FLT1 and peripheral arterial disease: During reductions in physiological oxygen levels, the master transcriptional activator, hypoxia inducible factor1-α (HIF-1α), induces expression of a number of angiogenic mediators including vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), granulocyte- and granulocyte macrophage colony stimulating factors (G- and GM-CSF), and the VEGF receptors, Flt-1 (VEGFR-1) and Flk-1 (VEGFR-2) 8-11, each of which has been considered as a therapeutic target for the management of PAD 12.