Persistent pulmonary hypertension of the newborn (PPHN) is a serious clinical problem that affects up to 10% of infants admitted to the Neonatal Intensive Care Unit, and occurs when pulmonary vascular resistance does not decrease normally during the transition to air breathing at birth. We have utilized a fetal lamb model of PPHN to study the vascular changes associated with PPHN, and to determine how these changes might interfere with the normal pulmonary vascular transition. Our preliminary data in PPHN lambs strongly suggest: 1) a central role for reactive oxygen species (ROS) in the pathogenesis of PPHN;2) that hyperoxia enhances production of ROS by mitochondrial and cytosolic sources, which increase vascular reactivity, and 3) that the PPHN lamb is particularly vulnerable to the effects of hyperoxia, responding with exaggerated increases in ROS and vascular dysfunction. We hypothesize We propose three specific aims to further our knowledge of the pathogenesis and therapeutic opportunities for PPHN: 1. Determine abnormalities of vascular mitochondrial and cytosolic ROS production specific to PPHN. 2. Determine the effect of hyperoxia on ROS production in the PPHN vasculature. 3. Determine the effects of therapeutic strategies targeted at reducing ROS production in specific cellular compartments. An improved understanding of the mechanistic basis for this syndrome will potentially identify novel clinical approaches to managing the vascular dysfunction that characterizes PPHN. Such therapies could dramatically improve immediate and long-term clinical outcomes, while substantially reducing the health care costs associated with this syndrome.

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We expect our studies to improve our understanding of the causes of persistent pulmonary hypertension, a serious medical condition that affects 10% of infants admitted for neonatal intensive care. Our research should lead to therapies that reduce oxygen toxicity, improve immediate and long- term clinical outcomes, and substantially reduce the health care costs associated with this syndrome.

National Institute of Health (NIH)
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Respiratory Integrative Biology and Translational Research Study Section (RIBT)
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Lin, Sara
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Northwestern University at Chicago
Schools of Medicine
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Lee, Keng Jin; Berkelhamer, Sara K; Kim, Gina A et al. (2014) Disrupted pulmonary artery cyclic guanosine monophosphate signaling in mice with hyperoxia-induced pulmonary hypertension. Am J Respir Cell Mol Biol 50:369-78
Berkelhamer, Sara K; Mestan, Karen K; Steinhorn, Robin H (2013) Pulmonary hypertension in bronchopulmonary dysplasia. Semin Perinatol 37:124-31
Shah, Monica R; Wedgwood, Stephen; Czech, Lyubov et al. (2013) Cyclic stretch induces inducible nitric oxide synthase and soluble guanylate cyclase in pulmonary artery smooth muscle cells. Int J Mol Sci 14:4334-48
Steinhorn, Robin H (2013) Diagnosis and treatment of pulmonary hypertension in infancy. Early Hum Dev 89:865-74
Porta, Nicolas F M; Steinhorn, Robin H (2012) Pulmonary vasodilator therapy in the NICU: inhaled nitric oxide, sildenafil, and other pulmonary vasodilating agents. Clin Perinatol 39:149-64
Bishop, Naomi B; Stankiewicz, Pawel; Steinhorn, Robin H (2011) Alveolar capillary dysplasia. Am J Respir Crit Care Med 184:172-9
Wedgwood, Stephen; Lakshminrusimha, Satyan; Fukai, Tohru et al. (2011) Hydrogen peroxide regulates extracellular superoxide dismutase activity and expression in neonatal pulmonary hypertension. Antioxid Redox Signal 15:1497-506
Steinhorn, Robin H (2011) Therapeutic approaches using nitric oxide in infants and children. Free Radic Biol Med 51:1027-34
Mestan, Karen K; Steinhorn, Robin H (2011) Fetal origins of neonatal lung disease: understanding the pathogenesis of bronchopulmonary dysplasia. Am J Physiol Lung Cell Mol Physiol 301:L858-9
Farrow, Kathryn N; Steinhorn, Robin H (2011) Phosphodiesterases: emerging therapeutic targets for neonatal pulmonary hypertension. Handb Exp Pharmacol :251-77

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