The neutral endopeptidase inhibitor, SCH 34826, reduces left ventricular hypertrophy in spontaneously hypertensive rats

SCH 34826, i.e., (S)-N-(N-(2,2[(2,2-dimethyl-1,3-dioxolan-4- yl)methoxy]-2-oxo-1-(phenyl-methyl)ethyl)-phenylalanyl)-beta-alanine, is a potent and selective inhibitor of neutral endopeptidase 24.11 (NEP), an enzyme that degrades the atrial natriuretic peptide (ANP). The effects of SCH 34826 on hypertension and left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHRs) were evaluated following 1 month of treatment by measuring the blood pressure, cardiac weight, and left ventricular fibrosis. Adult SHRs were treated with SCH 34826 at 10, 30, or 100 mg/kg given orally twice daily or with vehicle. The systolic blood pressure (SBP) and heart rate (HR) were recorded weekly by the tail-cuff method. Cardiac structural damage was determined by morphometric analysis. Over the dose range examined, the drug produced no significant changes in either blood pressure or heart rate. Despite the lack of antihypertensive activity, SCH 34826 at 100 mg/kg reduced both the cardiac mass (-10%) and the amount of fibrotic tissue present in the left ventricle (-42%). These data indicate that chronic inhibition of NEP by SCH 34826 interacts with mechanisms underlying myocardial hypertrophy and cardiac remodeling.