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Debevec T, Poussel M, Osredkar D, Willis SJ, Sartori C, Millet GP. Post-exercise accumulation of interstitial lung water is greater in hypobaric than normobaric hypoxia in adults born prematurely. Respir Physiol Neurobiol 2021; 297:103828. [PMID: 34890833 DOI: 10.1016/j.resp.2021.103828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 11/24/2021] [Accepted: 12/05/2021] [Indexed: 10/19/2022]
Abstract
We aimed to gauge the interstitial lung water accumulation following moderate-intensity exercise under normobaric and hypobaric hypoxic conditions in a group of preterm born but otherwise healthy young adults. Sixteen pre-term-born individuals (age = 21±2yrs.; gestational age = 29±3wk.; birth weight = 1160±273 g) underwent two 8 -h hypoxic/altitude exposures in a cross-over manner: 1) Normobaric hypoxic exposure (NH; FIO2 = 0.142±0.001; PIO2 = 90.6±0.9 mmHg) 2) Hypobaric hypoxic exposure (HH; terrestrial high-altitude 3840 m; PIO2 = 90.2±0.5 mmHg). Interstitial lung water was assessed via quantification of B-Lines (using lung ultrasound) before (normoxia) and after 4-h and 8-h of respective exposures. At each time point, B-Lines were quantified before (Pre) and immediately after (Post) a 6-min moderate-intensity exercise. The baseline B-lines count were comparable between both conditions (P = 0.191). A higher B-lines count was noted at Pre-H4 in HH versus NH (P = 0.0420). At Post-H8 B-lines score was significantly higher in HH (4.6 ± 1.6) than in NH (3.1 ± 1.4; P = 0.0073). Furthermore, at this time point, a significantly higher number of individuals with B-line scores ≥5 was observed in HH (n = 7) than in NH (n = 3; P = 0.0420). These findings suggest that short moderate-intensity exercise provokes a significant increase in the interstitial lung water accumulation after 8 h of exposure to terrestrial but not simulated altitude (≈3840 m) in prematurely born adults. Further work is needed to elucidate the exact mechanisms of (moderate-intensity) exercise-induced interstitial lung water accumulation in this population and directly compare the obtained data to full-term born adults.
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Affiliation(s)
- Tadej Debevec
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.
| | - Mathias Poussel
- Department of Pulmonary Function Testing and Exercise Physiology, CHRU de Nancy, Nancy, France; Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Damjan Osredkar
- Department of Pediatric Neurology, University Children's Hospital Ljubljana, Ljubljana, Slovenia
| | - Sarah J Willis
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Claudio Sartori
- Department of Internal Medicine and the Botnar Center for Extreme Medicine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Grimmer B, Krauszman A, Hu X, Kabir G, Connelly KA, Li M, Grune J, Madry C, Isakson BE, Kuebler WM. Pannexin 1-a novel regulator of acute hypoxic pulmonary vasoconstriction. Cardiovasc Res 2021; 118:2535-2547. [PMID: 34668529 DOI: 10.1093/cvr/cvab326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 09/08/2021] [Indexed: 12/16/2022] Open
Abstract
AIMS Hypoxic pulmonary vasoconstriction (HPV) is a physiological response to alveolar hypoxia that diverts blood flow from poorly ventilated to better aerated lung areas to optimize ventilation-perfusion matching. Yet, the exact sensory and signaling mechanisms by which hypoxia triggers pulmonary vasoconstriction remain incompletely understood. Recently, ATP release via pannexin 1 (Panx1) and subsequent signaling via purinergic P2Y receptors has been identified as regulator of vasoconstriction in systemic arterioles. Here, we probed for the role of Panx1-mediated ATP release in HPV and chronic hypoxic pulmonary hypertension (PH). METHODS AND RESULTS Pharmacological inhibition of Panx1 by probenecid, spironolactone, the Panx1 specific inhibitory peptide (10Panx1) and genetic deletion of Panx1 specifically in smooth muscle attenuated HPV in isolated perfused mouse lungs. In pulmonary artery smooth muscle cells (PASMC), both spironolactone and 10Panx1 attenuated the increase in intracellular Ca2+ concentration ([Ca2+]i) in response to hypoxia. Yet, genetic deletion of Panx1 in either endothelial or smooth muscle cells did not prevent the development of PH in mice. Unexpectedly, ATP release in response to hypoxia was not detectable in PASMC, and inhibition of purinergic receptors or ATP degradation by ATPase failed to attenuate HPV. Rather, transient receptor potential vanilloid 4 (TRPV4) antagonism and Panx1 inhibition inhibited the hypoxia-induced [Ca2+]i increase in PASMC in an additive manner, suggesting that Panx1 regulates [Ca2+]i independently of the ATP-P2Y-TRPV4 pathway. In line with this notion, Panx1 overexpression increased the [Ca2+]i response to hypoxia in HeLa cells. CONCLUSION In the present study we identify Panx1 as novel regulator of HPV. Yet, the role of Panx1 in HPV was not attributable to ATP release and downstream signaling via P2Y receptors or TRPV4 activation, but relates to a role of Panx1 as direct or indirect modulator of the PASMC Ca2+ response to hypoxia. Panx1 did not affect the development of chronic hypoxic PH. TRANSLATIONAL PERSPECTIVE Hypoxic pulmonary vasoconstriction (HPV) optimizes lung ventilation-perfusion matching, but also contributes to pulmonary pathologies including high altitude pulmonary edema (HAPE) or chronic hypoxic pulmonary hypertension. Here, we demonstrate that pharmaceutical inhibition as well as genetic deletion of the hemichannel pannexin-1 (Panx1) in pulmonary artery smooth muscle cells attenuates the physiological HPV response. Panx1 deficiency did, however, not prevent the development of chronic hypoxic pulmonary hypertension in mice. Panx1 inhibitors such as the mineralocorticoid receptor antagonist spironolactone may thus present a putative strategy for the prevention or treatment of HAPE, yet not for chronic hypoxic lung disease.
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Affiliation(s)
- Benjamin Grimmer
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany.,German Center for Cardiovascular Research (DZHK)
| | - Adrienn Krauszman
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Xudong Hu
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Golam Kabir
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Kim A Connelly
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Mei Li
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Jana Grune
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Christian Madry
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany.,German Center for Cardiovascular Research (DZHK).,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Departments of Physiology and Surgery, University of Toronto, ON, Canada
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53
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Appelt P, Gabriel P, Bölter C, Fiedler N, Schierle K, Salameh A, Rassler B. Left ventricular depression and pulmonary edema in rats after short-term normobaric hypoxia: effects of adrenergic blockade and reduced fluid load. Pflugers Arch 2021; 473:1723-1735. [PMID: 34510286 PMCID: PMC8528748 DOI: 10.1007/s00424-021-02618-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/13/2021] [Accepted: 08/25/2021] [Indexed: 12/25/2022]
Abstract
Acute normobaric hypoxia may induce pulmonary injury with edema (PE) and inflammation. Hypoxia is accompanied by sympathetic activation. As both acute hypoxia and high plasma catecholamine levels may elicit PE, we had originally expected that adrenergic blockade may attenuate the severity of hypoxic pulmonary injury. In particular, we investigated whether administration of drugs with reduced fluid load would be beneficial with respect to both cardiocirculatory and pulmonary functions in acute hypoxia. Rats were exposed to normobaric hypoxia (10% O2) over 1.5 or 6 h and received 0.9% NaCl or adrenergic blockers either as infusion (1 ml/h, increased fluid load) or injection (0.5 ml, reduced fluid load). Control animals were kept in normoxia and received infusions or injections of 0.9% NaCl. After 6 h of hypoxia, LV inotropic function was maintained with NaCl injection but decreased significantly with NaCl infusion. Adrenergic blockade induced a similar LV depression when fluid load was low, but did not further deteriorate LV depression after 6 h of infusion. Reduced fluid load also attenuated pulmonary injury after 6 h of hypoxia. This might be due to an effective fluid drainage into the pleural space. Adrenergic blockade could not prevent PE. In general, increased fluid load and impaired LV inotropic function promote the development of PE in acute hypoxia. The main physiologic conclusion from this study is that fluid reduction under hypoxic conditions has a protective effect on cardiopulmonary function. Consequently, appropriate fluid management has particular importance to subjects in hypoxic conditions.
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Affiliation(s)
- Peter Appelt
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Leipzig, Germany
| | - Philipp Gabriel
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Leipzig, Germany
| | - Christian Bölter
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Leipzig, Germany
| | - Nicole Fiedler
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Leipzig, Germany
| | - Katrin Schierle
- Institute of Pathology, University of Leipzig, Leipzig, Germany
| | - Aida Salameh
- Department of Pediatric Cardiology, Heart Centre, University of Leipzig, Leipzig, Germany
| | - Beate Rassler
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Leipzig, Germany.
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54
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Taçoy G. Congenital heart disease and air travel. Anatol J Cardiol 2021; 25:18-19. [PMID: 34464294 DOI: 10.5152/anatoljcardiol.2021.s107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The number of individuals traveling by airplanes is increasing every year. Patients with congenital heart disease and shunts, exposure to high altitude during a flight is important since it causes pulmonary vaso- constriction leading to an increase in right-to-left shunting and a decrease in arterial oxygen saturation. Patients with cyanotic congenital heart disease and Eisenmenger syndrome should be evaluated before the flight, and necessary precautions should be taken.
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Affiliation(s)
- Gülten Taçoy
- Department of Cardiology, Faculty of Medicine, Gazi University; Ankara-Turkey
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55
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Implication of Blood Rheology and Pulmonary Hemodynamics on Exercise-Induced Hypoxemia at Sea Level and Altitude in Athletes. Int J Sport Nutr Exerc Metab 2021; 31:397-405. [PMID: 34303308 DOI: 10.1123/ijsnem.2021-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 11/18/2022]
Abstract
This study aimed to investigate the changes in blood viscosity, pulmonary hemodynamics, nitric oxide (NO) production, and maximal oxygen uptake (V˙O2max) during a maximal incremental test conducted in normoxia and during exposure to moderate altitude (2,400 m) in athletes exhibiting exercise-induced hypoxemia at sea level (EIH). Nine endurance athletes with EIH and eight without EIH (NEIH) performed a maximal incremental test under three conditions: sea level, 1 day after arrival in hypoxia, and 5 days after arrival in hypoxia (H5) at 2,400 m. Gas exchange and oxygen peripheral saturation (SpO2) were continuously monitored. Cardiac output, pulmonary arterial pressure, and total pulmonary vascular resistance were assessed by echocardiography. Venous blood was sampled before and 3 min after exercise cessation to analyze blood viscosity and NO end-products. At sea level, athletes with EIH exhibited an increase in blood viscosity and NO levels during exercise while NEIH athletes showed no change. Pulmonary hemodynamics and aerobic performance were not different between the two groups. No between-group differences in blood viscosity, pulmonary hemodynamics, and V˙O2max were found at 1 day after arrival in hypoxia. At H5, lower total pulmonary vascular resistance and greater NO concentration were reported in response to exercise in EIH compared with NEIH athletes. EIH athletes had greater cardiac output and lower SpO2 at maximal exercise in H5, but no between-group differences occurred regarding blood viscosity and V˙O2max. The pulmonary vascular response observed at H5 in EIH athletes may be involved in the greater cardiac output of EIH group and counterbalanced the drop in SpO2 in order to achieve similar V˙O2max than NEIH athletes.
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56
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Lichtblau M, Berlier C, Saxer S, Carta AF, Mayer L, Groth A, Bader PR, Schneider SR, Furian M, Schwarz EI, Swenson ER, Bloch KE, Ulrich S. Acute Hemodynamic Effect of Acetazolamide in Patients With Pulmonary Hypertension Whilst Breathing Normoxic and Hypoxic Gas: A Randomized Cross-Over Trial. Front Med (Lausanne) 2021; 8:681473. [PMID: 34368187 PMCID: PMC8341560 DOI: 10.3389/fmed.2021.681473] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/24/2021] [Indexed: 01/30/2023] Open
Abstract
Aims: To test the acute hemodynamic effect of acetazolamide in patients with pulmonary hypertension (PH) under ambient air and hypoxia. Methods: Patients with pulmonary arterial or chronic thromboembolic PH (PAH/CTEPH) undergoing right heart catheterization were included in this randomized, placebo-controlled, double-blinded, crossover trial. The main outcome, pulmonary vascular resistance (PVR), further hemodynamics, blood- and cerebral oxygenation were measured 1 h after intravenous administration of 500 mg acetazolamide or placebo-saline on ambient air (normoxia) and at the end of breathing hypoxic gas (FIO2 0.15, hypoxia) for 15 min. Results: 24 PH-patients, 71% men, mean ± SD age 59 ± 14 years, BMI 28 ± 5 kg/m2, PVR 4.7 ± 2.1 WU participated. Mean PVR after acetazolamide vs. placebo was 5.5 ± 3.0 vs. 5.3 ± 3.0 WU; mean difference (95% CI) 0.2 (−0.2–0.6, p = 0.341). Heart rate was higher after acetazolamide (79 ± 12 vs. 77 ± 11 bpm, p = 0.026), pH was lower (7.40 ± 0.02 vs. 7.42 ± 0.03, p = 0.002) but PaCO2 and PaO2 remained unchanged while cerebral tissue oxygenation increased (71 ± 6 vs. 69 ± 6%, p = 0.017). In acute hypoxia, acetazolamide decreased PVR by 0.4 WU (0.0–0.9, p = 0.046) while PaO2 and PaCO2 were not changed. No adverse effects occurred. Conclusions: In patients with PAH/CTEPH, i.v. acetazolamide did not change pulmonary hemodynamics compared to placebo after 1 hour in normoxia but it reduced PVR after subsequent acute exposure to hypoxia. Our findings in normoxia do not suggest a direct acute pulmonary vasodilator effect of acetazolamide. The reduction of PVR during hypoxia requires further corroboration. Whether acetazolamide improves PH when given over a prolonged period by stimulating ventilation, increasing oxygenation, and/or altering vascular inflammation and remodeling remains to be investigated.
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Affiliation(s)
- Mona Lichtblau
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Charlotte Berlier
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Stéphanie Saxer
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Arcangelo F Carta
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Laura Mayer
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Alexandra Groth
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Patrick R Bader
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Simon R Schneider
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Michael Furian
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Esther I Schwarz
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Erik R Swenson
- Division of Pulmonary, Critical Care and Sleep Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA, United States
| | - Konrad E Bloch
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Silvia Ulrich
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
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57
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Zubieta-Calleja G, Zubieta-DeUrioste N. The Oxygen Transport Triad in High-Altitude Pulmonary Edema: A Perspective from the High Andes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:7619. [PMID: 34300070 PMCID: PMC8305285 DOI: 10.3390/ijerph18147619] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 12/24/2022]
Abstract
Acute high-altitude illnesses are of great concern for physicians and people traveling to high altitude. Our recent article "Acute Mountain Sickness, High-Altitude Pulmonary Edema and High-Altitude Cerebral Edema, a View from the High Andes" was questioned by some sea-level high-altitude experts. As a result of this, we answer some observations and further explain our opinion on these diseases. High-Altitude Pulmonary Edema (HAPE) can be better understood through the Oxygen Transport Triad, which involves the pneumo-dynamic pump (ventilation), the hemo-dynamic pump (heart and circulation), and hemoglobin. The two pumps are the first physiologic response upon initial exposure to hypobaric hypoxia. Hemoglobin is the balancing energy-saving time-evolving equilibrating factor. The acid-base balance must be adequately interpreted using the high-altitude Van Slyke correction factors. Pulse-oximetry measurements during breath-holding at high altitude allow for the evaluation of high altitude diseases. The Tolerance to Hypoxia Formula shows that, paradoxically, the higher the altitude, the more tolerance to hypoxia. In order to survive, all organisms adapt physiologically and optimally to the high-altitude environment, and there cannot be any "loss of adaptation". A favorable evolution in HAPE and pulmonary hypertension can result from the oxygen treatment along with other measures.
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Affiliation(s)
- Gustavo Zubieta-Calleja
- High Altitude Pulmonary and Pathology Institute (HAPPI-IPPA), Av. Copacabana Prolongacion #55, La Paz 2826, Bolivia;
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58
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Lepper PM, Radermacher P, Steinacker JM, Fischer R, Bals R. Grannemann JJ, Roper A. Aufenthalte in großen Höhen nach COVID-19-Infektion – neue Aspekte der höhenmedizinischen Beratung. Pneumologie 2021, 75: 214–220. Pneumologie 2021; 75:474-476. [PMID: 34116578 DOI: 10.1055/a-1479-1322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Philipp M Lepper
- Klinik für Innere Medizin V - Pneumologie, Allergologie und Intensivmedizin, Universitätskliniken des Saarlandes, Homburg/Saar
| | - Peter Radermacher
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Ulm
| | | | - Rainald Fischer
- Lungenheilkunde München-Pasing, Gleichmannstraße 5, München-Pasing
| | - Robert Bals
- Klinik für Innere Medizin V - Pneumologie, Allergologie und Intensivmedizin, Universitätskliniken des Saarlandes, Homburg/Saar
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59
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Sharma K, Mishra A, Singh HN, Prashar D, Alam P, Thinlas T, Mohammad G, Kukreti R, Syed MA, Pasha MAQ. High-altitude pulmonary edema is aggravated by risk-loci and associated transcription factors in HIF-prolyl hydroxylases. Hum Mol Genet 2021; 30:1734-1749. [PMID: 34007987 DOI: 10.1093/hmg/ddab139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 11/15/2022] Open
Abstract
High-altitude (HA, > 2500 meters) hypoxic exposure evokes several physiological processes that may be abetted by differential genetic distribution in sojourners, who are susceptible to various HA disorders, such as high-altitude pulmonary edema (HAPE). The genetic variants in hypoxia-sensing genes influence the transcriptional output, however the functional role has not been investigated in HAPE. This study explored the two hypoxia-sensing genes, prolyl hydroxylase domain protein 2 (EGLN1) and factor inhibiting HIF-1α (HIF1AN) in HA adaptation and maladaptation in three well-characterized groups: highland natives, HAPE-free controls and HAPE-patients. The two genes were sequenced and subsequently validated through genotyping of significant SNPs, haplotyping and MDR. Three EGLN1 SNPs rs1538664, rs479200 and rs480902 and their haplotypes emerged significant in HAPE. Blood gene expression and protein levels also differed significantly (P < 0.05) and correlated with clinical parameters and respective alleles. The RegulomeDB annotation exercises of the loci corroborated regulatory role. Allele-specific differential expression was evidenced by luciferase assay followed by electrophoretic mobility shift assay, LC-MS/MS and supershift assays, which confirmed allele-specific transcription factor (TF) binding of FUS RNA binding protein (FUS) with rs1538664A, Rho GDP dissociation inhibitor 1 (RhoGDH1) with rs479200T and Hypoxia up-regulated protein 1 (HYOU1) with rs480902C. Docking simulation studies were in sync for the DNA-TF structural variations. There was strong networking among the TFs that revealed physiological consequences through relevant pathways. The two hydroxylases appear crucial in the regulation of hypoxia-inducible responses.
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Affiliation(s)
- Kavita Sharma
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, 110007, India.,Department of Biotechnology, Jamia Millia Islamia, New Delhi, 110025, India
| | - Aastha Mishra
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, 110007, India
| | - Himanshu N Singh
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, 110007, India
| | - Deepak Prashar
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, 110007, India
| | - Perwez Alam
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, 110007, India.,Department of Pathology and Laboratory Medicine, College of Medicine, University of Cincinnati, OH, USA
| | | | | | - Ritushree Kukreti
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, 110007, India
| | - Mansoor Ali Syed
- Department of Biotechnology, Jamia Millia Islamia, New Delhi, 110025, India
| | - M A Qadar Pasha
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, 110007, India.,Indian Council of Medical Research, New Delhi, 110029, India
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60
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West CM, Wearing OH, Rhem RG, Scott GR. Pulmonary hypertension is attenuated and ventilation-perfusion matching is maintained during chronic hypoxia in deer mice native to high altitude. Am J Physiol Regul Integr Comp Physiol 2021; 320:R800-R811. [PMID: 33826424 DOI: 10.1152/ajpregu.00282.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hypoxia at high altitude can constrain metabolism and performance and can elicit physiological adjustments that are deleterious to health and fitness. Hypoxic pulmonary hypertension is a particularly serious and maladaptive response to chronic hypoxia, which results from vasoconstriction and pathological remodeling of pulmonary arteries, and can lead to pulmonary edema and right ventricle hypertrophy. We investigated whether deer mice (Peromyscus maniculatus) native to high altitude have attenuated this maladaptive response to chronic hypoxia and whether evolved changes or hypoxia-induced plasticity in pulmonary vasculature might impact ventilation-perfusion (V-Q) matching in chronic hypoxia. Deer mouse populations from both high and low altitudes were born and raised to adulthood in captivity at sea level, and various aspects of lung function were measured before and after exposure to chronic hypoxia (12 kPa O2, simulating the O2 pressure at 4,300 m) for 6-8 wk. In lowlanders, chronic hypoxia increased right ventricle systolic pressure (RVSP) from 14 to 19 mmHg (P = 0.001), in association with thickening of smooth muscle in pulmonary arteries and right ventricle hypertrophy. Chronic hypoxia also impaired V-Q matching in lowlanders (measured at rest using SPECT-CT imaging), as reflected by increased log SD of the perfusion distribution (log SDQ) from 0.55 to 0.86 (P = 0.031). In highlanders, chronic hypoxia had attenuated effects on RVSP and no effects on smooth muscle thickness, right ventricle mass, or V-Q matching. Therefore, evolved changes in lung function help attenuate maladaptive plasticity and contribute to hypoxia tolerance in high-altitude deer mice.
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Affiliation(s)
- Claire M West
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Oliver H Wearing
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Rod G Rhem
- Division of Respirology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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61
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Lichtblau M, Bader PR, Carta AF, Furian M, Muralt L, Saxer S, Hartmann SE, Rawling JM, Poulin MJ, Bloch KE, Ulrich S. Extravascular lung water and cardiac function assessed by echocardiography in healthy lowlanders during repeated very high-altitude exposure. Int J Cardiol 2021; 332:166-174. [PMID: 33775791 DOI: 10.1016/j.ijcard.2021.03.057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/05/2021] [Accepted: 03/22/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND High-altitude pulmonary edema is associated with elevated systolic pulmonary artery pressure (sPAP) and increased extravascular lung water (EVLW). We investigated sPAP and EVLW during repeated exposures to high altitude (HA). METHODS Healthy lowlanders underwent two identical 7-day HA-cycles, where subjects slept at 2900 m and spent 4-8 h daily at 5050 m, separated by a weeklong break at low altitude (LA). Echocardiography and EVLW by B-lines were measured at 520 m (baseline, LA1), on day one, two and six at 5050 m (HA1-3) and after descent (LA2). RESULTS We included 21 subjects (median 25 years, body mass index 22 kg/m2, SpO2 98%). SPAP rose from 21 mmHg at LA1 to 38 mmHg at HA1, decreased to 30 mmHg at HA3 (both p < 0.05 vs LA1) and normalized at 20 mmHg at LA2 (p = ns vs LA1). B-lines increased from 0 at LA1 to 6 at HA2 and 7 at HA3 (both p < 0.05 vs LA1) and receded to 1 at LA2 (p = ns vs LA1). Overall, in cycle two, sPAP did not differ (mean difference (95% confidence interval) -0.2(-2.3 to 1.9) mmHg, p = 0.864) but B-lines were more prevalent (+2.3 (1.4-3.1), p < 0.001) compared to cycle 1. Right ventricular systolic function decreased significantly but minimally at 5050 m. CONCLUSIONS Exposure to 5050 m induced a rapid increase in sPAP. B-lines rose during prolonged exposures to 5050 m, despite gradual decrease in sPAP, indicating excessive hydrostatic pressure might not be solely responsible for EVLW-development. Repeated HA-exposure had no acclimatization effect on EVLW. This may affect workers needing repetitive ascents to altitude and could indicate greater B-line development upon repeated exposure.
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Affiliation(s)
- Mona Lichtblau
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.
| | - Patrick R Bader
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.
| | - Arcangelo F Carta
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.
| | - Michael Furian
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.
| | - Lara Muralt
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Stéphanie Saxer
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.
| | - Sara E Hartmann
- Department of Physiology and Pharmacology and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
| | - Jean M Rawling
- Department of Family Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
| | - Marc J Poulin
- Department of Physiology and Pharmacology and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
| | - Konrad E Bloch
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.
| | - Silvia Ulrich
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.
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62
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Pulmonary Hypertension in Acute and Chronic High Altitude Maladaptation Disorders. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041692. [PMID: 33578749 PMCID: PMC7916528 DOI: 10.3390/ijerph18041692] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/13/2022]
Abstract
Alveolar hypoxia is the most prominent feature of high altitude environment with well-known consequences for the cardio-pulmonary system, including development of pulmonary hypertension. Pulmonary hypertension due to an exaggerated hypoxic pulmonary vasoconstriction contributes to high altitude pulmonary edema (HAPE), a life-threatening disorder, occurring at high altitudes in non-acclimatized healthy individuals. Despite a strong physiologic rationale for using vasodilators for prevention and treatment of HAPE, no systematic studies of their efficacy have been conducted to date. Calcium-channel blockers are currently recommended for drug prophylaxis in high-risk individuals with a clear history of recurrent HAPE based on the extensive clinical experience with nifedipine in HAPE prevention in susceptible individuals. Chronic exposure to hypoxia induces pulmonary vascular remodeling and development of pulmonary hypertension, which places an increased pressure load on the right ventricle leading to right heart failure. Further, pulmonary hypertension along with excessive erythrocytosis may complicate chronic mountain sickness, another high altitude maladaptation disorder. Importantly, other causes than hypoxia may potentially underlie and/or contribute to pulmonary hypertension at high altitude, such as chronic heart and lung diseases, thrombotic or embolic diseases. Extensive clinical experience with drugs in patients with pulmonary arterial hypertension suggests their potential for treatment of high altitude pulmonary hypertension. Small studies have demonstrated their efficacy in reducing pulmonary artery pressure in high altitude residents. However, no drugs have been approved to date for the therapy of chronic high altitude pulmonary hypertension. This work provides a literature review on the role of pulmonary hypertension in the pathogenesis of acute and chronic high altitude maladaptation disorders and summarizes current knowledge regarding potential treatment options.
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63
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Lucas SJE, Malein WL, Thomas OD, Ashdown KM, Rue CA, Joyce KE, Newman C, Cadigan P, Johnson B, Myers SD, Myers FA, Wright AD, Delamere J, Imray CHE, Bradwell AR, Edsell M. Effect of losartan on performance and physiological responses to exercise at high altitude (5035 m). BMJ Open Sport Exerc Med 2021; 7:e000982. [PMID: 33489310 PMCID: PMC7797254 DOI: 10.1136/bmjsem-2020-000982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2020] [Indexed: 12/15/2022] Open
Abstract
Objective Altitude-related and exercise-related elevations in blood pressure (BP) increase the likelihood of developing pulmonary hypertension and high-altitude illness during high-altitude sojourn. This study examined the antihypertensive effect and potential exercise benefit of the angiotensin II receptor antagonist losartan when taken at altitude. Methods Twenty participants, paired for age and ACE genotype status, completed a double-blinded, randomised study, where participants took either losartan (100 mg/day) or placebo for 21 days prior to arrival at 5035 m (Whymper Hut, Mt Chimborazo, Ecuador). Participants completed a maximal exercise test on a supine cycle ergometer at sea level (4 weeks prior) and within 48 hours of arrival to 5035 m (10-day ascent). Power output, beat-to-beat BP, oxygen saturation (SpO2) and heart rate (HR) were recorded during exercise, with resting BP collected from daily medicals during ascent. Before and immediately following exercise at 5035 m, extravascular lung water prevalence was assessed with ultrasound (quantified via B-line count). Results At altitude, peak power was reduced relative to sea level (p<0.01) in both groups (losartan vs placebo: down 100±29 vs 91±28 W, p=0.55), while SpO2 (70±6 vs 70±5%, p=0.96) and HR (146±21 vs 149±24 bpm, p=0.78) were similar between groups at peak power, as was the increase in systolic BP from rest to peak power (up 80±37 vs 69±33 mm Hg, p=0.56). Exercise increased B-line count (p<0.05), but not differently between groups (up 5±5 vs 8±10, p=0.44). Conclusion Losartan had no observable effect on resting or exercising BP, exercise-induced symptomology of pulmonary hypertension or performance at 5035 m.
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Affiliation(s)
- Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | | | - Owen D Thomas
- Department of Anaesthesia, Royal Gwent Hospital, Aneurin Bevan University Health Board, Newport, UK
| | - Kimberly M Ashdown
- Occupational Performance Research Group, University of Chichester, Chichester, West Sussex, UK
| | - Carla A Rue
- Occupational Performance Research Group, University of Chichester, Chichester, West Sussex, UK
| | - Kelsey E Joyce
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Charles Newman
- Royal Centre for Defence Medicine, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Patrick Cadigan
- Birmingham Medical Research Expeditionary Society, Birmingham, UK
| | - Brian Johnson
- Birmingham Medical Research Expeditionary Society, Birmingham, UK
| | - Stephen D Myers
- Occupational Performance Research Group, University of Chichester, Chichester, West Sussex, UK
| | - Fiona A Myers
- School of Biological Sciences, University of Portsmouth, Portsmouth, Hampshire, UK
| | | | - John Delamere
- School of Medicine, University of Birmingham, Birmingham, UK
| | - Chris H E Imray
- Department of Vascular Surgery, University Hospitals of Coventry and Warwickshire, Warwick Medical School, University of Warwick, Coventry, UK
| | | | - Mark Edsell
- Department of Anaesthesia, St George's University Hospitals NHS Foundation Trust, London, UK
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64
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Millet GP, Debevec T, Brocherie F, Burtscher M, Burtscher J. Altitude and COVID-19: Friend or foe? A narrative review. Physiol Rep 2021; 8:e14615. [PMID: 33340275 PMCID: PMC7749581 DOI: 10.14814/phy2.14615] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/11/2022] Open
Abstract
Recent reports suggest that high-altitude residence may be beneficial in the novel coronavirus disease (COVID-19) implicating that traveling to high places or using hypoxic conditioning thus could be favorable as well. Physiological high-altitude characteristics and symptoms of altitude illnesses furthermore seem similar to several pathologies associated with COVID-19. As a consequence, high altitude and hypoxia research and related clinical practices are discussed for potential applications in COVID-19 prevention and treatment. We summarize the currently available evidence on the relationship between altitude/hypoxia conditions and COVID-19 epidemiology and pathophysiology. The potential for treatment strategies used for altitude illnesses is evaluated. Symptomatic overlaps in the pathophysiology of COVID-19 induced ARDS and high altitude illnesses (i.e., hypoxemia, dyspnea…) have been reported but are also common to other pathologies (i.e., heart failure, pulmonary embolism, COPD…). Most treatments of altitude illnesses have limited value and may even be detrimental in COVID-19. Some may be efficient, potentially the corticosteroid dexamethasone. Physiological adaptations to altitude/hypoxia can exert diverse effects, depending on the constitution of the target individual and the hypoxic dose. In healthy individuals, they may optimize oxygen supply and increase mitochondrial, antioxidant, and immune system function. It is highly debated if these physiological responses to hypoxia overlap in many instances with SARS-CoV-2 infection and may exert preventive effects under very specific conditions. The temporal overlap of SARS-CoV-2 infection and exposure to altitude/hypoxia may be detrimental. No evidence-based knowledge is presently available on whether and how altitude/hypoxia may prevent, treat or aggravate COVID-19. The reported lower incidence and mortality of COVID-19 in high-altitude places remain to be confirmed. High-altitude illnesses and COVID-19 pathologies exhibit clear pathophysiological differences. While potentially effective as a prophylactic measure, altitude/hypoxia is likely associated with elevated risks for patients with COVID-19. Altogether, the different points discussed in this review are of possibly some relevance for individuals who aim to reach high-altitude areas. However, due to the ever-changing state of understanding of COVID-19, all points discussed in this review may be out of date at the time of its publication.
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Affiliation(s)
| | - Tadej Debevec
- Faculty of SportUniversity of LjubljanaLjubljanaSlovenia
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65
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Chanana N, Palmo T, Newman JH, Pasha MAQ. Vascular homeostasis at high-altitude: role of genetic variants and transcription factors. Pulm Circ 2020; 10:2045894020913475. [PMID: 33282179 PMCID: PMC7682230 DOI: 10.1177/2045894020913475] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/14/2020] [Indexed: 12/24/2022] Open
Abstract
High-altitude pulmonary edema occurs most frequently in non-acclimatized low landers on exposure to altitude ≥2500 m. High-altitude pulmonary edema is a complex condition that involves perturbation of signaling pathways in vasoconstrictors, vasodilators, anti-diuretics, and vascular growth factors. Genetic variations are instrumental in regulating these pathways and evidence is accumulating for a role of epigenetic modification in hypoxic responses. This review focuses on the crosstalk between high-altitude pulmonary edema-associated genetic variants and transcription factors, comparing high-altitude adapted and high-altitude pulmonary edema-afflicted subjects. This approach might ultimately yield biomarker information both to understand and to design therapies for high-altitude adaptation.
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Affiliation(s)
- Neha Chanana
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Tsering Palmo
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - John H Newman
- Pulmonary Circulation Center, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - M A Qadar Pasha
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi, India.,Indian Council of Medical Research, New Delhi, India
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66
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Baloglu E, Nonnenmacher G, Seleninova A, Berg L, Velineni K, Ermis-Kaya E, Mairbäurl H. The role of hypoxia-induced modulation of alveolar epithelial Na +- transport in hypoxemia at high altitude. Pulm Circ 2020; 10:50-58. [PMID: 33110497 PMCID: PMC7557693 DOI: 10.1177/2045894020936662] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/02/2020] [Indexed: 12/14/2022] Open
Abstract
Reabsorption of excess alveolar fluid is driven by vectorial Na+-transport across alveolar epithelium, which protects from alveolar flooding and facilitates gas exchange. Hypoxia inhibits Na+-reabsorption in cultured cells and in-vivo by decreasing activity of epithelial Na+-channels (ENaC), which impairs alveolar fluid clearance. Inhibition also occurs during in-vivo hypoxia in humans and laboratory animals. Signaling mechanisms that inhibit alveolar reabsorption are poorly understood. Because cellular adaptation to hypoxia is regulated by hypoxia-inducible transcription factors (HIF), we tested whether HIFs are involved in decreasing Na+-transport in hypoxic alveolar epithelium. Expression of HIFs was suppressed in cultured rat primary alveolar epithelial cells (AEC) with shRNAs. Hypoxia (1.5% O2, 24 h) decreased amiloride-sensitive transepithelial Na+-transport, decreased the mRNA expression of α-, β-, and γ-ENaC subunits, and reduced the amount of αβγ-ENaC subunits in the apical plasma membrane. Silencing HIF-2α partially prevented impaired fluid reabsorption in hypoxic rats and prevented the hypoxia-induced decrease in α- but not the βγ-subunits of ENaC protein expression resulting in a less active form of ENaC in hypoxic AEC. Inhibition of alveolar reabsorption also caused pulmonary vasoconstriction in ventilated rats. These results indicate that a HIF-2α-dependent decrease in Na+-transport in hypoxic alveolar epithelium decreases alveolar reabsorption. Because susceptibles to high-altitude pulmonary edema (HAPE) have decreased Na+-transport even in normoxia, inhibition of alveolar reabsorption by hypoxia at high altitude might further impair alveolar gas exchange. Thus, aggravated hypoxemia might further enhance hypoxic pulmonary vasoconstriction and might subsequently cause HAPE.
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Affiliation(s)
- Emel Baloglu
- Department of Pharmacology, Acibadem Mehmet Ali Aydinlar University, School of Medicine, Istanbul, Turkey.,Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | | | - Anna Seleninova
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Lena Berg
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Kalpana Velineni
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Ezgi Ermis-Kaya
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Heimo Mairbäurl
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany.,Translational Pneumology, University Hospital Heidelberg, Heidelberg, Germany
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67
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Berger MM, Hackett PH, Bärtsch P. No Relevant Analogy Between COVID-19 and Acute Mountain Sickness. High Alt Med Biol 2020; 21:315-318. [PMID: 32970479 DOI: 10.1089/ham.2020.0147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Berger, Marc Moritz, Peter H. Hackett, and Peter Bärtsch. No relevant analogy between COVID-19 and acute mountain sickness. High Alt Med Biol. 21:315-318, 2020.-Clinicians and scientists have suggested therapies for coronavirus disease-19 (COVID-19) that are known to be effective for other medical conditions. A recent publication suggests that pathophysiological mechanisms underlying acute mountain sickness (a syndrome of nonspecific neurological symptoms typically experienced by nonacclimatized individuals at altitudes >2500 m) may overlap with the mechanisms causing COVID-19. In this short review, we briefly evaluate this mistaken analogy and demonstrate that this concept is not supported by scientific evidence.
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Affiliation(s)
- Marc Moritz Berger
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, Essen, Germany
| | - Peter H Hackett
- Altitude Research Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Peter Bärtsch
- Department of Internal Medicine, University of Heidelberg, Heidelberg, Germany
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68
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Verbrugge FH, Guazzi M, Testani JM, Borlaug BA. Altered Hemodynamics and End-Organ Damage in Heart Failure: Impact on the Lung and Kidney. Circulation 2020; 142:998-1012. [PMID: 32897746 DOI: 10.1161/circulationaha.119.045409] [Citation(s) in RCA: 149] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Heart failure is characterized by pathologic hemodynamic derangements, including elevated cardiac filling pressures ("backward" failure), which may or may not coexist with reduced cardiac output ("forward" failure). Even when normal during unstressed conditions such as rest, hemodynamics classically become abnormal during stressors such as exercise in patients with heart failure. This has important upstream and downstream effects on multiple organ systems, particularly with respect to the lungs and kidneys. Hemodynamic abnormalities in heart failure are affected by processes that extend well beyond the cardiac myocyte, including important roles for pericardial constraint, ventricular interaction, and altered venous capacity. Hemodynamic perturbations have widespread effects across multiple heart failure phenotypes, ranging from reduced to preserved ejection fraction, acute to chronic disease, and cardiogenic shock to preserved perfusion states. In the lung, hemodynamic derangements lead to the development of abnormalities in ventilatory control and efficiency, pulmonary congestion, capillary stress failure, and eventually pulmonary vascular disease. In the kidney, hemodynamic perturbations lead to sodium and water retention and worsening renal function. Improved understanding of the mechanisms by which altered hemodynamics in heart failure affect the lungs and kidneys is needed in order to design novel strategies to improve clinical outcomes.
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Affiliation(s)
- Frederik H Verbrugge
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (F.H.V., B.A.B.).,Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Belgium (F.H.V.)
| | - Marco Guazzi
- Cardiology University Department, Heart Failure Unit, University of Milano, IRCCS Policlinico San Donato, Milan, Italy (M.G.)
| | - Jeffrey M Testani
- Section of Cardiovascular Medicine, Yale University, New Haven, CT (J.M.T.)
| | - Barry A Borlaug
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (F.H.V., B.A.B.)
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69
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COVID-19 Lung Injury and High-Altitude Pulmonary Edema. A False Equation with Dangerous Implications. Ann Am Thorac Soc 2020; 17:918-921. [PMID: 32735170 PMCID: PMC7393782 DOI: 10.1513/annalsats.202004-327cme] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Amid efforts to care for the large number of patients with coronavirus disease (COVID-19), there has been considerable speculation about whether the lung injury seen in these patients is different than acute respiratory distress syndrome from other causes. One idea that has garnered considerable attention, particularly on social media and in free open-access medicine, is the notion that lung injury due to COVID-19 is more similar to high-altitude pulmonary edema (HAPE). Drawing on this concept, it has also been proposed that treatments typically employed in the management of HAPE and other forms of acute altitude illness—pulmonary vasodilators and acetazolamide—should be considered for COVID-19. Despite some similarities in clinical features between the two entities, such as hypoxemia, radiographic opacities, and altered lung compliance, the pathophysiological mechanisms of HAPE and lung injury due to COVID-19 are fundamentally different, and the entities cannot be viewed as equivalent. Although of high utility in the management of HAPE and acute mountain sickness, systemically delivered pulmonary vasodilators and acetazolamide should not be used in the treatment of COVID-19, as they carry the risk of multiple adverse consequences, including worsened ventilation–perfusion matching, impaired carbon dioxide transport, systemic hypotension, and increased work of breathing.
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70
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Strapazzon G, Hilty MP, Bouzat P, Pratali L, Brugger H, Rauch S. To compare the incomparable: COVID-19 pneumonia and high-altitude disease. Eur Respir J 2020; 55:13993003.01362-2020. [PMID: 32398299 PMCID: PMC7315003 DOI: 10.1183/13993003.01362-2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 04/27/2020] [Indexed: 01/16/2023]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic is overwhelming healthcare systems worldwide. There is no evidence from randomised clinical trials that any potential therapy improves outcome in COVID-19 pneumonia, and therapeutic strategies have been based on a progressively increasing knowledge of the clinical presentation of the disease. Some clinicians have found the clinical features of COVID-19 pneumonia to be similar to high-altitude pulmonary oedema (HAPE) [1], and such theory has been amplified via social media. We question this relationship. COVID-19 pneumonia is a viral infection; high-altitude pulmonary oedema is a non-cardiogenic oedema. Some clinicians have found the clinical features similar. It is important to clarify such misconceptions to prevent erroneous treatment strategieshttps://bit.ly/2KOBi3F
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Affiliation(s)
- Giacomo Strapazzon
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy .,Dept of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Innsbruck, Austria
| | - Matthias P Hilty
- Intensive Care Unit, University Hospital of Zurich, Zurich, Switzerland
| | - Pierre Bouzat
- Dept Anaesthesia and Critical Care, University Hospital of Grenoble, Grenoble, France
| | - Lorenza Pratali
- Institute of Clinical Physiology, National Council of Research - CNR, Pisa, Italy
| | - Hermann Brugger
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy.,Dept of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Innsbruck, Austria
| | - Simon Rauch
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy.,Dept of Anesthesia and Intensive Care Medicine, "F. Tappeiner" Hospital, Merano, Italy
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71
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Brugger H, Basnyat B, Ellerton J, Hefti U, Strapazzon G, Zafren K. Letter to the Editor: COVID-19 Lung Injury Is Different From High Altitude Pulmonary Edema. High Alt Med Biol 2020; 21:204-205. [PMID: 32364407 DOI: 10.1089/ham.2020.0061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Hermann Brugger
- Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy.,International Society of Mountain Medicine (President), Switzerland.,Medical University of Innsbruck, Innsbruck, Austria.,International Commission for Alpine Rescue Medical Commission (ICAR MedCom), Zurich, Switzerland
| | - Buddha Basnyat
- Oxford University Clinical Research Unit-Nepal, Himalayan Rescue Association, and Travel and Mountain Medicine Center, Kathmandu, Nepal.,International Society of Mountain Medicine (Past President), Switzerland
| | - John Ellerton
- International Commission for Alpine Rescue Medical Commission (ICAR MedCom) (President), Zurich, Switzerland
| | - Urs Hefti
- Swiss Sportclinic, Bern, Switzerland.,Medical Commission International Climbing and Mountaineering Federation (UIAA) (President), Bern, Switzerland
| | - Giacomo Strapazzon
- Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy.,Medical University of Innsbruck, Innsbruck, Austria.,International Commission for Alpine Rescue Medical Commission (ICAR MedCom), Zurich, Switzerland.,International Society of Mountain Medicine, Switzerland
| | - Ken Zafren
- International Commission for Alpine Rescue Medical Commission (ICAR MedCom), Zurich, Switzerland.,Department of Emergency Medicine, Alaska Native Medical Center, Anchorage, USA.,Department of Emergency Medicine, Stanford University Medical Center, Stanford, USA
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72
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Swenson ER. Early hours in the development of high-altitude pulmonary edema: time course and mechanisms. J Appl Physiol (1985) 2020; 128:1539-1546. [PMID: 32213112 DOI: 10.1152/japplphysiol.00824.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Clinically evident high-altitude pulmonary edema (HAPE) is characterized by severe cyanosis, dyspnea, cough, and difficulty with physical exertion. This usually occurs within 1-2 days of ascent often with the additional stresses of any exercise and hypoventilation of sleep. The earliest events in evolving HAPE progress through clinically silent and then minimally recognized problems. The most important of these events involves an exaggerated elevation of pulmonary artery (PA) pressure in response to the ambient hypoxia. Hypoxic pulmonary vasoconstriction (HPV) is a rapid response with several phases. The first phase in both resistance arterioles and venules occurs within 5-10 min. This is followed by a second phase that further raises PA pressure by another 100% over the next 2-8 h. Combined with vasoconstriction and likely an unevenness in the regional strength of HPV, pressures in some microvascular regions with lesser arterial constriction rise to a level that initiates greater filtration of fluid into the interstitium. As pressures continue to rise local lymphatic clearance rates are exceeded and interstitial fluid begins to accumulate. Beyond elevation of transmural pressure gradients there is a dynamic noninjurious relaxation of microvascular and epithelial cell-cell contacts and an increase in transcellular vesicular transport which accelerate leakage. At some point with further pressure elevation, damage occurs with breaks of the barrier and bleeding into the alveolar space, a late-stage situation termed capillary stress failure. Earlier before there is fluid accumulation, alveolar hypoxia and hyperventilation-induced hypocapnia reduce the capacity of the alveolar epithelium to reabsorb sodium and water back into the interstitial space. More modest ascent which slows the rate of rise in PA pressure and allows for adaptive remodeling of the microvasculature, drugs which lower PA pressure, and those that can enhance fluid reabsorption will all forestall the deleterious early rise of microvascular pressures and diminished active alveolar fluid reabsorption that precede and underlie the development of HAPE.
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Affiliation(s)
- Erik R Swenson
- Pulmonary, Critical Care and Sleep Medicine, University of Washington, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
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73
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Solaimanzadeh I. Acetazolamide, Nifedipine and Phosphodiesterase Inhibitors: Rationale for Their Utilization as Adjunctive Countermeasures in the Treatment of Coronavirus Disease 2019 (COVID-19). Cureus 2020; 12:e7343. [PMID: 32226695 PMCID: PMC7096066 DOI: 10.7759/cureus.7343] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Effective treatments for Coronavirus Disease 2019 (COVID-19) outbreak are urgently needed. While anti-viral approaches and vaccines are being considered immediate countermeasures are unavailable. The aim of this article is to outline a perspective on the pathophysiology of COVID-19 in the context of the currently available clinical data published in the literature. This article appreciates clinical data published on COVID-19 in the context of another respiratory illness - high altitude pulmonary edema (HAPE). Both conditions have significant similarities that portend pathophysiologic trajectories. Following this potential treatment options emerge. Both COVID-19 and HAPE exhibit a decreased ratio of arterial oxygen partial pressure to fractional inspired oxygen with concomitant hypoxia and tachypnea. There also appears to be a tendency for low carbon dioxide levels in both as well. Radiologic findings of ground glass opacities are present in up to 86% of patients with COVID-19 in addition to patchy infiltrates. Patients with HAPE also exhibit patchy infiltrates throughout the pulmonary fields, often in an asymmetric pattern and CT findings reveal increased lung markings and ground glass-like changes as well. Widespread ground-glass opacities are most commonly a manifestation of hydrostatic pulmonary edema. Similarly, elevated fibrinogen levels in both conditions are likely an epiphenomenon of edema formation rather than coagulation activation. Autopsy results of a COVID-19 fatality revealed bilateral diffuse alveolar damage associated with pulmonary edema, pro-inflammatory concentrates, and indications of early-phase acute respiratory distress syndrome (ARDS). HAPE itself is initially caused by an increase in pulmonary capillary pressure and induces altered alveolar-capillary permeability via high pulmonary artery hydrostatic pressures that lead to a protein-rich and mildly hemorrhagic edema. It appears that COVID-19 and HAPE both discretely converge on ARDS. In light of this, a countermeasure that has been shown to be effective in the analogous condition of HAPE is Acetazolamide. Acetazolamide has a myriad of effects on different organ systems, potently reduces hypoxic pulmonary vasoconstriction, improves minute ventilation and expired vital capacity. Other therapeutics to consider that are also directed towards decreased pulmonary pressure include Nifedipine and Phosphodiesterase inhibitors. This review describes COVID-19 in parallel to HAPE. Deranged respiratory parameters that are present in both conditions are highlighted. The utilization of medications found to be effective in HAPE, for the treatment of COVID-19, is proposed. Given the medical emergency of a growing contagion and the thousands of lives at stake, expedient attempts to improve survival are needed. Acetazolamide, Nifedipine and Phosphodiesterase inhibitors may be potential countermeasures.
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74
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Mulchrone A, Moulton H, Eldridge MW, Chesler NC. Susceptibility to high-altitude pulmonary edema is associated with increased pulmonary arterial stiffness during exercise. J Appl Physiol (1985) 2020; 128:514-522. [PMID: 31854245 DOI: 10.1152/japplphysiol.00153.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
High-altitude pulmonary edema (HAPE), a reversible form of capillary leak, is a common consequence of rapid ascension to high altitude and a major cause of death related to high-altitude exposure. Individuals with a prior history of HAPE are more susceptible to future episodes, but the underlying risk factors remain uncertain. Previous studies have shown that HAPE-susceptible subjects have an exaggerated pulmonary vasoreactivity to acute hypoxia, but incomplete data are available regarding their vascular response to exercise. To examine this, seven HAPE-susceptible subjects and nine control subjects (HAPE-resistant) were studied at rest and during incremental exercise at sea level and at 3,810 m altitude. Studies were conducted in both normoxic (inspired Po2 = 148 Torr) and hypoxic (inspired Po2 = 91 Torr) conditions at each location. Here, we report an expanded analysis of previously published data, including a distensible vessel model that showed that HAPE-susceptible subjects had significantly reduced small distal artery distensibility at sea level compared with HAPE-resistant control subjects [0.011 ± 0.001 vs. 0.021 ± 0.002 mmHg-1; P < 0.001). Moreover, HAPE-susceptible subjects demonstrated constant distensibility over all conditions, suggesting that distal arteries are maximally distended at rest. Consistent with having increased distal artery stiffness, HAPE-susceptible subjects had greater increases in pulmonary artery pulse pressure with exercise, which suggests increased proximal artery stiffness. In summary, HAPE-susceptible subjects have exercise-induced increases in proximal artery stiffness and baseline increases in distal artery stiffness, suggesting increased pulsatile load on the right ventricle.NEW & NOTEWORTHY In comparison to subjects who appear resistant to high-altitude pulmonary edema, those previously symptomatic show greater increases in large and small artery stiffness in response to exercise. These differences in arterial stiffness may be a risk factor for the development of high-altitude pulmonary edema or evidence that consequences of high-altitude pulmonary edema are long-lasting after return to sea level.
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Affiliation(s)
- A Mulchrone
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin
| | - H Moulton
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin
| | - M W Eldridge
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin.,Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin
| | - N C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin.,Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin.,Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
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75
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Zheng Y, Huang J. Angiotensin-converting enzyme gene insertion/deletion polymorphism and high-altitude pulmonary edema: An updated meta-analysis. J Renin Angiotensin Aldosterone Syst 2020; 21:1470320319900039. [PMID: 32106754 PMCID: PMC7052470 DOI: 10.1177/1470320319900039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective: The purpose of the study was to investigate the association between
angiotensin-converting enzyme gene insertion/deletion polymorphism and
high-altitude pulmonary edema. Methods: A systematic search for relevant literature was performed in MEDLINE, CNKI,
and EMBASE. The pooled odds ratios and their corresponding 95% confidence
intervals were calculated in STATA 12.0 software. Results: Seven studies, with a total of 304 patients and 564 controls, qualified for
the inclusion in the analysis. There was no significant association between
angiotensin-converting enzyme insertion/deletion polymorphism and
high-altitude pulmonary edema risk in the total population (DD vs II: odds
ratio=1.07, 95% confidence interval 0.52–2.24; DI vs II: odds ratio=1.12,
0.85–1.49; dominant model: odds ratio=1.07, 0.83–1.40; recessive model: odds
ratio=0.96, 0.53–1.77). Subgroup analysis according to race also revealed no
significant correlation between angiotensin-converting enzyme gene
insertion/deletion polymorphism and high-altitude pulmonary edema. Conclusions: Our findings suggest that angiotensin-converting enzyme insertion/deletion
polymorphism does not contribute to the risk of high-altitude pulmonary
edema. Larger, well-designed studies are required to further validate these
results.
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Affiliation(s)
- Yan Zheng
- Department of Respiratory Medicine, The
Third People’s Hospital of Anji, China
| | - Jin Huang
- Emergency Department, The People’s
Hospital of Anji, China
- Jin Huang, Emergency Department, The
People’s Hospital of Anji, Anji, Zhejiang 313301, China.
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76
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Parr N, Wilkes M, Hawkes LA. Natural Climbers: Insights from Avian Physiology at High Altitude. High Alt Med Biol 2019; 20:427-437. [DOI: 10.1089/ham.2019.0032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Nicole Parr
- College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Cornwall, United Kingdom
| | - Matt Wilkes
- Centre for Altitude Space and Extreme Environment Medicine, Institute of Sport, Exercise and Health, London, United Kingdom
| | - Lucy Alice Hawkes
- Hatherly Laboratories, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
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77
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The Hen or the Egg: Impaired Alveolar Oxygen Diffusion and Acute High-altitude Illness? Int J Mol Sci 2019; 20:ijms20174105. [PMID: 31443549 PMCID: PMC6747186 DOI: 10.3390/ijms20174105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/18/2019] [Accepted: 08/20/2019] [Indexed: 01/11/2023] Open
Abstract
Individuals ascending rapidly to altitudes >2500 m may develop symptoms of acute mountain sickness (AMS) within a few hours of arrival and/or high-altitude pulmonary edema (HAPE), which occurs typically during the first three days after reaching altitudes above 3000-3500 m. Both diseases have distinct pathologies, but both present with a pronounced decrease in oxygen saturation of hemoglobin in arterial blood (SO2). This raises the question of mechanisms impairing the diffusion of oxygen (O2) across the alveolar wall and whether the higher degree of hypoxemia is in causal relationship with developing the respective symptoms. In an attempt to answer these questions this article will review factors affecting alveolar gas diffusion, such as alveolar ventilation, the alveolar-to-arterial O2-gradient, and balance between filtration of fluid into the alveolar space and its clearance, and relate them to the respective disease. The resultant analysis reveals that in both AMS and HAPE the main pathophysiologic mechanisms are activated before aggravated decrease in SO2 occurs, indicating that impaired alveolar epithelial function and the resultant diffusion limitation for oxygen may rather be a consequence, not the primary cause, of these altitude-related illnesses.
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78
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Forton K, Motoji Y, Pezzuto B, Caravita S, Delbaere A, Naeije R, Faoro V. Decreased pulmonary vascular distensibility in adolescents conceived by in vitro fertilization. Hum Reprod 2019; 34:1799-1808. [DOI: 10.1093/humrep/dez113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 04/23/2019] [Indexed: 12/16/2022] Open
Abstract
Abstract
STUDY QUESTION
What is the functional relevance of decreased pulmonary vascular distensibility in adolescents conceived by IVF?
SUMMARY ANSWER
Children born by IVF have a slight decrease in pulmonary vascular distensibility observed during normoxic exercise that is not associated with altered right ventricular function and aerobic exercise capacity.
WHAT IS KNOWN ALREADY
General vascular dysfunction and increased hypoxic pulmonary hypertension have been reported in ART children as compared to controls. Pulmonary hypertension or decreased pulmonary vascular distensibility may affect right ventricular function and thereby possibly limit maximal cardiac output and aerobic exercise capacity.
STUDY DESIGN, SIZE, DURATION
This prospective case-control study enrolled 15 apparently healthy adolescents conceived by IVF/ICSI after fresh embryo transfer paired in a 2 to 1 ratio to 30 naturally conceived adolescents between March 2015 and May 2018.
PARTICIPANTS/MATERIALS, SETTING, METHODS
Fifteen IVF/ICSI adolescents and 30 controls from singleton gestations matched by age, gender, weight, height and physical activity underwent exercise echocardiography, lung diffusion capacity measurements and a cycloergometer cardiopulmonary exercise test. A pulmonary vascular distensibility coefficient α was determined from the pulmonary arterial pressure (PAP) versus cardiac output (Q) relationships. Pulmonary capillary volume (Vc) was calculated from single breath nitric oxide and carbon monoxide lung diffusion capacity measurements (DLCO and DLNO) at rest and during exercise (100 W). Eight of the IVF subjects and eight controls underwent a 30 min hypoxic challenge at rest with a fraction of inspired oxygen of 0.12 to assess hypoxic pulmonary vasoconstriction.
MAIN RESULTS AND THE ROLE OF CHANCE
In normoxia, oxygen uptake (VO2), blood pressure, DLCO, DLNO, echocardiographic indices of right ventricular function, Q and PAP at rest and during exercise were similar in both groups. However, IVF children had a lower pulmonary vascular distensibility coefficient α (1.2 ± 0.3 versus 1.5 ± 0.3%/mmHg, P = 0.02) and a blunted exercise-induced increase in Vc (24 versus 32%, P < 0.05). Hypoxic-induced increase in pulmonary vascular resistance in eight IVF subjects versus eight controls was similar.
LIMITATIONS, REASONS FOR CAUTION
The IVF cohort was small, and thus type I or II errors could have occurred in spite of careful matching of each case with two controls. ART evolved over the years, so that it is not certain that the presently reported subtle changes will be reproducible in the future. As the study was limited to singletons born after fresh embryo transfers, our observations cannot be extrapolated to singletons born after frozen embryo transfer.
WIDER IMPLICATIONS OF THE FINDINGS
The present study suggests that adolescents conceived by IVF have preserved right ventricular function and aerobic exercise capacity despite a slight alteration in pulmonary vascular distensibility as assessed by two entirely different methods, i.e. exercise echocardiography and lung diffusing capacity measurements. However, the long-term prognostic relevance of this slight decrease in pulmonary vascular distensibility needs to be evaluated in prospective large scale and long-term outcome studies.
STUDY FUNDING/COMPETING INTEREST(S)
Dr Caravita was supported by an ERS PAH short term research training fellowship (STRTF2014-5264). Dr Pezzuto was funded by an Italian Society of cardiology grant. Dr Motoji was supported by a grant from the Cardiac Surgery Funds, Belgium. All authors have no conflicts of interests to declare.
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Affiliation(s)
- K Forton
- Cardiopulmonary Exercise Laboratory, Faculty of Motor Science, Université Libre de Bruxelles, Brussels, Belgium
- Department of Cardiology, Erasmus University Hospital, Brussels, Belgium
| | - Y Motoji
- Cardiopulmonary Exercise Laboratory, Faculty of Motor Science, Université Libre de Bruxelles, Brussels, Belgium
- Department of Cardiology, Erasmus University Hospital, Brussels, Belgium
| | - B Pezzuto
- Cardiopulmonary Exercise Laboratory, Faculty of Motor Science, Université Libre de Bruxelles, Brussels, Belgium
| | - S Caravita
- Department of Cardiology, Erasmus University Hospital, Brussels, Belgium
- Department of Cardiovascular, Neural and Metabolic Sciences, Ospedale San Luca, Istituto Auxologico Italiano IRCCS, Milano, Italy
| | - A Delbaere
- Fertility Clinic, Erasmus University Hospital, Brussels, Belgium
| | - R Naeije
- Cardiopulmonary Exercise Laboratory, Faculty of Motor Science, Université Libre de Bruxelles, Brussels, Belgium
- Laboratory of Physiopathology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - V Faoro
- Cardiopulmonary Exercise Laboratory, Faculty of Motor Science, Université Libre de Bruxelles, Brussels, Belgium
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79
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Bölter C, Gabriel P, Appelt P, Salameh A, Schierle K, Rassler B. Effects of Adrenergic Agonists and Antagonists on Cardiopulmonary Function During Normobaric Hypoxia in Rat. Front Physiol 2019; 10:860. [PMID: 31333500 PMCID: PMC6624647 DOI: 10.3389/fphys.2019.00860] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/20/2019] [Indexed: 11/23/2022] Open
Abstract
Pulmonary edema (PE) is an issue widely noted in acute exposure to hypoxia as seen in high altitude climbers, yet the etiology of this is not defined. Previous studies in rats showed that both hypoxia and strong sympathetic activation may induce PE. As acute exposure to hypoxia is accompanied by sympathetic activation, we assume that this may impair pulmonary circulation and contribute to the development of hypoxic PE. The aim of the present study was to investigate the effects of adrenergic agonists and antagonists as models for overstimulation and suppression, respectively, of sympathetic activity on cardiovascular function and formation of PE in hypoxic rats. Norepinephrine or adrenergic blockers were infused to rats exposed to normobaric hypoxia with 10% O2 over time intervals up to 24 h. Normoxic and hypoxic controls received 0.9% NaCl infusion. We evaluated hemodynamic function and lung histology. A significant decrease of left ventricular systolic function was observed after 6 h of hypoxia. This effect was less pronounced with α-adrenergic blockade but was more severe with combined α-plus β-adrenergic blockade. Norepinephrine delayed the onset of hypoxic left ventricular depression but did not reduce its degree. Significant PE developed after 16 h of hypoxia. It regressed under α- but not with β-adrenergic blockade, and was aggravated by combining hypoxia with norepinephrine. Almost half of the animals exposed to hypoxia over 16–24 h suffered cardiorespiratory arrest during the experiment and presented with signs of acute right ventricular failure. They had significantly elevated serum catecholamine concentrations and significantly stronger PE than the others. Notably, most of them had received norepinephrine or combined adrenergic blockade. Mild changes in serum catecholamine concentrations indicated that hypoxic sympathoadrenergic activation was only weak. Hence, it was not sufficient to prevent left ventricular depression. However, the results show that α-adrenergic mechanisms contribute to the formation of hypoxic PE. Adrenergic blockade but also sympathetic overactivity may induce pulmonary congestion, PE and acute right ventricular failure indicating that a fine balance of sympathetic activation under hypoxic conditions is crucial. This has important implications for climbers to high altitude as well as for patients suffering from hypoxia.
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Affiliation(s)
- Christian Bölter
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Philipp Gabriel
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Peter Appelt
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Aida Salameh
- Department of Pediatric Cardiology, Heart Centre, University of Leipzig, Leipzig, Germany
| | - Katrin Schierle
- Institute of Pathology, University of Leipzig, Leipzig, Germany
| | - Beate Rassler
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
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80
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Naeije R. Pulmonary hypertension at high altitude. Eur Respir J 2019; 53:53/6/1900985. [DOI: 10.1183/13993003.00985-2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 11/05/2022]
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81
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Young JM, Williams DR, Thompson AAR. Thin Air, Thick Vessels: Historical and Current Perspectives on Hypoxic Pulmonary Hypertension. Front Med (Lausanne) 2019; 6:93. [PMID: 31119132 PMCID: PMC6504829 DOI: 10.3389/fmed.2019.00093] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/16/2019] [Indexed: 12/21/2022] Open
Abstract
The association between pulmonary hypertension (PH) and hypoxia is well-established, with two key mechanistic processes, hypoxic pulmonary vasoconstriction and hypoxia-induced vascular remodeling, driving changes in pulmonary arterial pressure. In contrast to other forms of pulmonary hypertension, the vascular changes induced by hypoxia are reversible, both in humans returning to sea-level from high altitude and in animal models. This raises the intriguing possibility that the molecular drivers of these hypoxic processes could be targeted to modify pulmonary vascular remodeling in other contexts. In this review, we outline the history of research into PH and hypoxia, before discussing recent advances in our understanding of this relationship at the molecular level, focussing on the role of the oxygen-sensing transcription factors, hypoxia inducible factors (HIFs). Emerging links between HIF and vascular remodeling highlight the potential utility in inhibiting this pathway in pulmonary hypertension and raise possible risks of activating this pathway using HIF-stabilizing medications.
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Affiliation(s)
- Jason M. Young
- Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
- Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
| | | | - A. A. Roger Thompson
- Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
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82
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Hilty MP, Merz TM, Hefti U, Ince C, Maggiorini M, Pichler Hefti J. Recruitment of non-perfused sublingual capillaries increases microcirculatory oxygen extraction capacity throughout ascent to 7126 m. J Physiol 2019; 597:2623-2638. [PMID: 30843200 DOI: 10.1113/jp277590] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/05/2019] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS A physiological response to increase microcirculatory oxygen extraction capacity at high altitude is to recruit capillaries. In the present study, we report that high altitude-induced sublingual capillary recruitment is an intrinsic mechanism of the sublingual microcirculation that is independent of changes in cardiac output, arterial blood pressure or systemic vascular hindrance. Using a topical nitroglycerin challenge to the sublingual microcirculation, we show that high altitude-related capillary recruitment is a functional response of the sublingual microcirculation as opposed to an anatomical response associated with angiogenesis. The concurrent presence of a low capillary density and high microvascular reactivity to topical nitroglycerin at sea level was found to be associated with a failure to reach the summit, whereas the presence of a high baseline capillary density with the ability to further increase maximum recruitable capillary density upon ascent to an extreme altitude was associated with summit success. ABSTRACT A high altitude (HA) stay is associated with an increase in sublingual capillary total vessel density (TVD), suggesting microvascular recruitment. We hypothesized that microvascular recruitment occurs independent of cardiac output changes, that it relies on haemodynamic changes within the microcirculation as opposed to structural changes and that microcirculatory function is related to individual performance at HA. In 41 healthy subjects, sublingual handheld vital microscopy and echocardiography were performed at sea level (SL), as well as at 6022 m (C2) and 7042 m (C3), during ascent to 7126 m within 21 days. Sublingual topical nitroglycerin was applied to measure microvascular reactivity and maximum recruitable TVD (TVDNG ). HA exposure decreased resting cardiac output, whereas TVD (mean ± SD) increased from 18.81 ± 3.92 to 20.92 ± 3.66 and 21.25 ± 2.27 mm mm-2 (P < 0.01). The difference between TVD and TVDNG was 2.28 ± 4.59 mm mm-2 at SL (P < 0.01) but remained undetectable at HA. Maximal TVDNG was observed at C3. Those who reached the summit (n = 15) demonstrated higher TVD at SL (P < 0.01), comparable to TVDNG in non-summiters (n = 21) at SL and in both groups at C2. Recruitment of sublingual capillary TVD to increase microcirculatory oxygen extraction capacity at HA was found to be an intrinsic mechanism of the microcirculation independent of cardiac output changes. Microvascular reactivity to topical nitroglycerin demonstrated that HA-related capillary recruitment is a functional response as opposed to a structural change. The performance of the vascular microcirculation needed to reach the summit was found to be associated with a higher TVD at SL and the ability to further increase TVDNG upon ascent to extreme altitude.
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Affiliation(s)
- Matthias Peter Hilty
- Intensive Care Unit, University Hospital of Zurich, Zurich, Switzerland.,Department of Intensive Care, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Tobias Michael Merz
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Cardiovascular Intensive Care Unit, Auckland City Hospital, Auckland, New Zealand
| | - Urs Hefti
- Swiss Sportclinic, Bern, Switzerland
| | - Can Ince
- Department of Intensive Care, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Marco Maggiorini
- Intensive Care Unit, University Hospital of Zurich, Zurich, Switzerland
| | - Jacqueline Pichler Hefti
- Department of Pulmonary Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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83
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Hackett PH, Yarnell PR, Weiland DA, Reynard KB. Acute and Evolving MRI of High-Altitude Cerebral Edema: Microbleeds, Edema, and Pathophysiology. AJNR Am J Neuroradiol 2019; 40:464-469. [PMID: 30679208 DOI: 10.3174/ajnr.a5897] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 10/12/2018] [Indexed: 11/07/2022]
Abstract
MR imaging of high-altitude cerebral edema shows reversible WM edema, especially in the corpus callosum and subcortical WM. Recent studies have revealed hemosiderin deposition in WM long after high-altitude cerebral edema has resolved, providing a high-altitude cerebral edema "footprint." We wished to determine whether these microbleeds are present acutely and also describe the evolution of all MR imaging findings. In 8 patients with severe high-altitude cerebral edema, we obtained 26 studies: 18 with 3T and 8 with 1.5T scanners, during the acute stage, recovery, and follow-up in 7 patients and acutely in 1 patient. Imaging confirmed reversible cytotoxic and vasogenic WM edema that unexpectedly worsened the first week during clinical improvement before resolving. The 3T SWI, but not 1.5T imaging, showed extensive microbleeds extending beyond areas of edema seen acutely, which persisted and with time coalesced. These findings support cytotoxic and vasogenic edema leading to capillary failure/leakage in the pathophysiology of high-altitude cerebral edema and provide imaging correlation to the clinical course.
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Affiliation(s)
- P H Hackett
- From the Altitude Research Center (P.H.H.), Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Center, Aurora, Colorado
| | | | - D A Weiland
- Colorado Imaging Associates (D.A.W., K.B.R.), St. Anthony Hospital, Lakewood, Colorado
| | - K B Reynard
- Colorado Imaging Associates (D.A.W., K.B.R.), St. Anthony Hospital, Lakewood, Colorado
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84
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Jin T, Zhu L, Bai M, He X, Wang L, Yuan D, Li S, He Y. Association between the IL1R2 rs2072472 polymorphism and high-altitude pulmonary edema risk. Mol Genet Genomic Med 2019; 7:e542. [PMID: 30672138 PMCID: PMC6418374 DOI: 10.1002/mgg3.542] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/11/2018] [Accepted: 12/02/2018] [Indexed: 01/06/2023] Open
Abstract
Aim High‐altitude pulmonary edema (HAPE), as a multifactorial disease, is caused by stress failure and involves both environmental and genetic factors. Study shows that IL‐1 receptors can selectively decrease the oxygen arterial hypertension and influence the blood coagulation. So we evaluated whether genetic polymorphisms in IL1R1 and 1L1R2 genes are associated with the risk of HAPE in Chinese Han population. Methods Ten susceptible SNPs in the IL1R1 and IL1R2 genes were genotyped among 265 HAPE cases and 303 controls using the Agena MassARRAY platform. The associations of the SNP frequencies with HAPE were analyzed by chi‐square (χ2) test/Fisher's test. The genetic models were used to evaluate associations. Results In the allele model, we found that rs2072472 was significantly associated with a 0.73‐fold decreased risk of HAPE (OR = 0.73, 95% CI = 0.55–0.97, p = 0.033). In the genetic model analysis, the rs2072472 in IL1R2 gene was associated with a 0.32‐fold decreased risk of HAPE in the codominant model, 0.67‐fold decreased risk of HAPE in the dominant model, 0.36‐fold decreasing the risk of HAPE in the recessive model, and 0.66‐fold decreased risk of HAPE in the log‐additive model, respectively. We found three candidate SNPs (rs11674595, rs4851527, and rs719250) in the IL1R2 gene have shown strong linkage, and none of the haplotypes was significantly associated with risk of HAPE. Conclusion These findings suggested that IL1R2 polymorphisms may contribute to the protection of HAPE.
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Affiliation(s)
- Tianbo Jin
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China.,Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Sciences, Northwest University, Xi'an, Shaanxi, China
| | - Linhao Zhu
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China
| | - Mei Bai
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China
| | - Xue He
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China
| | - Li Wang
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China
| | - Dongya Yuan
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China
| | - Shanqu Li
- Medical Examination Center of Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yongjun He
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, Xianyan, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China
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85
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Kim CH, Sajgalik P, Van Iterson EH, Jae SY, Johnson BD. The effect of remote ischemic pre-conditioning on pulmonary vascular pressure and gas exchange in healthy humans during hypoxia. Respir Physiol Neurobiol 2019; 261:62-66. [PMID: 30658096 DOI: 10.1016/j.resp.2019.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/26/2018] [Accepted: 01/15/2019] [Indexed: 11/29/2022]
Abstract
This study investigated whether rIPC alters the typical changes in pulmonary arterial pressure, pulmonary gas exchange associated with exercise in hypoxia. METHODS 16 healthy adults were randomized to either rIPC treatment (n = 8) or control (n = 8). Afterward, subjects performed supine ergometry at constant load (30 W, 40˜50 rpm) for 25 min during hypoxia (12.5% O2). Following a 90˜120 min rest, either rIPC or sham treatment was performed, which was then followed by post-assessment exercise. Throughout exercise, pulmonary arterial systolic pressure (PASP) and mean pulmonary arterial pressure (mPAP) were measured via echocardiography, while pulmonary gas exchange was being assessed. RESULTS The rICP group demonstrated improved PASP and mPAP (p < 0.05), whereas the control group did not. Additionally, breathing efficiency (VE/VCO2) and end-tidal CO2 (PETCO2) were improved in rIPC group (p < 0.05), but not in controls. CONCLUSION These data suggest that rIPC contributes to reduced pulmonary arterial pressure, and improved pulmonary gas exchange during hypoxic exercise. However, follow-up studies are needed to apply these findings to patient care settings.
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Affiliation(s)
- Chul-Ho Kim
- Human Integrative Environmental Physiology Laboratory, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States.
| | - Pavol Sajgalik
- Human Integrative Environmental Physiology Laboratory, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Erik H Van Iterson
- Human Integrative Environmental Physiology Laboratory, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Sae Young Jae
- Department of Sports Science, University of Seoul, Seoul, Republic of Korea
| | - Bruce D Johnson
- Human Integrative Environmental Physiology Laboratory, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
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86
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Li Y, Zhang Y, Zhang Y. Research advances in pathogenesis and prophylactic measures of acute high altitude illness. Respir Med 2018; 145:145-152. [DOI: 10.1016/j.rmed.2018.11.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 09/14/2018] [Accepted: 11/06/2018] [Indexed: 12/30/2022]
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87
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Berger MM, Grocott MPW. Facing acute hypoxia: from the mountains to critical care medicine. Br J Anaesth 2018; 118:283-286. [PMID: 28203722 DOI: 10.1093/bja/aew407] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- M M Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Salzburg, Austria.,Department of Anesthesiology, University Hospital Heidelberg, Germany
| | - M P W Grocott
- Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.,Critical Care Research Area, NIHR Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.,Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,UCL Centre for Altitude, Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, First Floor, 170 Tottenham Court Road, London W1T 7HA, UK
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88
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Sareban M, Perz T, Macholz F, Reich B, Schmidt P, Fried S, Mairbäurl H, Berger MM, Niebauer J. Impairment of left atrial mechanics does not contribute to the reduction in stroke volume after active ascent to 4559 m. Scand J Med Sci Sports 2018; 29:223-231. [PMID: 30372563 PMCID: PMC7379646 DOI: 10.1111/sms.13325] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/08/2018] [Accepted: 10/17/2018] [Indexed: 01/07/2023]
Abstract
Hypoxia challenges left ventricular (LV) function due to reduced energy supply. Conflicting results exist whether high‐altitude exposure impairs LV diastolic function and thus contributes to the high altitude‐induced increase in systolic pulmonary artery pressure (sPAP) and reduction in stroke volume (SV). This study aimed to assess LV diastolic function, LV end‐diastolic pressure (LVEDP), and LA mechanics using comprehensive echocardiographic imaging in healthy volunteers at 4559 m. Fifty subjects performed rapid (<20 hours) and active ascent from 1130 m to 4559 m (high). All participants underwent echocardiography during baseline examination at 424 m (low) as well as 7, 20 and 44 hours after arrival at high altitude. Heart rate (HR), sPAP, and comprehensive volumetric‐ and Doppler‐ as well as speckle tracking‐derived LA strain parameters were obtained to assess LV diastolic function, LA mechanics, and LVEDP in a multiparametric approach. Data for final analyses were available in 46 subjects. HR (low: 64 ± 11 vs high: 79 ± 14 beats/min, P < 0.001) and sPAP (low: 24.4 ± 3.8 vs high: 38.5 ± 8.2 mm Hg, P < 0.001) increased following ascent and remained elevated at high altitude. Stroke volume (low: 64.5 ± 15.0 vs high: 58.1 ± 16.4 mL, P < 0.001) and EDV decreased following ascent and remained decreased at high altitude due to decreased LV passive filling volume, whereas LA mechanics were preserved. There was no case of LV diastolic dysfunction or increased LVEDP estimates. In summary, this study shows that rapid and active ascent of healthy individuals to 4559 m impairs passive filling and SV of the LV. These alterations were not related to changes in LV and LA mechanics.
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Affiliation(s)
- Mahdi Sareban
- University Institute of Sports Medicine, Prevention and Rehabilitation and Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Tabea Perz
- University Institute of Sports Medicine, Prevention and Rehabilitation and Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Franziska Macholz
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Bernhard Reich
- University Institute of Sports Medicine, Prevention and Rehabilitation and Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Peter Schmidt
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Sebastian Fried
- Medical Clinic VII, Sports Medicine, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany
| | - Heimo Mairbäurl
- Medical Clinic VII, Sports Medicine, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany
| | - Marc M Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Josef Niebauer
- University Institute of Sports Medicine, Prevention and Rehabilitation and Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
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89
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Pratali L. Right Heart-Pulmonary Circulation at High Altitude and the Development of Subclinical Pulmonary Interstitial Edema. Heart Fail Clin 2018; 14:333-337. [PMID: 29966631 DOI: 10.1016/j.hfc.2018.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most healthy subjects can develop a subclinical interstitial pulmonary edema that is a complex and multifactor phenomenon, still with unanswered questions, and might be one line of defense against the development of severe symptomatic lung edema. Whether the acute, reversible increase in lung fluid content is really an innocent and benign part of the adaptation to extreme physiologic condition or rather the clinically relevant marker of an individual vulnerability to life-threatening high altitude pulmonary edema remains to be established in future studies. Thus the question if encouraging more conservative habits to climb is right or not remains open.
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Affiliation(s)
- Lorenza Pratali
- Department of Institute of Clinical Physiology, National research Council, Via Moruzzi 1, Pisa 56214, Italy.
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90
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Pezzuto B, Forton K, Badagliacca R, Motoji Y, Faoro V, Naeije R. Right ventricular dyssynchrony during hypoxic breathing but not during exercise in healthy subjects: a speckle tracking echocardiography study. Exp Physiol 2018; 103:1338-1346. [PMID: 30055062 DOI: 10.1113/ep087027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 07/27/2018] [Indexed: 12/31/2022]
Abstract
NEW FINDINGS What is the central question of this study? Right ventricular dyssynchrony in severe pulmonary hypertension is associated with a poor prognosis. However, it has recently been observed in patients with lung or connective tissue disease and pulmonary artery pressure at the upper limits of normal. The mechanisms of right ventricular dyssynchrony in pulmonary hypertension remain uncertain. What is the main finding and its importance? Acute hypoxic breathing, but not normoxic exercise, induces an increase in right ventricular dyssynchrony detected by speckle tracking echocardiography in healthy subjects. These results add new insights into the determinants of right ventricular dyssynchrony, suggesting a role for systemic factors added to afterload in the pathophysiology of right ventricular inhomogeneity of contraction. ABSTRACT Pulmonary hypertension (PH) has been shown to be associated with regional inhomogeneity (or dyssynchrony) of right ventricular (RV) contraction. Right ventricular dyssynchrony is an independent predictor of decreased survival in advanced PH, but has also been reported in patients with only mildly elevated pulmonary artery pressure (PAP). The mechanisms of RV dyssynchrony in PH remain uncertain. Our aim was to evaluate RV regional function in healthy subjects during acute hypoxia and during exercise. Seventeen healthy subjects (24 ± 6 years) underwent a speckle tracking echocardiography of the RV at rest in normoxia and every 15 min during a 60 min exposure to hypoxic breathing ( F I O 2 12%). Ten of the subjects also underwent an incremental cycle ergometry in normoxia to 100 W, with the same echocardiographic measurements. Dyssynchrony was measured as the SD of the times to peak systolic strain of the four basal and mid RV segments corrected for the heart rate (RV-SD4). RV-SD4 increased during hypoxia from 12 ± 7 to 22 ± 11 ms in spite of mild increases in mean PAP (mPAP) from 15 ± 2 to 20 ± 2 mmHg and pulmonary vascular resistance (PVR) from 1.18 ± 0.15 to 1.4 ± 0.15 Wood units (WU). During exercise RV-SD4 did not significantly change (from 12 ± 6 ms to 14 ± 6 ms), while mPAP increased to 25 ± 2 mmHg and PVR was unchanged. These data show that in healthy subjects, RV contraction is inhomogeneous in hypoxia but not during exercise. Since PAP increases more during exercise, RV dyssynchrony in hypoxia may be explained by a combination of mechanical (RV afterload) and systemic (hypoxia) factors.
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Affiliation(s)
- Beatrice Pezzuto
- Department of Exercise Physiology; Faculty of Motor Sciences, Université Libre de Bruxelles; Route de Lennik 808 Bruxelles Belgium
- Department of Cardiovascular and Respiratory Sciences, Sapienza University of Rome; Rome Italy
| | - Kevin Forton
- Department of Exercise Physiology; Faculty of Motor Sciences, Université Libre de Bruxelles; Route de Lennik 808 Bruxelles Belgium
| | - Roberto Badagliacca
- Department of Cardiovascular and Respiratory Sciences, Sapienza University of Rome; Rome Italy
| | - Yoshiki Motoji
- Department of Exercise Physiology; Faculty of Motor Sciences, Université Libre de Bruxelles; Route de Lennik 808 Bruxelles Belgium
| | - Vitalie Faoro
- Department of Exercise Physiology; Faculty of Motor Sciences, Université Libre de Bruxelles; Route de Lennik 808 Bruxelles Belgium
| | - Robert Naeije
- Department of Exercise Physiology; Faculty of Motor Sciences, Université Libre de Bruxelles; Route de Lennik 808 Bruxelles Belgium
- Department of Cardiology, Erasme University Hospital of Brussels; Route de Lennik 808 Bruxelles Belgium
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91
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He X, Wang L, Zhu L, Yuan D, He Y, Jin T. A case-control study of the genetic polymorphism of IL6 and HAPE risk in a Chinese Han population. CLINICAL RESPIRATORY JOURNAL 2018; 12:2419-2425. [PMID: 30074683 DOI: 10.1111/crj.12922] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/15/2018] [Accepted: 05/24/2018] [Indexed: 11/28/2022]
Abstract
AIMS The role of inflammatory cytokines in High-altitude pulmonary edema (HAPE) remains unclear. The purpose of this study was to evaluate the role of IL4 and IL6 gene polymorphism in the development of HAPE in Chinese people. METHODS In the present study, we screened ten polymorphisms of IL4 and IL6 gene in 265 HAPE and 303 healthy volunteers. Genotypes were determined using the Sequenom MassARRAY method. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression. RESULTS Two single-nucleotide polymorphisms (SNPs) in the IL6 gene were significantly associated with HAPE. Rs1800796 and rs1524107 (G vs C, OR = 1.31, 95%CI = 1.01-1.69, P = .041 and T vs C, OR = 1.35, 95%CI = 1.05-1.74, P = .020, respectively). However, there did not found any association for IL4 gene. CONCLUSION Inflammatory cytokines may play a role in the progress of HAPE. These polymorphisms could be genetic markers for predicting the susceptibility to HAPE.
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Affiliation(s)
- Xue He
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China
| | - Li Wang
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China
| | - Linhao Zhu
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China
| | - Dongya Yuan
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China
| | - Yongjun He
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China
| | - Tianbo Jin
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi, China.,Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China.,Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, XizangMinzu University, Xianyang, Shaanxi, China.,Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an, Shaanxi, China
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92
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Abstract
BACKGROUND Acute mountain sickness (AMS) is common in high-altitude travelers, and may lead to life-threatening high-altitude cerebral edema (HACE) or high-altitude pulmonary edema (HAPE). The inhaled drugs have a much lower peak serum concentrations and a shorter half-life period than oral drugs, which give them a special character, greater local effects in the lung. Meanwhile, short-term administration of inhaled drugs results in almost no adverse reactions. METHODS We chose inhaled ipratropium bromide/salbutamol sulfate (combivent, COM), budesonide (pulmicortrespules, BUD), and salbutamol sulfate (ventolin, VEN) in our study to investigate their prophylactic efficacy against AMS. Since COM is a compound drug of ipratropium bromide and salbutamol sulfate, to verify which part of COM plays a role in the prevention of AMS, we also tested VEN in our experiment. RESULTS In our study, Lake Louise scores (LLS) in the COM (1.14 ± 0.89 vs 1.91 ± 1.23, P < .05) and BUD (1.35 ± 0.94 vs 1.91 ± 1.23, P < .05) groups were both significantly lower than the placebo group at 72 hours. There were no significant differences in LLS scores among the 4 groups at 120 hours. The incidence of AMS in the COM group was significantly reduced at 72 hours (16.7% in COM group vs 43.4% in placebo group, P < .05) after exposure to high-altitude. There were no significant differences in AMS incidences at 120 hours among the 4 groups. CONCLUSION The prophylactic use of COM could prevent AMS in young Chinese male at 72 hours after high-altitude exposure. BUD also could reduce LLS but not prevent AMS at 72 hours. Ipratropium bromide maybe the effective drug in COM work on the prevention of AMS alone.
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Affiliation(s)
- Xiaomei Wang
- Department of Transfusion Medicine
- Department of Geriatrics
| | | | - Rong Li
- Department of Laboratory Medicine, Southwest Hospital, The Third Military Medical University (Army Medical University), Chongqing, China
| | - Weiling Fu
- Department of Laboratory Medicine, Southwest Hospital, The Third Military Medical University (Army Medical University), Chongqing, China
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93
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Response to: Comment on "Soluble Urokinase-Type Plasminogen Activator Receptor Plasma Concentration May Predict Susceptibility to High Altitude Pulmonary Edema". Mediators Inflamm 2018; 2018:8036759. [PMID: 29853793 PMCID: PMC5954876 DOI: 10.1155/2018/8036759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/28/2018] [Indexed: 11/18/2022] Open
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94
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Abstract
INTRODUCTION Altitude is associated with a decrease in partial pressure of oxygen. Hypoxia induces pulmonary vasoconstriction with subsequent fixed increase in pulmonary artery pressure, and eventual right heart failure. CURRENT KNOWLEDGE High altitude exposure is associated with an increase in pulmonary artery pressure that is proportional to initial vasoconstriction. Echocardiographic evaluations on a large number of subjects show that the altitude-induced increase in pulmonary pressure is generally modest and does not exceed the 25mmHg that are diagnostic of pulmonary hypertension. This does not greatly increase right ventricular afterload, so that imaging of the right ventricle only shows some alterations of indices of systolic or diastolic function, but preserved contractile reserve during exercise. In less than 1% of cases, hypoxic vasoconstriction is strong and may be a cause of severe pulmonary hypertension and right heart failure. PERSPECTIVES The prognostic relevance of altitude-induced pulmonary hypertension and associated cardiac function alterations is not known. Treatment of hypoxic pulmonary hypertension relies on evacuation to a lower altitude, oxygen and pulmonary vasodilators. These treatment strategies have not been rigorously evaluated. CONCLUSIONS Altitude may be a cause of right heart failure. This uncommon complication of altitude exposure requires further epidemiological and therapeutic studies.
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95
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Gerges C, Gerges M, Fesler P, Pistritto AM, Konowitz NP, Jakowitsch J, Celermajer DS, Lang I. In-depth haemodynamic phenotyping of pulmonary hypertension due to left heart disease. Eur Respir J 2018; 51:13993003.00067-2018. [DOI: 10.1183/13993003.00067-2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/10/2018] [Indexed: 12/22/2022]
Abstract
The commonest cause of pulmonary hypertension (PH) is left heart disease (LHD). The current classification system for definitions of PH-LHD is under review. We therefore performed prospective in-depth invasive haemodynamic phenotyping in order to assess the site of increased pulmonary vascular resistance (PVR) in PH-LHD subsets.Based on pulmonary artery occlusion waveforms yielding an estimate of the effective capillary pressure, we partitioned PVR in larger arterial (Rup, upstream resistance) and small arterial plus venous components (Rds, downstream resistance). In the case of small vessel disease, Rup decreases and Rds increases. Inhaled nitric oxide (NO) testing was used to assess acute vasoreactivity.Right ventricular afterload (PVR, pulmonary arterial compliance and effective arterial elastance) was significantly higher in combined post- and pre-capillary PH (Cpc-PH, n=35) than in isolated post-capillary PH (Ipc-PH, n=20). Right ventricular afterload decreased during inhalation of NO in Cpc-PH and idiopathic pulmonary arterial hypertension (n=31), but remained unchanged in Ipc-PH. Rup was similar in Cpc-PH (66.8±10.8%) and idiopathic pulmonary arterial hypertension (65.0±12.2%; p=0.530) suggesting small vessel disease, but significantly higher in Ipc-PH (96.5±4.5%; p<0.001) suggesting upstream transmission of elevated left atrial pressure.Right ventricular afterload is driven by elevated left atrial pressure in Ipc-PH and is further increased by elevated small vessel resistance in Cpc-PH. Cpc-PH is responsive to inhaled NO. Our data support current definitions of PH-LHD subsets.
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96
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Huertas A, Guignabert C, Barberà JA, Bärtsch P, Bhattacharya J, Bhattacharya S, Bonsignore MR, Dewachter L, Dinh-Xuan AT, Dorfmüller P, Gladwin MT, Humbert M, Kotsimbos T, Vassilakopoulos T, Sanchez O, Savale L, Testa U, Wilkins MR. Pulmonary vascular endothelium: the orchestra conductor in respiratory diseases. Eur Respir J 2018; 51:13993003.00745-2017. [DOI: 10.1183/13993003.00745-2017] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 02/03/2018] [Indexed: 12/15/2022]
Abstract
The European Respiratory Society (ERS) Research Seminar entitled “Pulmonary vascular endothelium: orchestra conductor in respiratory diseases - highlights from basic research to therapy” brought together international experts in dysfunctional pulmonary endothelium, from basic science to translational medicine, to discuss several important aspects in acute and chronic lung diseases. This review will briefly sum up the different topics of discussion from this meeting which was held in Paris, France on October 27–28, 2016. It is important to consider that this paper does not address all aspects of endothelial dysfunction but focuses on specific themes such as: 1) the complex role of the pulmonary endothelium in orchestrating the host response in both health and disease (acute lung injury, chronic obstructive pulmonary disease, high-altitude pulmonary oedema and pulmonary hypertension); and 2) the potential value of dysfunctional pulmonary endothelium as a target for innovative therapies.
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97
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Altered Left Ventricular Geometry and Torsional Mechanics in High Altitude-Induced Pulmonary Hypertension: A Three-Dimensional Echocardiographic Study. J Am Soc Echocardiogr 2018; 31:314-322. [DOI: 10.1016/j.echo.2017.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Indexed: 11/21/2022]
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98
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Liptzin DR, Abman SH, Giesenhagen A, Ivy DD. An Approach to Children with Pulmonary Edema at High Altitude. High Alt Med Biol 2018; 19:91-98. [PMID: 29470103 DOI: 10.1089/ham.2017.0096] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Liptzin, Deborah R., Steven H. Abman, Ann Giesenhagen, and D. Dunbar Ivy. An approach to children with pulmonary edema at high altitude. High Alt Med Biol. 19:91-98, 2018. INTRODUCTION Diagnosis of high-altitude illness can be more challenging in children, especially those who are preverbal. Families often travel to high elevations for family vacations, either for skiing, hiking, and/or camping. They may present to their primary care providers looking for anticipatory guidance before travel or may follow-up after developing high-altitude illness. High-altitude pulmonary edema (HAPE) can be fatal. OBSERVATIONS There is no indication for HAPE prophylaxis in altitude naive children. Children may develop HAPE either when traveling from low altitude to high altitude for vacation (classic HAPE), when returning to high-altitude homes after travel to low altitude (reentry HAPE), or even with a respiratory illness at high altitude without any change in elevation (high-altitude resident pulmonary edema or HARPE). Children may be more susceptible to HAPE because of increased vascular reactivity, immature control of breathing, and increased frequency of respiratory illnesses. Children with HAPE warrant evaluation for underlying cardiopulmonary abnormalities, including structural heart disease and pulmonary hypertension. Treatment of HAPE includes supplemental oxygen and descent, but underlying cardiopulmonary disease may also help guide treatment and prevention. CONCLUSIONS AND RELEVANCE Evaluation for structural heart disease and pulmonary hypertension should be considered in children with HAPE. Future studies should be done to elucidate the optimal strategies for prevention and treatment of HAPE and to better understand the development of HAPE in children.
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Affiliation(s)
- Deborah R Liptzin
- 1 Breathing Institute and Pediatric Heart-Lung Center, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado , Aurora, Colorado
| | - Steven H Abman
- 1 Breathing Institute and Pediatric Heart-Lung Center, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado , Aurora, Colorado
| | - Ann Giesenhagen
- 2 Heart Institute and Pediatric Heart-Lung Center, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado , Aurora, Colorado
| | - D Dunbar Ivy
- 2 Heart Institute and Pediatric Heart-Lung Center, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado , Aurora, Colorado
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99
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Frlic O, Seliškar A, Domanjko Petrič A, Blagus R, Heigenhauser G, Vengust M. Pulmonary Circulation Transvascular Fluid Fluxes Do Not Change during General Anesthesia in Dogs. Front Physiol 2018. [PMID: 29515463 PMCID: PMC5826326 DOI: 10.3389/fphys.2018.00124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
General anesthesia (GA) can cause abnormal lung fluid redistribution. Pulmonary circulation transvascular fluid fluxes (JVA) are attributed to changes in hydrostatic forces and erythrocyte volume (EV) regulation. Despite the very low hydraulic conductance of pulmonary microvasculature it is possible that GA may affect hydrostatic forces through changes in pulmonary vascular resistance (PVR), and EV through alteration of erythrocyte transmembrane ion fluxes (ionJVA). Furosemide (Fur) was also used because of its potential to affect pulmonary hydrostatic forces and ionJVA. A hypothesis was tested that JVA, with or without furosemide treatment, will not change with time during GA. Twenty dogs that underwent castration/ovariectomy were randomly assigned to Fur (n = 10) (4 mg/kg IV) or placebo treated group (Con, n = 10). Baseline arterial (BL) and mixed venous blood were sampled during GA just before treatment with Fur or placebo and then at 15, 30 and 45 min post-treatment. Cardiac output (Q) and pulmonary artery pressure (PAP) were measured. JVA and ionJVA were calculated from changes in plasma protein, hemoglobin, hematocrit, plasma and whole blood ions, and Q. Variables were analyzed using random intercept mixed model (P < 0.05). Data are expressed as means ± SE. Furosemide caused a significant volume depletion as evident from changes in plasma protein and hematocrit (P < 0.001). However; Q, PAP, and JVA were not affected by time or Fur, whereas erythrocyte fluid flux was affected by Fur (P = 0.03). Furosemide also affected erythrocyte transmembrane K+ and Cl−, and transvascular Cl− metabolism (P ≤ 0.05). No other erythrocyte transmembrane or transvascular ion fluxes were affected by time of GA or Fur. Our hypothesis was verified as JVA was not affected by GA or ion metabolism changes due to Fur treatment. Furosemide and 45 min of GA did not cause significant hydrostatic changes based on Q and PAP. Inhibition of Na+/K+/2Cl− cotransport caused by Fur treatment, which can alter EV regulation and JVA, was offset by the Jacobs Stewart cycle. The results of this study indicate that the Jacobs Stewart cycle/erythrocyte Cl− metabolism can also act as a safety factor for the stability of lung fluid redistribution preserving optimal diffusion distance across the blood gas barrier.
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Affiliation(s)
- Olga Frlic
- Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Alenka Seliškar
- Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
| | | | - Rok Blagus
- Institute for Biostatistics and Medical Informatics, University of Ljubljana, Ljubljana, Slovenia
| | - George Heigenhauser
- Department of Medicine, McMaster University Medical Centre Hamilton, Hamilton, ON, Canada
| | - Modest Vengust
- Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
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Faoro V, Deboeck G, Vicenzi M, Gaston AF, Simaga B, Doucende G, Hapkova I, Roca E, Subirats E, Durand F, Naeije R. Pulmonary Vascular Function and Aerobic Exercise Capacity at Moderate Altitude. Med Sci Sports Exerc 2018; 49:2131-2138. [PMID: 28915226 DOI: 10.1249/mss.0000000000001320] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE There has been suggestion that a greater "pulmonary vascular reserve" defined by a low pulmonary vascular resistance (PVR) and a high lung diffusing capacity (DL) allow for a superior aerobic exercise capacity. How pulmonary vascular reserve might affect exercise capacity at moderate altitude is not known. METHODS Thirty-eight healthy subjects underwent an exercise stress echocardiography of the pulmonary circulation, combined with measurements of DL for nitric oxide (NO) and carbon monoxide (CO) and a cardiopulmonary exercise test at sea level and at an altitude of 2250 m. RESULTS At rest, moderate altitude decreased arterial oxygen content (CaO2) from 19.1 ± 1.6 to 18.4 ± 1.7 mL·dL, P < 0.001, and slightly increased PVR, DLNO, and DLCO. Exercise at moderate altitude was associated with decreases in maximum O2 uptake (V˙O2max), from 51 ± 9 to 43 ± 8 mL·kg⋅min, P < 0.001, and CaO2 to 16.5 ± 1.7 mL·dL, P < 0.001, but no different cardiac output, PVR, and pulmonary vascular distensibility. DLNO was inversely correlated to the ventilatory equivalent of CO2 (V˙E/V˙CO2) at sea level and at moderate altitude. Independent determinants of V˙O2max as determined by a multivariable analysis were the slope of mean pulmonary artery pressure-cardiac output relationship, resting stroke volume, and resting DLNO at sea level as well as at moderate altitude. The magnitude of the decrease in V˙O2max at moderate altitude was independently predicted by more pronounced exercise-induced decrease in CaO2 at moderate altitude. CONCLUSION Aerobic exercise capacity is similarly modulated by pulmonary vascular reserve at moderate altitude and at sea level. Decreased aerobic exercise capacity at moderate altitude is mainly explained by exercise-induced decrease in arterial oxygenation.
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Affiliation(s)
- Vitalie Faoro
- 1Laboratory of Exercise Physiology, Faculty of Motor Sciences, Université Libre de Bruxelles, Brussels, BELGIUM; 2Department of Cardiology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, BELGIUM; 3U.O.C. Cardiovascular Diseases, Fondazione IRCCS Granda Hospital Maggiore Policlinico, Milan, ITALY; 4European Laboratory of Performance Health and Altitude, University of Perpignan, Font-Romeu, FRANCE; 5Faculty of Medicine, University of Girona, Girona, SPAIN; and 6Hospital Transfronterer de Cerdanya, Puigcerdà, SPAIN
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