Researchers developed three new immunoassays that can individually measure the three molecular forms of atrial natriuretic peptide (ANP) in blood, revealing that β-ANP levels drop significantly during heart failure treatment and may serve as a distinct biomarker.
3 molecular forms of ANPFor the first time, all three endogenous forms of atrial natriuretic peptide can be individually quantified in plasma using newly developed immunoassays.
What the researchers found
Three chemiluminescent enzyme immunoassays (CLEIAs) were developed using a novel PEGylation technique to reduce background noise, enabling accurate individual measurement of α-ANP, β-ANP, and proANP directly in plasma.
In patients with acute decompensated heart failure, β-ANP levels showed marked decreases during treatment, while proANP levels decreased only moderately. The ratio of β-ANP to total ANP was significantly lower at discharge compared to admission, whereas α-ANP and proANP ratios remained stable. These distinct patterns suggest β-ANP and proANP may offer complementary biomarker information beyond what BNP alone provides.
Why it matters
Current heart failure diagnosis relies heavily on BNP-based blood tests, but ANP — another cardiac hormone — exists in multiple forms that may behave differently during disease. Having tools to measure each ANP form separately opens a new window into heart failure monitoring and could eventually lead to more nuanced diagnostic and treatment approaches.
How the study worked
The researchers designed three plate-based chemiluminescent enzyme immunoassays, each targeting a different measurement: total ANP (sum of all three forms), β-ANP alone, and proANP alone. They added a single-step PEGylation modification to the antibody-binding step to minimize background signals. The assays were validated for sensitivity, specificity, reproducibility, and accuracy, and then applied to plasma samples from patients with acute decompensated heart failure collected during the course of treatment.
What this study cannot tell us
The study focused on developing and validating the assay technology, so the clinical patient data shown is preliminary and the sample size is not clearly reported. The research was conducted in a specific population of acute decompensated heart failure patients, and it remains unclear how these assays would perform across different types and stages of heart failure. Long-term clinical utility and comparison with existing BNP assays in larger trials have not yet been established.
How to read the evidence
This is an assay development and validation study with preliminary clinical data from heart failure patients. While the technical validation appears rigorous, the clinical findings are observational and the sample size is not clearly defined, placing this at a moderate evidence level for clinical applicability.
When this study was published
Published in 2016, this study is nearly a decade old. The immunoassay technology described may have been further developed or adopted since publication, and the clinical landscape for cardiac biomarkers has continued to evolve.
The bigger picture
Heart failure affects millions of people worldwide, and better biomarkers could improve how doctors monitor disease severity and treatment response. While BNP is the current gold standard, the ability to separately track multiple forms of ANP could add a new layer of diagnostic precision. This work lays the technical groundwork for future clinical studies to determine whether ANP-form profiling improves patient outcomes.
Questions still open
- Could routine measurement of individual ANP forms improve heart failure treatment decisions compared to BNP testing alone?
- Do the ratios of ANP molecular forms differ across various types of heart failure (chronic vs. acute, systolic vs. diastolic)?
- Can β-ANP levels predict rehospitalization or other outcomes after heart failure discharge?
Common questions
What is the difference between ANP and BNP in heart failure testing?
Why is it important to measure each form of ANP separately?
Read the original research
Novel Chemiluminescent Enzyme Immunoassays for Individual Quantification of 3 Endogenous Molecular Forms of Atrial Natriuretic Peptide in Human Plasma.
The journal of applied laboratory medicine, 1(1), 47-59
Citation
Nagai-Okatani, Chiaki; Kangawa, Kenji; Takashio, Seiji; Takahama, Hiroyuki; Hayashi, Tomohiro; Anzai, Toshihisa; Minamino, Naoto. (2016). Novel Chemiluminescent Enzyme Immunoassays for Individual Quantification of 3 Endogenous Molecular Forms of Atrial Natriuretic Peptide in Human Plasma.. The journal of applied laboratory medicine, 1(1), 47-59. https://doi.org/10.1373/jalm.2016.020230