Introduction

Despite significant advances in medical treatment options for patients with Crohn’s disease (CD), up to 30% still require bowel surgery within the first decade after diagnosis¹. Endoscopic post-operative recurrence is not uncommon with rates up to 70% recurrence at 1 year.^2,3,4 Most studies regarding endoscopic recurrence (ER) in CD were performed with non-Asians. We aimed to describe our cohort of CD patients to ascertain the number of patients who had ER within 1 year after index bowel resection and assess the factors associated with ER.

Aims & Methods

We performed a retrospective cohort study across 2 tertiary hospitals in Singapore. We identified adult patients with CD who had undergone an index bowel resection for CD between January 2000 to December 2021 with subsequent endoscopy within 6-12 months of surgery. Patients were stratified as high risk; defined as ≥1 of the following – active smoking, penetrating disease at index surgery or perianal disease. Data on disease characteristics, prior treatment, indication and type of surgery, and post operative prophylaxis was collected. ER was defined by Rutgeerts score of ≥i2. Analysis was done with SPSS v23.0.

Results

After screening 41 patients, we identified 26 patients who met the inclusion criteria. The baseline characteristics are detailed in Table 1. The majority were male (77%), with a median age of 31 years and had ileocolonic disease (L3) (69%). 9 (35%) had penetrating disease (B3). 11 (42%) patients were biologic experienced, indicating an overall therapy-refractory population. The most common indications for resection were stricturing CD (38%) and persistent inflammation (27%). Median disease duration to surgery was 553 days. 58% were classified as high risk with this group representing a more treatment experienced group with nearly half exposed to biologics prior to resection. 42% of patients received post-operative prophylaxis of either an immunomodulator or a biologic. A higher proportion of patients in the high-risk group received biologics as post-operative prophylaxis compared to the low-risk group (20% vs 9%).

The overall ER rate was 15%. Significantly, no patients on prophylaxis in either the high or low-risk groups developed recurrence. In patients without prophylaxis, the overall ER rate was 27%. This occurred in 33% in the high-risk group and 17% in the low-risk group.

Table 1: Baseline Characteristics and Endoscopic Recurrence

Conclusion

Postoperative ER within 1 year in patients without postoperative prophylaxis was 27% in our cohort. Postoperative prophylaxis with either immunomodulators or biologics shows a trend towards preventing postoperative ER within 1 year in both high and low risk patients.

References

1. Tsai L, Ma C, Dulai PS, et al. Contemporary risk of surgery in patients with ulcerative colitis and Crohn’s disease: a meta-analysis of population-based cohorts. Clin Gastroenterol Hepatol 2021;19:2031–45.e11.
2. Rutgeerts P, Geboes K, Vantrappen G, Kerremans R, Coenegrachts JL, Coremans G. Natural history of recurrent Crohn’s disease at the ileocolonic anastomosis after curative surgery. Gut. 1984;25(6):665-672.
3. Lamb CA, Kennedy NA, Raine T, et al. British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults. Gut. 2019;68(Suppl 3):s1-s106. doi:10.1136/gutjnl-2019-318484
4. Arkenbosch JHC, Beelen EMJ, Dijkstra G, et al. Prophylactic Medication for the Prevention of Endoscopic Recurrence in Crohn’s Disease: a Prospective Study Based on Clinical Risk Stratification. Journal of Crohn’s and Colitis. 2023;17(2):221-230. Doi:10.1093/ecco-jcc/jjac128

Introduction

Though small bowel capsule endoscopy (SBCE) has revolutionised the investigation of the small bowel, small lesions may still go undetected.

Aims & Methods

This was a multicentre study whose primary aim was to assess rates of detection of ampulla of Vater during SBCEs and identify any statistically significant variation between different levels of expertise and different reading speeds.
De-identified SBCE videos, selected randomly, each of 15 minutes duration from the 1^st duodenal image, were uploaded on secure virtual cloud following ethical approval, data protection clearance and patient consent. Patient age, indication for endoscopy and findings were recorded. The videos were reviewed by 7 gastroenterology experts and 6 trainees from 6 European centres. Data regarding detection of ampulla of Vater (AoV) was collected. Each video was analysed initially using the mouse-wheel and then at a speed of 10 frames per second (fps). Data was inputted into SPSS and statistical significance assessed via Kappa coefficient.

Results

Data was collected from 30 patients of whom 63.3% were males and whose median age was 63.5 years +/- 7.164. Commonest indications were iron deficiency anaemia (56.7%), small bowel Crohn’s disease (16.7%) and overt GI bleeding (13.3%). All patients were given a macrogol based osmotic laxative for bowel preparation.
The following mean detection rates of Ampulla of Vater were observed:

• trainees using mouse-wheel; 35% (10.5)
• trainees using 10fps; 21.6% (6.5)
• experts using mouse-wheel; 33.8% (10.1)
• experts using 10fps; 20.4% (6.1)

On only taking into consideration the ampullas detected by the standard, mean detection rates using mouse-wheel for trainees is 68.7% and 82.1% for experts, as compared to 50% for trainees and 55% for experts using 10fps, showing a decline in detection rate with higher reading speed.
Table 1. denotes Kappa and p values obtained by comparison of standard/trainee/expert rates in detection of ampulla of Vater.

	Mouse-wheel		10fps
	Kappa	P value	Kappa	P value
Standard vs Trainees	0.347	0.2	0.400	0.2
Standard vs Experts	0.621	0.2	0.513	0.2
Trainee group	0.135	0.75	0.109	0.2
Expert group	0.493	0.98	0.482	0.2
Trainees vs Experts	0.260	0.2	0.284	0.2

Table 1. Comparison of AoV detection

Mathematical comparison of ampulla detection in mouse-wheel vs 10fps amongst trainees resulted in Kappa 0.323 (p=0.018); and amongst experts resulted in Kappa 0.414 (p=0.01).

Conclusion

The results demonstrate that the rate of concordance in the detection of the ampulla amongst experts declines with a higher speed of reviewing a SBCE. This suggests that pathology may be potentially missed at higher reading speeds especially in the first part of the small bowel where sometimes a SBCE rushes through. A slower reading speed is advisable especially in those with limited experience in reviewing a SBCE.

Introduction

The use of 3D cell culture models, including spheroids and organoids, has proven to be a valuable method to approximate in vivo conditions in basic research. Our recent work on the pathogenesis of spontaneous bacterial peritonitis (SBP) – a life-threatening complication of liver cirrhosis with a 1-year-mortality of 66% – shows that bacteria induce the degradation of important cell-cell contact proteins upon direct contact via various processes. The resulting destabilization of the epithelial barrier enables bacterial translocation and thus represents a mechanism in the development of SBP (Haderer et al., Gut 2022). To evaluate these processes under more physiological conditions, we investigate bacterial-induced effects on cell-cell contact proteins in a 3D spheroid model and subsequently in a patient-based organoid model.

Aims & Methods

To establish the method and create a reference, spheroids were generated from colon carcinoma cell line HCT116 with a concentration of 70,000 cells/ml. Spheroid development and formation of cell-cell contacts were assessed by fluorescence microscopy. Subsequently, bacterial-induced effects on the tight junction proteins Occludin, Claudin4 and Zonulin1 as well as on the adherens junction protein E-Cadherin were investigated after up to 12 hours of bacterial co-culture using qPCR, fluorescence microscopy and Western blot analysis. Bacterial co-culture was performed with the reference strain Escherichia coli (E.coli) O6:Hnt and the E. coli strain Ont:H41, which was isolated from the ascites of a patient with SBP.
In addition, organoids were generated from intestinal biopsies of patients with liver cirrhosis and co-cultured with both bacterial strains. Bacterial-induced effects on cell-cell-contact proteins were investigated using Western blot analysis.

Results

HCT116 cells formed formed spheroids composed of viable cells with well-defined cell-cell contacts. Co-culture with E. coli for up to 12 hours led to a significant degradation of Occludin (up to 60% reduction), E-Cadherin (up to 85% reduction) and Zonulin1 (up to 95% reduction), whereas Claudin4 levels remained mostly constant. Co-culture with heat-inactivated bacteria did not affect cell-cell contacts. The intensity of these effects was dependent on the respective protein, the bacterial strain used, as well as the multiplicity of infection (MOI) and the duration of the co-culture. Degradation of Occludin could also be visualized by fluorescence microscopy.
We were then able to transfer this experimental approach to an organoid setting. Bacterial-induced degradation of the epithelial barrier was confirmed in organoids, showing a clearly visible reduction of E-Cadherin, Occludin and Zonulin1 after 8 hours of bacterial co-culture. The intensity of the effects varied depending on the bacterial strain, with the patient strain showing a slightly higher level of aggressiveness.

Conclusion

Understanding the pathophysiological changes of the intestinal epithelial barrier in patients with liver cirrhosis is essential for advancing therapeutic strategies for SBP. In this context, a representative ex vivo model is crucial to draw reliable conclusions. Our work shows that relevant mechanisms of SBP, such as bacterial-induced degradation of cell-cell contacts, can be successfully modeled in spheroids and organoids. Thus, our study provides an approach for further approximation to in vivo conditions – bridging the gap between basic research and clinical utility.

References

Haderer M, Neubert P, Rinner E, Scholtis A, Broncy L, Gschwendtner H, Kandulski A, Pavel V, Mehrl A, Brochhausen C, Schlosser S, Gülow K, Kunst C, Müller M. Novel pathomechanism for spontaneous bacterial peritonitis: disruption of cell junctions by cellular and bacterial proteases. Gut. 2022 Mar;71(3):580-592. doi: 10.1136/gutjnl-2020-321663 . Epub 2021 Mar 11. PMID: 33707230 ; PMCID: PMC8862089.

Introduction

Small bowel adenocarcinoma (SBA) are rare, but their incidence is increasing. Early diagnosis of SBA remains elusive, so that about one-third of patients are initially diagnosed with distant metastases. In clinical practice, regimens used for SBA parallel those commonly administered in the adjuvant setting for colorectal cancer, owing to its anatomic proximity. However, genomic profiling of SBA has been shown to be distinct from colorectal cancer through comprehensive analysis of genomic alterations. Therefore, it is vital to establish a distinct chemotherapy regimen for SBA based on its molecular pathological characteristics. Claudin-18 plays a key role in constructing tight junctions and altered claudin-18 expression has been documented in various human malignancies. On the basis of this, both monoclonal antibodies and claudin-18.2-specific chimeric antigen receptor engineered T-cells have been recently developed and employed in several clinical trials, showing promising results in the treatment of advanced gastroesophageal and pancreatobiliary tract cancers. However, little is known about the clinicopathological significance of claudin-18 expression in SBA.

Aims & Methods

To explore the localization of claudin-18 in human SBA tissue and draw comparisons and determine the relationship between their expression and clinicopathological factors, and genomic alterations.
We examined 50 surgical resections from patients with primary SBA for immunohistochemical analyses of claudin-18, CK7, CK20, CD10, CDX2, MUC2, MUC5AC, and MUC6 expression. DNA mismatch repair (MMR) status was defined by immunostaining for all MMR proteins; MLH1, MSH2, MLH6, and PMS2. Both MUC 2 and CD10 are markers of intestinal type tumors, whereas MUC5AC and MUC6 are markers of gastric type tumors. Tissue samples showing both gastric and intestinal phenotypes were classified as gastrointestinal type tumors, whereas those showing neither gastric nor intestinal phenotype expression were classified as null type tumors. In addition, genomic profiling was performed on 31 patients using targeted next-generation sequencing.

Results

Claudin-18 expression was observed in 46% of SBA patients. Claudin-18 expression was positively associated with cytokeratin 7 (P=0.003) and MUC5AC (P=0.020) expression, whereas it was negatively associated with MUC2 (P=0.010), CD10 (P=0.014), and CDX2 (P=0.003) expression. Tumor mucin phenotypes included gastric type (n=9), intestinal type (n=20), gastrointestinal type (n=17) and null type (n=4). Claudin-18 was more frequently expressed in gastric type (100%) than in intestinal type (30%) phenotypes (P=0.001). GNAS mutations (N=4) were found in only claudin-18 positive SBA patients, although the difference was not significant. Claudin-18 expression did not correlate with patient age at diagnosis, patient gender, site, histological type, depth of invasion, lymph node metastasis, distal metastasis, TNM stage, and MMR status. However, claudin-18 expression correlated with worse progression free survival.

Conclusion

Claudin-18 expression is associated with gastric immunophenotype and with worse progression free survival. These findings suggest that claudin-18 may be a potential therapeutic target in certain SBA cases.