By similarly using the in vivo intratracheal delivery of an Ad vector containing the BMPR2 gene, other studies successfully up-regulated the expression of BMPR2 and restored SMAD-1/5/8 signaling in the pulmonary vasculature and reduced the proliferation of vascular cells in experimental PAH models [94,95]. Here, BMPR2 is linked to pulmonary arterial hypertension.