Introduction

Although the role of the microbiome in the development of GI disease is not fully understood, there is increasing evidence to suggest a causal relationship. The microbiome is a mediator of chronic inflammation and alterations in the faecal microbiome have been reported in patients with biliary disease. Data on the spatial microbiome of the bile duct are poorly characterised. Taking advantage of the availability of biliary stents to treat obstructive cholestasis, we developed a protocol to systematically assess the biliary stent microbiome.

Aims & Methods

The aim of this study was to describe the microbial changes associated with biliary tract disease and their potential translational significance. In a prospective study, 123 patients with a total of 245 stents and 17 bile samples were included. Of these, 53 patients had a diagnosed malignant disease and 70 patients had an underlying non-malignant disease including post-operative stenosis. Using an optimised protocol, DNA was extracted from the bile duct stents and the V1-V2 region of the 16S rRNA gene was amplified by PCR and sequenced using the Illumina platform. A dedicated bioinformatics approach was used for multifactorial sample analysis.

Results

We detected 4339 phylotypes from 321 genera belonging to 14 phyla in the stents. The most abundant genera were Enterococcus, Lactobacillus and Escherichia/Shigella. When comparing the bile and stent microbiomes, we observed a high Bray-Curtis similarity, suggesting that the stent microbiome can be considered representative of the bile microbiome analysis. Comparison of the stent microbiome from patients with multiple stents also showed a high Bray-Curtis similarity, supporting the reliability, reproducibility and representativeness of single stent analysis. Cluster analysis identified three distinct microbial types that differed significantly at the clinical and microbial level (PERMANOVA p=<0.0001). The differences were associated with a disease cluster and disease-relevant laboratory parameters such as CRP, bilirubin and biliary stent indwelling time (Kruskal-Wallis test p=0.0064, p=0.0157, p=0.0061). Specifically, the stent microbiome was significantly correlated with indwelling time. Escherichia/Shigella and Dialister showed a positive correlation with indwelling time (Spearman method: r=0.2597, p=0.0064; r=0.2093, p=0.0290). Phy2 and 3 (both Enterococcus) showed a negative correlation with indwelling time (Spearman method: r=-0.2840, p=0.0025; r=-0.2894, p=0.0022). Patients with early unplanned stent dysfunction (mean 21 days) showed a significant difference in the microbiome at the genus level (PERMANOVA p=0.006) compared to patients with non-dysfunctional stents or elective stent replacement.

Conclusion

Here we report on a newly developed approach to assess the biliary microbiome using biliary stents. The bile stent microbiome can be clustered into three distinct enterotypes that are associated with clinically relevant disease phenotypes, opening the possibility for scientific and clinical exploitation of the methodology.

Introduction

Short bowel syndrome (SBS) is a severe complication of extensive small intestinal resection, most commonly occurring in Crohn’s disease (CD), a chronic inflammatory disorder defined by transmural immune infiltration. Cytokines and chemokines are central mediators in the immune cascade driving intestinal inflammation and tissue damage^1,2. Despite advances in care, no biomarkers currently predict SBS onset or progression to intestinal failure (IF). Profiling systemic cytokine and chemokine signatures may thus offer novel insight into disease trajectory and risk stratification.

Aims & Methods

This study investigates circulating inflammatory mediators in patients with established IF/SBS and CD patients at high risk of progression. A total of 150 patients with CD were enrolled and stratified into five groups based on intestinal function and surgical history: A1, SBS with IF requiring parenteral nutrition (PN) or intravenous fluids; A3, SBS without IF and inactive disease; B, high risk of IF with multiple or extensive resections; C1, low risk for IF with no history of resection; and C2, low risk for IF with prior resection. Serum cytokine and chemokine profiles were quantified at baseline (T0) and after six months (T6) using the human 27-PLEX multiplex immunoassay.

Results

Serum cytokines and chemokines profiling at baseline (T0) and after six months (T6) revealed distinct inflammatory patterns across the study groups. Patients with SBS and IF (group A1) showed persistently elevated levels of IP-10, IL-12, MIP-1α, and G-CSF, reflecting sustained immune activation. Whereas, patients at high risk of IF (group B) displayed increased Eotaxin, bFGF, IL-15, and IL-6, indicative of subclinical inflammation and possible tissue remodelling.
A general reduction in cytokine levels was observed at T6, though anti-inflammatory mediators remained minimally modulated, suggesting ongoing low-grade inflammation. Comparisons between groups highlighted divergent cytokine signatures correlating with disease severity and nutritional support requirements.

Conclusion

These findings suggest that specific circulating cytokines may serve as potential biomarkers for early identification of patients at risk of IF. The differential expression patterns observed across groups support their relevance in stratifying disease severity in CD and SBS. Further large-scale studies are needed to validate these preliminary results and to fully establish their prognostic significance.
Funded by: 2.1 “Rafforzamento e potenziamento della ricerca biomedica del SSN”, finanziato dall’Unione europea – NextGenerationEU, CUP C53C22001140007. 2022 PNRR Project “Changing the future of intestinal failure in intestinal chronic inflammation: towards innovative predictive factors and therapeutic targets” code: PNRR-MAD-2022-12376791.

References

1. Friedrich M, Pohin M, Powrie F. Cytokine Networks in the Pathophysiology of Inflammatory Bowel Disease. Immunity. 2019;50(4):992-1006. doi:10.1016/j.immuni.2019.03.017
2. Singh UP, Singh NP, Murphy EA, et al. Chemokine and cytokine levels in inflammatory bowel disease patients. Cytokine. 2016;77:44-49. doi:10.1016/j.cyto.2015.10.008

Introduction

Active inflammatory bowel disease in pregnancy is associated with an increased risk of adverse maternal and neonatal outcomes. Understanding patterns of disease activity may inform strategies for improving outcomes.

Aims & Methods

A retrospective cohort study was conducted of pregnancies managed through an IBD–antenatal clinic between August 2020 and January 2025. Patients were stratified into 2 groups based on disease activity during pregnancy. Active disease was defined using the Physician Global Assessment, symptoms, and biomarkers (CRP and/or FCP). Disease flare was defined by an increase in symptoms and/or biomarkers from their baseline. Disease activity was assessed pre-conception (within 6 months before pregnancy) during pregnancy and post-partum (up to 6 months post birth).

Results

Of 209 pregnancies (Table 1), 76.3% (n=158) were in remission and 23.7% (n=49) had active disease pre-conception. Among those with active disease, 81.6% (n=40) remained active into pregnancy, while 18.4% (n=9) achieved remission. Of those in remission at pre-conception, 73.4% (n=116) stayed in remission during pregnancy, and 24.7% (n=39) flared. 2 patients with no pre-conception data were active in pregnancy.
Of 125 patients in remission during pregnancy, 73.6% (n=92) stayed in remission post-partum and 12.0% (n=15) flared. Among 81 patients with active disease in pregnancy, 39.5% (n=32) remained active, and 53.0% (n=43) achieved remission post-partum.
Patients in remission through pregnancy had a higher mean BMI (24.5 vs 23.0 kg/m², p=0.027), were more likely to be of white ethnicity compared to minority ethnic groups (61.0% vs 38.4% p=0.0026), have a diagnosis of Crohn’s disease (58.6% vs 37.0%, p=0.0088), and be nulliparous (51.2% vs 35.0%, p=0.0414).
At conception, approximately 30% of patients in both groups were not receiving any treatment. During pregnancy, this proportion fell to 8.6% in the active group, reflecting therapy escalation. Use of biologics increased from 22.2% to 38.2% in the active group and remained stable at 36.0% in the remission group. Corticosteroid use was exclusive to the active disease cohort (6.2% at conception; 23.5% during pregnancy).
Active disease in pregnancy was associated with higher rates of adverse outcomes: gestational diabetes (12.3% vs 8.0%, p=0.001), fetal growth restriction (4.9% vs 0%, p=0.044), and low birth weight (<2500g: 14.6% vs 2.4%, p=0.015). While rates of small for gestational age infants were higher in the active group (9.9% vs 4.0%), this was not statistically significant.
Emergency c-sections were more common in the active group (29.9% vs 15.0%, p=0.03), while elective c-sections were more frequent in the remission group (27.5% vs 13.4%, p = 0.03). Women in remission more often had an intact perineum (63.6% vs 54.7%), while episiotomy was more frequent in those with active disease (18.8% vs 11.7%); both did not reach statistical significance.

Conclusion

This study underscores the impact of active IBD on maternal and neonatal outcomes.
Nearly 1 in 4 women in remission at preconception flared during pregnancy. This highlights the need for effective pre-conception counselling, access to disease monitoring tools, multidisciplinary management and timely treatment optimisation to sustain remission during pregnancy.

Disclosure

No disclosures

Introduction

Perianal fistulizing Crohn’s disease (pfCD) is a debilitating phenotype that severely impacts quality of life (QoL). pfCD frequently implies a stepwise, combined medical and surgical treatment approach. Treatment goals are ideally individual and include improvement of QoL, however precise outcomes are not determined yet. Currently, most commonly used outcomes are clinical response/remission, and radiological healing, the latter most relevant to long-term disease remission.

Aims & Methods

The aim of this study was to evaluate QoL in pfCD and compare it with clinical and radiological outcomes after 26 weeks of treatment.
In this prospective exploratory, observational cohort (AMFIBIO), we included patients with pfCD starting on anti-TNF-α therapy, mesenchymal stem cell injection (MST), or hyperbaric oxygen therapy (HBOT) combined with surgical closure. We collected patient-reported IBD-specific (IBDQ-32) and fistula-specific (CAF-QoL) QoL outcomes. MAGNIFI-CD (remission defined as MAGNIFI-CD ≤6), perianal disease activity index (PDAI; response defined as ≤4) and fistula drainage assessment (FDA) were evaluated at baseline and week 26. Paired T tests were used to analyze changes in QoL, clinical and radiological scores. Pearson’s correlation coefficients were used to correlate changes between the outcomes.

Results

Twenty-one patients were analyzed at week 26 (Table 1). Mean change between baseline and week 26 in CAF-QoL and IBDQ-32 was 13 (95%CI 3 – 23) and 9 (95%CI -5 – 24) respectively. FDA correlated moderately with improvement in CAF-QoL (ρ=0.59; 95%CI 0.19 – 0.82), and moderately with improvement in IBDQ-32 (ρ=0.49; 95%CI 0.04 – 0.77). Improvement in CAF-QoL (ρ=0.31; 95%CI -0.20 – 0.69) and IBDQ-32 (ρ=0.35; 95%CI -0.16 – 0.72) did not correlate with improvement in PDAI, nor with PDAI response (resp. ρ=0.38; 95%CI -0.009 – 0.71, and ρ=0.40; 95%CI -0.08 – 0.72). No correlation was seen between changes in CAF-QoL and MAGNIFI-CD (ρ=0.08; 95%CI -0.39 – 0.52), or MRI remission (ρ=0.22; 95%CI -0.26 – 0.61).

Table 1. Patient and fistula characteristics (n=21)

Conclusion

IBD- and fistula-specific Quality of Life scores improve after therapy at week 26 in patients with pfCD. This improvement correlates with fistula drainage assessment, however it does not correlate with PDAI and MRI outcomes.

Disclosure

LM, KB, JT and RvH have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this abstract. CB has received grants from Boehringer Ingelheim and Roche; speakers honoraria from AbbVie, Janssen, Galapagos, Takeda, and Tillotts. JS is President-elect of the European Society of Gastrointestinal and Abdominal Radiology. GD has served as consultant for AbbVie, Astrazeneca, Alimentiv, Bristol-Myers Squibb, Boehringer Ingelheim, Celltrion, Cosmo, Eli Lilly, Galapagos, GSK, Johnson and Johnson, Takeda, Pfizer Inc, Polpharma, Prometheus Biosciences, Tillotts and Ventyx; received speaker fees from AbbVie, Boehringer Ingelheim, Celltrion, Eli Lilly, Johnson and Johnson, Takeda, Pfizer Inc and Tillotts. KG has received grants from Pfizer Inc, Celltrion and Galapagos; consultancy fees from AbbVie, Arena Pharmaceuticals, Galapagos, Gilead, Immunic Therapeutics, Janssen Pharmaceuticals, Novartis, Pfizer Inc., Samsung Bioepis and Takeda and speaker’s honoraria from Celltrion, Ferring, Janssen Pharmaceuticals, Novartis, Pfizer Inc, Samsung Bioepis, Takeda and Tillotts.

Introduction

Perianal fistulas occur in up to 30% of patients with Crohn’s disease (pfCD) and frequently require a combined medical and surgical treatment approach. Hyperbaric Oxygen Therapy (HBOT) has previously shown benefit in treatment-refractory pfCD.

Aims & Methods

In this pilot study, we aim to assess the feasibility of surgical fistula closure 4 weeks after HBOT, and efficacy of combining surgical closure and 8 weeks HBOT.
Patients with complex pfCD refractory to at least 6 months of anti-TNF therapy were included in this study. All patients received a seton prior to starting treatment with 40 sessions (8 weeks) of HBOT (each lasting 110 minutes, with 5-minute air breaks) with 100% oxygen at 2.4 atmosphere. At week 4 the seton was removed, and surgical closure of the internal fistula opening was attempted. All patients continued stable dose of medical treatment during the study. Response was assessed by the fistula drainage assessment (FDA) and the perianal disease activity index (PDAI) at week 9, 26 and 52, and by pelvic MRI at week 9 and 26. MRI response was defined as a decrease of 2 points in MAGNIFI-CD score, MRI remission as a MAGNIFI-CD ≤6. (Serious) Adverse Events (AE) were reported for 52 weeks. Univariate logistical regression was used to explore potential variates associated with PDAI response (≤4) at week 26.

Results

Ten patients completed treatment and were analyzed (Table 1). All patients completed HBOT and underwent a technically successful surgical procedure at week 4. No proctitis was encountered at week 4 during examination under anesthesia. PDAI response was achieved by 30%, 60%, 58% at week 9, 26 and 52, respectively. FDA response/remission was achieved in 50%/20%, 80%/40% and 80%/50% of patients at week 9, 26 and 52, respectively. MRI response/remission was achieved in 60%/10% and 60%/20% of patients at week 9 and 26, respectively. No significant parameters were associated with PDAI response at week 26 in univariate logistical regression. (S)AEs included one patient with a potential oxygen toxicity seizure without long term effects, and one patient reported claustrophobia, no new AEs were reported.

Table 1 Patient and fistula characteristics (n=10)

Conclusion

HBOT is feasible in combination with surgical therapy in patients with complex pfCD refractory to anti-TNF therapy. Patients had long-lasting benefit of the combined treatment approach. Further translational data are currently analyzed to clarify mechanisms of action and to explore potential biomarkers for therapy response.

Disclosure

LM, KB, JT and RvH have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this abstract. JS is President-elect of the European Society of Gastrointestinal and Abdominal Radiology. GD has served as consultant for AbbVie, Astrazeneca, Alimentiv, Bristol-Myers Squibb, Boehringer Ingelheim, Celltrion, Cosmo, Eli Lilly, Galapagos, GSK, Johnson and Johnson, Takeda, Pfizer Inc, Polpharma, Prometheus Biosciences, Tillotts and Ventyx; received speaker fees from AbbVie, Boehringer Ingelheim, Celltrion, Eli Lilly, Johnson and Johnson, Takeda, Pfizer Inc and Tillotts. CB has received grants from Boehringer Ingelheim and Roche; speakers honoraria from AbbVie, Janssen, Galapagos, Takeda, and Tillotts. KG has received grants from Pfizer Inc, Celltrion and Galapagos; consultancy fees from AbbVie, Arena Pharmaceuticals, Galapagos, Gilead, Immunic Therapeutics, Janssen Pharmaceuticals, Novartis, Pfizer Inc., Samsung Bioepis and Takeda and speaker’s honoraria from Celltrion, Ferring, Janssen Pharmaceuticals, Novartis, Pfizer Inc, Samsung Bioepis, Takeda and Tillotts.

Introduction

Targeting mitochondrial function and oxidative stress is successful in animal models of IBD. NLRX1 is a mitochondrial associated protein upregulating mitochondrial metabolism: It reduces oxidative stress and decreases pro-inflammatory cell differentiation and cytokine release. NX-13 is a first-in-class, orally active, once-daily, gut-selective NLRX1 agonist with low systemic exposure in development for Ulcerative Colitis (UC). In three mouse models of IBD, NX-13 effectively activated NLRX1 to reduce inflammatory responses and disease severity. In two phase 1 studies (56 healthy subjects; 38 UC patients) NX-13 was well tolerated. Low systemic drug exposure relative to stool levels suggested a gut-selective drug distribution. Phase 1B topline results were reported previously¹. We now present data demonstrating target engagement and downstream effects consistent with the preclinical mechanism of action (MOA).

Aims & Methods

In this double-blind phase 1B trial, 36 patients with active UC (Total Mayo Score 4-10; Mayo endoscopic subscore 2-3) were randomly assigned to NX-13 250mg Immediate Release (IR), 500mg IR, 500mg Delayed Release (DR) or Placebo to be taken QD for 4 weeks. We report pharmacodynamic results based on expression of NLRX1 and downstream immunometabolic markers in colonic tissue samples collected at screening and week 4 of treatment. NLRX1 protein levels were measured by immunohistochemistry scored by a blinded pathologist, and immunometabolic markers were measured by qRT-PCR.

Results

All NX-13 treated groups showed target engagement through mean positive increases in NLRX1 expression versus placebo at week 4, with more pronounced upregulation observed in responding patients (Table 1A). Gene expression profiles after 4 weeks of treatment showed upregulation of the mitochondrial metabolism gene MT-ND3, with downstream reductions in HIF1α and NLRP3 in the NX-13 IR groups but not in the placebo group (Table 1B). NX-13 250mg IR dosed patients also displayed downstream decreases in IL-17α and IL-1β gene expression, and the 500mg IR group showed reduction in IL-1β. Changes in NLRX1 expression and immunometabolic markers correlated with clinical response to NX-13 and were numerically greater in responding IR-dosed patients compared to non-responding patients (Table 1).

Conclusion

Treatment with NX-13 induced upregulation of its target, NLRX1, as well as downstream immunometabolic signaling consistent with preclinical MOA studies. Most importantly, target engagement parallels clinical benefit. This novel mechanism of action warrants further study and is currently being evaluated in a phase 2 proof of concept study (NCT05785715).

References

¹ L Peyrin-Biroulet, S Danese, J F Colombel, F Rieder, A Yarur, B Verstockt, S Lichtiger, R Mosig, F Cataldi, B Feagan, P577 A Phase 1b Study to Evaluate Safety, Tolerability, Pharmacokinetics and Clinical Efficacy of the Nucleotide-binding oligomerization domain, Leucine rich Repeat containing X1 (NLRX1) agonist NX-13 in Ulcerative Colitis, Journal of Crohn's and Colitis, Volume 17, Issue Supplement_1, February 2023, Pages i705–i706

Disclosure

BV - AbbVie, Alimentiv, Applied Strategic, Atheneum, Biora Therapeutics, Biogen, Bristol Myers Squibb, Celltrion, Chiesi, Falk, Ferring, Galapagos, Guidepont, Inotrem, Ipsos, Janssen, MSD, Mylan, Pfizer, Progenity, R-Biopharm, Sandoz, Sossei Heptares and Takeda, Tillots Pharma, Truvion and Viatris;
SV - grants from: AbbVie, J&J, Pfizer, Takeda and Galapagos, consulting / speaking fees from: AbbVie, Abivax, AbolerIS Pharma, AgomAb, Alimentiv, Arena Pharmaceuticals, AstraZeneca, Avaxia, BMS, Boehringer Ingelheim, Celgene, CVasThera, Cytoki Pharma, Dr Falk Pharma, Ferring, Galapagos, Genentech-Roche, Gilead, GSK, Hospira, Imidomics, Janssen, J&J, Lilly, Materia Prima, MiroBio, Morphic, MrMHealth, Mundipharma, MSD, Pfizer, Prodigest, Progenity, Prometheus, Robarts Clinical Trials, Second Genome, Shire, Surrozen, Takeda, Theravance, Tillots Pharma AG, Zealand Pharma;
BS - consultant for AbbVie, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Falk, Janssen, Lilly, Pfizer, PredictImmune and Takeda; and received speaker’s fees from AbbVie, BMS, CED Service GmbH, Falk, Ferring, Janssen, Pfizer and Takeda (served as representative of the Charité);
FR - Adnovate, Agomab, Allergan, AbbVie, Arena, Boehringer-Ingelheim, Celgene/BMS, CDISC, Celsius, Cowen, Ferring, Galapagos, Galmed, Genentech, Gilead, Gossamer, Granite, Guidepoint, Helmsley, Horizon Therapeutics, Image Analysis Limited, Index Pharma, Jannsen, Koutif, Mestag, Metacrine, Mopac, Morphic, Organovo, Origo, Pfizer, Pliant, Prometheus Biosciences, Receptos, RedX, Roche, Samsung, Sanofi, Surmodics, Surrozen, Takeda, Techlab, Teva, Theravance, Thetis, UCB, Ysios, 89Bio;
SL – owns Landos Stock;
RM – employee of Landos;
FC – employee of Landos;
SD - AbbVie, Alimentiv, Allergan, Amgen, Applied Molecular Transport, AstraZeneca, Athos Therapeutics, Biogen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Celltrion, Dr Falk Pharma, Eli Lilly, Enthera, Ferring Pharmaceuticals Inc., Gilead, Hospira, Inotrem, Janssen, Johnson & Johnson, Morphic, MSD, Mundipharma, Mylan, Pfizer, Roche, Sandoz, Sublimity Therapeutics, Takeda, Teladoc Health, TiGenix, UCB Inc., Vial, Vifor;