Janice Chew-Harris1, Sarah Appleby2, A Mark Richards3, Richard W Troughton4, Christopher J Pemberton2. 1. Christchurch Heart Institute, University of Otago, Christchurch, New Zealand. Electronic address: janice.chew-harris@otago.ac.nz. 2. Christchurch Heart Institute, University of Otago, Christchurch, New Zealand. 3. Christchurch Heart Institute, University of Otago, Christchurch, New Zealand; Cardiovascular Research Institute, National University of Singapore, Singapore; Department of Cardiology, Canterbury District Health Board, Christchurch, New Zealand. 4. Christchurch Heart Institute, University of Otago, Christchurch, New Zealand; Department of Cardiology, Canterbury District Health Board, Christchurch, New Zealand.
Abstract
BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) is an emerging marker of cardiovascular disease burden. Appropriate assessment of assay performance and reference interval are required to enable interpretation of results to facilitate its clinical application. METHODS: suPAR was measured using the suPARnostic® ELISA in 155 healthy volunteers. Assay performance was assessed for anticoagulant effect, recovery, interference, linearity and cross-reactivity. The identity of immunoreactive suPAR was confirmed by size-exclusion HPLC. To establish anatomical sites of release and uptake, we measured suPAR in regional samples from subjects undergoing cardiac catheterization. RESULTS: The median concentration of suPAR was 2.1 ng/mL (IQR:1.7-2.3) in health. In comparison with EDTA, suPAR measurements were affected by lithium heparin (>10% change) and increased with serum usage. suPAR reactivity also increased in the presence of haemolysis (10 g/L), but was suppressed with urokinase and lipids (4 g/L). In multiple regression analyses, suPAR associated independently with body weight, NT-proBNP and MR-proADM (P = .03) for healthy individuals. Regional plasma sampling showed lower suPAR concentrations in the coronary sinus and renal vein compared with concentrations in femoral arterial samples. Immunoreactive circulating suPAR species had Mr of 10-39 kDa. CONCLUSION: The suPARnostic® assay performs acceptably for a clinical assay but is limited in the presence of high levels of hemolysis, lipids and urokinase. We provide the first evidence for the heart and kidneys as organs of suPAR clearance in humans. Additional investigations are warranted to determine whether there is a need to compare the marker performance of differing circulating forms of suPAR.
BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) is an emerging marker of cardiovascular disease burden. Appropriate assessment of assay performance and reference interval are required to enable interpretation of results to facilitate its clinical application. METHODS:suPAR was measured using the suPARnostic® ELISA in 155 healthy volunteers. Assay performance was assessed for anticoagulant effect, recovery, interference, linearity and cross-reactivity. The identity of immunoreactive suPAR was confirmed by size-exclusion HPLC. To establish anatomical sites of release and uptake, we measured suPAR in regional samples from subjects undergoing cardiac catheterization. RESULTS: The median concentration of suPAR was 2.1 ng/mL (IQR:1.7-2.3) in health. In comparison with EDTA, suPAR measurements were affected by lithium heparin (>10% change) and increased with serum usage. suPAR reactivity also increased in the presence of haemolysis (10 g/L), but was suppressed with urokinase and lipids (4 g/L). In multiple regression analyses, suPAR associated independently with body weight, NT-proBNP and MR-proADM (P = .03) for healthy individuals. Regional plasma sampling showed lower suPAR concentrations in the coronary sinus and renal vein compared with concentrations in femoral arterial samples. Immunoreactive circulating suPAR species had Mr of 10-39 kDa. CONCLUSION: The suPARnostic® assay performs acceptably for a clinical assay but is limited in the presence of high levels of hemolysis, lipids and urokinase. We provide the first evidence for the heart and kidneys as organs of suPAR clearance in humans. Additional investigations are warranted to determine whether there is a need to compare the marker performance of differing circulating forms of suPAR.
Authors: David T Arnold; Fergus W Hamilton; Karen T Elvers; Stuart W Frankland; Natalie Zahan-Evans; Sonia Patole; Andrew Medford; Rahul Bhatnagar; Nicholas A Maskell Journal: Am J Respir Crit Care Med Date: 2020-06-15 Impact factor: 21.405
Authors: Julius Nikorowitsch; Tim Borchardt; Sebastian Appelbaum; Francisco Ojeda; Karl J Lackner; Renate B Schnabel; Stefan Blankenberg; Tanja Zeller; Mahir Karakas Journal: J Am Heart Assoc Date: 2020-04-17 Impact factor: 5.501
Authors: Joseph Dowsett; Maria Didriksen; Jakob Hjorth von Stemann; Margit Hørup Larsen; Lise Wegner Thørner; Erik Sørensen; Christian Erikstrup; Ole Birger Pedersen; Morten Bagge Hansen; Jesper Eugen-Olsen; Karina Banasik; Sisse Rye Ostrowski Journal: Sci Rep Date: 2022-01-31 Impact factor: 4.379