Quantitative mass spectral evidence for the absence of circulating brain natriuretic peptide (BNP-32) in severe human heart failure

Adam M. Hawkridge, Denise M. Heublein, H. Robert Bergen, Alessandro Cataliotti, John C. Burnett, David C. Muddiman

Research output: Contribution to journalArticle

215 Scopus citations

Abstract

C-terminal brain (B-type) natriuretic peptide (BNP)-32 is a widely used clinical biomarker for the diagnosis, prognosis, and treatment of heart failure (HF). The 32-aa peptide is synthesized primarily in the atrial and ventricular myocardium and constitutes the mature biologically active form of immature BNP (pro-BNP). There has been mounting evidence that suggests BNP circulates in different structural forms that impact HF diagnosis and in vivo activity. Herein, we have developed and used an immunoaffinity purification assay to isolate endogenous BNP-32 from New York Heart Association class IV patient plasma for subsequent analysis by nano-liquid chromatography (LC) electrospray ionization Fourier transform ion cyclotron resonance (FT-ICR) MS. We have introduced stable isotopelabeled BNP-32 to the assayed plasma to enable quantification of endogenous levels of BNP-32. Unlike the chemically nonspecific point-of-care tests (POCTs) and RIAs used worldwide to quantify BNP-32 from plasma, FT-ICR-MS (unprecedented mass measurement accuracy) coupled with LC (retention time) affords extraordinary molecular specificity, and when combined with the use of internal standards is able to confidently identify and quantify BNP-32. The significance of this work is despite exceedingly high circulating levels of BNP-32 in the New York Heart Association class IV patients as determined by POCTs (>290 fmol/ml) nano-LC-electrospray ionization-FT-ICR-MS data did not reveal any endogenous BNP-32. These results provide molecularly specific evidence for the absence of circulating BNP-32 in advanced-stage HF patients and suggest the existence of altered forms of BNP that are contributing to the POCT values.

Original languageEnglish (US)
Pages (from-to)17442-17447
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume102
Issue number48
DOIs
StatePublished - Nov 29 2005

Keywords

  • Biomarkers
  • Electrospray ionization
  • Fourier transform-ion cyclotron resonance MS
  • Immunoaffinity purification
  • Targeted proteomics

ASJC Scopus subject areas

  • General

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