Recently, it has also been discovered that the pro-angiogenic factor VEGF may contribute to M2-like polarization through receptor-mediated signaling (e.g. via VEGFR1) on macrophages, and that the two isoforms of VEGF-A (165a and 165b) can differentially regulate macrophage phenotypes to influence perfusion recovery in PAD [91, 123]. This evidence concerns the gene FLT1 and peripheral arterial disease.