PTGDR and pulmonary arterial hypertension: We examined 1) whether expression levels of RAGE and S100A8/A9, ligands of RAGE, were elevated in PAH-PASMCs, 2) whether platelet-derived growth factor (PDGF)-BB, an intense growth factor of PASMCs, up-regulated the expression of RAGE and 3) whether AS-1, an inhibitor of RAGE signaling, has anti-proliferative effects on PAH-PASMCs.