Circulating levels of cardiac natriuretic peptides (ANP and BNP) measured by highly sensitive and specific immunoradiometric assays in normal subjects and in patients with different degrees of heart failure

Abstract

Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels increase in patients with heart failure with the progression of clinical symptoms and with the deterioration of hemodynamics; consequently, assay methods for these peptides may be useful in the follow-up of cardiac patients. Non-competitive immunoradiometric assay (IRMA) methods for ANP or BNP do not generally require preliminary extraction and/or purification of the plasma sample, and so may be more suitable than competitive immunoradiometric assay (RIA) methods for the routine assay of plasma peptide concentrations. We evaluated the analytical characteristics and clinical usefulness of two IRMAs for plasma ANP and BNP, to verify whether these methods may be considered suitable for the follow-up of patients with heart failure. Both methods are based on the solid-phase sandwich IRMA system, which uses two monoclonal antibodies prepared against two sterically remote epitopes of peptide molecule; the first antibody was coated on the beads solid-phase and the second was radiolabeled with 125I. Blood samples were collected from a brachial vein in ice-chilled disposable polypropylene tubes containing aprotinin and EDTA after the patient had rested for at least 20 min in the recumbent position. Plasma samples were immediately separated by centrifugation and stored at -20 C until assay. The IRMA methods showed a better sensitivity and a wider working range sensitivity (about 2 ng/l) than those of RIA methods. Moreover, the normal range found with these methods (ANP = 16.1 +/- 8.6 ng/l, 5.2 +/- 2.8 pmol/l, BNP = 8.6 +/- 8.2 ng/l, 2.5 +/- 2.4 pmol/l) was similar to that generally reported using the most accurate methods, such as the other IRMAs or RIAs, using a preliminary extraction and purification of plasma samples with chromatographic procedures. Our results obtained in patients with different degrees of heart failure indicate that plasma ANP and BNP increase with the progression of clinical symptoms (NYHA class) (ANOVA p < 0.0001). Indeed, circulating levels of ANP (R = -0.701, no. = 86) and BNP (R = -0.745, no. = 55) were significantly (p < 0.0001) and negatively correlated with the left ventricular ejection fraction values. Furthermore, a close curvilinear regression (R = 0.960, no. = 215) was found between ANP and BNP values, because plasma BNP progressively increases more than plasma ANP in patients with different stages of heart failure. In conclusion, IRMA methods are preferable for the measurement of plasma ANP and BNP for experimental studies and routine assay because they are more practicable, sensitive and accurate than RIA procedures. Finally, BNP assay appears to be better than ANP for discriminating between normal subjects and patients with different degrees of heart failure.

Clinical efficacy of dual inhibitor of neprilisin and AT1‑angiotensin receptors LCZ696 (sakubitril/valsartan) in chronic heart failure patients with impaired renal function

“…Благодаря этому концентрация ПНП в плазме крови здоровых людей в 1,5-2 раза выше содержания МНП. В крови пациентов с ХСН, отличаю-щихся повышенной активностью нейрогормональных систем и объемной перегрузкой сердца, уровень обоих НУП возрастает по мере прогрессирования тяжести состояния, и в ряде случаев содержание МНП в связи с его избыточной продукцией кардиомиоцитами ЛЖ может превышать концентрацию ПНП [14][15][16].…”

Plasma adrenomedullin relation with doppler-derived dP/dt in patients with congestive heart failure

“…This method has been reported previously in detail in the literature. 19,20 N-terminal proBNP was evaluated with a fully automated electrochemiluminescent assay (ECLIA) on Elecsys ® 2010 analyzer (Roche Diagnostics, Mannheim, Germany), as recently reported in detail. 21 …”

In-hospital and long-term outcomes of congestive heart failure: Predictive value of B-type and amino-terminal pro-B-type natriuretic peptides and their ratio

“…The physiological actions of ANP are similar to those of BNP, including a reduction in systemic vascular resistance and central venous pressure and an increase in natriuresis (22). The ANP level has been demonstrated to be significant in the prognosis of patients with atrial fibrillation and CHF (23)(24)(25). However, BNP and NT-BNP appear superior to ANP in the diagnosis of HF due to a closer association with echocardiographic evidence of left ventricular dysfunction and a longer half-life.…”