SIRT3 and idiopathic pulmonary arterial hypertension: In a previous study, we demonstrated that treatment of pulmonary artery adventitial fibroblasts isolated from IPAH patients and hypoxia-induced PH bovines (PH-Fibs) with a combination of the SIRT3 activator Honokiol and the SIRT3 co-factor nicotinamide adenine dinucleotide (NAD+) improved mitochondrial function and inhibited the proliferation of PH-Fibs [32].