REN and hypertensive disorder: As we know, high salt intake increases the delivery of sodium to renal tubules, activates the renin-angiotensin system (RAS), and promotes sodium and water re-absorption from renal tubules, which brings about oxidative stress and proinflammatory cytokines in endothelial cells and then develops to cardiorenal syndrome and hypertension (Weinstock et al., 1996; Selektor and Weber, 2008; Fujita et al., 2012).