title: Respiratory nitric oxide and pulmonary artery pressure in children of aymara and European ancestry at high altitude.
abstract: 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.
authors.affiliation: Swiss Cardiovascular Center Bern, University Hospital, Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Stuber
authors.affiliation: Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
authors.forename: Claudio
authors.initials: C
authors.lastname: Sartori
authors.affiliation: Instituto Boliviano de Biologia de Altura, La Paz, Bolivia.
authors.forename: Carlos Salinas
authors.initials: CS
authors.lastname: Salmòn
authors.affiliation: Swiss Cardiovascular Center Bern, University Hospital, Bern, Switzerland.
authors.forename: Damian
authors.initials: D
authors.lastname: Hutter
authors.affiliation: Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Thalmann
authors.affiliation: Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
authors.forename: Pierre
authors.initials: P
authors.lastname: Turini
authors.affiliation: Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Jayet
authors.affiliation: Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
authors.forename: Marcos
authors.initials: M
authors.lastname: Schwab
authors.affiliation: Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
authors.forename: Céline
authors.initials: C
authors.lastname: Sartori-Cucchia
authors.affiliation: Instituto Boliviano de Biologia de Altura, La Paz, Bolivia.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Villena
authors.affiliation: Department of Internal Medicine and Botnar Center for Extreme Medicine, University Hospital, Lausanne, Switzerland.
authors.forename: Urs
authors.initials: U
authors.lastname: Scherrer
authors.affiliation: Swiss Cardiovascular Center Bern, University Hospital, Bern, Switzerland. Electronic address: yves.allemann@insel.ch.
authors.forename: Yves
authors.initials: Y
authors.lastname: Allemann
mesh_terms: 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
chemical_list: D009569:Nitric Oxide