CXCR4 and pulmonary hypertension: Selective CXCR4 antagonist, promoting inhibition of the SDF-1/CXCR4 axis, which significantly improved lung alveolarization and decreased pulmonary hypertension, right ventricular hypertrophy, vascular remodeling, vascular cell proliferation, and lung or right ventricular stem cell expressions in murine model.