EDN2 and ischemia: Endothelin (ET) has four isomers, ET-1, ET-2, ET-3, and ET-4, of which ET-1 is the most biologically active, with strong vasoconstrictive, positive inotropic effects, leading to pro-vascular smooth muscle cell division and proliferation and aggravation of ischemia in organs (Davenport et al., 2016).