Effects of Acute Exposure to Moderate Altitude on Vascular Function, Metabolism and Systemic Inflammation

Stöwhas, Anne-Christin; Latshang, Tsogyal D.; Cascio, Christian M. Lo; Lautwein, Sina; Stadelmann, Katrin; Tesler, Noemi; Ayers, Lisa; Berneis, Kaspar; Gerber, Philipp A.; Huber, Reto; Achermann, Peter; Bloch, Konrad E.; Kohler, Malcolm

doi:10.1371/journal.pone.0070081

Cited by 24 publications

(20 citation statements)

References 32 publications

(26 reference statements)

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“…In a study of 51 healthy male volunteers, a two-day stay at moderate altitude (2590 m) also led to a significant reduction in MVs derived from platelets and erythrocytes with no change in endothelial or leucocyte-derived MVs [29]. The changes in this study were associated with a reduction in inflammatory markers and an improvement in lipid profiles [31]. Therefore general systemic effects on vascular health may be of relevance to this change in MV levels.…”

Section: Hypoxiasupporting

confidence: 50%

Dynamic microvesicle release and clearance within the cardiovascular system: triggers and mechanisms

et al. 2015

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Interest in cell-derived microvesicles (or microparticles) within cardiovascular diagnostics and therapeutics is rapidly growing. Microvesicles are often measured in the circulation at a single time point. However, it is becoming clear that microvesicle levels both increase and decrease rapidly in response to certain stimuli such as hypoxia, acute cardiac stress, shear stress, hypertriglyceridaemia and inflammation. Consequently, the levels of circulating microvesicles will reflect the balance between dynamic mechanisms for release and clearance. The present review describes the range of triggers currently known to lead to microvesicle release from different cellular origins into the circulation. Specifically, the published data are used to summarize the dynamic impact of these triggers on the degree and rate of microvesicle release. Secondly, a summary of the current understanding of microvesicle clearance via different cellular systems, including the endothelial cell and macrophage, is presented, based on reported studies of clearance in experimental models and clinical scenarios, such as transfusion or cardiac stress. Together, this information can be used to provide insights into potential underlying biological mechanisms that might explain the increases or decreases in circulating microvesicle levels that have been reported and help to design future clinical studies.

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Section: Hypoxiasupporting

confidence: 50%

Dynamic microvesicle release and clearance within the cardiovascular system: triggers and mechanisms

et al. 2015

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“…Data on the effects of altitude on sleep and cardiovascular function are described elsewhere [12–14], including the consort flow chart (Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

Impaired Postural Control in Healthy Men at Moderate Altitude (1630 M and 2590 M): Data from a Randomized Trial

et al. 2015

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ObjectivesIntact postural control is essential for safe performance of mountain sports, operation of machinery at altitude, and for piloting airplanes. We tested whether exposure to hypobaric hypoxia at moderate altitude impairs the static postural control of healthy subjects.MethodsIn 51 healthy men, median age 24 y (quartiles 20;28), static control was evaluated on a balance platform in Zurich, 490 m, and during a 4-day sojourn in Swiss mountain villages at 1630 m and 2590 m, 2 days each. The order of altitude exposure was randomized. Total center of pressure path length (COPL) and sway amplitude measured in two directions by a balance platform, and pulse oximetry were recorded. Data were compared between altitudes.ResultsMedian (quartiles) COPL during standing on both legs with eyes open at 490 m and in the evenings on the first and second days at 1630 and 2590 m, respectively were: 50 (45;57), 55 (48;62), 56 (49;61), 53 (47;59), 54 (48;60) cm, P<0.001 ANOVA. Corresponding arterial oxygen saturation was 97% (96;97), 95% (94;96), 95%(94;96), 92%(90;93), 93%(91;93), P<0.001. Anterior-posterior sway amplitudes were larger at 1630 and 2590 m compared to 490 m, P<0.001. Multiple logistic regression analysis confirmed that higher altitudes (1630 and 2590m) were independently associated with increased COPL when controlled for the order of altitude exposure and age (P=0.001).ConclusionsExposure to 1630 and 2590m was associated with impaired static postural control even when visual references were available.Trial RegistrationClinicalTrials.gov NCT01130948.

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“…Lights were turned off at 11 p.m. and on at 6 a.m.. The reason for limiting sleep to 7 hours was the circumstantial tests and examinations in the morning and afternoon (see [12], [13]). The protocol consisted of 5 study nights: one baseline night (490 m) and four consecutive nights at moderate altitude (two nights at 1630 m [N1, N2] and two nights 2590 m [N1, N2]) completed in a randomized cross-over design (Figure S1).…”

Section: Methodsmentioning

confidence: 99%

“…Participants were divided into four groups based on the order of altitude exposure (group 1 ( n = 11): 490 m - 1630 m - 2590 m, group 2 ( n = 11): 490 m - 2590 m - 1630 m, group 3 ( n = 12): 1630 m - 2590 m - 490 m and group 4 ( n = 10): 2590 m - 1630 m - 490 m; Figure S1). Every evening before and every morning after a recording, participants completed comprehensive test blocks comprised of medical and cognitive examinations [12], [13].…”

Section: Methodsmentioning

confidence: 99%

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Quantitative Changes in the Sleep EEG at Moderate Altitude (1630 m and 2590 m)

et al. 2013

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BackgroundPrevious studies have observed an altitude-dependent increase in central apneas and a shift towards lighter sleep at altitudes >4000 m. Whether altitude-dependent changes in the sleep EEG are also prevalent at moderate altitudes of 1600 m and 2600 m remains largely unknown. Furthermore, the relationship between sleep EEG variables and central apneas and oxygen saturation are of great interest to understand the impact of hypoxia at moderate altitude on sleep.MethodsFourty-four healthy men (mean age 25.0±5.5 years) underwent polysomnographic recordings during a baseline night at 490 m and four consecutive nights at 1630 m and 2590 m (two nights each) in a randomized cross-over design.ResultsComparison of sleep EEG power density spectra of frontal (F3A2) and central (C3A2) derivations at altitudes compared to baseline revealed that slow-wave activity (SWA, 0.8–4.6 Hz) in non-REM sleep was reduced in an altitude-dependent manner (∼4% at 1630 m and 15% at 2590 m), while theta activity (4.6–8 Hz) was reduced only at the highest altitude (10% at 2590 m). In addition, spindle peak height and frequency showed a modest increase in the second night at 2590 m. SWA and theta activity were also reduced in REM sleep. Correlations between spectral power and central apnea/hypopnea index (AHI), oxygen desaturation index (ODI), and oxygen saturation revealed that distinct frequency bands were correlated with oxygen saturation (6.4–8 Hz and 13–14.4 Hz) and breathing variables (AHI, ODI; 0.8–4.6 Hz).ConclusionsThe correlation between SWA and AHI/ODI suggests that respiratory disturbances contribute to the reduction in SWA at altitude. Since SWA is a marker of sleep homeostasis, this might be indicative of an inability to efficiently dissipate sleep pressure.

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Effects of Acute Exposure to Moderate Altitude on Vascular Function, Metabolism and Systemic Inflammation

Cited by 24 publications

References 32 publications

Dynamic microvesicle release and clearance within the cardiovascular system: triggers and mechanisms

Dynamic microvesicle release and clearance within the cardiovascular system: triggers and mechanisms

Impaired Postural Control in Healthy Men at Moderate Altitude (1630 M and 2590 M): Data from a Randomized Trial

Quantitative Changes in the Sleep EEG at Moderate Altitude (1630 m and 2590 m)

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