With respect to oxidative stress, Totan and coworkers showed the presence of increased Endothelin-1 (ET-1) and reduced Nitric Oxide (NO) plasmatic levels in AMD, suggesting an imbalance between vasoconstrictor and vasodilator agents, possibly reflecting either an endothelial dysfunction in AMD pathogenesis or a role of vasoconstriction in exudative AMD (Totan et al., 2015). Here, EDN1 is linked to age-related macular degeneration.