Neonatal hyperoxic lung injury favorably alters adult right ventricular remodeling response to chronic hypoxia exposure

Kara N. Goss, Anthony R. Cucci, Amanda J. Fisher, Marjorie Albrecht, Andrea Frump, Roziya Tursunova, Yong Gao, Mary Beth Brown, Irina Petrache, Robert S. Tepper, Shawn K. Ahlfeld, Tim Lahm

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

The development of pulmonary hypertension (PH) requires multiple pulmonary vascular insults, yet the role of early oxygen therapy as an initial pulmonary vascular insult remains poorly defined. Here, we employ a two-hit model of PH, utilizing postnatal hyperoxia followed by adult hypoxia exposure, to evaluate the role of early hyperoxic lung injury in the development of later PH. Sprague-Dawley pups were exposed to 90% oxygen during postnatal days 0–4 or 0–10 or to room air. All pups were then allowed to mature in room air. At 10 wk of age, a subset of rats from each group was exposed to 2 wk of hypoxia (P<inf>atm</inf>=362 mmHg). Physiological, structural, and biochemical endpoints were assessed at 12 wk. Prolonged (10 days) postnatal hyperoxia was independently associated with elevated right ventricular (RV) systolic pressure, which worsened after hypoxia exposure later in life. These findings were only partially explained by decreases in lung microvascular density. Surprisingly, postnatal hyperoxia resulted in robust RV hypertrophy and more preserved RV function and exercise capacity following adult hypoxia compared with nonhyperoxic rats. Biochemically, RVs from animals exposed to postnatal hyperoxia and adult hypoxia demonstrated increased capillarization and a switch to a fetal gene pattern, suggesting an RV more adept to handle adult hypoxia following postnatal hyperoxia exposure. We concluded that, despite negative impacts on pulmonary artery pressures, postnatal hyperoxia exposure may render a more adaptive RV phenotype to tolerate late pulmonary vascular insults.

Original languageEnglish (US)
Pages (from-to)L797-L806
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume308
Issue number8
DOIs
StatePublished - Jan 1 2015

    Fingerprint

Keywords

  • Atrial natriuretic peptide
  • Prematurity
  • Pulmonary hypertension capillarization
  • Right ventricular adaptation

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology
  • Physiology

Cite this