Neutral endopeptidase inhibition with SCH32615 increased plasma atrial and brain natriuretic peptide levels 1.6- to 1.7-fold in both normal and heart-failed sheep, inducing marked natriuresis in HF.
Does neutral endopeptidase inhibition increase atrial and brain natriuretic peptide levels and improve hemodynamics in sheep with pacing-induced heart failure?
Neutral endopeptidase inhibition augments endogenous atrial and brain natriuretic peptide levels and induces significant natriuresis and diuresis in a sheep model of heart failure.
Atrial and brain natriuretic peptide are both circulating hormones subject to degradation by neutral endopeptidase 24.11. Whereas endogenous levels of atrial natriuretic peptide are increased by neutral endopeptidase inhibition in most pathophysiological states, the effect on brain natriuretic peptide and the influence of cardiac status is less clear. To further evaluate the role of neutral endopeptidase 24.11, we directly compared the responses of atrial and brain natriuretic peptide, together with the effects on other vasoactive hormones, haemodynamics and renal indices, to a neutral endopeptidase inhibitor, SCH32615, and a vehicle control in eight conscious sheep before and during pacing-induced heart failure. 2. In normal animals, SCH32615 significantly increased concentrations of plasma atrial natriuretic peptide (22 +/- 5 pmol/l compared with 14 +/- 2 pmol/l in control, 1.6-fold increase) and brain natriuretic peptide (6.5 +/- 1.2 pmol/l compared with 4.1 +/- 0.7 pmol/l in control, 1.6-fold increase), whereas in heart failure, plasma levels of atrial natriuretic peptide (306 +/- 38 pmol/l compared with 187 +/- 25 pmol/l in control, 1.6-fold increase) and brain natriuretic peptide (93 +/- 11 pmol/l compared with 55 +/- 9 pmol/l in control, 1.7-fold increase) were elevated to a significantly greater absolute, but proportionately similar, extent. In both normal and heart-failed animals, SCH32615 induced reductions in mean arterial pressure and left atrial pressure and increases in haematocrit, plasma cGMP and endogenous creatinine clearance. However, only in heart failure did neutral endopeptidase inhibition induce a significant and marked natriuresis (> 10-fold increase) and diuresis (4-fold increase), together with suppression of renin activity and haemodynamic effects including decreased peripheral resistance and raised cardiac output. 3. In conclusion, neutral endopeptidase inhibition increases plasma concentrations of atrial and brain natriuretic peptide to a proportionately similar extent in both normal and heart-failed sheep. The striking natriuresis and diuresis and additional haemodynamic effects demonstrated in sheep with heart failure, where natriuretic peptide levels are elevated compared with normal sheep, supports the concept that neutral endopeptidase inhibition augments endogenous atrial and brain natriuretic peptide.
Rademaker et al. (Sun,) conducted a other in Heart failure (n=8). SCH32615 (neutral endopeptidase inhibitor) vs. Vehicle control was evaluated on Plasma concentrations of atrial and brain natriuretic peptide, haemodynamics, and renal indices. Neutral endopeptidase inhibition with SCH32615 increased plasma atrial and brain natriuretic peptide levels 1.6- to 1.7-fold in both normal and heart-failed sheep, inducing marked natriuresis in HF.