Detection by ELISA of C-terminal proBNP in plasma from cats with cardiomyopathy.
The B-type natriuretic peptide prohormone (proBNP) is enzymatically cleaved into an inactive N-terminal peptide and a biologically active C-terminal peptide with many beneficial cardiorenal effects. The purpose of this study was to develop and test in cats with cardiomyopathy an immunoassay to quantify the concentrations of C-terminal proBNP in feline plasma. An anti-canine proBNP monoclonal antibody (UI-1021) was shown to have adequate binding affinity to proBNP 80-106 for use in a solid-phase immunoassay, and by epitope mapping to bind within positions 84-87 of feline proBNP. UI-1021 was paired with an affinity-purified rabbit polyclonal detection antibody to feline proBNP 100-106, in a sandwich ELISA with feline proBNP 80-106 standard. The linearity and analytical range and sensitivity of the assay were confirmed from 1.4 to 85 pmol/L. Spike recovery averaged 106.5% (95% confidence interval 78-135%). Within run and intra-assay coefficients of variation were <12%. A protease inhibitor mixture preserved proBNP 80-106 immunoreactivity for at least 5 days in plasma. Clinical verification of the ELISA was done using plasma from 13 cats with cardiomyopathy, whose C-terminal proBNP concentrations ranged from 1.7 to 78.8 pmol/L vs. <1.4-1.8 pmol/L in plasma from 18 healthy cats. Concentrations were found to be substantially lower than reported N-terminal proBNP concentrations, and similar to those of human heart failure patients where relative C-terminal BNP deficiencies have been proposed as contributory to the progression of the disease.
Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, USA. Electronic address: psolter@illinois.edu.
Philip F
PF
Solter
Department of Clinical Studies - Philadelphia, School of Veterinary Medicine, University of Pennsylvania, USA.
Mark A
MA
Oyama
Department of Clinical Studies - Philadelphia, School of Veterinary Medicine, University of Pennsylvania, USA.
Maggie C
MC
Machen
Department of Clinical Studies - Philadelphia, School of Veterinary Medicine, University of Pennsylvania, USA.
Dennis J
DJ
Trafny
Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, USA.
D David
DD
Sisson
D000818:Animals; D009202:Cardiomyopathies / Q000097:blood / Q000378:metabolism / Q000662:veterinary*; D002371:Cat Diseases / Q000097:blood / Q000378:metabolism*; D002415:Cats; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood* / Q000378:metabolism
D010446:Peptide Fragments; D020097:Natriuretic Peptide, Brain
B-type natriuretic peptide; Feline cardiomyopathy; Heart failure; Immunoassay; Natriuretic peptides