NTRK1 and pulmonary arterial hypertension: BIBF1000, an orally active potent inhibitor of the receptor tyrosine kinases for VEGF, FGF, and PDGF, prevents and reverses the progression of severe pulmonary arterial hypertension, inhibits pulmonary arterial neointimal formation, attenuates right heart hypertrophy, and improves survival in an experimental model of PAH [20].