In both control and PAH, genes regulating angiogenesis, migration, adhesion, platelet activation and inflammation were overexpressed, including (kdr, endoglin (eng), pecam1, matrix metallopeptidase 2 (mmp2), (matrix metallopeptidase 12 (mmp12), cldn5, pgf, cd93 molecule (cd93), protocadherin 9 (pcdh9), clusterin (clu), heparin binding egf like growth factor (hbegf), and glycophorin C (gypc)). This evidence concerns the gene CLDN5 and pulmonary arterial hypertension.