TY - JOUR
T1 - The role of angiotensin II receptor-1 blockade in the hypoxic pulmonary vasoconstriction response in newborn piglets
AU - Camelo, José Simon
AU - Hehre, Dorothy
AU - Devia, Carlos
AU - Camelo, Sílvia Helena Henriques
AU - Bancalari, Eduardo
AU - Suguihara, Cleide
PY - 2008/6/1
Y1 - 2008/6/1
N2 - Background: Angiotensin-converting enzyme activity is increased in newborn infants with respiratory distress syndrome and in animals with alveolar hypoxia. Objective: To test whether angiotensin II (Ang II) mediates the pulmonary vasoconstriction induced by acute hypoxia in newborn piglets. Methods: Eight unanesthetized chronically instrumented newborn piglets (mean ± SEM; age 6.6 ± 0.6 days; weight 2,181 ± 174 g) were randomly assigned to receive a saline solution or the Ang II type 1 receptor (AT1) antagonist, losartan, in a crossover study design, with an interval of at least 48 h between the first and second study. Pulmonary artery (Ppa), wedge, systemic arterial (Psa) and right atrial pressures, cardiac output (CO), pulmonary (PVR) and systemic (SVR) vascular resistances, and arterial blood gases were obtained in room air, before and during the saline or losartan infusion (6 mg/kg followed by 3 mg/kg/h), and during 6 h of hypoxia (FiO2 = 0.11) and saline or losartan infusion. Data were analyzed by repeated measures analysis of variance. Results: The pulmonary vasoconstriction induced by acute hypoxia was significantly attenuated during losartan infusion, while Psa, SVR, CO, pH, PaCO2, PaO2 and base excess did not differ between groups. During room air, Ppa, PVR, Psa, SVR and CO values were not modified by saline or losartan infusion. Conclusion: These data suggest that the pulmonary vasoconstriction induced by acute hypoxia in newborn piglets is partially mediated by Ang II, acting via AT1.
AB - Background: Angiotensin-converting enzyme activity is increased in newborn infants with respiratory distress syndrome and in animals with alveolar hypoxia. Objective: To test whether angiotensin II (Ang II) mediates the pulmonary vasoconstriction induced by acute hypoxia in newborn piglets. Methods: Eight unanesthetized chronically instrumented newborn piglets (mean ± SEM; age 6.6 ± 0.6 days; weight 2,181 ± 174 g) were randomly assigned to receive a saline solution or the Ang II type 1 receptor (AT1) antagonist, losartan, in a crossover study design, with an interval of at least 48 h between the first and second study. Pulmonary artery (Ppa), wedge, systemic arterial (Psa) and right atrial pressures, cardiac output (CO), pulmonary (PVR) and systemic (SVR) vascular resistances, and arterial blood gases were obtained in room air, before and during the saline or losartan infusion (6 mg/kg followed by 3 mg/kg/h), and during 6 h of hypoxia (FiO2 = 0.11) and saline or losartan infusion. Data were analyzed by repeated measures analysis of variance. Results: The pulmonary vasoconstriction induced by acute hypoxia was significantly attenuated during losartan infusion, while Psa, SVR, CO, pH, PaCO2, PaO2 and base excess did not differ between groups. During room air, Ppa, PVR, Psa, SVR and CO values were not modified by saline or losartan infusion. Conclusion: These data suggest that the pulmonary vasoconstriction induced by acute hypoxia in newborn piglets is partially mediated by Ang II, acting via AT1.
KW - Angiotensin II
KW - Hypoxemia
KW - Newborn piglets
KW - Pulmonary arterial hypertension
KW - Receptor antagonist, angiotensin II
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U2 - 10.1159/000111879
DO - 10.1159/000111879
M3 - Article
C2 - 18043007
AN - SCOPUS:44849115735
VL - 93
SP - 263
EP - 268
JO - Neonatology
JF - Neonatology
SN - 1661-7800
IS - 4
ER -