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Shapiro I, Stein J, MacRae C, O'Reilly M. Pulse oximetry values from 33,080 participants in the Apple Heart & Movement Study. NPJ Digit Med 2023; 6:134. [PMID: 37500721 PMCID: PMC10374661 DOI: 10.1038/s41746-023-00851-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 05/24/2023] [Indexed: 07/29/2023] Open
Abstract
Wearable devices that include pulse oximetry (SpO2) sensing afford the opportunity to capture oxygen saturation measurements from large cohorts under naturalistic conditions. We report here a cross-sectional analysis of 72 million SpO2 values collected from 33,080 individual participants in the Apple Heart and Movement Study, stratified by age, sex, body mass index (BMI), home altitude, and other demographic variables. Measurements aggregated by hour of day into 24-h SpO2 profiles exhibit similar circadian patterns for all demographic groups, being approximately sinusoidal with nadir near midnight local time, zenith near noon local time, and mean 0.8% lower saturation during overnight hours. Using SpO2 measurements averaged for each subject into mean nocturnal and daytime SpO2 values, we employ multivariate ordinary least squares regression to quantify population-level trends according to demographic factors. For the full cohort, regression coefficients obtained from models fit to daytime SpO2 are in close quantitative agreement with the corresponding values from published reference models for awake arterial oxygen saturation measured under controlled laboratory conditions. Regression models stratified by sex reveal significantly different age- and BMI-dependent SpO2 trends for females compared with males, although constant terms and regression coefficients for altitude do not differ between sexes. Incorporating categorical variables encoding self-reported race/ethnicity into the full-cohort regression models identifies small but statistically significant differences in daytime SpO2 (largest coefficient corresponding to 0.13% lower SpO2, for Hispanic study participants compared to White participants), but no significant differences between groups for nocturnal SpO2. Additional stratified analysis comparing regression models fit independently to subjects in each race/ethnicity group is suggestive of small differences in age- and sex-dependent trends, but indicates no significant difference in constant terms between any race/ethnicity groups for either daytime or nocturnal SpO2. The large diverse study population and study design employing automated background SpO2 measurements spanning the full 24-h circadian cycle enables the establishment of healthy population reference trends outside of clinical settings.
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Affiliation(s)
| | | | - Calum MacRae
- Cardiovascular Medicine Division, Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
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Riveros-Rivera A, Penzel T, Gunga HC, Opatz O, Paul F, Klug L, Boschmann M, Mähler A. Hypoxia Differentially Affects Healthy Men and Women During a Daytime Nap With a Dose-Response Relationship: a Randomized, Cross-Over Pilot Study. Front Physiol 2022; 13:899636. [PMID: 35685284 PMCID: PMC9171024 DOI: 10.3389/fphys.2022.899636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Context: The use of daytime napping as a countermeasure in sleep disturbances has been recommended but its physiological evaluation at high altitude is limited. Objective: To evaluate the neuroendocrine response to hypoxic stress during a daytime nap and its cognitive impact. Design, Subject, and Setting: Randomized, single-blind, three period cross-over pilot study conducted with 15 healthy lowlander subjects (8 women) with a mean (SD) age of 29(6) years (Clinicaltrials identifier: NCT04146857, https://clinicaltrials.gov/ct2/show/NCT04146857?cond=napping&draw=3&rank=12). Interventions: Volunteers underwent a polysomnography, hematological and cognitive evaluation around a 90 min midday nap, being allocated to a randomized sequence of three conditions: normobaric normoxia (NN), normobaric hypoxia at FiO2 14.7% (NH15) and 12.5% (NH13), with a washout period of 1 week between conditions. Results: Primary outcome was the interbeat period measured by the RR interval with electrocardiogram. Compared to normobaric normoxia, RR during napping was shortened by 57 and 206 ms under NH15 and NH13 conditions, respectively (p < 0.001). Sympathetic predominance was evident by heart rate variability analysis and increased epinephrine levels. Concomitantly, there were significant changes in endocrine parameters such as erythropoietin (∼6 UI/L) and cortisol (∼100 nmol/L) (NH13 vs. NN, p < 0.001). Cognitive evaluation revealed changes in the color-word Stroop test. Additionally, although sleep efficiency was preserved, polysomnography showed lesser deep sleep and REM sleep, and periodic breathing, predominantly in men. Conclusion: Although napping in simulated altitude does not appear to significantly affect cognitive performance, sex-dependent changes in cardiac autonomic modulation and respiratory pattern should be considered before napping is prescribed as a countermeasure.
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Affiliation(s)
- Alain Riveros-Rivera
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Physiological Sciences, Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Thomas Penzel
- Interdisciplinary Center of Sleep Medicine, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Hanns-Christian Gunga
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Oliver Opatz
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Friedemann Paul
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Lars Klug
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Michael Boschmann
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Anja Mähler
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
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3
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Adamovich Y, Dandavate V, Asher G. Circadian clocks' interactions with oxygen sensing and signalling. Acta Physiol (Oxf) 2022; 234:e13770. [PMID: 34984824 DOI: 10.1111/apha.13770] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/14/2021] [Accepted: 01/01/2022] [Indexed: 12/14/2022]
Abstract
In mammals, physiology and metabolism are shaped both by immediate and anticipatory responses to environmental changes through the myriad of molecular mechanisms. Whilst the former is mostly mediated through different acute signalling pathways the latter is primarily orchestrated by the circadian clock. Oxygen is vital for life and as such mammals have evolved different mechanisms to cope with changes in oxygen levels. It is widely accepted that oxygen sensing through the HIF-1 signalling pathway is paramount for the acute response to changes in oxygen levels. Circadian clocks are molecular oscillators that control 24 hours rhythms in various aspects of physiology and behaviour. Evidence emerging in recent years points towards pervasive molecular and functional interactions between these two pathways on multiple levels. Daily oscillations in oxygen levels are circadian clock-controlled and can reset the clock through HIF-1. Furthermore, the circadian clock appears to modulate the hypoxic response. We review herein the literature related to the crosstalk between the circadian clockwork and the oxygen-signalling pathway in mammals at the molecular and physiological level both under normal and pathologic conditions.
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Affiliation(s)
- Yaarit Adamovich
- Department of Biomolecular Sciences Weizmann Institute of Science Rehovot Israel
| | - Vaishnavi Dandavate
- Department of Biomolecular Sciences Weizmann Institute of Science Rehovot Israel
| | - Gad Asher
- Department of Biomolecular Sciences Weizmann Institute of Science Rehovot Israel
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Imtiaz MS, Bandoian CV, Santoro TJ. Hypoxia driven opioid targeted automated device for overdose rescue. Sci Rep 2021; 11:24513. [PMID: 34972818 PMCID: PMC8720093 DOI: 10.1038/s41598-021-04094-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/13/2021] [Indexed: 11/27/2022] Open
Abstract
Opioid use disorder has been designated a worsening epidemic with over 100,000 deaths due to opioid overdoses recorded in 2021 alone. Unintentional deaths due to opioid overdoses have continued to rise inexorably. While opioid overdose antidotes such as naloxone, and nalmefene are available, these must be administered within a critical time window to be effective. Unfortunately, opioid-overdoses may occur in the absence of antidote, or may be unwitnessed, and the rapid onset of cognitive impairment and unconsciousness, which frequently accompany an overdose may render self-administration of an antidote impossible. Thus, many lives are lost because: (1) an opioid overdose is not anticipated (i.e., monitored/detected), and (2) antidote is either not present, and/or not administered within the critical frame of effectiveness. Currently lacking is a non-invasive means of automatically detecting, reporting, and treating such overdoses. To address this problem, we have designed a wearable, on-demand system that comprises a safe, compact, non-invasive device which can monitor, and effectively deliver an antidote without human intervention, and report the opioid overdose event. A novel feature of our device is a needle-stow chamber that stores needles in a sterile state and inserts needles into tissue only when drug delivery is needed. The system uses a microcontroller which continuously monitors respiratory status as assessed by reflex pulse oximetry. When the oximeter detects the wearer’s percentage of hemoglobin saturated with oxygen to be less than or equal to 90%, which is an indication of impending respiratory failure in otherwise healthy individuals, the microcontroller initiates a sequence of events that simultaneously results in the subcutaneous administration of opioid antidote, nalmefene, and transmission of a GPS-trackable 911 alert. The device is compact (4 × 3 × 3 cm), adhesively attaches to the skin, and can be conveniently worn on the arm. Furthermore, this device permits a centralized remotely accessible system for effective institutional, large-scale intervention. Most importantly, this device has the potential for saving lives that are currently being lost to an alarmingly increasing epidemic.
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Fehrenbacher K, Apel C, Bertsch D, van der Giet MS, van der Giet S, Grass M, Gschwandtl C, Heussen N, Hundt N, Kühn C, Morrison A, Müller-Ost M, Müller-Tarpet M, Porath S, Risse J, Schmitz S, Schöffl V, Timmermann L, Wernitz K, Küpper T. Temporary threshold shift after noise exposure in hypobaric hypoxia at high altitude: results of the ADEMED expedition 2011. Int Arch Occup Environ Health 2021; 94:1191-1199. [PMID: 34023963 PMCID: PMC8292300 DOI: 10.1007/s00420-021-01715-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 08/29/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To evaluate whether there is an increased risk for noise-induced hearing loss at high altitude rsp. in hypobaric hypoxia. METHODS Thirteen volunteers got standard audiometry at 125, 250, 500, 750, 1000, 1500, 2000, 3000, 4000, 6000, and 8000 Hz before and after 10 min of white noise at 90 dB. The system was calibrated for the respective altitude. Measurements were performed at Kathmandu (1400 m) and at Gorak Shep (5300 m) (Solo Khumbu/Nepal) after 10 days of acclimatization while on trek. Temporary threshold shift (TTS) was analyzed by descriptive statistics and by factor analysis. RESULTS TTS is significantly more pronounced at high altitudes. Acclimatization does not provide any protection of the inner ear, although it increases arterial oxygen saturation. CONCLUSION The thresholds beyond which noise protection is recommended (> 80 dB) or necessary (> 85 dB) are not sufficient at high altitudes. We suggest providing protective devices above an altitude of 1500 m ("ear threshold altitude") when noise level is higher than 75 dB and using them definitively above 80 dB. This takes the individual reaction on hypobaric hypoxia at high altitude into account.
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Affiliation(s)
- K Fehrenbacher
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - C Apel
- Department of Dental Preservation, Parodontology and Preventive Dentistry, RWTH Aachen Technical University, Aachen, Germany
| | - D Bertsch
- Department of Cardiology, Catholic Hospital Marienhof, Koblenz, Germany
| | - M S van der Giet
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - S van der Giet
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - M Grass
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - C Gschwandtl
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - N Heussen
- Department of Medical Statistics, RWTH Aachen Technical University, Aachen, Germany
- Medical School, Sigmund Freud Private University, Vienna, Austria
| | - N Hundt
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - C Kühn
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - A Morrison
- Royal Free London NHS Foundation Trust, London, UK
| | - M Müller-Ost
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - M Müller-Tarpet
- Department of Technical Acoustics, RWTH Aachen University, Aachen, Germany
| | - S Porath
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - J Risse
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - S Schmitz
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - V Schöffl
- Medical Commission of the Union Internationale des Associations d'Alpinisme (UIAA MedCom), Bern, Switzerland
- Department of Sports Medicine-Sports Orthopaedics, Klinikum Bamberg, Bamberg, Germany
- Department of Trauma Surgery, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - L Timmermann
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - K Wernitz
- Department of Dental Preservation, Parodontology and Preventive Dentistry, RWTH Aachen Technical University, Aachen, Germany
| | - T Küpper
- Institute of Occupational and Social Medicine, RWTH Aachen Technical University, Pauwelsstr. 30, 52074, Aachen, Germany.
- Medical Commission of the Union Internationale des Associations d'Alpinisme (UIAA MedCom), Bern, Switzerland.
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The circadian clock regulates rhythmic erythropoietin expression in the murine kidney. Kidney Int 2021; 100:1071-1080. [PMID: 34332958 DOI: 10.1016/j.kint.2021.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 06/28/2021] [Accepted: 07/02/2021] [Indexed: 11/23/2022]
Abstract
Generation of circadian rhythms is cell-autonomous and relies on a transcription/translation feedback loop controlled by a family of circadian clock transcription factor activators including CLOCK, BMAL1 and repressors such as CRY1 and CRY2. The aim of the present study was to examine both the molecular mechanism and the hemopoietic implication of circadian erythropoietin expression. Mutant mice with homozygous deletion of the core circadian clock genes cryptochromes 1 and 2 (Cry-null) were used to elucidate circadian erythropoietin regulation. Wild-type control mice exhibited a significant difference in kidney erythropoietin mRNA expression between circadian times 06 and 18. In parallel, a significantly higher number of erythropoietin-producing cells in the kidney (by RNAscope®) and significantly higher levels of circulating erythropoietin protein (by ELISA) were detected at circadian time 18. Such changes were abolished in Cry-null mice and were independent from oxygen tension, oxygen saturation, or expression of hypoxia-inducible factor 2 alpha, indicating that circadian erythropoietin expression is transcriptionally regulated by CRY1 and CRY2. Reporter gene assays showed that the CLOCK/BMAL1 heterodimer activated an E-box element in the 5' erythropoietin promoter. RNAscope® in situ hybridization confirmed the presence of Bmal1 in erythropoietin-producing cells of the kidney. In Cry-null mice, a significantly reduced number of reticulocytes was found while erythrocyte numbers and hematocrit were unchanged. Thus, circadian erythropoietin regulation in the normoxic adult murine kidney is transcriptionally controlled by master circadian activators CLOCK/BMAL1, and repressors CRY1/CRY2. These findings may have implications for kidney physiology and disease, laboratory diagnostics, and anemia therapy.
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7
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Mancera-Soto E, Ramos-Caballero DM, Magalhaes J, Chaves Gomez S, Schmidt WFJ, Cristancho-Mejía E. Quantification of testosterone-dependent erythropoiesis during male puberty. Exp Physiol 2021; 106:1470-1481. [PMID: 33945170 DOI: 10.1113/ep089433] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/28/2021] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? To what extent does testosterone influence haemoglobin formation during male puberty? What is the main finding and its importance? In boys, testosterone might be responsible for about 65% of the increase in haemoglobin mass during puberty. The underlying mechanisms are assumed to be twofold: (i) indirectly, mediated by the increase in lean body mass, and (ii) directly by immediate testosterone effects on erythropoiesis. Thereby, an increase in testosterone of 1 ng/ml is associated with an increase in haemoglobin mass of ∼65 g. These processes are likely to determine endurance performance in adulthood. ABSTRACT The amount of haemoglobin during puberty is related to endurance performance in adulthood. During male puberty, testosterone stimulates erythropoiesis and could therefore be used as a marker for later endurance performance. This cross-sectional study aimed to determine the relationship between serum testosterone concentration and haemoglobin mass (Hbmass) in both male and female children and adolescents and to evaluate the possible influences of altitude and training. Three-hundred and thirteen differentially trained boys and girls aged from 9 to 18 years and living at altitudes of 1000 and 2600 m above sea level entered the study. The stage of sexual maturation was determined according to the classification of Tanner. Testosterone was measured by ELISA. Hbmass was determined by CO-rebreathing. Haemoglobin concentration did not change during maturation in girls and was 11% higher during puberty in boys, while Hbmass was elevated by 33% in Tanner stage V compared to stage II in girls (498 ± 77 vs. 373 ± 88 g) and by 95% in boys (832 ± 143 vs. 428 ± 95 g). This difference can most likely be attributed to indirect testosterone influences through an increase in lean body mass (LBM) and to direct testosterone effects on erythropoiesis, which increase the Hbmass by ∼65 g per 1 ng/ml. Altitude and training statuses were not associated with testosterone, but with an increase in Hbmass (altitude by 1.1 g/kg LBM, training by 0.8 g/kg LBM). Changes in Hbmass are closely related to testosterone levels during male puberty. Further studies will show whether testosterone and Hbmass during childhood and adolescence can be used as diagnostic tools for endurance talents.
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Affiliation(s)
- Erica Mancera-Soto
- Departamento del Movimiento Corporal Humano, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia.,Department of Sports Medicine and Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | | | - Jose Magalhaes
- Laboratory of Metabolism and Exercise (LaMetEx) Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport (FADEUP), University of Porto, Porto, Portugal
| | - Sandra Chaves Gomez
- Laboratorio de Control al Dopaje, Ministerio del Deporte de Colombia, Bogotá, Colombia
| | - Walter F J Schmidt
- Department of Sports Medicine and Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Edgar Cristancho-Mejía
- Departamento de Biología, Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia
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8
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Abstract
Although kidney oxygen tensions are heterogenous, and mostly below renal vein level, the nephron is highly dependent on aerobic metabolism for active tubular transport. This renders the kidney particularly susceptible to hypoxia, which is considered a main characteristic and driver of acute and chronic kidney injury, albeit the evidence supporting this assumption is not entirely conclusive. Kidney transplants are exposed to several conditions that may interfere with the balance between oxygen supply and consumption, and enhance hypoxia and hypoxic injury. These include conditions leading to and resulting from brain death of kidney donors, ischemia and reperfusion during organ donation, storage and transplantation, postoperative vascular complications, vasoconstriction induced by immunosuppression, and impaired perfusion resulting from interstitial edema, inflammation, and fibrosis. Acute graft injury, the immediate consequence of hypoxia and reperfusion, results in delayed graft function and increased risk of chronic graft failure. Although current strategies to alleviate hypoxic/ischemic graft injury focus on limiting injury (eg, by reducing cold and warm ischemia times), experimental evidence suggests that preconditioning through local or remote ischemia, or activation of the hypoxia-inducible factor pathway, can decrease hypoxic injury. In combination with ex vivo machine perfusion such approaches hold significant promise for improving transplantation outcomes.
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Affiliation(s)
- Christian Rosenberger
- Department of Nephrology and Medical Intensive Care, Charité Universitaetsmedizin Berlin, Berlin, Germany.
| | - Kai-Uwe Eckardt
- Department of Nephrology and Medical Intensive Care, Charité Universitaetsmedizin Berlin, Berlin, Germany
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9
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Gassmann M, Mairbäurl H, Livshits L, Seide S, Hackbusch M, Malczyk M, Kraut S, Gassmann NN, Weissmann N, Muckenthaler MU. The increase in hemoglobin concentration with altitude varies among human populations. Ann N Y Acad Sci 2019; 1450:204-220. [PMID: 31257609 DOI: 10.1111/nyas.14136] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/02/2019] [Accepted: 05/16/2019] [Indexed: 02/06/2023]
Abstract
Decreased oxygen availability at high altitude requires physiological adjustments allowing for adequate tissue oxygenation. One such mechanism is a slow increase in the hemoglobin concentration ([Hb]) resulting in elevated [Hb] in high-altitude residents. Diagnosis of anemia at different altitudes requires reference values for [Hb]. Our aim was to establish such values based on published data of residents living at different altitudes by applying meta-analysis and multiple regressions. Results show that [Hb] is increased in all high-altitude residents. However, the magnitude of increase varies among the regions analyzed and among ethnic groups within a region. The highest increase was found in residents of the Andes (1 g/dL/1000 m), but this increment was smaller in all other regions of the world (0.6 g/dL/1000 m). While sufficient data exist for adult males and females showing that sex differences in [Hb] persist with altitude, data for infants, children, and pregnant women are incomplete preventing such analyses. Because WHO reference values were originally based on [Hb] of South American people, we conclude that individual reference values have to be defined for ethnic groups to reliably diagnose anemia and erythrocytosis in high-altitude residents. Future studies need to test their applicability for children of different ages and pregnant women.
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Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Heimo Mairbäurl
- Translational Lung Research Center Heidelberg (TLRC), the German Center for Lung Research (DZL), Heidelberg, Germany
| | - Leonid Livshits
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Svenja Seide
- Institute of Medical Biometry and Informatics (IMBI), University Hospital Heidelberg, Heidelberg, Germany
| | - Matthes Hackbusch
- Institute of Medical Biometry and Informatics (IMBI), University Hospital Heidelberg, Heidelberg, Germany
| | - Monika Malczyk
- Excellence Cluster Cardiopulmonary System, Justus-Liebig-University Giessen, University of Giessen and Marburg Lung Center, German Center for Lung Research (DZL), Heidelberg, Germany
| | - Simone Kraut
- Excellence Cluster Cardiopulmonary System, Justus-Liebig-University Giessen, University of Giessen and Marburg Lung Center, German Center for Lung Research (DZL), Heidelberg, Germany
| | - Norina N Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Norbert Weissmann
- Excellence Cluster Cardiopulmonary System, Justus-Liebig-University Giessen, University of Giessen and Marburg Lung Center, German Center for Lung Research (DZL), Heidelberg, Germany
| | - Martina U Muckenthaler
- Pediatric Hematology, Oncology and Immunology, University Hospital Heidelberg, Molecular Medicine Partnership Unit, University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research, Heidelberg, Germany
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10
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The correct measurement of oxygen saturation at high altitude. Sleep Breath 2019; 23:1101-1106. [DOI: 10.1007/s11325-019-01784-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 01/09/2019] [Accepted: 01/17/2019] [Indexed: 10/27/2022]
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11
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Li N, Li HP, Wang P, Yan YR, Li SQ, Li QY. Nocturnal Mean Oxygen Saturation Is Associated with Secondary Polycythemia in Young Adults with Obstructive Sleep Apnea, Especially in Men. Nat Sci Sleep 2019; 11:377-386. [PMID: 31824198 PMCID: PMC6901050 DOI: 10.2147/nss.s226143] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/18/2019] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE Whether the severity of obstructive sleep apnea (OSA) contributes to clinical polycythemia is uncertain, especially in young adults. This study aimed to assess the correlation between untreated OSA and polycythemia, controlling for multiple confounders, and to observe the difference in both genders. METHODS All participants underwent nocturnal polysomnography. Medical comorbidities, and demographic and laboratory information were also recorded. The relationship between OSA and concomitant polycythemia in both genders was analyzed. RESULTS A total of 605 young participants (383 men and 222 women), aged 30.52 ± 7.21 years, were enrolled, with an average body mass index of 32.48 ± 6.06 kg/m2. Although 74.4% of patients were diagnosed with OSA, less than 10% had polycythemia. The levels of hemoglobin and hematocrit increased with the severity of OSA; only men with severe OSA had significantly higher hemoglobin, hematocrit, and polycythemia compared with those in the control group (P < 0.01). Hemoglobin and hematocrit significantly correlated with mean pulse oxygen saturation (SpO2) (P < 0.001), but the correlation coefficients were weaker in women than in men. In logistic regression analysis, mean SpO2, but not the apnea-hypopnea index (AHI), was found to be an independent predictor of polycythemia (P < 0.05). Areas under the receive operator characteristic analysis revealed that the cutoff values of hemoglobin and hematocrit were 155.5g/L and 44.6% (P < 0.001), respectively, for assessing nocturnal hypoxemia in men with OSA. CONCLUSION Nocturnal mean SpO2 was an independent predictor of polycythemia in young adults. Mean SpO2, compared with the AHI, was more associated with polycythemia. Men were more prone to suffer from polycythemia compared with women. Hemoglobin and hematocrit values might have diagnostic utility for assessing nocturnal hypoxia severity of OSA patients, especially in men.
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Affiliation(s)
- Ning Li
- Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Hong Peng Li
- Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Ping Wang
- Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Ya Ru Yan
- Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Shi Qi Li
- Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Qing Yun Li
- Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Disease, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
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12
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Hoffmeister T, Schwenke D, Wachsmuth N, Krug O, Thevis M, Byrnes WC, Schmidt WF. Erythropoietic effects of low-dose cobalt application. Drug Test Anal 2018; 11:200-207. [DOI: 10.1002/dta.2478] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 06/04/2018] [Accepted: 08/01/2018] [Indexed: 11/05/2022]
Affiliation(s)
- Torben Hoffmeister
- Department of Sports Medicine/Sports Physiology; University of Bayreuth; Germany
| | - Dirk Schwenke
- Institute of Doping Analysis and Sports Biochemistry; University of Dresden; Germany
| | - Nadine Wachsmuth
- Department of Sports Medicine/Sports Physiology; University of Bayreuth; Germany
| | - Oliver Krug
- Institute of Biochemistry; German Sports University; Cologne Germany
| | - Mario Thevis
- Institute of Biochemistry; German Sports University; Cologne Germany
| | - William C. Byrnes
- Department of Integrative Physiology; University of Colorado; Boulder Colorado USA
| | - Walter F.J. Schmidt
- Department of Sports Medicine/Sports Physiology; University of Bayreuth; Germany
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13
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Abstract
The kidneys regulate many vital functions that require precise control throughout the day. These functions, such as maintaining sodium balance or regulating arterial pressure, rely on an intrinsic clock mechanism that was commonly believed to be controlled by the central nervous system. Mounting evidence in recent years has unveiled previously underappreciated depth of influence by circadian rhythms and clock genes on renal function, at the molecular and physiological level, independent of other external factors. The impact of circadian rhythms in the kidney also affects individuals from a clinical standpoint, as the loss of rhythmic activity or clock gene expression have been documented in various cardiovascular diseases. Fortunately, the prognostic value of examining circadian rhythms may prove useful in determining the progression of a kidney-related disease, and chronotherapy is a clinical intervention that requires consideration of circadian and diurnal rhythms in the kidney. In this review, we discuss evidence of circadian regulation in the kidney from basic and clinical research in order to provide a foundation on which a great deal of future research is needed to expand our understanding of circadian relevant biology.
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Affiliation(s)
- Jermaine G Johnston
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - David M Pollock
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
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Tannheimer M, van der Spek R, Lechner R, Steinacker J, Treff G. Reply to Comment 'Nocturnal decrease of arterial oxygen content-hidden stimulus for erythropoietin secretion at altitude by Böning et al. on Oxygen saturation increases over the course of the night in mountaineers at high altitude (3050m-6354 m) by Tannheimer et al.'. J Travel Med 2018; 25:4780175. [PMID: 29394390 DOI: 10.1093/jtm/tax093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 11/27/2017] [Indexed: 11/14/2022]
Affiliation(s)
- Markus Tannheimer
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, Leimgrubenweg 14, 89075 Ulm, Germany
| | - Rianne van der Spek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, F5-166, Postbus 22660, 1100 DD Amsterdam, The Netherlands
| | - Raimund Lechner
- Department of Anesthesiology, German Armed Forces Hospital Ulm, Oberer Eselsberg 40, 89081 Ulm, Germany
| | - Jürgen Steinacker
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, Leimgrubenweg 14, 89075 Ulm, Germany
| | - Gunnar Treff
- Division of Sports and Rehabilitation Medicine, University Hospital Ulm, Leimgrubenweg 14, 89075 Ulm, Germany
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15
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EPOR 2/βcR 2-independendent effects of low-dose epoetin- α in porcine liver transplantation. Biosci Rep 2017; 37:BSR20171007. [PMID: 29127105 PMCID: PMC5715127 DOI: 10.1042/bsr20171007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 10/31/2017] [Accepted: 11/07/2017] [Indexed: 12/17/2022] Open
Abstract
Ischemia–reperfusion injury (IRI) remains a key component of graft damage during transplantation. Erythropoietin (EPO) induces anti-inflammatory and anti-apoptotic effects via the EPOR2/βcR2 complex, with a potential risk of thrombosis. Previous work indicates that EPO has EPOR2/βcR2-independent protective effects via direct effects on the endothelium. As the EPOR2/βcR2 receptor has a very low affinity for EPO, we aimed to test the hypothesis that EPO doses below the level that stimulate this receptor elicit cytoprotective effects via endothelial stimulation in a porcine liver transplantation model. Landrace pigs underwent allogenic liver transplantation (follow-up: 6 h) with a portojugular shunt. Animals were divided into two groups: donor and recipient treatment with low-dose EPO (65 IU/kg) or vehicle, administered 6 h before cold perfusion and 30 min after warm reperfusion. Fourteen of 17 animals (82.4%) fulfilled the inclusion criteria. No differences were noted in operative values between the groups including hemoglobin, cold or warm ischemic time. EPO-treated animals showed a significantly lower histopathology score, reduced apoptosis, oxidative stress, and most important a significant up-regulation of endothelial nitric oxide (NO) synthase (eNOS). Donor and recipient treatment with low-dose EPO reduces the hepatic IRI via EPOR2/βcR2-independent cytoprotective mechanisms and represents a clinically applicable way to reduce IRI.
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Cristancho E, Riveros A, Sánchez A, Peñuela O, Böning D. Diurnal changes of arterial oxygen saturation and erythropoietin concentration in male and female highlanders. Physiol Rep 2017; 4:4/17/e12901. [PMID: 27597764 PMCID: PMC5027342 DOI: 10.14814/phy2.12901] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/20/2016] [Indexed: 01/27/2023] Open
Abstract
In Caucasians and Native Americans living at altitude, hemoglobin mass is increased in spite of erythropoietin concentrations ([Epo]) not markedly differing from sea level values. We hypothesized that a nocturnal decrease of arterial oxygen saturation (SaO2) causes a temporary rise of [Epo] not detected by morning measurements. SaO2 (continuous, finger oximeter) and [Epo] (ELISA, every 4 h) were determined in young highlanders (altitude 2600 m) during 24 h of usual daily activity. In Series I (six male, nine female students), SaO2 fell during the night with the nadir occurring between 01:00 and 03:00; daily means (range 92.4–95.2%) were higher in females (+1.7%, P < 0.01). [Epo] showed opposite changes with zenith occurring at 04:00 without a sex difference. Mean daily values (22.9 ± 10.7SD U/L) were higher than values obtained at 08:00 (17.2 ± 9.5 U/L, P < 0.05). In Series II (seven females), only SaO2 was measured. During follicular and luteal phases, SaO2 variation was similar to Series I, but the rhythm was disturbed during menstruation. While daily [Epo] variations at sea level are not homogeneous, there is a diurnal variation at altitude following changes in SaO2. Larger hypoventilation‐dependent decreases of alveolar PO2 decreases during the night probably cause a stronger reduction of SaO2 in highlanders compared to lowlanders. This variation might be enlarged by a diurnal fluctuation of Hb concentration. In spite of a lower [Hb], the higher SaO2 in women compared to men led to a similar arterial oxygen content, likely explaining the absence of differences in [Epo] between sexes.
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Affiliation(s)
- Edgar Cristancho
- Departamento de Biologia, Division de Fisiologia Animal, Universidad Nacional de Colombia, Bogotá, Colombia
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