Introduction

Intestinal ultrasound (IUS) is widely recognised in the monitoring of inflammatory bowel diseases (IBD) and the resolution of bowel wall thickening (transmural healing) is currently investigated as treatment goal in IBD.¹ The international bowel ultrasound- segmental activity score (IBUS-SAS) was developed to guarantee high inter-observer reliability in Crohn’s disease (CD) and data aiming to validate it are promising.^2–4 Regarding IUS in ulcerative colitis studies remain scarce. We aimed to validate IBUS-SAS in UC-patients in comparison to the established Limberg-score.⁵

Aims & Methods

Patients with established diagnosis of UC were eligible for inclusion. The IBUS-SAS in the sigmoid colon was quantified according to the IBUS-groups guidelines.² Data regarding clinical (Mayo clinical score [MCS]), endoscopic (Mayo endoscopic score [MES]; ulcerative colitis endoscopic index of severity [UCEIS]), histologic (Nancy index) and biomarker (C-reactive protein [CRP], faecal calprotectin [FC]) activity were registered. The correlations between IBUS-SAS and these parameters were analysed using Spearman’s rank test. All p-values <0,05 were considered to be statistically significant.

Results

We enrolled 51 UC patients (31 female), with a median IBUS-SAS (individual factors see table 1) of 41.6 (IQR 24.0; 62.3). The IBUS-SAS was significantly correlated with every individual parameter (p<0.001, r=0.48, 95% CI 0.22–0.67 for MCS; p<0.01, r=0.53, 95% CI 0.25–0.73 for MES; p<0.001, r=0.53, 95% CI 0.24–0.73 for UCEIS; p=0.03, r=0.36, 95% CI 0.02–0.73 for Nancy index; p<0.001, r=0.52, 95% CI 0.26–0.70 for CRP; p=0.03, r=0.61, 95% CI 0.07–0.87 for FC).
The Limberg-score showed a significant correlation to the clinical (p=0.01, r=0.36, 95% CI 0.08–0.59), endoscopic (p=0.001, r=0.50, CI 95% 0.21–0.71 for MES and p=0.001, r=0.50, 95% CI 0.21–0.71 for UCEIS) activity and CRP (p=0.02, p=0.44 95% CI 0.02–0.65), but not for histologic activity (p=0.27) and FC (p=0.14).
Overall, the correlations of the IBUS-SAS with the various disease activity parameters were stronger than their correlation with the Limberg score regarding clinical disease activity (r=0.48 vs. 0.36), the endoscopic picture (r=0.53 vs. 0.50 for MES; r=0.53 vs. 0.50 for UCEIS), histological activity (r=0.36 vs. 0.19) and the biomarkers of inflammation (r=0.52 vs. 0.44 for CRP; r=0.61 vs. 0.43 for FC).

Table 1: The distribution of the individual IBUS-SAS parameters in this UC-cohort.

Conclusion

We conclude that the IBUS-SAS shows a better correlation to established objective read-outs of disease activity in UC than previously established IUS scores and therefore seems a promising candidate for further validation as a tool for real-world disease monitoring and future clinical trials.

References

1. Neurath, M. F. & Vieth, M. Different levels of healing in inflammatory bowel diseases: mucosal, histological, transmural, barrier and complete healing. Gut 72, 2164–2183 (2023).
2. Novak, K. L. et al. Expert Consensus on Optimal Acquisition and Development of the International Bowel Ultrasound Segmental Activity Score [IBUS-SAS]: A Reliability and Inter-rater Variability Study on Intestinal Ultrasonography in Crohn’s Disease. J. Crohns. Colitis 15, 609–616 (2021).
3. Wang, L. et al. External validation and comparison of simple ultrasound activity score and international bowel ultrasound segmental activity score for Crohn’s disease. Scand. J. Gastroenterol. 58, 883–889 (2023).
4. Xu, C., Li, L., Zhang, Y., Wang, R. & Zhang, H. Diagnostic accuracy of different cross-sectional imaging techniques for disease location and activity in Crohn’s disease and external validation and comparison of MARIAs and IBUS-SAS. Abdom. Radiol. (New York) 48, 821–832 (2023).
5. Limberg, B. [Diagnosis of chronic inflammatory bowel disease by ultrasonography]. Z. Gastroenterol. 37, 495–508 (1999).
6. Lewis, J. D. et al. Use of the noninvasive components of the Mayo score to assess clinical response in ulcerative colitis. Inflamm. Bowel Dis. 14, 1660–6 (2008).

Introduction

Irritable bowel syndrome (IBS) has a worldwide prevalence of ~11%, and thus has a considerable negative impact on both society and millions of individuals. The pathophysiology of IBS is multifactorial and incompletely understood, involving low-grade inflammation in the gut, visceral hypersensitivity, increased epithelial barrier permeability, altered gut-brain interactions, and an unfavourable composition of gut microbiota. Although we currently have no cure for IBS, a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) has shown to give ~70% of patients clinically significant symptom relief.

Aims & Methods

In this study, we seek to uncover how 12 weeks of strict low-FODMAP diet affect the intestinal immune system, visceral hypersensitivity, and gut integrity in patients with IBS. We will use highly multiplexed Hyperion imaging mass cytometry to investigate the cellular microenvironments in duodenal biopsies from n = 48 patients and n = 21 healthy controls at baseline and n = 21 patients at 12-week follow-up.

Results

With basis in known literature on relevant markers in IBS, we have developed an antibody panel for use on formalin-fixed, paraffin-embedded (FFPE) duodenal tissue with Hyperion imaging mass cytometry. The panel includes 35 markers for comprehensive spatial analyses of the gut mucosa in IBS before and after diet intervention. It comprises several immune cell markers for a broad immunologic mapping, in addition to markers for gut integrity and neuro-immune communication. The panel was tested on duodenal FFPE tissue with Hyperion, and resulting images were segmented with the Steinbock framework. Downstream single-cell analysis was performed in R with the imcRtools R/Bioconductor and cytomapper packages. Different cell types, including CD4 and CD8 T cells, were identified in duodenal tissue by means of cell segmentation and unsupervised clustering.

Conclusion

Through multimodal integration of tissue analyses and clinical symptom scores before and after treatment, we aim to provide clinically meaningful intestinal biomarkers in order to improve treatment strategies for patients with IBS.

Introduction

Gastro-oesophageal reflux disease (GERD), caused by reflux of stomach contents into the oesophagus, results in discomfort and pain. Evidence suggests reflux- induced oxidative stress in oesophageal epithelial cells may have a role in GERD pathogenesis and symptom development. High mobility group box 1 (HMGB1), a nuclear protein found in most cell types, is actively released in response to oxidative stress. HMGB1 binds to TLR2, TLR4, and RAGE, leading to downstream inflammatory signalling.

Aims & Methods

Our aim was to investigate the potential role of epithelial-derived HMGB1 in the context of GERD.
Oesophageal biopsy tissue was obtained from consented healthy volunteers (N=10) and GERD patients categorised as functional heartburn (FH; N=7), non-erosive reflux disease (NERD; N=13), and erosive reflux disease (ERD; N=11) based on clinical assessment. Oesophageal HMGB1 mRNA was assessed by RT-qPCR. Tissue was used to assess protein expression of HMGB1, TLR2, TLR4, and RAGE using immunohistochemistry (IHC). Healthy oesophageal biopsies were used to assess HMGB1 release ex vivo following synthetic refluxate challenge (pH2, 1mM deoxycholate (DCA), 1mg/mL pepsin). Cellular translocation of HMGB1 was assessed using immunofluorescence in NE-1 cells in response to acidic bile salts (pH4, 1mM DCA).

Results

HMGB1 mRNA and epithelial protein expression were consistent between healthy control and GERD patients. TLR2 and TLR4 were expressed primarily on epithelial cells with cell quantification revealing TLR4 to be the predominantly expressed epithelial receptor. The proportion of TLR4+ cells was higher in ERD compared to healthy controls (1.4% ± 0.43 vs 7.2% ± 2.567; p<0.05). In contrast, RAGE was expressed exclusively on CD45+ leukocytes – predominantly in GERD phenotypes. Many RAGE+ immune cells in GERD tissue were in close apposition to sensory CGRP+ nerve fibres. Incubating NE-1 cells with acidic bile salts (10mins), but not acid alone, induced HMGB1 translocation to the cytosol (nuclear:cytosolic HMGB1 ratios: pH7 = 2.42 ± 0.19; pH4 = 2.66 ± 0.07; pH4 + DCA = 1.416 ± 0.06; p=0.0003). Challenging oesophageal biopsies with synthetic refluxate (5mins) led to release of HMGB1 over 18 hours compared to paired biopsies (218 ± 57 vs 586 ± 220 pg/mL/mg; p<0.05).

Conclusion

HMGB1 released by oesophageal epithelial cells following reflux may contribute to inflammatory pathways in GERD, particularly via TLR4 and RAGE on epithelial and immune cells, respectively. This is of particular interest in PPI-refractory GERD, due to the exaggerated role of bile salts in HMGB1 release. Further, the close proximity of RAGE+ leukocytes and CGRP+ nerve fibres may represent a cross-talk between epithelial cells, immune cells, and sensory nerves. HMGB1 may therefore be a potential new treatment target for GERD.

Introduction

Cholecystectomy (CCE) is commonly performed for treatment of gallstone disease. However, CCE may result in post-CCE syndrome (PCS) and diarrhea (PCD) in a subgroup of patients. In addition, epidemiological association of CCE with colorectal cancer (CRC) and metabolic-associated fatty liver disease (MAFLD) has raised concerns. CCE is expected to affect the enterohepatic circulation and result in gut microbiome changes. Such changes may account for clinical symptoms and risk for CRC and MAFLD. However, the spectrum and type of gut microbiome changes post-CCE has not been fully quantified and results have been inconsistent.

Aims & Methods

This systematic review aimed to clarify the effect of CCE on gut microbiome composition and the clinical impact. A systematic search was conducted on PubMed, Web of Science and Scopus in March 2024, combining keywords such as “cholecystectomy” or “post-cholecystectomy” with “gut microbiome” or “gut dysbiosis”. Reference and citation searches were conducted on included articles. Original articles irrespective of study design that described gut microbiome changes post-CCE were included. Articles were independently reviewed by two authors and data were extracted and synthesized using narrative review. The quality of studies was assessed using the Newcastle-Ottawa scale.

Results

A total of 1373 articles (after excluding duplicates) were initially selected, and after review of the titles and abstracts, 14 eligible studies were identified and the full text reviewed. There were 3 prospective cohort and 11 cross-sectional/ case control cohort studies, of which 13 examined the bacteria microbiome using 16S rRNA gene sequencing, and 1 cross-sectional study examined the fungal microbiome using ITS1 rDNA gene sequencing. Changes in microbiome diversity indices and relative abundances were inconsistent. Among 3 prospective cohort studies, an increase in phylum Bacteroidetes was observed in a study with post-CCE interval more than 3 months, but not in the study with 3-month post-CCE interval. One study reported no change at the phylum level, but an effect for the class Clostridia and the orders Clostridiales and Coriobacteriales within 3 days of CCE. An increase in phylum Bacteroidetes post-CCE was also seen in 3 other cross-sectional studies. Five studies attempted to correlate post-CCE microbiome changes with symptoms. A decreased Firmicutes/ Bacteroidetes (F/B) ratio was observed in patients with PCS/ PCD in 3 out of 5 studies. Although changes in relative abundances of taxa correlated with symptoms, these were inconsistent, with an increase in genus Prevotella being the only common finding in 2 out of these 5 studies. Other significant observations post-CCE included a decrease of the potentially beneficial genus Faecalibacterium and an increase in the opportunistic pathogen Escherichia/Shigella, as well as an attenuated aging-associated intestinal microbiota. The single cross-sectional study that examined post-CCE fungal microbiome changes found that the relative abundance of Candida glabrata and Aspergillus were enriched, and Candida albicans was depleted.

Conclusion

CCE is associated with significant changes in gut microbiome diversity and relative abundances of taxa. Such changes have been correlated with clinical symptoms. These microbiome changes may potentially explain the risk of CRC and MAFLD noted in epidemiological studies. Discordant results between studies may relate to differences in patient populations and study methodologies.