NOS2 and myocardial infarction: The depletion of tetrahydrobiopterin (BH4), an important cofactor of NOS, in MI/RI resulted in increased eNOS uncoupling and ROS production, but preischemia administration of liposomal BH4 can reduce the dysfunction of eNOS secondary to BH4 depletion during reperfusion, thus protecting cardiac function [180].