In addition to three categories of FDA-approved treatments including prostanoids, ET-1 receptor antagonists, and phosphodiesterase 5 (PDE5) inhibitors, PPARγ agonists thiazolidinediones (TZDs) including rosiglitazone and pioglitazone have shown beneficial effects in animal models of PAH. This evidence concerns the gene PDE5A and pulmonary arterial hypertension.