At birth, pulmonary vasodilation occurs in association with an increase in oxygen tension. When pulmonary artery (PA) pressure does not decrease, persistent pulmonary hypertension of the newborn (PPHN) results. PPHN is characterized by increased pulmonary vascular tone and reactivity, and an incomplete response to perinatal vasodilator stimuli, including oxygen. Data from our laboratory have demonstrated that the pulmonary circulation responds to an acute increase in oxygen tension via calcium-sensitive K+ channel (BKCa) activation mediated by Ca2+ release from a developmentally regulated ryanodine-sensitive store. Despite the critical importance of oxygen in mediating perinatal pulmonary vasodilation, how oxygen sensing is compromised in PPHN remains unknown. Preliminary data indicate that in an ovine model of PPHN, pulmonary artery smooth muscle cell (PA SMC) BKCa channel expression, oxygen sensing and intracellular cellular Ca2+ homeostasis are compromised. The present proposal tests the working hypothesis that in an animal model of PPHN, pulmonary artery smooth muscle cell oxygen sensing is compromised, thereby attenuating perinatal pulmonary vasodilation.
The specific aims are to test the hypotheses that in an ovine model of perinatal pulmonary hypertension:
Aim 1. O2 sensing is compromised through both direct and indirect effects on BKCa channel activation;
and Aim 2. BKCa channel subunit expression modulates PA SMC O2 sensing. The studies proposed in the present application will determine whether the attenuated response of the pulmonary circulation to vasodilator stimuli, the hallmark of PPHN, results from compromised PA SMC BKCa expression and/or function. Completion of the proposed studies may identify specific molecular target for the development of novel K+ channel based strategies to address a profoundly difficult clinical problem. The strategy of modulating BKCa channel subunit expression to enhance pulmonary vasodilation may be more broadly applicable to other vascular diseases. ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL060784-05A3
Application #
7038825
Study Section
Respiratory Integrative Biology and Translational Research Study Section (RIBT)
Program Officer
Berberich, Mary Anne
Project Start
1999-09-30
Project End
2010-08-31
Budget Start
2006-09-01
Budget End
2007-08-31
Support Year
5
Fiscal Year
2006
Total Cost
$359,125
Indirect Cost
Name
Stanford University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
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Cornfield, David N (2016) Shifting the Paradigm in Hemolytic Uremic Syndrome. Pediatrics 137:
Cornfield, David N; Bhargava, Sumit (2015) Sleep medicine: pediatric polysomnography revisited. Curr Opin Pediatr 27:325-8
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Alvira, Cristina M; Umesh, Anita; Husted, Cristiana et al. (2012) Voltage-dependent anion channel-2 interaction with nitric oxide synthase enhances pulmonary artery endothelial cell nitric oxide production. Am J Respir Cell Mol Biol 47:669-78

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