TNF and pulmonary arterial hypertension: This is also in concordance with data that have shown that patients with idiopathic and hereditary PAH have increased local vascular expression of TNF and that TNF/NF-κB signaling selectively reduces BMPR2 mRNA and BMPR2 protein in distal VSMCs and pulmonary arterial endothelial cells, suggesting that TNF may also play a critical role in human disease (18).