Role of adherent and invasive Escherichia coli in Crohn's disease: lessons from the postoperative recurrence model.

OBJECTIVE: We used the postoperative recurrence model to better understand the role of adherent and invasive Escherichia coli (AIEC) bacteria in Crohn's disease (CD), taking advantage of a well-characterised postoperative cohort. DESIGN: From a prospective, multicentre cohort of operated patients with CD, AIEC identification was performed within the surgical specimen (M0) (N=181 patients) and the neoterminal ileum (n=119 patients/181) during colonoscopy performed 6 months after surgery (M6). Endoscopic postoperative recurrence was graded using Rutgeerts' index. The mucosa-associated microbiota was analysed by 16S sequencing at M0 and M6. Relative risks or ORs were adjusted on potential confounders. RESULTS: AIEC prevalence was twofold higher within the neoterminal ileum at M6 (30.3%) than within the surgical specimen (14.9%) (p<0.001). AIEC within the neoterminal ileum at M6 was associated with higher rate of early ileal lesions (i1) (41.6% vs 17.1%; aRR 3.49 (95% CI 1.01 to 12.04), p=0.048) or ileal lesions (i2b+i3) (38.2% vs 17.1%; aRR 3.45 (95% CI 1.06 to 11.30), p=0.040) compared with no lesion (i0). AIEC within the surgical specimen was predictive of higher risk of i2b-endoscopic postoperative recurrence (POR) (aOR 2.54 (95% CI 1.01 to 6.44), p=0.049) and severe endoscopic POR (aOR 3.36 (95% CI 1.25 to 9.06), p=0.017). While only 5.0% (6/119) of the patients were AIEC-positive at both M0 and M6, 43.7% (52/119), patients with history of positive test for AIEC (M0 or M6) had higher risk of ileal endoscopic POR (aOR 2.32 (95% CI 1.01 to 5.39), p=0.048)), i2b-endoscopic postoperative recurrence (aOR 2.41 (95% CI 1.01 to 5.74); p=0.048) and severe endoscopic postoperative (aOR=3.84 (95% CI 1.32 to 11.18), p=0.013). AIEC colonisation was associated with a specific microbiota signature including increased abundance of Ruminococcus gnavus. CONCLUSION: Based on the postoperative recurrence model, our data support the idea that AIEC are involved in the early steps of ileal CD. TRIAL REGISTRATION NUMBER: NCT03458195.

Autologous organoid co-culture model reveals T cell-driven epithelial cell death in Crohn's Disease.

Lympho-epithelial interactions between intestinal T resident memory cells (Trm) and the epithelium have been associated with inflammatory bowel disease (IBD) activity. We developed ex vivo autologous organoid-mucosal T cell cocultures to functionally assess lymphoepithelial interactions in Crohn's Disease (CD) patients compared to controls. We demonstrate the direct epithelial cell death induced by autologous mucosal T cells in CD patients but not in controls. These findings were positively correlated with T cell infiltration of the organoids. This potential was inhibited by limiting lympho-epithelial interactions through CD103 and NKG2D blocking antibodies. These data directly demonstrate for the first time the direct deleterious effect of mucosal T cells on the epithelium of CD patients. Such ex-vivo models are promising techniques to unravel the pathophysiology of these diseases and the potential mode of action of current and future therapies.

Identification of Gene Expression Profiles Associated with an Increased Risk of Post-Operative Recurrence in Crohn's Disease.

BACKGROUND AND AIMS: Ileocolonic resection is frequently needed in the course of Crohn's disease [CD] treatment and post-operative recurrence is extremely common. Our main objective was to analyse gene expression in the mucosa of CD patients at the time of surgery and at post-operative endoscopy, in order to identify predictors and mechanisms of early endoscopic recurrence. METHODS: We conducted transcriptome analyses on ileal mucosa samples collected from inflamed sections of the surgical specimens [n = 200], from ileal resection margins [n = 149] and in the neo-terminal ileum 6 months after surgery [n = 122]; these were compared with non-inflammatory bowel disease controls [n = 25]. The primary endpoint was post-operative endoscopic recurrence at 6 months. We applied regression models to identify gene signatures predicting endoscopic recurrence. RESULTS: Chronic inflammation was associated with strong expression of inflammatory genes [IL-6, IL-8, IL-1B] and decreased expression of genes involved in metabolic processes, but with a high inter-individual heterogeneity. Gene signatures associated with early endoscopic recurrence were mainly characterized by upregulation of TNFα, IFNγ, IL23A and IL17A. Pathway analyses showed that upregulation of mitochondrial dysfunction within the inflamed sections and JAK/STAT at the ileal margin were predictive of post-operative recurrence. A combined model integrating these top pathway signatures improved the prediction of endoscopic recurrence [area under the curve of 0.79]. STAT3 phosphorylation at the surgical ileal margin was associated with severe recurrence at 6 months. CONCLUSION: We identified several biological pathways in surgical ileal mucosa specimens associated with an increased risk of disease recurrence. Integration of the JAK/STAT and mitochondrial dysfunction pathways in the clinical model improved the prediction of post-operative recurrence.

Postoperative Endoscopic Recurrence on the Neoterminal Ileum But Not on the Anastomosis Is Mainly Driving Long-Term Outcomes in Crohn's Disease.

INTRODUCTION: Early ileocolonoscopy within the first year after surgery is the gold standard to evaluate recurrence after ileocolonic resection for Crohn's disease (CD). The aim of the study was to evaluate the association between the presence and severity of anastomotic and ileal lesions at early postoperative ileocolonoscopy and long-term outcomes. METHODS: The REMIND group conducted a prospective multicenter study. Patients operated for ileal or ileocolonic CD were included. An ileocolonoscopy was performed 6 months after surgery. An endoscopic score describing separately the anastomotic and ileal lesions was built. Clinical relapse was defined by the CD-related symptoms, confirmed by imaging, endoscopy or therapeutic intensification; CD-related complications; or subsequent surgery. RESULTS: Among 225 included patients, long-term follow-up was available in 193 (median follow-up: 3.82 years [interquartile range: 2.56-5.41]). Median clinical recurrence-free survival was 47.6 months. Clinical recurrence-free survival was significantly shorter in patients with ileal lesions at early postoperative endoscopy whatever their severity was (I(1) or I(2,3,4)) as compared to patients without ileal lesions (I(0)) (I(0) vs I(2,3,4): P = 0.0003; I(0) vs I(1): P = 0.0008 and I(1) vs I(2,3,4): P = 0.43). Patients with exclusively ileal lesions (A(0)I(1,2,3,4)) had poorer clinical long-term outcomes than patients with exclusively anastomotic lesions (A(1,2,3)I(0)) (P = 0.009). DISCUSSION: A score describing separately the anastomotic and ileal lesions might be more appropriate to define postoperative endoscopic recurrence. Our data suggest that patients with ileal lesions, including mild ones (I(1)), could beneficiate from treatment step-up to improve long-term outcomes.

Association Between Microscopic Lesions at Ileal Resection Margin and Recurrence After Surgery in Patients With Crohn's Disease.

BACKGROUND AND AIMS: Different types of histologic lesions at the ileal margin, detected by histology, have been associated with increased rates of recurrence after ileocaecal surgery in patients with Crohn's disease (CD). We aimed to characterize histologic features of the ileal margin and to evaluate their association with disease recurrence. METHODS: We collected histologic data from 211 patients with ileal or ileocolonic CD who underwent ileocolonic resections at hospitals in France from September 2010 through December 2016. Ileal margins were analyzed. Early endoscopic recurrence was defined by a Rutgeerts score of i2 or more, 6 months after surgery. We also collected data from 10 adults with healthy ileum who underwent ileocecal resection for colonic tumors (controls). Clinical relapse was defined by CD-related symptoms confirmed by imaging, endoscopy, therapy intensification, CD-related complication, or subsequent surgery. RESULTS: Six months after surgery, 49% of patients had endoscopic recurrence; 5 years after surgery, 57% of patients had clinical relapse. Ileal margins were macroscopically affected in 20.9% of patients. CD transmural lesions at the margin (defined by mucosal ulceration or cryptitis, submucosal fibrosis and lymphoplasmacytic infiltrate of the subserosa) were observed in 13.6% of patients. Endoscopic recurrence was observed in 75% of patients with CD transmural lesions vs 46% of patients without (P =.005). In multivariate analysis, CD transmural lesions at the margin were independently associated with early endoscopic recurrence (OR, 3.83; 95% CI, 1.47-11.05; P =.008) and clinical recurrence (OR 2.04; 95% CI, 1.09-3.99; P =.026). CONCLUSION: In patients with CD, transmural lesions at the ileal margin were associated with an increased risk of post-operative recurrence. Histologic features of the ileal margin should be included in making decisions about post-operative therapy.

Prevalence of Yersinia Species in the Ileum of Crohn's Disease Patients and Controls.

Yersinia are common contaminants of food products, but their prevalence in the human gut is poorly documented. Yersinia have been implicated in Crohn's Disease (CD, an inflammatory bowel disease) however their role in CD is controversial. We performed highly sensitive PCR assays of specific sequences for the gyrB gene of Y. aldovae, Y. bercovieri, Y. enterocolitica, Y. intermedia, Y. mollaretii and the inv gene of Y. pseudotuberculosis. We analyzed a total of 470 ileal samples taken from 338 participants (262 CD patients and 76 controls) belonging to three independent cohorts. All patients and controls were phenotyped and genotyped for the main CD susceptibility variants: NOD2, ATG16L1, and IRGM. Yersinia were found in 7.7% of ileal samples (respectively 7.9 and 7.6% in controls and CD patients) corresponding to 10% of participants (respectively 11.8 and 9.5% in controls and CD patients). Y. enterocolitica, Y. pseudotuberculosis and Y. intermedia were the most frequently identified species. The bacteria were more frequent in resected specimens, lymph nodes and Peyer's patches. Yersinia were no more likely to be detected in CD tissues than tissues from inflammatory and non-inflammatory controls. CD patients treated with immunosuppressants were less likely to be Yersinia carriers. In conclusion, this work shows that Yersinia species are frequently found at low levels in the human ileum in health and disease. The role of Yersinia species in this ecosystem should now be explored.

Predicting sensorimotor and memory deficits after neonatal ischemic stroke with reperfusion in the rat.

Among experimental models of perinatal ischemic stroke, Renolleau's model mimics selected types of stroke at birth, including ischemia and reperfusion. However, its behavioural consequences on development have been poorly described. Here, ischemia-reperfusion was performed in 7-day-old Wistar rats. Between the ages of 9 and 40 days, sensorimotor and memory functions were assessed. The infarcted area was analysed by immunohistochemistry at 40 days of age. The remaining lesion was in the parietal cortex, in the form of a cone-shaped area. This area contained glial cells but neither neurons nor macrophages. Transient focal neonatal ischemia led to sensorimotor alterations in early adulthood, such as postural asymmetry, motor coordination and somatosensory deficits, and hyperactivity, as well as cognitive impairments, such as spatial reference memory deficits. Based on these results, we propose here a selection of behavioural tests that should constitute meaningful tools for assessing sensory and cognitive functions after experimental neonatal ischemic stroke.