2. Academic Validation
  3. Riociguat versus sildenafil on hypoxic pulmonary vasoconstriction and ventilation/perfusion matching

Riociguat versus sildenafil on hypoxic pulmonary vasoconstriction and ventilation/perfusion matching

  • PLoS One. 2018 Jan 24;13(1):e0191239. doi: 10.1371/journal.pone.0191239.
Virginia Chamorro 1 2 3,  Daniel Morales-Cano 1 2 3,  Javier Milara 4 5,  Bianca Barreira 1 2 3,  Laura Moreno 1 2 3,  María Callejo 1 2 3,  Gema Mondejar-Parreño 1 2 3,  Sergio Esquivel-Ruiz 1 2 3,  Julio Cortijo 2 4 5,  Ángel Cogolludo 1 2 3,  Joan A Barberá 2 6,  Francisco Perez-Vizcaino 1 2 3
Affiliations

Affiliations

  • 1 Departamento de Farmacología. Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.
  • 2 Ciber Enfermedades Respiratorias (Ciberes), Madrid, Spain.
  • 3 Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.
  • 4 Dept of Pharmacology, Faculty of Medicine, University of Valencia, Valencia, Spain.
  • 5 Clinical Research Unit (UIC), University General Hospital Consortium, Valencia, Spain.
  • 6 Department of Pulmonary Medicine, Hospital Clínic-Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain.
PMID: 29364918 DOI: 10.1371/journal.pone.0191239
Abstract

Introduction: Current treatment with vasodilators for pulmonary hypertension associated with respiratory diseases is limited by their inhibitory effect on hypoxic pulmonary vasoconstriction (HPV) and uncoupling effects on ventilation-perfusion (V'/Q'). Hypoxia is also a well-known modulator of the nitric oxide (NO) pathway, and may therefore differentially affect the responses to phosphodiesterase 5 (PDE5) inhibitors and soluble guanylyl cyclase (sGC) stimulators. So far, the effects of the sGC stimulator riociguat on HPV have been poorly characterized.

Materials and methods: Contraction was recorded in pulmonary arteries (PA) in a wire myograph. Anesthetized rats were catheterized to record PA pressure. Ventilation and perfusion were analyzed by micro-CT-SPECT images in rats with pulmonary fibrosis induced by bleomycin.

Results: The PDE5 Inhibitor sildenafil and the sGC stimulator riociguat similarly inhibited HPV in vitro and in vivo. Riociguat was more effective as vasodilator in isolated rat and human PA than sildenafil. Riociguat was ≈3-fold more potent under hypoxic conditions and it markedly inhibited HPV in vivo at a dose that barely affected the thromboxane A2 (TXA2) mimetic U46619-induced pressor responses. Pulmonary fibrosis was associated with V'/Q' uncoupling and riociguat did not affect the V'/Q' ratio.

Conclusion: PDE5 inhibitors and sGC stimulators show a different vasodilator profile. Riociguat was highly effective and potentiated by hypoxia in rat and human PA. In vivo, riociguat preferentially inhibited hypoxic than non-hypoxic vasoconstriction. However, it did not worsen V'/Q' coupling in a rat model of pulmonary fibrosis.

Figures
Products