A Specific Calprotectin Neo-epitope [CPa9-HNE] in Serum from Inflammatory Bowel Disease Patients Is Associated with Neutrophil Activity and Endoscopic Severity

The emerging role of neutrophil extracellular traps in ulcerative colitis

Ulcerative colitis (UC) is characterized by chronic non-recessive inflammation of the intestinal mucosa involving both innate and adaptive immune responses. Currently, new targeted therapies are urgently needed for UC, and neutrophil extracellular traps (NETs) are new therapeutic options. NETs are DNA-based networks released from neutrophils into the extracellular space after stimulation, in which a variety of granule proteins, proteolytic enzymes, antibacterial peptides, histones, and other network structures are embedded. With the deepening of the studies on NETs, their regulatory role in the development of autoimmune and autoinflammatory diseases has received extensive attention in recent years. Increasing evidence indicates that excess NETs exacerbate the inflammatory response in UC, disrupting the structure and function of the intestinal mucosal barrier and increasing the risk of thrombosis. Although NETs are usually assigned a deleterious role in promoting the pathological process of UC, they also appear to have a protective role in some models. Despite such progress, comprehensive reviews describing the therapeutic promise of NETs in UC remain limited. In this review, we discuss the latest evidence for the formation and degradation of NETs, focusing on their double-edged role in UC. Finally, the potential implications of NETs as therapeutic targets for UC will be discussed. This review aims to provide novel insights into the pathogenesis and therapeutic options for UC.

Biomarkers of tissue remodelling are elevated in serum of COVID-19 patients who develop interstitial lung disease - an exploratory biomarker study

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a viral pneumonia that can result in serious respiratory illness. It is associated with extensive systemic inflammation, changes to the lung extracellular matrix, and long-term lung impairment such as interstitial lung disease (ILD). In this study, the aim was to investigate whether tissue remodelling, wound healing, and neutrophil activity is altered in patients with COVID-19 and how these relate to the development of post-COVID ILD.

METHOD

Serum samples were collected from 63 patients three months after discharge as part of the Research Evaluation Alongside Clinical Treatment study in COVID-19 (REACT COVID-19), 10 of whom developed ILD, and 16 healthy controls. Samples were quantified using neo-epitope specific biomarkers reflecting tissue stiffness and formation (PC3X, PRO-C3, and PRO-C6), tissue degradation (C1M, C3M, and C6M), wound healing (PRO-FIB and X-FIB), and neutrophil activity (CPa9-HNE and ELP-3).

RESULTS

Mean serum levels of PC3X (p < 0.0001), PRO-C3 (p = 0.002), C3M (p = 0.009), PRO-FIB (p < 0.0001), CPa9-HNE (p < 0.0001), and ELP-3 (p < 0.0001) were significantly elevated in patients with COVID-19 compared to healthy controls. Moreover, PC3X (p = 0.023) and PRO-C3 (p = 0.032) were significantly elevated in post-COVID ILD as compared to COVID-19.

CONCLUSION

Serological biomarkers reflecting type III collagen remodelling, clot formation, and neutrophil activity were significantly elevated in COVID-19 and type III collagen formation markers were further elevated in post-COVID ILD. The findings suggest an increased type III collagen remodelling in COVID-19 and warrants further investigations to assess the potential of tissue remodelling biomarkers as a tool to identify COVID-19 patients at high risk of developing ILD.

Investigating protease-mediated peptides of inflammation and tissue remodeling as biomarkers associated with flares in psoriatic arthritis

BACKGROUND

Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. PsA disease involves flares, which are associated with increased joint inflammation and tissue remodeling. There is a need for identifying biomarkers related to PsA disease activity and flares to improve the management of PsA patients and decrease flares. The tissue turnover imbalance that occurs during the inflammatory and fibro-proliferative processes during flares leads to an increased degradation and/or reorganization of the extracellular matrix (ECM), where increased proteolysis plays a key role. Hence, protease-mediated fragments of inflammatory and tissue-remodeling components could be used as markers reflecting flares in PsA patients.

METHODS

A broad panel of protease-mediated biomarkers reflecting inflammation and tissue remodeling was measured in serum and synovial fluid (SF) obtained from PsA patients experiencing flares (acutely swollen joint[s], PsA-flare). In serum, biomarker levels assessed in PsA-flare patients were compared to controls and in early-diagnosed PsA patients not experiencing flares (referred to as PsA without flare). Furthermore, the biomarker levels assessed in SF from PsA-flare patients were compared to the levels in SF of osteoarthritis (OA) patients.

RESULTS

In serum, levels of the PRO-C3 and C3M, reflecting formation and degradation of the interstitial matrix, were found significantly elevated in PsA-flare compared to controls and PsA without flare. The remodeling marker of the basement membrane, PRO-C4, was significantly elevated in PsA-flare compared to PsA without flare. The inflammation and immune cell activity related markers, CRPM, VICM, and CPa9-HNE were significantly elevated in PsA-flare patients compared to controls and PsA without flare. In addition, VICM (AUC = 0.71), CPa9-HNE (AUC = 0.89), CRPM (AUC = 0.76), and PRO-C3 (AUC = 0.86) showed good discriminatory performance for separating PsA-flare from PsA without flare. In SF, the macrophage activity marker, VICM, was significantly elevated whereas the type II collagen formation marker, PRO-C2, was significantly reduced in the PsA-flare compared to OA. The combination of five serum markers reflecting type III and IV collagen degradation (C3M and C4M, respectively), type III and VI collagen formation (PRO-C3 and PRO-C6, respectively), and neutrophil activity (CPa9-HNE) showed an excellent discriminatory performance (AUC = 0.98) for separating PsA-flare from PsA without flares.

CONCLUSIONS

The serum biomarker panel of C3M, C4M, PRO-C3, PRO-C6, and CPa9-HNE reflecting synovitis, enthesitis, and neutrophil activity may serve as novel tool for quantitatively monitoring flares in PsA patients.

Challenges in IBD Research 2024: Precision Medicine

Precision medicine is part of 5 focus areas of the Challenges in IBD Research 2024 research document, which also includes preclinical human IBD mechanisms, environmental triggers, novel technologies, and pragmatic clinical research. Building on Challenges in IBD Research 2019, the current Challenges aims to provide a comprehensive overview of current gaps in inflammatory bowel diseases (IBDs) research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in interception, remission, and restoration for these diseases. The document is the result of multidisciplinary input from scientists, clinicians, patients, and funders, and represents a valuable resource for patient-centric research prioritization. In particular, the precision medicine section is focused on the main research gaps in elucidating how to bring the best care to the individual patient in IBD. Research gaps were identified in biomarker discovery and validation for predicting disease progression and choosing the most appropriate treatment for each patient. Other gaps were identified in making the best use of existing patient biosamples and clinical data, developing new technologies to analyze large datasets, and overcoming regulatory and payer hurdles to enable clinical use of biomarkers. To address these gaps, the Workgroup suggests focusing on thoroughly validating existing candidate biomarkers, using best-in-class data generation and analysis tools, and establishing cross-disciplinary teams to tackle regulatory hurdles as early as possible. Altogether, the precision medicine group recognizes the importance of bringing basic scientific biomarker discovery and translating it into the clinic to help improve the lives of IBD patients.

Novel biomarker profiles to improve individual diagnosis and prognosis in patients with suspected inflammatory bowel disease: protocol for the Nordic inception cohort study (NORDTREAT)

INTRODUCTION

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, can be challenging to diagnose, and treatment outcomes are difficult to predict. In the NORDTREAT cohort study, a Nordic prospective multicentre study, we aim to identify novel molecular biomarkers of diagnostic value by assessing the diagnostic test accuracy (cross-sectionally), as well as the prognostic utility when used as prognostic markers in the long-term (cohort study). In the diagnostic test accuracy study, the primary outcome is a successful diagnosis using one or more novel index tests at baseline compared with the ECCO criteria as the reference standard. The composite outcome of the prognostic utility study is 'severe IBD' within 52 weeks from inclusion, defined as one or more of the following three events: IBD-related surgery, IBD-related hospitalisation or IBD-related death.

METHODS AND ANALYSIS

We aim to recruit 800 patients referred on suspicion of IBD to this longitudinal observational study, a collaboration between 11 inclusion sites in Denmark, Iceland, Norway and Sweden. Inclusion will occur from February 2022 until December 2023 with screening and baseline visits for all participants and three outcome visits at weeks 12, 26 and 52 after baseline for IBD-diagnosed patients. Biological material (blood, faeces, biopsies, urine and hair), clinical data and lifestyle information will be collected during these scheduled visits.

ETHICS AND DISSEMINATION

This study will explore novel biomarkers to improve diagnostic accuracy and prediction of disease progression, thereby improving medical therapy and the quality of life for patients with IBD.The study is approved by the Ethics Committee (DK: S-20200051, v1.4, 16.10.2021; IS: VSNb2021070006/03.01, NO: 193064; SE: DNR 2021-05090) and the Danish Data Protecting Agency (20/54594). Results will be disseminated through peer-reviewed journals, patient associations and presentations at international conferences.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05414578; Pre-results.

Serum Calprotectin in the Evaluation of Gastrointestinal Diseases: An Ace up Your Sleeve?

Background: Calprotectin (CP) is a calcium- and zinc-binding protein that plays a key role in innate immunity and in the recruitment of inflammatory cells. CP can be detected both in serum and in fecal samples. Serum CP (sCP) is more specific for autoimmune diseases, while fecal CP (fCP) has been well investigated for gastrointestinal diseases. Few studies have shown the clinical effectiveness of sCP as an acute-phase biomarker for gastrointestinal diseases. Aim: The aim of this narrative review is to discuss the role of sCP as a useful alternative biomarker of the acute-phase activity of gastrointestinal diseases and as a possible tool for screening and monitoring these diseases. Material and Methods: We searched original articles, abstracts, reviews, case reports, and clinical trials on PubMed®, Up-to-Date®, and Medscape® in the last ten years. Conclusion: We found that sCP could represent a useful biomarker in the evaluation of the inflammatory stage in patients with immune-mediated gastrointestinal diseases, but more studies are needed to promote its routine use in clinical practice as a diagnostic and prognostic biomarker as a replacement for fCP.

Neutrophils: from IBD to the gut microbiota

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract that results from dysfunction in innate and/or adaptive immune responses. Impaired innate immunity, which leads to lack of control of an altered intestinal microbiota and to activation of the adaptive immune system, promotes a secondary inflammatory response that is responsible for tissue damage. Neutrophils are key players in innate immunity in IBD, but their roles have been neglected compared with those of other immune cells. The latest studies on neutrophils in IBD have revealed unexpected complexities, with heterogeneous populations and dual functions, both deleterious and protective, for the host. In parallel, interconnections between disease development, intestinal microbiota and neutrophils have been highlighted. Numerous IBD susceptibility genes (such as NOD2, NCF4, LRRK2, CARD9) are involved in neutrophil functions related to defence against microorganisms. Moreover, severe monogenic diseases involving dysfunctional neutrophils, including chronic granulomatous disease, are characterized by intestinal inflammation that mimics IBD and by alterations in the intestinal microbiota. This observation demonstrates the dialogue between neutrophils, gut inflammation and the microbiota. Neutrophils affect microbiota composition and function in several ways. In return, microbial factors, including metabolites, regulate neutrophil production and function directly and indirectly. It is crucial to further investigate the diverse roles played by neutrophils in host-microbiota interactions, both at steady state and in inflammatory conditions, to develop new IBD therapies. In this Review, we discuss the roles of neutrophils in IBD, in light of emerging evidence proving strong interconnections between neutrophils and the gut microbiota, especially in an inflammatory context.

Neutrophil extracellular traps: a catalyst for atherosclerosis

Neutrophil extracellular traps (NETs) are network-like structures released by activated neutrophils. They consist mainly of double-stranded DNA, histones, and neutrophil granule proteins. Continuous release of NETs in response to external stimuli leads to activation of surrounding platelets and monocytes/macrophages, resulting in damage to endothelial cells (EC) and vascular smooth muscle cells (VSMC). Some clinical trials have demonstrated the association between NETs and the severity and prognosis of atherosclerosis. Furthermore, experimental findings have shed light on the molecular mechanisms by which NETs contribute to atherogenesis. NETs play a significant role in the formation of atherosclerotic plaques. This review focuses on recent advancements in the understanding of the relationship between NETs and atherosclerosis. It explores various aspects, including the formation of NETs in atherosclerosis, clinical trials investigating NET-induced atherosclerosis, the mechanisms by which NETs promote atherogenesis, and the translational implications of NETs. Ultimately, we aim to propose new research directions for the diagnosis and treatment of atherosclerosis.

Identification of patient endotypes and adalimumab treatment responders in axial spondyloarthritis using blood-derived extracellular matrix biomarkers

OBJECTIVE

To explore the potential of a panel of ECM remodelling markers as endotyping tools for axial spondyloarthritis (axSpA) by separating patients into subtypes and investigate how they differ among each other in disease activity scores and response to treatment with adalimumab.

METHODS

In three axSpA studies, a panel of 14 blood-based ECM biomarkers related to formation of collagen (PRO-C2, PRO-C3, PRO-C6), degradation of collagen by metalloproteinases (C1M, C2M, T2CM, C3M, C4M, C6M, C10C), matrix metalloproteinase (MMP)-degraded prolargin (PROM), MMP-degraded and citrullinated vimentin (VICM), basement membrane turnover (PRO-C4) and neutrophil activity (CPa9-HNE) were assessed to enable patient clustering (endotyping). MASH (n=41) was a cross-sectional study, while Adalimumab in Axial Spondyloarthritis study (ASIM,n=45) and Danish Multicenter Study of Adalimumab in Spondyloarthritis (DANISH, n=49) were randomised, double-blind placebo-controlled trials of adalimumab versus placebo every other week for 6 or 12 weeks, respectively, followed by active treatment. Biomarker data were log-transformed, standardised by mean centering and scaled by the SD prior to principal component analysis and K-means clustering.

RESULTS

Based on all three studies, we identified two orthogonal dimensions reflecting: (1) inflammation and neutrophil activity (driven by C1M and CPa9-HNE) and (2) collagen turnover (driven by PRO-C2). Three endotypes were identified: high inflammation endotype (Endotype1), low inflammation endotype (Endotype 2) and high collagen turnover endotype (Endotype3). Endotype1 showed higher disease activity (Ankylosing Spondylitis Disease Activity Score (ASDAS)) at baseline compared with Endotype2 and Endotype3 and higher percentage of patients responding to adalimumab based on ASDAS clinical improvement at week 24. Endotype3 showed higher percentage of patients with 50% improvement in Bath Ankylosing Spondylitis Disease Activity Index response at week 24 compared with Endotype2.

CONCLUSION

These endotypes differ in their tissue remodelling profile and may in the future have utility for patient stratification and treatment tailoring.

Blood-Based Biomarkers Reflecting Protease 3 and MMP-12 Catalyzed Elastin Degradation as Potential Noninvasive Surrogate Markers of Endoscopic and Clinical Disease in Inflammatory Bowel Disease

Chronic inflammation in inflammatory bowel disease (IBD) triggers significant extracellular matrix remodeling, including elastin remodeling, leading to severe clinical complications. Novel methods to assess intestinal tissue destruction may act as surrogate markers of endoscopic disease activity, relieving patients of invasive endoscopy. We explored the noninvasive blood-based biomarkers ELP-3 and ELM-12, measuring elastin degradation in IBD. In a study involving 104 Crohn's disease (CD), 39 ulcerative colitis (UC), and 29 healthy donors, we assessed these biomarkers' association with endoscopic and clinical disease activity using ELISA. Patients were evaluated based on the SES-CD and CDAI for CD patients and modified MES and partial Mayo for UC patients. ELP-3 and ELM-12 were elevated in patients with IBD. Discerning CD patients in endoscopic remission and mild from moderate to severe, ELP-3 provided an AUC of 0.69 and ELM-12 an AUC of 0.73. The ELP-3 biomarker was associated with UC patients and provided the highest diagnostic power of 0.87 for remission vs. active clinical disease. The data suggest an association of ELP-3 with active CD and ELM-12 with endoscopic remission in CD patients. Additionally, ELP-3 could identify UC patients with active clinical disease from patients in remission. The noninvasive biomarkers ELP-3 and ELM-12 could be potential surrogate biomarkers of elastin degradation and endoscopic and clinical disease markers.

A Serological Neoepitope Biomarker of Neutrophil Elastase-Degraded Calprotectin, Associated with Neutrophil Activity, Identifies Idiopathic Pulmonary Fibrosis and Chronic Obstructive Pulmonary Disease More Effectively Than Total Calprotectin

Neutrophil activation can release neutrophil extracellular traps (NETs) in acute inflammation. NETs result in the release of human neutrophil elastase (HNE) and calprotectin, where the former can degrade the latter and generate protein fragments associated with neutrophil activity. We investigated this in chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) using the novel neoepitope biomarker CPa9-HNE, quantifying a specific HNE-mediated fragment of calprotectin in serum. CPa9-HNE was compared to total calprotectin. Initially, CPa9-HNE was measured in healthy (n = 39), COPD (n = 67), and IPF (n = 16) serum using a neoepitope-specific competitive enzyme-linked immunosorbent assay. Then, a head-to-head comparison of CPa9-HNE and total calprotectin, a non-neoepitope, was conducted in healthy (n = 19), COPD (n = 25), and IPF (n = 19) participants. CPa9-HNE levels were significantly increased in COPD (p < 0.0001) and IPF subjects (p = 0.0001) when compared to healthy participants. Additionally, CPa9-HNE distinguished IPF (p < 0.0001) and COPD (p < 0.0001) from healthy participants more effectively than total calprotectin for IPF (p = 0.0051) and COPD (p = 0.0069). Here, CPa9-HNE also distinguished IPF from COPD (p = 0.045) participants, which was not observed for total calprotectin (p = 0.98). Neutrophil activity was significantly higher, as assessed via serum CPa9-HNE, for COPD and IPF compared to healthy participants. Additionally, CPa9-HNE exceeded the ability of non-neoepitope calprotectin serum measurements to separate healthy from lung disease and even COPD from IPF participants, indicating that neutrophil activity is essential for both COPD and IPF.

Identification of immune-related hub genes contributing to the pathogenesis, diagnosis, and remission of ulcerative colitis by integrated bioinformatic analyses

The inflammatory disease ulcerative colitis (UC) is multifaceted, immune-mediated, chronic, and relapsing, which is considered to be mainly driven by dysregulated mucosal immune response. The remission of the inflammatory response is a marker of mucosal healing, relating to the low risk of hospitalizations, colorectal cancer, and colectomy. In spite of this, it is still unclear what the key immunological mechanism is which contributes to UC. Here, we explored the immune mechanism and related key genes underlying the state of inflammation in UC. Co-expression networks were constructed based on the expression profiles of immune-related genes in GSE179285. Using Weighted Gene Co-expression Network Analysis and Protein-protein interactions analysis, common hub genes were identified in the module of interest. Then, screening of real hub genes, significantly differentially expressing in inflamed UC, was carried out by Differential Expression Genes Analysis of GSE75214, GSE53306, and GSE6731datasets and immunohistochemistry of clinical samples. The diagnosis Capacity of the hub gene was identified by "glm" function in R. The potential key immune-related mechanisms were investigated using functional enrichment analysis and gene set enrichment analysis (GSEA). Bioinformatics tools were used to predict potential upstream transcription factors (TF), including the UCSC genome browser, correlation analyses, and JASPAR browser. The analysis revealed the blue module, consisting of 227 immune-related genes, showed the highest correlation with inflamed UC. And then, forty-three common candidates were distinguished. S100A9 was identified within the key module as a real hub gene with good diagnostic performance. The immune genes in the blue module were markedly enriched in the Cytokine-Cytokine receptor interaction. S100A9 most likely gets involved NOD-like receptor (NLR) signaling pathway. SPI1 showed the strongest likelihood to be the regulator. S100A9 was identified as the real immune-related hub gene for inflamed UC. Both diagnosis and remission may be aided by its high expression in the inflamed UC.

Extracellular matrix remodeling proteins as biomarkers for clinical assessment and treatment outcomes in eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic progressive inflammatory disease of the esophagus, characterized by extracellular matrix remodeling and fibrotic stricture formation. Disease monitoring requires multiple re-endoscopies with esophageal biopsies. Hence non-invasive methods for determining tissue fibrosis and treatment efficacy are warranted.

AIMS

To investigate the ability of extracellular matrix proteins in serum as potential biomarkers of tissue remodeling and clinical, endoscopic, and histological disease outcomes in adult EoE patients.

METHODS

Protein-fingerprint assays were used to measure neo-epitope specific fragments of collagen remodeling, human-neutrophil elastase degraded calprotectin, and citrullinated or non-citrullinated vimentin in the serum of an adult EoE-cohort. Biomarker analysis, symptoms, endoscopic features and histological disease activity (eosinophils(eos) per high-power-field(hpf)) were evaluated at baseline and after six weeks of dietary intervention.

RESULTS

Patients with a baseline (Endoscopic Reference score) EREFS fibrosis subscore ≥ 2 presented with increased fibrolysis of cross-linked type III collagen (CTX-III) (p < 0.01), whereas low CTX-III levels were observed in patients achieving histological remission (< 15 eos/hpf) (vs. no histological remission (p < 0.05). Progression of endoscopic fibrosis after intervention was associated with increased levels of type-III (PRO-C3) and -VI collagen (PRO-C6) formation (all; p < 0.05). A baseline EREFS inflammatory subscore ≥ 2 correlated with higher neutrophilic activity (Cpa9-HNE) at week 6 (p < 0.05). Moreover, increased degradation of type-III (C3M) and -IV (C4M/PRO-C4) collagens were associated with remission of food impaction after intervention (all; p < 0.05).

CONCLUSION

Serum extracellular matrix remodeling proteins demonstrated potential as surrogate biomarkers for assessing histological disease remission, endoscopic fibrosis, and remission of symptoms of food impaction after diet intervention in adult EoE patients.

Extracellular matrix turnover biomarkers reflect pharmacodynamic effects and treatment response of adalimumab in patients with axial spondyloarthritis-results from two randomized controlled trials

OBJECTIVE

To investigate if extracellular matrix (ECM) blood-based biomarkers reflect the pharmacodynamic effect and response to TNF-α inhibitor therapy (adalimumab, ADA), in patients with axial spondyloarthritis (axSpA).

METHODS

We investigated ECM biomarkers in two randomized, double-blind, placebo-controlled trials of axSpA patients (DANISH and ASIM, n = 52 and n = 49, respectively) receiving ADA 40 mg or placebo every other week for 12 and 6 weeks, respectively, and thereafter ADA to week 48. Serum concentrations of degraded type I (C1M), II (C2M, T2CM), III (C3M), IV (C4M), VI (C6M), type X (C10C) collagen; metabolite of C-reactive protein (CRPM), prolargin (PROM), citrullinated vimentin (VICM), calprotectin (CPa9-HNE); and formation of type II (PRO‑C2), III (PRO‑C3), and VI (PRO‑C6) turnover of type IV collagen (PRO-C4) were measured at baseline and weeks 6 or 12, 24, and 48. The pharmacodynamic effect and treatment response to ADA was evaluated by linear mixed models, and correlations between biomarkers and clinical scores were assessed by Spearman's correlation.

RESULTS

C1M, C3M, C4M, C6M, CRP, PRO-C4, and CPa9-HNE levels declined after 6 or 12 weeks in patients receiving ADA compared to placebo (all p < 0.05). Patients with AS Disease Activity Score C-reactive protein (ASDAS CRP) major improvement and/or clinically important improvement had significantly higher C1M, C3M, C4M, C6M, and PRO-C4 levels than patients with no/low improvement at baseline (all p < 0.05). Baseline levels of biomarkers showed weak to moderate correlations with ASDAS and structural damage scores.

CONCLUSION

ECM metabolites showed a pharmacodynamic effect and were associated with ASDAS response during TNF-α inhibitor treatment in patients with axSpA.

Fecal Biomarkers of Neutrophil and Eosinophil Origin Reflect the Response to Biological Therapy and Corticosteroids in Patients With Inflammatory Bowel Disease

INTRODUCTION

Fecal calprotectin (FC) is a noninvasive tool for examining response to biologics in inflammatory bowel disease (IBD), but its performance in relation to other novel fecal markers of various cellular origins is unknown.

METHODS

We performed a prospective multicenter cohort study and included patients with active IBD who provided a fecal sample at initiation of biological therapy. Levels of FC, myeloperoxidase (MPO), human neutrophil lipocalin (HNL), and eosinophil-derived neurotoxin (EDN) were analyzed and related to clinical remission status at 3 months. Changes in levels of markers at 3 months were calculated, and the impact of concomitant use of corticosteroids at baseline was estimated.

RESULTS

In patients achieving clinical remission (n = 27), a decrease in levels of FC ( P = 0.005), MPO ( P < 0.001), HNL ( P < 0.001), and EDN ( P < 0.001) was observed, whereas no significant decrease was seen in patients not achieving remission (n = 39). There was a significant difference in the change in the level of MPO ( P = 0.01) and HNL ( P = 0.02) between patients achieving clinical remission and those who did not, but changes in FC and EDN could not differentiate between these groups. Patients with concomitant systemic corticosteroids at inclusion had lower levels of HNL ( P = 0.01) and EDN ( P < 0.001) at baseline, compared with patients without corticosteroids.

DISCUSSION

Fecal MPO, HNL, and EDN are all promising biomarkers for assessing the treatment outcome of biologics in patients with IBD. Fecal levels of EDN and HNL are significantly affected by corticosteroids indicating a greater sensitivity to the effects of corticosteroids compared with levels of FC and MPO.

Current and emerging biomarkers for ulcerative colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic illness requiring lifelong management that could be enhanced by personalizing care using biomarkers.

AREAS COVERED

The main biomarker discovery modalities are reviewed, highlighting recent results across the spectrum of applications, including diagnostics (serum anti-αvβ6 antibodies achieving an area under the curve [AUC] = 0.99; serum oncostatin M AUC = 0.94), disease activity assessment (fecal calprotectin and serum trefoil factor 3: AUC > 0.90), prognostication of the need for treatment escalation (whole blood transcriptomic panels and CLEC5A/CDH2 ratio: AUC > 0.90), prediction of treatment response, and early identification of patients with subclinical disease. The use of established biomarkers is discussed, along with new evidence regarding autoantibodies, proteins, proteomic panels, transcriptomic signatures, deoxyribonucleic acid methylation patterns, and UC-specific glycomic and metabolic disturbances.

EXPERT OPINION

Novel biomarkers will pave the way for optimized UC care. However, validation, simplification, and direct clinical translation of complex models may prove challenging. Currently, few candidates exist to assess key characteristics, such as UC susceptibility, histological disease activity, drug response, and long-term disease behavior. Further research will likely not only reveal new tools to tackle these issues but also contribute to understanding UC pathogenesis mechanisms.

High-affinity peptides developed against calprotectin and their application as synthetic ligands in diagnostic assays

Common inflammatory disorders such as ulcerative colitis and Crohn's disease are non-invasively diagnosed or monitored by the biomarker calprotectin. However, current quantitative tests for calprotectin are antibody-based and vary depending on the type of antibody and assay used. Additionally, the binding epitopes of applied antibodies are not characterized by structures and for most antibodies it is unclear if they detect calprotectin dimer, tetramer, or both. Herein, we develop calprotectin ligands based on peptides, that offer advantages such as homogenous chemical composition, heat-stability, site-directed immobilization, and chemical synthesis at high purity and at low cost. By screening a 100-billion peptide phage display library against calprotectin, we identified a high-affinity peptide (K_d = 26 ± 3 nM) that binds to a large surface region (951 Ų) as shown by X-ray structure analysis. The peptide uniquely binds the calprotectin tetramer, which enabled robust and sensitive quantification of a defined species of calprotectin by ELISA and lateral flow assays in patient samples, and thus offers an ideal affinity reagent for next-generation inflammatory disease diagnostic assays.

Circulating Calprotectin (cCLP) in autoimmune diseases

BACKGROUND AND AIM

Calprotectin (CLP) is a heterodimeric complex formed by two S100 proteins (S100A8/A9), which plays a pivotal role in innate immunity. Due to its intrinsic cytotoxic and proinflammatory properties, CLP controls cell differentiation, proliferation and NETosis and has been associated with a wide range of rheumatic diseases. Our review summarizes the widespread interest in circulating CLP (cCLP) as a biomarker of neutrophil-related inflammation, in autoimmune rheumatic disease (ARD) and non-ARD.

METHODS

A thorough literature review was performed using PubMed and EMBASE databases searching for circulating calprotectin and synonyms S100A8/A9, myeloid-related protein 8/14 (MRP8/MRP14), calgranulin A/B and L1 protein in addition to specific ARDs and autoimmune non-rheumatic diseases. We selected only English-language articles and excluded abstracts without the main text.

RESULTS

High cCLP serum levels are associated with worse structural outcomes in rheumatoid arthritis and to a lesser extent, in spondyloarthritis. In addition, cCLP can predict disease relapse in some autoimmune diseases including systemic lupus erythematosus (SLE), anti-neutrophil cytoplasmic antibodies-associated vasculitis (AAV) and some severe manifestations of connective tissue diseases, such as glomerulonephritis in SLE, AAV, juvenile idiopathic arthritis, adult-onset Still's disease and lung fibrosis in systemic sclerosis. Therefore, cCLP levels enable the identification of patients who need an accurate and tight follow-up. The clinical usefulness of cCLP as an inflammatory marker has been suggested for inflammatory/autoimmune non-rheumatic diseases, and especially for the monitoring of the inflammatory bowel diseases patients. Currently, there are only a few studies that evaluated the cCLP efficacy as a clinical biomarker in inflammatory/autoimmune non-rheumatic diseases with controversial results. Future studies are warranted to better clarify the role of cCLP in relation to the disease severity in myasthenia gravis, multiple sclerosis, chronic inflammatory demyelinating polyneuropathy, Graves' orbitopathy, autoimmune bullous diseases and uveitis.

CONCLUSION

Our literature review supports a relevant role of cCLP as potential prognostic biomarker mirroring local or systemic inflammation, especially in chronic inflammatory rheumatic diseases.

Do circulating neutrophil extracellular traps predict recurrence in early breast cancer?

Background

Neutrophil extracellular traps (NETs), three-dimensional structures formed by neutrophil enzymes such as neutrophil elastase (NE) and nuclear components (DNA), have been associated with progression and metastasis in breast cancer (BC). Thus, the aim of this study was to evaluate the association of circulating NETs with clinicopathological characteristics and outcomes in early BC.

Methods

A prospective cohort included women with newly diagnosed early BC. NETs were defined as the presence of NE-DNA complexes in plasma, measured by optical density. Levels of NETs were dichotomized according to the median, as low and high levels of circulating NETs. Fisher's exact test was used to evaluate associations between NETs and clinicopathological characteristics and outcomes. Survival was assessed using the Kaplan Meier method and log-rank test.

Results

Forty patients were included, 23 (57.5%) patients with low and 17 (42.5%) with high levels of circulating NETs. No associations were found between clinicopathological characteristics and circulating NETs levels. Recurrence (p = 0.99) and site of recurrence (p = 0.99) were not statistically associated with plasma NETs levels. Overall, recurrence-free survival was not statistically different between circulating levels of NETs.

Conclusions

With a short follow-up and low number of events, our results suggest that circulating levels of NETs at diagnosis of early BC are not associated with more aggressive clinicopathological characteristics, recurrence, or site of recurrence.

Advances in research on the effectiveness and mechanism of Traditional Chinese Medicine formulas for colitis-associated colorectal cancer

Inflammatory bowel disease (IBD) can progress into colitis-associated colorectal cancer (CAC) through the inflammation-cancer sequence. Although the mechanism of carcinogenesis in IBD has not been fully elucidated, the existing research indicates that CAC may represent a fundamentally different pathogenesis pattern of colorectal cancer. At present, there is no proven safe and effective medication to prevent IBD cancer. In recent years, Chinese medicine extracts and Chinese medicine monomers have been the subject of numerous articles about the prevention and treatment of CAC, but their clinical application is still relatively limited. Traditional Chinese Medicine (TCM) formulas are widely applied in clinical practice. TCM formulas have demonstrated great potential in the prevention and treatment of CAC in recent years, although there is still a lack of review. Our work aimed to summarize the effects and potential mechanisms of TCM formulas for the prevention and treatment of CAC, point out the issues and limitations of the current research, and provide recommendations for the advancement of CAC research in the future. We discovered that TCM formulas regulated many malignant biological processes, such as inflammation-mediated oxidative stress, apoptosis, tumor microenvironment, and intestinal microecology imbalance in CAC, through a review of the articles published in databases such as PubMed, SCOPUS, Web of Science, Embase, and CNKI. Several major signal transduction pathways, including NF-κB, STAT3, Wnt/β-catenin, HIF-1α, and Nrf2, were engaged. TCM formula may be a promising treatment candidate to control the colitis-cancer transformation, however further high-quality research is required.

Pursuing neutrophils: systematic scoping review on blood-based biomarkers as predictors of treatment outcomes in inflammatory bowel disease

Background

Long-term management of inflammatory bowel diseases (IBD) is challenging and the identification of reliable predictors for treatment outcomes is an unmet need. Neutrophil-related biomarkers have been mainly studied in the feces, but blood analyses have inherent advantages.

Objective

To review the recent learnings on the ability of blood-based neutrophil-expressed biomarkers to predict treatment outcomes in IBD.

Design

Systematic scoping review.

Data sources and methods

We performed a literature search in Pubmed, EMBASE, SCOPUS, Web of Science, ScienceDirect, and Cochrane Central Register of Controlled Trials from inception until May 2022 according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. All human studies associating blood-based neutrophil-related compounds with the prediction of disease progression, complication onset, or treatment outcomes were included.

Results

From 1032 retrieved entries, 34 studies were selected, 32 published in 2013 or later. In all, 17 biomarkers from granules, cytoplasm, plasmatic membrane, and plasma were explored. In total, 1850 Crohn's disease (CD) and 1122 ulcerative colitis non-duplicated patients were included. The most mentioned biomarkers were nCD64, serum calprotectin (SC), oncostatin M (OSM), neutrophil elastase-generated calprotectin fragment (CPa9-HNE), and triggering receptor expressed on myeloid cells 1 (TREM1). Six biomarkers showed promising results: OSM, SC, eNAMPT, nCD64, TREM1, and CPa9-HNE. Variable positive signals were found for human neutrophil peptide 1-3, LL-37, S100A12, and neutrophil gelatinase-associated lipocalin. No predictive ability was found for the remaining markers. Sharing a neutrophil compartment did not indicate similar behavior.

Conclusion

Advances in the last decade began to unveil the untapped potential of the readily accessible blood neutrophil-expressed biomarkers, especially nCD64, TREM1, and CPa9-HNE. Current evidence suggests that future research should focus on well-defined subpopulations instead of a one-size-fits-all biomarker.

Registration

https://osf.io/kes9a.

Fighting Fire with Fire: Exosomes and Acute Pancreatitis-Associated Acute Lung Injury

Acute pancreatitis (AP) is a prevalent clinical condition of the digestive system, with a growing frequency each year. Approximately 20% of patients suffer from severe acute pancreatitis (SAP) with local consequences and multi-organ failure, putting a significant strain on patients' health insurance. According to reports, the lungs are particularly susceptible to SAP. Acute respiratory distress syndrome, a severe type of acute lung injury (ALI), is the primary cause of mortality among AP patients. Controlling the mortality associated with SAP requires an understanding of the etiology of AP-associated ALI, the discovery of biomarkers for the early detection of ALI, and the identification of potentially effective drug treatments. Exosomes are a class of extracellular vesicles with a diameter of 30-150 nm that are actively released into tissue fluids to mediate biological functions. Exosomes are laden with bioactive cargo, such as lipids, proteins, DNA, and RNA. During the initial stages of AP, acinar cell-derived exosomes suppress forkhead box protein O1 expression, resulting in M1 macrophage polarization. Similarly, macrophage-derived exosomes activate inflammatory pathways within endothelium or epithelial cells, promoting an inflammatory cascade response. On the other hand, a part of exosome cargo performs tissue repair and anti-inflammatory actions and inhibits the cytokine storm during AP. Other reviews have detailed the function of exosomes in the development of AP, chronic pancreatitis, and autoimmune pancreatitis. The discoveries involving exosomes at the intersection of AP and acute lung injury (ALI) are reviewed here. Furthermore, we discuss the therapeutic potential of exosomes in AP and associated ALI. With the continuous improvement of technological tools, the research on exosomes has gradually shifted from basic to clinical applications. Several exosome-specific non-coding RNAs and proteins can be used as novel molecular markers to assist in the diagnosis and prognosis of AP and associated ALI.

Neutrophils in Intestinal Inflammation: What We Know and What We Could Expect for the Near Future

Neutrophils are short-lived cells that play a crucial role in inflammation. As in other tissues, these polymorphonuclear phagocytes are involved in the intestinal inflammatory response, on the one hand, contributing to the activation and recruitment of other immune cells, but on the other hand, facilitating intestinal mucosa repair by releasing mediators that aid in the resolution of inflammation. Even though these responses are helpful in physiological conditions, excessive recruitment of activated neutrophils in the gut correlates with increased mucosal damage and severe symptoms in patients with inflammatory bowel disease (IBD) and pre-clinical models of colitis. Thus, there is growing interest in controlling their biology to generate novel therapeutic approaches capable of reducing exacerbated intestinal inflammation. However, the beneficial and harmful effects of neutrophils on intestinal inflammation are still controversial. With this review, we summarise and discuss the most updated literature showing how neutrophils (and neutrophil extracellular traps) contribute to developing and resolving intestinal inflammation and their putative use as therapeutic targets.

Serological Biomarkers of Extracellular Matrix Turnover and Neutrophil Activity Are Associated with Long-Term Use of Vedolizumab in Patients with Crohn's Disease

Crohn’s disease (CD) is a relapsing-remitting inflammatory disease of the gastrointestinal (GI) tract characterized by increased extracellular matrix (ECM) remodeling. The introduction of the α4β7-integrin inhibitor vedolizumab (VEDO) has improved disease management, although there is a high rate of primary non-response in patients with CD. We studied whether ECM biomarkers of neutrophil activity and mucosal damage could predict long-term response to VEDO in patients with CD. Serum levels of human neutrophil elastase (HNE)-derived fragments of calprotectin (CPa9-HNE), and matrix metalloproteinase (MMP)-derived fragments of type I (C1M), III (C3M), IV (C4M), and VI (C6Ma3) collagen, type III collagen formation (PRO-C3), basement membrane turnover (PRO-C4) and T-cell activity (C4G), were measured using protein fingerprint assays in patients with CD (n = 32) before VEDO therapy. Long-term response was defined as VEDO treatment of at least 12 months. CPa9-HNE was significantly increased at baseline in non-responders compared with responders (p < 0.05). C1M, C3M, C4M, C6Ma3, and PRO-C4 were also significantly increased at baseline in non-responders compared with responders (all p < 0.05). All biomarkers were associated with response to VEDO (all p < 0.05). To conclude, baseline levels of serum biomarkers for neutrophil activity and mucosal damage are linked to the pathology of CD, and are associated with long-term use of VEDO in patients with CD. Therefore, these biomarkers warrant further validation and could aid in therapeutic decision-making concerning vedolizumab therapy.