Given the limited availability of patient-derived cells, our in vitro analyses predominantly focused on healthy human PASMCs [7,159], while also incorporating cells from iPAH patients [7,16] and animal models subjected to disease induction [63,105,108] or hypoxic conditions [63,107,108,109,157,158,160,161], thus providing a representative framework for studying SIRT1-targeted interventions in PH/PAH. The gene discussed is SIRT1; the disease is pulmonary arterial hypertension.