SMAD3 and Ureteral obstruction: In the present study, we evaluated the role of endogenous Vasohibn‐1 VASH‐1 in regulating tubulointerstitial alterations induced by unilateral ureteral obstruction (UUO), and assessed its regulatory role on fibrogenesis and the activation of TGF‐beta/Smad3 signaling in renal fibroblasts.