Introduction

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), are non-infectious chronic inflammatory disorders of the gastro-intestinal tract. The continuous presence of inflammatory stimuli, such as increased circulation of cytokines and danger-associated molecular patterns (DAMPs), leads to an enhanced immune response in these patients that could explain some types of disease relapse. An important receptor for DAMPS and pathogen-associated molecular patterns (PAMPs) is NLRP3, a cytosolic pattern recognition receptor. The NLRP3 inflammasome is exclusively activated by inflammatory stimuli, like DAMPs and PAMPs, and therefore not expressed without inflammation. It is thought that NLRP3 associates with ASC to recruit pro-Caspase 1 to the NLRP3 inflammasome and cleave it to its active form. In turn, Caspase 1 cleaves pro-interleukin 1 beta (IL-1β) and pro-interleukin 18 (IL-18) to their mature forms. IL-1β is a known elevated pro-inflammatory cytokine in IBD, promoting intestinal inflammation and immune cell recruitment. We hypothesized that the NLRP3 inflammasome pathway is therefore upregulated in IBD patients.

Aims & Methods

We first set out to systematically analyze gene expression of NLRP3 and IL1B in IBD patients by performing a systematic literature review and subsequent meta-analysis according to the PRISMA guidelines and Cochrane Collaboration methods. Subsequently, an observational cohort of 70 active and quiescent patients with CD or UC was sampled for whole blood, to study NLRP3 inflammasome gene regulation, protein production, assembly and secretion. We performed ex vivo LPS and ATP challenges of whole blood, with and without NLRP3 inflammasome formation inhibitor MCC950.

Results

Across thirty studies with publicly available mRNA expression data, we found NLRP3 and IL1B expression to be significantly higher in IBD patients than in non-IBD controls. In fresh IBD patient-derived whole blood, LPS and ATP stimulation activated the NLRP3-related genes, protein production and subsequent cytokine secretion. No IL-1β and IL-18 were secreted upon incubation with MCC950, suggesting a crucial role for NLRP3 inflammasome assembly in IL-1β and IL-18 production in immune cells. In patients with active IBD, the inflammasome was transcribed at a higher level than in patients in remission. However, this effect was lost on the protein level. We found a large spread in IL-1β and IL-18 production, suggesting a variation in activation of the NLRP3 inflammasome between individuals which was not related to disease activity.

Conclusion

NLRP3 and IL1B mRNA transcription is significantly increased in IBD patients compared to non-IBD controls, and significantly higher in patients with active disease than in patients in remission. While this fits the inflammatory state of active IBD, we found that the level of IL-1β and IL-18 production by the NLRP3 inflammasome is not significantly different between disease states. This suggests a variance in individual immune response to challenges, that could help identify a subset of IBD patients that would benefit from additional therapies directed at NLRP3 and IL-1β.

Introduction

Inflammatory bowel diseases are chronic disabling conditions with a complex and multifactorial aetiology, which is still not completely understood. OCTN1, an organic cation transporter could have a role in modulating the inflammatory response, whose genetic polymorphisms were associated to increased risk of inflammatory bowel diseases. Up to now, limited information exists on its role in predicting/modulating response to therapies.

Aims & Methods

The aim of this study was to evaluate the role of OCTN1 in modifying gut microbiota and immune composition to Infliximab therapy in murine colitis. Dextran sodium sulphate model of colitis on C57BL/6 mice and ocnt1 gene knockout mice was used to assess clinical efficacy of infliximab administered intravenously. Stool, colon and mesenteric lymph node samples were collected to assess differences in gut microbiota composition, histology for Rachmilewitz score and T cell populations respectively.

Results

Octn1^-/-influences microbiota profile and is associated with a worse dysbiosis in colitis mice. Infliximab treatment attenuates colitis-associated dysbiosis with increase of bacterial richness and evenness in both strains. In comparison with wild type, octn1^-/- mice have a higher baseline percentage of Treg, Tmemory, Th2 and Th17.

Conclusion

Our data support murine model to study OCTN1 genetic asset in inflammatory bowel diseases. This could be the first step to consider this membrane transporter as a biomarker in inflammatory conditions and as a predictor of response to therapies.

Introduction

Inflammatory bowel disease (IBD) is characterized by chronic inflammation due to an uncontrolled immune response orchestrated through, i.e. neutrophils. The basement membrane acts as a front-line defense promoting tissue integrity, where the α-3 chain of type IV collagen is solely expressed on the outermost layer of the mucosa. Detection of subclinical ulceration is crucial since early-stage IBD presents a unique window of opportunity for intervention, as the disease might become a self-sustaining process once deep inflammation becomes established. We therefore, wanted to develop a biomarker reflecting early tissue injury, aiding in the implementation of prompt treatment.

Aims & Methods

A competitive enzyme-linked immunosorbent assay quantifying a human neutrophil elastase (HNE) degraded fragment of type IV collagen α-3 chain was developed (C4A3-HNE). Dilution- and spiking recovery, inter- and intra-variability, and interference were evaluated. Acceptance criteria for technical validation were a recovery of 100% ±25 and an inter-intra variability of <15%. Commercial serum samples were purchased from ProteoGenex. Biological relevance was validated in an observational study from Odense University Hospital (OUH) and healthy controls. Groups were compared using Kruskal Wallis (Dunn‘s corrected).

Results

The technical validation of the C4A3-HNE assay demonstrated acceptable results for recovery, variation, and interference. Biological relevance was assessed in commercial IBD samples and healthy donors. C4A3-HNE was elevated in both CD and UC compared to healthy (p=0.001 and <0.0001)(AUC [95% CI]: 0.820 [0.669-0.971]; 0.875 [0.775-1.000]). The results were validated in an independent cohort of IBD patients (both p<0.0001). For UC, analysis showed that compared to patients in endoscopic remission, C4A3-HNE is elevated in patients with mild endoscopic activity, decreasing dose-dependently for moderate and severe disease (T1). Fecal calprotectin and CRP levels were also lower in IBD patients with high levels of C4A3-HNE (T1). With a cut-off value of 54.1 ng/ml, C4A3-HNE could significantly discriminate between mild and severe endoscopic disease (T1).

Conclusion

Our study demonstrates the biological and possible clinical relevance of the novel C4A3-HNE biomarker. The biomarker is elevated in patients with IBD compared with healthy, and high levels may reflect early mucosal damage in patients with UC. Furthermore, inflammatory markers were lower in IBD patients with high levels of C4A3-HNE, pointing towards high levels being indicative of early disease. C4A3-HNE may provide early detection of mucosal damage or prediction of relapse; however, further studies are required to assess the clinical validity of this biomarker.

Disclosure

MA, MP, MK, and JM are employees of Nordic Bioscience A/S. MK owns stocks in Nordic Bioscience A/S.

Introduction

Small bowel activity detected by endoscopy is known to be associated with unfavourable clinical outcome in Crohn’s disease, regardless of symptoms. The treat-to-target approach whereby endoscopic remission is set as a treatment target is recommended. Imaging modalities for monitoring the small bowel are limited, as well as being invasive.

Aims & Methods

In this study, our objective was to investigate which of the existing biomarkers for Crohn’s disease best indicates endoscopic small bowel activity, and whether combining the biomarkers can improve accuracy. 104 consecutive patients with ileal and ileocolonic type Crohn’s disease who underwent balloon assisted enteroscopy (BAE) at our hospital from October 2021 to August 2022 were enrolled, with clinical and laboratory data prospectively collected and analysed. BAE was evaluated using the modified Simple Endoscopic Score for CD (modified SES-CD). Ulcers were defined as those ≧ 0.5 cm.

Results

Haemoglobin, platelet count, C-reactive protein (CRP), leucine-rich alpha-2 glycoprotein (LRG), faecal calprotectin, and faecal haemoglobin values all demonstrated a significant difference in those with ulcers found on BAE. All biomarkers significantly correlated with modified SES-CD. LRG and faecal calprotectin showed the highest areas under the curve (0.841 and 0.853) by ROC analysis for detecting small bowel ulcers. LRG showed a sensitivity of 78% and specificity of 80% at a cut-off value of 13 μg/mL, whereas faecal calprotectin showed a sensitivity of 91% and specificity of 67% at a cut-off value of 151 μg/g. Dual positivity for LRG and faecal calprotectin, as well as LRG and faecal haemoglobin, both predicted the presence of ulcers with a further improved specificity of 92% and 100%. A positive result for either LRG or faecal calprotectin/haemoglobin showed an improved sensitivity of 96% and 91%. Positivity for LRG and either of the faecal biomarkers was associated with poor clinical outcome in terms of hospitalisation, surgery, and relapse.

Conclusion

This is the first study comparing the major existing biomarkers for Crohn’s disease in terms of monitoring for small bowel activity. LRG, faecal calprotectin, and faecal haemoglobin are accurate biomarkers, especially when used in combination. Patients who are dual-positive for LRG and faecal calprotectin or faecal haemoglobin should be assessed by early endoscopic evaluation of the small bowel and considered for change in treatment, as they are at higher risk for hospitalisation, relapse, and surgery.

Introduction

Carbohydrate sulfotransferase 15 (CHST15) is an enzyme biosynthesizing sulfated matrix glycosaminoglycan that modulates tissue remodeling.

Aims & Methods

We evaluated the efficacy of add-on submucosal injections of GUT-1, the RNA oligonucleotide inhibitor of CHST15, to ongoing tumor necrosis factor (TNF) antagonist treatment in patients with moderate-to-severe ulcerative colitis (UC) and insufficient response to TNF antagonists.
This was an open-label study of 250 nM of GUT-1, which was applied by endoscopic submucosal injections at weeks 0, 2 and 4 in five UC patients who lost response during maintenance treatment to TNF antagonists. The primary endpoint was the rate of endoscopic improvement at week 6 and secondary endpoints included the rates of clinical remission. All patients received follow-up observation with continuous maintenance treatment by the same TNF antagonists till the time of clinical recurrence, defined by rectal bleeding and endoscopic examination, or for overall 48 weeks (Clinical trial Registration Number: UMIN000020900).

Results

At baseline, all included patients showed insufficient clinical and endoscopic response to ongoing TNF antagonist treatment (3 for infliximab and 2 for adalimumab), as measured by modified Mayo Score (mMS) of 7.8 (95%CI: 6.2 to 9.4), Endoscopic Subscore of 2.4 (95%CI: 1.7 to 3.1), Stool Frequency Subscore of 2.8 (95%CI: 2.2 to 3.4) and Rectal Bleeding Subscore of 2.6 (95%CI: 1.9 to 3.3). At week 6, Endoscopic Subscore reduced to 1.0 (95%CI: 0.1 to 1.9) and rate of endoscopic improvement was 80% (n=4/5). mMS reduced to 1.3 (95%CI: 0.4 to 3.2) and rate of clinical remission was 60% (n=3/5). Exploratory, Nancy histological index reduced to 1.8 (95%CI: 0.2 to 3.4) at week 6 from 3.6 (95%CI: 2.9 to 4.3) at baseline. Three patients did not show any signals of clinical recurrence for 48 weeks. All three corticosteroid-dependent patients showed no corticosteroid exposure for at least 20 weeks after achieving clinical remission. During the follow-up period, clinical recurrence was observed in one patient at week 36 and another at week 44.

Conclusion

Add-on multiple injections of GUT-1 to ongoing TNF antagonist treatment was able to induce rapid and durable clinical responses in patients with TNF antagonist-refractory UC. GUT-1 was well tolerated by the patients.

Introduction

Ulcerative colitis (UC) is a refractory inflammatory bowel disease of the colon with repeated relapses and remissions that requires lifelong treatment. Previous studies indicated that proinflammatory cytokines involved the onsets and developments of UC. New treatments for targeting these cytokines, such as TNF-α, IL-12 and IL-23 have been developed in a recent decade, underlying that immune abnormalities are the core for the etiology of UC.
Platelets play a role not only in hemostatic coagulation but in inflammatory mediator by interacting with various cells in the innate and adaptive immunity. Chronic inflammatory response confers platelets activation leading to elevated platelet count and hypercoagulability. Moreover, platelets aggregates with leukocyte in active inflammatory milieu. In fact, thrombocytosis, thromboembolism and upregulation of platelet-monocyte complex (PMC) in UC patients have been reported, implying that platelets could be novel biomarker, therapeutic target and clues for elucidating the pathology of UC. However, the clinical significance of platelet activation and PMC formation in UC is not fully elucidated and few studies were conducted to assess how platelet activation contributes to disease aggravations of UC. Therefore, we comprehensively analyzed platelet activation and platelet-monocyte complex by focusing on a correlation with clinical severity of UC.

Aims & Methods

Patients with UC (n=70) including MES0-2 group (n=34) and MES3 group (n=27), diagnosed according to a combination of symptoms, endoscopic findings, histologic findings, and the absence of alternative diagnoses, and age and sex-matched healthy controls (HCs) (n =19) were enrolled for this study. We analyzed the surface markers such as CD62P, CD40L, CD63, PAC-1 and Annexin V on CD61+ platelets by flowcytometry (FCM) in patients with UC in comparison with those in healthy adults. We also analyzed the proportion of CD61+CD14+ platelet-monocyte complexes and quantified the activation of PMCs by FCM. Moreover, we also investigated the correlation among surface markers, proportion of platelet-monocyte aggregates and Mayo endoscopic score (MES) in UC patients.

Results

The expression of CD62P but not other surface markers on platelets was significantly upregulated in UC when compared to HCs (p<0.01), and was significantly upregulated in in MES3 group when compared to the MES0-2 group (P<0.001). The proportion of PMC was also higher in MES3 groups when compared to MES0-2 group (P<0.05), and was markedly reduced by treatment (P<0.05). In addition, CD16+ monocytes, phenotypically mature and pro-inflammatory cell population, were increased in patients with UC when compared to HCs (P<0.01). The expression of CD16 on monocytes aggregated with platelets was significantly higher when compered to that without platelet (P<0.001).

Conclusion

Our study suggests that platelet activation accelerates mucosal inflammation via adhesion with monocytes in UC and contributes to the aggravation of disease.

References

Semple JW, et al. Platelets and the immune continuum.
Nat Rev Immunol. 2011 Apr;11(4):264-74.
Collins CE, et al. Platelets circulate in an activated state in inflammatory bowel disease.
Gastroenterology. 1994 Apr;106(4):840-5.

Introduction

Inflammatory Bowel Diseases (IBD) are chronic inflammatory disorders characterised by alterations of acute relapses and remission. The past decades have brought substantial advances in the pharmacological management of IBD by the introduction of immunosuppressive agents, biologics and lately small molecules. Although, the sustained efficacy of the currently available anti-inflammatory therapies is still far from optimal. Therefore, the development of novel therapies represents a major unmet clinical need in this field. Recently the enrichment of the coagulation pathway genes and among these, plasminogen activator inhibitor 1 (PAI-1) was described in IBD, whereas PAI-1 emerged as a link between the epithelium and inflammation. Moreover, the genetic deletion of PAI-1 impaired the severity of experimental colitis in mice.

Aims & Methods

Based on these, our aim was to develop and test novel PAI-1 inhibitors for the treatment of IBD. Novel, peptide-based PAI-1 inhibitors were designed and screened in silico, then the selected ones were synthetized using the ixPeptide® platform. The inhibitory potential of the peptides was determined by an in vitro PAI-1 activity assay. Cytotoxicity was monitored in vitro in Hela cells with the CellTiter Glo assay. Based on the in vitro results LDN-071 was selected for further analysis. Experimental colitis was induced in mice with 3% DSS and after the induction of colitis 10 mg/bwkg LDN-071 was administrated per os for four consecutive days. The changes of body weight, spleen weight and colon length were measured. Haematoxylin eosin (HE) and Periodic acid-Schiff (PAS) staining were performed for histology. ELISA and qRT-PCR measurements were applied to analyse the mucosal cytokine expressions. In vivo toxicity of LDN-071 was determined in mice.

Results

LDN-071 significantly inhibited PAI-1 in vitro without decreasing the cell viability in a concentration range of 1µM-1mM. The administration of 10 mg/bwkg LDN-071 in the DSS-treated mice prevented the body weight loss, the development of bloody diarrhoea, the decrease of colon length and increase of the spleen weight, which were displayed by the DSS+vehicle-treated animals. The histological analysis of the colon revealed that DSS treatment induced a severe transmural inflammation, ulceration, loss of crypt structures and goblet cell depletion. Importantly, all of these parameters were significantly impaired by the administration of 10 mg/bwkg LDN-071. Additionally, mucosal gene and protein expressions of TNF-α, IL-1β and IL-6 were significantly impaired by PAI-1 inhibition. Importantly, no signs of toxicity were LDN-071 observed in mice exposed to 100 mg/bwkg LDN-071 for 7 days.

Conclusion

Our results showed that LDN-071, a novel peptide-based inhibitor of PAI-1. It significantly reduces the severity of experimental colitis in mice. We propose that the inhibition of PAI-1 could be a potential novel therapeutic strategy in IBD.

Disclosure

LDN-071 PAI-1 inhibitor is owned by Ladon Therapeutics Ltd.