Chronic hypoxia-induced pulmonary hypertension was significantly attenuated or delayed in mice hemizygous for either HIF1α [245] or HIF2α [246,247] and in mice with vascular smooth muscle HIF1α [248], endothelial, or global partial HIF2α deletion [249,250,251]. Here, EPAS1 is linked to pulmonary arterial hypertension.