Growth factors involved in vascular remodeling in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare and fatal cardiovascular disease characterized by pulmonary vascular remodeling, leading to a progressive increase in pulmonary vascular resistance and pulmonary arterial pressure (PAP). Elevated PAP induces right ventricular hypertrophy and eventually progresses to right heart failure. Pulmonary vascular remodeling is primarily caused by the excessive proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) in the medial layer. This is mediated by the binding of growth factors to their specific receptor tyrosine kinases. To date, several growth factors, including epidermal growth factor, fibroblast growth factor, insulin-like growth factor, platelet-derived growth factor (PDGF), transforming growth factor-β, and vascular endothelial growth factor, have been implicated in the development of PAH. Our previous studies have demonstrated that the upregulated expression of Ca²⁺-sensing receptors in PASMCs contributes to the development of PAH. This upregulation was induced by increased PDGF levels in PASMCs from PAH patients. Therefore, imatinib (a tyrosine kinase inhibitor including PDGF receptors) and corosolic acid (with inhibitory effects of PDGF signaling) suppressed the excessive proliferation and migration of PASMCs from PAH patients. These treatments also ameliorated pulmonary vascular remodeling in pulmonary hypertensive rats. This review focuses on the pathological roles of growth factors, especially PDGF, in the pathogenesis and progression of PAH.