Although HFD induced dyslipidemia in hepatic Nampt deficient mice, oil red O staining showed no lipid deposition, i.e., no atherosclerotic plaque formation, in the aortas of both HC-Nampt-/- and WT mice (Figure 5F), which is totally different with the positive atherosclerotic plaque controls in the aortas of ApoE-/- mice. This evidence concerns the gene APOE and metabolic syndrome.