NAMPT and endothelial dysfunction: To address this question, we used mesenteric arteries from both rat and human origin to explore the influence of visfatin on both contractile and vasorelaxant microvascular responses, with special attention to the role played by two enzymes, namely nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, as a superoxide anions-generating enzyme closely associated to endothelial dysfunction [12], [13], and Nampt.