CXCL12 and pulmonary arterial hypertension: In this regard, PAH EC-conditioned growth medium promotes proliferation of PASMCs likely driven by FoxM1 and the production of paracrine factors endothelin-1, C-X-C motif chemokine ligand 12 (CXCL12), fibroblast growth factor-2 (FGF2), platelet derived growth factor B (PDGFB), and macrophage migration inhibitory factor (MIF) (20, 21).