Hemodynamic aberrance in cirrhosis triggers activation of sympathetic tone and the renin-angiotensin-aldosterone system, leading to ischemia on kidney function [41]; β-adrenergic signaling blockade relieves the sympathetic tone and reduces serum renin level, consequently tempering resistance of renal blood flow and protecting against renal injury in cirrhotic patients [42,43]. The gene discussed is REN; the disease is ischemia.