title: B-type natriuretic peptide and its precursor in cardiac venous blood from failing hearts.
abstract: BACKGROUND
  Plasma concentrations of B-type natriuretic peptide (BNP-32) and its precursor (proBNP) are increased in chronic heart failure. Accordingly, BNP-32 and proBNP are both being implemented as clinical markers.
  
  
  OBJECTIVE
  To determine the molar relation of BNP-32 and proBNP in different cardiovascular regions.
  
  
  RESULTS
  Blood samples were obtained from different cardiovascular regions during right heart catheterization in heart failure patients, and from normal subjects. Plasma BNP-32 and proBNP concentrations were measured using sequence-specific radioimmunoassays. Patients with severe left ventricular dysfunction (n=21) displayed increased peripheral plasma concentrations of both BNP-32 (four-fold, P=0.0008) and proBNP (seven-fold, P=0.0002) compared with normal subjects. Moreover, the peripheral concentrations were highly correlated with the corresponding concentrations in the coronary sinus (BNP-32: r=0.97, P<0.0001; proBNP: r=0.94, P<0.0001). Despite comparable peripheral concentrations of BNP-32 and proBNP, the BNP-32 concentration was higher than the proBNP concentration in the coronary sinus (median 126 pmol/l (21-993) vs. 103 pmol/l (16-691), P=0.035).
  
  
  CONCLUSIONS
  The BNP-32 and proBNP concentrations are closely related in venous cardiac blood. The findings suggest an overall constitutive secretion of processed proBNP, i.e. an N-terminal precursor fragment and BNP-32, in chronic heart failure.
authors.affiliation: Cardiac Catheterization Laboratory, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. jpg@dadlnet.dk
authors.forename: Jens Peter
authors.initials: JP
authors.lastname: Goetze
authors.forename: Jens F
authors.initials: JF
authors.lastname: Rehfeld
authors.forename: Regitze
authors.initials: R
authors.lastname: Videbaek
authors.forename: Lennart
authors.initials: L
authors.lastname: Friis-Hansen
authors.forename: Jens
authors.initials: J
authors.lastname: Kastrup
mesh_terms: D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization; D016022:Case-Control Studies; D005260:Female; D006325:Heart Atria / Q000378:metabolism; D006333:Heart Failure / Q000097:blood*; D006352:Heart Ventricles / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D009419:Nerve Tissue Proteins / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011651:Pulmonary Artery / Q000378:metabolism; D012720:Severity of Illness Index; D014682:Vena Cava, Inferior / Q000378:metabolism
chemical_list: D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain