NOS3 and endothelial dysfunction: Defective biosynthesis of NO and facilitated secretion of ROS by uncoupled eNOS, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, xanthine oxidase, lipoxygenase, cyclooxygenase, microsomal P-450 enzymes, and pro-oxidant heme molecules are considered as the molecular mechanisms for endothelial dysfunction [6,35].