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 O(2)(-) (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 ischernia, 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.