Inflammatory Crohn Research Articles

Crohn's Disease is a Greater Risk Factor for Nonalcoholic Fatty Liver Disease Compared to Ulcerative Colitis: A Systematic Review.

Crohn's disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases that have been associated with nonalcoholic fatty liver disease (NAFLD). This systematic review aimed to examine whether Crohn's disease confers a greater risk for nonalcoholic fatty liver disease compared to ulcerative colitis. A comprehensive search of electronic databases from January 2000 to May 2023 was conducted to identify observational studies investigating the association between Crohn's disease or ulcerative colitis and nonalcoholic fatty liver disease. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 checklist ensured transparent reporting, and the Newcastle-Ottawa Scale was used to assess study quality. Data synthesis revealed higher nonalcoholic fatty liver disease prevalence among Crohn's disease patients compared to ulcerative colitis patients across regions. Ten studies published between 2016 and 2022, encompassing a total of 4164 participants from three continents, were included in the review. The median proportion of Crohn's disease patients with nonalcoholic fatty liver disease was 37.22% (range: 10.95-53.80%), while it was 27.55% (range: 8.60-46.20%) for ulcerative colitis patients. Subgroup analysis by region confirmed CD's higher NAFLD risk. Median proportions for CD patientswho developed NAFLD from North America, Europe, and Asia were 25.97% (range: 14.6-37.33%), 47.01% (range: 14.2-53.8%), and 20.78% (range: 10.95-30.6%), respectively, and the median proportion of persons with UC who developed NAFLD in studies from North America, Europe, and Asia were 17.28% (range: 8.6-25.96%), 37.70% (range: 25.64-46.20%), and 19.52% (range: 10.14-28.90%), respectively. Variations suggest differing mechanisms, disease features, and therapeutics. Transmural inflammation in Crohn's disease may increase metabolic abnormalities, including nonalcoholic fatty liver disease. Geographic differences in lifestyle, genetics, and environmental variables may also contribute. This review demonstrates that Crohn's disease patients face a higher nonalcoholic fatty liver disease risk than ulcerative colitis patients, emphasizing the need for early monitoring and prevention. Further studies are warranted to understand mechanisms and develop tailored management approaches.

An Intestinal Th17 Subset is Associated with Inflammation in Crohn's Disease and Activated by Adherent-invasive Escherichia coli.

IFNγ-producing ex-Th17 cells ['Th1/17'] were shown to play a key pathogenic role in experimental colitis and are abundant in the intestine. Here, we identified and characterised a novel, potentially colitogenic subset of Th17 cells in the intestine of patients with Crohn's disease [CD]. Human Th17 cells expressing CCR5 ['pTh17'] co-expressed T-bet and RORC/γt and produced very high levels of IL-17, together with IFN-γ. They had a gene signature of Th17 effector cells and were distinct from established Th1/17 cells. pTh17 cells, but not Th1/17 cells, were associated with intestinal inflammation in CD, and decreased upon successful anti-TNF therapy with infliximab. Conventional CCR5[-]Th17 cells differentiated to pTh17 cells with IL-23 in vitro. Moreover, anti-IL-23 therapy with risankizumab strongly reduced pTh17 cells in the intestine. Importantly, intestinal pTh17 cells were selectively activated by adherent-invasive Escherichia coli [AIEC], but not by a commensal/probiotic E. coli strain. AIEC induced high levels of IL-23 and RANTES from dendritic cells [DC]. Intestinal CCR5+Th1/17 cells responded instead to cytomegalovirus and were reduced in ulcerative colitis [UC], suggesting an unexpected protective role. In conclusion, we identified an IL-23-inducible subset of human intestinal Th17 cells. pTh17 cells produced high levels of pro-inflammatory cytokines, were selectively associated with intestinal inflammation in CD, and responded to CD-associated AIEC, suggesting a key colitogenic role.

Outcomes after staged surgical treatment of children with ileocecal lesions and active extensive inflammation in Crohn’s disease

Introduction. Crohn’s disease is characterized with transmural lesion of the gastrointestinal tract which is frequently localized in the ileocecal region. Despite the achievements in medicamentous therapy, 15–45% of children have to be operated on within 5 years after the diagnosis is verified. Purpose. To substantiate the efficacy of two-stage surgical treatment of children with Crohn’s disease , ileocecal lesion and active extensive inflammation. Material and methods. A single-stage retrospective-prospective study included 43 children with ileocecal lesions and advanced colitis. Two-stage surgical treatment was performed. In the preoperative period, the following parameters were assessed: physical state, clinical activity, anemia and the level of hypoalbuminemia as well as inflammation markers, findings at endoscopy and MRI. Indications for surgical treatment were strictures in the ileocecal region, endoscopic and clinical activity and colon lesion and / or purulent-septic lesions in the perianal region. 39 (90.7 %) children had laparoscopically-assisted surgeries. 4 (9.3 %) children underwent conversions due to a pronounced infiltrative process in the abdominal cavity. Results. Lengths of hospitalization for children with stoma varied from 5 to 20 months (median 8 months). PCDAI index: in 25 (57.8 %) high activity, in 18 (41.2 %) moderate activity. After surgical intervention: 7 (16.2%) children had mild course, 36 children (p 0.05) SES-CD before surgery – all children had high endoscopic activity. In the postoperative period by Rutgeerts scale findings, there was a statistically significant positive dynamics (p = 0.011). Anthropometric parameters (HAZ p 0.05; BAZ p 0.001) and laboratory findings (p 0.001) were statistically significant for positive dynamics too.In the postoperative period: 5 (11.6 %) children developed ligature fistulas; 2 children (4.6 %) had narrowed intestinal anastomosis without passage disorders; 2 (4.6 %) children developed acute adhesive intestinal obstruction. In foreign and Russian publications, postoperative complications were reported in 6 % to 29 %. Conclusions. Crohn’s disease has led to chronic anemia, hypoalbuminemia, chronic bacterial inflammation, reduced physical growth and worsen quality of life. After the two-stage surgical treatment, the statistical analysis demonstrated a significant improvement in mass-growth, laboratory and endoscopic parameters.

Integrative multi-omics deciphers the spatial characteristics of host-gut microbiota interactions in Crohn’s disease

Dysregulated host-microbial interactions play critical roles in initiation and perpetuation of gut inflammation in Crohn's disease (CD). However, the spatial distribution and interaction network across the intestine and its accessory tissues are still elusive. Here, we profile the host proteins and tissue microbes in 540 samples from the intestinal mucosa, submucosa-muscularis-serosa, mesenteric adipose tissues, mesentery, and mesenteric lymph nodes of 30 CD patients and spatially decipher the host-microbial interactions. We observe aberrant antimicrobial immunity and metabolic processes across multi-tissues during CD and determine bacterial transmission along with altered microbial communities and ecological patterns. Moreover, we identify several candidate interaction pairs between host proteins and microbes associated with perpetuation of gut inflammation and bacterial transmigration across multi-tissues in CD. Signature alterations in host proteins (e.g., SAA2 and GOLM1) and microbes (e.g., Alistipes and Streptococcus) are further imprinted in serum and fecal samples as potential diagnostic biomarkers, thus providing a rationale for precision diagnosis.

The use of a multi-strain probiotic and high dietary vitamin D to ameliorate acute TNBS-induced colitis in mice

Inflammatory Bowel Diseases (IBD) either Crohn’s disease or Ulcerative colitis are debilitating disorders that affect the gastrointestinal tract with chronic inflammation. Patients with IBD are often characterized by having a change in the gut microbiome composition and decreased levels of vitamin D, which contribute to disease development. Because of this, the separate use of probiotics and vitamin D has gained attention as complementary treatments. However, the beneficial effects of combining these treatments to target colitis inflammation by modulating gut microbiome and immune cells are still unknown. Therefore, the objective of this research was to demonstrate the efficacy of probiotics and high dietary vitamin D to ameliorate colonic inflammation. We hypothesized that co-administration of probiotics and vitamin D will synergistically reduce colitis induced inflammation. For the methodology, male and female C57bl/6 mice were divided into 4 groups: Colitis (n=6), Colitis + Probiotic (n=6), Colitis +Vitamin D (n=6), Colitis + Probiotic + Vitamin D (n=6). Animals received 7 days of pretreatment with Vivomixx probiotic in drinking water, high vitamin D (5IU/g) in food, or both treatments combined. At day 7, animals were lightly anesthetized with ether and colitis induction was done by intracolonic administration of 0.1mL of 4mg trinitrobenzenesulfonic acid in 30% ethanol. Water, food, and body weight were monitored daily. Animals were sacrificed 3 days post colitis induction and colonic tissue was collected to assess colonic inflammation by macroscopic score, colon length, and myeloperoxidase activity (MPO). Results obtained indicate that animals had similar food and water consumption during the 7 days pretreatment of probiotic and vitamin D.After 48 hours of colitis induction, all animals lost an average of 15% of their weight. At day of sacrifice, colitis untreated animals continued to lose weight, while administration of probiotic and probiotic +Vitamin D significantly recovered body weight (7.55%, p<0.05 and 9.55%, p<0.01, respectively) compared to colitis untreated. Similarly, animals treated with probiotic (4.11, p=0.0017) and probiotic + Vitamin D (4.02, p=0.0012) had significantly decreased macroscopic damage score compared to colitis (10.9). Treatment with vitamin D alone did not improve weight loss or macroscopic score. In conclusion, results obtained indicate that probiotic administration may be responsible for colitis recovery by decreasing weight loss and colonic inflammation. Future studies will increase the number of animals to determine if synergistic effects occur between probiotic and vitamin D to ameliorate colitis by modulating the gut microbiome and increasing anti-inflammatory cytokines. Supported in part by 5R25GM082406 and 1T32GM144896 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Diverse but desolate landscape of gut microbial azoreductases: A rationale for idiopathic IBD drug response

ABSTRACT Prodrugs reliant on microbial activation are widely used but exhibit a range of efficacies that remain poorly understood. The anti-inflammatory compound 5-aminosalicylic acid (5-ASA), which is packaged in a variety of azo-linked prodrugs provided to most Ulcerative Colitis (UC) patients, shows confounding inter-individual variabilities in response. Such prodrugs must be activated by azo-bond reduction to form 5-ASA, a process that has been attributed to both enzymatic and non-enzymatic catalysis. Gut microbial azoreductases (AzoRs) are the first catalysts shown to activate azo-linked drugs and to metabolize toxic azo-chemicals. Here, we chart the scope of the structural and functional diversity of AzoRs in health and in patients with the inflammatory bowel diseases (IBDs) UC and Crohn’s Disease (CD). Using structural metagenomics, we define the landscape of gut microbial AzoRs in 413 healthy donor and 1059 IBD patient fecal samples. Firmicutes encode a significantly higher number of unique AzoRs compared to other phyla. However, structural and biochemical analyses of distinct AzoRs from the human microbiome reveal significant differences between prevalent orthologs in the processing of toxic azo-dyes, and their generally poor activation of IBD prodrugs. Furthermore, while individuals with IBD show higher abundances of AzoR-encoding gut microbial taxa than healthy controls, the overall abundance of AzoR-encoding microbes is markedly low in both disease and health. Together, these results establish that gut microbial AzoRs are functionally diverse but sparse in both health and disease, factors that may contribute to non-optimal processing of azo-linked prodrugs and idiopathic IBD drug responses.

Brunner gland inflammation in Crohn's disease and Celiac disease: Overlapping inflammatory patterns suggest a possible link

Similar to celiac disease, inflammatory bowel disease frequently manifests in the duodenum. Histopathologic studies focused on mucosal alterations with little attention to submucosal Brunner glands. Recently, several studies have demonstrated overlapping features between Crohn's disease and celiac disease suggesting a putative link. However, histopathologic studies evaluating this possible link are limited, and those that are focused on Brunner glands are lacking. The present study aims to explore whether Crohn's disease and celiac disease display shared or overlapping inflammatory changes in Brunner glands. We performed a retrospective review study over 17-years retrieving duodenal biopsy specimens containing Brunner gland lobules in patients with Crohn's disease, celiac disease, and ulcerative colitis. We found 10 out of 126 duodenal biopsies (8 %) in patients with Crohn's disease and 6 out of 134 (4.5 %) duodenal biopsies in patients with celiac disease sharing inflammatory patterns in duodenal Brunner gland lobules. Both diseases showed interstitial intralobular and interlobular mixed chronic inflammation with variable fibrosis. Focally enhanced active inflammation of Brunner gland lobules was more characteristic of Crohn's disease. Intralobular epithelioid granulomas and multinucleated giant cells were specific to Crohn's disease. Ulcerative colitis patients did not show similar features. The interstitial focally enhanced chronic inflammatory pattern was significantly (p < 0.05) associated with both diseases, while the other inflammatory patterns were not (p > 0.05). This overlapping inflammatory pattern in Brunner glands in patients with Crohn's disease and celiac disease is supportive of the previously reported link between the two diseases. Pathologists should pay more attention to Brunner glands when evaluating duodenal biopsies. Further studies are warranted to validate these observations and their relevance in the pathogenesis of autoinflammatory gastrointestinal diseases.

Validation of the simplified magnetic resonance index of activity by using DWI without gadolinium enhancement to evaluate bowel inflammation in Crohn's disease.

To validate the modified simplified magnetic resonance index of activity (sMARIA) score using DWI on non-contrast magnetic resonance enterography (MRE) to evaluate active inflammation in patients with Crohn's disease (CD), compared to the original sMARIA scoring system, with and without contrast enhancement. This retrospective study included 275 bowel segments from 55 CD patients who underwent ileocolonoscopy and MRE within a 2-week period. Two blinded radiologists evaluated original sMARIA on both conventional MRE (CE-sMARIA) and non-contrast MRE (T2-sMARIA). Modified sMARIA was then evaluated using non-contrast MRE, replacing ulcerations with DWI grades. Three scoring systems were compared for diagnostic accuracy of active inflammation, correlation with simple endoscopic score (SES)-CD, and interobserver reproducibility. The AUC of modified sMARIA for detecting active inflammation (0.863, 95% confidence interval [0.803-0.923]) was significantly higher than T2-sMARIA (0.827 [0.773-0.881], p = 0.017), and comparable to CE-sMARIA (0.908 [0.857-0.959], p = 0.122). CE-sMARIA, T2-sMARIA, and modified sMARIA all showed moderate correlation with SES-CD (r = 0.795, 0.722, and 0.777, respectively). Interobserver reproducibility of diffusion restriction (κ, 0.686 [0.602-0.770]) was significantly better than ulcers on conventional MRE (κ, 0.382 [0.212-0.552]; p = 0.001) and T2-weighted image (κ, 0.312 [0.034-0.590]; p = 0.012). Modified sMARIA using DWI can improve the diagnostic performance of sMARIA on non-contrast MRE, showing comparable performance to sMARIA using contrast-enhanced MRE. • DWI can improve the diagnostic performance of non-contrast magnetic resonance enterography (MRE) for assessing active inflammation in patients with Crohn's disease. • Modified simplified magnetic resonance index of activity (sMARIA) using DWI grades in place of ulcers showed comparable diagnostic performance to sMARIA using conventional MRE with contrast-enhanced sequences.

Dysplasies conventionnelles et non conventionnelles compliquant les maladies inflammatoires chroniques de l’intestin

Compared to the general population, patients with inflammatory bowel disease (IBD), both ulcerative colitis (UC) or Crohn's disease (CD), are at increased risk of developing some cancers, particularly colorectal cancers (CRC). CRCs, the vast majority of which are adenocarcinomas, develop from a precancerous lesion called dysplasia (or intraepithelial neoplasia) via an inflammation-dysplasia-adenocarcinoma sequence. The advancements of new endoscopic techniques, including visualisation and resection techniques, has led to a reclassification of dysplasia lesions into visible and invisible lesions and their therapeutic management, with a more conservative approach to the colorectal setting. In addition, besides conventional dysplasia, of intestinal phenotype, classically described in IBD, non-conventional dysplasias (as opposed to conventional dysplasia of intestinal phenotype) are now described, including at least seven subtypes. Recognition of these unconventional subtypes, which are still poorly known from pathologists, is becoming crucial, as some of these subtypes appear to be at high risk of developing advanced neoplasia (i.e. high-grade dysplasia or CRC). This review briefly describes the macroscopic features of dysplastic lesions in IBD, as well as their therapeutic management, followed by the clinicopathological features of these dysplastic lesions, with particular emphasis on the new subtypes of unconventional dysplasia, both from a morphological and molecular point of view.

A205 EVALUATING THE ASSOCIATION BETWEEN PERIPHERAL BLOOD EOSINOPHILS AND DRUG RESPONSE IN CROHN'S DISEASE: CONTINUING ANALYSIS

Abstract Background Th2 cytokines, IL-5 and IL-13 enhance peripheral and mucosal eosinophil survival, recruitment and degranulation, facilitating inflammation in Crohn's Disease. In a preliminary analysis, peripheral eosinophilia (PBE) is seen to have an association with rates of steroid response and anti-TNF response in CD patients. Participants with high PBE (&amp;gt; 200 cells/μL) appear to be more steroid-responsive but less responsive to Th1-targeting anti-TNF therapies. We hypothesize the pattern of PBE at CD diagnosis can help identify distinct subsets within a larger CD population and correlate with response to treatments such as prednisone or anti-TNFs. Purpose We aim to evaluate the pattern of PBE of CD patients at time of diagnosis (prior to drug exposure) and with each subsequent treatment; and if baseline PBE or any changes seen with drug exposures are predictive of treatment response. Method A retrospective cohort study is ongoing with CD patients exposed to glucocorticoids and an anti-TNF seen at 3 hospitals affiliated with University of Western Ontario. Patients were identified using administrative databases and reviewed for biochemical data (complete blood count) and disease activity (Harvey Bradshaw Index) at baseline, before and after each drug exposure. Participants were classified as having high PBE (eosinophils&amp;gt;200 cells/μL) versus low PBE (eosinophils &amp;lt;200 cells/μL). To date, 350 patients have been screened. Subgroup analyses of PBE &amp;gt; 300 cells/μL, and differences between female and male patients will be carried out. Result(s) 46 of 200 CD patients are included in the continuing analysis with a mean age of 45 years. 26 had PBE &amp;gt;200 cells/μL at baseline and 20 did not. The median number therapies used was 4 (IQR=0.75). All received glucocorticoids followed by an anti-TNF. There was no difference in the occurrence of hospitalization or surgery between the two groups. Overall 50% participants with high PBE &amp;gt;200 and &amp;gt;300 cells/μL had clinical response to glucocorticoid exposure, seen as a 3-point decrease in HBI compared to 45%, 47% in the low PBE cohort (n=13/26 vs. n=9/20 p=0.77; n=6/12 vs. n=16/34 p=1.0 respectively). With subsequent anti-TNF exposure, PBE rebounded in 7 participants. 36% patients in the high PBE group required anti-TNF dose escalation versus 24% in the low PBE group (n=9/25 vs. n=5/21, p=0.52). The proportion of patients with anti-TNF discontinuation was similar in both groups (high PBE 19.2%, n=5/26 vs. low PBE 15%, n=3/20, p=1.0). Men had higher steroid response rates compared to women in both high and low PBE groups (n=6/8 vs. n=8/18 p=0.21; n=4/9 vs. 4/11 p=1.0 respectively). Conclusion(s) Peripheral eosinophilia is seen in varying degrees in CD patients. Participants with high PBE are more steroid-responsive. High PBE patients overall were less responsive to anti-TNF therapies, requiring more dose-escalation and discontinued anti-TNF treatment. Completion of this study will help clarify the association between PBE in CD and treatment response. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

A164 IDENTIFYING THE MOST IMPORTANT PREDICTORS TO CORRELATE SERUM METABOLITES WITH MRE CHANGES IN PATIENTS WITH PEDIATRIC CROHN DISEASE

Abstract Background Endoscopy has been the gold standard for assessing activity in Pediatric Crohn disease (pCD); however, it is limited by its invasiveness and partial assessment of small intestine and transmural inflammation. To that end, the Pediatric Inflammatory Crohn's MRE Index (PICMI) is a valid, reliable, non-invasive, and responsive index that includes transmural inflammation when assessing disease activity. The pathogenesis of pCD remains poorly understood, but evidence suggests that endogenous metabolites produced in the intestinal tract might mediate pathogenesis. Despite the important applicability of metabolomics in increasing the understanding of pCD, there has been limited research on this topic. Purpose Serum metabolomic profiles are linked to disease activity in pediatric Crohn disease. Method ImageKids is a multicenter, prospective, observational cohort study, designed to develop PICMI for pCD. The study was conducted over 18 months with paired serum specimens collected at study initiation and completion for 56 pCD patients. Due to the long time between the visits and the fact that during the study variables that highly affect serum metabolites were not controlled, we considered each patient visit as an individual measure point. Metabolites were identified using a quantitative metabolomics approach through The Metabolomics Innovation Centre (TMIC; University of Alberta). Disease activity was determined by the cutoff values in the total PICMI score of each patient. The most relevant serum metabolites were identified by medium-level and high-level variable selection analysis. Pearson correlation and hypothesis testing were used to select important metabolites. Decision trees, regularization techniques, and support vector machines were used to assess explicit importance of metabolites in disease activity. Result(s) This work provides a strategy to reduce a dimensional dataset from a metabolomic experiment. By medium-level selection analysis we were able to identify 117 statistical important metabolites for disease activity. The high-level selection analysis allowed to indicate the importance of the top 10 metabolites trough disease activity (defined by PICMI index). Results, also show that the evaluation of importance of metabolites through multivariate statistical models is dependent of the intrinsic variable selection model. Figure 1 reveals that Tryptophan ranked highest in the feature importance scoring. Histidine, Methylhistidine, Citric acid, Isoleucine, and Decanoylcarnitine also correlated well with disease severity. Image Conclusion(s) This work uses a unique approach of multivariate statistical analyses, to identify metabolites associated with pCD disease activity. Tryptophan has been previously identified as significantly altered in the blood of IBD patients compared to controls. Histidine is known to be involved in the mediation of oxidative stress, potentially influencing intestinal inflammation. These metabolites could serve as biomarkers and help define pCD pathogenesis. Disclosure of Interest None Declared

Clinicopathologic Spectrum of Renal Lesions Following Anti-TNF- α Inhibitor Therapy: A Single Center Experience.

Anti-tumor necrosis factor (TNF)-alpha inhibitors, as biological agents, are used in autoimmune inflammatory states, rheumatoid arthritis (RA), psoriatic arthritis (PA), and Crohn's disease. They can induce autoimmune serologic responses and clinical disorders including systemic vasculitis and lupus-like diseases, affecting the kidney. Retrospective analysis of clinicopathologic features of kidney disease following anti-TNF alpha therapy (treatment group) from our renal biopsy files from 2000-2018 is conducted and compared with 106 cases without therapy (control group). Forty-eight patients using anti-TNF-alpha agents had renal biopsies, RA in 30, PA in 6, Crohn's disease 6, RA and PA 1, RA and Crohn's disease 1, and others 4. 20 received etanercept, 15 adalimumab, 8 infliximab and 5 had 2 forms of agents manifesting new onset nephritic syndrome or CKD, 17 with acute kidney injury and 16 nephrotic syndrome, with recent ANCA and/or lupus serology. The renal lesions were crescentic glomerulonephritis in 8, 5 pauci-immune type and 5 ANCA+. Lupus or lupus-like nephritis seen in 6: ISN/RPS 2018 class II-2, class V-2, class III+V-1, class IV+V-1, 3 with concurrent fibrillary GN, scleroderma/TMA and amyloidosis. Renal lesions unrelated to anti-TNF-alpha therapy or underlying autoimmune disease in 23 (eg diabetic nephropathy, interstitial nephritis, acute tubular injury, infection-related GN), IgA nephropathy, renal sarcoidosis and AA amyloidosis were noted in 5 cases. Thrombotic microangiopathy was recognized in 5 cases, 1 associated with scleroderma and 1 antiphospholipid antibodies, and 2 nephrotic syndrome secondary to podocytopathy. The control group was similar with higher immune mediated GN, interstitial nephritis and amyloidosis. The renal lesions during anti-TNF-alpha therapy have an autoimmune basis such as ANCA, lupus or lupus-like disease, correlated with new onset serology, while others were similar to those observed in the control group. Renal biopsy findings integrated with clinical features and therapy can identify the underlying pathophysiologic process for appropriate management.

P017 Fecal wash host transcriptomics identifies inflammation throughout the colon and terminal ileum

Abstract Background Non-invasive modalities for assessing active endoscopic and histological inflammation in Crohn’s disease and Ulcerative Colitis patients are critically needed. Fecal wash host transcriptomics has been shown to be a robust classifier of endoscopic and histological inflammation in inflammatory bowel disease (IBD) patients with distal colitis. Whether such fecal washes can inform on inflammatory processes occurring in more proximal intestinal segments is currently unknown. Methods Crohn's disease and Ulcerative Colitis patients as well as healthy controls were prospectively enrolled. Host transcriptomes of biopsies and fecal washes obtained during colonoscopy at predefined locations throughout the colon and terminal ileum were analyzed and associated with same time-point clinical, endoscopic and histological parameters. Results 59 IBD patients and 50 controls were prospectively enrolled. Biospies and fecal washes from the distal, proximal colon and terminal ileum were compared. We find that host transcriptomics of distal fecal washes robustly classify histological inflammation in ileal and proximal colonic Crohn’s disease, even without distal colonic involvement. Receiver operating characteristic (ROC) curve analysis demonstrated significantly higher classification power based on the fecal wash transcriptomics compared to biopsies: Area Under the Curve, AUC=0.94+-0.07 for UC distal fecal washes and AUC=0.94+-0.09 for distal fecal washes of CD patients without distal colonic involvement, as compared to all distal biopsies AUC= 0.82+-0.20. We further demonstrate that fecal washes consist of modules of co-expressed immune, stromal and epithelial genes. Fecal wash expression of gene modules previously associated with lack of response to biological therapies correlates with disease severity. Figure 1 - Host transcriptomics of fecal washes from different intestinal segments captures information that is distinct from same – segment biopsy transcriptomics. A) Experimental layout. B) Clustergram of transcriptomes of biopsies (purple) and fecal washes (yellow). C) Principal component analysis (PCA) of biopsies (purple) and fecal washes (yellow). Black circles highlight inflamed samples. D) Spearman correlations between the transcriptomes of pairs of either biopsies or fecal washes that are both annotated as inflamed and mixed pairs (one annotated as inflamed and the other not). (A) Created with BioRender.com. TI – terminal ileum, P – proximal colon, D – distal colon. Conclusion Our study establishes the power of colonic fecal washes for identifying pathological processes throughout the ileal-colonic axis.

P036 Analysis of intestinal tissue from newly diagnosed patients with inflammatory bowel disease reveals distinct proteomic profiles

Abstract Background Inflammatory bowel disease (IBD) is a complex multi-factorial disease characterized by chronic inflammation of the gastrointestinal tract. Despite significant efforts to understand the pathogenetic mechanisms of IBD, the elucidation of its etiopathology and progression is far from fully understood. The direct analysis of the intestinal tissue from the endoscopy which leads to IBD diagnosis (before starting any treatment) would be the ideal sample to elucidate IBD pathogenesis. Methods High-throughput mass-spectrometry-based quantitative proteomic analysis was performed using formalin-fixed paraffin-embedded human intestinal samples from newly diagnosed patients to elucidate the potential mechanisms responsible for gut inflammation in Crohn′s disease (CD) and ulcerative colitis (UC). For this purpose, 192 formalin-fixed paraffin-embedded samples from 40 active UC patients, 67 active CD patients and 46 normal biopsies from healthy controls (HC) were analyzed (Figure 1). Proteins with p-value &amp;lt; 0.05 were considered as significantly dysregulated. Moreover, we used Ingenuity Pathway Analysis (IPA) to analyze the pathways and functions in different locations of the gut (ileum or left colon) that could be related to IBD pathogenesis. Results A total of 2,903 proteins were identified, of which 1,010 were differentially expressed between left colon from CD patients and HC. 1,242 proteins were differentially expressed between left colon from UC patients and HC, and 952 differential proteins discriminated between left colon from CD and UC patients. In the comparative study of ileum biopsies from Crohn’s disease patients and healthy controls, 956 proteins were differentially expressed (Figure 2). IPA revealed multiple canonical pathways, including EIF2 signaling, regulation of eIF4 and serine/threonine kinase P7056K signaling, mitochondrial dysfunction, and oxidative phosphorylation altered in ileum biopsies from CD patients compared to HC (Figure 3). Regarding the proteomic study in left colon samples, the main canonical pathways enrichment in the comparison of UC and CD with HC were the following: neutrophil extracellular trap signaling pathways, fatty acid oxidation, sirtuin signaling pathway, tRNA charging, and mitochondrial dysfunction (Figure 4). Conclusion The proteomic results revealed dysregulated proteins and pathways in ileum and left colon biopsies from patients with active CD and UC compared to HC that may unravel key mechanisms contributing to the pathogenesis of these diseases. The results of the study serve as a starting point for hypotheses to understand the pathogenesis and search for therapeutic targets.

P013 Role of IL-36RA mutations in Crohn’s disease

Abstract Background The interleukin 36 (IL-36) family consists of three agonists (IL-36α, IL-36β, IL-36γ), that activate the NF-κB pathway and lead to the production of pro-inflammatory cytokines and the natural antagonist (IL-36RA), which inhibits IL-36 signaling. While it is known that IL-36 signaling is important in the skin, it has been only recently reported that IL-36 might play an important role in maintaining gut homeostasis and in the development of fibrosis (Scheibe et al., 2019). Here, we aim to understand how IL-36RA mutations contribute to development and maintenance of intestinal inflammation in Crohn’s disease. Methods By whole-exome sequencing (WES) and subsequently targeted Sanger sequencing we identified a Crohn’s disease (CD) patient with a heterozygous missense mutation in IL-36RA (p.Ser113Leu). To understand how the mutation affects immune cells composition and function, we characterized peripheral blood mononuclear cells (PBMCs) of the patient by mass cytometry and measured cytokine levels in the serum by ELISA. In an available WES dataset of 177 CD patients, 47 ulcerative colitis (UC) patients and 34 healthy donors (HD), we searched for additional patients with IL-36RA mutations. Finally, we overexpressed the identified IL-36RA mutations in HEK cells and produced mutated recombinant proteins to study the effect of the mutations on protein expression and function. Results Our IL-36RA mutation-carrying patient presented with a severe course of Crohn’s disease and consecutive of fibrosis, which was resistant to all commonly used treatment options. In the patient, we detected increased levels of IL-36RA, IL-18 and IL-23 in the serum and an increased frequency of TH17 cells in the blood. These findings could hint towards an over-activation of the IL-36 signaling pathway in the IL-36RA mutated patient. In the available WES data, we identified two more CD patients with IL-36RA mutations (p.Leu133Ile, p.Pro76Leu), indicating that IL-36RA mutations are enriched in CD patients. By overexpressing the three identified mutations in HEK cells, we could demonstrate that two mutations (p.Ser113Leu and p.Pro76Leu) lead to a reduced protein expression. Also, our current data shows that the p.Ser113Leu mutant has a reduced capacity to antagonize IL-36 stimulation. However, further testing is required for the two other IL-36RA mutants. Conclusion Our data suggests that IL-36RA mutations are enriched in Crohn’s disease patients and should be considered as a possible cause for therapy-refractory and fibrotic Crohn’s disease.

The Role of the Microbiome in the Etiology of Inflammatory Bowel Diseases.

Inflammatory bowel diseases (IBDs) result from dysregulated immune responses to environmental and microbial triggers in genetically susceptible hosts. Many clinical observations and animal studies support the role of the microbiome in the pathogenesis of IBD. Restoration of the fecal stream leads to postoperative Crohn's recurrence, while diversion can treat active inflammation. Antibiotics can be effective in prevention of postoperative Crohn's recurrence and in pouch inflammation. Several gene mutations associated with Crohn's risk lead to functional changes in microbial sensing and handling. However, the evidence linking the microbiome to the IBD is largely correlative, given the difficulty in studying the microbiome before disease occurs. Attempts to modify the microbial triggers of inflammation have had modest success to date. Exclusive enteral nutrition can treat Crohn's inflammation though no whole food diet to date has been shown to treat inflammation. Manipulation of the microbiome through fecal microbiota transplant and probiotics have had limited success. Further focus on early changes in the microbiome and functional consequences of microbial changes through the study of metabolomics are needed to help advance the field.

Distal Fecal Wash Host Transcriptomics Identifies Inflammation Throughout the Colon and Terminal Ileum

Noninvasive modalities for assessing active endoscopic and histologic inflammation in Crohn's disease and ulcerative colitis patients are critically needed. Fecal wash host shed-cell transcriptomics has been shown to be a robust classifier of endoscopic and histologic inflammation in inflammatory bowel disease patients with distal colitis. Whether such fecal washes can inform on inflammatory processes occurring in more proximal intestinal segments is currently unknown. Fifty-nine inflammatory bowel disease patients and 50 controls were prospectively enrolled. Biopsy specimens and fecal washes from the distal colon, proximal colon, and terminal ileum were compared. Host transcriptomics were performed on the biopsy specimens and fecal washes obtained during colonoscopy at predefined locations throughout the colon and terminal ileum and results were associated with concurrent clinical, endoscopic, and histologic parameters. We found that host transcriptomics of distal fecal washes robustly classify histologic inflammation in ileal and proximal colonic Crohn's disease, even without distal colonic involvement (area under the receiver operating characteristic curve, 0.94 ± 0.09). We further found that fecal washes consist of modules of co-expressed genes of immune, stromal, and epithelial origin that are indicative of endoscopic disease severity. Fecal wash host transcriptomics also captures expression of gene modules previously associated with a lack of response to biological therapies. Our study establishes the accuracy of distal colonic fecal washes for identifying and scoring inflammatory processes throughout the entire ileal-colonic axis.

SJLA_2024_A4: Surgical Outcomes and Stoma-related Complications in Inflammatory Bowel Disease in Saudi Arabia: A Retrospective Study

Background: The prevalence of inflammatory bowel diseases (IBD), Crohn’s (C), and ulcerative colitis (UC) has increased in Saudi Arabia during the past decade. Even though medical treatment is first-line therapy, most patients require surgery during the course of the disease. Stoma-creation complications in IBD are underreported in the literature of the Middle East, especially in Saudi Arabia. Objectives: The objective of the study was to report the postoperative, stoma and peristomal complications following stoma creation in (C) versus UC. Design: The study design was a retrospective cohort study. Settings: The study was conducted at tertiary care center. Patients and Methods: Patients with IBD who underwent stoma creation for either UC or CD between August 2015 and July 2020 were included. The diseases were compared to assess their characteristics and association with postoperative, stoma, and peristomal complications. All complications were reported over a 90-day duration from the surgery. Patients younger than 14 years of age were excluded. Main Outcome Measures: Postoperative complications, stoma, and peristomal complications in IBD patients who underwent stoma creation. Sample Size: Fifty. Results: Of 50 IBD patients underwent stoma creation, 32 patients (64%) were diagnosed with CD and 18 patients (36%) with UC. Most of the procedures in both groups were laparoscopic and elective. Low body mass index and serum albumin were more prevalent in the CD group. Postoperative complications were higher in the CD patients compared to the UC patients (CD 40.6% vs. UC 11.1%, P = 0.028) with the most common complication being abdominal collection(a). Stoma complications were comparable between the two groups (UC 16.7% vs. CD 15.6%). However, peristomal complications were higher clinically in UC patients in comparison with the CD patients (UC 61.1% vs. CD 37.5% P = 0.095) with the most common complication being skin excoriation (UC 44.4% vs. CD 37.5%). Conclusion: CD has significantly higher postoperative complications compared to UC. Peristomal complications were high in both groups and had a negative impact on quality of life. Therefore, comprehensive stoma education and regular outpatient follow-ups are recommended to improve the overall outcomes. Limitations: This study was retrospective and conducted in one academic institution with a small sample size.

DWI ratios: New indexes for Crohn's disease activity at magnetic resonance enterography?

The aim of the study was to provide radiologists and clinicians a rapid tool for assessment of intestinal inflammation in Crohn's disease (CD) patients through quantification of diffusion-weighted imaging (DWI) signal intensity while performing magnetic resonance enterography (MRE). A monocentric retrospective study was conducted between September 2018 and July 2021 on CD patients who underwent MRE. Two radiologists measured signalintensity on DWI scans at the highest b-value (800s/mm2) within pathologicintestinal walls, lymph nodes, spleen and psoas muscle and calculated the relative ratios. Spearman, Mann-Whitney and Jonckheere-Terpstra tests were applied for estimating correlation among ratios, significant differences between the two patient groups and determining the trend in relation to endoscopic classes. Wilcoxon's and Cronbach's alpha tests were employed for comparison of DWI measurements and ratios between the two observers. Fifty-nine patients were enrolled in the study. In the non-surgical group, correlation has been found among Simple Endoscopic Score for Crohn's Disease (SES-CD) classes and the different ratios: bowel/spleen (p = 0.034), bowel/psoas (p = 0.008) and bowel/lymph node (p = 0.010). Within the surgical group, positive correlation was found only between bowel/lymph node ratio and bowel/psoas ratio (p = 0.014). The J-T test demonstrated an increasing monotonic trend for bowel/psoas ratio and bowel/lymph node ratio and SES-CD classes. Inter-reader evaluation demonstrated no statistical differences for DWI measurements and high degree of concordance for the final ratios. DWI ratios correlate with endoscopic classes in non-surgical patients and have inter-observer reproducibility.

Serum Leucine-Rich α2 Glycoprotein: A Novel Biomarker for Transmural Inflammation in Crohn's Disease.

Leucine-rich alpha-2 glycoprotein (LRG) is a newly studied biomarker for inflammatory diseases. This study aimed to investigate whether LRG can be used for evaluating transmural activity in patients with Crohn's disease (CD). We performed magnetic resonance enterography (MRE) in 227 consecutive patients with CD from June 2020 to August 2021. We prospectively compared MRE findings with clinical and laboratory data including LRG. MRE was evaluated using 2 validated scoring systems, and transmural inflammation was defined as having a maximum simplified magnetic resonance index of activity (sMaRIA) score of ≥4 and a 5-point classification score of ≥9, respectively. The correlation between LRG and the total MRE score showed a positive correlation ( r = 0.576 for the sMaRIA score, P < 0.01, and r = 0.633 for the 5-point score, P < 0.01). Serum concentrations of LRG significantly increased as MRE scores increased ( P < 0.01). The area under the curve of LRG for a sMaRIA score of ≥4 and a 5-point score of ≥9 was 0.845 and 0.869, respectively, which was significantly higher than that of CDAI ( P < 0.01) or C-reactive protein ( P < 0.01). LRG levels of ≥14 μg/mL had a 67% sensitivity and 90% specificity for a sMaRIA score of ≥4 and a 73% sensitivity and 89% specificity for a 5-point score of ≥9. Patients with high LRG levels were also strongly associated with CD-related hospitalization, surgery, and clinical relapse compared with those with low LRG levels ( P < 0.01 for all). LRG is a highly accurate serum biomarker for detecting transmural activity in patients with CD. Results need to be validated in further multicenter studies.