An immunoluminometric assay for N-terminal pro-brain natriuretic peptide: development of a test for left ventricular dysfunction

Abstract

Measurement of plasma levels of brain natriuretic peptide (BNP) has been used to assess left ventricular dysfunction and prognosis. Levels of the N-terminus of the precursor of BNP (NT-proBNP) have been reported to be elevated to a greater extent than BNP in left ventricular dysfunction. We have devised a non-radioactive sensitive and specific assay for NT-proBNP based on a competitive ligand binding principle. The chemiluminescent label 4-(2-succinimidyloxycarbonylethyl)phenyl-10-methylacridinium 9-carboxylate fluorosulphonate was used to label peptides representing domains in the middle and C-terminal sections of NT-proBNP. Assay of the C-terminal section of NT-proBNP (amino acids 65-76) in patients with proven left ventricular dysfunction [left ventricular wall motion index median 0.9 (range 0.3-1.4)] revealed elevated values [median 639 (386-911) fmol/ml] compared with normal controls [left ventricular wall motion index of 2 in all, NT-proBNP median 159 (120-245) fmol/ml, P<0.001]. Measurement of the middle section of NT-proBNP (amino acids 37-49) was not a discriminating test. It is thus possible to derivatize small peptides with a methyl acridinium label and preserve immunodetection with specific antibodies. Such methodology may allow non-radioactive immunoluminometric assays to be devised.

Increased circulating pro-brain natriuretic peptide (PROBNP) and brain natriuretic peptide (BNP) in patients with cirrhosis. Relation to cardiovascular dysfunction and severity of disease

“…ProBNP has therefore been suggested as an even better marker of heart failure than BNP. [21][22][23][24] A few previous studies have reported increased plasma BNP concentrations in patients with cirrhosis. [15][16][17][18][19][20] The natriuretic peptides are synthesised as pre-prohormones with endocrinologically active C terminal peptides.…”

“…Recently, however, the propeptide of brain natriuretic peptide (proBNP) has been suggested as an even better indicator of early cardiac dysfunction. [21][22][23][24] Until now, no study has assessed concentrations of circulating proBNP in patients with cirrhosis. The present study was therefore undertaken to determine concentrations of circulating proBNP and BNP in patients with cirrhosis.…”

N-Terminal Pro-B–Type Natriuretic Peptide and Long-Term Mortality in Acute Coronary Syndromes

“…Plates were read on a Dynatech MLX Luminometer, with sequential injections of 100 L of 0.1 mol/L nitric acid (with H 2 O 2 ) and then 100 L of NaOH (with cetyl ammonium bromide). 13 The lower limit of detection was 14.4 fmol/mL of unextracted plasma. Within and between assays, coefficients of variation were acceptable at 2.3% and 4.8%, respectively.…”

“…13 IgG from the sera was purified on protein A sepharose columns. The C-terminal-directed antibody (0.5 g in 100 L for each well) was immobilized onto ELISA plates.…”

Improvement in Cardiac Energetics by Perhexiline in Heart Failure Due to Dilated Cardiomyopathy

“…To assess whether these changes occur early and are by inference directly responsible for the subsequent improvement in cardiac function, we used a shortterm (1-month) regimen of perhexiline that typically resulted in plasma perhexiline levels in the low therapeutic range for approximately 2 weeks. Beadle et al Plasma concentrations of NT-proBNP were determined using an immunoluminometric assay (15). Patients who had plasma triglyceride levels >2.5 mmol/l were assumed not to have fasted, and their samples were excluded from analysis of insulin and metabolites.…”