Introduction

Crohn’s disease (CD) is associated both (i) with polymorphisms in the card15 gene, coding for the cytosolic NOD2 innate immunity receptor, recognizing bacterial peptidoglycan (PG), and (ii) with a decrease in Faecalibacterium, an anti-inflammatory intestinal bacterium¹. Oral administration of Faecalibacterium could represent a novel therapeutic strategy for CD patients, which is currently under investigation with F. prausnitzii EXL01 strain (human clinical trial #NCT05542355). Indeed, Faecalibacterium exhibits anti-inflammatory effects both in vitro and in vivo in colitis models^1-6 and we recently discovered that it directly induced the production of Interleukin-10 (IL-10) in CD14+ human monocytes⁷. However, the bacterial molecules, the host receptors and signaling pathways involved are still poorly understood. Therefore, the aim of the current study was to decipher the role of the interaction between Faecalibacterium, its PG and NOD2 in health and CD.

Aims & Methods

The PG structure of F. prausnitzii EXL01 was determined by ultra high-performance liquid chromatography and mass spectrometry. NOD2 activation was evaluated using HEK-human NOD2 reporter cell line. Following stimulation with either bacteria or PG, secretion of IL-10 and TNF-a by i) WT and NOD2 KO THP1 human monocytic cell line and ii) by dendritic cells (DC) from WT and NOD2^-/- mice and from human patients with CD harboring 0 or 2 NOD2 loss-of-function frameshift mutations were evaluated by ELISA.

Results

Faecalibacterium PG presents an amino acid substitution in the minimal motif recognized by NOD2 (data patented). PG of F. prausnitzii activates NOD2, but not NOD1, in a dose-dependent manner and has a higher ability to activate NOD2 than the one from other Gram positive bacteria. We showed that the production of IL-10 by THP1 monocytes and murine DC upon stimulation either with F. prausnitzii or its PG was decreased in absence of NOD2, indicating that secretion of IL-10 by human and murine immune cells upon Faecalibacterium stimulation is dependent on NOD2. Interestingly, no significant effect was observed for TNF-a secretion, leading to a significant decrease of the IL-10/TNF- a ratio in NOD2 KO cells. In addition, secretion of IL-10 upon stimulation with F. prausnitzii or its PG was lower in DC from CD patients with 2 NOD2 loss-of-function frameshift mutations compared to DC from CD patients without NOD2 mutation. Levels of secreted TNF-a were higher in DC from CD patients with 2 NOD2 loss-of-function frameshift mutations compared to DC from CD patients without NOD2 mutation, leading to decreased IL-10/TNF- a ratio in absence of functional NOD2. The pathways downstream of NOD2 as well as the effects of Faecalibacterium and its PG on NOD2 in vivo are currently under investigation.

Conclusion

Our study showed that Faecalibacterium and its PG activate NOD2, and therefore the production of IL-10, in a different way than other Gram-positive bacteria. These results provide new insight into the molecular pathways underlying the immunomodulatory effects of F. prausnitzii, and highlight NOD engagement as a key immunological feature. Identification of PG as a molecule responsible for the therapeutic effects paves the way for the next generation of Faecalibacterium-based drugs, whether whole-cell or component-driven, in inflammatory diseases such as CD.

References

1. Sokol H, Pigneur B, Watterlot L, et al. Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified by gut microbiota analysis of Crohn disease patients. Proc Natl Acad Sci U S A. 2008; 105: 16731-6.
2. Lenoir M, Martin R, Torres-Maravilla E, et al. Butyrate mediates anti-inflammatory effects of Faecalibacterium prausnitzii in intestinal epithelial cells through Dact3. Gut Microbes. 2020; 12: 1-16.
3. Quevrain E, Maubert MA, Michon C, et al. Identification of an anti-inflammatory protein from Faecalibacterium prausnitzii, a commensal bacterium deficient in Crohn's disease. Gut. 2016; 65: 415-25.
4. Rossi O, van Berkel LA, Chain F, et al. Faecalibacterium prausnitzii A2-165 has a high capacity to induce IL-10 in human and murine dendritic cells and modulates T cell responses. Sci Rep. 2016; 6: 18507.
5. Sarrabayrouse G, Bossard C, Chauvin JM, et al. CD4CD8 lymphocytes, a novel human regulatory T cell subset induced by colonic bacteria and deficient in patients with inflammatory bowel disease. PLoS Biol. 2014; 12: e1001833.
6. Touch S, Godefroy E, Rolhion N, et al. Human CD4+CD8alpha+ Tregs induced by Faecalibacterium prausnitzii protect against intestinal inflammation. JCI Insight. 2022; 7.
7. https://www.biorxiv.org/content/10.1101/2024.10.06.616495v1

Disclosure

HS reports lecture fees, board membership, or consultancy from Carenity, AbbVie, Astellas, Danone, Ferring, Mayoly Spindler, MSD, Novartis, Roche, Tillots, Enterome, BiomX, Takeda, Biocodex, has stocks from Enterome and is co-founder of Exeliom Biosciences. PL report lecture fee, board membership, or consultancy from Biose, Biostime, Boiron, Bonduelle, BMS, Bromatech, IPSEN, iTaK, Lallemand, Lesaffre, L’Oréal, Mayoli, Merck, Procter and Gamble, Second Genome, Therascience and URGO and is co-founder of Exeliom Biosciences. Other authors declare no competing interests. DS, LH, PR and BH are employees of Exeliom Biosciences.

Introduction

Pancreatic cancer remains a devastating disease with a poor prognosis, and liquid biopsy utilizing minimally invasive biofluids such as blood and duodenal juice has emerged as a promising approach for early detection. Our group has previously accumulated data on plasma- and duodenal fluid-based liquid biopsy, demonstrating potential clinical utility but also highlighting limitations in diagnostic sensitivity. This study aims to establish a robust cancer diagnostic and risk assessment method using plasma, duodenal juice, and pancreatic juice, while also charactering molecular abnormalities in resected tumors and surrounding tissues. To develop a novel clinical diagnostic framework, we comprehensively evaluated to cancer-associated genetic mutations in biofluids and compared these finding with tissue samples obtained via biopsy or surgical resection.

Aims & Methods

This multi-institutional study, initiated in 2021, focuses on developing a liquid biopsy platform for pancreatic cancer detection. Samples were collected as follows: plasma (n=224), duodenal juice (n=102), and pancreatic juice (n=85). Plasma was collected in 10 mL PAXgene Blood ccfDNA tubes (BD); cell-free DNA (cfDNA) was purified and concentrated to a 30 µL eluate. Duodenal fluid was collected through the endoscopic channel, and pancreatic juice was aspirated directly from the pancreatic duct using a catheter during ERP examination. Both fluid were each mixed with a preservation solution validated in a previous study. Digital PCR (dPCR) was performed to screen for KRAS G12/G13 and A59/Q61 mutations, followed by panel-based sequencing. For this study, we designed a Duplex UMI-based pancreatic cancer gene panel targeting 16 genes, including KRAS, TP53, CDKN2A, and SMAD4, to enable high sensitive detection of tumor-specific mutations.

Results

DPCR screening detected KRAS mutations in 75% of pancreatic juice samples and 50% of duodenal juice samples. Validation of the Duplex UMI-based target sequencing panel in a subset of samples (n=16) demonstrated that a minimum input of 20 ng of liquid-derived, non-genomic DNA was necessary to achieve concordance with mutations identified in matched tissue samples. Inputs below this threshold resulted in significantly reduced coverage and uniformity. Notably, duodenal and pancreatic juice exhibited superior sensitivity, reliably detecting tissue-confirmed mutations down to a minimum variant allele frequency (VAF) of 0.1%. Pancreatic juice not only captured a diverse spectrum of genetic alterations across multiple lesions but also identified mutations absent in corresponding tissue samples, suggesting its potential for detecting subclinical molecular changes. These findings underscore the complementary roles of different biofluids in capturing tumor heterogeneity.

Conclusion

Pancreatic juice-derived DNA shows exceptional promise for the accurate prediction of tumorous lesions, offering a powerful tool to prompt further diagnostic evaluation even in the absence of histological evidence. This approach could substantially enhance early detection and risk stratification in pancreatic cancer. Our ongoing study involves comprehensive analysis of all collected samples using the designed 16-gene panel. These efforts aim to establish liquid biopsy as a central component of pancreatic cancer diagnostics, supporting personalized treatment strategy and improving patient outcomes.

Disclosure

Y.O., K.T. and Y.M. receive funding form Hitachi High-Tech Corporation

Introduction

Histopathology remains the gold standard for the assessment of diminutive (≤5 mm) colorectal polyps, but it requires considerable cost and resources allocation. Optical diagnosis supported by artificial intelligence (AI) has shown promise, though its integration into clinical decision-making is limited. Our prior work showed the feasibility of replacing histopathology with AI-assisted human optical diagnosis in real-time practice.¹

Aims & Methods

This study aimed to assess patient acceptance, and diagnostic performance of autonomous computer-aided optical diagnosis (CADx) when used as the sole determinant in resect-and-discard (RD) and diagnose-and-leave (DL) strategies.
This prospective study was conducted at the University of Montreal Hospital Center between August and November 2024 (ID: CER23.095, NCT06059378). Consecutive patients aged 45–80 years undergoing elective colonoscopy were approached and provided detailed information about the use of CADx, and the principles of the RD and DL strategies. For consented patients, procedures were performed using CADEYE system, which autonomously provided an optical diagnosis for detected diminutive polyps. Lesions predicted to be neoplastic were removed and discarded without histopathologic analysis (RD), while rectosigmoid lesions predicted to be hyperplastic were left in place (DL). All colonoscopies were video-recorded. To establish the reference standard, the videos of all polyps undergoing optical diagnosis were independently reviewed by two expert endoscopists. In cases of disagreement, a third reviewer arbitrated the final decision. The primary outcome was the proportion of patients consenting to undergo autonomous CADx. Secondary outcomes included the accuracy of the RD strategy, the negative predictive value (NPV) of the DL approach, and the agreement between CADx- and expert-driven surveillance interval recommendations.

Results

95/102 patients approached (93.1%) consented to undergo CADx-based optical diagnosis (mean age 65.7 years). Among 149 diminutive polyps detected (51 (34.2%) in the rectosigmoid and 98 (65.8%) in the proximal colon), CADx provided optical diagnosis in 98.7% (n=147) of cases. The RD and DL strategies were applied to 113 (76.9%) and 30 (20.4%) of polyps, respectively. After excluding indeterminate cases (n=5) and sessile serrated lesions (SSLs) (n=14), the RD strategy achieved an accuracy of 83.5% and the DL strategy demonstrated a NPV of 92.3%. Surveillance interval agreement between CADx and expert recommendations was 100% (95%CI 96.2-100.0). Sensitivity analyses showed reduced performance when SSLs were classified as neoplastic, but Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) benchmarks were met when SSLs were considered hyperplastic.

Table 1. Diagnostic performance of computer- assisted optical diagnosis (CADx), using expert optical diagnosis as the reference.

Conclusion

Autonomous CADx achieved high patient acceptance and met key performance benchmarks for managing diminutive polyps using RD and DL strategies. These findings support its potential for safe, real-world implementation, though further development is needed to address current limitations in SSL detection and to enable quality optical diagnosis practice.

References

1. Taghiakbari M, Rex DK, Pohl H, et al. Pragmatic Resect and Discard Implementation Using Computer-Assisted Optical Polyp Diagnosis. Gastroenterology 2025;168:154-156.e2.

Disclosure

Daniel von Renteln has received research funding from ERBE Elektromedizin GmbH, Ventage, Pendopharm, Fujifilm and Pentax, and has received consultant or speaker fees from Boston Scientific Inc., ERBE Elektromedizin GmbH, and Pendopharm. Roupen Djinbachian has received speaker fees from Fujifilm. The remaining authors declare that they have no conflict of interest.