Peroxynitrite/Nitric Oxide Balance in Ischemia/Reperfusion Injury‐Nanomedical Approach

Electrochemical nanosensors were used to simultaneously monitor in vitro (a single endothelial cell) and in vivo (vasculature of rat) the concentrations of NO (vasorelaxant), cytotoxic O₂⁻ (oxidative stress) and ONOO− (nitroxidative stress). A balance of [NO]/[ONOO−]=(K) was applied as the diagnostic marker of dysfunctional endothelium and cardiovascular disease. In the isolated endothelium of normotensive rats, K= 2.8±0.1 while in hypertensive rats, K=0.4±0.1. During ischemia, K dropped from 7±1 to 1.4±0.2 and further decreased to 0.05±0.01 during reperfusion. The edema and vasoconstriction, indicators of vascular injury, correlated directly with the decrease in K.