Background and aims: Predicting the treatment outcomes of biological therapies is an unmet need in Crohn's Disease. In this study, we explored the potential of serum neutrophil-related biomarkers to predict infliximab therapeutic results and disease progression in Crohn's Disease patients, over a 2-year period, in a real-world setting. Methods: The study included 100 asymptomatic Crohn's Disease patients in the IFX maintenance phase from the prospective, observational, multicenter DIRECT study. Patients were categorized according to a composite outcome reflecting progression that included surgery, hospitalizations, new fistulae, abscess or stricture, and drug treatment escalation. Serum neutrophil elastase, lipocalin-2, lactoferrin, and resistin (non-neutrophil control) were analyzed via multiplex magnetic bead assays at multiple touchpoints. Fecal calprotectin was assessed by ELISA. Results: Over up to 2 years of follow-up, serum biomarkers did not differentiate between the composite outcome groups, whereas fecal calprotectin was significantly higher in patients with worse outcomes. During the infliximab maintenance phase, there was a significant, sustained reduction of neutrophil elastase (p < 0.001), lipocalin-2 (p < 0.001), and lactoferrin (p < 0.001), but not of resistin, despite stable neutrophil levels. Correlations between NE and NGAL levels were strong (Pearson correlations 0.75-0.85); all other correlations were of small magnitude. Conclusion: Our real-world data do not support using serum neutrophil elastase, lipocalin-2, or lactoferrin concentrations as predictors of treatment outcomes or disease evolution in infliximab -treated Crohn's Disease patients. On the other hand, the sustained decrease in biomarkers over time suggests that neutrophil stabilization might be an additional infliximab mechanism of action.

BACKGROUND AND AIMS:Effective management of inflammatory bowel disease (IBD) relies on a comprehensive understanding of infliximab (IFX) pharmacokinetics (PK). This study's primary goal was to develop a robust PK model, identifying key covariates influencing IFX clearance (CL), while concurrently evaluating the risk of disease progression during the maintenance phase of IBD treatment. METHODS:The multicenter, prospective, real-world DIRECT study was conducted in several care centers, which included 369 IBD patients in the maintenance phase of IFX therapy. A two-compartment population PK model was used to determine IFX CL and covariates. Logistic and Cox regressions were applied to elucidate the associations between disease progression and covariates embedded in the PK model. RESULTS:The PK model included the contributions of weight, albumin, antidrug antibody (ADA), and fecal calprotectin (FC). On average, higher ADA, FC concentration and weight, and lower albumin concentration resulted in higher IFX CL. In the multivariate regression analyses, FC levels influenced the odds of disease progression in the majority of its definitions, when adjusted for several confounding factors. Additionally, alongside FC, both IFX and CL demonstrated a significant impact on the temporal aspect of disease progression. CONCLUSION:In this 2-year real-world study, readily available clinical covariates, notably FC, significantly impacted IFX availability in IBD patients. We demonstrated that subclinical active inflammation, as mirrored by FC or CRP, substantially influenced IFX clearance. Importantly, FC emerged as a pivotal determinant, not only of IFX pharmacokinetics but also of disease progression. These findings underscore the need to integrate FC into forthcoming IFX pharmacokinetic models, amplifying its clinical significance.

Abstract Background Pancreatic exocrine insufficiency (PEI) can be defined as an insufficient secretion of pancreatic enzymes and bicarbonate to maintain a normal digestion (1). PEI is associated to fat malabsorption, weight loss and malnutrition-related complications. Due to its important role in the digestive process, as a proteolytic enzyme and the high stability of the enzyme during intestinal transit, fecal pancreatic elastase (fPELA) is an ideal biomarker for the assessment of pancreatic function in patients suffering from PEI. The aim of this work was to develop and optimize a new rapid test for the quantification of fPELA. Methods A quantitative lateral flow assay was designed for the selective measurement of elastase antigen concentrations from stool extracts. The BÜHLMANN Quantum Blue® fPELA is a sandwich immunoassay. A monoclonal detection antibody is conjugated to gold nanoparticles. Elastase present in the sample binds to this gold conjugate. A polyclonal capture antibody, highly specific for elastase, is immobilized on the analytical membrane and captures the complex of elastase bound to the anti-elastase gold conjugate, resulting in a coloring of the test line. The remaining free anti-elastase gold conjugate binds to the control line. The signal intensities of the test line and the control line are measured quantitatively by the Quantum Blue® Reader. Pancreatic elastase is quantified in extracts of human stool samples collected with the BÜHLMANN CALEX® Cap device. Several analytical studies, such as sensitivity, linearity, High Dose Hook Effect (HDHE), were performed during optimization phase to assess the performance of the assay. Moreover, a method comparison with the commercially available high throughput turbidimetric BÜHLMANN fPELA® turbo assay was also performed. Results Both analytical and clinical performance were evaluated. Preliminary results of the assay performance were obtained during the optimization phase. Analytical sensitivity was determined as 12.8 µg/g LoB, 16.6 µg/g LoD and 17.2 µg/g LoQ. The linearity evaluation revealed a linear range of 10 to 472 µg/g. No HDHE was observed in native samples up to 4000 µg/g. Method comparison of the new lateral flow assay with BÜHLMANN fPELA® turbo assay, with 80 clinical samples, revealed good analytical agreement with a slope of 1.04 (Passing-Bablok) and a bias at cutoff (200 µg/g) of 5.6%. Relative bias (Bland-Altman) of the two assays was 6.9%. Considering the turbidimetric assay as the reference method, the sensitivity and specificity were 92% and 83%, respectively. Conclusion The newly developed quantitative lateral flow assay, BÜHLMANN Quantum Blue® fPELA, is an accurate, non-invasive and rapid test to determine fPELA levels in fecal extracts. The lateral flow assay is an attractive alternative to ELISA with a turn-around time of only 15 minutes enabling patients’ management in a more patient near clinical environment.

Background Calprotectin is a major granulocyte and monocyte alarmin protein. It can natively occur as dimeric and tetrameric complex of Mrp-8 and Mrp-14. Although, serum calprotectin is emerging as an important biomarker for rheumatoid arthritis and juvenile idiopathic arthritis, fecal calprotectin is already established as the gold standard for diagnostics and monitoring of inflammatory bowel diseases. However, standardization of fecal calprotectin assays differs significantly among providers leading to varying clinical cut-offs. A suspected reason is that calprotectin’s oligomeric states can generate different quantitative results. Yet trapping calprotectin in a distinct oligomeric state is challenging. Objectives The aim of this work was to produce pure calprotectin as calibrator material with a controllable oligomeric state. Methods The oligomeric state of a recombinant fusion protein between Mrp8 and Mrp14 that expressed solubly in E. coli was assessed by size-exclusion chromatography. Direct comparison to native calprotectin regarding antibody affinities were measured and its use as calibrator material in various immunoassay formats was tested. Results The fusion protein was purified as a calprotectin dimer mimic. Calcium addition could successfully transform calprotectin dimer into a calprotectin tetramer. Affinities to monoclonal and polyclonal calprotectin antibodies were comparable to native calprotectin. Spiking of different concentrations of recombinant calprotectin showed linear correlations in ELISA and turbidimetric assays. A perfect correlation (slope=1.009; R2=0.999) was shown when measuring 23 human serum samples based on native and recombinant calprotectin calibrators with a turbidimetric assay. Conclusion The recombinant protein can be purified in large quantities in defined oligomeric states and it shows immunological properties comparable to native calprotectin. Recombinant calprotectin presents as a promising tool to overcome the prevalent fecal calprotectin standardization problem and prevent future standardization discrepancies for serum calprotectin. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests Alexander Ohmann Employee of: Author is employee of BÜHLMANN Laboratories AG, Dmitrii Guschin Employee of: Author is employee of BÜHLMANN Laboratories AG, Joana Afonso Employee of: Author is employee of BÜHLMANN Laboratories AG, Peter Spies Shareholder of: Novartis, Employee of: Novartis until 1999, Daniela Tobler Employee of: I was employed in the past by Novartis. However, I am currently only employed by FHNW., Thomas Villiger Shareholder of: Yes, but only a few shares (I worked once for Novartis and Biogen…), Speakers bureau: Yes, but not for this project, Paid instructor for: Yes, but not for this project, Consultant of: Yes, but not for this project, Grant/research support from: Yes, but not for this project, Employee of: I was employed in the past by Merck, Novartis and Biogen. However, I am currently only employed by FHNW., Dominik Meinel Shareholder of: Roche shares, Employee of: regular employee at Roche 2017-2020, Christian-Benedikt Gerhold Employee of: Author is employee of BÜHLMANN Laboratories AG.

Abstract Background Patients suffering from inflammatory bowel disease can be treated with the biologics adalimumab (ADL) or infliximab (IFX). Previous studies demonstrated the usefulness of therapeutic drug monitoring (TDM) to adjust the patient’s biologic concentration individually. Commercially available rapid assays support laboratories in the fast and easy detection of ADL and IFX concentrations but the assays’ dependency on serum as analyte matrix is a general hindrance for TDM, as serum preparation from whole blood is time-consuming and requires laboratory equipment. Patients and clinicians would thus benefit from rapid point-of-care (POC) and easy to use assays that are independent of laboratory equipment. The objective of this project was to expand existing serum lateral flow assays for the analysis of ADL or IFX in capillary blood and investigate potential interactions resulting from the blood matrix. Methods ADL and IFX lateral flow serum kits were optimized in such a way that both, capillary blood and EDTA whole blood can be used as analyte matrix by using disposable capillaries for blood collection and for its transfer into dropper bottles that are prefilled with chase buffer. To measure ADL or IFX levels with a POC lateral flow test cassette reader (BÜHLMANN Quantum Blue® Reader) the mixture is then applied on an ADL or IFX lateral flow test cassette. Matrix agreement studies were performed to compare spiked EDTA whole blood and capillary blood samples with serum as reference. Additionally, spiked EDTA whole blood samples were treated to obtain three abnormal blood conditions: Icteric, hemolytic and lipemic blood. Bias in results exceeding 30% relative difference to the untreated sample was considered as an interference. Results Spiked blood samples showed good agreement with reference serum samples. A bias of less than 15% at the clinical decision points for ADL (5 µg/mL and 12 µg/mL) and IFX (3 µg/mL and 7 µg/mL) was revealed. Observed relative differences between all tested abnormal blood conditions ranged between -20% and +26% for IFX and -16% and +5% for ADL. Conclusion Two POC assays for the determination of ADL or IFX in capillary blood or EDTA whole blood samples were successfully developed and can be used by healthcare professionals with time to results of only 15 minutes and without the need for additional laboratory equipment. No systematic interferences were detected with treated EDTA whole blood samples, which could appear when using blood as analyte matrix. The excellent agreement to serum trough levels shows that the POC adalimumab/infliximab capillary blood assays are ideal for therapeutic drug monitoring analysis at a clinician’s office or an infusion site.

Background Serum calprotectin (sCAL) is a promising biomarker to detect the inflammatory status of patients in rheumatoid arthritis, juvenile idiopathic arthritis and systemic onset juvenile idiopathic arthritis diseases. Serum calprotectin can be a useful tool to monitor disease activity and predict treatment response in these patients. Objectives The aim of this work was to evaluate the analytical performance of a new sCAL turbidimetric assay, a high throughput test on clinical chemistry analyzers, to determine calprotectin levels in serum. Methods CLSI guidelines (CLSI C28-A3, EP05-A3, EP07-A3, and EP09-A3) were used to establish sCAL turbidimetric assay characteristics.111 samples were measured with 3 lots over 3 days and compared to another commercially available assay. Results The assay presented an analytical measuring range from 0.23 to 15 µg/mL, extended to 225 µg/mL with an additional dilution in an automated rerun on a clinical chemistry analyzer. Reference limits of 1.77 and 1.10 µg/mL were obtained with 160 self-declared healthy adults (m/w) aged 18 to 83 years when sampled either in native tube or tube with gel separator and processed within 3.4 hours after collection respectively. The method is precise, reliable and suitable for routine use, with a within-laboratory precision up to 5.1% and a reproducibility up to 11.1%. No interference was shown with tested concentrations of oral and injectable pharmaceuticals. Hemolyzed samples are not recommended. A method comparison with another commercial assay presented a good agreement with a bias of 2.45% (Bland-Altman) and a slope of 1.16 (Passing Bablok). Conclusion The new sCAL turbidimetric assay is a high throughput quantitative method performed on clinical chemistry analyzers to reliably and precisely assess the inflammatory status of patients. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests Anna Melone Employee of: Author is employee of BÜHLMANN Laboratories AG, Dominik Vogt Employee of: Author is employee of BÜHLMANN Laboratories AG, Alexander Ohmann Employee of: Author is employee of BÜHLMANN Laboratories AG, Joana Afonso Employee of: Author is employee of BÜHLMANN Laboratories AG, Clara Moniz Employee of: Author is employee of BÜHLMANN Laboratories AG, Dmitrii Guschin Employee of: Author is employee of BÜHLMANN Laboratories AG, Christian-Benedikt Gerhold Employee of: Author is employee of BÜHLMANN Laboratories AG, Thomas Schuster Employee of: Author is employee of BÜHLMANN Laboratories AG.

BackgroundThe emergence of new treatments the inflammatory bowel diseases (IBD) raised questions regarding the role of older agents, namely thiopurines.AimsTo clarify the benefits of combination treatment with thiopurines on Crohn's disease (CD) patients in the maintenance phase of infliximab.MethodsIn this analysis of the 2-year prospective multicentric DIRECT study, patients were assessed in terms of clinical activity, faecal calprotectin (FC), C-reactive protein (CRP), and infliximab pharmacokinetics. A composite outcome based on clinical- and drug-related items was used to define treatment failure.ResultsThe study included 172 patients; of these, 35.5 % were treated with combination treatment. Overall, 18 % of patients achieved the composite outcome, without statistically significant differences between patients on monotherapy and on combination treatment (21.6% vs 11.5 %, p = 0.098). Median CRP, FC, and infliximab pharmacokinetic parameters were similar in both groups. However, in the sub-analysis by infliximab treatment duration, in patients treated for less than 12 months, the composite outcome was reached in fewer patients in the combination group than in the monotherapy group (7.1% vs 47.1 %, p = 0.021).ConclusionIn CD patients in maintenance treatment with infliximab, combination treatment does not seem to have benefits over infliximab monotherapy beyond 12 months of treatment duration.

Abstract Background Early flare prediction is essential for the timely management of Crohn’s disease (CD) patients, allowing to optimize the available therapeutic toolbox and to decrease the disease burden. We aimed to evaluate the performance of readily available biomarkers (when evaluated at least once or more frequently during follow-up) and to develop risk matrices to predict CD progression. Methods CD patients receiving infliximab (IFX) as maintenance therapy (n=289) were followed up for 24 months; those patients were enrolled in DIRECT, a prospective, multicenter real-world study. Disease progression was evaluated using two composite outcomes incorporating clinical and drug-related factors, the first including also IFX dose and/or frequency adjustments. Univariate and multivariable logistic regressions were used to calculate the odds ratios (OR) and to develop risk matrices. Results The isolated presence of anemia at least once during follow-up was a significant predictor of disease progression (OR 2.436 and 3.396 [p≤0.001] for composite outcomes 1 and 2, respectively), regardless of confounding factors. Levels of C-reactive protein (CRP) above 10.0 mg/L or fecal calprotectin (FC) above 500.0 µg/g, in at least one visit, were also significant predictors, while milder elevations (3.1-10.0 mg/L and 250.1-500.0 µg/g) were only relevant when found in at least two visits (consecutive or not). The risk matrices combining the different non-invasive biomarkers had a good ability to predict CD progression. Indeed, patients simultaneously presenting anemia, CRP>10 mg/dL and FC>500.0 µg/g at least once had a probability of disease progression that ranged between 42 and 63%. Conclusion The combined evaluation of FC, hemoglobin, and CRP in at least one time point and their incorporation into risk matrices seems to be the optimal strategy for CD management, as data from additional visits did not meaningfully influence the predictions and may delay decision-making. This is one of the first studies developing risk matrices to predict the occurrence of composite outcomes in CD patients, providing an easily applicable tool for CD clinical management.

AbstractBackgroundTimely stratification of Crohn's disease (CD) is essential for patients' management. The use of noninvasive accurate biomarkers is key to monitor treatment and to pursue mucosal healing, the ultimate treatment endpoint in CD.ObjectiveWe aimed to evaluate the performance of readily available biomarkers and develop risk matrices to predict CD progression.MethodsData from 289 CD patients receiving infliximab (IFX) maintenance therapy for 2 years was collected; those patients were included in DIRECT, a prospective multicenter observational study. Disease progression was evaluated using two composite outcomes incorporating clinical and drug‐related factors, the first including IFX dose and/or frequency adjustments. Univariate and multivariable logistic regressions were used to calculate the odds ratios (OR) and to develop risk matrices.ResultsThe isolated presence of anemia at least once during follow‐up was a significant predictor of disease progression (OR 2.436 and 3.396 [p ≤ 0.001] for composite outcomes 1 and 2, respectively) regardless of confounding factors. Isolated highly elevated C‐reactive protein (CRP; >10.0 mg/L) and fecal calprotectin (FC; >500.0 μg/g) in at least one visit were also significant predictors, while milder elevations (3.1–10.0 mg/L and 250.1–500.0 μg/g) were only relevant when detected in at least two visits (consecutive or not). The combination of biomarkers in risk matrices had good ability to predict progression; patients simultaneously presenting anemia, highly elevated CRP and FC at least once had 42%–63% probability of achieving the composite outcomes.ConclusionThe combined evaluation of hemoglobin, CRP, and FC in at least one time point and their incorporation into risk matrices seems to be the optimal strategy for CD management, as data from additional visits did not meaningfully influence the predictions and may delay decision‐making.

Aims: Inflammation-driven endothelitis seems to be a hallmark of acute heart failure (AHF) and cardiogenic shock (CS). Endocan, a soluble proteoglycan secreted by the activated endothelium, contributes to inflammation and endothelial dysfunction, but has been scarcely explored in human AHF. We aimed to evaluate serum (S-Endocan) and urinary endocan (U-Endocan) profiles in AHF and CS patients and to correlate them with biomarkers/parameters of inflammation, endothelial activation, cardiovascular dysfunction and prognosis. Methods: Blood and spot urine were collected from patients with AHF (n = 23) or CS (n = 25) at days 1–2 (admission), 3-4 and 5-8 and from controls (blood donors, n = 22) at a single time point. S-Endocan, U-Endocan, serum IL-1β, IL-6, tumour necrosis factor-α (S-TNF-α), intercellular adhesion molecule-1 (S-ICAM-1), vascular cell adhesion molecule-1 (S-VCAM-1) and E-selectin were determined by ELISA or multiplex immunoassays. Serum C-reactive protein (S-CRP), plasma B-type natriuretic peptide (P-BNP) and high-sensitivity troponin I (P-hs-trop I), lactate, urea, creatinine and urinary proteins, as well as prognostic scores (APACHE II, SAPS II) and echocardiographic left ventricular ejection fraction (LVEF) were also evaluated. Results: Admission S-Endocan was higher in both patient groups, with CS presenting greater values than AHF (AHF and CS vs. Controls, p < 0.001; CS vs. AHF, p < 0.01). Admission U-Endocan was only higher in CS patients (p < 0.01 vs. Controls). At admission, S-VCAM-1, S-IL-6 and S-TNF-α were also higher in both patient groups but there were no differences in S-E-selectin and S-IL-1β among the groups, nor in P-BNP, S-CRP or renal function between AHF and CS. Neither endocan nor other endothelial and inflammatory markers were reduced during hospitalization (p > 0.05). S-Endocan positively correlated with S-VCAM-1, S-IL-6, S-CRP, APACHE II and SAPS II scores and was positively associated with P-BNP in multivariate analyses. Admission S-Endocan raised in line with LVEF impairment (p = 0.008 for linear trend). Conclusion: Admission endocan significantly increases across AHF spectrum. The lack of reduction in endothelial and inflammatory markers throughout hospitalization suggests a perpetuation of endothelial dysfunction and inflammation. S-Endocan appears to be a biomarker of endothelitis and a putative therapeutic target in AHF and CS, given its association with LVEF impairment and P-BNP and its positive correlation with prognostic scores.

BACKGROUND AND AIMS: Subclinical intestinal inflammation is common in Crohn's disease (CD). We aimed to explore its impact in the disease progression of infliximab-treated patients and the usefulness of fecal calprotectin (FC) and C-reactive protein (CRP) as surrogate minimally invasive biomarkers. METHODS: The registry-based, prospective, observational, multicenter DIRECT (study to investigate the correlation of fecal calprotectin with serum Drug levels and development of an antI-dRug antibodiEs among adult patients with inflammatory bowel disease reCeiving anti-TNF-alfa treatment or vedoluzimab treatment) study followed infliximab-treated CD patients for 2 years in a tertiary care setting. Persistent inflammation definition was based on FC (>150 mu g/g, >250 mu g/ g, or >350 mu g/g) or serum CRP (>3 mu g/mL) concentrations over 2 consecutive or at least 3 visits. Patients were categorized according to a composite outcome reflecting disease progression that incorporated surgery; hospitalizations; new fistulae, abscess, or stricture; and treatment escalation. RESULTS: Of 322 DIRECT study patients, 180 asymptomatic, infliximab treated on maintenance regimen were included in the analysis. Patients developing the composite endpoint (n = 96) presented higher median levels of FC (205 [interquartile range, 98-515] mu g/g; P = .045) but not of CRP (2.50 [interquartile range, 0.80-6.00] mu g/mL; P = .895). Biomarker-defined persistent subclinical inflammation prevalence ranged from 24% to 81%. Considering FC >250 mu g/g in 2 consecutive visits, prevalence was 50%, odds of achieving the endpoint were increased 3-fold (odds ratio, 2.996 [95% confidence interval, 1.557-5.776]), and time-to-outcome occurrence was significantly lower among subjects with persistent inflammation (median time: 11 months). Both clinical-related and treatment-related components were significantly associated with persistent inflammation. Definitions based on CRP >3 mu g/mL, FC >150 mu g/g, FC >350 mu g/g, double biomarkers (FC >250 mu g/g and/or CRP >3 mu g/mL), or more visits did not improve predictive ability. CONCLUSIONS: Persistent inflammation, defined simply and readily by FC >250 mu g/g over 2 consecutive visits, was associated with a significantly higher risk and shorter time to occurrence of a composite outcome reflecting disease progression in asymptomatic infliximab-treated CD patients.

Therapeutic drug monitoring of inflammatory bowel disease (IBD) patients under anti-TNF therapy is based on trough level determination of the drug. Rapid assays and multiple ELISAs are available that measure anti-TNF biologics. An international standard is required to improve comparability among different assays. Recently, WHO introduced anti-TNF standards for adalimumab (ADL) and infliximab (IFX). A WHO international reference material (IRM) based standardization is crucial for the harmonization of assays available on the market. The aim of the study was to standardize the BÜHLMANN Quantum Blue® ADL and BÜHLMANN Quantum Blue® IFX based on the WHO IRM for ADL and IFX, respectively. A value transfer from the WHO reference material to the internal calibrator sets for both assays was based on a protocol previously described by Blirup-Jensen et al. (Clin Chem Lab Med 2001; 39(11):1110–1122) and by means of a commercially available ELISA. A method comparison of the ELISA and the rapid test was carried out before the value transfer to guarantee comparability of both assays. Additionally, the correlation of the WHO IRM with the currently used calibrator material was determined for ADL. The correlation of the WHO IFX standard (NIBSC 16/170) with the currently used calibrator material was presented recently (Keller et al. 2020, UEGW 2020). Calibration curves were generated with BÜHLMANN ADL calibrators and with calibrators made from WHO IRM for ADL (NIBSC 17/236). Serum samples, covering a concentration range from 1.0 to 35 µg/mL, were analysed with both calibration curves and compared by Bland-Altman and Passing-Bablok analysis. A preliminary value transfer study revealed an relative uncertainty of 12.3% for both drugs. A good comparison of the ADL and IFX rapid test and the ELISA is given: Passing-Bablok correlation coefficient (R) of 0.953 (ADL) and 0.942 (IFX), and a mean bias determined by Bland-Altman of 1.59 µg/mL (ADL) and -0.5 µg/mL (IFX), respectively. The sample values gained with BÜHLMANN calibrators showed an excellent correlation with values gained with the WHO international standard for ADL as calibrator. Passing-Bablok regression analysis revealed a slope of 1.3 and correlation coefficient (R) of 1.0. To the best of our knowledge, the Quantum Blue® ADL and Quantum Blue® IFX, are the first commercially available quantitative lateral flow assays comprising a WHO based standardization. Additionally, it was demonstrated that the current standardizations of Quantum Blue® ADL correlates very well with the WHO international standard for ADL.

We investigated oxidative stress and RAAS biomarkers, as well as their association, in chronic heart failure (CHF) patients on optimized medical therapy, stratified by disease severity or by renal function. Since vitamin D has been shown to attenuate RAAS activation and oxidative stress, we further evaluated the relationship between vitamin D, RAAS and oxidative stress in CHF patients with or without renal impairment. Sixty CHF outpatients were included and stratified by disease severity or by renal function. We quantified urinary hydrogen peroxide, plasma and urinary isoprostanes, plasma total antioxidant status, urinary angiotensinogen (intrarenal RAAS activation biomarker) and plasma angiotensinogen, plasma renin and aldosterone concentration, serum angiotensin-converting enzyme (ACE) activity, plasma angiotensin peptides, and serum total 25-hydroxyvitamin D (S-total 25(OH)D). Severe CHF patients had higher urinary isoprostanes (p = 0.002) and lower S-total 25(OH)D (p = 0.006) compared to mild-to-moderate patients, but no differences were observed for other redox or RAAS biomarkers. Patients with impaired renal function (iRF) had higher urinary angiotensinogen (p = 0.003) and lower S-total 25(OH)D (p = 0.028) compared to those with normal renal function (nRF), while no differences were observed for the remaining RAAS and redox parameters. Several positive correlations between oxidative stress and RAAS biomarkers were detected in iRF patients, while in patients with nRF these correlations were primarily inverse. In CHF-iRF patients, S-25(OD)D was inversely associated with urinary isoprostanes, which in turn were positively associated with plasma angiotensinogen and serum ACE. In conclusion, CHF patients with renal function impairment have increased intrarenal RAAS activation and lower vitamin D values and might benefit from the combination of RAAS blockers with vitamin D and/or antioxidants.

INTRODUCTION:Dipeptidyl peptidase-4 (DPP-4) is a membrane-bound glycoprotein that acts as a receptor but also exists in a soluble form. It has been recognized as a mediator of inflammation and considered a biomarker in inflammatory bowel disease (IBD). METHODS:We evaluated a prospectively recruited cohort, consisting of 101 patients with IBD, using validated clinical indexes; 22 patients with ulcerative colitis (UC) underwent endoscopic evaluation. Fecal DPP-4 (fDPP-4) levels were analyzed and correlated with clinical scores, Mayo endoscopic score (in UC patients), serum DPP-4, C-reactive protein, and fecal calprotectin. Immunohistochemical staining for DPP-4 in intestinal biopsies was also performed. RESULTS:When compared with remitters, median fDPP-4 levels were higher in patients with ileal Crohn's disease (CD) (7,584 [1,464-7,816] vs 2,104 [630-2,676] ng/mL, P = 0.015) and lower in patients with UC exhibiting clinical activity (1,213 [559-1,682] vs 7,814 [2,555-7,985] ng/mL, P < 0.001). Patients with UC presenting endoscopic activity also had lower levels than remitters (939 [559-1,420] vs 7,544 [4,531-7,940] ng/mL, P = 0.006). Fecal DPP-4 discriminated clinical activity from remission with areas under the curve of 0.76 (95% confidence interval [CI] 0.58-0.94, P = 0.015) and 0.80 (95% CI 0.68-0.93, P < 0.001) in CD and UC, respectively; it allowed to differentiate endoscopic activity in patients with UC, with areas under the curve of 0.84 (95% CI 0.63-1.00, P = 0.009). Immunohistochemical analysis revealed higher DPP-4 apical expression in UC remitters, but no statistically significant differences were revealed between patients with ileal CD. DISCUSSION:Our results suggest that fDPP-4 can be used as a biomarker of IBD activity, particularly in UC. The expression profiles in intestinal tissue might represent a functional compartmentalization of DPP-4 expression.

Background: Serum dipeptidyl peptidase 4 (DPP-4) has drawn particular interest as a biomarker in inflammatory bowel disease (IBD), as this protease inactivates several peptides that participate in the inflammatory cascade. Method& Two prospectively recruited cohorts consisting of 195 patients (101 had Crohn's disease [CD] and 94 had ulcerative colitis [UC]) were evaluated using clinical indexes and followed up to assess for treatment escalation. Sixty-eight patients underwent endoscopic evaluation at baseline. In the second cohort of 46 biologically treated patients, treatment response was assessed. Serum DPP-4, C-reactive protein (CRP), and fecal calprotectin levels were quantified at baseline and during follow-up. Results: Median DPP-4 levels were significantly lower in active IBD patients when compared with remitters (CD: 1043 [831-1412] vs 1589 [1255-1956] ng/mL; P < 0.001; UC: 1317 [1058-1718] vs 1798 [1329-2305] ng/mL; P = 0.001) and healthy controls (2175 [1875-3371] ng/mL). In fact, DPP-4 was able to distinguish clinical and endoscopic activity from remission, with areas under the curve (AUC) of 0.81/0.93 (CD) and 0.71/0.79 (UC), along with the need for treatment escalation, with comparable AUCs of 0.79 (CD) and 0.77 (UC). Furthermore, DPP-4 levels were higher in responders to treatment and more pronounced among UC (1467 [1301-1641] vs 1211 [1011-1448] ng/mL; P < 0.001) than CD patients (1385 [1185-1592] vs 1134 [975-1469] ng/mL; P = 0.015). Conclusions: Our results suggest that serum DPP-4 can be used as a noninvasive biomarker of IBD activity and biological treatment response and a predictor of treatment escalation, particularly when combined with other biomarkers.