Background: Here, we report on a head-to-head comparison of the fully-automated Elecsys® Anti-SARS-CoV-2 immunoassay with the EDI TM enzyme linked immunosorbent assays (ELISA) for the detection of SARS-CoV-2 antibodies in human plasma. Methods: SARS-CoV-2 antibodies were measured with the Elecsys® assay and the EDI TM ELISAs (IgM and IgG) in 64 SARS-CoV-2 RT-PCR confirmed COVID-19 patients with serial blood samples (n = 104) collected at different time points from symptom onset. Blood samples from 200 healthy blood donors and 256 intensive care unit (ICU) patients collected before the COVID-19 outbreak were also used. Results: In COVID-19 patients, the percentage of positive results rose with time from symptom onset, peaking to positivity rates after 15-22 days of 100% for the Elecsys® assay, of 94% for the EDI TM IgM-ELISA and of 100% for the EDI TM IgG ELISA. In the 104 blood samples, the agreement between positive/negative classifications of the Elecsys® assay and the EDI TM ELISAs (IgM or IgG) was 90%. The false positivity rates in the healthy blood donors and the ICU patients were < 1% for the Elecsys® assay and < 3% for the EDI TM ELISAs. Conclusions: Our results indicate a high sensitivity and specificity for the Elecsys® assay and an acceptable agreement with the EDI TM ELISAs.

BACKGROUND Soluble suppression of tumorigenicity 2 (sST2) has emerged as a strong prognostic biomarker in patients with heart failure and myocardial infarction. The aim of this study was to evaluate the long-term prognostic value of sST2 in patients with stable coronary artery disease (CAD). METHODS sST2 plasma concentrations were measured in 1345 patients with stable CAD referred for coronary angiography at a single tertiary care center. The primary endpoint was all-cause mortality. RESULTS During a median follow-up time of 9.8 years, 477 (36%) patients died. The median sST2 plasma concentration at baseline was significantly higher among decedents than survivors (21.4 vs 18.5 ng/mL; P &lt; 0.001). In multivariate Cox proportional hazards regression analysis, sST2 was an independent predictor of all-cause mortality (risk ratio 1.16 per 1-SD increase in log-transformed values; 95% CI 1.05–1.29; P = 0.004). In the same multivariate analysis, amino-terminal pro–B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) were also independent predictors, whereas galectin-3 was not. Patients with sST2 in the highest quartile (&gt;24.6 ng/mL) displayed a 2-fold increased risk of death in univariate analysis, which was attenuated but remained significant in a fully adjusted model (risk ratio 1.39; 95% CI 1.10–1.76; P = 0.006). Further analysis showed that the prognostic impact of sST2 was additive to NT-proBNP and hs-cTnT. Using a multibiomarker approach combining these 3 complementary makers, we demonstrated that patients with all 3 biomarkers in the highest quartiles had the poorest outcome. CONCLUSIONS In this cohort of patients with stable CAD, increased sST2 was an independent predictor of long-term all-cause mortality and provided complementary prognostic information to hs-cTnT and NT-proBNP.

Rationale:The neuropeptide catestatin is an endogenous nicotinic cholinergic antagonist that acts as a pleiotropic hormone.Objective: Catestatin shares several functions with angiogenic factors. We therefore reasoned that catestatin induces growth of new blood vessels. Methods and Results:Catestatin induced migration, proliferation, and antiapoptosis in endothelial cells and exerted capillary tube formation in vitro in a Matrigel assay, and such effects were mediated via G protein, mitogen-activated protein kinase, and Akt. Catestatin-induced endothelial cell functions are further mediated by basic fibroblast growth factor, as shown by blockade of effects by a neutralizing fibroblast growth factor antibody. Furthermore, catestatin released basic fibroblast growth factor from endothelial cells and stimulated fibroblast growth factor signaling. In addition to its function on endothelial cells, catestatin also exerted effects on endothelial progenitor cells and vascular smooth muscle cells. In vivo, catestatin induced angiogenesis in the mouse cornea neovascularization assay and increased blood perfusion and number of capillaries in the hindlimb ischemia model. In addition to angiogenesis, catestatin increased density of arterioles/arteries and incorporation of endothelial progenitor cells in the hindlimb ischemia model, indicating induction of arteriogenesis and postnatal vasculogenesis. Conclusion:We conclude that catestatin acts as a novel angiogenic cytokine via a basic fibroblast growth factor-dependent mechanism. (Circ Res. 2010;107:1326-1335.) Key Words: angiogenesis Ⅲ blood vessels Ⅲ endothelium Ⅲ endothelial progenitor cells C hromogranin (Cg)A, the index member of the chromogranin/secretogranin protein family, is the major soluble protein of catecholamine storage vesicles of sympathetic nerve terminals and the adrenal medulla. 1,2 CgA is a proprotein giving rise to biological active peptides like the dysglycemic hormone pancreastatin, 3 the vasodilator vasostatin, 4 and catestatin 5 (CST) ), which inhibits catecholamine release by acting as a nicotinic cholinergic antagonist, resulting in a negative-feedback mechanism. Although plasma CgA is high in human essential (hereditary) hypertension, the plasma concentration of CST is lower in both established cases and in normotensive subjects with a family history of the disease, 6 suggesting a mechanism whereby diminished CST might increase the risk for later development of hypertension. Consistent with the human findings, high blood pressure has been reported in mice after targeted ablation of the Chga gene (Chga knockout), and such high blood pressure can be "rescued" either by replacement with CST or introduction of the human ortholog in the Chga knockout background. 7 Angiogenesis, the growth of new vessels from the preexisting vasculature, is an important process in many physiological conditions including embryonic development and wound healing. However, defects in the regula- Original received February 25, 2010; revision received September 27, 2010;...

Background-Secretoneurin is an abundant neuropeptide of the central, peripheral, and autonomic nervous systems, located in nerve fibers characterized by a close interaction with blood vessels and known to stimulate endothelial cell migration. Methods and Results-We hypothesized that secretoneurin might act as an angiogenic cytokine and tested for these effects in vivo using a mouse cornea neovascularization model and in vitro by assessing capillary tube formation in a matrigel assay. In vivo, secretoneurin-induced neovasculature is characterized by a distinct pattern of arterial and venous vessels of large diameter and length. Immunohistochemical staining for CD-31 revealed endothelial lining of the inner surface of these vessels, and recruitment of ␣-smooth muscle actin-positive perivascular cells suggests vessel maturation. In vitro, secretoneurin-induced capillary tube formation was dose dependent and specific, confirming that effects of secretoneurin occur directly on endothelial cells. Secretoneurin also stimulated proliferation and exerted antiapoptotic effects on endothelial cells and activated intracellular phosphatidylinositol 3Ј kinase/Akt and mitogen-activated protein kinase pathways, as demonstrated by increased phosphorylation of Akt and extracellular signal-regulated kinase. Conclusions-These data show that secretoneurin represents a novel direct angiogenic cytokine and reiterate the coordinated relationship between nervous and vascular systems.

Because increased plasma concentrations of sST2, galectin-3, and GDF-15 are not specific for a distinct disease group, the three biomarkers are not useful for diagnostic purposes. The results of our study are novel with respect to sST2, galectin-3 and GDF-15 as markers of inflammatory diseases and should encourage further studies.

Background: Antibody tests are essential tools to investigate humoral immunity following SARS-CoV-2 infection or vaccination. While first-generation antibody tests have primarily provided qualitative results, accurate seroprevalence studies and tracking of antibody levels over time require highly specific, sensitive and quantitative test setups. Methods: We have developed two quantitative, easy-to-implement SARS-CoV-2 antibody tests, based on the spike receptor binding domain and the nucleocapsid protein. Comprehensive evaluation of antigens from several biotechnological platforms enabled the identification of superior antigen designs for reliable serodiagnostic. Cut-off modelling based on unprecedented large and heterogeneous multicentric validation cohorts allowed us to define optimal thresholds for the tests' broad applications in different aspects of clinical use, such as seroprevalence studies and convalescent plasma donor qualification. Findings: Both developed serotests individually performed similarly-well as fully-automated CE-marked test systems. Our described sensitivity-improved orthogonal test approach assures highest specificity (99.8%); thereby enabling robust serodiagnosis in low-prevalence settings with simple test formats. The inclusion of a calibrator permits accurate quantitative monitoring of antibody concentrations in samples collected at different time points during the acute and convalescent phase of COVID-19 and disclosed antibody level thresholds that correlate well with robust neutralization of authentic SARS-CoV-2 virus. Interpretation: We demonstrate that antigen source and purity strongly impact serotest performance. Comprehensive biotechnology-assisted selection of antigens and in-depth characterisation of the assays allowed us to overcome limitations of simple ELISA-based antibody test formats based on chromometric reporters, to yield comparable assay performance as fully-automated platforms.

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BackgroundComparative proteomics has recently identified afamin, the newest member of the albumin gene family, as a potential biomarker for ovarian cancer. The aim of this study was the analytical and clinical evaluation of a sandwich enzyme-linked immunosorbent assay for the determination of afamin in human plasma.MethodsWe evaluated precision, linearity, and detection limit of the assay, analyte stability and biological variability, determined reference values and quantified afamin concentrations in various diseases.ResultsWithin-run and total coefficients of variation were < 10%. The method was linear across the tested measurement range. Detection limit was 7 mg/L for the assay. The analyte was stable for 24 h at room temperature, for 48 h at 4 °C, and for at least one year at − 20 °C and − 80 °C. The reference change value for healthy individuals was 24%. Age- and sex-independent reference values in healthy blood donors were 45–99 mg/L (median 68 mg/L). In the clinical assay evaluation afamin plasma concentrations were modestly decreased in patients with heart failure. Patients with pneumonia or sepsis exhibited markedly decreased afamin plasma concentrations. However, patients with chronic renal disease or chronic obstructive pulmonary disease showed no difference in afamin plasma concentrations as compared to healthy individuals. Correlation analyses revealed an inverse association between afamin and inflammatory biomarkers.ConclusionsThe afamin assay meets quality specifications for laboratory medicine. The results of the clinical assay evaluation revealed novel insights with respect to afamin as a potential negative acute phase protein and should encourage further studies.