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Daily Chronic Intermittent Hypobaric Hypoxia Does Not Induce Chronic Increase in Pulmonary Arterial Pressure Assessed by Echocardiography.

ABSTRACT: Chronic hypoxia causes pulmonary vascular remodeling resulting in persistently increased pulmonary arterial pressures (PAP) even after return to normoxia. Recently, interest in chronic intermittent hypobaric hypoxia (CIHH) was raised because it occurs in subjects working at high altitude (HA) but living in lowland. However, effects of daily CIHH on PAP are unknown. In this pilot study, we included 8 healthy subjects working at (2650?m) each workday for 8-9?h while living and sleeping at LA and 8 matched control subjects living and working at LA. Cardiorespiratory measurements including echocardiography at rest and during exercise were performed at LA (Munich, 530?m) and HA (Zugspitze, 2650?m). Hemoglobin was higher in CIHH subjects. LA echocardiography showed normal right and left cardiac dimensions and function in all subjects. Systolic PAP (sPAP) and tricuspid annular plane systolic excursion (TAPSE) at rest were similar in both groups. Resting blood gas analysis (BGA) at HA revealed decreased pCO2 in CIHH compared to controls (HA: 28.4 versus 31.7?mmHg, p=0.01). During exercise, sPAP was lower in CIHH subjects compared to controls (LA: 28.7 versus 35.3?mmHg, p=0.02; HA: 26.3 versus 33.6?mmHg, p=0.04) and peripheral oxygen saturation (SpO2) was higher. In sum, subjects exposed to CIHH showed no signs of pulmonary vascular remodeling.

SUBMITTER: Gotschke J

PROVIDER: S-EPMC5902055 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Daily Chronic Intermittent Hypobaric Hypoxia Does Not Induce Chronic Increase in Pulmonary Arterial Pressure Assessed by Echocardiography.

Götschke Jeremias J Mertsch Pontus P Kneidinger Nikolaus N Kauffmann-Guerrero Diego D Behr Jürgen J Huber Rudolf Maria RM Reichenberger Frank F Milger Katrin K

Canadian respiratory journal 20180401

Chronic hypoxia causes pulmonary vascular remodeling resulting in persistently increased pulmonary arterial pressures (PAP) even after return to normoxia. Recently, interest in chronic intermittent hypobaric hypoxia (CIHH) was raised because it occurs in subjects working at high altitude (HA) but living in lowland. However, effects of daily CIHH on PAP are unknown. In this pilot study, we included 8 healthy subjects working at (2650 m) each workday for 8-9 h while living and sleeping at LA and 8 ...[more]

PMID: 29808103

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Project description:Over the past 40 years, mining activities in Chile have relocated miners who normally live at sea level to work at high altitudes. This results in a form of chronic intermittent hypobaric hypoxia (CIHH) characterized by alternating periods of work at high altitude and rest periods at sea level. Previous studies performed in our laboratory showed that aerobic capacity is reduced at 3,800 m, even when oxygen content is maintained. Our study aimed to determine the corporal composition, food intake, maximum oxygen uptake, and concentration of high sensitivity C reactive protein (hsCRP) in an acclimatized miner population that work from 0 to 2,500 m with CIHH exposure over 4 years. All miners recruited for our study were operators of heavy trucks with CIHH for over 4 years (shiftwork 7*7 days), and our experimental population was composed of 54 miners at sea level, 61 at 1,600 m, and 38 at 2,500 m. All evaluations were performed on the 3rd or 4th day of diurnal shiftwork. To determine corporal composition, we measured weight and height (to calculate body mass index, BMI), skinfolds (to calculate body fatty, BF), and waist circumference (WC); maximal aerobic capacity was evaluated using a ramp-incremental cycling to exhaustion protocol and a venous blood sample before the exercise test to measure (hsCRP) via an ELISA test. We found higher values of BMI, BF, and WC, in the miners' population but observed no significant difference between populations. We found a decrease in VO2 of 11.6% at 1,600 m and 25.9% at 2,500 m compared to miners at sea level. An increase in (hsCRP) at 1,600 and 2,500 m regards sea level. We observed a high prevalence of overweight and obese subjects, which was related to the ad libitum availability of food and low physical activity (sedentarism). We found that work capacity was maintained despite a decreased VO2 max at moderate altitude. However, overweight and obesity support an increased risk of cardiometabolic disease in miner's which is unrelated to altitude. In contrast, an increased hsCRP level could be associated with increased inflammatory mechanisms at 1,600 and 2,500 m.

Project description:Background: Moderate hypobaric hypoxia induces cerebral ischemic tolerance. We investigated the optimal method for applying hypobaric hypoxia preconditioning at 5,000 m to ischemic brain tissue and combined it with proteomics to determine the mechanisms underlying this effect. Methods: Male SD rats were randomly grouped as S (sham, n = 20), M (middle cerebral artery occlusion [MCAO], n = 28), H2M (intermittent hypobaric hypoxia preconditioned MCAO group, 2 h/day, 10 days, n = 20), H6M (intermittent hypobaric hypoxia preconditioned MCAO group, 6 h/day, 10 days, n = 28), and HpM (persistent hypobaric hypoxia preconditioned MCAO group, 10 days, n = 28). The permanent MCAO model was established based on the Zea Longa method. Infarction was assessed with the modified neurological severity score (mNSS) and 2,3,5-triphenyl tetrazolium chloride staining. The total protein expression of the neuron-specific nuclear protein (NeuN), cysteinyl aspartate specific proteinase 3 (caspase-3), cleaved-caspase-3, and interleukin 6 (IL-6) was determined using western blotting. We assessed the peri-infarct cortex's ultrastructural changes. A label-free proteomic study and western blot verification were performed on the most effective preconditioned group. Results: The H6M group showed a lower infarct volume (p = 0.0005), lower mNSS score (p = 0.0009) than the M group. The H2M showed a lower level of IL-6 (p = 0.0213) than the M group. The caspase-3 level decreased in the H2M (p = 0.0002), H6M (p = 0.0025), and HpM groups (p = 0.0054) compared with that in the M group. Cleaved-caspase-3 expression decreased in the H2M (p = 0.0011), H6M (p < 0.0001), and HpM groups (p < 0.0001) compared with that in the M group. The neurons' ultrastructure and the blood-brain barrier in the peri-infarct tissue improved in the H2M and H6M groups. Immunofluorescence revealed increased NeuN-positive cells in the peri-infarct tissue in the H6M group (p = 0.0003, H6M vs. M). Protein expression of Chmp1a, Arpc5, and Hspa2 factors related to endocytosis were upregulated in the H6M compared with those of the M group (p < 0.05 for all) on western blot verification of label-free proteomics. Conclusions: Intermittent hypobaric hypoxia preconditioning exerts a neuroprotective effect in a rat stroke model. Persistent hypobaric hypoxia stimulation exhibited no significant neuroprotective effect. Intermittent hypoxic preconditioning for 6 h/day for 10 days upregulates key proteins in clathrin-dependent endocytosis of neurons in the cortex.

Dataset Information

Daily Chronic Intermittent Hypobaric Hypoxia Does Not Induce Chronic Increase in Pulmonary Arterial Pressure Assessed by Echocardiography.

Publications

Daily Chronic Intermittent Hypobaric Hypoxia Does Not Induce Chronic Increase in Pulmonary Arterial Pressure Assessed by Echocardiography.

Similar Datasets

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