NOS2 and pulmonary arterial hypertension: The following example phrases were used during the search: “pulmonary hypertension monocrotaline iNOS (or NOS2)”, “pulmonary hypertension hypoxia iNOS (or NOS2)”, “pulmonary hypertension emphysema iNOS (or NOS2)” etc. Ultimately, 112 publications were selected for this review, as summarized in Section 5.2, Section 6, Section 7 and Section 8, respectively.