Measuring exhaled nitric oxide at high altitude

Hemmingsson, Tryggve E.; Horn, Astrid; Linnarsson, Dag

doi:10.1016/j.resp.2009.06.002

Cited by 24 publications

(35 citation statements)

References 14 publications

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“…By comparison with the results of Hemmingson et al (18) than that in NH during an acute exposure to very high altitude (10 min at 5000 m), the present data additionally show that the exNO can decrease in HH up to 24 h of exposure at an altitude of 3000 m. As proposed, the increased axial back diffusion of NO in the alveolar compartment when BP is decreased (37) coupled with the strong affinity of NO to hemoglobin (23) or pressure-induced suppression of the NO formation in the airways (20) may explain the lower exNO observed in HH. However, exNO should be interpreted with care because values were corrected for flow deviation and sensor sensitivity with correction factors of Hemmingsson et al (17), which may vary due to different subject and/or sensor. Nevertheless, our results are in accordance with previously published results (18) but suggest other mechanisms for differences in ventilatoiy responses between HH and NH based on the interplay between exaggerated oxidative stress and impaired NO bioavailability in blood and tissue.…”

Section: Discussionmentioning

confidence: 99%

“…Experimental design consisted of two different 24-h periods of exposure to HH and NH, in a random order with two groups of three subjects and one group of four subjects. For each subject, experiments were separated by 23 d in average (range, [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32], allowing sufficient elimination of any acclimatization effect.…”

Section: Subjectsmentioning

confidence: 99%

“…For comparison across conditions, the fraction of exNO displayed by the device (ppb) was expressed as the partial pressure of exNO (nm Hg) (8). According to recent recommendations for measurements at altitude (17,20), data obtained in HH at 3000 m were additionally corrected by applying a correction factor to adjust for the mass flow deviation and the higher sensitivity of the sensor at high altitude (see Table 2 in Donnelly et al (8) and Table 1 in Hemmingsson etal. [17]).…”

Section: Biochemical Analysesmentioning

confidence: 99%

“…According to recent recommendations for measurements at altitude (17,20), data obtained in HH at 3000 m were additionally corrected by applying a correction factor to adjust for the mass flow deviation and the higher sensitivity of the sensor at high altitude (see Table 2 in Donnelly et al (8) and Table 1 in Hemmingsson etal. [17]). Plasma nitric oxide, pH level, oxidative stress, and enzymatic antioxidants.…”

Section: Biochemical Analysesmentioning

confidence: 99%

See 3 more Smart Citations

Ventilation, Oxidative Stress, and Nitric Oxide in Hypobaric versus Normobaric Hypoxia

Faiss¹,

Pialoux²,

Sartori³

et al. 2013

Medicine &Amp; Science in Sports &Amp; Exercise

115

139

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show abstract

Section: Discussionmentioning

confidence: 99%

Section: Subjectsmentioning

confidence: 99%

Section: Biochemical Analysesmentioning

confidence: 99%

Section: Biochemical Analysesmentioning

confidence: 99%

See 2 more Smart Citations

Ventilation, Oxidative Stress, and Nitric Oxide in Hypobaric versus Normobaric Hypoxia

Faiss¹,

Pialoux²,

Sartori³

et al. 2013

Medicine &Amp; Science in Sports &Amp; Exercise

115

139

View full text Add to dashboard Cite

show abstract

“…The technical specifications of the instrument list an operating range of barometric pressures from 700 to 1060 hPa or from about 3100m to below sea level. Yet a 2009 paper identified factors that cause the readings to be inaccurate at high altitudes and warned against using the device above 1000m [29]. That paper suggested using two correction factors based on measurement of nine people in a temperature-controlled hypobaric chamber.…”

Section: Methodsmentioning

confidence: 99%

Nitric oxide in adaptation to altitude

Beall

Laskowski

Erzurum

2012

Free Radical Biology and Medicine

122

100

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This review summarizes published information on levels of nitric oxide gas (NO) in the lungs and NO-derived liquid phase molecules in the acclimatization of visitors newly arrived at altitudes of 2500m or more and adaptation of populations whose ancestors arrived thousands of years ago. Studies of acutely exposed visitors to high altitude focus on the first 24–48 hours with just a few extending to days or weeks. Among healthy visitors, NO levels in the lung, plasma and/or red blood cells fell within three hours, but then returned toward baseline or slightly higher by 48 hours, and increased above baseline by 5 days. Among visitors ill with high-altitude pulmonary edema at the time of the study or in the past, NO levels were lower than their healthy counterparts. As for highland populations, Tibetans had NO levels in the lung, plasma and red blood cells that were at least double and in some cases orders of magnitude greater than other populations regardless of altitude. Red blood cell associated nitrogen oxides were more than two hundred times higher. Other highland populations had generally higher levels although not to the degree showed by Tibetans. Overall, responses of those acclimatized and those presumed to be adapted are in the same direction although the Tibetans have much larger responses. Missing are long-term data on lowlanders at altitude showing how similar they become to the Tibetan phenotype. Also missing are data on Tibetans at low altitude to see the extent to which their phenotype is a response to the immediate environment or expressed constitutively. The mechanisms causing the visitors’ and the Tibetans’ high levels of NO and NO-derived molecules at altitude remain unknown. Limited data suggest processes including hypoxic upregulation of NO synthase gene expression, hemoglobin-NO reactions and genetic variation. Gains in understanding will require integrating appropriate methods and measurement techniques with indicators of adaptive function under hypoxic stress.

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Exhaled nitric oxide in ethnically diverse high‐altitude native populations: A comparative study

Ghosh

Kiyamu

Contreras

et al. 2019

American J Phys Anthropol

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Objectives: Andean and Tibetan high-altitude natives exhibit a high concentration of nitric oxide (NO) in the lungs, suggesting that NO plays an adaptive role in offsetting hypobaric hypoxia. We examined the exhaled NO concentration as well as partial pressure of several additional high-altitude native populations in order to examine the possibility that this putative adaptive trait, that is, high exhaled NO, is universal. Methods: We recruited two geographically diverse highland native populations, Tawang Monpa (TM), a Tibetan derived population in North-Eastern India (n = 95, sampled at an altitude of~3,200 m), and Peruvian Quechua from the highland Andes (n = 412). The latter included three distinct subgroups defined as those residing at altitude (Q-HAR, n = 110, sampled at 4,338 m), those born and residing at sea-level (Q-BSL, n = 152), and those born at altitude but migrant to sea-level (Q-M, n = 150).In addition, we recruited a referent sample of lowland natives of European ancestry from Syracuse, New York. Fraction of exhaled NO concentrations were measured using a NIOX NIMO following the protocol of the manufacturer.Results: Partial pressure of exhaled nitric oxide (PENO) was significantly lower (p < .05) in both high-altitude resident groups (TM = 6.2 ± 0.5 nmHg and Q-HAR = 5.8 ± 0.5 nmHg), as compared to the groups measured at sea level (USA = 14.6 ± 0.7 nmHg, Q-BSL = 18.9 ± 1.6 nmHg, and Q-M = 19.2 ± 1.7 nmHg).PENO was not significantly different between TM and Q-HAR (p < .05).Conclusion: In contrast to previous work, we found lower PENO in populations at altitude (compared to sea-level) and no difference in PENO between Tibetan and Andean highland native populations. These results do not support the hypothesis that high nitric oxide in human lungs is a universal adaptive mechanism of highland native populations to offset hypobaric hypoxia. K E Y W O R D SAndean Quechua, exhaled nitric oxide, hypobaric hypoxia, Tawang Monpa

show abstract

Measuring exhaled nitric oxide at high altitude

Cited by 24 publications

References 14 publications

Ventilation, Oxidative Stress, and Nitric Oxide in Hypobaric versus Normobaric Hypoxia

Ventilation, Oxidative Stress, and Nitric Oxide in Hypobaric versus Normobaric Hypoxia

Nitric oxide in adaptation to altitude

Exhaled nitric oxide in ethnically diverse high‐altitude native populations: A comparative study

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