Earlier studies showed that CXCL12 was elevated in plasma and CXCR4 was significantly upregulated in hypoxia-induced PAH rats, and the same trend was observed in clinical samples; pharmacological inhibition of CXCR4 reversed RV hypertrophy, pulmonary artery middle layer hypertrophy and pulmonary vascular remodeling in PAH rats (Xu et al., 2021). This evidence concerns the gene CXCL12 and pulmonary arterial hypertension.