revealed that FGF21 increased the content of nicotinamide adenine dinucleotide (NAD+) through an AMPK-dependent pathway and improved hyperglycemia-related ischemic angiogenesis and endothelial progenitor cell (EPC) function, which was critical for investigating T2DM complications, especially CAD (25). Here, FGF21 is linked to type 2 diabetes mellitus.