Brain natriuretic peptide (BNP) was originally isolated from pig brain by Japanese scholars. It is mainly synthesized and secreted by cardiac myocytes and belongs to the natriuretic peptide (NP) family (including atrial natriuretic peptide-ANP, C-type natriuretic peptide-CNP, etc.). It initially exists as pro-BNP precursor containing 134 amino acids, and under the action of enzymes, it is cleaved into inactive NT-proBNP containing 76 amino acids and physiologically active BNP containing 32 amino acids. BNP is mainly degraded in the large blood vessels and other parts of the body, while NT-proBNP is mainly excreted by the kidneys, and the measurement of plasma BNP or NT-proBNP levels can provide an indication of heart failure.
BNP and NT-proBNP are different shears of the same peptide, and levels of both are indicators of changes in cardiac function and can be used to assist in the diagnosis of heart failure. What is the connection and difference between BNP and NT-proBNP?
The molecular structures are different:
BNP is a 32 peptide that binds to the natriuretic peptide receptor to exert its biologically active effects. The length of the NT-proBNP peptide chain is the straight-chain structure of a 76 peptide, an inactive amino acid fragment.
Metabolic pathway:
BNP is cleared mainly by binding to the natriuretic peptide clearance receptor, which is degraded, and only a small amount of BNP is cleared by the kidneys. While the kidney is the only pathway for NT-proBNP clearance, abnormal renal function has a significant impact on NT-proBNP metabolism.
Half-life:
BNP has a half-life of 22 minutes and NT-proBNP has a half-life of 120 minutes. NT-proBNP is relatively more stable in vitro and is more convenient to test.
Diagnostic Threshold for Heart Failure:
BNP<100pg the="" possibility="" of="" heart="" failure="" is="" very="" small.="" bnp="">500ng/L, the possibility of heart failure is very high. Chronic heart failure can generally be ruled out with NT-proBNP below 125ng/L. NT-proBNP diagnosis of acute heart failure is influenced by age and renal function. Patients under 50 years of age are higher than 450ng/L, over 50 years of age are higher than 900ng/L, and over 75 years of age should be higher than 1,800ng/L.
In 2022, the Cardiovascular Expert Committee of the Chinese Physicians Association's Laboratory Physicians Branch issued the "Chinese Expert Consensus on Laboratory Testing and Clinical Application of B-Type Natriuretic Peptide and N-terminal B-Type Natriuretic Peptide Precursors," which recommended the use of NT-proBNP/BNP for the full management of patients with heart failure.
Patients with stage A and stage B heart failure should be screened early for BNP/NT-proBNP and intervene accordingly in patients with BNP > 35 ng/L or NT-proBNP > 125 ng/L to help prevent and delay the onset of heart failure (recommended);
Patients hospitalized with heart failure should have BNP/NT-proBNP testing at admission, discharge, and change in condition (recommended);
In patients with heart failure, BNP/NT-proBNP should be measured every 2-4 weeks after discharge from the hospital, and then every 2-3 months after stabilization of the disease (recommended) [1].
Three points of BNP and NT-proBNP testing
Pain points of BNP and NT-proBNP testing
BNP and NT-proBNP exist in various forms in the human body, and how to specifically recognize and detect the target substances is another technical difficulty. The development of highly specific antibodies or enzyme conjugates is needed to ensure the accuracy and reliability of detection results.
BNP and NT-proBNP have low concentrations, so the assay needs to be highly sensitive and able to detect low concentrations of the target substances. This requires the use of highly sensitive detection technologies and methods such as chemiluminescence, fluorescence, and mass spectrometry.
In some cases, other substances may cross-react with BNP or NT-proBNP, resulting in biased test results. Therefore, there is a need to develop assays with high specificity to minimize the effects of cross-reactivity.
Since the detection of BNP and NT-proBNP involves multiple steps, such as sample processing, incubation, washing, and detection, there is a need to develop highly automated detection systems to improve detection efficiency and accuracy.
Diagreat R&D technology upgraded again, fully solving the pain points of BNP and NT-proBNP detection
Higher sensitivity and specificity - Diagreat Biotech performed multi-stage affinity immunopurification of goat serum immunized against full-length BNP to obtain high-affinity goat polyantibodies targeting BNP 15-23aa, which together with human-mouse chimeric antibodies of 6-14aa can achieve extremely high sensitivity with LoD<1pg/mL, and extremely high specificity without fear of HAMA.
Functional validation of BNP antibodies
High-quality craftsmanship, no fear of any verification - with a well-known imported brand performance verification comparison, correlation R2 = 0.9878
NT-proBNP correlation analysis
Fully automated chemiluminescence immunoassay platform - no manual operation, reducing the number of steps to ensure the efficiency and accuracy of the test.
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