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Role of Distinct Fat Depots in Metabolic Regulation and Pathological Implications. Rev Physiol Biochem Pharmacol 2022; 186:135-176. [PMID: 35915363 DOI: 10.1007/112_2022_73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
People suffering from obesity and associated metabolic disorders including diabetes are increasing exponentially around the world. Adipose tissue (AT) distribution and alteration in their biochemical properties play a major role in the pathogenesis of these diseases. Emerging evidence suggests that AT heterogeneity and depot-specific physiological changes are vital in the development of insulin resistance in peripheral tissues like muscle and liver. Classically, AT depots are classified into white adipose tissue (WAT) and brown adipose tissue (BAT); WAT is the site of fatty acid storage, while BAT is a dedicated organ of metabolic heat production. The discovery of beige adipocyte clusters in WAT depots indicates AT heterogeneity has a more central role than hither to ascribed. Therefore, we have discussed in detail the current state of understanding on cellular and molecular origin of different AT depots and their relevance toward physiological metabolic homeostasis. A major focus is to highlight the correlation between altered WAT distribution in the body and metabolic pathogenesis in animal models and humans. We have also underscored the disparity in the molecular (including signaling) changes in various WAT tissues during diabetic pathogenesis. Exercise-mediated beneficial alteration in WAT physiology/distribution that protects against metabolic disorders is evolving. Here we have discussed the depot-specific biochemical adjustments induced by different forms of exercise. A detailed understanding of the molecular details of inter-organ crosstalk via substrate utilization/storage and signaling through chemokines provide strategies to target selected WAT depots to pharmacologically mimic the benefits of exercise countering metabolic diseases including diabetes.
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Kocahan S, Dundar A, Onderci M, Yilmaz Y. Investigation of the effect of training on serotonin, melatonin and hematologic parameters in adolescent basketball players. Horm Mol Biol Clin Investig 2021; 42:383-388. [PMID: 34090322 DOI: 10.1515/hmbci-2020-0095] [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: 12/18/2020] [Accepted: 05/08/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Exercise can improve both health and mood. Some beneficial effects of exercise are attributed to endocrine status. This study aims to evaluate the effect of eight weeks of basketball training on melatonin, serotonin, and hematologic parameters in basketball players. METHODS The experimental group was selected form 34 healthy young boys, aged between 13 and 16 years old. The participants were randomly assigned to the control group (n=17) and the exercise group (n=17). The exercise program consisted of 2 h/day aerobic activity of basketball training in 5 days a week for 8 weeks. Venous blood was taken on the day before experiment (pre-exercise) and on the day following the last exercise (post-exercise) and hormone levels were detected by ELISA. RESULTS Serotonin and melatonin levels significantly increased in the post-exercise group compared to the other groups (p<0.05). Exercise caused increase in WBC, RBC, HCT and Hb levels (p<0.05) while did not alter PLT, MCH, and PCT levels (p>0.05). This study indicates that an eight weeks-long regular aerobic exercise increased melatonin and serotonin levels, and also altered some hematological parameters. CONCLUSIONS In conclusion, it is believed that improvement in levels of serotonin, melatonin, and hematological parameters after eight weeks of regular basketball training in basketball players could be attributed to beneficial effects of exercise. Investigation in other branches of sports and in different gender and age groups would make contribution into exercise physiology and training science.
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Affiliation(s)
- Sayad Kocahan
- Department of Physiology, Faculty of Medicine, University of Adiyaman, Adiyaman, Turkey.,International Scientific Center, Baku State University, Baku, Azerbaijan
| | - Aykut Dundar
- High School of Physical Education and Sports, University of Adiyaman, Adiyaman, Turkey
| | - Muhittin Onderci
- Department of Biochemistry, Faculty of Medicine, University of Adiyaman, Adiyaman, Turkey
| | - Yucehan Yilmaz
- Department of Physiology, Faculty of Medicine, University of Adiyaman, Adiyaman, Turkey
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The effects of normoxic endurance exercise on erythropoietin (EPO) production and the impact of selective β 1 and non-selective β 1 + β 2 adrenergic receptor blockade. Eur J Appl Physiol 2021; 121:1499-1511. [PMID: 33646423 DOI: 10.1007/s00421-020-04558-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 11/09/2020] [Indexed: 10/22/2022]
Abstract
PURPOSE Habitual endurance exercise results in increased erythropoiesis, which is primarily controlled by erythropoietin (EPO), yet studies demonstrating upregulation of EPO via a single bout of endurance exercise have been equivocal. This study compares the acute EPO response to 30 min of high versus 90 min of moderate-intensity endurance exercise and whether that response can be upregulated via selective adrenergic receptor blockade. METHODS Using a counterbalanced, cross-over design, fifteen participants (age 28 ± 8) completed two bouts of running (30-min, high intensity vs 90-min, moderate intensity) matched for overall training stress. A separate cohort of fourteen participants (age 31 ± 6) completed three bouts of 30-min high-intensity cycling after ingesting the preferential β1-adrenergic receptor (AR) antagonist bisoprolol, the non-preferential β1 + β2 antagonist nadolol or placebo. Venous blood was collected before, during, and after exercise, and serum EPO levels were determined by ELISA. RESULTS No detectable EPO response was observed during or after high intensity running, however, in the moderate-intensity trial EPO was significantly elevated at both during-exercise timepoints (+ 6.8% ± 2.3% at 15 min and + 8.7% ± 2.2% at 60 min). No significant change in EPO was observed post-cycling or between the trials involving βAR blockade. CONCLUSION Neither training mode (running or cycling), nor beta-blockade significantly influenced the EPO response to 30 min of high-intensity exercise, however, 90 min of moderate-intensity running elevated EPO during exercise, returning to baseline immediately post-exercise. Identifying the optimal mode, duration and intensity required to evoke an EPO response to exercise may help tailor exercise prescriptions designed to maximize EPO response for both performance and clinical applications.
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Lundby C, Montero D, Joyner M. Biology of VO 2 max: looking under the physiology lamp. Acta Physiol (Oxf) 2017; 220:218-228. [PMID: 27888580 DOI: 10.1111/apha.12827] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 08/26/2016] [Accepted: 10/28/2016] [Indexed: 12/20/2022]
Abstract
In this review, we argue that several key features of maximal oxygen uptake (VO2 max) should underpin discussions about the biological and reductionist determinants of its interindividual variability: (i) training-induced increases in VO2 max are largely facilitated by expansion of red blood cell volume and an associated improvement in stroke volume, which also adapts independent of changes in red blood cell volume. These general concepts are also informed by cross-sectional studies in athletes that have very high values for VO2 max. Therefore, (ii) variations in VO2 max improvements with exercise training are also likely related to variations in these physiological determinants. (iii) All previously untrained individuals will respond to endurance exercise training in terms of improvements in VO2 max provided the stimulus exceeds a certain volume and/or intensity. Thus, genetic analysis and/or reductionist studies performed to understand or predict such variations might focus specifically on DNA variants or other molecular phenomena of relevance to these physiological pathways.
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Affiliation(s)
- C. Lundby
- Zürich Center for Integrative Human Physiology; Institute of Physiology; University of Zürich; Zürich Switzerland
| | - D. Montero
- Department of Cardiology; University Hospital Zürich; Zürich Switzerland
| | - M. Joyner
- Department of Anesthesiology; Mayo Clinic; Rochester MN USA
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Montero D, Breenfeldt-Andersen A, Oberholzer L, Haider T, Goetze JP, Meinild-Lundby AK, Lundby C. Erythropoiesis with endurance training: dynamics and mechanisms. Am J Physiol Regul Integr Comp Physiol 2017; 312:R894-R902. [DOI: 10.1152/ajpregu.00012.2017] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/06/2017] [Accepted: 03/31/2017] [Indexed: 11/22/2022]
Abstract
The purpose of the present study was to characterize the progression of red blood cell volume (RBCV) expansion and potential volumetric and endocrine regulators of erythropoiesis during endurance training (ET). Nine healthy, untrained volunteers (age = 27 ± 4 yr) underwent supervised ET consisting of 3–4 × 60 min cycle ergometry sessions per week for 8 wk. Plasma volume (PV), RBCV, and overnight fasting hematological markers were determined before and at weeks 2, 4, and 8 of ET. In addition, plasma erythropoietin (EPO), cortisol, copeptin, and proatrial natriuretic peptide concentrations were measured during a 3-h morning period at baseline and postexercise at weeks 1 and 8. PV increased from baseline (2,405 ± 335 ml) at weeks 2, 4, and 8 (+374 ± 194, +505 ± 156, and +341 ± 160 ml, respectively, P < 0.001). Increases in RBCV from baseline (1,737 ± 442 ml) were manifested at week 4 (+109 ± 114 ml, P = 0.030) and week 8 (+205 ± 109 ml, P = 0.001). Overnight fasting plasma EPO concentration increased from baseline (11.3 ± 4.8 mIU/ml) at week 2 (+2.5 ± 2.8 mIU·ml−1, P = 0.027) and returned to baseline concentration at weeks 4 and 8. Higher 3-h-postexercise EPO concentration was observed at week 1 (11.6 mIU/ml) compared with week 8 (8.4 ± 3.9 mIU/ml, P = 0.009) and baseline (9.0 ± 4.2 mIU/ml, P = 0.019). Linear relationships between EPO concentration and hematocrit (β = −56.2, P < 0.001) and cortisol (β = 0.037, P < 0.001) were detected throughout the ET intervention. In conclusion, ET leads to mild, transient increases in circulating EPO concentration, concurring with early PV expansion and lowered hematocrit, preceding gradual RBCV enhancement.
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Affiliation(s)
- David Montero
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland
- Department of Cardiology, University Hospital Zurich, Zurich, Switzerland
| | - Andreas Breenfeldt-Andersen
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark; and
| | - Laura Oberholzer
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas Haider
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Jens P. Goetze
- Department of Clinical Biochemistry, Copenhagen, and Aarhus University, Aarhus, Denmark
| | - Anne-Kristine Meinild-Lundby
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Carsten Lundby
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland
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Brocherie F, Millet GP, Hauser A, Steiner T, Wehrlin JP, Rysman J, Girard O. Association of Hematological Variables with Team-Sport Specific Fitness Performance. PLoS One 2015; 10:e0144446. [PMID: 26641647 PMCID: PMC4671600 DOI: 10.1371/journal.pone.0144446] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 11/18/2015] [Indexed: 11/21/2022] Open
Abstract
Purpose We investigated association of hematological variables with specific fitness performance in elite team-sport players. Methods Hemoglobin mass (Hbmass) was measured in 25 elite field hockey players using the optimized (2 min) CO-rebreathing method. Hemoglobin concentration ([Hb]), hematocrit and mean corpuscular hemoglobin concentration (MCHC) were analyzed in venous blood. Fitness performance evaluation included a repeated-sprint ability (RSA) test (8 x 20 m sprints, 20 s of rest) and the Yo-Yo intermittent recovery level 2 (YYIR2). Results Hbmass was largely correlated (r = 0.62, P<0.01) with YYIR2 total distance covered (YYIR2TD) but not with any RSA-derived parameters (r ranging from -0.06 to -0.32; all P>0.05). [Hb] and MCHC displayed moderate correlations with both YYIR2TD (r = 0.44 and 0.41; both P<0.01) and RSA sprint decrement score (r = -0.41 and -0.44; both P<0.05). YYIR2TD correlated with RSA best and total sprint times (r = -0.46, P<0.05 and -0.60, P<0.01; respectively), but not with RSA sprint decrement score (r = -0.19, P>0.05). Conclusion Hbmass is positively correlated with specific aerobic fitness, but not with RSA, in elite team-sport players. Additionally, the negative relationships between YYIR2 and RSA tests performance imply that different hematological mechanisms may be at play. Overall, these results indicate that these two fitness tests should not be used interchangeably as they reflect different hematological mechanisms.
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Affiliation(s)
- Franck Brocherie
- ISSUL, Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- * E-mail:
| | - Grégoire P. Millet
- ISSUL, Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Anna Hauser
- ISSUL, Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Swiss Federal Institute of Sport, Section for Elite Sport, Magglingen, Switzerland
| | - Thomas Steiner
- Swiss Federal Institute of Sport, Section for Elite Sport, Magglingen, Switzerland
| | - Jon P. Wehrlin
- Swiss Federal Institute of Sport, Section for Elite Sport, Magglingen, Switzerland
| | - Julien Rysman
- Faculty of Motor Sciences, Université Libre de Bruxelles, Brussels, Belgium
| | - Olivier Girard
- ISSUL, Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- ASPETAR, Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar
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Montero D, Cathomen A, Jacobs RA, Flück D, de Leur J, Keiser S, Bonne T, Kirk N, Lundby AK, Lundby C. Haematological rather than skeletal muscle adaptations contribute to the increase in peak oxygen uptake induced by moderate endurance training. J Physiol 2015; 593:4677-88. [PMID: 26282186 DOI: 10.1113/jp270250] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 08/04/2015] [Indexed: 12/26/2022] Open
Abstract
It remains unclear whether improvements in peak oxygen uptake (V̇(O2peak)) following endurance training (ET) are primarily determined by central and/or peripheral adaptations. Herein, we tested the hypothesis that the improvement in V̇(O2peak) following 6 weeks of ET is mainly determined by haematological rather than skeletal muscle adaptations. Sixteen untrained healthy male volunteers (age = 25 ± 4 years, V̇(O2peak) = 3.5 ± 0.5 l min(-1)) underwent supervised ET (6 weeks, 3-4 sessions per week). V̇(O2peak), peak cardiac output (Q̇(peak)), haemoglobin mass (Hb(mass)) and blood volumes were assessed prior to and following ET. Skeletal muscle biopsies were analysed for mitochondrial volume density (Mito(VD)), capillarity, fibre types and respiratory capacity (OXPHOS). After the post-ET assessment, red blood cell volume (RBCV) was re-established at the pre-ET level by phlebotomy and V̇(O2peak) and Q̇(peak) were measured again. We speculated that the contribution of skeletal muscle adaptations to the ET-induced increase in V̇(O2peak) would be revealed when controlling for haematological adaptations. V̇(O2peak) and Q̇(peak) were increased (P < 0.05) following ET (9 ± 8 and 7 ± 6%, respectively) and decreased (P < 0.05) after phlebotomy (-7 ± 7 and -10 ± 7%). RBCV, plasma volume and Hb(mass) all increased (P < 0.05) after ET (8 ± 4, 4 ± 6 and 6 ± 5%). As for skeletal muscle adaptations, capillary-to-fibre ratio and total Mito(VD) increased (P < 0.05) following ET (18 ± 16 and 43 ± 30%), but OXPHOS remained unaltered. Through stepwise multiple regression analysis, Q̇(peak), RBCV and Hb(mass) were found to be independent predictors of V̇(O2peak). In conclusion, the improvement in V̇(O2peak) following 6 weeks of ET is primarily attributed to increases in Q̇(peak) and oxygen-carrying capacity of blood in untrained healthy young subjects.
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Affiliation(s)
- David Montero
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
| | - Adrian Cathomen
- Institute of Human Movement Sciences and Sport, ETH Zurich, Switzerland
| | - Robert A Jacobs
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland.,Health and Physical Education, School of Teaching and Learning, Western Carolina University, Cullowhee, NC, USA
| | - Daniela Flück
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
| | - Jeroen de Leur
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
| | - Stefanie Keiser
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
| | - Thomas Bonne
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
| | - Niels Kirk
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
| | - Anne-Kristine Lundby
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
| | - Carsten Lundby
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Institute of Physiology, Switzerland
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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: 210] [Impact Index Per Article: 19.1] [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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Hu M, Lin W. Effects of exercise training on red blood cell production: implications for anemia. Acta Haematol 2012; 127:156-64. [PMID: 22301865 DOI: 10.1159/000335620] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 11/29/2011] [Indexed: 12/24/2022]
Abstract
Exercise training can increase total Hb and red cell mass, which enhances oxygen-carrying capacity. The possible underlying mechanisms are proposed to come mainly from bone marrow, including stimulated erythropoiesis with hyperplasia of the hematopoietic bone marrow, improvement of the hematopoietic microenvironment induced by exercise training, and hormone- and cytokine-accelerated erythropoiesis. Anemia is one of the most common medical conditions in chronic disease. The effects of exercise training on counteracting anemia have been explored and evaluated. The results of the research available to date are controversial, and it seems that significant methodological limitations exist. However, exercise training might be a promising, additional, safe and economical method to help improve anemia. There is a need for further investigation into the effects of and guidelines for exercise interventions (especially strength training) in this population of patients, particularly among cancer patients who are undergoing or have undergone chemotherapy or radiation treatments. As the available data are limited, additional research to uncover the underlying mechanisms associated with the effects of exercise training on anemia is clearly warranted.
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Affiliation(s)
- Min Hu
- Laboratory Center for Sport Science and Medicine, Guangzhou Institute of Physical Education, China.
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Effects of high altitude and exercise on plasma erythropoietin in equids. COMPARATIVE EXERCISE PHYSIOLOGY 2011. [DOI: 10.1017/s1755254011000109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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A definition of normovolaemia and consequences for cardiovascular control during orthostatic and environmental stress. Eur J Appl Physiol 2010; 109:141-57. [PMID: 20052592 PMCID: PMC2861179 DOI: 10.1007/s00421-009-1346-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2009] [Indexed: 11/20/2022]
Abstract
The Frank–Starling mechanism describes the relationship between stroke volume and preload to the heart, or the volume of blood that is available to the heart—the central blood volume. Understanding the role of the central blood volume for cardiovascular control has been complicated by the fact that a given central blood volume may be associated with markedly different central vascular pressures. The central blood volume varies with posture and, consequently, stroke volume and cardiac output (\documentclass[12pt]{minimal}
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\begin{document}$$ \dot{Q} $$\end{document}) are affected, but with the increased central blood volume during head-down tilt, stroke volume and \documentclass[12pt]{minimal}
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\begin{document}$$ \dot{Q} $$\end{document} do not increase further indicating that in the supine resting position the heart operates on the plateau of the Frank–Starling curve which, therefore, may be taken as a functional definition of normovolaemia. Since the capacity of the vascular system surpasses the blood volume, orthostatic and environmental stress including bed rest/microgravity, exercise and training, thermal loading, illness, and trauma/haemorrhage is likely to restrict venous return and \documentclass[12pt]{minimal}
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\begin{document}$$ \dot{Q} $$\end{document}. Consequently the cardiovascular responses are determined primarily by their effect on the central blood volume. Thus during environmental stress, flow redistribution becomes dependent on sympathetic activation affecting not only skin and splanchnic blood flow, but also flow to skeletal muscles and the brain. This review addresses the hypothesis that deviations from normovolaemia significantly influence these cardiovascular responses.
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Consitt LA, Wideman L, Hickey MS, Morrison RF. Phosphorylation of the JAK2-STAT5 pathway in response to acute aerobic exercise. Med Sci Sports Exerc 2008; 40:1031-8. [PMID: 18461004 DOI: 10.1249/mss.0b013e3181690760] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
UNLABELLED Growth hormone (GH) is a powerful stimulator of the Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5) pathway. Acute exercise is a known stimulus for GH secretion. PURPOSE The purpose of this study was to determine the phosphorylation of the JAK2-STAT5 pathway in human skeletal muscle in response to acute aerobic exercise. METHODS Eleven young (22.5 +/- 0.6, mean +/- SE), healthy, aerobically trained males performed 30 min of cycling at 70% V O2max. Blood samples were collected at 10- to 15-min intervals and analyzed for human GH, immunofunctional (IF) GH, GH binding protein, and insulin-like growth factor I (IGF-I). Muscle biopsies were taken from the vastus lateralis before exercise, immediately after exercise, as well as, 30 and 60 min postexercise. Muscle samples were analyzed for changes in JAK2 and STAT5 tyrosine phosphorylation, as well as changes in JAK2 and STAT5 protein content. RESULTS Multivariate ANOVA with post hoc comparisons demonstrated that GH and IF GH were significantly elevated immediately after exercise compared with preexercise (P < 0.001). Exercise significantly increased the phosphorylation of JAK2 immediately after exercise (P = 0.004). A trend toward increasing levels of STAT5 phosphorylation was observed immediately after exercise (P = 0.08) and was significantly elevated 30 min after exercise (P = 0.002), compared with preexercise levels. Muscle JAK2 and STAT5 protein content did not change. CONCLUSION The results demonstrate that the JAK2-STAT5 pathway is activated in response to acute aerobic exercise in human skeletal muscle and suggests that the exercise-induced release of GH may play a role in the activation of this pathway.
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Affiliation(s)
- Leslie A Consitt
- Department of Exercise and Sport Science, University of North Carolina at Greensboro, Greensboro, NC 27858, USA.
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Vogt S, Altehoefer C, Bueltermann D, Pottgiesser T, Prettin S, Schmid A, Roecker K, Schmidt W, Heinicke K, Heinrich L. Magnetic resonance imaging of the lumbar spine and blood volume in professional cyclists. Eur J Appl Physiol 2007; 102:411-6. [DOI: 10.1007/s00421-007-0599-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 10/15/2007] [Indexed: 10/22/2022]
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Bonsignore MR, Morici G, Santoro A, Pagano M, Cascio L, Bonanno A, Abate P, Mirabella F, Profita M, Insalaco G, Gioia M, Vignola AM, Majolino I, Testa U, Hogg JC. Circulating hematopoietic progenitor cells in runners. J Appl Physiol (1985) 2002; 93:1691-7. [PMID: 12381755 DOI: 10.1152/japplphysiol.00376.2002] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Because endurance exercise causes release of mediators and growth factors active on the bone marrow, we asked whether it might affect circulating hematopoietic progenitor cells (HPCs) in amateur runners [n = 16, age: 41.8 +/- 13.5 (SD) yr, training: 93.8 +/- 31.8 km/wk] compared with sedentary controls (n = 9, age: 39.4 +/- 10.2 yr). HPCs, plasma cortisol, interleukin (IL)-6, granulocyte colony-stimulating factor (G-CSF), and the growth factor fms-like tyrosine kinase-3 (flt3)-ligand were measured at rest and after a marathon (M; n = 8) or half-marathon (HM; n = 8). Circulating HPC counts (i.e., CD34(+) cells and their subpopulations) were three- to fourfold higher in runners than in controls at baseline. They were unaffected by HM or M acutely but decreased the morning postrace. Baseline cortisol, flt3-ligand, IL-6, and G-CSF levels were similar in runners and controls. IL-6 and G-CSF increased to higher levels after M compared with HM, whereas cortisol and flt3-ligand increased similarly postrace. Our data suggest that increased HPCs reflect an adaptation response to recurrent, exercise-associated release of neutrophils and stress and inflammatory mediators, indicating modulation of bone marrow activity by habitual running.
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Affiliation(s)
- Maria R Bonsignore
- Institute of Respiratory Pathophysiology, National Research Council, 90146 Palermo, Italy.
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16
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Abstract
Fine-tuning of the response to exercise that lasts longer than a few seconds is reliant on the regulation of several key variables governing the cardiopulmonary, vascular, and metabolic response to exercise. This type of integrative response requires communication between organ systems that relies on the secretion of endocrine and paracrine substances by one tissue or organ that are transported remotely to other tissues or organs to evoke a response to adjust to the disturbance.
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Affiliation(s)
- Kenneth Harrington McKeever
- Department of Animal Science, Cook College, Rutgers--The State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA.
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17
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Lounana J, Matsin T, Menuet J, Boitte F, Maillet M, Medelli J. Effet d'un exercice maximal sur les concentrations plasmatiques d'érythropoı̈étine (EPO). Sci Sports 2002. [DOI: 10.1016/s0765-1597(02)00151-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Abstract
The use of DNA-recombinant human epoetin-alfa (rhEPO) as a pharmacological ergogenic aid for the enhancement of aerobic performance is estimated to be practised by at least 3 to 7% of elite endurance sport athletes. rhEPO is synthesised from Chinese hamster ovary cells, and is nearly identical biochemically and immunologically to endogenous epoetin-alfa (EPO). In a clinical setting, rhEPO is used to stimulate erythrocyte production in patients with end-stage renal disease and anaemia. A limited number of human studies have suggested that rhEPO provides a significant erythropoietic and ergogenic benefit in trained individuals as evidenced by increments in haemoglobin, haematocrit, maximal oxygen uptake (VO2max) and exercise endurance time. The purpose of this review is to summarise the various technologies and methodologies currently available for the detection of illicit use of rhEPO in athletes. The International Olympic Committee (IOC) banned the use of rhEPO as an ergogenic aid in 1990. Since then a number of methods have been proposed as potential techniques for detecting the illegal use of rhEPO. Most of these techniques use indirect markers to detect rhEPO in blood samples. These indirect markers include macrocytic hypochromatic erythrocytes and serum soluble transferrin receptor (sTfr) concentration. Another indirect technique uses a combination of 5 markers of enhanced erythropoiesis (haematocrit, reticulocyte haematocrit, percentage of macrocytic red blood cells, serum EPO, sTfr) to detect rhEPO. The electrophoretic mobility technique provides a direct measurement of urine and serum levels of rhEPO, and is based on the principle that the rhEPO molecule is less negatively charged versus the endogenous EPO molecule. Isoelectric patterning/focusing has emerged recently as a potential method for the direct analysis of rhEPO in urine. Among these various methodologies, the indirect technique that utilises multiple markers of enhanced erythropoiesis appears to be the most valid, reliable and feasible protocol currently available for the detection of rhEPO in athletes. In August 2000, the IOC Medical Commission approved this protocol known as the 'ON model', and it was subsequently used in combination with a second, confirmatory test (isoelectric patterning) to detect rhEPO abusers competing in the 2000 Sydney Summer Olympics. This combined blood and urine test was approved with modifications by the IOC in November 2001 for use in the 2002 Salt Lake City Winter Olympics.
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Affiliation(s)
- Randall L Wilber
- Sport Science and Technology Division, United States Olympic Committee, Colorado Springs, Colorado 80909, USA.
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19
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Breymann C. Erythropoietin test methods. BAILLIERE'S BEST PRACTICE & RESEARCH. CLINICAL ENDOCRINOLOGY & METABOLISM 2000; 14:135-45. [PMID: 10932816 DOI: 10.1053/beem.2000.0059] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recombinant human erythropoietin (rhEPO), which increases red cell mass, is one of the most abused substances in sport. Abuse is currently undetectable by the only direct routine method, immunoassay, since blood and urine rhEPO are immunologically indistinguishable from endogenous EPO. Elevated EPO levels are only detectable several days after rhEPO administration. Indirect parameters have therefore been introduced, primarily the haematocrit level, but also markers of functional iron deficiency during or after rhEPO administration (hypochromic red cells and reticulocytes, serum transferrin receptors, ferritin levels) and, in the urine, fibrin degradation products. Although iron status indices have yielded promising results, athletes are currently banned solely on the basis of their haematocrit. Yet various factors can cause false positive haematocrit results with potentially fatal consequences to athletes' careers. Until new direct assays such as liquid chromatography-mass spectrometry have been evaluated and introduced, efforts must be directed at using a battery of tests to increase the sensitivity and specificity and reduce the number of false positives and false negatives.
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Affiliation(s)
- C Breymann
- Department of Obstetrics and Gynaecology, University Hospital of Zurich, Switzerland
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