CYP19A1 and pulmonary arterial hypertension: There are several studies demonstrating that systemic levels of E2 are higher in patients with PAH as compared to age and body mass-matched controls (Ventetuolo et al., 2016); local estrogen concentration and aromatase enzyme levels in PASMCs from women are higher compared to men (Wright et al., 2015); and absence of hemodynamic differences and RV indices between male and female PAH patients who are older than 45 years-old (Ventetuolo et al., 2011).