Increased PWV resulting from large arterial stiffening has been associated with proinflammatory responses (increased TLR2, NF-kB activation) in pulmonary arterial ECs in vitro and in intralobar pulmonary arterial ECs from humans with idiopathic pulmonary arterial hypertension (Tan et al., 2014). Here, TLR2 is linked to idiopathic pulmonary arterial hypertension.