NAMPT and obesity due to melanocortin 4 receptor deficiency: Vascular effects are both chronic and acute (see Figure 5): chronic exposure to high visfatin concentrations—such as in obesity and in type 2 diabetes mellitus—promotes endothelial dysfunction, angiogenesis and atherosclerotic plaque instabilization, whereas acute visfatin administration stimulates eNOS expression and activity in endothelial cells [309] and directly protects cardiomyocytes against the detrimental effects of acute ischemia-reperfusion injury [311].