SIRT1 and pulmonary arterial hypertension: Therefore, targeting SIRT1 activity—through its anti-inflammatory, antioxidant, antiproliferative, and pro-apoptotic effects, as well as by restoring mitochondrial biogenesis, may lead to improvement of the PASMC phenotype and may represent a novel therapeutic approach to inhibit vascular remodeling and delay the progression of PAH (summarized in Figure 4).