Respiratory nitric oxide and pulmonary artery pressure in children of aymara and European ancestry at high altitude.
Invasive studies suggest that healthy children living at high altitude display pulmonary hypertension, but the data to support this assumption are sparse. Nitric oxide (NO) synthesized by the respiratory epithelium regulates pulmonary artery pressure, and its synthesis was reported to be increased in Aymara high-altitude dwellers. We hypothesized that pulmonary artery pressure will be lower in Aymara children than in children of European ancestry at high altitude, and that this will be related to increased respiratory NO. We therefore compared pulmonary artery pressure and exhaled NO (a marker of respiratory epithelial NO synthesis) between large groups of healthy children of Aymara (n = 200; mean +/- SD age, 9.5 +/- 3.6 years) and European ancestry (n = 77) living at high altitude (3,600 to 4,000 m). We also studied a group of European children (n = 29) living at low altitude. The systolic right ventricular to right atrial pressure gradient in the Aymara children was normal, even though significantly higher than the gradient measured in European children at low altitude (22.5 +/- 6.1 mm Hg vs 17.7 +/- 3.1 mm Hg, p < 0.001). In children of European ancestry studied at high altitude, the pressure gradient was 33% higher than in the Aymara children (30.0 +/- 5.3 mm Hg vs 22.5 +/- 6.1 mm Hg, p < 0.0001). In contrast to what was expected, exhaled NO tended to be lower in Aymara children than in European children living at the same altitude (12.4 +/- 8.8 parts per billion [ppb] vs 16.1 +/- 11.1 ppb, p = 0.06) and was not related to pulmonary artery pressure in either group. Aymara children are protected from hypoxic pulmonary hypertension at high altitude. This protection does not appear to be related to increased respiratory NO synthesis.
Stuber
Thomas
T
Swiss Cardiovascular Center Bern, University Hospital, Bern, Switzerland.
Sartori
Claudio
C
Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Salmòn
Carlos Salinas
CS
Instituto Boliviano de Biologia de Altura, La Paz, Bolivia.
Hutter
Damian
D
Swiss Cardiovascular Center Bern, University Hospital, Bern, Switzerland.
Thalmann
Sébastien
S
Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Turini
Pierre
P
Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Jayet
Pierre-Yves
PY
Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Schwab
Marcos
M
Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Sartori-Cucchia
Céline
C
Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Villena
Mercedes
M
Instituto Boliviano de Biologia de Altura, La Paz, Bolivia.
Scherrer
Urs
U
Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Allemann
Yves
Y
Swiss Cardiovascular Center Bern, University Hospital, Bern, Switzerland. Electronic address: yves.allemann@insel.ch.
D000222:Adaptation, Physiological; D000293:Adolescent; D000388:Air / Q000032:analysis; D000531:Altitude; D001838:Bolivia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005060:Europe / Q000208:ethnology; D045853:Exhalation / Q000502:physiology*; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000208:ethnology* / Q000209:etiology / Q000503:physiopathology; D000860:Hypoxia / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D015994:Incidence; D007223:Infant; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D011669:Pulmonary Wedge Pressure / Q000502:physiology*; D012307:Risk Factors
D009569:Nitric Oxide