Introduction

Crohn’s disease (CD), as a type of inflammatory bowel disease (IBD), is characterized by chronic inflammation in the intestinal tract and its incidence is rising globally. The factors involved in causing or triggering Crohn’s disease (CD) have yet to be confirmed. We recently demonstrated that the intestinal microbiome composition is associated with the risk of CD development; however, its potential causal effect remains unknown. Our study investigated whether stool microbiome might contribute to or trigger dysregulated immune response by transplanting stool into germ-free mice (GFM).

Aims & Methods

Fecal samples were collected from 12 discordant pairs of siblings (one who did not develop CD referred to as Healthy Matched Control (HMC) and another who subsequently developed CD, referred to as pre-CD). These subjects were recruited as part of the Crohn's and Colitis Canada Genetic, Environmental, Microbial Project (CCC-GEM) project, a cohort of prospectively followed healthy first-degree relatives. The stool was transplanted into RAG1-/- GFM before T-cell transfer-induced colitis (3 transplanted mice per donor). Body weight was monitored for 6 weeks after T-cell transfer. Fecal Lipocalin-2 (LCN-2) was measured by ELISA to assess gut inflammation. Intestinal tissue damage was assessed by a validated histology scoring. Pro-inflammatory cytokine gene profiles of intestinal tissue were measured by qPCR. The feces of colitic mice were collected after 6 weeks of T-cell transfer and used to investigate metabolic profile measured by UHPLC-MS/MS.

Results

At week 2 after T-cell transfer, mouse recipients of pre-CD stool experienced greater weight loss than mice receiving stool from HMC (p=0.004). LCN-2 of pre-CD mice was significantly higher after T-cell transfer at week 3. Intriguingly, pre-CD stool recipient mice had a higher histological damage score in the ileum (p=0.031). Mice receiving pre-CD stool had increased expression of selected pro-inflammatory cytokine genes in the ileum including Tnfα, Il-1β, Ifnγ, Il-10 and Tgfβ compared to mice that received HMC stool. Colonic tissue showed significant increases in TNFα and Tgfβ in the mice recipient of the pre-CD stool. Moreover, pre-CD stool led to significant changes in 40 fecal metabolites compared to HMC microbiome (0.01<p≤0.05). Spearman correlation between certain metabolites and colitis markers in mouse was observed. Fecal metabolomics in humans revealed two shared metabolic pathways associated with future onset of CD and murine inflammatory markers. Notably, there was a positive correlation between sphingolipids in humans and mice that was associated with increased colitis in mice. Sphingolipid metabolites also demonstrated positive correlation with mouse colitis marker and human CD subclinical markers.

Conclusion

These results showed that transplanted pre-CD stool worsened T cell transfer colitis in mice compared to HMC stool. This suggests that stool microbiome of individuals with CD is functionally altered years before diagnosis, exhibiting greater inflammatory potential when transferred to susceptible mice. Modulating pre-CD microbiome composition and/or function could lead to novel methods of CD prevention.

Introduction

Post-operative recurrence (POR) affects a substantial proportion of Crohn's disease (CD) patients following intestinal resection. While ileocolonoscopy remains the gold standard for detecting recurrence, its invasive nature and patient burden have spurred interest in non-invasive monitoring approaches. This study evaluates the performance of faecal calprotectin (FC) and cross-sectional imaging at different timepoints in predicting endoscopic recurrence in postoperative CD patients.

Aims & Methods

In this multicenter retrospective cohort of 895 CD patients who underwent ileocecal resection, we analyzed the diagnostic accuracy of FC measurements at 3, 6-12, and 18-24 months postoperatively for predicting endoscopic recurrence (Rutgeerts score ≥i2 or SES-CD ≥3). Additionally, we assessed the concordance between intestinal ultrasound (IUS) and magnetic resonance imagings (MRI) and endoscopic findings at both 6-12- and 18-24-months using kappa statistics.

Results

FC demonstrated modest discriminatory ability at 3 months (AUC 0.642, 95% CI: 0.530-0.753) and 6-12 months (AUC 0.653, 95% CI: 0.593-0.713), with improved performance at 18-24 months (AUC 0.676, 95% CI: 0.608-0.744). The optimal cutoff values for FC (47.5 μg/g at 3 and 6-12 months; 80.0 μg/g at 18-24 months) were substantially lower than standard thresholds (150-250 μg/g) used in non-operated patients.
At 6-12 months, radiological and endoscopic assessments showed moderate agreement (κ=0.426, p<0.001) with 63.2% concordance. At 18-24 months, IUS demonstrated superior agreement with endoscopic findings (κ=0.531, p<0.001; sensitivity 83.8%, specificity 72.7%) compared to MRI (κ=0.324, p<0.001). Notably, radiological remission at 18-24 months was identified as a significant protective factor against surgical recurrence (OR 0.356, 95% CI: 0.179-0.705, p=0.003).

Table I: Concordance between endoscopic and radiologic findings (IUS and MRI) for inflammation and remission at 18–24 months post-ileocecal resection. Abbreviations: IUS: Intestinal ultrasound, MRI: Magnetic resonance imaging.

Conclusion

Non-invasive monitoring with FC shows promise in postoperative CD surveillance, though diagnostic thresholds differ substantially from those established for non-operated patients. IUS demonstrates superior concordance with endoscopic findings compared to MRI, particularly at later timepoints. The protective role of radiological remission against surgical recurrence highlights the importance of transmural healing. Combining FC with radiological assessment, especially IUS, may provide a comprehensive, patient-friendly approach to monitoring postoperative CD, potentially reducing the need for invasive procedures in selected patients but further studies are needed in this direction.

Introduction

The BIOSTOP Trial is a prospective, multicenter, randomized, controlled, open-label study conducted in Norway to evaluate the two-year outcomes of tumor necrosis factor-alpha (anti-TNF) antibody withdrawal in patients with ulcerative colitis (UC) in sustained clinical and endoscopic remission. Prior non-randomized studies have suggested that approximately half of such patients maintain remission after anti-TNF discontinuation and that reintroduction of anti-TNF therapy is generally effective and safe in the event of relapse.

Aims & Methods

A total of 174 UC patients in confirmed clinical and endoscopic remission were enrolled across 19 gastroenterology centers between June 2017 and December 2020 and randomized 1:1 to either continue or discontinue anti-TNF therapy. Eligibility criteria included at least 12 months of first-line anti-TNF maintenance treatment, clinical remission, fecal calprotectin <200 µg/g, and endoscopic remission (Mayo endoscopic score 0 or 1). Two-year follow-up data were available for 172 patients (86 in each group). In 156 of the patients endoscopies were available for central reading (77 in the withdrawal group and 79 in the maintenance group). The primary endpoint was sustained endoscopic remission at two years.

Results

At two years, central reading of follow-up colonoscopies confirmed endoscopic remission in 64 of 77 patients (83%, 95% CI 71.8 – 93.1) in the anti-TNF withdrawal group, compared to 77 of 79 patients (96 %, 95 % CI 92.1 – 100.8) in the anti-TNF maintenance group. The non-inferiority primary endpoint of the study was thus not met. During the study period, 48% of patients in the withdrawal group and 88% in the maintenance group remained in sustained clinical and endoscopic remission without relapse. Among the 45 patients in the withdrawal group who experienced endoscopic confirmed relapse, 28 (62%) resumed anti-TNF therapy, with 26 achieving both clinical and endoscopic remission. Additionally, 10 of 13 patients with mild relapses achieved endoscopic remission with optimized non-biologic therapy. There were no difference in serious adverse events between the groups.

Conclusion

After two years, 83% of patients in the anti-TNF withdrawal group and 96% in the maintenance group were in clinical and endoscopic remission, including those who experienced flares and achieved new remission after reintroduction of anti-TNF or optimized non-biologic therapy. Nearly half of the patients maintained remission without anti-TNF, and the majority of relapses were effectively managed. These findings suggest that anti-TNF withdrawal is a safe option for selected UC patients in confirmed remission, provided they are monitored closely.
Trial Registration: ClinicalTrials.gov Identifier: NCT03011268; EudraCT Number: 2016-001409-18. Trial completion date: 31 January 2025.

Disclosure

No disclosures