Comparative measurement of CNP and NT-proCNP in human blood samples: a methodological evaluation

Abstract

BackgroundC-type natriuretic peptide (CNP) has anti-inflammatory, anti-proliferative, and anti-migratory properties. During the past years, CNP has attained an increasing interest by many research groups, especially in the cardiovascular field. Nevertheless, still no reliable data exist on the difference of CNP concentration between serum and plasma samples. Also, the influence of delayed blood sample proceeding is unknown. The aim of this study was to investigate the difference of CNP and NT-proCNP concentrations between serum and plasma samples. In order to identify potential methodological bias, this study should also validate the stability of CNP and NT-proCNP in full blood samples stored at room temperature.FindingsTriplets (serum, plasma, full blood) of fasting blood samples from 12 healthy male individuals were collected. Analysis of CNP and NT-proCNP concentration was performed immediately following sampling, and after 30 minutes or 2 hours of storage at room temperature. Mean serum concentrations at baseline were 0.997 ± 0.379 ng/ml for CNP and 58.5 ± 28.3 pg/ml for NT-proCNP. Furthermore, NT-proCNP concentration did not change significantly during the allotted time and did not differ between serum, plasma, and full blood samples. At baseline, concentrations of CNP were significantly different between samples containing either sodium-citrate or EDTA as a clotting inhibitor (1.933 ± 0.699 ng/ml vs. 0.991 ± 0.489 ng/ml, p = 0.001).ConclusionsCNP and NT-proCNP are stable for at least two hours, even when sample processing is delayed or blood probes are stored at room temperature. NT-proCNP assay demonstrated more consistent and reliable data and should therefore be preferred for usage in clinical applications. Nevertheless, as recommended for ANP and BNP, immunoassays for CNP should also be standardized or harmonized in the future.

Plasma Amino-Terminal Propeptide of C-Type Natriuretic Peptide Concentration in Normal-Weight and Obese Children

“…It is also known that degradation of proCNP in the circulation starts from the carboxyl terminal of the peptide ( 12 ) and N-terminal-directed antibodies against proCNP increase specificity for the propeptide ( 21 ). Thus, NT-proCNP is considered as an accurate target for the measurement of circulating CNP concentration and as a potential biomarker in growth and/or human diseases ( 12 , 21 , 27 ).…”

Clinical Aspects of C-Type Natriuretic Peptide on the Cardiovascular System

“…CNP exhibit several actions on cardiomyocytes such as antiproliferative, pro-apoptotic, anti-fibrotic and anti-hypertrophic effects [18,19]. It also inhibits neointimal restenosis and reduces cardiac ischemia-reperfusion injury and vascular constrictive remodeling [18].…”

“…CNP exhibit several actions on cardiomyocytes such as antiproliferative, pro-apoptotic, anti-fibrotic and anti-hypertrophic effects [18,19]. It also inhibits neointimal restenosis and reduces cardiac ischemia-reperfusion injury and vascular constrictive remodeling [18]. These beneficial effects should be related to the inhibition of cardiac fibroblasts collagen synthesis due to an inhibitory effect on DNA [12,19].…”

N-Terminal pro C-Type Natriuretic Peptide (NTproCNP) and myocardial function in ageing

“…NTproCNP has a longer half-life and is present in the blood at higher concentrations than biologically active CNP. As such, NTproCNP may in fact demonstrate even more consistent data than CNP in terms of clinical application [18]. Furthermore, levels of NTproCNP also show significant correlation with CNP concentrations, as both molecules are released from cells at an equimolar ratio[19].…”