of both miR-199a and ANRIL in diagnosing IBD in adult patients. Sixty-seven IBD patients diagnosed clinically, radiologically, endoscopically, and histologically were included in this prospective cohort study. Participants were classified into 3 groups: the UC group (n = 35), the CD group (n = 32), and the control group (n = 30). Demographics, history taking, laboratory characteristics, and treatments were recorded. Tumor necrosis factor α, miR-199a, and ANRIL were measured. The findings suggested that miR-199a and ANRIL might be associated with the occurrence or progression of IBD because both genes were substantially expressed in the peripheral blood of patients with this condition. Receiver-operating characteristic curve analysis indicated that the detection of miR-199a and ANRIL had a predictive sensitivity of 62.9% and 88.6% and a specificity of 70.7% and 96.7% for the occurrence of UC cases, respectively, and a predictive sensitivity of 72.4% and 46.9% and a specificity of 96.7% and 34.7% for the occurrence of CD cases, respectively. Both miR-199a and ANRIL are abundant in the sera of IBD adult Egyptian patients (UC and CD). Both can represent a noninvasive marker for early disease diagnosis.

Biomarkers in inflammatory bowel disease: a practical guide.

Inflammatory bowel disease (IBD), comprising ulcerative colitis (UC) and Crohn's disease (CD), is a costly condition in terms of morbidity and healthcare utilization, with an increasing prevalence now approaching 1% in the Western world. Endoscopic assessment of IBD remains the gold standard for diagnosis, evaluation of treatment response and determination of post-operative recurrence, but is expensive and invasive. Biomarkers can facilitate non-invasive disease assessment, with C-reactive protein and faecal calprotectin as the most widely available biomarkers in current clinical practice. This narrative review summarizes the evidence for their use in both UC and CD and offers practical guidance for healthcare providers taking into account the limitations of biomarker interpretation. We present evidence for the future use of novel biomarkers in IBD and discuss how biomarker discovery could deliver the goal of precision medicine in IBD.

Traces of Canine Inflammatory Bowel Disease Reflected by Intestinal Organoids.

Inflammatory bowel disease (IBD) is a chronic inflammatory condition that affects humans and several domestic animal species, including cats and dogs. In this study, we have analyzed duodenal organoids derived from canine IBD patients using quantitative proteomics. Our objective was to investigate whether these organoids show phenotypic traits of the disease compared with control organoids obtained from healthy donors. To this aim, IBD and control organoids were subjected to quantitative proteomics analysis via liquid chromatography-mass spectrometry. The obtained data revealed notable differences between the two groups. The IBD organoids exhibited several alterations at the levels of multiple proteins that are consistent with some known IBD alterations. The observed phenotype in the IBD organoids to some degree mirrors the corresponding intestinal condition, rendering them a compelling approach for investigating the disease and advancing drug exploration. Additionally, our study revealed similarities to some human IBD biomarkers, further emphasizing the translational and comparative value of dogs for future investigations related to the causes and treatment of IBD. Relevant proteins such as CALU, FLNA, MSN and HMGA2, which are related to intestinal diseases, were all upregulated in the IBD duodenal organoids. At the same time, other proteins such as intestinal keratins and the mucosal immunity PIGR were depleted in these IBD organoids. Based on these findings, we propose that these organoids could serve as a valuable tool for evaluating the efficacy of therapeutic interventions against canine IBD.

An intestinal-targeting near-infrared probe for imaging nitroreductase in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an intestinal disease that causes inflammation of the digestive tract, resulting in a lack of oxygen in the intestinal microenvironment. Within this hypoxic setting, nitroreductase (NTR) is overexpressed and serves as a valuable biomarker for IBD. To date, there are only a limited number of fluorescent probes developed for NTR detection in cases of colitis. Unfortunately, they are unable to target the intestinal site and specifically image IBD. In this work, an intestinal-targeting near-infrared fluorescence probe was designed and synthesized for imaging NTR in IBD. Following its interaction with NTR, Cy-CA displays a remarkable fluorescence off-on transition at 720 nm, achieving a detection limit of 20 ng/mL. The incorporation of cholic acid group into Cy-CA has notably enhanced its ability to target intestinal cells precisely. This modification has demonstrated the specific detection of NTR in living cells, making Cy-CA a potent tool for studying the degree of cellular hypoxia in intestinal cells. In addition, the probe is able to monitor changes in NTR levels in mice with dextran sulphate sodium (DSS)-induced IBD. As far as we know, this represents the novel fluorescent probe designed for both intestinal targeting and NTR detection. As a result, Cy-CA holds the promise as a valuable diagnostic tool, offering a novel approach to monitor NTR activity and diagnose IBD with high specificity and sensitivity.