Interstitial fibrosis is the common pathophysiological mechanism that leads to end organ failure of the both the heart and the kidney. Fibrosis is characterized by an excessive accumulation of myofibroblast-derived extracellular matrix. Peritubular capillary rarefaction precedes renal fibrosis and is secondary to the loss of capillary pericytes to the interstitium. Endothelial-derived C-type natriuretic peptide (CNP) has been demonstrated to have cGMP dependent anti-fibrotic properties most likely due to the interference with pro-fibrotic TGF-β signaling and may counteract the loss of the capillary pericytes. However, natriuretic peptides like CNP are rapidly degraded by neutral endopeptidase (NEP). In a unilateral urether obstruction (UUO) mouse model for kidney fibrosis we assessed the anti-fibrotic effects of Sol-1, a new orally-active compound (Solvay) that inhibits both neutral endopeptidase and endothelin.