Figure 3.

Erythropoietin (EPO) from pulmonary arterial hypertension (PAH) serum promotes pulmonary artery smooth muscle cell (SMC) proliferation in vitro. A, Increased concentrations of recombitant human EPO (10, 50, or 100 IU/mL) promote SMC proliferation in a dose-dependent manner. B, C, Treatment of SMCs with 10% idiopathic PAH (IPAH) serum increases their proliferation, which was inhibited by EPO-neutralizing antibody in a dose-dependent manner. Immunoglobulin G (IgG) control antibody did not affect SMC proliferation (B). Asterisk indicates P < 0.05.