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Mairbäurl H. Squeezing viscous blood through narrow pipes, and other problems of high-altitude polycythaemia. J Physiol 2021; 599:4011-4012. [PMID: 34333786 DOI: 10.1113/jp282104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Heimo Mairbäurl
- Translational Pneumology, University Hospital Heidelberg, Heidelberg, Baden-Wurttemberg, Germany
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2
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Grygorczyk R, Boudreault F, Ponomarchuk O, Tan JJ, Furuya K, Goldgewicht J, Kenfack FD, Yu F. Lytic Release of Cellular ATP: Physiological Relevance and Therapeutic Applications. Life (Basel) 2021; 11:life11070700. [PMID: 34357072 PMCID: PMC8307140 DOI: 10.3390/life11070700] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/28/2021] [Accepted: 07/13/2021] [Indexed: 01/01/2023] Open
Abstract
The lytic release of ATP due to cell and tissue injury constitutes an important source of extracellular nucleotides and may have physiological and pathophysiological roles by triggering purinergic signalling pathways. In the lungs, extracellular ATP can have protective effects by stimulating surfactant and mucus secretion. However, excessive extracellular ATP levels, such as observed in ventilator-induced lung injury, act as a danger-associated signal that activates NLRP3 inflammasome contributing to lung damage. Here, we discuss examples of lytic release that we have identified in our studies using real-time luciferin-luciferase luminescence imaging of extracellular ATP. In alveolar A549 cells, hypotonic shock-induced ATP release shows rapid lytic and slow-rising non-lytic components. Lytic release originates from the lysis of single fragile cells that could be seen as distinct spikes of ATP-dependent luminescence, but under physiological conditions, its contribution is minimal <1% of total release. By contrast, ATP release from red blood cells results primarily from hemolysis, a physiological mechanism contributing to the regulation of local blood flow in response to tissue hypoxia, mechanical stimulation and temperature changes. Lytic release of cellular ATP may have therapeutic applications, as exemplified by the use of ultrasound and microbubble-stimulated release for enhancing cancer immunotherapy in vivo.
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Affiliation(s)
- Ryszard Grygorczyk
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
- Département de Médecine, Université de Montréal, Montréal, QC H2X 0A9, Canada
- Correspondence: (R.G.); (F.Y.)
| | - Francis Boudreault
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Olga Ponomarchuk
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Ju Jing Tan
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Kishio Furuya
- Graduate School of Medicine, Nagoya University, Nagoya 464-8601, Japan;
| | - Joseph Goldgewicht
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Falonne Démèze Kenfack
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - François Yu
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
- Département de Radiologie, Radio-Oncologie et Médecine Nucléaire, Université de Montréal, Montréal, QC H2X 0A9, Canada
- Institut de Génie Biomédical, Université de Montréal, Montréal, QC H2X 0A9, Canada
- Correspondence: (R.G.); (F.Y.)
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3
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Magliulo L, Bondi D, Pietrangelo T, Fulle S, Piccinelli R, Jandova T, Blasio GD, Taraborrelli M, Verratti V. Serum ferritin and vitamin D evaluation in response to high altitude comparing Italians trekkers vs Nepalese porters. Eur J Sport Sci 2020; 21:994-1002. [PMID: 32627691 DOI: 10.1080/17461391.2020.1792559] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Altitude hypoxia induces changes in iron homeostasis with serum ferritin (sFER) response being recently linked to erythropoiesis. The main aim of this study was to investigate sFER and Vitamin D (Vit D) response to hypobaric hypoxia, taking into account factors including nutrition and ethnic origin. As part of a "Kanchenjunga Exploration & Physiology" project, 6 Italian trekkers and 6 Nepalese porters took part in a 19-days long altitude trek in the Himalayas self-recording daily food consumption. Blood samples were collected and analyzed before and after the trek for sFER and Vit D. A web-based system calculated the dietary intake, generating reports that were used for later statistical analyses. sFER decreased after the trek (on average by 26% p = 0.013, partial η2 = 0.479) in both groups, whereas Vit D did not change in both groups. Nepalese tended to have lower sFER, but this difference was reduced when corrected for the dietary intake. Mean Cell Volume (MCV) and Hematocrit (HCT), in respect to baseline, remained higher 10 days after the trek (respectively, 87.37-88.85 fL with p = 0.044, and 43.05-44.63% with p = 0.065) in Italian trekkers. The observed reduction of sFER levels was related to altitude per se as inflammation or anemia were medically excluded. sFER, therefore, may act as a primary factor in the examination of hypobaric hypoxia in field studies. The results of this study open a new door into the mechanisms of iron homeostasis in specific tissues related to hypoxia adaptations, taking into account dietary intake and ethnic origin.
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Affiliation(s)
- Laura Magliulo
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti, Italy
| | - Danilo Bondi
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti, Italy
| | - Tiziana Pietrangelo
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti, Italy
| | - Stefania Fulle
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti, Italy
| | - Raffaela Piccinelli
- Council for Agricultural Research and Economics, Research Centre for Food and Nutrition, Rome, Italy
| | - Tereza Jandova
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti, Italy
| | | | - Mattia Taraborrelli
- Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti, Italy
| | - Vittore Verratti
- Department of Psychological, Health and Territorial Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti, Italy
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4
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Morris KL, Widstrom L, Goodrich J, Poddar S, Rueda M, Holliday M, San Millian I, Byrnes WC. A Retrospective Analysis of Collegiate Athlete Blood Biomarkers at Moderate Altitude. J Strength Cond Res 2019; 33:2913-2919. [DOI: 10.1519/jsc.0000000000003352] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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5
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Hoffman JF. Reflections on the crooked timber of red blood cell physiology. Blood Cells Mol Dis 2019; 79:102354. [PMID: 31449971 DOI: 10.1016/j.bcmd.2019.102354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 08/16/2019] [Indexed: 01/07/2023]
Affiliation(s)
- Joseph F Hoffman
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, United States.
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6
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Sierra APR, Oliveira RA, Silva ED, Lima GHO, Benetti MP, Kiss MAP, Sierra CA, Ghorayeb N, Seto JT, Pesquero JB, Cury-Boaventura MF. Association Between Hematological Parameters and Iron Metabolism Response After Marathon Race and ACTN3 Genotype. Front Physiol 2019; 10:697. [PMID: 31244673 PMCID: PMC6580990 DOI: 10.3389/fphys.2019.00697] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/17/2019] [Indexed: 12/19/2022] Open
Abstract
α-Actinin-3 (ACTN3 R577X, rs.1815739) polymorphism is a genetic variation that shows the most consistent influence on metabolic pathway and muscle phenotype. XX genotype is associated with higher metabolic efficiency of skeletal muscle; however, the role of ACTN3 polymorphism in oxygen transport and utilization system has not yet been investigated. Therefore, the aim of this study was to determine the influence of ACTN3 polymorphisms on hematological and iron metabolism response induced by marathon race. Eighty-one Brazilian amateur male endurance runners participated in the study. Blood samples and urine were collected before; immediately after; and 1, 3, and 15 days after the marathon race. Urine, hematological parameters, iron metabolism, and ACTN3 genotyping analyses were performed. The marathon race induced a decrease in erythrocytes, Hb, and Ht, and an increase in hematuria, creatinine, myoglobin, red cell distribution width, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, direct and indirect bilirubin and erythropoietin. Moreover, an elevation immediately or 1 day after the marathon race follows a reduction 3 or 15 days after the marathon race were observed on transferrin saturation and iron and transferrin levels. Hematological parameters and iron metabolism changes induced by marathon race were not observed in XX genotypes. Hematuria and decreased erythrocytes, Hb, Ht, and iron and transferrin levels were observed only in RR and/or RX genotypes but not in XX genotypes. The percentage of runners with hematuria, leukocyturia, iron deficiency, creatinine, myoglobin, and bilirubin imbalance was higher in RR compared to XX genotypes. ACTN3 polymorphism is associated with iron metabolism and hematological responses after endurance exercise. Despite these results being based on a small sample, they highlight a protective role of the XX genotype on hematological and renal changes induced by long-distance exercise. Therefore, these findings should be further replicated.
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Affiliation(s)
- Ana Paula Renno Sierra
- Department of Biodynamics of Human Movements, School of Physical Education and Sports, University of São Paulo, São Paulo, Brazil.,Sports Cardiology Department, Dante Pazzanese Institute of Cardiology, São Paulo, Brazil
| | - Rodrigo Assunção Oliveira
- Department of Interdisciplinary in Health Sciences, Institute of Physical Activity and Sports Sciences, Cruzeiro do Sul University, São Paulo, Brazil
| | - Elton Dias Silva
- Department of Biophysics, Federal University of São Paulo, São Paulo, Brazil
| | - Giscard Humberto Oliveira Lima
- Department of Biophysics, Federal University of São Paulo, São Paulo, Brazil.,Department of Movement, Human and Health Sciences, Program of Human Movement and Sport Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Marino Pereira Benetti
- Department of Biodynamics of Human Movements, School of Physical Education and Sports, University of São Paulo, São Paulo, Brazil
| | - Maria Augusta Pedanti Kiss
- Department of Biodynamics of Human Movements, School of Physical Education and Sports, University of São Paulo, São Paulo, Brazil
| | - Carlos Anibal Sierra
- Sports Cardiology Department, Dante Pazzanese Institute of Cardiology, São Paulo, Brazil
| | - Nabil Ghorayeb
- Sports Cardiology Department, Dante Pazzanese Institute of Cardiology, São Paulo, Brazil
| | - Jane T Seto
- Neuromuscular Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - João Bosco Pesquero
- Department of Biophysics, Federal University of São Paulo, São Paulo, Brazil
| | - Maria Fernanda Cury-Boaventura
- Department of Interdisciplinary in Health Sciences, Institute of Physical Activity and Sports Sciences, Cruzeiro do Sul University, São Paulo, Brazil
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7
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Strewe C, Zeller R, Feuerecker M, Hoerl M, Matzel S, Kumprej I, Crispin A, Johannes B, Debevec T, Mekjavic IB, Eiken O, Thiel M, Schelling G, Choukèr A. PlanHab Study: Consequences of combined normobaric hypoxia and bed rest on adenosine kinetics. Sci Rep 2018; 8:1762. [PMID: 29379127 PMCID: PMC5788919 DOI: 10.1038/s41598-018-20045-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 12/20/2017] [Indexed: 12/24/2022] Open
Abstract
Adenosine plays a role in the energy supply of cells and provokes differential, hormone-like functions in circulating cells and various tissues. Its release is importantly regulated by oxygen tension. This renders adenosine and its kinetics interesting to investigate in humans subjected to low oxygen conditions. Especially for space exploration scenarios, hypoxic conditions - together with reduced gravity - represent two foreseen living conditions when planning manned long-duration space missions or planetary habitats. The PlanHab study investigated microgravity through inactivity in bed rest and normobaric hypoxia to examine their independent or combined effect on adenosine and its kinetics. Healthy male subjects (n = 14) completed three 21-day interventions: hypoxic bed rest (HBR); hypoxic ambulatory confinement (HAMB); normoxic bed rest (NBR). The interventions were separated by 4 months. Our hypothesis of a hypoxia-triggered increase in adenosine was confirmed in HAMB but unexpectedly also in NBR. However, the highest adenosine levels were noted following HBR. Furthermore, the percentage of hemolysis was elevated in HBR whereas endothelial integrity markers stayed low in all three interventions. In summary, these data suggest that neocytolysis accounts for these effects while we could reduce evidence for microcirculatory changes.
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Affiliation(s)
- C Strewe
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany
| | - R Zeller
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany
| | - M Feuerecker
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany
| | - M Hoerl
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany
| | - S Matzel
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany
| | - I Kumprej
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany.,Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia
| | - A Crispin
- Institute for Medical Information Processing, Biometry and Epidemiology, Klinikum Großhadern, University of Munich, Munich, Germany
| | - B Johannes
- Division of Space Physiology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
| | - T Debevec
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - I B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - O Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
| | - M Thiel
- Department of Anaesthesiology and Surgical Intensive Care Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - G Schelling
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany
| | - A Choukèr
- Department of Anaesthesiology, University Hospital, LMU Munich, Laboratory of Translational Research "Stress and Immunity", Munich, Germany.
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8
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Grygorczyk R, Orlov SN. Effects of Hypoxia on Erythrocyte Membrane Properties-Implications for Intravascular Hemolysis and Purinergic Control of Blood Flow. Front Physiol 2017; 8:1110. [PMID: 29312010 PMCID: PMC5744585 DOI: 10.3389/fphys.2017.01110] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/14/2017] [Indexed: 01/08/2023] Open
Abstract
Intravascular hemolysis occurs in hereditary, acquired, and iatrogenic hemolytic conditions but it could be also a normal physiological process contributing to intercellular signaling. New evidence suggests that intravascular hemolysis and the associated release of adenosine triphosphate (ATP) may be an important mechanism for in vivo local purinergic signaling and blood flow regulation during exercise and hypoxia. However, the mechanisms that modulate hypoxia-induced RBC membrane fragility remain unclear. Here, we provide an overview of the role of RBC ATP release in the regulation of vascular tone and prevailing assumptions on the putative release mechanisms. We show importance of intravascular hemolysis as a source of ATP for local purinergic regulation of blood flow and discuss processes that regulate membrane propensity to rupture under stress and hypoxia.
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Affiliation(s)
| | - Sergei N. Orlov
- Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
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Makhro A, Haider T, Wang J, Bogdanov N, Steffen P, Wagner C, Meyer T, Gassmann M, Hecksteden A, Kaestner L, Bogdanova A. Comparing the impact of an acute exercise bout on plasma amino acid composition, intraerythrocytic Ca(2+) handling, and red cell function in athletes and untrained subjects. Cell Calcium 2016; 60:235-44. [PMID: 27292137 DOI: 10.1016/j.ceca.2016.05.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/20/2016] [Accepted: 05/19/2016] [Indexed: 12/30/2022]
Abstract
The N-methyl d-aspartate receptors (NMDARs) mediating Ca(2+) uptake upon stimulation with glutamate and glycine were recently discovered in red blood cells (RBC) of healthy humans. Activation of these receptors with agonists triggered transient Ca(2+)-dependent decrease in hemoglobin oxygen affinity in RBC suspension. The aim of this study was to assess the potential physiological relevance of this phenomenon. Two groups formed by either healthy untrained volunteers or endurance athletes were subjected to a stepwise incremental cycling test to exhaustion. Plasma glutamate levels, activity of the NMDARs, and hemoglobin O2 affinity were measured in blood samples obtained before and after the exercise in both groups. Increase in plasma glutamate levels following exercise was observed in both groups. Transient Ca(2+) accumulation in response to the NMDAR stimulation with NMDA and glycine was followed by facilitated Ca(2+) extrusion from the RBC and compensatory decrease in cytosolic Ca(2+) levels. Short-term activation of the receptors triggered a transient decrease in O2 affinity of hemoglobin in both groups. These exercise-induced responses were more pronounced in athletes compared to the untrained subjects. Athletes were initially presented with lower basal intracellular Ca(2+) levels and hemoglobin oxygen affinity compared to non-trained controls. High basal plasma glutamate levels were associated with induction of hemolysis and formation of echinocytes upon stimulation with the receptor agonists. These findings suggest that glutamate release occurring during exhaustive exercise bouts may acutely facilitate O2 liberation from hemoglobin and improve oxygen delivery to the exercising muscle.
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Affiliation(s)
- Asya Makhro
- Institute of Veterinary Physiology and the Zurich Center for Integrative Human Physiology (ZIHP), Zurich, Switzerland
| | - Thomas Haider
- Institute of Veterinary Physiology and the Zurich Center for Integrative Human Physiology (ZIHP), Zurich, Switzerland
| | - Jue Wang
- Institute for Molecular Cell Biology and Research Center for molecular Imaging and Screening, School of Medicine, Saarland University, Homburg, Germany
| | - Nikolay Bogdanov
- Institute of Veterinary Physiology and the Zurich Center for Integrative Human Physiology (ZIHP), Zurich, Switzerland
| | - Patrick Steffen
- Experimental Physics, Saarland University, Saarbrücken, Germany
| | | | - Tim Meyer
- Institute of Sports and Preventive Medicine, Saarland University, Saarbrücken, Germany
| | - Max Gassmann
- Institute of Veterinary Physiology and the Zurich Center for Integrative Human Physiology (ZIHP), Zurich, Switzerland
| | - Anne Hecksteden
- Institute of Sports and Preventive Medicine, Saarland University, Saarbrücken, Germany
| | - Lars Kaestner
- Institute for Molecular Cell Biology and Research Center for molecular Imaging and Screening, School of Medicine, Saarland University, Homburg, Germany; Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Anna Bogdanova
- Institute of Veterinary Physiology and the Zurich Center for Integrative Human Physiology (ZIHP), Zurich, Switzerland.
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10
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Burnstock G. Blood cells: an historical account of the roles of purinergic signalling. Purinergic Signal 2015; 11:411-34. [PMID: 26260710 PMCID: PMC4648797 DOI: 10.1007/s11302-015-9462-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 07/23/2015] [Indexed: 12/17/2022] Open
Abstract
The involvement of purinergic signalling in the physiology of erythrocytes, platelets and leukocytes was recognised early. The release of ATP and the expression of purinoceptors and ectonucleotidases on erythrocytes in health and disease are reviewed. The release of ATP and ADP from platelets and the expression and roles of P1, P2Y(1), P2Y(12) and P2X1 receptors on platelets are described. P2Y(1) and P2X(1) receptors mediate changes in platelet shape, while P2Y(12) receptors mediate platelet aggregation. The changes in the role of purinergic signalling in a variety of disease conditions are considered. The successful use of P2Y(12) receptor antagonists, such as clopidogrel and ticagrelor, for the treatment of thrombosis, myocardial infarction and stroke is discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK.
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Australia.
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11
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Abstract
The hypothesis that regulated ATP release from red blood cells (RBCs) contributes to nitric oxide-dependent control of local blood flow has sparked much interest in underlying release mechanisms. Several stimuli, including shear stress and hypoxia, have been found to induce significant RBC ATP release attributed to activation of ATP-conducting channels. In the present study, we first evaluated different experimental approaches investigating stimulated RBC ATP release and quantifying hemolysis. We then measured ATP and free hemoglobin in each and every RBC supernatant sample to directly assess the contribution of hemolysis to ATP release. Hypotonic shock, shear stress, and hypoxia, but not cyclic adenosine monophosphate agonists, significantly enhanced ATP release. It tightly correlated, however, with free hemoglobin in RBC supernatants, indicating that lysis was responsible for most, if not all, ATP release. Luminescence ATP imaging combined with simultaneous infrared cell imaging showed that ATP was released exclusively from lysing cells with no contribution from intact cells. In summary, with all stimuli tested, we found no evidence of regulated ATP release from intact RBCs other than by cell lysis. Such a release mechanism might be physiologically relevant in vivo, eg, during exercise and hypoxia where intravascular hemolysis, predominantly of senescent cells, is augmented.
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12
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Mairbäurl H. Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells. Front Physiol 2013; 4:332. [PMID: 24273518 PMCID: PMC3824146 DOI: 10.3389/fphys.2013.00332] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/25/2013] [Indexed: 11/24/2022] Open
Abstract
During exercise the cardiovascular system has to warrant substrate supply to working muscle. The main function of red blood cells in exercise is the transport of O2 from the lungs to the tissues and the delivery of metabolically produced CO2 to the lungs for expiration. Hemoglobin also contributes to the blood's buffering capacity, and ATP and NO release from red blood cells contributes to vasodilation and improved blood flow to working muscle. These functions require adequate amounts of red blood cells in circulation. Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called “sports anemia.” This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals. The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV). The mechanisms that increase total red blood cell mass by training are not understood fully. Despite stimulated erythropoiesis, exercise can decrease the red blood cell mass by intravascular hemolysis mainly of senescent red blood cells, which is caused by mechanical rupture when red blood cells pass through capillaries in contracting muscles, and by compression of red cells e.g., in foot soles during running or in hand palms in weightlifters. Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes. These younger red cells are characterized by improved oxygen release and deformability, both of which also improve tissue oxygen supply during exercise.
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Affiliation(s)
- Heimo Mairbäurl
- Medical Clinic VII, Sports Medicine, University of Heidelberg Heidelberg, Germany
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