DOP107 Real-time intestinal barrier assessment by endocytoscopy and confocal laser endomicroscopy uniquely correlates with multiple barrier protein expression and reflects the gut-brain axis
Authors: Iacucci M , Majumder S , Puga-Tejada M , Zammarchi I , Santacroce G , Capobianco I , Ditonno I , Morael J , Hayes B , Crotty R , Burke L , Aburto M R , Amamou A , Ghosh S 
Published: January 2025

Abstract

Background
The intestinal barrier is gaining recognition as a key indicator of mucosal healing in IBD. Nonetheless, its assessment remains challenging. This study evaluates advanced endoscopic tools for real-time gut barrier assessment, examining their correlation with automated epithelial and vascular barrier markers and exploring their potential to elucidate the gut-brain axis.

Methods
IBD patients undergoing endoscopic assessment or surveillance and healthy controls were included. The intestinal mucosa was assessed with advanced imaging, i.e. ultra-high magnification endocytoscopy (ECS) or confocal laser endomicroscopy (CLE), using newly developed scores for barrier evaluation.1,2 Barrier healing was defined as ECS ≤ 1 -ileum and colon- and CLE ≤ 4 -colon- or ≤ 3 -ileum-. Biopsies were collected from different bowel segments, including representative inflamed and non-inflamed areas. Epithelial and vascular barrier markers, including ZO-1, Claudin-2, E-cadherin, PV-1 and CD-31, were analysed through confocal microscopy, and their expression was automatically quantified using QuPath. The validated IBD disk, focusing on energy, sleep and emotional components, was employed to evaluate neuropsychological functional impairment and indirectly assess gut-brain interaction.3 A per-biopsy-based linear regression model was used for inferential analysis using R software.

Results
A cohort of 33 IBD patients (15 CD and 18 UC) and 2 healthy controls were recruited (65 biopsies; 3.8 X106 cells). 9/16 (56%) patients who underwent ECS in the colon and 6/9 (67%) in the ileum had ECS scores indicative of barrier healing. CLE assessment revealed features suggestive of barrier healing in 3/11 patients (27%) in the colon and 1/14 (7%) in the ileum. ECS and CLE sub- and total scores demonstrated unique correlation with epithelial and vascular barrier proteins. For the epithelial barrier, CLE total scores in colon and ileum and villi architecture at ECS significantly correlated with Claudin-2 mean expression (p&lt;0.01). Regarding the vascular barrier, a significant correlation was found between ECS-assessed vascular architecture in ileum and colon and PV-1 mean expression (p&lt;0.01). In contrast, CLE-assessed blood flow in the colon was significantly correlated with CD-31 expression (p=0.03). Interestingly, patients with higher levels of sleeping difficulties based on IBD disk showed higher Claudin-2 and lower E-cadherin expression, while those with altered CD-31 expression reported lower energy levels.

Conclusion
CLE and ECS may offer a unique ability for real-time assessment of barrier impairment in IBD, showing promises for targeting real-time barrier healing and unravelling the complexities of gut-brain axis.

References
1Iacucci M, Jeffery L, Acharjee A, et al. Computer-Aided Imaging Analysis of Probe-Based Confocal Laser Endomicroscopy With Molecular Labeling and Gene Expression Identifies Markers of Response to Biological Therapy in IBD Patients: The Endo-Omics Study. Inflamm Bowel Dis. 2023;29(9):1409-1420. doi:10.1093/ibd/izac233
2Majumder S, Santacroce G, Maeda Y, et al. Endocytoscopy with automated multispectral intestinal barrier pathology imaging for assessment of deep healing to predict outcomes in ulcerative colitis. Gut. 2024;73(10):1603-1606. Published 2024 Sep 9. doi:10.1136/gutjnl-2024-332894
3Le Berre C, Flamant M, Bouguen G, et al. VALIDation of the IBD-Disk Instrument for Assessing Disability in Inflammatory Bowel Diseases in a French Cohort: The VALIDate Study. J Crohns Colitis. 2020;14(11):1512-1523. doi:10.1093/ecco-jcc/jjaa100