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High-altitude chronic hypoxia during gestation and after birth modifies cardiovascular responses in newborn sheep

High-altitude chronic hypoxia during gestation and after birth modifies cardiovascular responses in newborn sheep
High-altitude chronic hypoxia during gestation and after birth modifies cardiovascular responses in newborn sheep
Perinatal exposure to chronic hypoxia induces sustained pulmonary hypertension and structural and functional changes in both pulmonary and systemic vascular beds. The aim of this study was to analyze consequences of high-altitude chronic hypoxia during gestation and early after birth in pulmonary and femoral vascular responses in newborn sheep. Lowland (LLNB; 580 m) and highland (HLNB; 3,600 m) newborn lambs were cathetherized under general anesthesia and submitted to acute sustained or stepwise hypoxic episodes. Contractile and dilator responses of isolated pulmonary and femoral small arteries were analyzed in a wire myograph. Under basal conditions, HLNB had a higher pulmonary arterial pressure (PAP; 20.2 +/- 2.4 vs. 13.6 +/- 0.5 mmHg, P < 0.05) and cardiac output (342 +/- 23 vs. 279 +/- 13 ml x min(-1) x kg(-1), P < 0.05) compared with LLNB. In small pulmonary arteries, HLNB showed greater contractile capacity and higher sensitivity to nitric oxide. In small femoral arteries, HLNB had lower maximal contraction than LLNB with higher maximal response and sensitivity to noradrenaline and phenylephrine. In acute superimposed hypoxia, HLNB reached higher PAP and femoral vascular resistance than LLNB. Graded hypoxia showed that average PAP was always higher in HLNB compared with LLNB at any Po2. Newborn lambs from pregnancies at high altitude have stronger pulmonary vascular responses to acute hypoxia associated with higher arterial contractile status. In addition, systemic vascular response to acute hypoxia is increased in high-altitude newborns, associated with higher arterial adrenergic responses. These responses determined in intrauterine life and early after birth could be adaptive to chronic hypoxia in the Andean altiplano
hypoxemia, pulmonary hypertension, vascular reactivity, neonatal lamb, highlands
0363-6119
R2234-R2240
Herrera, Emilio A.
a77afc79-2a4d-41d7-a777-9fff78bc6248
Pulgar, Victor M.
dbb82a85-9a03-413b-918f-e25df0da8e36
Riquelme, Raquel A.
fede260a-6eee-484b-b080-f1382d024d87
Sanhueza, Emilia M.
a7e07d46-486b-4934-ad1e-d7ec387658be
Reyes, Roberto V.
5cfda85b-48b9-43d7-a878-0c6630f70a00
Ebensperger, German
fe05101a-f792-49d0-b20e-6d4594185828
Parer, Julian T.
1ecf6b51-870e-41e4-b15f-b009c81a15cc
Valdez, Enrique A.
3402dd0a-6096-4007-87b1-8075ba4a223b
Giussani, Dino A.
d217c140-284c-4371-a9a6-49638fd11263
Blanco, Carlos E.
6f5ad3bc-01cd-4d12-93c7-459156784f8a
Hanson, Mark A.
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Llanos, Anibal J.
312713ac-6a6e-4c4c-b0ae-541c36ce4e9a
Herrera, Emilio A.
a77afc79-2a4d-41d7-a777-9fff78bc6248
Pulgar, Victor M.
dbb82a85-9a03-413b-918f-e25df0da8e36
Riquelme, Raquel A.
fede260a-6eee-484b-b080-f1382d024d87
Sanhueza, Emilia M.
a7e07d46-486b-4934-ad1e-d7ec387658be
Reyes, Roberto V.
5cfda85b-48b9-43d7-a878-0c6630f70a00
Ebensperger, German
fe05101a-f792-49d0-b20e-6d4594185828
Parer, Julian T.
1ecf6b51-870e-41e4-b15f-b009c81a15cc
Valdez, Enrique A.
3402dd0a-6096-4007-87b1-8075ba4a223b
Giussani, Dino A.
d217c140-284c-4371-a9a6-49638fd11263
Blanco, Carlos E.
6f5ad3bc-01cd-4d12-93c7-459156784f8a
Hanson, Mark A.
1952fad1-abc7-4284-a0bc-a7eb31f70a3f
Llanos, Anibal J.
312713ac-6a6e-4c4c-b0ae-541c36ce4e9a

Herrera, Emilio A., Pulgar, Victor M., Riquelme, Raquel A., Sanhueza, Emilia M., Reyes, Roberto V., Ebensperger, German, Parer, Julian T., Valdez, Enrique A., Giussani, Dino A., Blanco, Carlos E., Hanson, Mark A. and Llanos, Anibal J. (2007) High-altitude chronic hypoxia during gestation and after birth modifies cardiovascular responses in newborn sheep. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 292 (6), R2234-R2240. (doi:10.1152/ajpregu.00909.2006).

Record type: Article

Abstract

Perinatal exposure to chronic hypoxia induces sustained pulmonary hypertension and structural and functional changes in both pulmonary and systemic vascular beds. The aim of this study was to analyze consequences of high-altitude chronic hypoxia during gestation and early after birth in pulmonary and femoral vascular responses in newborn sheep. Lowland (LLNB; 580 m) and highland (HLNB; 3,600 m) newborn lambs were cathetherized under general anesthesia and submitted to acute sustained or stepwise hypoxic episodes. Contractile and dilator responses of isolated pulmonary and femoral small arteries were analyzed in a wire myograph. Under basal conditions, HLNB had a higher pulmonary arterial pressure (PAP; 20.2 +/- 2.4 vs. 13.6 +/- 0.5 mmHg, P < 0.05) and cardiac output (342 +/- 23 vs. 279 +/- 13 ml x min(-1) x kg(-1), P < 0.05) compared with LLNB. In small pulmonary arteries, HLNB showed greater contractile capacity and higher sensitivity to nitric oxide. In small femoral arteries, HLNB had lower maximal contraction than LLNB with higher maximal response and sensitivity to noradrenaline and phenylephrine. In acute superimposed hypoxia, HLNB reached higher PAP and femoral vascular resistance than LLNB. Graded hypoxia showed that average PAP was always higher in HLNB compared with LLNB at any Po2. Newborn lambs from pregnancies at high altitude have stronger pulmonary vascular responses to acute hypoxia associated with higher arterial contractile status. In addition, systemic vascular response to acute hypoxia is increased in high-altitude newborns, associated with higher arterial adrenergic responses. These responses determined in intrauterine life and early after birth could be adaptive to chronic hypoxia in the Andean altiplano

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Published date: June 2007
Keywords: hypoxemia, pulmonary hypertension, vascular reactivity, neonatal lamb, highlands

Identifiers

Local EPrints ID: 61210
URI: http://eprints.soton.ac.uk/id/eprint/61210
ISSN: 0363-6119
PURE UUID: 6d3ebc32-da4d-4a8a-a901-dc1853b4c780
ORCID for Mark A. Hanson: ORCID iD orcid.org/0000-0002-6907-613X

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Date deposited: 20 Mar 2009
Last modified: 16 Mar 2024 03:17

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Contributors

Author: Emilio A. Herrera
Author: Victor M. Pulgar
Author: Raquel A. Riquelme
Author: Emilia M. Sanhueza
Author: Roberto V. Reyes
Author: German Ebensperger
Author: Julian T. Parer
Author: Enrique A. Valdez
Author: Dino A. Giussani
Author: Carlos E. Blanco
Author: Mark A. Hanson ORCID iD
Author: Anibal J. Llanos

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