Pulmonary-artery pressure and exhaled nitric oxide in Bolivian and Caucasian high altitude dwellers.
There is evidence that high altitude populations may be better protected from hypoxic pulmonary hypertension than low altitude natives, but the underlying mechanism is incompletely understood. In Tibetans, increased pulmonary respiratory NO synthesis attenuates hypoxic pulmonary hypertension. It has been speculated that this mechanism may represent a generalized high altitude adaptation pattern, but direct evidence for this speculation is lacking. We therefore measured systolic pulmonary-artery pressure (Doppler chocardiography) and exhaled nitric oxide (NO) in 34 healthy, middle-aged Bolivian high altitude natives and in 34 age- and sex-matched, well-acclimatized Caucasian low altitude natives living at high altitude (3600 m). The mean+/-SD systolic right ventricular to right atrial pressure gradient (24.3+/-5.9 vs. 24.7+/-4.9 mmHg) and exhaled NO (19.2+/-7.2 vs. 22.5+/-9.5 ppb) were similar in Bolivians and Caucasians. There was no relationship between pulmonary-artery pressure and respiratory NO in the two groups. These findings provide no evidence that Bolivian high altitude natives are better protected from hypoxic pulmonary hypertension than Caucasian low altitude natives and suggest that attenuation of pulmonary hypertension by increased respiratory NO synthesis may not represent a universal adaptation pattern in highaltitude populations.
Schwab
Marcos
M
Department of Internal Medicine and Botnar Centre for Extreme Medicine, University Hospital, Lausanne, Switzerland.
Jayet
Pierre-Yves
PY
Stuber
Thomas
T
Salinas
Carlos E
CE
Bloch
Jonathan
J
Spielvogel
Hilde
H
Villena
Mercedes
M
Allemann
Yves
Y
Sartori
Claudio
C
Scherrer
Urs
U
D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D000531:Altitude; D001794:Blood Pressure / Q000502:physiology*; D001838:Bolivia; D004784:Environmental Monitoring; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D007199:Indians, South American; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D010092:Oximetry; D011651:Pulmonary Artery / Q000502:physiology; D012307:Risk Factors; D044465:White People
D009569:Nitric Oxide