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Chatzinikolaou PN, Margaritelis NV, Paschalis V, Theodorou AA, Vrabas IS, Kyparos A, D'Alessandro A, Nikolaidis MG. Erythrocyte metabolism. Acta Physiol (Oxf) 2024; 240:e14081. [PMID: 38270467 DOI: 10.1111/apha.14081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/11/2023] [Accepted: 01/01/2024] [Indexed: 01/26/2024]
Abstract
Our aim is to present an updated overview of the erythrocyte metabolism highlighting its richness and complexity. We have manually collected and connected the available biochemical pathways and integrated them into a functional metabolic map. The focus of this map is on the main biochemical pathways consisting of glycolysis, the pentose phosphate pathway, redox metabolism, oxygen metabolism, purine/nucleoside metabolism, and membrane transport. Other recently emerging pathways are also curated, like the methionine salvage pathway, the glyoxalase system, carnitine metabolism, and the lands cycle, as well as remnants of the carboxylic acid metabolism. An additional goal of this review is to present the dynamics of erythrocyte metabolism, providing key numbers used to perform basic quantitative analyses. By synthesizing experimental and computational data, we conclude that glycolysis, pentose phosphate pathway, and redox metabolism are the foundations of erythrocyte metabolism. Additionally, the erythrocyte can sense oxygen levels and oxidative stress adjusting its mechanics, metabolism, and function. In conclusion, fine-tuning of erythrocyte metabolism controls one of the most important biological processes, that is, oxygen loading, transport, and delivery.
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Affiliation(s)
- Panagiotis N Chatzinikolaou
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Nikos V Margaritelis
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Vassilis Paschalis
- School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasios A Theodorou
- Department of Life Sciences, School of Sciences, European University Cyprus, Nicosia, Cyprus
| | - Ioannis S Vrabas
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Antonios Kyparos
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Angelo D'Alessandro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Michalis G Nikolaidis
- Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
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Hitosugi N, Hotta K, Taketa Y, Takamizawa R, Fujii Y, Ikegami R, Tamiya H, Inoue T, Tsubaki A. The effect of sepsis and reactive oxygen species on skeletal muscle interstitial oxygen pressure during contractions. Microcirculation 2024; 31:e12833. [PMID: 37800537 DOI: 10.1111/micc.12833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/09/2023] [Accepted: 09/23/2023] [Indexed: 10/07/2023]
Abstract
OBJECTIVE This study aims to examine the effect of sepsis on the dynamics of skeletal muscle partial oxygen pressure during muscle contractions as well as the effect of reactive oxygen species (ROS) scavenger (ascorbic acid, Asc). METHODS Twenty-seven male Sprague-Dawley rats (2-3 months old) were randomly assigned to three groups; sham, cecal ligation and puncture (CLP), or CLP plus ascorbic acid treatment group (CLP + Asc). Electrical stimuli-induced muscle contractions and partial oxygen pressure measurements were performed at 3 h after CLP. The interstitial oxygen pressure (PO2 is) in the spinotrapezius muscle was measured by the phosphorescence quenching method. RESULTS The PO2 is at rest was not different between the three groups. The PO2 is decreased from rest to contraction in all groups. Compared to the sham, the time to decrease PO2 is was significantly faster in CLP but not in CLP + Asc (p < .05). Compared to the sham, the PO2 is during muscle contractions was significantly lower in both CLP and CLP + Asc (p < .05, respectively). CONCLUSIONS Our results suggest that CLP-induced sepsis accelerated the decay of PO2 is at the onset of muscle contractions and maintained a low level of PO2 is during muscle contractions.
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Affiliation(s)
- Naoki Hitosugi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - Kazuki Hotta
- Department of Rehabilitation Sciences, Graduate School of Medical Sciences, Kitasato University, Sagamihara, Japan
- Department of Rehabilitation, Kitasato University School of Allied Health Sciences, Sagamihara, Japan
| | - Yoshikazu Taketa
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata, Japan
| | - Ren Takamizawa
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - Yutaka Fujii
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
- Department of Clinical Engineering and Medical Technology, Niigata University of Health and Welfare, Niigata, Japan
| | - Ryo Ikegami
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata, Japan
| | - Hajime Tamiya
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata, Japan
| | - Tatsuro Inoue
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata, Japan
| | - Atsuhiro Tsubaki
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata, Japan
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Betz MW, Hendriks FK, Houben AJ, van den Eynde MD, Verdijk LB, van Loon LJ, Snijders T. Type II Muscle Fiber Capillarization Is an Important Determinant of Post-Exercise Microvascular Perfusion in Older Adults. Gerontology 2023; 70:290-301. [PMID: 38109855 PMCID: PMC10911174 DOI: 10.1159/000535831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 12/12/2023] [Indexed: 12/20/2023] Open
Abstract
INTRODUCTION Microvascular perfusion is essential for post-exercise skeletal muscle recovery to ensure adequate delivery of nutrients and growth factors. This study assessed the relationship between various indices of muscle fiber capillarization and microvascular perfusion assessed by contrast-enhanced ultrasound (CEUS) at rest and during recovery from a bout of resistance exercise in older adults. METHODS Sixteen older adults (72 ± 6 y, 5/11 male/female) participated in an experimental test day during which a muscle biopsy was collected from the vastus lateralis and microvascular perfusion was determined by CEUS at rest and at 10 and 40 min following a bout of resistance exercise. Immunohistochemistry was performed on muscle tissue samples to determine various indices of both mixed and fiber-type-specific muscle fiber capillarization. RESULTS Microvascular blood volume at t = 10 min was higher compared with rest and t = 40 min (27.2 ± 4.7 vs. 3.9 ± 4.0 and 7.0 ± 4.9 AU, respectively, both p < 0.001). Microvascular blood volume at t = 40 min was higher compared with rest (p < 0.001). No associations were observed between different indices of mixed muscle fiber capillarization and microvascular blood volume at rest and following exercise. A moderate (r = 0.59, p < 0.05) and strong (r = 0.81, p < 0.001) correlation was observed between type II muscle fiber capillary-to-fiber ratio and the microvascular blood volume increase from rest to t = 10 and t = 40 min, respectively. In addition, type II muscle fiber capillary contacts and capillary-to-fiber perimeter exchange index were strongly correlated with the microvascular blood volume increase from rest to t = 40 min (r = 0.66, p < 0.01 and r = 0.64, p < 0.01, respectively). CONCLUSION Resistance exercise strongly increases microvascular blood volume for at least 40 min after exercise cessation in older adults. This resistance exercise-induced increase in microvascular blood volume is strongly associated with type II muscle fiber capillarization in older adults.
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Affiliation(s)
- Milan W. Betz
- Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Floris K. Hendriks
- Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Alfons J.H.M. Houben
- Department of Internal Medicine, School for Cardiovascular Diseases (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Mathias D.G. van den Eynde
- Department of Internal Medicine, School for Cardiovascular Diseases (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Lex B. Verdijk
- Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Luc J.C. van Loon
- Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Tim Snijders
- Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
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Sietsema KE, Rossiter HB. Exercise Physiology and Cardiopulmonary Exercise Testing. Semin Respir Crit Care Med 2023; 44:661-680. [PMID: 37429332 DOI: 10.1055/s-0043-1770362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
Aerobic, or endurance, exercise is an energy requiring process supported primarily by energy from oxidative adenosine triphosphate synthesis. The consumption of oxygen and production of carbon dioxide in muscle cells are dynamically linked to oxygen uptake (V̇O2) and carbon dioxide output (V̇CO2) at the lung by integrated functions of cardiovascular, pulmonary, hematologic, and neurohumoral systems. Maximum oxygen uptake (V̇O2max) is the standard expression of aerobic capacity and a predictor of outcomes in diverse populations. While commonly limited in young fit individuals by the capacity to deliver oxygen to exercising muscle, (V̇O2max) may become limited by impairment within any of the multiple systems supporting cellular or atmospheric gas exchange. In the range of available power outputs, endurance exercise can be partitioned into different intensity domains representing distinct metabolic profiles and tolerances for sustained activity. Estimates of both V̇O2max and the lactate threshold, which marks the upper limit of moderate-intensity exercise, can be determined from measures of gas exchange from respired breath during whole-body exercise. Cardiopulmonary exercise testing (CPET) includes measurement of V̇O2 and V̇CO2 along with heart rate and other variables reflecting cardiac and pulmonary responses to exercise. Clinical CPET is conducted for persons with known medical conditions to quantify impairment, contribute to prognostic assessments, and help discriminate among proximal causes of symptoms or limitations for an individual. CPET is also conducted in persons without known disease as part of the diagnostic evaluation of unexplained symptoms. Although CPET quantifies a limited sample of the complex functions and interactions underlying exercise performance, both its specific and global findings are uniquely valuable. Some specific findings can aid in individualized diagnosis and treatment decisions. At the same time, CPET provides a holistic summary of an individual's exercise function, including effects not only of the primary diagnosis, but also of secondary and coexisting conditions.
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Affiliation(s)
- Kathy E Sietsema
- Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, David Geffen School of Medicine at UCLA, Torrance, California
| | - Harry B Rossiter
- Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, David Geffen School of Medicine at UCLA, Torrance, California
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Mendelson AA, Erickson D, Villar R. The role of the microcirculation and integrative cardiovascular physiology in the pathogenesis of ICU-acquired weakness. Front Physiol 2023; 14:1170429. [PMID: 37234410 PMCID: PMC10206327 DOI: 10.3389/fphys.2023.1170429] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
Skeletal muscle dysfunction after critical illness, defined as ICU-acquired weakness (ICU-AW), is a complex and multifactorial syndrome that contributes significantly to long-term morbidity and reduced quality of life for ICU survivors and caregivers. Historically, research in this field has focused on pathological changes within the muscle itself, without much consideration for their in vivo physiological environment. Skeletal muscle has the widest range of oxygen metabolism of any organ, and regulation of oxygen supply with tissue demand is a fundamental requirement for locomotion and muscle function. During exercise, this process is exquisitely controlled and coordinated by the cardiovascular, respiratory, and autonomic systems, and also within the skeletal muscle microcirculation and mitochondria as the terminal site of oxygen exchange and utilization. This review highlights the potential contribution of the microcirculation and integrative cardiovascular physiology to the pathogenesis of ICU-AW. An overview of skeletal muscle microvascular structure and function is provided, as well as our understanding of microvascular dysfunction during the acute phase of critical illness; whether microvascular dysfunction persists after ICU discharge is currently not known. Molecular mechanisms that regulate crosstalk between endothelial cells and myocytes are discussed, including the role of the microcirculation in skeletal muscle atrophy, oxidative stress, and satellite cell biology. The concept of integrated control of oxygen delivery and utilization during exercise is introduced, with evidence of physiological dysfunction throughout the oxygen delivery pathway - from mouth to mitochondria - causing reduced exercise capacity in patients with chronic disease (e.g., heart failure, COPD). We suggest that objective and perceived weakness after critical illness represents a physiological failure of oxygen supply-demand matching - both globally throughout the body and locally within skeletal muscle. Lastly, we highlight the value of standardized cardiopulmonary exercise testing protocols for evaluating fitness in ICU survivors, and the application of near-infrared spectroscopy for directly measuring skeletal muscle oxygenation, representing potential advancements in ICU-AW research and rehabilitation.
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Affiliation(s)
- Asher A. Mendelson
- Section of Critical Care Medicine, Department of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Dustin Erickson
- Section of Critical Care Medicine, Department of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Rodrigo Villar
- Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB, Canada
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Martínez-Noguera FJ, Alcaraz PE, Carlos-Vivas J, Marín-Pagán C. 8 weeks of 2 S-hesperidin prevents a decrease in pO 2 at submaximal intensity in amateur cyclists in off-season: randomized controlled trial. Food Funct 2023; 14:2750-2767. [PMID: 36857626 DOI: 10.1039/d2fo03007a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although chronic supplementation with 2S-hesperidin has been shown to improve performance, to date, the possible mechanisms underlying this effect have not been explored. Therefore, the aim of this study was to assess whether changes in gasometry may be associated with improved performance after the intake of 2S-hesperidin (500 mg d-1, 8 weeks). Forty amateur cyclists (n = 20 2S-hesperidin, n = 20 placebo) performed a rectangular test, during which capillary blood samples were taken at the baseline, FatMax1, ventilatory threshold 1 and 2 (VT1 and VT2), power maximum (PMAX), FatMax2 and excess post-exercise O2 consumption (EPOC) to measure gasometry parameters. Significantly increased CO2 and tCO2 was found at FatMax1, VT1, FatMax2 and EPOC (p = <0.05) after 8 weeks of 2S-hesperidin ingestion. Conversely, the placebo group had a significant decrease in pO2 at VT2 (p = 0.04) during the rectangular test, with no changes in the 2S-hesperidin group. Therefore, chronic supplementation with 2S-hesperidin prevents decreases in pO2 at submaximal intensities in amateur cyclists in an off-season period.
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Affiliation(s)
- Francisco Javier Martínez-Noguera
- Research Center for High Performance Sport, Catholic University of Murcia, Campus de los Jerónimos N° 135, UCAM, 30107, Murcia, Spain.
| | - Pedro E Alcaraz
- Research Center for High Performance Sport, Catholic University of Murcia, Campus de los Jerónimos N° 135, UCAM, 30107, Murcia, Spain.
| | - Jorge Carlos-Vivas
- Health, Economy, Motricity and Education Research Group (HEME), Faculty of Sport Sciences, University of Extremadura, Avda. de Elvas, s/n., 06006, Badajoz, Spain.
| | - Cristian Marín-Pagán
- Research Center for High Performance Sport, Catholic University of Murcia, Campus de los Jerónimos N° 135, UCAM, 30107, Murcia, Spain.
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Interaction of Factors Determining Critical Power. Sports Med 2023; 53:595-613. [PMID: 36622556 PMCID: PMC9935749 DOI: 10.1007/s40279-022-01805-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2022] [Indexed: 01/10/2023]
Abstract
The physiological determinants of high-intensity exercise tolerance are important for both elite human performance and morbidity, mortality and disease in clinical settings. The asymptote of the hyperbolic relation between external power and time to task failure, critical power, represents the threshold intensity above which systemic and intramuscular metabolic homeostasis can no longer be maintained. After ~ 60 years of research into the phenomenon of critical power, a clear understanding of its physiological determinants has emerged. The purpose of the present review is to critically examine this contemporary evidence in order to explain the physiological underpinnings of critical power. Evidence demonstrating that alterations in convective and diffusive oxygen delivery can impact upon critical power is first addressed. Subsequently, evidence is considered that shows that rates of muscle oxygen utilisation, inferred via the kinetics of pulmonary oxygen consumption, can influence critical power. The data reveal a clear picture that alterations in the rates of flux along every step of the oxygen transport and utilisation pathways influence critical power. It is also clear that critical power is influenced by motor unit recruitment patterns. On this basis, it is proposed that convective and diffusive oxygen delivery act in concert with muscle oxygen utilisation rates to determine the intracellular metabolic milieu and state of fatigue within the myocytes. This interacts with exercising muscle mass and motor unit recruitment patterns to ultimately determine critical power.
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Tomanek RJ. The coronary capillary bed and its role in blood flow and oxygen delivery: A review. Anat Rec (Hoboken) 2022; 305:3199-3211. [PMID: 35521832 PMCID: PMC9796134 DOI: 10.1002/ar.24951] [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: 02/27/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 01/01/2023]
Abstract
The assumption that the coronary capillary blood flow is exclusively regulated by precapillary vessels is not supported by recent data. Rather, the complex coronary capillary bed has unique structural and geometric characteristics that invalidate many assumptions regarding red blood cell (RBC) transport, for example, data based on a single capillary or that increases in flow are the result of capillary recruitment. It is now recognized that all coronary capillaries are open and that their variations in flow are due to structural differences, local O2 demand and delivery, and variations in hematocrit. Recent data reveal that local mechanisms within the capillary bed regulate flow via signaling mechanisms involving RBC signaling and endothelial-associated pericytes that contract and relax in response to humoral and neural signaling. The discovery that pericytes respond to vasoactive signals (e.g., nitric oxide, phenylephrine, and adenosine) underscores the role of these cells in regulating capillary diameter and consequently RBC flux and oxygen delivery. RBCs also affect blood flow by sensing <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>P</mml:mi> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> </mml:math> and releasing nitric oxide to facilitate relaxation of pericytes and a consequential capillary dilation. New data indicate that these signaling mechanisms allow control of blood flow in specific coronary capillaries according to their oxygen requirements. In conclusion, mechanisms in the coronary capillary bed facilitate RBC density and transit time, hematocrit, blood flow and O2 delivery, factors that decrease capillary heterogeneity. These findings have important clinical implications for myocardial ischemia and infarction, as well as other vascular diseases.
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Affiliation(s)
- Robert J. Tomanek
- Department of Anatomy and Cell Biology, Carver College of MedicineUniversity of IowaIowa CityIAUSA
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Imperatrice M, Cuijpers I, Troost FJ, Sthijns MMJPE. Hesperidin Functions as an Ergogenic Aid by Increasing Endothelial Function and Decreasing Exercise-Induced Oxidative Stress and Inflammation, Thereby Contributing to Improved Exercise Performance. Nutrients 2022; 14:nu14142955. [PMID: 35889917 PMCID: PMC9316530 DOI: 10.3390/nu14142955] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/12/2022] [Accepted: 07/15/2022] [Indexed: 02/06/2023] Open
Abstract
The regulation of blood flow to peripheral muscles is crucial for proper skeletal muscle functioning and exercise performance. During exercise, increased mitochondrial oxidative phosphorylation leads to increased electron leakage and consequently induces an increase in ROS formation, contributing to DNA, lipid, and protein damage. Moreover, exercise may increase blood- and intramuscular inflammatory factors leading to a deterioration in endurance performance. The aim of this review is to investigate the potential mechanisms through which the polyphenol hesperidin could lead to enhanced exercise performance, namely improved endothelial function, reduced exercise-induced oxidative stress, and inflammation. We selected in vivo RCTs, animal studies, and in vitro studies in which hesperidin, its aglycone form hesperetin, hesperetin-metabolites, or orange juice are supplemented at any dosage and where the parameters related to endothelial function, oxidative stress, and/or inflammation have been measured. The results collected in this review show that hesperidin improves endothelial function (via increased NO availability), inhibits ROS production, decreases production and plasma levels of pro-inflammatory markers, and improves anaerobic exercise outcomes (e.g., power, speed, energy). For elite and recreational athletes, hesperidin could be used as an ergogenic aid to enhance muscle recovery between training sessions, optimize oxygen and nutrient supplies to the muscles, and improve anaerobic performance.
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Affiliation(s)
- Maria Imperatrice
- BioActor BV, Gaetano Martinolaan 50, 6229 GS Maastricht, The Netherlands
- Correspondence: (M.I.); (I.C.)
| | - Iris Cuijpers
- Food Innovation and Health, Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands; (F.J.T.); (M.M.J.P.E.S.)
- Correspondence: (M.I.); (I.C.)
| | - Freddy J. Troost
- Food Innovation and Health, Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands; (F.J.T.); (M.M.J.P.E.S.)
| | - Mireille M. J. P. E. Sthijns
- Food Innovation and Health, Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands; (F.J.T.); (M.M.J.P.E.S.)
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Mendelson AA, Ho E, Scott S, Vijay R, Hunter T, Milkovich S, Ellis CG, Goldman D. Capillary module hemodynamics and mechanisms of blood flow regulation in skeletal muscle capillary networks: Experimental and computational analysis. J Physiol 2022; 600:1867-1888. [DOI: 10.1113/jp282342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 01/19/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Asher A Mendelson
- Department of Medicine Section of Critical Care Medicine Rady Faculty of Health Sciences University of Manitoba Winnipeg Manitoba Canada
| | - Edward Ho
- Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada
| | - Shayla Scott
- Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada
| | - Raashi Vijay
- Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada
| | - Timothy Hunter
- Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada
| | - Stephanie Milkovich
- Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada
- Robarts Research Institute London Ontario Canada
| | - Christopher G Ellis
- Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada
- Robarts Research Institute London Ontario Canada
| | - Daniel Goldman
- Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada
- School of Biomedical Engineering Western University London Ontario Canada
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11
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Effects of pulmonary hypertension on microcirculatory hemodynamics in rat skeletal muscle. Microvasc Res 2022; 141:104334. [PMID: 35104507 PMCID: PMC8928216 DOI: 10.1016/j.mvr.2022.104334] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/12/2022] [Accepted: 01/25/2022] [Indexed: 11/20/2022]
Abstract
Pulmonary hypertension (PH) has previously been characterized as a disease of the pulmonary vasculature that subsequently results in myocardial dysfunction. Heart failure compromises skeletal muscle microvascular function, which contributes to exercise intolerance. Therefore, we tested the hypothesis that such changes might be present in PH. Thus, we investigated skeletal muscle oxygen (O2) transport in the rat model of PH to determine if O2 delivery (Q̇O2) is impaired at the level of the microcirculation as evidenced via reduced red blood cell (RBC) flux, velocity, hematocrit, and percentage of capillaries flowing in quiescent muscle. Adult male Sprague-Dawley rats were randomized into healthy (n = 9) and PH groups (n = 9). Progressive PH was induced via a one-time intraperitoneal injection of monocrotaline (MCT; 50 mg/kg) and rats were monitored weekly via echocardiography. Intravital microscopy in the spinotrapezius muscle was performed when echocardiograms confirmed moderate PH (preceding right ventricular (RV) failure). At 25 ± 9 days post-MCT, PH rats displayed RV hypertrophy (RV/(Left ventricle + Septum): 0.28 ± 0.05 vs. 0.44 ± 0.11), pulmonary congestion, and increased right ventricular systolic pressure (21 ± 8 vs. 55 ± 14 mm Hg) compared to healthy rats (all P < 0.05). Reduced capillary RBC velocity (403 ± 140 vs. 227 ± 84 μm/s; P = 0.01), RBC flux (33 ± 12 vs. 23 ± 5 RBCs/s; P = 0.04) and % of capillaries supporting continuous RBC flux at rest (79 ± 8 vs. 56 ± 13%; P = 0.01) were evident in PH rats compared to healthy rats. When Q̇O2 within a given field of view was quantified (RBC flux x % of capillaries supporting continuous RBC flux), PH rats demonstrated lower overall Q̇O2 (↓ 50%; P = 0.002). These data support that microcirculatory hemodynamic impairments (↓ Q̇O2 and therefore altered Q̇O2-to-V̇O2 matching) may compromise blood-myocyte O2 transport in PH. The mechanistic bases for decreased capillary RBC flux, velocity, and percentage of capillaries supporting RBC flow remains an important topic.
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Koirala B, Concas A, Sun Y, Gladden LB, Lai N. Blood volume versus deoxygenated NIRS signal: computational analysis of the effects muscle O 2 delivery and blood volume on the NIRS signals. J Appl Physiol (1985) 2021; 131:1418-1431. [PMID: 34528461 PMCID: PMC8906537 DOI: 10.1152/japplphysiol.00105.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 11/22/2022] Open
Abstract
Near-infrared spectroscopy (NIRS) signals quantify the oxygenated (ΔHbMbO2) and deoxygenated (ΔHHbMb) heme group concentrations. ΔHHbMb has been preferred to ΔHbMbO2 in evaluating skeletal muscle oxygen extraction because it is assumed to be less sensitive to blood volume (BV) changes, but uncertainties exist on this assumption. To analyze this assumption, a computational model of oxygen transport and metabolism is used to quantify the effect of O2 delivery and BV changes on the NIRS signals from a canine model of muscle oxidative metabolism (Sun Y, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Med Sci Sports Exerc 48: 2013-2020, 2016). The computational analysis accounts for microvascular (ΔHbO2, ΔHHb) and extravascular (ΔMbO2, ΔHMb) oxygenated and deoxygenated forms. Simulations predicted muscle oxygen uptake and NIRS signal changes well for blood flows ranging from resting to contracting muscle. Additional NIRS signal simulations were obtained in the absence or presence of BV changes corresponding to a heme groups concentration changes (ΔHbMb = 0-48 µM). Under normal delivery (Q = 1.0 L·kg-1·min-1) in contracting muscle, capillary oxygen saturation (So2) was 62% with capillary ΔHbO2 and ΔHHb of ± 41 µΜ for ΔHbMb = 0. An increase of BV (ΔHbMb = 24 µΜ) caused a ΔHbO2 decrease (16µΜ) almost twice as much as the increase observed for ΔHHb (9 µΜ). When So2 increased to more than 80%, only ΔHbO2 was significantly affected by BV changes. The analysis indicates that microvascular So2 is a key factor in determining the sensitivity of ΔHbMbO2 and deoxygenated ΔHHbMb to BV changes. Contrary to a common assumption, the ΔHHbMb is affected by BV changes in normal contracting muscle and even more in the presence of impaired O2 delivery.NEW & NOTEWORTHY Deoxygenated is preferred to the oxygenated near-infrared spectroscopy signal in evaluating skeletal muscle oxygen extraction because it is assumed to be insensitive to blood volume changes. The quantitative analysis proposed in this study indicates that even in absence of skin blood flow effects, both NIRS signals in presence of either normal or reduced oxygen delivery are affected by blood volume changes. These changes should be considered to properly quantify muscle oxygen extraction by NIRS methods.
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Affiliation(s)
- B. Koirala
- Department of Electrical and Computer Engineering,
Old Dominion University, Norfolk, Virginia
- Biomedical Engineering Institute, Old
Dominion University, Norfolk, Virginia
| | - A. Concas
- Center for Advanced Studies, Research and
Development in Sardinia (CRS4), Cagliari,
Italy
| | - Yi Sun
- Key Laboratory of Adolescent Health Assessment and
Exercise Intervention of Ministry of Education, East China Normal
University, Shanghai, China
- School of Physical Education & Health Care,
East China Normal University, Shanghai,
China
| | - L. B. Gladden
- School of Kinesiology, Auburn
University, Auburn, Alabama
| | - N. Lai
- Department of Mechanical, Chemical and Materials
Engineering, University of Cagliari, Cagliari,
Italy
- Department of Electrical and Computer Engineering,
Old Dominion University, Norfolk, Virginia
- Biomedical Engineering Institute, Old
Dominion University, Norfolk, Virginia
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13
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Dech S, Bittmann FN, Schaefer LV. Muscle Oxygenation Level Might Trigger the Regulation of Capillary Venous Blood Filling during Fatiguing Isometric Muscle Actions. Diagnostics (Basel) 2021; 11:1973. [PMID: 34829320 PMCID: PMC8621102 DOI: 10.3390/diagnostics11111973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 01/14/2023] Open
Abstract
The regulation of oxygen and blood supply during isometric muscle actions is still unclear. Recently, two behavioral types of oxygen saturation (SvO2) and relative hemoglobin amount (rHb) in venous microvessels were described during a fatiguing holding isometric muscle action (HIMA) (type I: nearly parallel behavior of SvO2 and rHb; type II: partly inverse behavior). The study aimed to ascertain an explanation of these two regulative behaviors. Twelve subjects performed one fatiguing HIMA trial with each arm by weight holding at 60% of the maximal voluntary isometric contraction (MVIC) in a 90° elbow flexion. Six subjects additionally executed one fatiguing PIMA trial by pulling on an immovable resistance with 60% of the MVIC with each side and same position. Both regulative types mentioned were found during HIMA (I: n = 7, II: n = 17) and PIMA (I: n = 3, II: n = 9). During the fatiguing measurements, rHb decreased initially and started to increase in type II at an average SvO2-level of 58.75 ± 2.14%. In type I, SvO2 never reached that specific value during loading. This might indicate the existence of a threshold around 59% which seems to trigger the increase in rHb and could explain the two behavioral types. An approach is discussed to meet the apparent incompatibility of an increased capillary blood filling (rHb) despite high intramuscular pressures which were found by other research groups during isometric muscle actions.
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Affiliation(s)
- Silas Dech
- Devision of Regulative Physiology and Prevention, Department of Sports and Health Sciences, University of Potsdam, 14476 Potsdam, Germany; (F.N.B.); (L.V.S.)
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14
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Effect of Microgravity Environment on Gut Microbiome and Angiogenesis. Life (Basel) 2021; 11:life11101008. [PMID: 34685381 PMCID: PMC8541308 DOI: 10.3390/life11101008] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 12/24/2022] Open
Abstract
Microgravity environments are known to cause a plethora of stressors to astronauts. Recently, it has become apparent that gut microbiome composition of astronauts is altered following space travel, and this is of significance given the important role of the gut microbiome in human health. Other changes observed in astronauts comprise reduced muscle strength and bone fragility, visual impairment, endothelial dysfunction, metabolic changes, behavior changes due to fatigue or stress and effects on mental well-being. However, the effects of microgravity on angiogenesis, as well as the connection with the gut microbiome are incompletely understood. Here, the potential association of angiogenesis with visual impairment, skeletal muscle and gut microbiome is proposed and explored. Furthermore, metabolites that are effectors of angiogenesis are deliberated upon along with their connection with gut bacterial metabolites. Targeting and modulating the gut microbiome may potentially have a profound influence on astronaut health, given its impact on overall human health, which is thus warranted given the likelihood of increased human activity in the solar system, and the determination to travel to Mars in future missions.
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15
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Smith JR, Berg JD, Curry TB, Joyner MJ, Olson TP. Respiratory muscle work influences locomotor convective and diffusive oxygen transport in human heart failure during exercise. Physiol Rep 2021; 8:e14484. [PMID: 32562374 PMCID: PMC7305241 DOI: 10.14814/phy2.14484] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 11/24/2022] Open
Abstract
Introduction It remains unclear if naturally occurring respiratory muscle (RM) work influences leg diffusive O2 transport during exercise in heart failure patients with reduced ejection fraction (HFrEF). In this retrospective study, we hypothesized that RM unloading during submaximal exercise will lead to increases in locomotor muscle O2 diffusion capacity (DMO2) contributing to the greater leg VO2. Methods Ten HFrEF patients and 10 healthy control matched participants performed two submaximal exercise bouts (i.e., with and without RM unloading). During exercise, leg blood flow was measured via constant infusion thermodilution. Intrathoracic pressure was measured via esophageal balloon. Radial arterial and femoral venous blood gases were measured and used to calculate leg arterial and venous content (CaO2 and CvO2, respectively), VO2, O2 delivery, and DMO2. Results From CTL to RM unloading, leg VO2, O2 delivery, and DMO2 were not different in healthy participants during submaximal exercise (all, p > .15). In HFrEF, leg VO2 (CTL: 0.7 ± 0.3 vs. RM unloading: 1.0 ± 0.4 L/min, p < .01), leg O2 delivery (CTL: 0.9 ± 0.4 vs. RM unloading: 1.4 ± 0.5 L/min, p < .01), and leg DMO2 (CTL: 31.5 ± 11.4 vs. RM unloading: 49.7 ± 18.6 ml min−1 mmHg−1) increased from CTL to RM unloading during submaximal exercise (all, p < .01), whereas CaO2‐CvO2 was not different (p = .51). The degree of RM unloading (i.e., % decrease in esophageal pressure‐time integral during inspiration) was related to the % increase in leg DMO2 with RM unloading (r = −.76, p = .01). Conclusion Our data suggest RM unloading leads to increased leg VO2 due to greater convective and diffusive O2 transport during submaximal exercise in HFrEF patients.
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Affiliation(s)
- Joshua R Smith
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jessica D Berg
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Timothy B Curry
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Michael J Joyner
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Thomas P Olson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
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16
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Hirai DM, Tabuchi A, Craig JC, Colburn TD, Musch TI, Poole DC. Regulation of capillary hemodynamics by K ATP channels in resting skeletal muscle. Physiol Rep 2021; 9:e14803. [PMID: 33932103 PMCID: PMC8087980 DOI: 10.14814/phy2.14803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 02/22/2021] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive K+ channels (KATP ) have been implicated in the regulation of resting vascular smooth muscle membrane potential and tone. However, whether KATP channels modulate skeletal muscle microvascular hemodynamics at the capillary level (the primary site for blood-myocyte O2 exchange) remains unknown. We tested the hypothesis that KATP channel inhibition would reduce the proportion of capillaries supporting continuous red blood cell (RBC) flow and impair RBC hemodynamics and distribution in perfused capillaries within resting skeletal muscle. RBC flux (fRBC ), velocity (VRBC ), and capillary tube hematocrit (Hctcap ) were assessed via intravital microscopy of the rat spinotrapezius muscle (n = 6) under control (CON) and glibenclamide (GLI; KATP channel antagonist; 10 µM) superfusion conditions. There were no differences in mean arterial pressure (CON:120 ± 5, GLI:124 ± 5 mmHg; p > 0.05) or heart rate (CON:322 ± 32, GLI:337 ± 33 beats/min; p > 0.05) between conditions. The %RBC-flowing capillaries were not altered between conditions (CON:87 ± 2, GLI:85 ± 1%; p > 0.05). In RBC-perfused capillaries, GLI reduced fRBC (CON:20.1 ± 1.8, GLI:14.6 ± 1.3 cells/s; p < 0.05) and VRBC (CON:240 ± 17, GLI:182 ± 17 µm/s; p < 0.05) but not Hctcap (CON:0.26 ± 0.01, GLI:0.26 ± 0.01; p > 0.05). The absence of GLI effects on the %RBC-flowing capillaries and Hctcap indicates preserved muscle O2 diffusing capacity (DO2 m). In contrast, GLI lowered both fRBC and VRBC thus impairing perfusive microvascular O2 transport (Q̇m) and lengthening RBC capillary transit times, respectively. Given the interdependence between diffusive and perfusive O2 conductances (i.e., %O2 extraction∝DO2 m/Q̇m), such GLI alterations are expected to elevate muscle %O2 extraction to sustain a given metabolic rate. These results support that KATP channels regulate capillary hemodynamics and, therefore, microvascular gas exchange in resting skeletal muscle.
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Affiliation(s)
- Daniel M. Hirai
- Department of Health and KinesiologyPurdue UniversityWest LafayetteIndianaUSA,Department of KinesiologyKansas State UniversityManhattanKansasUSA
| | - Ayaka Tabuchi
- Department of KinesiologyKansas State UniversityManhattanKansasUSA,Department of Engineering ScienceUniversity of Electro‐CommunicationsTokyoJapan
| | - Jesse C. Craig
- Department of KinesiologyKansas State UniversityManhattanKansasUSA,Department of Internal MedicineUniversity of UtahSalt Lake CityUtahUSA,Geriatric ResearchEducation and Clinical CenterVeterans Affairs Medical CenterSalt Lake CityUtahUSA
| | | | - Timothy I. Musch
- Department of KinesiologyKansas State UniversityManhattanKansasUSA,Department of Anatomy and PhysiologyKansas State UniversityManhattanKansasUSA
| | - David C. Poole
- Department of KinesiologyKansas State UniversityManhattanKansasUSA,Department of Anatomy and PhysiologyKansas State UniversityManhattanKansasUSA
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17
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Mendelson AA, Milkovich S, Hunter T, Vijay R, Choi YH, Milkovich S, Ho E, Goldman D, Ellis CG. The capillary fascicle in skeletal muscle: Structural and functional physiology of RBC distribution in capillary networks. J Physiol 2021; 599:2149-2168. [PMID: 33595111 DOI: 10.1113/jp281172] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/04/2021] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS The capillary module, consisting of parallel capillaries from arteriole to venule, is classically considered as the building block of complex capillary networks. In skeletal muscle, this structure fails to address how blood flow is regulated along the entire length of the synchronously contracting muscle fibres. Using intravital video microscopy of resting extensor digitorum longus muscle in rats, we demonstrated the capillary fascicle as a series of interconnected modules forming continuous columns that align naturally with the dimensions of the muscle fascicle. We observed structural heterogeneity for module topology, and functional heterogeneity in space and time for capillary-red blood cell (RBC) haemodynamics within a module and between modules. We found that module RBC haemodynamics were independent of module resistance, providing direct evidence for microvascular flow regulation at the level of the capillary module. The capillary fascicle is an updated paradigm for characterizing blood flow and RBC distribution in skeletal muscle capillary networks. ABSTRACT Capillary networks are the fundamental site of oxygen exchange in the microcirculation. The capillary module (CM), consisting of parallel capillaries from terminal arteriole (TA) to post-capillary venule (PCV), is classically considered as the building block of complex capillary networks. In skeletal muscle, this structure fails to address how blood flow is regulated along the entire length of the synchronously contracting muscle fibres, requiring co-ordination from numerous modules. It has previously been recognized that TAs and PCVs interact with multiple CMs, creating interconnected networks. Using label-free intravital video microscopy of resting extensor digitorum longus muscle in rats, we found that these networks form continuous columns of linked CMs spanning thousands of microns, herein denoted as the capillary fascicle (CF); this structure aligns naturally with the dimensions of the muscle fascicle. We measured capillary-red blood cell (RBC) haemodynamics and module topology (n = 9 networks, 327 modules, 1491 capillary segments). The average module had length 481 μm, width 157 μm and 9.51 parallel capillaries. We observed structural heterogeneity for CM topology, and functional heterogeneity in space and time for capillary-RBC haemodynamics within a module and between modules. There was no correlation between capillary RBC velocity and lineal density. A passive inverse relationship between module length and haemodynamics was remarkably absent, providing direct evidence for microvascular flow regulation at the level of the CM. In summary, the CF is an updated paradigm for characterizing RBC distribution in skeletal muscle, and strengthens the theory of capillary networks as major contributors to the signal that regulates capillary perfusion.
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Affiliation(s)
- Asher A Mendelson
- Department of Medicine, Section of Critical Care Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Stephanie Milkovich
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Timothy Hunter
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Raashi Vijay
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Yun-Hee Choi
- Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Shaun Milkovich
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Edward Ho
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Daniel Goldman
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.,Department of Applied Mathematics, Faculty of Science, Western University, London, Ontario, Canada
| | - Christopher G Ellis
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.,Robarts Research Institute, London, Ontario, Canada
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18
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Unraveling the Role of Respiratory Muscle Metaboloreceptors under Inspiratory Training in Patients with Heart Failure. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041697. [PMID: 33578776 PMCID: PMC7916511 DOI: 10.3390/ijerph18041697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/01/2021] [Accepted: 02/06/2021] [Indexed: 12/15/2022]
Abstract
Exercise intolerance may be considered a hallmark in patients who suffer from heart failure (HF) syndrome. Currently, there is enough scientific evidence regarding functional and structural deterioration of skeletal musculature in these patients. It is worth noting that muscle weakness appears first in the respiratory muscles and then in the musculature of the limbs, which may be considered one of the main causes of exercise intolerance. Functional deterioration and associated atrophy of these respiratory muscles are related to an increased muscle metaboreflex leading to sympathetic–adrenal system hyperactivity and increased pulmonary ventilation. This issue contributes to increased dyspnea and/or fatigue and decreased aerobic function. Consequently, respiratory muscle weakness produces exercise limitations in these patients. In the present review, the key role that respiratory muscle metaboloreceptors play in exercise intolerance is accurately addressed in patients who suffer from HF. In conclusion, currently available scientific evidence seems to affirm that excessive metaboreflex activity of respiratory musculature under HF is the main cause of exercise intolerance and sympathetic–adrenal system hyperactivity. Inspiratory muscle training seems to be a useful personalized medicine intervention to reduce respiratory muscle metaboreflex in order to increase patients’ exercise tolerance under HF condition.
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19
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Blervaque L, Pomiès P, Rossi E, Catteau M, Blandinières A, Passerieux E, Blaquière M, Ayoub B, Molinari N, Mercier J, Perez-Martin A, Marchi N, Smadja DM, Hayot M, Gouzi F. COPD is deleterious for pericytes: implications during training-induced angiogenesis in skeletal muscle. Am J Physiol Heart Circ Physiol 2020; 319:H1142-H1151. [PMID: 32986960 DOI: 10.1152/ajpheart.00306.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Improvements in skeletal muscle endurance and oxygen uptake are blunted in patients with chronic obstructive pulmonary disease (COPD), possibly because of a limitation in the muscle capillary oxygen supply. Pericytes are critical for capillary blood flow adaptation during angiogenesis but may be impaired by COPD systemic effects, which are mediated by circulating factors. This study compared the pericyte coverage of muscle capillaries in response to 10 wk of exercise training in patients with COPD and sedentary healthy subjects (SHS). Fourteen patients with COPD were compared with seven matched SHS. SHS trained at moderate intensity corresponding to an individualized moderate-intensity patient with COPD trained at the same relative (%V̇o2: COPD-RI) or absolute (mL·min-1·kg-1: COPD-AI) intensity as SHS. Capillary-to-fiber ratio (C/F) and NG2+ pericyte coverage were assessed from vastus lateralis muscle biopsies, before and after 5 and 10 wk of training. We also tested in vitro the effect of COPD and SHS serum on pericyte morphology and mesenchymal stem cell (MSC) differentiation into pericytes. SHS showed greater improvement in aerobic capacity (V̇o2VT) than both patients with COPD-RI and patients with COPD-AI (Group × Time: P = 0.004). Despite a preserved increase in the C/F ratio, NG2+ pericyte coverage did not increase in patients with COPD in response to training, contrary to SHS (Group × Time: P = 0.011). Conversely to SHS serum, COPD serum altered pericyte morphology (P < 0.001) and drastically reduced MSC differentiation into pericytes (P < 0.001). Both functional capacities and pericyte coverage responses to exercise training are blunted in patients with COPD. We also provide direct evidence of the deleterious effect of COPD circulating factors on pericyte morphology and differentiation.NEW & NOTEWORTHY This work confirms the previously reported impairment in the functional response to exercise training of patients with COPD compared with SHS. Moreover, it shows for the first time that pericyte coverage of the skeletal capillaries is drastically reduced in patients with COPD compared with SHS during training-induced angiogenesis. Finally, it provides experimental evidence that circulating factors are involved in the impaired pericyte coverage of patients with COPD.
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Affiliation(s)
- Léo Blervaque
- PhyMedExp, INSERM-CNRS-Montpellier University, Montpellier, France
| | - Pascal Pomiès
- PhyMedExp, INSERM-CNRS-Montpellier University, Montpellier, France
| | - Elisa Rossi
- Université de Paris, Innovative Therapies in Haemostasis, INSERM, Paris, France
| | - Matthias Catteau
- PhyMedExp, INSERM-CNRS-Montpellier University, Montpellier, France
| | - Adeline Blandinières
- Service d'Hématologie et Laboratoire de Recherches Biochirugicales (Fondation Carpentier), AH-HP, Georges Pompidou European Hospital, Paris, France
| | | | - Marine Blaquière
- Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France
| | - Bronia Ayoub
- PhyMedExp, INSERM-CNRS-Montpellier University, CHU Montpellier, Montpellier, France
| | - Nicolas Molinari
- IMAG, CNRS, Montpellier University, CHU Montpellier, Montpellier, France
| | - Jacques Mercier
- PhyMedExp, INSERM-CNRS-Montpellier University, CHU Montpellier, Montpellier, France
| | - Antonia Perez-Martin
- Vascular Medicine Department and Laboratory, CHU Nîmes and EA2992 Research Unit, Montpellier University, Nimes, France
| | - Nicola Marchi
- Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France
| | - David M Smadja
- Service d'Hématologie et Laboratoire de Recherches Biochirugicales (Fondation Carpentier), AH-HP, Georges Pompidou European Hospital, Paris, France
| | - Maurice Hayot
- PhyMedExp, INSERM-CNRS-Montpellier University, CHU Montpellier, Montpellier, France
| | - Fares Gouzi
- PhyMedExp, INSERM-CNRS-Montpellier University, CHU Montpellier, Montpellier, France
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20
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Poole DC, Pittman RN, Musch TI, Østergaard L. August Krogh's theory of muscle microvascular control and oxygen delivery: a paradigm shift based on new data. J Physiol 2020; 598:4473-4507. [PMID: 32918749 DOI: 10.1113/jp279223] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022] Open
Abstract
August Krogh twice won the prestigious international Steegen Prize, for nitrogen metabolism (1906) and overturning the concept of active transport of gases across the pulmonary epithelium (1910). Despite this, at the beginning of 1920, the consummate experimentalist was relatively unknown worldwide and even among his own University of Copenhagen faculty. But, in early 1919, he had submitted three papers to Dr Langley, then editor of The Journal of Physiology in England. These papers coalesced anatomical observations of skeletal muscle capillary numbers with O2 diffusion theory to propose a novel active role for capillaries that explained the prodigious increase in blood-muscle O2 flux from rest to exercise. Despite his own appraisal of the first two papers as "rather dull" to his friend, the eminent Cambridge respiratory physiologist, Joseph Barcroft, Krogh believed that the third one, dealing with O2 supply and capillary regulation, was"interesting". These papers, which won Krogh an unopposed Nobel Prize for Physiology or Medicine in 1920, form the foundation for this review. They single-handedly transformed the role of capillaries from passive conduit and exchange vessels, functioning at the mercy of their upstream arterioles, into independent contractile units that were predominantly closed at rest and opened actively during muscle contractions in a process he termed 'capillary recruitment'. Herein we examine Krogh's findings and some of the experimental difficulties he faced. In particular, the boundary conditions selected for his model (e.g. heavily anaesthetized animals, negligible intramyocyte O2 partial pressure, binary open-closed capillary function) have not withstood the test of time. Subsequently, we update the reader with intervening discoveries that underpin our current understanding of muscle microcirculatory control and place a retrospectroscope on Krogh's discoveries. The perspective is presented that the imprimatur of the Nobel Prize, in this instance, may have led scientists to discount compelling evidence. Much as he and Marie Krogh demonstrated that active transport of gases across the blood-gas barrier was unnecessary in the lung, capillaries in skeletal muscle do not open and close spontaneously or actively, nor is this necessary to account for the increase in blood-muscle O2 flux during exercise. Thus, a contemporary model of capillary function features most muscle capillaries supporting blood flow at rest, and, rather than capillaries actively vasodilating from rest to exercise, increased blood-myocyte O2 flux occurs predominantly via elevating red blood cell and plasma flux in already flowing capillaries. Krogh is lauded for his brilliance as an experimentalist and for raising scientific questions that led to fertile avenues of investigation, including the study of microvascular function.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Roland N Pittman
- Department of Physiology and Biophysics, Virginia Commonwealth University Richmond, Richmond, VA, 23298-0551, USA
| | - Timothy I Musch
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
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21
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Goulding RP, Okushima D, Marwood S, Poole DC, Barstow TJ, Lei TH, Kondo N, Koga S. Impact of supine exercise on muscle deoxygenation kinetics heterogeneity: mechanistic insights into slow pulmonary oxygen uptake dynamics. J Appl Physiol (1985) 2020; 129:535-546. [PMID: 32702271 DOI: 10.1152/japplphysiol.00213.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Oxygen uptake (V̇o2) kinetics are slowed in the supine (S) position purportedly due to impaired muscle O2 delivery ([Formula: see text]); however, these conclusions are predicated on single-site measurements in superficial muscle using continuous-wave near-infrared spectroscopy (NIRS). This study aimed to determine the impact of body position [i.e., upright (U) versus S] on deep and superficial muscle deoxygenation (deoxy[heme]) using time-resolved (TR-) NIRS, and how these relate to slowed pulmonary V̇o2 kinetics. Seventeen healthy men completed constant power tests during 1) S heavy-intensity exercise and 2) U exercise at the same absolute work rate, with a subset of 10 completing additional tests at the same relative work rate as S. Pulmonary V̇o2 was measured breath-by-breath and, deoxy- and total[heme] were resolved via TR-NIRS in the superficial and deep vastus lateralis and superficial rectus femoris. The fundamental phase V̇o2 time constant was increased during S compared with U (S: 36 ± 10 vs. U: 27 ± 8 s; P < 0.001). The deoxy[heme] amplitude (S: 25-28 vs. U: 13-18 µM; P < 0.05) and total[heme] amplitude (S: 17-20 vs. U: 9-16 µM; P < 0.05) were greater in S compared with U and were consistent for the same absolute (above data) and relative work rates (n = 10, all P < 0.05). The greater deoxy- and total[heme] amplitudes in S vs. U supports that reduced perfusive [Formula: see text] in S, even within deep muscle, necessitated a greater reliance on fractional O2 extraction and diffusive [Formula: see text]. The slower V̇o2 kinetics in S versus U demonstrates that, ultimately, these adjustments were insufficient to prevent impairments in whole body oxidative metabolism.NEW & NOTEWORTHY We show that supine exercise causes a greater degree of muscle deoxygenation in both deep and superficial muscle and increases the spatial heterogeneity of muscle deoxygenation. Therefore, this study suggests that any O2 delivery gradient toward deep versus superficial muscle is insufficient to mitigate impairments in oxidative function in response to reduced whole muscle O2 delivery. More heterogeneous muscle deoxygenation is associated with slower V̇o2 kinetics.
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Affiliation(s)
- Richie P Goulding
- Applied Physiology Laboratory, Kobe Design University, Kobe, Japan.,International Research Fellow of Japan Society for Promotion of Sciences, Tokyo, Japan
| | - Dai Okushima
- Osaka International University, Moriguchi, Japan
| | - Simon Marwood
- School of Health Sciences, Liverpool Hope University, Liverpool, Merseyside, United Kingdom
| | - David C Poole
- Departments of Anatomy and Physiology, and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Thomas J Barstow
- Departments of Anatomy and Physiology, and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Tze-Huan Lei
- International Research Fellow of Japan Society for Promotion of Sciences, Tokyo, Japan.,Applied Physiology Laboratory, Kobe University, Kobe, Japan
| | - Narihiko Kondo
- Applied Physiology Laboratory, Kobe University, Kobe, Japan
| | - Shunsaku Koga
- Applied Physiology Laboratory, Kobe Design University, Kobe, Japan
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22
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Limb blood flow and muscle oxygenation responses during handgrip exercise above vs. below critical force. Microvasc Res 2020; 131:104002. [PMID: 32198059 DOI: 10.1016/j.mvr.2020.104002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/14/2020] [Accepted: 03/14/2020] [Indexed: 11/20/2022]
Abstract
This study compared the brachial artery blood flow (Q̇BA) and microvascular oxygen delivery responses during handgrip exercise above vs. below critical force (CF; the isometric analog of critical power). Q̇BA and microvascular oxygen delivery are important determinants of oxygen utilization and metabolite accumulation during exercise, both of which increase progressively during exercise above CF. However the Q̇BA and microvascular oxygen delivery responses above vs. below CF remain unknown. We hypothesized that Q̇BA, deoxygenated-heme (deoxy-[heme]; an estimate of microvascular fractional oxygen extraction), and total-heme concentrations (total-[heme]; an estimate of changes in microvascular hematocrit) would demonstrate physiological maximums above CF despite increases in exercise intensity. Seven men and six women performed 1) a 5-min rhythmic isometric-handgrip maximal-effort test (MET) to determine CF and 2) two constant target-force tests above (severe-intensity; S1 and S2) and two constant target-force tests below (heavy-intensity; H1 and H2) CF. CF was 189.3 ± 16.7 N (29.7 ± 1.6%MVC). At end-exercise, Q̇BA was greater for tests above CF (S1: 418 ± 147 mL/min; S2: 403 ± 137 mL/min) compared to tests below CF (H1: 287 ± 97 mL/min; H2: 340 ± 116 mL/min; all p < 0.05) but was not different between S1 and S2. Further, end-test Q̇BA during both tests above CF was not different from Q̇BA estimated at CF (392 ± 37 mL/min). At end-exercise, deoxy-[heme] was not different between tests above CF (S1: 150 ± 50 μM; S2: 155 ± 57 μM), but was greater during tests above CF compared to tests below CF (H1: 101 ± 24 μM; H2: 111 ± 21 μM; all p < 0.05). At end-exercise, total-[heme] was not different between tests above CF (S1: 404 ± 58 μM; S2: 397 ± 73 μM), but was greater during tests above CF compared to H1 (352 ± 58 μM; p < 0.01) but not H2 (371 ± 57 μM). These data suggest limb blood flow limitations exist and maximal levels of muscle microvascular oxygen delivery and extraction occur during exercise above, but not below, CF.
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23
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Okushima D, Poole DC, Barstow TJ, Kondo N, Chin LMK, Koga S. Effect of differential muscle activation patterns on muscle deoxygenation and microvascular haemoglobin regulation. Exp Physiol 2020; 105:531-541. [PMID: 31944446 PMCID: PMC10466155 DOI: 10.1113/ep088322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/14/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does the presence and extent of heterogeneity in the ratio of O2 delivery to uptake across human muscles relate specifically to different muscle activation patterns? What is the main finding and its importance? During ramp incremental knee-extension and cycling exercise, the profiles of muscle deoxygenation (deoxy[haemoglobin + myoglobin]) and diffusive O2 potential (total[haemoglobin + myoglobin]) in the vastus lateralis corresponded to different muscle activation strategies. However, this was not the case for the rectus femoris, where muscle activation and deoxygenation profiles were dissociated and might therefore be determined by other structural and/or functional attributes (e.g. arteriolar vascular regulation and control of red blood cell flux). ABSTRACT Near-infrared spectroscopy has revealed considerable heterogeneity in the ratio of O2 delivery to uptake as identified by disparate deoxygenation {deoxy[haemoglobin + myoglobin] (deoxy[Hb + Mb])} values in the exercising quadriceps. However, whether this represents a recruitment phenomenon or contrasting vascular and metabolic control, as seen among fibre types, has not been established. We used knee-extension (KE) and cycling (CE) incremental exercise protocols to examine whether differential muscle activation profiles could account for the heterogeneity of deoxy[Hb + Mb] and microvascular haemoconcentration (i.e. total[Hb + Mb]). Using time-resolved near-infrared spectroscopy for the quadriceps femoris (vastus lateralis and rectus femoris) during exhaustive ramp exercise in eight participants, we tested the following hypotheses: (i) the deoxy[Hb + Mb] (i.e. fractional O2 extraction) would relate to muscle activation levels across exercise protocols; and (ii) KE would induce greater total[Hb + Mb] (i.e. diffusive O2 potential) at task failure (i.e. peak O2 uptake) than CE irrespective of muscle site. At a given level of muscle activation, as assessed by the relative integrated EMG normalized to maximal voluntary contraction (%iEMGmax ), the vastus lateralis deoxy[Hb + Mb] profile was not different between exercise protocols. However, at peak O2 uptake and until 20% iEMGmax for CE, rectus femoris exhibited a lower deoxy[Hb + Mb] (83.2 ± 15.5 versus 98.2 ± 19.4 μm) for KE than for CE (P < 0.05). The total[Hb + Mb] at peak O2 uptake was not different between exercise protocols for either muscle site. These data support the hypothesis that the contrasting patterns of convective and diffusive O2 transport correspond to different muscle activation patterns in vastus lateralis but not rectus femoris. Thus, the differential deoxygenation profiles for rectus femoris across exercise protocols might be dependent upon specific facets of muscle architecture and functional haemodynamic events.
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Affiliation(s)
- Dai Okushima
- Applied Physiology Laboratory, Kobe Design University, Kobe, Hyogo, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
- Osaka International University, Moriguchi, Japan
| | - David C. Poole
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Thomas J. Barstow
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | | | - Lisa M. K. Chin
- Rehabilitation Medicine Department, National Institutes of Health Clinical Center, Bethesda, Maryland
| | - Shunsaku Koga
- Applied Physiology Laboratory, Kobe Design University, Kobe, Hyogo, Japan
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24
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Dominelli PB, Wiggins CC, Baker SE, Shepherd JRA, Roberts SK, Roy TK, Curry TB, Hoyer JD, Oliveira JL, Joyner MJ. Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise. J Physiol 2020; 598:1475-1490. [PMID: 31923331 DOI: 10.1113/jp279161] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/20/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin. We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance. The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia. Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts. High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange. ABSTRACT The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n = 11, n = 8 females) with HAH (P50 = 16 ± 1 mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P50 = 26 ± 1, n = 14, n = 8 females). Cardiorespiratory and arterial blood gases were collected throughout both exercise tests. Despite no difference in end-exercise arterial oxygen tension in hypoxia (59 ± 6 vs. 59 ± 9 mmHg for controls and HAH, respectively), the HAH subjects' oxyhaemoglobin saturation ( S a , O 2 ) was ∼7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake ( V ̇ O 2 max ) (4 ± 5% vs. 12 ± %, p < 0.001) in hypoxia and the change in V ̇ O 2 max between trials was related to the change in S a O 2 (r = -0.75, p < 0.0001). Compared to normoxia, the controls' alveolar-to-arterial oxygen gradient significantly increased during hypoxic exercise, whereas pulmonary gas exchange in HAH subjects was unchanged between the two exercise trials. However, arterial lactate was significantly higher and arterial pH significantly lower in the HAH subjects for both exercise trials. We conclude that HAH attenuates the decline in maximal aerobic capacity and preserves pulmonary gas exchange during acute hypoxic exercise. Our data support the comparative biology literature indicating that HAH is a positive adaptation to acute hypoxia.
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Affiliation(s)
- Paolo B Dominelli
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Chad C Wiggins
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sarah E Baker
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - John R A Shepherd
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Shelly K Roberts
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Tuhin K Roy
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Timothy B Curry
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - James D Hoyer
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Jennifer L Oliveira
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Michael J Joyner
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
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25
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Angleys H, Østergaard L. Krogh’s capillary recruitment hypothesis, 100 years on: Is the opening of previously closed capillaries necessary to ensure muscle oxygenation during exercise? Am J Physiol Heart Circ Physiol 2020; 318:H425-H447. [DOI: 10.1152/ajpheart.00384.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In 1919, August Krogh published his seminal work on skeletal muscle oxygenation. Krogh’s observations indicated that muscle capillary diameter is actively regulated, rather than a passive result of arterial blood flow regulation. Indeed, combining a mathematical model with the number of ink-filled capillaries he observed in muscle cross sections taken at different workloads, Krogh was able to account for muscle tissue’s remarkably efficient oxygen extraction during exercise in terms of passive diffusion from nearby capillaries. Krogh was awarded the 1920 Nobel Prize for his account of muscle oxygenation. Today, his observations are engrained in the notion of capillary recruitment: the opening of previously closed capillaries. While the binary distinction between “closed” and “open” was key to Krogh’s model argument, he did in fact report a continuum of capillary diameters, degrees of erythrocyte deformation, and perfusion states. Indeed, modern observations question the presence of closed muscle capillaries. We therefore examined whether changes in capillary flow patterns and hematocrit among open capillaries can account for oxygen extraction in muscle across orders-of-magnitude changes in blood flow. Our four-compartment model of oxygen extraction in muscle confirms this notion and provides a framework for quantifying the impact of changes in microvascular function on muscle oxygenation in health and disease. Our results underscore the importance of capillary function for oxygen extraction in muscle tissue as first proposed by Krogh. While Krogh’s model calculations still hold, our model predictions support that capillary recruitment can be viewed in the context of continuous, rather than binary, erythrocyte distributions among capillaries. NEW & NOTEWORTHY Oxygen extraction in working muscle is extremely efficient in view of single capillaries properties. The underlying mechanisms have been widely debated. Here, we develop a four-compartment model to quantify the influence of each of the hypothesized mechanisms on muscle oxygenation. Our results show that changes in capillary flow pattern and hematocrit can account for the high oxygen extraction observed in working muscle, while capillary recruitment is not required to account for these extraction properties.
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Affiliation(s)
- Hugo Angleys
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark
- Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
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26
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Broxterman RM, Hoff J, Wagner PD, Richardson R. Determinants of the diminished exercise capacity in patients with chronic obstructive pulmonary disease: looking beyond the lungs. J Physiol 2020; 598:599-610. [PMID: 31856306 PMCID: PMC6995414 DOI: 10.1113/jp279135] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/06/2019] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Peak oxygen uptake, a primary determinant of prognosis, mortality and quality of life, is diminished in patients with chronic obstructive pulmonary disease (COPD), with mounting evidence supporting an important role for peripheral dysfunction, particularly within skeletal muscle. In patients with severe COPD and activity-matched controls, muscle oxygen transport and utilization were assessed at peak effort during single-leg knee-extensor exercise (KE), where ventilation is assumed to be submaximal. This strategy removes ventilation as the major constraint to exercise capacity in COPD, allowing maximal muscle function to be attained and evaluated. During maximal KE, both convective arterial oxygen delivery to the skeletal muscle microvasculature and subsequent diffusive oxygen delivery to the mitochondria were diminished in patients with COPD compared to control subjects. These findings emphasize the importance of factors, beyond the lungs, that influence exercise capacity in this patient population and may, ultimately, influence the prognosis, mortality and quality of life for patients with COPD. ABSTRACT Peak oxygen uptake ( V ̇ O 2 peak ), a primary determinant of prognosis, mortality and quality of life, is diminished in patients with chronic obstructive pulmonary disease (COPD). Mounting evidence supports an important role of the periphery, particularly skeletal muscle, in the diminished V ̇ O 2 peak with COPD. However, the peripheral determinants of V ̇ O 2 peak have not been comprehensively assessed in this cohort. Thus, the hypothesis was tested that both muscle convective and diffusive oxygen (O2 ) transport, and therefore skeletal muscle peak O2 uptake ( V ̇ M O 2 peak ), are diminished in patients with COPD compared to matched healthy controls, even when ventilatory limitations (i.e. attainment of maximal ventilation) are minimized by using small muscle mass exercise. Muscle O2 transport and utilization were assessed at peak exercise from femoral arterial and venous blood samples and leg blood flow (by thermodilution) in eight patients with severe COPD (forced expiratory volume in 1s (FEV1 ) ± SEM = 0.9 ± 0.1 l, 30% of predicted) and eight controls during single-leg knee-extensor exercise. Both muscle convective O2 delivery (0.44 ± 0.06 vs. 0.69 ± 0.07 l min-1 , P < 0.05) and muscle diffusive O2 conductance (6.6 ± 0.8 vs. 10.4 ± 0.9 ml min-1 mmHg-1 , P < 0.05) were ∼1/3 lower in patients with COPD than controls, resulting in an attenuated V ̇ M O 2 peak in the patients (0.27 ± 0.04 vs. 0.42 ± 0.05 l min-1 , P < 0.05). When cardiopulmonary limitations to exercise are minimized, the convective and diffusive determinants of V ̇ M O 2 peak , at the level of the skeletal muscle, are greatly attenuated in patients with COPD. These findings emphasize the importance of factors, beyond the lungs, that may ultimately influence this population's prognosis, mortality and quality of life.
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Affiliation(s)
- Ryan M. Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, Utah
| | - Jan Hoff
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Peter D. Wagner
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Russell.S. Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, Utah
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
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27
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Lewis MT, Kasper JD, Bazil JN, Frisbee JC, Wiseman RW. Quantification of Mitochondrial Oxidative Phosphorylation in Metabolic Disease: Application to Type 2 Diabetes. Int J Mol Sci 2019; 20:E5271. [PMID: 31652915 PMCID: PMC6862501 DOI: 10.3390/ijms20215271] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/17/2019] [Accepted: 10/22/2019] [Indexed: 12/17/2022] Open
Abstract
Type 2 diabetes (T2D) is a growing health concern with nearly 400 million affected worldwide as of 2014. T2D presents with hyperglycemia and insulin resistance resulting in increased risk for blindness, renal failure, nerve damage, and premature death. Skeletal muscle is a major site for insulin resistance and is responsible for up to 80% of glucose uptake during euglycemic hyperglycemic clamps. Glucose uptake in skeletal muscle is driven by mitochondrial oxidative phosphorylation and for this reason mitochondrial dysfunction has been implicated in T2D. In this review we integrate mitochondrial function with physiologic function to present a broader understanding of mitochondrial functional status in T2D utilizing studies from both human and rodent models. Quantification of mitochondrial function is explained both in vitro and in vivo highlighting the use of proper controls and the complications imposed by obesity and sedentary lifestyle. This review suggests that skeletal muscle mitochondria are not necessarily dysfunctional but limited oxygen supply to working muscle creates this misperception. Finally, we propose changes in experimental design to address this question unequivocally. If mitochondrial function is not impaired it suggests that therapeutic interventions and drug development must move away from the organelle and toward the cardiovascular system.
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Affiliation(s)
- Matthew T Lewis
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA.
| | - Jonathan D Kasper
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA.
- Present address: Molecular Physiology Institute, Duke University, Durham, NC 27701, USA.
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA.
| | - Jefferson C Frisbee
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 3K7, Canada.
| | - Robert W Wiseman
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA.
- Department of Radiology, Michigan State University, East Lansing, MI 48824, USA.
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28
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Hirai DM, Craig JC, Colburn TD, Eshima H, Kano Y, Musch TI, Poole DC. Skeletal muscle interstitial Po 2 kinetics during recovery from contractions. J Appl Physiol (1985) 2019; 127:930-939. [PMID: 31369325 DOI: 10.1152/japplphysiol.00297.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The oxygen partial pressure in the interstitial space (Po2 is) drives O2 into the myocyte via diffusion, thus supporting oxidative phosphorylation. Although crucial for metabolic recovery and the capacity to perform repetitive tasks, the time course of skeletal muscle Po2 is during recovery from contractions remains unknown. We tested the hypothesis that Po2 is would recover to resting values and display considerable on-off asymmetry (fast on-, slow off-kinetics), reflective of asymmetric capillary hemodynamics. Microvascular Po2 (Po2 mv) was also evaluated to test the hypothesis that a significant transcapillary gradient (ΔPo2 = Po2 mv - Po2 is) would be sustained during recovery. Po2 mv and Po2 is (expressed in mmHg) were determined via phosphorescence quenching in the exposed rat spinotrapezius muscle during and after submaximal twitch contractions (n = 12). Po2 is rose exponentially (P < 0.05) from end-contraction (11.1 ± 5.1), such that the end-recovery value (17.9 ± 7.9) was not different from resting Po2 is (18.5 ± 8.1; P > 0.05). Po2 is off-kinetics were slower than on-kinetics (mean response time: 53.1 ± 38.3 versus 18.5 ± 7.3 s; P < 0.05). A significant transcapillary ΔPo2 observed at end-contraction (16.6 ± 7.4) was maintained throughout recovery (end-recovery: 18.8 ± 9.6; P > 0.05). Consistent with our hypotheses, muscle Po2 is recovered to resting values with slower off-kinetics compared with the on-transient in line with the on-off asymmetry for capillary hemodynamics. Maintenance of a substantial transcapillary ΔPo2 during recovery supports that the microvascular-interstitium interface provides considerable resistance to O2 transport. As dictated by Fick's law (V̇o2 = Do2 × ΔPo2), modulation of O2 flux (V̇o2) during recovery must be achieved via corresponding changes in effective diffusing capacity (Do2; mainly capillary red blood cell hemodynamics and distribution) in the face of unaltered ΔPo2.NEW & NOTEWORTHY Capillary blood-myocyte O2 flux (V̇o2) is determined by effective diffusing capacity (Do2; mainly erythrocyte hemodynamics and distribution) and microvascular-interstitial Po2 gradients (ΔPo2 = Po2 mv - Po2 is). We show that Po2 is demonstrates on-off asymmetry consistent with Po2 mv and erythrocyte kinetics during metabolic transitions. A substantial transcapillary ΔPo2 was preserved during recovery from contractions, indicative of considerable resistance to O2 diffusion at the microvascular-interstitium interface. This reveals that effective Do2 declines in step with V̇o2 during recovery, as per Fick's law.
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Affiliation(s)
- Daniel M Hirai
- Department of Health and Kinesiology, Purdue University, West Lafayette, Indiana.,Department of Kinesiology, Kansas State University, Manhattan, Kansas.,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Jesse C Craig
- Department of Kinesiology, Kansas State University, Manhattan, Kansas.,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Trenton D Colburn
- Department of Kinesiology, Kansas State University, Manhattan, Kansas.,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Hiroaki Eshima
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Yutaka Kano
- Department of Engineering Science, University of Electro-Communications, Tokyo, Japan
| | - Timothy I Musch
- Department of Kinesiology, Kansas State University, Manhattan, Kansas.,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - David C Poole
- Department of Kinesiology, Kansas State University, Manhattan, Kansas.,Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
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29
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Rosenberry R, Tucker WJ, Haykowsky MJ, Trojacek D, Chamseddine HH, Arena-Marshall CA, Zhu Y, Wang J, Kellawan JM, Tian F, Nelson MD. Determinants of skeletal muscle oxygen consumption assessed by near-infrared diffuse correlation spectroscopy during incremental handgrip exercise. J Appl Physiol (1985) 2019; 127:698-706. [PMID: 31318612 DOI: 10.1152/japplphysiol.00273.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Near-infrared diffuse correlation spectroscopy (DCS) is a rapidly evolving optical imaging technique for the assessment of skeletal muscle O2 utilization (mVO2). We compared DCS-derived determinants of mVO2 with conventional measures [blood flow by brachial artery Doppler ultrasound and venous O2 saturation (SVO2)] in eight volunteers at rest and during incremental handgrip exercise. Brachial artery blood flow and DCS-derived blood flow index (BFI) were linearly related (R2 = 0.57) and increased with each workload, whereas SVO2 decreased from 65.3 ± 2.5% (rest) to 39.9 ± 3.0% (light exercise; P < 0.01) with no change thereafter. In contrast, DCS-derived tissue O2 saturation decreased progressively with each incremental stage (P < 0.01), driven almost entirely by an initial steep rise in deoxyhemoglobin/myoglobin, followed by a linear increase thereafter. Whereas seemingly disparate at first glance, we believe these two approaches provide similar information. Indeed, by plotting the mean convective O2 delivery and diffusive O2 conductance, we show that the initial increase in mVO2 during the transition from rest to exercise was achieved by a greater increase in diffusive O2 conductance versus convective O2 delivery (10-fold vs. 4-fold increase, respectively), explaining the initial decline in SVO2. In contrast, the increase in mVO2 from light to heavy exercise was achieved by equal increases (1.8-fold) in convective O2 delivery and diffusive O2 conductance, explaining the plateau in SVO2. That DCS-derived BFI and deoxyhemoglobin/myoglobin (surrogate measure of O2 extraction) share the same general biphasic pattern suggests that both DCS and conventional approaches provide complementary information regarding the determinants of mVO2.NEW & NOTEWORTHY Near-infrared diffuse correlation spectroscopy (DCS) is an emerging optical imaging technique for quantifying skeletal muscle O2 delivery and utilization at the microvascular level. Here, we show that DCS provides complementary insight into the determinants of muscle O2 consumption across a wide range of exercise intensities, further establishing the utility of DCS.
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Affiliation(s)
- Ryan Rosenberry
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Wesley J Tucker
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.,College of Nursing, University of Texas at Arlington, Arlington, Texas
| | - Mark J Haykowsky
- College of Nursing, University of Texas at Arlington, Arlington, Texas
| | - Darian Trojacek
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Houda H Chamseddine
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | | | - Ye Zhu
- Department of Bioengineering, University of Texas at Arlington, Arlington, Texas
| | - Jing Wang
- College of Nursing, University of Texas at Arlington, Arlington, Texas
| | - J Mikhail Kellawan
- Department of Health and Exercise Science, The University of Oklahoma, Norman, Oklahoma
| | - Fenghua Tian
- Department of Bioengineering, University of Texas at Arlington, Arlington, Texas
| | - Michael D Nelson
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.,Department of Bioengineering, University of Texas at Arlington, Arlington, Texas
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30
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Hendrickse P, Degens H. The role of the microcirculation in muscle function and plasticity. J Muscle Res Cell Motil 2019; 40:127-140. [PMID: 31165949 PMCID: PMC6726668 DOI: 10.1007/s10974-019-09520-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 05/31/2019] [Indexed: 02/07/2023]
Abstract
It is widely acknowledged that maintenance of muscle, size, strength and endurance is necessary for quality of life and the role that skeletal muscle microcirculation plays in muscle health is becoming increasingly clear. Here we discuss the role that skeletal muscle microcirculation plays in muscle function and plasticity. Besides the density of the capillary network, also the distribution of capillaries is crucial for adequate muscle oxygenation. While capillaries are important for oxygen delivery, the capillary supply to a fibre is related to fibre size rather than oxidative capacity. This link between fibre size and capillary supply is also reflected by the similar time course of hypertrophy and angiogenesis, and the cross-talk between capillaries and satellite cells. A dense vascular network may in fact be more important for a swift repair of muscle damage than the abundance of satellite cells and a lower capillary density may also attenuate the hypertrophic response. Capillary rarefaction does not only occur during ageing, but also during conditions as chronic heart failure, where endothelial apoptosis has been reported to precede muscle atrophy. It has been suggested that capillary rarefaction precedes sarcopenia. If so, stimulation of angiogenesis by for instance endurance training before a hypertrophic stimulus may enhance the hypertrophic response. The microcirculation may thus well be a little-explored target to improve muscle function and the success of rehabilitation programmes during ageing and chronic diseases.
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Affiliation(s)
- Paul Hendrickse
- Research Centre for Musculoskeletal Science & Sports Medicine, School of Healthcare Science, Manchester Metropolitan University, John Dalton Building; Chester Street, Manchester, M1 5GD, UK.,Lithuanian Sports University, Kaunas, Lithuania
| | - Hans Degens
- Research Centre for Musculoskeletal Science & Sports Medicine, School of Healthcare Science, Manchester Metropolitan University, John Dalton Building; Chester Street, Manchester, M1 5GD, UK. .,Lithuanian Sports University, Kaunas, Lithuania. .,University of Medicine and Pharmacy of Targu Mures, Targu Mures, Romania.
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31
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Poole DC. Edward F. Adolph Distinguished Lecture. Contemporary model of muscle microcirculation: gateway to function and dysfunction. J Appl Physiol (1985) 2019; 127:1012-1033. [PMID: 31095460 DOI: 10.1152/japplphysiol.00013.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This review strikes at the very heart of how the microcirculation functions to facilitate blood-tissue oxygen, substrate, and metabolite fluxes in skeletal muscle. Contemporary evidence, marshalled from animals and humans using the latest techniques, challenges iconic perspectives that have changed little over the past century. Those perspectives include the following: the presence of contractile or collapsible capillaries in muscle, unitary control by precapillary sphincters, capillary recruitment at the onset of contractions, and the notion of capillary-to-mitochondrial diffusion distances as limiting O2 delivery. Today a wealth of physiological, morphological, and intravital microscopy evidence presents a completely different picture of microcirculatory control. Specifically, capillary red blood cell (RBC) and plasma flux is controlled primarily at the arteriolar level with most capillaries, in healthy muscle, supporting at least some flow at rest. In healthy skeletal muscle, this permits substrate access (whether carried in RBCs or plasma) to a prodigious total capillary surface area. Pathologies such as heart failure or diabetes decrease access to that exchange surface by reducing the proportion of flowing capillaries at rest and during exercise. Capillary morphology and function vary disparately among tissues. The contemporary model of capillary function explains how, following the onset of exercise, muscle O2 uptake kinetics can be extremely fast in health but slowed in heart failure and diabetes impairing contractile function and exercise tolerance. It is argued that adoption of this model is fundamental for understanding microvascular function and dysfunction and, as such, to the design and evaluation of effective therapeutic strategies to improve exercise tolerance and decrease morbidity and mortality in disease.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology, Anatomy and Physiology, Kansas State University, Manhattan, Kansas
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On the Physics Underlying Longitudinal Capillary Recruitment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018. [PMID: 30315546 DOI: 10.1007/978-3-319-96445-4_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Numerous researchers have found that capillary vessel haematocrit depends on the vasodilatory state of the arterioles. At rest, vessel haematocrit is down to 15 %, suggesting a red blood cell velocity three times higher than the plasma velocity. This finding is analysed in the context of present understanding of propulsion of red blood cells (RBCs) and plasma by means of the arteriovenous pressure gradient. Interfacial forces between the red blood cells and the plasma are proposed as a rational explanation of the observed red blood cell velocities. While the arteriovenous pressure gradient across the capillaries propels the red blood cell and the plasma jointly, interfacial forces along the red blood cell membrane can propel RBCs at the cost of the plasma. Different options are explored for the physical origin of these interfacial forces and oxygen gradients are found to be the most probable source.
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Hirai DM, Colburn TD, Craig JC, Hotta K, Kano Y, Musch TI, Poole DC. Skeletal muscle interstitial O 2 pressures: bridging the gap between the capillary and myocyte. Microcirculation 2018; 26:e12497. [PMID: 30120845 DOI: 10.1111/micc.12497] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/26/2018] [Accepted: 08/13/2018] [Indexed: 01/18/2023]
Abstract
The oxygen transport pathway from air to mitochondria involves a series of transfer steps within closely integrated systems (pulmonary, cardiovascular, and tissue metabolic). Small and finite O2 stores in most mammalian species require exquisitely controlled changes in O2 flux rates to support elevated ATP turnover. This is especially true for the contracting skeletal muscle where O2 requirements may increase two orders of magnitude above rest. This brief review focuses on the mechanistic bases for increased microvascular blood-myocyte O2 flux (V̇O2 ) from rest to contractions. Fick's law dictates that V̇O2 elevations driven by muscle contractions are produced by commensurate changes in driving force (ie, O2 pressure gradients; ΔPO2 ) and/or effective diffusing capacity (DO2 ). While previous evidence indicates that increased DO2 helps modulate contracting muscle O2 flux, up until recently the role of the dynamic ΔPO2 across the capillary wall was unknown. Recent phosphorescence quenching investigations of both microvascular and novel interstitial PO2 kinetics in health have resolved an important step in the O2 cascade between the capillary and myocyte. Specifically, the significant transmural ΔPO2 at rest was sustained (but not increased) during submaximal contractions. This supports the contention that the blood-myocyte interface provides a substantial effective resistance to O2 diffusion and underscores that modulations in erythrocyte hemodynamics and distribution (DO2 ) are crucial to preserve the driving force for O2 flux across the capillary wall (ΔPO2 ) during contractions. Investigation of the O2 transport pathway close to muscle mitochondria is key to identifying disease mechanisms and develop therapeutic approaches to ameliorate dysfunction and exercise intolerance.
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Affiliation(s)
- Daniel M Hirai
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - Trenton D Colburn
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - Jesse C Craig
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - Kazuki Hotta
- Department of Engineering Science, University of Electro-Communications, Tokyo, Japan
| | - Yutaka Kano
- Department of Engineering Science, University of Electro-Communications, Tokyo, Japan
| | - Timothy I Musch
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
| | - David C Poole
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, Kansas
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Okerblom J, Fletes W, Patel HH, Schenk S, Varki A, Breen EC. Human-like Cmah inactivation in mice increases running endurance and decreases muscle fatigability: implications for human evolution. Proc Biol Sci 2018; 285:rspb.2018.1656. [PMID: 30209232 PMCID: PMC6158528 DOI: 10.1098/rspb.2018.1656] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 08/20/2018] [Indexed: 12/13/2022] Open
Abstract
Compared to other primates, humans are exceptional long-distance runners, a feature that emerged in genus Homo approximately 2 Ma and is classically attributed to anatomical and physiological adaptations such as an enlarged gluteus maximus and improved heat dissipation. However, no underlying genetic changes have currently been defined. Two to three million years ago, an exon deletion in the CMP-Neu5Ac hydroxylase (CMAH) gene also became fixed in our ancestral lineage. Cmah loss in mice exacerbates disease severity in multiple mouse models for muscular dystrophy, a finding only partially attributed to differences in immune reactivity. We evaluated the exercise capacity of Cmah-/- mice and observed an increased performance during forced treadmill testing and after 15 days of voluntary wheel running. Cmah-/- hindlimb muscle exhibited more capillaries and a greater fatigue resistance in situ Maximal coupled respiration was also higher in Cmah null mice ex vivo and relevant differences in metabolic pathways were also noted. Taken together, these data suggest that CMAH loss contributes to an improved skeletal muscle capacity for oxygen use. If translatable to humans, CMAH loss could have provided a selective advantage for ancestral Homo during the transition from forest dwelling to increased resource exploration and hunter/gatherer behaviour in the open savannah.
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Affiliation(s)
- Jonathan Okerblom
- Center for Academic Research and Training in Anthropogeny (CARTA), University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Glycobiology Research and Training Center (GRTC), University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - William Fletes
- Glycobiology Research and Training Center (GRTC), University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Initiative for Maximizing Student Development (IMSD) Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Hemal H Patel
- Department of Anesthesiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
| | - Simon Schenk
- Department of Orthopedic Surgery, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Ajit Varki
- Center for Academic Research and Training in Anthropogeny (CARTA), University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA .,Glycobiology Research and Training Center (GRTC), University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Ellen C Breen
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Niemeijer VM, Snijders T, Verdijk LB, van Kranenburg J, Groen BBL, Holwerda AM, Spee RF, Wijn PFF, van Loon LJC, Kemps HMC. Skeletal muscle fiber characteristics in patients with chronic heart failure: impact of disease severity and relation with muscle oxygenation during exercise. J Appl Physiol (1985) 2018; 125:1266-1276. [PMID: 30091667 DOI: 10.1152/japplphysiol.00057.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION Skeletal muscle function in patients with heart failure and reduced ejection fraction (HFrEF) greatly determines exercise capacity. However, reports on skeletal muscle fiber dimensions, fiber capillarization, and their physiological importance are inconsistent. METHODS Twenty-five moderately-impaired patients with HFrEF and 25 healthy control (HC) subjects underwent muscle biopsy sampling. Type I and type II muscle fiber characteristics were determined by immunohistochemistry. In patients with HFrEF, enzymatic oxidative capacity was assessed, and pulmonary oxygen uptake (VO2) and skeletal muscle oxygenation during maximal and moderate-intensity exercise were measured using near-infrared spectroscopy. RESULTS While muscle fiber cross-sectional area (CSA) was not different between patients with HFrEF and HC, percentage of type I fibers was higher in HC (46±15% versus 37±12%, respectively, P=0.041). Fiber type distribution and CSA were not different between patients in New York Heart Association (NYHA) class II and III. Type I muscle fiber capillarization was higher in HFrEF compared with controls (capillary-to-fiber perimeter exchange (CFPE) index: 5.70±0.92 versus 5.05±0.82, respectively, P=0.027). Patients in NYHA class III had slower VO2 and muscle deoxygenation kinetics during onset of exercise, and lower muscle oxidative capacity than those in class II (P<0.05). Also, fiber capillarization was lower, but not compared with HC. Higher CFPE index was related to faster deoxygenation (rspearman=-0.682, P=0.001), however, not to muscle oxidative capacity (r=-0.282, P=0.216). CONCLUSIONS Type I muscle fiber capillarization is higher in HFrEF compared with HC, but not in patients with greater exercise impairment. Greater capillarization may positively affect VO2 kinetics by enhancing muscle oxygen diffusion.
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Affiliation(s)
- Victor M Niemeijer
- Department of Cardiology, Máxima Medical Centre, Veldhoven, the Netherlands, Netherlands
| | - Tim Snijders
- Human Movement Sciences, Maastricht University Medical Centre+, Netherlands
| | - Lex B Verdijk
- Human Movement Sciences, Maastricht University Medical Centre, Netherlands
| | - Janneau van Kranenburg
- Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre+ (MUMC+)
| | - Bart B L Groen
- Department of Human Movement Sciences, Maastricht University Medical Centre, Netherlands
| | | | - Ruud F Spee
- Department of Cardiology, Maxima Medical Center, Netherlands
| | - Pieter F F Wijn
- Department of Applied Physics, Eindhoven University of Technology
| | - Luc J C van Loon
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Netherlands
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Van Iterson EH, Smith JR, Olson TP. Exercise on-transition uncoupling of ventilatory, gas exchange and cardiac hemodynamic kinetics accompany pulmonary oxygen stores depletion to impact exercise intolerance in human heart failure. Acta Physiol (Oxf) 2018; 223:e13063. [PMID: 29575588 DOI: 10.1111/apha.13063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/04/2018] [Accepted: 03/08/2018] [Indexed: 12/16/2022]
Abstract
AIM In contrast to knowledge that heart failure (HF) patients demonstrate peak exercise uncoupling across ventilation, gas exchange and cardiac haemodynamics, whether this dyssynchrony follows that at the exercise on-transition is unclear. This study tested whether exercise on-transition temporal lag for ventilation relative to gas exchange and oxygen pulse (O2 pulse) couples with effects from abnormal pulmonary gaseous oxygen store (O2store ) contributions to V˙O2 to interdependently precipitate persistently elevated ventilatory demand and low oxidative metabolic capacity in HF. METHODS Beat-to-beat HR and breath-to-breath ventilation and gas exchange were continuously acquired in HF (N = 9, ejection fraction = 30 ± 9%) and matched controls (N = 10) during square-wave ergometry at 60% V˙O2peak (46 ± 14 vs 125 ± 54-W, P < .001). Temporal responses across V˙E , V˙O2 and O2 pulse were assessed for the exercise on-transition using single exponential model Phase II on-kinetic time constants (τ = time to reach 63% steady-state rise). Breath-to-breath gas fractions and respiratory flows were used to determine O2stores . RESULTS HF vs controls: τ for V˙E (137 ± 93 vs 74 ± 40-seconds, P = .03), V˙O2 (60 ± 40 vs 23 ± 5-seconds, P = .03) and O2 pulse (28 ± 18 vs 23 ± 15-seconds, P = .59). Within HF, τ for V˙E differed from O2 pulse (P < .02), but not V˙O2 . Exercise V˙E rise (workload indexed) differed in HF vs controls (545 ± 139 vs 309 ± 88-mL min-1 W-1 , P < .001). Exercise on-transition O2store depletion in HF exceeded controls, generally persisting to end-exercise. CONCLUSION These data suggest HF demonstrated exercise on-transition O2store depletion (high O2store contribution to V˙O2 ) coupled with dyssynchronous V˙E , V˙O2 and O2 pulse kinetics-not attributable to prolonged cardiac haemodynamics. Persistent high ventilatory demand and low oxidative metabolic capacity in HF may be precipitated by physiological uncoupling occurring within the exercise on-transition.
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Affiliation(s)
- E. H. Van Iterson
- Department of Cardiovascular Medicine; Mayo Clinic; Rochester MN USA
| | - J. R. Smith
- Department of Cardiovascular Medicine; Mayo Clinic; Rochester MN USA
| | - T. P. Olson
- Department of Cardiovascular Medicine; Mayo Clinic; Rochester MN USA
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Golub AS, Dodhy SC, Pittman RN. Oxygen dependence of respiration in rat spinotrapezius muscle contracting at 0.5-8 twitches per second. J Appl Physiol (1985) 2018; 125:124-133. [PMID: 29494286 DOI: 10.1152/japplphysiol.01136.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The oxygen dependence of respiration was obtained in situ in microscopic regions of rat spinotrapezius muscle for different levels of metabolic activity produced by electrical stimulation at rates from 0.5 to 8 Hz. The rate of O2 consumption (V̇o2) was measured with phosphorescence quenching microscopy (PQM) as the rate of O2 disappearance in a muscle with rapid flow arrest. The phosphorescent oxygen probe was loaded into the interstitial space of the muscle to give O2 tension (Po2) in the interstitium. A set of sigmoid curves relating the Po2 dependence of V̇o2 was obtained with a Po2-dependent region below a characteristic Po2 (~30 mmHg) and a Po2-independent region above this Po2. The V̇o2(Po2) plots were fit by the Hill equation containing O2 demand (rest to 8 Hz: 216 ± 26 to 636 ± 77 nl O2/cm3 s) and the Po2 value corresponding to O2 demand/2 (rest to 8 Hz: 22 ± 4 to 11 ± 1 mmHg). The initial Po2 and V̇o2 pairs of values measured at the moment of flow arrest formed a straight line, determining the rate of oxygen supply. This line had a negative slope, equal to the oxygen conductance for the O2 supply chain. For each level of tissue blood flow the set of possible values of Po2 and V̇o2 consists of the intersection points between this O2 supply line and the set of V̇o2 curves. An electrical analogy for the intraorgan O2 supply and consumption is an inverting transistor amplifier, which allows the use of graphic analysis methods for prediction of the behavior of the oxygen processing system in organs. NEW & NOTEWORTHY The sigmoidal shape of curves describing oxygen dependence of muscle respiration varies from basal to maximal workload and characterizes the oxidative metabolism of muscle. The rate of O2 supply depends on extracellular O2 tension and is determined by the overall oxygen conductance in the muscle. The dynamics of oxygen consumption is determined by the supply line that intersects the oxygen demand curves. An electrical analogy for the oxygen supply/consumption system is an inverting transistor amplifier.
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Affiliation(s)
- Aleksander S Golub
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia
| | - Sami C Dodhy
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia
| | - Roland N Pittman
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia
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Almohanna AM, Wray S. Hypoxic conditioning in blood vessels and smooth muscle tissues: effects on function, mechanisms, and unknowns. Am J Physiol Heart Circ Physiol 2018; 315:H756-H770. [PMID: 29702009 DOI: 10.1152/ajpheart.00725.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hypoxic preconditioning, the protective effect of brief, intermittent hypoxic or ischemic episodes on subsequent more severe hypoxic episodes, has been known for 30 yr from studies on cardiac muscle. The concept of hypoxic preconditioning has expanded; excitingly, organs beyond the heart, including the brain, liver, and kidney, also benefit. Preconditioning of vascular and visceral smooth muscles has received less attention despite their obvious importance to health. In addition, there has been no attempt to synthesize the literature in this field. Therefore, in addition to overviewing the current understanding of hypoxic conditioning, in the present review, we consider the role of blood vessels in conditioning and explore evidence for conditioning in other smooth muscles. Where possible, we have distinguished effects on myocytes from other cell types in the visceral organs. We found evidence of a pivotal role for blood vessels in conditioning and for conditioning in other smooth muscle, including the bladder, vascular myocytes, and gastrointestinal tract, and a novel response in the uterus of a hypoxic-induced force increase, which helps maintain contractions during labor. To date, however, there are insufficient data to provide a comprehensive or unifying mechanism for smooth muscles or visceral organs and the effects of conditioning on their function. This also means that no firm conclusions can be drawn as to how differences between smooth muscles in metabolic and contractile activity may contribute to conditioning. Therefore, we have suggested what may be general mechanisms of conditioning occurring in all smooth muscles and tabulated tissue-specific mechanistic findings and suggested ideas for further progress.
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Affiliation(s)
- Asmaa M Almohanna
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine University of Liverpool , Liverpool , United Kingdom.,Princess Nourah bint Abdulrahman University , Riyadh , Saudi Arabia
| | - Susan Wray
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine University of Liverpool , Liverpool , United Kingdom
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Hirai DM, Craig JC, Colburn TD, Eshima H, Kano Y, Sexton WL, Musch TI, Poole DC. Skeletal muscle microvascular and interstitial PO2 from rest to contractions. J Physiol 2018; 596:869-883. [PMID: 29288568 DOI: 10.1113/jp275170] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 12/01/2017] [Indexed: 01/21/2023] Open
Abstract
KEY POINTS Oxygen pressure gradients across the microvascular walls are essential for oxygen diffusion from blood to tissue cells. At any given flux, the magnitude of these transmural gradients is proportional to the local resistance. The greatest resistance to oxygen transport into skeletal muscle is considered to reside in the short distance between red blood cells and myocytes. Although crucial to oxygen transport, little is known about transmural pressure gradients within skeletal muscle during contractions. We evaluated oxygen pressures within both the skeletal muscle microvascular and interstitial spaces to determine transmural gradients during the rest-contraction transient in anaesthetized rats. The significant transmural gradient observed at rest was sustained during submaximal muscle contractions. Our findings support that the blood-myocyte interface provides substantial resistance to oxygen diffusion at rest and during contractions and suggest that modulations in microvascular haemodynamics and red blood cell distribution constitute primary mechanisms driving increased transmural oxygen flux with contractions. ABSTRACT Oxygen pressure (PO2) gradients across the blood-myocyte interface are required for diffusive O2 transport, thereby supporting oxidative metabolism. The greatest resistance to O2 flux into skeletal muscle is considered to reside between the erythrocyte surface and adjacent sarcolemma, although this has not been measured during contractions. We tested the hypothesis that O2 gradients between skeletal muscle microvascular (PO2 mv ) and interstitial (PO2 is ) spaces would be present at rest and maintained or increased during contractions. PO2 mv and PO2 is were determined via phosphorescence quenching (Oxyphor probes G2 and G4, respectively) in the exposed rat spinotrapezius during the rest-contraction transient (1 Hz, 6 V; n = 8). PO2 mv was higher than PO2 is in all instances from rest (34.9 ± 6.0 versus 15.7 ± 6.4) to contractions (28.4 ± 5.3 versus 10.6 ± 5.2 mmHg, respectively) such that the mean PO2 gradient throughout the transient was 16.9 ± 6.6 mmHg (P < 0.05 for all). No differences in the amplitude of PO2 fall with contractions were observed between the microvasculature and interstitium (10.9 ± 2.3 versus 9.0 ± 3.5 mmHg, respectively; P > 0.05). However, the speed of the PO2 is fall during contractions was slower than that of PO2 mv (time constant: 12.8 ± 4.7 versus 9.0 ± 5.1 s, respectively; P < 0.05). Consistent with our hypothesis, a significant transmural gradient was sustained (but not increased) from rest to contractions. This supports that the blood-myocyte interface is the site of a substantial PO2 gradient driving O2 diffusion during metabolic transients. Based on Fick's law, elevated O2 flux with contractions must thus rely primarily on modulations in effective diffusing capacity (mainly erythrocyte haemodynamics and distribution) as the PO2 gradient is not increased.
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Affiliation(s)
- Daniel M Hirai
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Jesse C Craig
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Trenton D Colburn
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Hiroaki Eshima
- Department of Engineering Science, University of Electro-Communications, Tokyo, Japan
| | - Yutaka Kano
- Department of Engineering Science, University of Electro-Communications, Tokyo, Japan
| | - William L Sexton
- Department of Physiology, A.T. Still University of Health Sciences, Kirksville, MO, USA
| | - Timothy I Musch
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, KS, USA
| | - David C Poole
- Departments of Anatomy & Physiology, Kinesiology, Kansas State University, Manhattan, KS, USA
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Domínguez R, Maté-Muñoz JL, Cuenca E, García-Fernández P, Mata-Ordoñez F, Lozano-Estevan MC, Veiga-Herreros P, da Silva SF, Garnacho-Castaño MV. Effects of beetroot juice supplementation on intermittent high-intensity exercise efforts. J Int Soc Sports Nutr 2018; 15:2. [PMID: 29311764 PMCID: PMC5756374 DOI: 10.1186/s12970-017-0204-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 12/07/2017] [Indexed: 12/21/2022] Open
Abstract
Beetroot juice contains high levels of inorganic nitrate (NO3-) and its intake has proved effective at increasing blood nitric oxide (NO) concentrations. Given the effects of NO in promoting vasodilation and blood flow with beneficial impacts on muscle contraction, several studies have detected an ergogenic effect of beetroot juice supplementation on exercise efforts with high oxidative energy metabolism demands. However, only a scarce yet growing number of investigations have sought to assess the effects of this supplement on performance at high-intensity exercise. Here we review the few studies that have addressed this issue. The databases Dialnet, Elsevier, Medline, Pubmed and Web of Science were searched for articles in English, Portuguese and Spanish published from 2010 to March 31 to 2017 using the keywords: beet or beetroot or nitrate or nitrite and supplement or supplementation or nutrition or "sport nutrition" and exercise or sport or "physical activity" or effort or athlete. Nine articles fulfilling the inclusion criteria were identified. Results indicate that beetroot juice given as a single dose or over a few days may improve performance at intermittent, high-intensity efforts with short rest periods. The improvements observed were attributed to faster phosphocreatine resynthesis which could delay its depletion during repetitive exercise efforts. In addition, beetroot juice supplementation could improve muscle power output via a mechanism involving a faster muscle shortening velocity. The findings of some studies also suggested improved indicators of muscular fatigue, though the mechanism involved in this effect remains unclear.
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Affiliation(s)
- Raúl Domínguez
- Physical Activity and Sport Sciences, College of Health Sciences, Alfonso X El Sabio University, Madrid, Spain
| | - José Luis Maté-Muñoz
- Physical Activity and Sport Sciences, College of Health Sciences, Alfonso X El Sabio University, Madrid, Spain
| | - Eduardo Cuenca
- TecnoCampus. GRI-AFIRS, School of Health Sciences, Pompeu Fabra University, Mataró, Barcelona, Spain
| | - Pablo García-Fernández
- Physical Activity and Sport Sciences, College of Health Sciences, Alfonso X El Sabio University, Madrid, Spain
| | | | - María Carmen Lozano-Estevan
- Physical Activity and Sport Sciences, College of Health Sciences, Alfonso X El Sabio University, Madrid, Spain
| | - Pablo Veiga-Herreros
- Physical Activity and Sport Sciences, College of Health Sciences, Alfonso X El Sabio University, Madrid, Spain
| | - Sandro Fernandes da Silva
- Physical Activity and Sport Sciences, Physical Education Departament, University of Lavras, Lavras, Brazil
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Place TL, Domann FE, Case AJ. Limitations of oxygen delivery to cells in culture: An underappreciated problem in basic and translational research. Free Radic Biol Med 2017; 113:311-322. [PMID: 29032224 PMCID: PMC5699948 DOI: 10.1016/j.freeradbiomed.2017.10.003] [Citation(s) in RCA: 240] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 10/02/2017] [Accepted: 10/04/2017] [Indexed: 01/08/2023]
Abstract
Molecular oxygen is one of the most important variables in modern cell culture systems. Fluctuations in its concentration can affect cell growth, differentiation, signaling, and free radical production. In order to maintain culture viability, experimental validity, and reproducibility, it is imperative that oxygen levels be consistently maintained within physiological "normoxic" limits. Use of the term normoxia, however, is not consistent among scientists who experiment in cell culture. It is typically used to describe the atmospheric conditions of a standard incubator, not the true microenvironment to which the cells are exposed. This error may lead to the situation where cells grown in a standard "normoxic" oxygen concentration may actually be experiencing a wide range of conditions ranging from hyperoxia to near-anoxic conditions at the cellular level. This apparent paradox is created by oxygen's sluggish rate of diffusion through aqueous medium, and the generally underappreciated effects that cell density, media volume, and barometric pressure can have on pericellular oxygen concentration in a cell culture system. This review aims to provide an overview of this phenomenon we have termed "consumptive oxygen depletion" (COD), and includes a basic review of the physics, potential consequences, and alternative culture methods currently available to help circumvent this largely unrecognized problem.
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Affiliation(s)
- Trenton L. Place
- Department of Obstetrics & Gynecology, Carver College of Medicine, The University of Iowa, Iowa City, IA
| | - Frederick E. Domann
- Department of Radiation Oncology, Carver College of Medicine, The University of Iowa, Iowa City, IA
- Department of Pathology, Carver College of Medicine, The University of Iowa, Iowa City, IA
- Department of Surgery, Carver College of Medicine, The University of Iowa, Iowa City, IA
- Corresponding authors: Department of Physiology, University of Nebraska Medical Center, Omaha, NE 68198.
| | - Adam J. Case
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE
- Corresponding authors: Department of Physiology, University of Nebraska Medical Center, Omaha, NE 68198.
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Evidence of a metabolic reserve in the skeletal muscle of elderly people. Aging (Albany NY) 2017; 9:52-67. [PMID: 27824313 PMCID: PMC5310656 DOI: 10.18632/aging.101079] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/20/2016] [Indexed: 11/25/2022]
Abstract
The purpose of the present study was to determine whether mitochondrial function is limited by O2 availability or the intrinsic capacity of mitochondria to synthesize ATP in elderly individuals. To this aim, we examined, in comparison to free-flow conditions (FF), the effect of superimposing reactive hyperemia (RH), induced by a period of brief ischemia during the last min of exercise, on O2 availability and mitochondrial function in the calf muscle. 12 healthy, untrained, elderly subjects performed dynamic plantar flexion exercise and phosphorus magnetic resonance spectroscopy (31P-MRS), near-infrared spectroscopy (NIRS), and Doppler ultrasound were used to assess muscle metabolism and peripheral hemodynamics. Limb blood flow [area under the curve (AUC), FF: 1.5±0.5L; RH: 3.2±1.1L, P<0.01] and convective O2 delivery (AUC, FF: 0.30±0.13L; RH: 0.64±0.29L, P<0.01) were significantly increased in RH in comparison to FF. RH was also associated with significantly higher capillary blood flow (P<0.05) and this resulted in a 33% increase in estimated peak mitochondrial ATP synthesis rate (FF: 24±11 mM.min−1; RH: 31±7 mM.min−1, P<0.05). These results document a hemodynamic reserve in the contracting calf muscle of the elderly accessible by superimposing reactive hyperemia. Furthermore, this increase in O2 availability enhanced mitochondrial function thus indicating a skeletal muscle metabolic reserve despite advancing age and low level of physical activity.
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Watanabe A, Poole DC, Kano Y. The effects of RSR13 on microvascular Po2 kinetics and muscle contractile performance in the rat arterial ligation model of peripheral arterial disease. J Appl Physiol (1985) 2017; 123:764-772. [DOI: 10.1152/japplphysiol.00257.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/17/2017] [Accepted: 06/08/2017] [Indexed: 01/12/2023] Open
Abstract
Exercise intolerance and claudication are symptomatic of peripheral arterial disease. There is a close relationship between muscle O2 delivery, microvascular oxygen partial pressure (P mvO2), and contractile performance. We therefore hypothesized that a reduction of hemoglobin-oxygen affinity via RSR13 would maintain a higher P mvO2 and enhance blood-muscle O2 transport and contractile function. In male Wistar rats (12 wk of age), we created hindlimb ischemia via right-side iliac artery ligation (AL). The contralateral (left) muscle served as control (CONT). Seven days after AL, phosphorescence-quenching techniques were used to measure P mvO2 at rest and during contractions (electrical stimulation; 1 Hz, 300 s) in tibialis anterior muscle (TA) under saline ( n = 10) or RSR13 ( n = 10) conditions. RSR13 at rest increased TA P mvO2 in CONT (13.9 ± 1.6 to 19.3 ± 1.9 Torr, P < 0.05) and AL (9.0 ± 0.5 to 9.9 ± 0.7 Torr, P < 0.05). Furthermore, RSR13 extended maintenance of the initial TA force (i.e., improved contractile performance) such that force was not decreased significantly until contraction 240 vs. 150 in CONT and 80 vs. 20 in AL. This improved muscle endurance with RSR13 was accompanied by a greater ΔP mvO2 (P mvO2 decrease from baseline) (CONT, 7.4 ± 1.0 to 11.2 ± 1.3; AL, 6.9 ± 0.5 to 8.6 ± 0.6 Torr, both P < 0.05). Whereas RSR13 did not alter the kinetics profile of P mvO2 (i.e., mean response time) substantially during contractions, muscle force was elevated, and the ratio of muscle force to P mvO2 increased. In conclusion, reduction of hemoglobin-oxygen affinity via RSR13 in AL increased P mvO2 and improved muscle contractile performance most likely via enhanced blood-muscle O2 diffusion. NEW & NOTEWORTHY This is the first investigation to examine the effect of RSR13 (erythrocyte allosteric effector) on skeletal muscle microvascular oxygen partial pressure kinetics and contractile function using an arterial ligation model of peripheral arterial disease in experimental animals. The present results provide strong support for the concept that reducing hemoglobin-O2 affinity via RSR13 improved tibialis anterior muscle contractile performance most likely via enhanced blood-muscle O2 diffusion.
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Affiliation(s)
- Aiko Watanabe
- Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo, Japan; and
| | - David C. Poole
- Departments of Anatomy, Physiology and Kinesiology, Kansas State University, Manhattan, KS
| | - Yutaka Kano
- Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo, Japan; and
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Cardiovascular Responses to Skeletal Muscle Stretching: “Stretching” the Truth or a New Exercise Paradigm for Cardiovascular Medicine? Sports Med 2017; 47:2507-2520. [DOI: 10.1007/s40279-017-0768-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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45
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Hirai DM, Jones JH, Zelt JT, da Silva ML, Bentley RF, Edgett BA, Gurd BJ, Tschakovsky ME, O'Donnell DE, Neder JA. Oral N-acetylcysteine and exercise tolerance in mild chronic obstructive pulmonary disease. J Appl Physiol (1985) 2017; 122:1351-1361. [PMID: 28255088 DOI: 10.1152/japplphysiol.00990.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 01/25/2023] Open
Abstract
Heightened oxidative stress is implicated in the progressive impairment of skeletal muscle vascular and mitochondrial function in chronic obstructive pulmonary disease (COPD). Whether accumulation of reactive oxygen species contributes to exercise intolerance in the early stages of COPD is unknown. The purpose of the present study was to determine the effects of oral antioxidant treatment with N-acetylcysteine (NAC) on respiratory, cardiovascular, and locomotor muscle function and exercise tolerance in patients with mild COPD. Thirteen patients [forced expiratory volume in 1 s (FEV1)-to-forced vital capacity ratio < lower limit of normal (LLN) and FEV1 ≥ LLN) were enrolled in a double-blind, randomized crossover study to receive NAC (1,800 mg/day) or placebo for 4 days. Severe-intensity constant-load exercise tests were performed with noninvasive measurements of central hemodynamics (stroke volume, heart rate, and cardiac output via impedance cardiography), arterial blood pressure, pulmonary ventilation and gas exchange, quadriceps muscle oxygenation (near-infrared spectroscopy), and estimated capillary blood flow. Nine patients completed the study with no major adverse clinical effects. Although NAC elevated plasma glutathione by ~27% compared with placebo (P < 0.05), there were no differences in exercise tolerance (placebo: 325 ± 47 s, NAC: 336 ± 51 s), central hemodynamics, arterial blood pressure, pulmonary ventilation or gas exchange, locomotor muscle oxygenation, or capillary blood flow from rest to exercise between conditions (P > 0.05 for all). In conclusion, modulation of plasma redox status with oral NAC treatment was not translated into beneficial effects on central or peripheral components of the oxygen transport pathway, thereby failing to improve exercise tolerance in nonhypoxemic patients with mild COPD.NEW & NOTEWORTHY Acute antioxidant treatment with N-acetylcysteine (NAC) elevated plasma glutathione but did not modulate central or peripheral components of the O2 transport pathway, thereby failing to improve exercise tolerance in patients with mild chronic obstructive pulmonary disease (COPD).
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Affiliation(s)
- Daniel M Hirai
- Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada; .,Pulmonary Function and Clinical Exercise Physiology Unit, Respiratory Division, Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Joshua H Jones
- Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Joel T Zelt
- Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Marianne L da Silva
- Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada.,Division of Physical Therapy, University of Brasilia, Brasilia, Brazil
| | - Robert F Bentley
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Brittany A Edgett
- Queen's Muscle Physiology Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada; and
| | - Brendon J Gurd
- Queen's Muscle Physiology Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada; and
| | - Michael E Tschakovsky
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - J Alberto Neder
- Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
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Niemeijer VM, Jansen JP, van Dijk T, Spee RF, Meijer EJ, Kemps HMC, Wijn PFF. The influence of adipose tissue on spatially resolved near-infrared spectroscopy derived skeletal muscle oxygenation: the extent of the problem. Physiol Meas 2017; 38:539-554. [PMID: 28151429 DOI: 10.1088/1361-6579/aa5dd5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Near-infrared spectroscopy (NIRS) measurements of tissue oxygen saturation (StO2) are useful for the assessment of skeletal muscle perfusion and function during exercise, however, they are influenced by overlying skin and adipose tissue. This study explored the extent and nature of the influence of adipose tissue thickness (ATT) on StO2. APPROACH NIR spatially resolved spectroscopy (SRS) derived oxygenation was measured on vastus lateralis in 56 patients with chronic heart failure (CHF) and 20 healthy control (HC) subjects during rest and moderate intensity exercise with simultaneous assessment of oxygen uptake kinetics (τ [Formula: see text]). In vitro measurements were performed on a flow cell with a blood mixture with full oxygen saturation (100%), which was gradually decreased to 0% by adding sodium metabisulfite. Experiments were repeated with 2 mm increments of porcine fat layer between the NIRS device and flow cell up to 14 mm. MAIN RESULTS Lower ATT, higher τ [Formula: see text], and CHF were independently associated with lower in vivo StO2 in multiple regression analysis, whereas age and gender showed no independent relationship. With greater ATT, in vitro StO2 was reduced from 100% to 74% for fully oxygenated blood and increased from 0% to 68% for deoxygenated blood. SIGNIFICANCE This study shows that ATT independently confounds NIR-SRS derived StO2 by overestimating actual skeletal muscle oxygenation and by decreasing its sensitivity for deoxygenation. Because physiological properties (e.g. presence of disease and slowing of τ [Formula: see text]) also influence NIR-SRS, a correction based on optical properties is needed to interpret calculated values as absolute StO2.
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Affiliation(s)
- Victor M Niemeijer
- Department of Cardiology, Máxima Medical Centre, PO Box 7777, 5500 MB Veldhoven, Netherlands. Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, Netherlands
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Ade CJ, Broxterman RM, Barstow TJ. VO(2max) and Microgravity Exposure: Convective versus Diffusive O(2) Transport. Med Sci Sports Exerc 2016; 47:1351-61. [PMID: 25380479 DOI: 10.1249/mss.0000000000000557] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Exposure to a microgravity environment decreases the maximal rate of O2 uptake (VO(2max)) in healthy individuals returning to a gravitational environment. The magnitude of this decrease in VO(2max) is, in part, dependent on the duration of microgravity exposure, such that long exposure may result in up to a 38% decrease in VO(2max). This review identifies the components within the O(2) transport pathway that determine the decrease in postmicrogravity VO(2max) and highlights the potential contributing physiological mechanisms. A retrospective analysis revealed that the decline in VO(2max) is initially mediated by a decrease in convective and diffusive O(2) transport that occurs as the duration of microgravity exposure is extended. Mechanistically, the attenuation of O(2) transport is the combined result of a deconditioning across multiple organ systems including decreases in total blood volume, red blood cell mass, cardiac function and mass, vascular function, skeletal muscle mass, and, potentially, capillary hemodynamics, which become evident during exercise upon re-exposure to the head-to-foot gravitational forces of upright posture on Earth. In summary, VO(2max) is determined by the integration of central and peripheral O(2) transport mechanisms, which, if not maintained during microgravity, will have a substantial long-term detrimental impact on space mission performance and astronaut health.
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Affiliation(s)
- Carl J Ade
- 1Department of Health and Exercise Science, University of Oklahoma, Norman, OK; 2Department of Kinesiology, Kansas State University, Manhattan, KS; and 3Department of Anatomy and Physiology, Kansas State University, Manhattan, KS
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Ellsworth ML, Ellis CG, Sprague RS. Role of erythrocyte-released ATP in the regulation of microvascular oxygen supply in skeletal muscle. Acta Physiol (Oxf) 2016; 216:265-76. [PMID: 26336065 DOI: 10.1111/apha.12596] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 05/18/2015] [Accepted: 08/28/2015] [Indexed: 12/23/2022]
Abstract
In a 1914 book entitled The Respiratory Function of the Blood, Joseph Barcroft stated that 'the cell takes what it needs and leaves the rest'. He postulated that there must be both a 'call for oxygen' and a 'mechanism by which the call elicits a response...' In the past century, intensive investigation has provided significant insights into the haemodynamic and biophysical mechanisms involved in supplying oxygen to skeletal muscle. However, the identification of the mechanism by which tissue oxygen needs are sensed and the affector responsible for altering the upstream vasculature to enable the need to be appropriately met has been a challenge. In 1995, Ellsworth et al. proposed that the oxygen-carrying erythrocyte, by virtue of its capacity to release the vasoactive mediator ATP in response to a decrease in oxygen saturation, could serve both roles. Several in vitro and in situ studies have established that exposure of erythrocytes to reduced oxygen tension induces the release of ATP which does result in a conducted arteriolar vasodilation with a sufficiently rapid time course to make the mechanism physiologically relevant. The components of the signalling pathway for the controlled release of ATP from erythrocytes in response to exposure to low oxygen tension have been determined. In addition, the implications of defective ATP release on human pathological conditions have been explored. This review provides a perspective on oxygen supply and the role that such a mechanism plays in meeting the oxygen needs of skeletal muscle.
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Affiliation(s)
- M. L. Ellsworth
- Department of Pharmacological and Physiological Science; Saint Louis University School of Medicine; St. Louis MO USA
| | - C. G. Ellis
- Departments of Medical Biophysics and Medicine; Schulich School of Medicine & Dentistry; The University of Western Ontario; London ON Canada
| | - R. S. Sprague
- Department of Pharmacological and Physiological Science; Saint Louis University School of Medicine; St. Louis MO USA
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McKeever KH, McNally BA, Hinchcliff KW, Lehnhard RA, Poole DC. Effects of erythropoietin on systemic hematocrit and oxygen transport in the splenectomized horse. Respir Physiol Neurobiol 2016; 225:38-47. [PMID: 26853328 DOI: 10.1016/j.resp.2016.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 01/30/2016] [Accepted: 02/02/2016] [Indexed: 11/16/2022]
Abstract
To test the hypotheses that erythropoietin (rhuEPO) treatment increases systemic hematocrit, maximal O2 uptake (VO2max, by elevated perfusive and diffusive O2 conductances) and performance five female horses (4-13 years) received 15 IU/kg rhuEPO (erythropoietin) three times per week for three weeks. These horses had been splenectomized over 1 year previously to avoid confounding effects from the mobilization of splenic red blood cell reserves. Each horse performed three maximal exercise tests (one per month) on an inclined (4°) treadmill to the limit of tolerance; two control trials and one following EPO treatment. Measurements of hemoglobin concentration ([Hb] and hematocrit), plasma and blood volume, VO2, cardiac output as well as arterial and mixed venous blood gases were made at rest and during maximal exercise. EPO increased resting [Hb] by 18% from 13.3 ± 0.6 to 15.7 ± 0.8 g/dL (mean ± SD) corresponding to an increased hematocrit from 36 ± 2 to 46 ± 2% concurrent with 23 and 10% reductions in plasma and blood volume, respectively (all P<0.05). EPO elevated VO2max by 20% from 25.7 ± 1.7 to 30.9 ± 3.4 L/min (P<0.05) via a 17% increase in arterial O2 content and 18% greater arteriovenous O2 difference in the face of an unchanged cardiac output. To achieve the greater VO2max after EPO, diffusive O2 conductance increased ∼ 30% (from 580 ± 76 to 752 ± 166 mL O2/mmHg/min, P<0.05) which was substantially greater than the elevation of perfusive O2 conductance. These effects of EPO were associated with an increased exercise performance (total running time: control, 216 ± 72; EPO, 264 ± 48 s, P<0.05). We conclude that EPO substantially increases VO2max and performance in the splenectomized horse via improved perfusive and diffusive O2 transport.
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Affiliation(s)
- Kenneth H McKeever
- Department of Animal Science, Rutgers the State University of New Jersey, New Brunswick, NJ 08903, United States.
| | - Beth A McNally
- School of Health, Physical Education and Recreation, The Ohio State University, Columbus, OH 43210, United States
| | - Kenneth W Hinchcliff
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, Australia
| | - Robert A Lehnhard
- Department of Kinesiology, University of Maine, Orono, ME, United States
| | - David C Poole
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, United States
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50
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Ederer AK, Didier KD, Reiter LK, Brown M, Hardy R, Caldwell J, Black CD, Larson RD, Ade CJ. Influence of Adjuvant Therapy in Cancer Survivors on Endothelial Function and Skeletal Muscle Deoxygenation. PLoS One 2016; 11:e0147691. [PMID: 26807572 PMCID: PMC4726690 DOI: 10.1371/journal.pone.0147691] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 01/07/2016] [Indexed: 12/16/2022] Open
Abstract
The cardiotoxic effects of adjuvant cancer treatments (i.e., chemotherapy and radiation treatment) have been well documented, but the effects on peripheral cardiovascular function are still unclear. We hypothesized that cancer survivors i) would have decreased resting endothelial function; and ii) altered muscle deoxygenation response during moderate intensity cycling exercise compared to cancer-free controls. A total of 8 cancer survivors (~70 months post-treatment) and 9 healthy controls completed a brachial artery FMD test, an index of endothelial-dependent dilation, followed by an incremental exercise test up to the ventilatory threshold (VT) on a cycle ergometer during which pulmonary V˙O2 and changes in near-infrared spectroscopy (NIRS)-derived microvascular tissue oxygenation (TOI), total hemoglobin concentration ([Hb]total), and muscle deoxygenation ([HHb] ≈ fractional O2 extraction) were measured. There were no significant differences in age, height, weight, and resting blood pressure between cancer survivors and control participants. Brachial artery FMD was similar between groups (P = 0.98). During exercise at the VT, TOI was similar between groups, but [Hb]total and [HHb] were significantly decreased in cancer survivors compared to controls (P < 0.01) The rate of change for TOI (ΔTOIΔ/V˙O2) and [HHb] (Δ[HHb]/ΔV˙O2) relative to ΔV˙O2 were decreased in cancer survivors compared to controls (P = 0.02 and P = 0.03 respectively). In cancer survivors, a decreased skeletal muscle microvascular function was observed during moderate intensity cycling exercise. These data suggest that adjuvant cancer therapies have an effect on the integrated relationship between O2 extraction, V˙O2 and O2 delivery during exercise.
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Affiliation(s)
- Austin K. Ederer
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Kaylin D. Didier
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Landon K. Reiter
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Michael Brown
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Rachel Hardy
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Jacob Caldwell
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Christopher D. Black
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Rebecca D. Larson
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
| | - Carl J. Ade
- Department of Health and Exercise Science, The University of Oklahoma, Norman, OK, United States of America
- * E-mail:
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