bluuebunny/crossref_metadata_2025_split huggingface dataset:
P0176 Single-cell RNA sequencing reveals the immunological mechanisms underlying Anti-saccharomyces cerevisiae antibody positivity in both non-inflamed and inflamed mucosal tissues of IBD patients
Authors: Im H W , Kim K A , Choi S , Joh C S Y , Im J P , Kim B G , Kim J S , Kim H J , Koh S J 
Published: January 2025

Abstract

Background
Previous studies have shown anti-saccharomyces cerevisiae antibody (ASCA) positivity in inflammatory bowel disease (IBD) patients is associated with increased risk of developing IBD and poor prognosis. However, no comprehensive study has elucidated the ASCA positive-related immunological phenotype in non-inflamed and inflamed colonic mucosa and its clinical implications.

Methods
We collected endoscopic biopsies from 43 ulcerative colitis [28 non-inflamed sites and 43 inflamed sites] and 20 Crohn’s disease at Seoul National University Hospital. Single-cell RNA sequencing (scRNA-seq) was performed on these samples according to the ASCA positivity. First, we compared ASCA-positive and -negative samples obtained from non-lesion sites of UC patients. Second, we investigated immunologic phenotypes in inflamed mucosa based on the disease activity (remission vs active).

Results
We conducted scRNA-seq analysis of over 130,000 single cells from 28 biopsies obtained from non-inflamed tissues of UC patients. Substantial reduction in the frequency of type 3 innate lymphoid cells (ILC3) and expression of IL18 and IL22 in ILC3s, along with a significant decrease in tight junction-associated genes (TJP1, CLDN3, CLDN4) within epithelial cells were observed in the positive group[P &lt;0.05]. In addition, data from positive group exhibited decreased levels of CSF2 in ILC3s, which is likely contributing to reduced M2 macrophage polarization.
We performed scRNA-seq analysis of over 123,673 single cells from 63 biopsies obtained from inflamed tissues. In active inflamed status, the expression of IL-17A - a cytokine that helps maintain tight-junction barrier in the intestinal epithelium during inflammation was decreased in tissue-resident memory T cells (Tc17 TRM) [P 0.026]. In addition, ASCA positive resulted in decreased CD4 central memory T cells (CD4 TCM) [P 0.046], suggesting impaired gut barrier function and subsequent rapid response to reencountered antigens. Cytotoxic gene expression, including granzyme and perforin 1, was increased in CD8 T effector memory cells (CD8 TEM) [P&lt;0.05] during remission, suggesting that ongoing subclinical inflammation may develop and contribute to tissue damage.

Conclusion
These findings suggest that Saccharomyces cerevisiae infection induces immunological changes characterized by gut barrier dysfunction, rapid responses to commensal antigens, and increased cytotoxic gene expression. Based on these findings, we believe that Saccharomyces cerevisiae may serve as a potential target for preventing disease progression in patients with IBD.
P0177 Dietary prevention of undernutrition reduces intestinal inflammation in a DSS-induced model of colitis and is associated with anti-inflammatory metabolites-producing bacteria
Authors: Leboutte M , Rebollo E , Pangault C , Ribet D , Guérin C , Bôle-Feysot C , Monnoye M , Gérard P , Savoye G , Marion-Letellier R 
Published: January 2025

Abstract

Background
Patients with inflammatory bowel diseases (IBD) have a high-risk for undernutrition1. Undernutrition is associated with higher complications such as an increased mortality rate, a higher disease activity and an impaired quality of life in IBD patients. The aim of the present study was to assess whether dietary prevention of undernutrition may alleviate intestinal inflammation in mice with colitis.

Methods
Mice were fed with an enriched diet (ED; 4.7 kcal/g, 38% kcal from milk fat, 29% kcal from sucrose) or a standard diet (SD; 3.9 kcal/g, 8% kcal from milk fat) for 31 days. Colitis was chemically induced by 1% dextran sulfate sodium (DSS) in male C57BL/6 mice for 7 days. Colitis severity was assessed by monitoring inflammation-related biomarkers, as colon weight/length ratio and fecal calprotectin. Gut microbiota composition was determined by 16S rRNA gene sequencing performed on DNA extracted from cecal contents. Body weight and body composition were recorded.

Results
In SD-fed mice, DSS induced body weight loss (p&lt;0.01) associated to a decrease of fat and lean mass (p&lt;0.01). In mice with DSS-induced colitis, ED for 3 weeks prevented body weight loss (p&lt;0.001) and body composition alteration. ED prevented DSS-induced higher colon weight/length ratio and fecal calprotectin. Compared to SD, ED significantly increased relative abundance of 8 bacterial species, including Eisenbergiella tayi (log2FC=3.8474, p_adj&lt;0.01) and Lactococcus lactis (log2FC=1.6034, p_adj&lt;0.05) (Figure 1A), which are producing anti-inflammatory metabolites such as butyrate, lactate or succinate. Relative abundances of Pseudoflavonifractor capillosus and Vescimonas coprocola were negatively correlated with inflammatory markers, such as fecal calprotectin levels (r=-0.7347, p:adj=0.0332; r=-0.7846, p=0.0265, respectively) (Figure 1B).

Conclusion
Prevention of undernutrition by ED reduces DSS-induced colitis severity and is associated with higher anti-inflammatory metabolites-producing bacteria. Further studies are now required to understand the underlying mechanisms involved in these ED-induced effects.

References
1. Bischoff, S. C. et al. ESPEN guideline on Clinical Nutrition in inflammatory bowel disease. Clin Nutr 42, 352–379 (2023).
P0179 Spatial immune profiling of Crohn’s Disease fistula carcinomas - Defining a distinct cancer subtype
Authors: Lehmann M , Paclik D , Huck A , Arnold A , Kurth-Stavenhagen C , Vieth M , Treese C , Kühl A A , Siegmund B ,   German IBD Study Group (GISG)
Published: January 2025

Abstract

Background
Fistula formation is a common and debilitating complication of Crohn’s disease (CD). Although rare, CD-associated fistula carcinomas present significant diagnostic and prognostic challenges. This study aims to identify disease-specific immune cell subsets in CD-associated fistula carcinomas.

Methods
The study analyzed tissue samples from 10 CD patients with fistula carcinomas, 7 patients with CD-associated fistulas, and 6 patients with sporadic colorectal cancer (CRC). In the tumor samples, the main tumor, infiltration front, and non-involved areas were included. Using a 36-marker panel, the immune landscape was characterized through imaging mass cytometry. The samples were processed, stained, and analyzed for immune cell compositions, cell-cell interactions, and spatial microenvironments.

Results
The immune infiltrate observed in fistula carcinomas displayed similarities to both CD fistulas and CRC. Fistula-carcinoma samples exhibited elevated levels of neutrophils, B cells, and CD163high macrophages. CRC main tumor samples exhibited a higher presence of intraepithelial CD8+ lymphocytes and CD163low macrophages. The highest levels of Cleaved Caspase-3 were observed in CRC main tumor samples, which exhibited a positive correlation with CD163low macrophages and cytotoxic T cells. Conversely, a negative correlation was observed between cleaved Caspase-3 and cytotoxic T cells in fistula-carcinoma main tumor samples. The analysis of cellular microenvironments and dimensionality reduction clustering based on immune cell frequencies revealed that fistula carcinomas exhibit a unique combination of immune cell characteristics derived from both CD fistulas and CRC.

Conclusion
The immune landscape of CD-associated fistula carcinomas exhibits characteristics of both CD fistulas and CRC, indicating a complex pathogenesis driven by chronic inflammation. These findings suggest that fistula carcinomas constitute a distinct cancer subtype, necessitating further research to develop targeted therapeutic strategies.
P0180 Bifidobacterium longum alleviates dextran sulfate sodium-induced colitis through the differential regulation of Toll-like receptor 5 on enteric glial cells
Authors: Zeng Q S , Zou M , Gan H 
Published: January 2025

Abstract

Background
Inflammatory bowel disease (IBD) is a chronic immune-associated disease arising from gastrointestinal dysbiosis and subsequent immunological dysfunction. Numerous studies have reported the beneficial effects of probiotics, such as Bifidobacterium longum (BL), on IBD, while the related mechanism behind these effects have not been fully elucidated. Enteric nervous system abnormalities have increasingly been tied to the pathogenesis of IBD, with a particular focus on the role of enteric glial cells (EGC) in this context. In this study, we aim to explore the mechanism of probiotics in the treatment of IBD from the perspective of EGC.

Methods
On base of C57BL/6 mouse, TLR5 of EGC knockdown mouse model (TLR5 KD mouse) was constructed by adeno-associated virus (serum type 6) (AAV6) which carried the interference sequence of TLR5 gene (AAV6-TLR5-RNAi). Experimental colitis was induced by dextran sulfate sodium (DSS). Mice were treated with phosphate buffer solution (PBS) or BL. Disease activity index (DAI) and histological score were applied to assess the severity of colitis. The level of GDNF、IL-1β of colonic tissue were measured by ELISA. The expression of glial fibrillary acidic protein (GFAP)、toll-like receptor 5 (TLR5)、cleaved caspase-3 of colonic tissue were tested by immunofluorescence staining and quantitative PCR (qPCR).
EGC cell line, EGC CRL2690, was exposed to probiotic (Bifidobacterium longum; BL) bacteria and pathogenic (Enterohemorrhagic Escherichia coli; EHEC). Cell apoptosis rate was assessed by flow cytometry. TLRs expression in EGC CRL2690 were evaluated at both baseline and after exposure to bacteria by qPCR and western blot analysis. GDNF and IL-1β release from EGC CRL2690, following exposure to bacteria, were measured in the presence or absence of specific TLR and pathway inhibitors.

Results
The results showed that BL ameliorated DSS-induced colitis accompanied by increased expression of GDNF, while pathogenic EHEC aggravated DSS-induced colitis combined with decreased expression of GDNF. Mechanistically, BL could up-regulate the secretion of GDNF via TLR5/p38 MAPK pathway in EGC, which was different from EHEC, which could up-regulate the secretion of IL-1β through TLR2/NF-κB pathway.

Conclusion
Our results suggested a new possible mechanism whereby probiotics ameliorate DSS-induced colitis in mice by regulating EGC via TLR5, namely, BL promotes GDNF secretion in EGC through activation of p38 MAPK signaling pathway by TLR5. Meanwhile, our results suggested that probiotic, pathogenic bacteria appeared to influence the development of intestinal inflammation by differentially modulating the secretion function of EGC via different TLRs.
P0183 GSDMD regulates interactions between macrophages and intestinal epithelial cells in inflammatory bowel disease
Authors: Gao X , Zhang X 
Published: January 2025

Abstract

Background
Our previous studies have demonstrated the significant role of the GSDMD-mediated pyroptotic pathway in inflammatory bowel disease (IBD). However, there remains some controversy surrounding the research findings concerning GSDMD in IBD.

Methods
Employing lentiviral transduction techniques, we manipulated GSDMD expression levels in THP-1 and HT-29 cells, assessing the impact of GSDMD on macrophage M1 polarization and epithelial barrier function. Further, co-culturing transduced THP-1 and HT-29 cells enabled the examination of changes in the intestinal barrier. Moreover, we generated conditional knockout mice with Gsdmdflox/floxLyz2-Cre and Gsdmdflox/floxVillin1-Cre, inducing experimental colitis with dextran sodium sulfate (DSS) to evaluate mucosal macrophage phenotypes and intestinal barrier integrity. Additionally, primary macrophages and intestinal epithelial cells were co-cultured, and downstream inflammatory factors were screened through transcriptome sequencing.

Results
Knockdown of GSDMD in THP-1 cells significantly reduces CD86 expression, indicating a decrease in M1 polarization efficiency, whereas overexpression of GSDMD yields opposite results. In HT-29 cells, overexpression of GSDMD followed by LPS treatment leads to a significant decrease expression of Claudin-1, Occludin, and Zo-1, whereas knockdown of GSDMD shows the opposite outcome. ELISA results demonstrate a correlation between GSDMD expression levels and levels of LDH, IL-1β, IL-18, TNF-α, and IL-6. In the inflammatory co-culture model of THP-1 and HT-29 cells with double knockdown of GSDMD, the severity of intestinal barrier damage and release of inflammatory factors is minimal. Conversely, in the inflammatory co-culture model of THP-1 and HT-29 cells with double overexpression of GSDMD, the intestinal barrier damage and release of inflammatory factors are maximal. Following DSS-induced colitis, compared to the Gsdmdflox/flox group, two conditional knockout mice exhibit reduced inflammatory evaluation. Furthermore, the protein expression of Zo-1, Occludin, and Claudin-1 in two conditional knockout mice is significantly higher than that in the Gsdmdflox/flox group. Flow cytometry results show that the proportion of M1 macrophages in the mucosal lamina propria is significantly lower in two conditional knockout mice compared to the Gsdmdflox/flox group. Additionally, primary macrophage and intestinal epithelial cell co-culture experiments, coupled with transcriptomic sequencing, revealed IL-1β as a downstream mediator of GSDMD-mediated macrophage-epithelial cell interplay.

Conclusion
It was confirmed that GSDMD serves as a key target in the pathological interplay between macrophages and epithelial cells.
P0185 Prevalence of IBS-like symptoms in Ulcerative Colitis patients in clinical remission
Authors: Ayton D , Hoque S 
Published: January 2025

Abstract

Background
Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with a higher prevalence in patients with inflammatory bowel disease (IBD) compared to the general population. Ulcerative colitis (UC) patients frequently report symptoms such as abdominal discomfort, bloating, altered bowel habits, and worsening symptoms due to foods or stress, even during clinical remission. This study examines the prevalence of IBS-like symptoms in UC patients at an IBD clinic in a London teaching hospital.

Methods
A survey among 100 UC patients included those with active disease (flare) and in remission. Remission status was defined by: (1) faecal calprotectin levels ≤250µg/g in the last year, (2) C-reactive protein (CRP) within the normal range in the past six months, and (3) a Mayo score of 0 on a flexible sigmoidoscopy/colonoscopy within 6 months. The IBS information questionnaire was based on WHO criteria1 and included 16 questions. Data collected included disease location, year of diagnosis, gender, and current treatment.

Results
Among the 100 patients, 34% had active disease and 66% were in remission during time of survey completion and 91% on active drug management. Total symptom scores differed significantly between active and remission groups (p=0.0066), with higher scores in active disease. However, 94% of patients in remission reported 1&lt; symptom and the mean total score was 11.32 (SD ~6.08) indicating persistent symptoms. There is a female preponderance in symptoms scores than males in both active and remission states. In active disease, females had a mean score of 16.67 (SD: 5.91) vs males at 11.53 (SD: 5.66); in remission, females scored 11.77 (SD: 5.96) vs males at 9.59 (SD: 5.56). A statistically significant gender difference was found in active disease (p=0.0144) but not in remission (p=0.129).
Table 1 shows symptoms reported in remission. Bloating correlated with constipation (r=0.32, p=0.008), potentially indicating proximal constipation in UC remission. Additionally, loose stools were strongly correlated with bowel urgency (r=0.73, p=&lt;0.0001), suggesting a symptom cluster. Among remission patients, proctitis showed the highest scores, while pancolitis scored the lowest. Disease location was weakly negatively correlated with symptom scores (r=-0.19, p=0.76), as was time since UC diagnosis (r=-0.13, p=0.305).

Conclusion
This study shows that IBS-like symptoms persist in UC patients during remission, with 94% reporting 1&lt; symptom despite active drug management. Symptom clusters such as loose stools and bowel urgency and gender differences, emphasise the need for tailored, symptom-focused care. Comprehensive strategies are essential to address residual symptoms and improve quality of life for UC patients, even in remission.

References
1.World Gastroenterology Organisation. Test for Diagnosing IBS. Published 2009. Available at: https://www.worldgastroenterology.org/UserFiles/file/wdhd-2009-test-for-diagnosing-ibs.pdf
P0186 The Significance of BACH2 Expression in Mesenteric Lymph Nodes of Crohn’s Disease
Authors: Hasegawa M , Ogino T , Sekido Y , Takeda M , Hata T , Hamabe A , Miyoshi N , Uemura M , Mizushima T , Doki Y , Eguchi H 
Published: January 2025

Abstract

Background
In Crohn’s disease (CD), the active phase is characterized by lymphatic edema, mesenteric thickening, and enlarged mesenteric lymph nodes (MLNs). Numerous lymphoid follicle-like structures are observed in inflamed areas, suggesting that lymphoid follicles and germinal centers play critical roles in CD pathogenesis. Surgical resection including thickened mesentery may reduce recurrence; however, the role of MLNs remains unclear. BACH2, a key regulator of germinal center B-cell function, was analyzed to clarify its significance in MLNs from CD patients.

Methods
MLNs were collected from 28 CD patients undergoing bowel resection with lymph node dissection. Control MLNs were obtained from macroscopically and microscopically normal ileocecal regions in patients with colorectal cancer. BACH2 expression was evaluated via immunohistochemistry. MLNs with expression levels comparable to or exceeding those of normal MLNs were categorized as strong positive (SP), while those with lower expression were classified as weak positive (WP). Lymphoid structures (LS) were defined as clusters of ≥100 mononuclear cells; primary follicles lacked germinal centers, while secondary follicles contained germinal centers. Data are presented as medians.

Results
The median MLN diameter in CD patients was 5.6 mm, significantly larger than in controls (2.9 mm, P&lt;0.0001). BACH2 expression was classified as SP in 64.3% and WP in 35.7% of cases. The number of dissected lymph nodes did not differ between SP and WP groups. No significant differences were observed in the total LS count or the area of primary and secondary follicles per MLN between the groups. However, SP patients were younger at the time of surgery (33.9 vs. 51.9 years, P=0.0153) and diagnosis (22.9 vs. 40.0 years, P=0.0055). Preoperative CRP levels were lower in SP patients (0.51 vs. 2.63 mg/dL, P=0.0307), and serum albumin levels were higher (3.9 vs. 3.1 g/dL, P=0.0087). Although no significant differences were observed in postoperative endoscopic recurrence rates, recurrence was more frequent in the WP group (22.2%) compared to the SP group (6.25%).

Conclusion
Reduced BACH2 expression in MLNs was observed in 35.7% of CD patients. These patients exhibited later disease onset, higher preoperative inflammation, and poorer nutritional status, with a potential trend toward higher postoperative recurrence rates. These findings suggest that reduced BACH2 expression in MLNs may reflect impaired immune regulatory in CD.
P0191 The role of myeloid mineralocorticoid receptor and its target neutrophil gelatinase-associated lipocalin in mice with colitis
Authors: Rebollo E , Leboutte M , Jaisser F , Savoye G , Marion-Letellier R 
Published: January 2025

Abstract

Background
Intestinal fibrosis is a common complication in IBD patients with no specific treatment. In extra-intestinal conditions, mineralocorticoid receptor (MR) antagonism inhibits inflammation and fibrosis in different pathophysiological conditions. We previously showed that pharmacological antagonism of MR also inhibits experimental intestinal fibrosis through its target neutrophil gelatinase-associated lipocalin (NGAL). We now hypothesize that myeloid MR may promote the transition from inflammation to intestinal fibrosis by modulation of macrophage plasticity. We aimed to investigate whether myeloid MR or myeloid NGAL deletion prevents colitis development in mice.

Methods
Acute and chronic colitis were respectively induced by 1% dextran sodium sulfate (DSS) in myeloid MR knock-out (MyMR KO n=10, WT n= 5) and myeloid NGAL knock-out (MyNGAL KO n=6, WT n=8). Colon tissues were collected for quantitative PCR analysis of inflammatory (Il1, Il6, Arg1, Nos2, Retnla, Adgre1) and fibrotic markers (Col1a1, Tgfb1, Fn1, Mmp3, Mmp9, Igf1, Tnf, Timp1). Fecal calprotectin and lipocalin levels were analyzed by ELISA.

Results
Myeloid MR deletion significantly reduced colon TGFβ mRNA expression (P&lt;0.05) but did not impact weight loss or intestinal permeability in mice. Myeloid NGAL deletion significantly reduced colitis-induced weight loss (P&lt;0.05) and inhibited fibrosis markers such as collagen 1 and metalloproteinase mRNA expression in mice with chronic colitis (Figure 1). Myeloid MR or NGAL invalidation did not significantly affect fecal calprotectin and lipocalin levels in our experimental conditions.

Conclusion
In our pilot study, myeloid MR and myeloid NGAL deletion inhibits fibrosis development but further studies are required to confirm these findings.