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He Y, Yang W, Huang L, Mever MA, Ramautar R, Harms A, Rijksen Y, Brandt RM, Barnhoorn S, Smit K, Jaarsma D, Lindenburg P, Hoeijmakers JHJ, Vermeij WP, Hankemeier T. Metabolomic analysis of dietary-restriction-induced attenuation of sarcopenia in prematurely aging DNA repair-deficient mice. J Cachexia Sarcopenia Muscle 2024; 15:868-882. [PMID: 38689513 PMCID: PMC11154776 DOI: 10.1002/jcsm.13433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 12/17/2023] [Accepted: 12/20/2023] [Indexed: 05/02/2024] Open
Abstract
BACKGROUND Sarcopenia is characterized by loss of skeletal muscle mass and function, and is a major risk factor for disability and independence in the elderly. Effective medication is not available. Dietary restriction (DR) has been found to attenuate aging and aging-related diseases, including sarcopenia, but the mechanism of both DR and sarcopenia are incompletely understood. METHODS In this study, mice body weight, fore and all limb grip strength, and motor learning and coordination performance were first analysed to evaluate the DR effects on muscle functioning. Liquid chromatography-mass spectrometry (LC-MS) was utilized for the metabolomics study of the DR effects on sarcopenia in progeroid DNA repair-deficient Ercc1∆/- and Xpg-/- mice, to identify potential biomarkers for attenuation of sarcopenia. RESULTS Muscle mass was significantly (P < 0.05) decreased (13-20%) by DR; however, the muscle quality was improved with retained fore limbs and all limbs grip strength in Ercc1∆/- and Xpg-/- mice. The LC-MS results revealed that metabolites and pathways related to oxidative-stress, that is, GSSG/GSH (P < 0.01); inflammation, that is, 9-HODE, 11-HETE (P < 0.05), PGE2, PGD2, and TXB2 (P < 0.01); and muscle growth (PGF2α) (P < 0.01) and regeneration stimulation (PGE2) (P < 0.05) are significantly downregulated by DR. On the other hand, anti-inflammatory indicator and several related metabolites, that is, β-hydroxybutyrate (P < 0.01), 14,15-DiHETE (P < 0.0001), 8,9-EET, 12,13-DiHODE, and PGF1 (P < 0.05); consumption of sources of energy (i.e., muscle and liver glycogen); and energy production pathways, that is, glycolysis (glucose, glucose-6-P, fructose-6-P) (P < 0.01), tricarboxylic acid cycle (succinyl-CoA, malate) (P < 0.001), and gluconeogenesis-related metabolite, alanine (P < 0.01), are significantly upregulated by DR. The notably (P < 0.01) down-modulated muscle growth (PGF2α) and regeneration (PGE2) stimulation metabolite and the increased consumption of glycogen in muscle and liver may be related to the significantly (P < 0.01) lower body weight and muscle mass by DR. The downregulated oxidative stress, pro-inflammatory mediators, and upregulated anti-inflammatory metabolites resulted in a lower energy expenditure, which contributed to enhanced muscle quality together with upregulated energy production pathways by DR. The improved muscle quality may explain why grip strength is maintained and motor coordination and learning performance are improved by DR in Ercc1∆/- and Xpg-/- mice. CONCLUSIONS This study provides fundamental supporting information on biomarkers and pathways related to the attenuation of sarcopenia, which might facilitate its diagnosis, prevention, and clinical therapy.
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Affiliation(s)
- Yupeng He
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
| | - Wei Yang
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
| | - Luojiao Huang
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
| | - Marlien Admiraal‐van Mever
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
| | - Rawi Ramautar
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
| | - Amy Harms
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
| | - Yvonne Rijksen
- Princess Máxima Center for Pediatric OncologyUtrechtThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
| | - Renata M.C. Brandt
- Department of Molecular Genetics, Erasmus MC Cancer InstituteErasmus University Medical Center RotterdamRotterdamThe Netherlands
| | - Sander Barnhoorn
- Department of Molecular Genetics, Erasmus MC Cancer InstituteErasmus University Medical Center RotterdamRotterdamThe Netherlands
| | - Kimberly Smit
- Princess Máxima Center for Pediatric OncologyUtrechtThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
| | - Dick Jaarsma
- Department of NeuroscienceErasmus University Medical Center RotterdamRotterdamThe Netherlands
| | - Peter Lindenburg
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
- Research Group Metabolomics, Leiden Center for Applied BioscienceUniversity of Applied Sciences LeidenLeidenThe Netherlands
| | - Jan H. J. Hoeijmakers
- Princess Máxima Center for Pediatric OncologyUtrechtThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
- Department of Molecular Genetics, Erasmus MC Cancer InstituteErasmus University Medical Center RotterdamRotterdamThe Netherlands
- Institute for Genome Stability in Aging and Disease, Cologne Excellence Cluster for Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Wilbert P. Vermeij
- Princess Máxima Center for Pediatric OncologyUtrechtThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
| | - Thomas Hankemeier
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug ResearchLeiden UniversityLeidenThe Netherlands
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2
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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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3
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Leo JA, Sabapathy S, Kuck L, Simmonds MJ. Modulation of red blood cell nitric oxide synthase phosphorylation in the quiescent and exercising human forearm. Am J Physiol Regul Integr Comp Physiol 2023; 325:R260-R268. [PMID: 37424398 DOI: 10.1152/ajpregu.00017.2023] [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: 01/17/2023] [Revised: 06/14/2023] [Accepted: 07/03/2023] [Indexed: 07/11/2023]
Abstract
In vitro investigations demonstrate that human erythrocytes synthesize nitric oxide via a functional isoform of endothelial nitric oxide synthase (NOS) (RBC-NOS). We tested the hypothesis that phosphorylation of RBC-NOS at serine residue 1177 (RBC-NOS1177) would be amplified in blood draining-active skeletal muscle. Furthermore, given hypoxemia modulates local blood flow and thus shear stress, and nitric oxide availability, we performed duplicate experiments under normoxia and hypoxia. Nine healthy volunteers performed rhythmic handgrip exercise at 60% of individualized maximal workload for 3.5 min while breathing room air (normoxia) and after being titrated to an arterial oxygen saturation ≈80% (hypoxemia). We measured brachial artery blood flow by high-resolution duplex ultrasound, while continuously monitoring vascular conductance and mean arterial pressure using finger photoplethysmography. Blood was sampled during the final 30 s of each stage from an indwelling cannula. Blood viscosity was measured to facilitate calculation of accurate shear stresses. Erythrocytes were assessed for levels of phosphorylated RBC-NOS1177 and cellular deformability from blood collected at rest and during exercise. Forearm exercise increased blood flow, vascular conductance, and vascular shear stress, which coincided with a 2.7 ± 0.6-fold increase in RBC-NOS1177 phosphorylation (P < 0.0001) and increased cellular deformability (P < 0.0001) under normoxia. When compared with normoxia, hypoxemia elevated vascular conductance and shear stress (P < 0.05) at rest, while cellular deformability (P < 0.01) and RBC-NOS1177 phosphorylation (P < 0.01) increased. Hypoxemic exercise elicited further increases in vascular conductance, shear stress, and cell deformability (P < 0.0001), although a subject-specific response in RBC-NOS1177 phosphorylation was observed. Our data yield novel insights into the manner that hemodynamic force and oxygen tension modulate RBC-NOS in vivo.
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Affiliation(s)
- Jeffrey A Leo
- Exercise and Sport, School of Health Sciences and Social Work, Griffith University, Gold Coast, Queensland, Australia
| | - Surendran Sabapathy
- Exercise and Sport, School of Health Sciences and Social Work, Griffith University, Gold Coast, Queensland, Australia
| | - Lennart Kuck
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Michael J Simmonds
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
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4
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Della Guardia L, Wang L. Fine particulate matter induces adipose tissue expansion and weight gain: Pathophysiology. Obes Rev 2023; 24:e13552. [PMID: 36700515 DOI: 10.1111/obr.13552] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 11/25/2022] [Accepted: 01/08/2023] [Indexed: 01/27/2023]
Abstract
Dysregulations in energy balance represent a major driver of obesity. Recent evidence suggests that environmental factors also play a pivotal role in inducing weight gain. Chronic exposure to fine particulate matter (PM2.5 ) is associated with white adipose tissue (WAT) expansion in animals and higher rates of obesity in humans. This review discusses metabolic adaptions in central and peripheral tissues that promote energy storage and WAT accumulation in PM2.5 -exposed animals and humans. Chronic PM2.5 exposure produces inflammation and leptin resistance in the hypothalamus, decreasing energy expenditure and increasing food intake. PM2.5 promotes the conversion of brown adipocytes toward the white phenotype, resulting in decreased energy expenditure. The development of inflammation in WAT can stimulate adipogenesis and hampers catecholamine-induced lipolysis. PM2.5 exposure affects the thyroid, reducing the release of thyroxine and tetraiodothyronine. In addition, PM2.5 exposure compromises skeletal muscle fitness by inhibiting Nitric oxide (NO)-dependent microvessel dilation and impairing mitochondrial oxidative capacity, with negative effects on energy expenditure. This evidence suggests that pathological alterations in the hypothalamus, brown adipose tissue, WAT, thyroid, and skeletal muscle can alter energy homeostasis, increasing lipid storage and weight gain in PM2.5 -exposed animals and humans. Further studies will enrich this pathophysiological model.
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Affiliation(s)
- Lucio Della Guardia
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Ling Wang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, China
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5
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Mullen M, Williams K, LaRocca T, Duke V, Hambright WS, Ravuri SK, Bahney CS, Ehrhart N, Huard J. Mechanical strain drives exosome production, function, and miRNA cargo in C2C12 muscle progenitor cells. J Orthop Res 2022; 41:1186-1197. [PMID: 36250617 DOI: 10.1002/jor.25467] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 06/19/2022] [Accepted: 10/08/2022] [Indexed: 02/04/2023]
Abstract
Mesenchymal stem cells (MSCs) have been proven to promote tissue repair. However, concerns related to their clinical application and regulatory hurdles remain. Recent data has demonstrated the proregenerative secretome of MSCs can result in similar effects in the absence of the cells themselves. Within the secretome, exosomes have emerged as a promising regenerative component. Exosomes, which are nanosized lipid vesicles secreted by cells, encapsulate micro-RNA (miRNA), RNA, and proteins that drive MSCs regenerative potential with cell specific content. As such, there is an opportunity to optimize the regenerative potential of MSCs, and thus their secreted exosome fraction, to improve clinical efficacy. Exercise is one factor that has been shown to improve muscle progenitor cell function and regenerative potential. However, the effect of exercise on MSC exosome content and function is still unclear. To address this, we used an in vitro culture system to evaluate the effects of mechanical strain, an exercise mimetic, on C2C12 (muscle progenitor cell) exosome production and proregenerative function. Our results indicate that the total exosome production is increased by mechanical strain and can be regulated with different tensile loading regimens. Furthermore, we found that exosomes from mechanically stimulated cells increase proliferation and myogenic differentiation of naïve C2C12 cells. Lastly, we show that exosomal miRNA cargo is differentially expressed following strain. Gene ontology mapping suggests positive regulation of bone morphogenetic protein signaling, regulation of actin-filament-based processes, and muscle cell apoptosis may be at least partially responsible for the proregenerative effects of exosomes from mechanically stimulated C2C12 muscle progenitor cells.
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Affiliation(s)
- Michael Mullen
- Linda and Mitch Hart Center for Regenerative and Personalized Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado, USA
| | - Katherine Williams
- Department of Clinical Sciences, Flint Animal Cancer Center, Colorado State University, Fort Collins, Colorado, USA
| | - Tom LaRocca
- Deptartment of Health and Exercise Science, Center for Healthy Aging, Colorado State University, Fort Collins, Colorado, USA
| | - Victoria Duke
- Linda and Mitch Hart Center for Regenerative and Personalized Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado, USA
| | - William S Hambright
- Linda and Mitch Hart Center for Regenerative and Personalized Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado, USA
| | - Sudheer K Ravuri
- Linda and Mitch Hart Center for Regenerative and Personalized Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado, USA
| | - Chelsea S Bahney
- Linda and Mitch Hart Center for Regenerative and Personalized Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado, USA.,Department of Clinical Sciences, Flint Animal Cancer Center, Colorado State University, Fort Collins, Colorado, USA.,Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital (ZSFG), University of California, San Francisco (UCSF), San Francisco, California, USA
| | - Nicole Ehrhart
- Department of Clinical Sciences, Flint Animal Cancer Center, Colorado State University, Fort Collins, Colorado, USA.,Columbine Health Systems Center for Healthy Aging, Colorado State University, Fort Collins, Colorado, USA
| | - Johnny Huard
- Linda and Mitch Hart Center for Regenerative and Personalized Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado, USA.,Department of Clinical Sciences, Flint Animal Cancer Center, Colorado State University, Fort Collins, Colorado, USA
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6
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Moritz CEJ, Vieira AF, de Melo-Marins D, Figueiró F, Battastini AMO, Reischak-Oliveira A. Effects of physical exercise on the functionality of human nucleotidases: A systematic review. Physiol Rep 2022; 10:e15464. [PMID: 36117383 PMCID: PMC9483616 DOI: 10.14814/phy2.15464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/21/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023] Open
Abstract
Nucleotidases contribute to the regulation of inflammation, coagulation, and cardiovascular activity. Exercise promotes biological adaptations, but its effects on nucleotidase activities and expression are unclear. The objective of this study was to review systematically the effects of exercise on nucleotidase functionality in healthy and unhealthy subjects. The MEDLINE, EMBASE, Cochrane Library, and Web of Science databases were searched to identify, randomized clinical trials, non-randomized clinical trials, uncontrolled clinical trials, quasi-experimental, pre-, and post-interventional studies that evaluated the effects of exercise on nucleotidases in humans, and was not limited by language and date. Two independent reviewers performed the study selection, data extraction, and assessment of risk of bias. Of the 203 articles identified, 12 were included in this review. Eight studies reported that acute exercise, in healthy and unhealthy subjects, elevated the activities or expression of nucleotidases. Four studies evaluated the effects of chronic training on nucleotidase activities in the platelets and lymphocytes of patients with metabolic syndrome, chronic kidney disease, and hypertension and found a decrease in nucleotidase activities in these conditions. Acute and chronic exercise was able to modify the blood plasma and serum levels of nucleotides and nucleosides. Our results suggest that short- and long-term exercise modulate nucleotidase functionality. As such, purinergic signaling may represent a novel molecular adaptation in inflammatory, thrombotic, and vascular responses to exercise.
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Affiliation(s)
- Cesar Eduardo Jacintho Moritz
- Programa de Pós-Graduação em Ciências do Movimento Humano, Escola de Educação Física, Fisioterapia e Dança (ESEFID), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Alexandra Ferreira Vieira
- Programa de Pós-Graduação em Ciências do Movimento Humano, Escola de Educação Física, Fisioterapia e Dança (ESEFID), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Denise de Melo-Marins
- Programa de Pós-Graduação em Ciências do Movimento Humano, Escola de Educação Física, Fisioterapia e Dança (ESEFID), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Fabrício Figueiró
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Departamento do Bioquímica, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Ana Maria Oliveira Battastini
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Departamento do Bioquímica, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Alvaro Reischak-Oliveira
- Programa de Pós-Graduação em Ciências do Movimento Humano, Escola de Educação Física, Fisioterapia e Dança (ESEFID), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
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7
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He Y, van Mever M, Yang W, Huang L, Ramautar R, Rijksen Y, Vermeij WP, Hoeijmakers JHJ, Harms AC, Lindenburg PW, Hankemeier T. A Sample Preparation Method for the Simultaneous Profiling of Signaling Lipids and Polar Metabolites in Small Quantities of Muscle Tissues from a Mouse Model for Sarcopenia. Metabolites 2022; 12:metabo12080742. [PMID: 36005613 PMCID: PMC9413361 DOI: 10.3390/metabo12080742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/16/2022] Open
Abstract
The metabolic profiling of a wide range of chemical classes relevant to understanding sarcopenia under conditions in which sample availability is limited, e.g., from mouse models, small muscles, or muscle biopsies, is desired. Several existing metabolomics platforms that include diverse classes of signaling lipids, energy metabolites, and amino acids and amines would be informative for suspected biochemical pathways involved in sarcopenia. The sample limitation requires an optimized sample preparation method with minimal losses during isolation and handling and maximal accuracy and reproducibility. Here, two developed sample preparation methods, BuOH-MTBE-Water (BMW) and BuOH-MTBE-More-Water (BMMW), were evaluated and compared with previously reported methods, Bligh-Dyer (BD) and BuOH-MTBE-Citrate (BMC), for their suitability for these classes. The most optimal extraction was found to be the BMMW method, with the highest extraction recovery of 63% for the signaling lipids and 81% for polar metabolites, and an acceptable matrix effect (close to 1.0) for all metabolites of interest. The BMMW method was applied on muscle tissues as small as 5 mg (dry weight) from the well-characterized, prematurely aging, DNA repair-deficient Ercc1∆/- mouse mutant exhibiting multiple-morbidities, including sarcopenia. We successfully detected 109 lipids and 62 polar targeted metabolites. We further investigated whether fast muscle tissue isolation is necessary for mouse sarcopenia studies. A muscle isolation procedure involving 15 min at room temperature revealed a subset of metabolites to be unstable; hence, fast sample isolation is critical, especially for more oxidative muscles. Therefore, BMMW and fast muscle tissue isolation are recommended for future sarcopenia studies. This research provides a sensitive sample preparation method for the simultaneous extraction of non-polar and polar metabolites from limited amounts of muscle tissue, supplies a stable mouse muscle tissue collection method, and methodologically supports future metabolomic mechanistic studies of sarcopenia.
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Affiliation(s)
- Yupeng He
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Marlien van Mever
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Wei Yang
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Luojiao Huang
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Rawi Ramautar
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Yvonne Rijksen
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Wilbert P. Vermeij
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Jan H. J. Hoeijmakers
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands
- Institute for Genome Stability in Aging and Disease, Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Amy C. Harms
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Peter W. Lindenburg
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Research Group Metabolomics, Leiden Center for Applied Bioscience, University of Applied Sciences Leiden, 2333 CK Leiden, The Netherlands
| | - Thomas Hankemeier
- Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Correspondence: ; Tel.: +31-71-527-1340
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8
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Darvish S, Coppock ME, Murray KO. Age-related impairments in ATP release by red blood cells as an important contributor to declines in skeletal muscle blood flow in older adults. J Physiol 2022; 600:3643-3645. [PMID: 35818302 PMCID: PMC9378623 DOI: 10.1113/jp283367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 07/08/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Sanna Darvish
- Department of Integrative Physiology, University of Colorado Boulder
| | | | - Kevin O Murray
- Department of Integrative Physiology, University of Colorado Boulder
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9
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González-Alonso J. Targeting red cell-derived ATP signalling to improve the aged muscle circulation. J Physiol 2022; 600:3215-3216. [PMID: 35716371 DOI: 10.1113/jp283322] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- José González-Alonso
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, Middlesex, UB8 3PH, UK
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10
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Nyberg M, Jones AM. Matching of O2 Utilization and O2 Delivery in Contracting Skeletal Muscle in Health, Aging, and Heart Failure. Front Physiol 2022; 13:898395. [PMID: 35774284 PMCID: PMC9237395 DOI: 10.3389/fphys.2022.898395] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/05/2022] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle is one of the most dynamic metabolic organs as evidenced by increases in metabolic rate of >150-fold from rest to maximal contractile activity. Because of limited intracellular stores of ATP, activation of metabolic pathways is required to maintain the necessary rates of ATP re-synthesis during sustained contractions. During the very early phase, phosphocreatine hydrolysis and anaerobic glycolysis prevails but as activity extends beyond ∼1 min, oxidative phosphorylation becomes the major ATP-generating pathway. Oxidative metabolism of macronutrients is highly dependent on the cardiovascular system to deliver O2 to the contracting muscle fibres, which is ensured through a tight coupling between skeletal muscle O2 utilization and O2 delivery. However, to what extent O2 delivery is ideal in terms of enabling optimal metabolic and contractile function is context-dependent and determined by a complex interaction of several regulatory systems. The first part of the review focuses on local and systemic mechanisms involved in the regulation of O2 delivery and how integration of these influences the matching of skeletal muscle O2 demand and O2 delivery. In the second part, alterations in cardiovascular function and structure associated with aging and heart failure, and how these impact metabolic and contractile function, will be addressed. Where applicable, the potential of exercise training to offset/reverse age- and disease-related cardiovascular declines will be highlighted in the context of skeletal muscle metabolic function. The review focuses on human data but also covers animal observations.
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Affiliation(s)
- Michael Nyberg
- Vascular Biology, Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark
- *Correspondence: Michael Nyberg,
| | - Andrew M. Jones
- Department of Sport and Health Sciences, University of Exeter, Exeter, United Kingdom
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Shannon OM, Clifford T, Seals DR, Craighead DH, Rossman MJ. Nitric oxide, aging and aerobic exercise: Sedentary individuals to Master's athletes. Nitric Oxide 2022; 125-126:31-39. [PMID: 35705144 DOI: 10.1016/j.niox.2022.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 05/27/2022] [Accepted: 06/06/2022] [Indexed: 12/12/2022]
Abstract
Aging is associated with a decline in physiological function and exercise performance. These effects are mediated, at least in part, by an age-related decrease in the bioavailability of nitric oxide (NO), a ubiquitous gasotransmitter and regulator of myriad physiological processes. The decrease in NO bioavailability with aging is especially apparent in sedentary individuals, whereas older, physically active individuals maintain higher levels of NO with advancing age. Strategies which enhance NO bioavailability (including nutritional supplementation) have been proposed as a potential means of reducing the age-related decrease in physiological function and enhancing exercise performance and may be of interest to a range of older individuals including those taking part in competitive sport. In this brief review we discuss the effects of aging on physiological function and endurance exercise performance, and the potential role of changes in NO bioavailability in these processes. We also provide a summary of current evidence for dietary supplementation with substrates for NO production - including inorganic nitrate and nitrite, l-arginine and l-citrulline - for improving exercise capacity/performance in older adults. Additionally, we discuss the (limited) evidence on the effects of (poly)phenols and other dietary antioxidants on NO bioavailability in older individuals. Finally, we provide suggestions for future research.
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Affiliation(s)
- Oliver M Shannon
- Human Nutrition Research Centre, Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK.
| | - Tom Clifford
- School of Sport, Exercise and Health Science, Loughborough University, Loughborough, UK
| | - Douglas R Seals
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Daniel H Craighead
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Matthew J Rossman
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
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Racine ML, Terwoord JD, Ketelhut NB, Bachman NP, Richards JC, Luckasen GJ, Dinenno FA. Rho-kinase inhibition improves haemodynamic responses and circulating ATP during hypoxia and moderate intensity handgrip exercise in healthy older adults. J Physiol 2022; 600:3265-3285. [PMID: 35575293 PMCID: PMC9288513 DOI: 10.1113/jp282730] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 05/09/2022] [Indexed: 11/21/2022] Open
Abstract
Abstract Skeletal muscle haemodynamics and circulating adenosine triphosphate (ATP) responses during hypoxia and exercise are blunted in older (OA) vs. young (YA) adults, which may be associated with impaired red blood cell (RBC) ATP release. Rho‐kinase inhibition improves deoxygenation‐induced ATP release from OA isolated RBCs. We tested the hypothesis that Rho‐kinase inhibition (via fasudil) in vivo would improve local haemodynamic and ATP responses during hypoxia and exercise in OA. Healthy YA (25 ± 3 years; n = 12) and OA (65 ± 5 years; n = 13) participated in a randomized, double‐blind, placebo‐controlled, crossover study on two days (≥5 days between visits). A forearm deep venous catheter was used to administer saline/fasudil and sample venous plasma ATP ([ATP]V). Forearm vascular conductance (FVC) and [ATP]V were measured at rest, during isocapnic hypoxia (80% SpO2), and during graded rhythmic handgrip exercise that was similar between groups (5, 15 and 25% maximum voluntary contraction (MVC)). Isolated RBC ATP release was measured during normoxia/hypoxia. With saline, ΔFVC was lower (P < 0.05) in OA vs. YA during hypoxia (∼60%) and during 15 and 25% MVC (∼25–30%), and these impairments were abolished with fasudil. Similarly, [ATP]V and ATP effluent responses from normoxia to hypoxia and rest to 25% MVC were lower in OA vs. YA and improved with fasudil (P < 0.05). Isolated RBC ATP release during hypoxia was impaired in OA vs. YA (∼75%; P < 0.05), which tended to improve with fasudil in OA (P = 0.082). These data suggest Rho‐kinase inhibition improves haemodynamic responses to hypoxia and moderate intensity exercise in OA, which may be due in part to improved circulating ATP.
![]() Key points Skeletal muscle blood flow responses to hypoxia and exercise are impaired with age. Blunted increases in circulating ATP, a vasodilator, in older adults may contribute to age‐related impairments in haemodynamics. Red blood cells (RBCs) are a primary source of circulating ATP, and treating isolated RBCs with a Rho‐kinase inhibitor improves age‐related impairments in deoxygenation‐induced RBC ATP release. In this study, treating healthy older adults systemically with the Rho‐kinase inhibitor fasudil improved blood flow and circulating ATP responses during hypoxia and moderate intensity handgrip exercise compared to young adults, and also tended to improve isolated RBC ATP release. Improved blood flow regulation with fasudil was also associated with increased skeletal muscle oxygen delivery during hypoxia and exercise in older adults. This is the first study to demonstrate that Rho‐kinase inhibition can significantly improve age‐related impairments in haemodynamic and circulating ATP responses to physiological stimuli, which may have therapeutic implications.
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Affiliation(s)
- Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Nathaniel B Ketelhut
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Nate P Bachman
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies, University of Colorado Health, Loveland, CO, 80538, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
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Optimized HPLC method to elucidate the complex purinergic signaling dynamics that regulate ATP, ADP, AMP, and adenosine levels in human blood. Purinergic Signal 2022; 18:223-239. [DOI: 10.1007/s11302-022-09842-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/06/2022] [Indexed: 10/19/2022] Open
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14
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McMahon TJ, Darrow CC, Hoehn BA, Zhu H. Generation and Export of Red Blood Cell ATP in Health and Disease. Front Physiol 2021; 12:754638. [PMID: 34803737 PMCID: PMC8602689 DOI: 10.3389/fphys.2021.754638] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/05/2021] [Indexed: 12/16/2022] Open
Abstract
Metabolic homeostasis in animals depends critically on evolved mechanisms by which red blood cell (RBC) hemoglobin (Hb) senses oxygen (O2) need and responds accordingly. The entwined regulation of ATP production and antioxidant systems within the RBC also exploits Hb-based O2-sensitivity to respond to various physiologic and pathophysiologic stresses. O2 offloading, for example, promotes glycolysis in order to generate both 2,3-DPG (a negative allosteric effector of Hb O2 binding) and ATP. Alternatively, generation of the nicotinamide adenine dinucleotide phosphate (NADPH) critical for reducing systems is favored under the oxidizing conditions of O2 abundance. Dynamic control of ATP not only ensures the functional activity of ion pumps and cellular flexibility, but also contributes to the availability of vasoregulatory ATP that can be exported when necessary, for example in hypoxia or upon RBC deformation in microvessels. RBC ATP export in response to hypoxia or deformation dilates blood vessels in order to promote efficient O2 delivery. The ability of RBCs to adapt to the metabolic environment via differential control of these metabolites is impaired in the face of enzymopathies [pyruvate kinase deficiency; glucose-6-phosphate dehydrogenase (G6PD) deficiency], blood banking, diabetes mellitus, COVID-19 or sepsis, and sickle cell disease. The emerging availability of therapies capable of augmenting RBC ATP, including newly established uses of allosteric effectors and metabolite-specific additive solutions for RBC transfusates, raises the prospect of clinical interventions to optimize or correct RBC function via these metabolite delivery mechanisms.
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Affiliation(s)
- Timothy J McMahon
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
| | - Cole C Darrow
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
| | - Brooke A Hoehn
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
| | - Hongmei Zhu
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Durham VA and Duke University Medical Centers, Durham, NC, United States
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15
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DeLorey DS. Sympathetic vasoconstriction in skeletal muscle: Modulatory effects of aging, exercise training, and sex. Appl Physiol Nutr Metab 2021; 46:1437-1447. [PMID: 34348066 DOI: 10.1139/apnm-2021-0399] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sympathetic nervous system (SNS) is a critically important regulator of the cardiovascular system. The SNS controls cardiac output and its distribution, as well as peripheral vascular resistance and blood pressure at rest and during exercise. Aging is associated with increased blood pressure and decreased skeletal muscle blood flow at rest and in response to exercise. The mechanisms responsible for the blunted skeletal muscle blood flow response to dynamic exercise with aging have not been fully elucidated; however, increased muscle sympathetic nerve activity (MSNA), elevated vascular resistance and a decline in endothelium-dependent vasodilation are commonly reported in older adults. In contrast to aging, exercise training has been shown to reduce blood pressure and enhance skeletal muscle vascular function. Exercise training has been shown to enhance nitric oxide-dependent vascular function and may improve the vasodilatory capacity of the skeletal muscle vasculature; however, surprisingly little is known about the effect of exercise training on the neural control of circulation. The control of blood pressure and skeletal muscle blood flow also differs between males and females. Blood pressure and MSNA appear to be lower in young females compared to males. However, females experience a larger increase in MSNA with aging compared to males. The mechanism(s) for the altered SNS control of vascular function in females remain to be determined. Novelty: • This review will summarize our current understanding of the effects of aging, exercise training and sex on sympathetic vasoconstriction at rest and during exercise. • Areas where additional research is needed are also identified.
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Affiliation(s)
- Darren S DeLorey
- University of Alberta, Faculty of Kinesiology, Sport, and Recreation, Edmonton, Alberta, Canada;
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Terwoord JD, Racine ML, Hearon CM, Luckasen GJ, Dinenno FA. ATP and acetylcholine interact to modulate vascular tone and α 1-adrenergic vasoconstriction in humans. J Appl Physiol (1985) 2021; 131:566-574. [PMID: 34166116 DOI: 10.1152/japplphysiol.00205.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vascular endothelium senses and integrates numerous inputs to regulate vascular tone. Recent evidence reveals complex signal processing within the endothelium, yet little is known about how endothelium-dependent stimuli interact to regulate blood flow. We tested the hypothesis that combined stimulation of the endothelium with adenosine triphosphate (ATP) and acetylcholine (ACh) elicits greater vasodilation and attenuates α1-adrenergic vasoconstriction compared with combination of ATP or ACh with the endothelium-independent dilator sodium nitroprusside (SNP). We assessed forearm vascular conductance (FVC) in young adults (6 women, 7 men) during local intra-arterial infusion of ATP, ACh, or SNP alone and in the following combinations: ATP + ACh, SNP + ACh, and ATP + SNP, wherein the second dilator was coinfused after attaining steady state with the first dilator. By design, each dilator evoked a similar response when infused separately (ΔFVC, ATP: 48 ± 4; ACh: 57 ± 6; SNP: 53 ± 6 mL·min-1·100 mmHg-1; P ≥ 0.62). Combined infusion of the endothelium-dependent dilators evoked greater vasodilation than combination of either dilator with SNP (ΔFVC from first dilator, ATP + ACh: 45 ± 9 vs. SNP + ACh: 18 ± 7 and ATP + SNP: 26 ± 4 mL·min-1·100 mmHg-1, P < 0.05). Phenylephrine was subsequently infused to evaluate α1-adrenergic vasoconstriction. Phenylephrine elicited less vasoconstriction during infusion of ATP or ACh versus SNP (ΔFVC, -25 ± 3 and -29 ± 4 vs. -48 ± 3%; P < 0.05). The vasoconstrictor response to phenylephrine was further diminished during combined infusion of ATP + ACh (-13 ± 3%; P < 0.05 vs. ATP or ACh alone) and was less than that observed when either dilator was combined with SNP (SNP + ACh: -26 ± 3%; ATP + SNP: -31 ± 4%; both P < 0.05 vs. ATP + ACh). We conclude that endothelium-dependent agonists interact to elicit vasodilation and limit α1-adrenergic vasoconstriction in humans.NEW & NOTEWORTHY The results of this study highlight the vascular endothelium as a critical site for integration of vasomotor signals in humans. To our knowledge, this is the first study to demonstrate that combined stimulation of the endothelium with ATP and ACh results in enhanced vasodilation compared with combination of either ATP or ACh with an endothelium-independent dilator. Furthermore, we show that ATP and ACh interact to modulate α1-adrenergic vasoconstriction in human skeletal muscle in vivo.
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Affiliation(s)
- Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, Colorado
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
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Kirby BS, Sparks MA, Lazarowski ER, Lopez Domowicz DA, Zhu H, McMahon TJ. Pannexin 1 channels control the hemodynamic response to hypoxia by regulating O 2-sensitive extracellular ATP in blood. Am J Physiol Heart Circ Physiol 2021; 320:H1055-H1065. [PMID: 33449849 PMCID: PMC7988759 DOI: 10.1152/ajpheart.00651.2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 12/23/2022]
Abstract
Pannexin 1 (Panx1) channels export ATP and may contribute to increased concentration of the vasodilator ATP in plasma during hypoxia in vivo. We hypothesized that Panx1 channels and associated ATP export contribute to hypoxic vasodilation, a mechanism that facilitates the matching of oxygen delivery to metabolic demand of tissue. Male and female mice devoid of Panx1 (Panx1-/-) and wild-type controls (WT) were anesthetized, mechanically ventilated, and instrumented with a carotid artery catheter or femoral artery flow transducer for hemodynamic and plasma ATP monitoring during inhalation of 21% (normoxia) or 10% oxygen (hypoxia). ATP export from WT vs. Panx1-/-erythrocytes (RBC) was determined ex vivo via tonometer experimentation across progressive deoxygenation. Mean arterial pressure (MAP) was similar in Panx1-/- (n = 6) and WT (n = 6) mice in normoxia, but the decrease in MAP in hypoxia seen in WT was attenuated in Panx1-/- mice (-16 ± 9% vs. -2 ± 8%; P < 0.05). Hindlimb blood flow (HBF) was significantly lower in Panx1-/- (n = 6) vs. WT (n = 6) basally, and increased in WT but not Panx1-/- mice during hypoxia (8 ± 6% vs. -10 ± 13%; P < 0.05). Estimation of hindlimb vascular conductance using data from the MAP and HBF experiments showed an average response of 28% for WT vs. -9% for Panx1-/- mice. Mean venous plasma ATP during hypoxia was 57% lower in Panx1-/- (n = 6) vs. WT mice (n = 6; P < 0.05). Mean hypoxia-induced ATP export from RBCs from Panx1-/- mice (n = 8) was 82% lower than that from WT (n = 8; P < 0.05). Panx1 channels participate in hemodynamic responses consistent with hypoxic vasodilation by regulating hypoxia-sensitive extracellular ATP levels in blood.NEW & NOTEWORTHY Export of vasodilator ATP from red blood cells requires pannexin 1. Blood plasma ATP elevations in response to hypoxia in mice require pannexin 1. Hemodynamic responses to hypoxia are accompanied by increased plasma ATP in mice in vivo and require pannexin 1.
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Affiliation(s)
- Brett S Kirby
- Division of Hematology, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University Medical Center, Durham, North Carolina
- Departments of Medicine and Research and Development, Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Eduardo R Lazarowski
- Department of Medicine, Marsico Lung Institute/UNC Cystic Fibrosis Research Center, University of North Carolina, Chapel Hill, North Carolina
| | - Denise A Lopez Domowicz
- Division of Critical Care Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina
| | - Hongmei Zhu
- Division of Pulmonary, Allergy, Critical Care Medicine, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Timothy J McMahon
- Department of Medicine, Marsico Lung Institute/UNC Cystic Fibrosis Research Center, University of North Carolina, Chapel Hill, North Carolina
- Division of Pulmonary, Allergy, Critical Care Medicine, Department of Medicine, Duke University Medical Center, Durham, North Carolina
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18
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Jaffri AH, Lynch M, Saliba SA, Hart JM. Quadriceps Oxygenation During Exercise in Patients With Anterior Cruciate Ligament Reconstruction. J Athl Train 2021; 56:170-176. [PMID: 33400786 DOI: 10.4085/1062-6050-0415.19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT The causes of persistent muscle weakness after anterior cruciate ligament reconstruction (ACLR) are not well known. Changes in muscle oxygenation have been proposed as a possible mechanism. OBJECTIVE To investigate changes in quadriceps muscle oxygenation during knee extension in ACLR-involved and ACLR-uninvolved limbs. DESIGN Case-control study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 20 individuals: 10 patients with primary, unilateral ACLR (7 women, 3 men; age = 22.90 ± 3.45 years, height = 170.81 ± 7.93 cm, mass = 73.7 ± 15.1 kg) and 10 matched control individuals (7 women, 3 men; age = 21.50 ± 2.99 years, height = 170.4 ± 10.7 cm, mass = 68.86 ± 9.51 kg). INTERVENTION(S) Each participant completed a single data-collection session consisting of 5-second isometric contractions at 25%, 50%, and 75% of the volitional maximum followed by a 30-second maximal isometric knee-extension contraction. MAIN OUTCOME MEASURE(S) Oxygenated hemoglobin (O2Hb) measures in the reconstructed thigh were continuously recorded (versus the uninvolved contralateral limb as well as the nondominant thigh of healthy control individuals) using 3 wearable, wireless near-infrared spectroscopy units placed superficially to the vastus medialis, vastus lateralis, and rectus femoris muscles. Relative changes in oxygenation were ensemble averaged and plotted for each contraction intensity with associated 90% confidence intervals (CIs). Statistical significance occurred where portions of the exercise trials with confidence intervals on the O2Hb graph did not overlap. Effect sizes (Cohen d, 90% CI) were determined for statistical significance. RESULTS We observed less relative change in O2Hb in patients with ACLR than in healthy control participants in the rectus femoris at 25% (d = 2.1; 90% CI = 1.5, 2.7), 50% (d = 2.8; 90% CI = 2.6, 2.9), and 75% (d = 2.0; 90% CI = 1.9, 2.2) and for the vastus medialis at 75% (d = 1.5; 90% CI = 1.4, 1.5) and 100% (d = 2.6; 90% CI = 2.5, 2.7). Less relative change in O2Hb was also noted for the vastus medialis in ACLR-involved versus ACLR-uninvolved limbs at 100% (d = 2.62; 90% CI = 2.54, 2.70). CONCLUSIONS Quadriceps muscle oxygenation during exercise differed between patients with ACLR versus healthy control individuals. However, not all portions of the quadriceps were affected uniformly across contraction intensities.
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Adam RJ. Rescue of impaired sympatholysis in older adults by exogenous administration of endothelium-dependent vasodilatory signal. J Physiol 2020; 598:3549-3551. [PMID: 32530043 DOI: 10.1113/jp280108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/03/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Ryan J Adam
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA
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A Translational In Vivo and In Vitro Metabolomic Study Reveals Altered Metabolic Pathways in Red Blood Cells of Type 2 Diabetes. J Clin Med 2020; 9:jcm9061619. [PMID: 32471219 PMCID: PMC7355709 DOI: 10.3390/jcm9061619] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/19/2020] [Accepted: 05/24/2020] [Indexed: 12/21/2022] Open
Abstract
Clinical parameters used in type 2 diabetes mellitus (T2D) diagnosis and monitoring such as glycosylated haemoglobin (HbA1c) are often unable to capture important information related to diabetic control and chronic complications. In order to search for additional biomarkers, we performed a pilot study comparing T2D patients with healthy controls matched by age, gender, and weight. By using 1H-nuclear magnetic resonance (NMR) based metabolomics profiling of red blood cells (RBCs), we found that the metabolic signature of RBCs in T2D subjects differed significantly from non-diabetic controls. Affected metabolites included glutathione, 2,3-bisphophoglycerate, inosinic acid, lactate, 6-phosphogluconate, creatine and adenosine triphosphate (ATP) and several amino acids such as leucine, glycine, alanine, lysine, aspartate, phenylalanine and tyrosine. These results were validated by an independent cohort of T2D and control patients. An analysis of the pathways in which these metabolites were involved showed that energetic and redox metabolism in RBCs were altered in T2D, as well as metabolites transported by RBCs. Taken together, our results revealed that the metabolic profile of RBCs can discriminate healthy controls from T2D patients. Further research is needed to determine whether metabolic fingerprint in RBC could be useful to complement the information obtained from HbA1c and glycemic variability as well as its potential role in the diabetes management.
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Terwoord JD, Hearon CM, Racine ML, Ketelhut NB, Luckasen GJ, Richards JC, Dinenno FA. K IR channel activation links local vasodilatation with muscle fibre recruitment during exercise in humans. J Physiol 2020; 598:2621-2636. [PMID: 32329892 DOI: 10.1113/jp279682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 04/17/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS During exercise, blood flow to working skeletal muscle increases in parallel with contractile activity such that oxygen delivery is sufficient to meet metabolic demand. K+ released from active skeletal muscle fibres could facilitate vasodilatation in proportion to the degree of muscle fibre recruitment. Once released, K+ stimulates inwardly rectifying K+ (KIR ) channels on the vasculature to elicit an increase in blood flow. In the present study, we demonstrate that KIR channels mediate the rapid vasodilatory response to an increase in exercise intensity. We also show that KIR channels augment vasodilatation during exercise which demands greater muscle fibre recruitment independent of the total amount of work performed. These results suggest that K+ plays a key role in coupling the magnitude of vasodilatation to the degree of contractile activity. Ultimately, the findings from this study help us understand the signalling mechanisms that regulate muscle blood flow in humans. ABSTRACT Blood flow to active skeletal muscle is augmented with greater muscle fibre recruitment. We tested whether activation of inwardly rectifying potassium (KIR ) channels underlies vasodilatation with elevated muscle fibre recruitment when work rate is increased (Protocol 1) or held constant (Protocol 2). We assessed forearm vascular conductance (FVC) during rhythmic handgrip exercise under control conditions and during local inhibition of KIR channels (intra-arterial BaCl2 ). In Protocol 1, healthy volunteers performed mild handgrip exercise for 3 min, then transitioned to moderate intensity for 30 s. BaCl2 eliminated vasodilatation during the first contraction at the moderate workload (ΔFVC, BaCl2 : -1 ± 17 vs. control: 30 ± 28 ml min-1 100 mmHg-1 ; n = 9; P = 0.004) and attenuated the 30 s area under the curve by 56 ± 14% (n = 9; P < 0.0001). In Protocol 2, participants performed two exercise bouts in which muscle fibre recruitment was manipulated while total contractile work was held constant via reciprocal changes in contraction frequency: (1) low fibre recruitment, with contractions at 12.5% maximal voluntary contraction once every 4 s and (2) high fibre recruitment, with contractions at 25% maximal voluntary contraction once every 8 s. Under control conditions, steady-state FVC was augmented in high vs. low fibre recruitment (211 ± 90 vs. 166 ± 73 ml min-1 ⋅100 mmHg-1 ; n = 10; P = 0.0006), whereas BaCl2 abolished the difference between high and low fibre recruitment (134 ± 59 vs. 134 ± 63 ml min-1 100 mmHg-1 ; n = 10; P = 0.85). These findings demonstrate that KIR channel activation is a key mechanism linking local vasodilatation with muscle fibre recruitment during exercise.
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Affiliation(s)
- Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Nathaniel B Ketelhut
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
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22
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Hearon CM, Richards JC, Racine ML, Luckasen GJ, Larson DG, Dinenno FA. Augmentation of endothelium-dependent vasodilatory signalling improves functional sympatholysis in contracting muscle of older adults. J Physiol 2020; 598:2323-2336. [PMID: 32306393 DOI: 10.1113/jp279462] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/14/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction (functional sympatholysis) is critical for maintaining blood flow during exercise-mediated sympathoexcitation. Functional sympatholysis and endothelial function are impaired with ageing, resulting in compromised blood flow and oxygen delivery to contracting skeletal muscle during exercise. In the present study, intra-arterial infusion of ACh or ATP to augment endothelium-dependent signalling during exercise attenuated α1 -adrenergic vasoconstriction in the contracting muscle of older adults. The vascular signalling mechanisms capable of functional sympatholysis are preserved in healthy ageing, and thus the age-related impairment in functional sympatholysis probably results from the loss of a functional signal (e.g. plasma [ATP]) as opposed to an intrinsic endothelial dysfunction. ABSTRACT The ability of contracting skeletal muscle to attenuate sympathetic α-adrenergic vasoconstriction ('functional sympatholysis') is impaired with age. In young adults, increasing endothelium-dependent vasodilatory signalling during mild exercise augments sympatholysis. In the present study, we tested the hypothesis that increasing endothelium-dependent signalling during exercise in older adults can improve sympatholysis. In 16 older individuals (Protocol 1, n = 8; Protocol 2, n = 8), we measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to local intra-arterial infusion of phenylephrine (PE; α1 -agonist) during (i) infusion of an endothelium-dependent vasodilator alone (Protocol 1: ACh or Protocol 2: low dose ATP); (ii) mild handgrip exercise (5% maximum voluntary contraction; MVC); (iii) moderate handgrip exercise (15% MVC); and (iv) mild or moderate handgrip exercise + infusion of ACh or ATP to augment endothelium-dependent signalling. PE caused robust vasoconstriction in resting skeletal muscle during control vasodilator infusions (ΔFVC: ACh: -31 ± 3 and ATP: -30 ± 4%). PE-mediated vasoconstriction was not attenuated by mild or moderate intensity exercise (ΔFVC: 5% MVC: -30 ± 9; 15% MVC: -33 ± 8%; P > 0.05 vs. control ACh and ATP), indicative of impaired sympatholysis, and ACh or ATP infusion during mild exercise did not impact this response. However, augmentation of endothelium-dependent signalling via infusion of ACh or ATP during moderate intensity exercise attenuated PE-mediated vasoconstriction (ΔFVC: -13 ± 1 and -19 ± 5%, respectively; P < 0.05 vs. all conditions). Our findings demonstrate that, given a sufficient stimulus, endothelium-dependent sympatholysis remains intact in older adults. Strategies aimed at activating such pathways represent a viable approach for improving sympatholysis and thus tissue blood flow and oxygen delivery in older adults.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Mathew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, USA
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Tanaka H, Tarumi T, Rittweger J. Aging and Physiological Lessons from Master Athletes. Compr Physiol 2019; 10:261-296. [PMID: 31853968 DOI: 10.1002/cphy.c180041] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Sedentary aging is often characterized by physical dysfunction and chronic degenerative diseases. In contrast, masters athletes demonstrate markedly greater physiological function and more favorable levels of risk factors for cardiovascular disease, osteoporosis, frailty, and cognitive dysfunction than their sedentary counterparts. In many cases, age-related deteriorations of physiological functions as well as elevations in risk factors that are typically observed in sedentary adults are substantially attenuated or even absent in masters athletes. Older masters athletes possess greater functional capacity at any given age than their sedentary peers. Impressive profiles of older athletes provide insight into what is possible in human aging and place aging back into the domain of "physiology" rather than under the jurisdiction of "clinical medicine." In addition, these exceptional aging athletes can serve as a role model for the promotion of physical activity at all ages. The study of masters athletes has provided useful insight into the positive example of successful aging. To further establish and propagate masters athletics as a role model for our aging society, future research and action are needed. © 2020 American Physiological Society. Compr Physiol 10:261-296, 2020.
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Affiliation(s)
- Hirofumi Tanaka
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, USA
| | - Takashi Tarumi
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan.,Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
| | - Jörn Rittweger
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany.,Department of Pediatrics and Adolescent Medicine, University of Cologne, Cologne, Germany
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24
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Piil P, Jørgensen TS, Egelund J, Gliemann L, Hellsten Y, Nyberg M. Exercise training reverses an age‐related attenuation in ATP signaling in human skeletal muscle. TRANSLATIONAL SPORTS MEDICINE 2019. [DOI: 10.1002/tsm2.93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Peter Piil
- Department of Nutrition, Exercise and Sports University of Copenhagen Copenhagen Denmark
| | - Tue S. Jørgensen
- Department of Nutrition, Exercise and Sports University of Copenhagen Copenhagen Denmark
- Department of Orthopedics Herlev and Gentofte Hospital Copenhagen Denmark
| | - Jon Egelund
- Department of Nutrition, Exercise and Sports University of Copenhagen Copenhagen Denmark
| | - Lasse Gliemann
- Department of Nutrition, Exercise and Sports University of Copenhagen Copenhagen Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports University of Copenhagen Copenhagen Denmark
| | - Michael Nyberg
- Department of Nutrition, Exercise and Sports University of Copenhagen Copenhagen Denmark
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Racine ML, Dinenno FA. Reduced deformability contributes to impaired deoxygenation-induced ATP release from red blood cells of older adult humans. J Physiol 2019; 597:4503-4519. [PMID: 31310005 DOI: 10.1113/jp278338] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 07/15/2019] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Red blood cells (RBCs) release ATP in response to deoxygenation, which can increase blood flow to help match oxygen supply with tissue metabolic demand. This release of ATP is impaired in RBCs from older adults, but the underlying mechanisms are unknown. In this study, improving RBC deformability in older adults restored deoxygenation-induced ATP release, whereas decreasing RBC deformability in young adults reduced ATP release to the level of that of older adults. In contrast, treating RBCs with a phosphodiesterase 3 inhibitor did not affect ATP release in either age group, possibly due to intact intracellular signalling downstream of deoxygenation as indicated by preserved cAMP and ATP release responses to pharmacological Gi protein activation in RBCs from older adults. These findings are the first to demonstrate that the age-related decrease in RBC deformability is a primary mechanism of impaired deoxygenation-induced ATP release, which may have implications for treating impaired vascular control with advancing age. ABSTRACT In response to haemoglobin deoxygenation, red blood cells (RBCs) release ATP, which binds to endothelial purinergic receptors and stimulates vasodilatation. This ATP release is impaired in RBCs from older vs. young adults, but the underlying mechanisms are unknown. Using isolated RBCs from young (24 ± 1 years) and older (65 ± 2 years) adults, we tested the hypothesis that age-related changes in RBC deformability (Study 1) and cAMP signalling (Study 2) contribute to the impairment. RBC ATP release during normoxia ( P O 2 ∼112 mmHg) and hypoxia ( P O 2 ∼20 mmHg) was quantified with the luciferin-luciferase technique following RBC incubation with Y-27632 (Rho-kinase inhibitor to increase deformability), diamide (cell-stiffening agent), cilostazol (phosphodiesterase 3 inhibitor), or vehicle control. The mean change in RBC ATP release from normoxia to hypoxia in control conditions was significantly impaired in older vs. young (∼50% vs. ∼120%; P < 0.05). RBC deformability was also lower in older vs. young as indicated by a higher RBC transit time (RCTT) measured by blood filtrometry (RCTT: 8.541 ± 0.050 vs. 8.234 ± 0.098 a.u., respectively; P < 0.05). Y-27632 improved RBC deformability (RCTT: 8.228 ± 0.083) and ATP release (111.7 ± 17.2%) in older and diamide decreased RBC deformability (RCTT: 8.955 ± 0.114) and ATP release (67.4 ± 11.8%) in young (P < 0.05), abolishing the age group differences (P > 0.05). Cilostazol did not change ATP release in either age group (P > 0.05), and RBC cAMP and ATP release to pharmacological Gi protein activation was similar in both groups (P > 0.05). We conclude that decreased RBC deformability is a primary contributor to age-related impairments in RBC ATP release, which may have implications for impaired vascular control with advancing age.
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Affiliation(s)
- Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Cardiovascular Research Center, Colorado State University, Fort Collins, CO, 80523, USA
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26
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Hearon CM, Dinenno FA. Escape, lysis, and feedback: endothelial modulation of sympathetic vasoconstriction. Curr Opin Pharmacol 2019; 45:81-86. [PMID: 31170683 DOI: 10.1016/j.coph.2019.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 02/15/2019] [Accepted: 04/01/2019] [Indexed: 12/21/2022]
Abstract
The sympathetic nervous system exerts a vasoconstrictor influence over peripheral vascular beds that is counter-regulated by local vascular signaling mechanisms (i.e. sympathetic escape, sympatholysis, and myoendothelial feedback). The endothelium has emerged as a primary site for the regulation of sympathetic vasoconstriction through highly specialized cellular connections called myoendothelial projections (MEPs) that facilitate electrical coupling of endothelial and vascular smooth muscle cells. Endothelial derived hyperpolarization (EDH) via activation of IKCa channels is an important component of MEP-mediated feedback regulation of sympathetic vasoconstriction in animal models. Recent pharmacological data highlight the unique ability of EDH signaling to attenuate sympathetic vasoconstriction in humans.
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Affiliation(s)
- Christopher M Hearon
- Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, USA; Center for Cardiovascular Research, Colorado State University Fort Collins, CO 80523, USA.
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27
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Groen MB, Knudsen TA, Finsen SH, Pedersen BK, Hellsten Y, Mortensen SP. Reduced skeletal-muscle perfusion and impaired ATP release during hypoxia and exercise in individuals with type 2 diabetes. Diabetologia 2019; 62:485-493. [PMID: 30607464 DOI: 10.1007/s00125-018-4790-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/08/2018] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Plasma ATP is a potent vasodilator and is thought to play a role in the local regulation of blood flow. Type 2 diabetes is associated with reduced tissue perfusion. We aimed to examine whether individuals with type 2 diabetes have reduced plasma ATP concentrations compared with healthy control participants (case-control design). METHODS We measured femoral arterial and venous plasma ATP levels with the intravascular microdialysis technique during normoxia, hypoxia and one-legged knee-extensor exercise (10 W and 30 W) in nine participants with type 2 diabetes and eight control participants. In addition, we infused acetylcholine (ACh), sodium nitroprusside (SNP) and ATP into the femoral artery to assess vascular function and ATP signalling. RESULTS Individuals with type 2 diabetes had a lower leg blood flow (LBF; 2.9 ± 0.1 l/min) compared with the control participants (3.2 ± 0.1 l/min) during exercise (p < 0.05), in parallel with lower venous plasma ATP concentration (205 ± 35 vs 431 ± 72 nmol/l; p < 0.05). During systemic hypoxia, LBF increased from 0.35 ± 0.04 to 0.54 ± 0.06 l/min in control individuals, whereas it did not increase (0.25 ± 0.04 vs 0.31 ± 0.03 l/min) in the those with type 2 diabetes and was lower than in the control individuals (p < 0.05). Hypoxia increased venous plasma ATP levels in both groups (p < 0.05), but the increase was higher in control individuals (90 ± 26 nmol/l) compared to those with type 2 diabetes (18 ± 5 nmol/l). LBF and vascular conductance were lower during ATP (0.15 and 0.4 μmol min-1 [kg leg mass]-1) and ACh (100 μg min-1 [kg leg mass]-1) infusion in individuals with type 2 diabetes compared with the control participants (p < 0.05), whereas there was no difference during SNP infusion. CONCLUSIONS/INTERPRETATION These findings demonstrate that individuals with type 2 diabetes have lower plasma ATP concentrations during exercise and hypoxia compared with control individuals, and this occurs in parallel with lower blood flow. Moreover, individuals with type 2 diabetes have a reduced vasodilatory response to infused ATP. These impairments in the ATP system are both likely to contribute to the reduced tissue perfusion associated with type 2 diabetes. TRIAL REGISTRATION ClinicalTrials.gov NCT02001766.
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Affiliation(s)
- Martin B Groen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Winslowparken 21 3, 5000, Odense, Denmark
| | - Trine A Knudsen
- Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Stine H Finsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Winslowparken 21 3, 5000, Odense, Denmark
| | - Bente K Pedersen
- Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Stefan P Mortensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Winslowparken 21 3, 5000, Odense, Denmark.
- Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark.
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28
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ATP in red blood cells as biomarker for sepsis in humans. Med Hypotheses 2019; 124:84-86. [PMID: 30798924 DOI: 10.1016/j.mehy.2019.02.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/14/2018] [Accepted: 02/02/2019] [Indexed: 12/25/2022]
Abstract
Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to an infection. Due to the lack of causative immune treatment, mortality of sepsis remains at a high level and represents one of the main disease burdens globally. Adenosine 5' triphosphate (ATP) levels in red blood cells (RBC) are modulated by various factors during sepsis, including a decrease in ATP production, an increase in ATP catabolism and alterations in ATP release. Therefore, we hypothesize that intracellular ATP levels in RBC can serve as potential biomarker for sepsis and support sepsis diagnosis. This will facilitate early treatment and could improve the outcome of this serious condition.
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29
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Hearon CM, Richards JC, Racine ML, Luckasen GJ, Larson DG, Dinenno FA. Amplification of endothelium-dependent vasodilatation in contracting human skeletal muscle: role of K IR channels. J Physiol 2018; 597:1321-1335. [PMID: 30506579 DOI: 10.1113/jp276998] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/29/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS In humans, the vasodilatory response to skeletal muscle contraction is mediated in part by activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels serve as electrical amplifiers of endothelium-dependent hyperpolarization (EDH). We found that skeletal muscle contraction amplifies vasodilatation to the endothelium-dependent agonist ACh, whereas there was no change in the vasodilatory response to sodium nitroprusside, an endothelium-independent nitric oxide donor. Blockade of KIR channels reduced the exercise-induced amplification of ACh-mediated vasodilatation. Conversely, pharmacological activation of KIR channels in quiescent muscle via intra-arterial infusion of KCl independently amplified the vasodilatory response to ACh. This study is the first in humans to demonstrate that specific endothelium-dependent vasodilatory signalling is amplified in the vasculature of contracting skeletal muscle and that KIR channels may serve as amplifiers of EDH-like vasodilatory signalling in humans. ABSTRACT The local vasodilatory response to muscle contraction is due in part to the activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels function as 'amplifiers' of endothelium-dependent vasodilators. We tested the hypothesis that contracting muscle selectively amplifies endothelium-dependent vasodilatation via activation of KIR channels. We measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to local intra-arterial infusion of ACh (endothelium-dependent dilator) during resting conditions, handgrip exercise (5% maximum voluntary contraction) or sodium nitroprusside (SNP; endothelium-independent dilator) which served as a high-flow control condition (n = 7, young healthy men and women). Trials were performed before and after blockade of KIR channels via infusion of barium chloride. Exercise augmented peak ACh-mediated vasodilatation (ΔFVC saline: 117 ± 14; exercise: 236 ± 21 ml min-1 (100 mmHg)-1 ; P < 0.05), whereas SNP did not impact ACh-mediated vasodilatation. Blockade of KIR channels attenuated the exercise-induced augmentation of ACh. In eight additional subjects, SNP was administered as the experimental dilator. In contrast to ACh, exercise did not alter SNP-mediated vasodilatation (ΔFVC saline: 158 ± 35; exercise: 121 ± 22 ml min-1 (100 mmHg)-1 ; n.s.). Finally, in a subset of six subjects, direct pharmacological activation of KIR channels in quiescent muscle via infusion of KCl amplified peak ACh-mediated vasodilatation (ΔFVC saline: 97 ± 15, KCl: 142 ± 16 ml min-1 (100 mmHg)-1 ; respectively; P < 0.05). These findings indicate that skeletal muscle contractions selectively amplify endothelium-dependent vasodilatory signalling via activation of KIR channels, and this may be an important mechanism contributing to the normal vasodilatory response to exercise in humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Mathew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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30
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Plasma Nucleotide Dynamics during Exercise and Recovery in Highly Trained Athletes and Recreationally Active Individuals. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4081802. [PMID: 30402475 PMCID: PMC6198572 DOI: 10.1155/2018/4081802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/14/2018] [Accepted: 09/16/2018] [Indexed: 01/04/2023]
Abstract
Circulating plasma ATP is able to regulate local skeletal muscle blood flow and 02 delivery causing considerable vasodilatation during exercise. We hypothesized that sport specialization and specific long-term training stimuli have an impact on venous plasma [ATP] and other nucleotides concentration. Four athletic groups consisting of sprinters (n=11; age range 21–30 yr), endurance-trained athletes (n=16; age range 18–31 yr), futsal players (n=14; age range 18–30 yr), and recreationally active individuals (n=12; age range 22–33 yr) were studied. Venous blood samples were collected at rest, during an incremental treadmill test, and during recovery. Baseline [ATP] was 759±80 nmol·l−1 in competitive athletes and 680±73 nmol·l−1 in controls and increased during exercise by ~61% in competitive athletes and by ~31% in recreationally active participants. We demonstrated a rapid increase in plasma [ATP] at exercise intensities of 83–87% of VO2max in competitive athletes and 94% in controls. Concentrations reported after 30 minutes of recovery were distinct from those obtained preexercise in competitive athletes (P < 0.001) but not in controls (P = 0.61). We found a correlation between total-body skeletal muscle mass and resting and maximal plasma [ATP] in competitive athletes (r=0.81 and r=0.75, respectively). In conclusion, sport specialization is significantly related to plasma [ATP] at rest, during exercise, and during maximal effort. Intensified exercise-induced plasma [ATP] increases may contribute to more effective vessel dilatation during exercise in highly trained athletes than in recreational runners. The most rapid increase in ATP concentration was associated with the respiratory compensation point. No differences between groups of competitive athletes were observed during the recovery period suggesting a similar pattern of response after exercise. Total-body skeletal muscle mass is indirectly related to plasma [ATP] in highly trained athletes.
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31
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Dunford EC, Au JS, Devries MC, Phillips SM, MacDonald MJ. Cardiovascular aging and the microcirculation of skeletal muscle: using contrast-enhanced ultrasound. Am J Physiol Heart Circ Physiol 2018; 315:H1194-H1199. [PMID: 30074839 DOI: 10.1152/ajpheart.00737.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Skeletal muscle is the largest and most important site of capillary-tissue exchange, especially during high-energy demand tasks such as exercise; however, information regarding the role of the microcirculation in maintaining skeletal muscle health is limited. Changes in microcirculatory function, as observed with aging, chronic and cardiovascular diseases, and exercise, likely precede any alterations that arise in larger vessels, although further investigation into these changes is required. One of the main barriers to addressing this knowledge gap is the lack of methodologies for quantifying microvascular function in vivo; the utilization of valid and noninvasive quantification methods would allow the dynamic evaluation of microvascular flow during periods of clinical relevance such as during increased demand for flow (exercise) or decreased demand for flow (disuse). Contrast-enhanced ultrasound (CEUS) is a promising noninvasive technique that has been used for diagnostic medicine and more recently as a complementary research modality to investigate the response of the microcirculation in insulin resistance, diabetes, and aging. To improve the reproducibility of these measurements, our laboratory has optimized the quantification protocol associated with a bolus injection of the contrast agent for research purposes. This brief report outlines the assessment of microvascular flow using the raw time-intensity curve incorporated into gamma variate response modeling. CEUS could be used to compliment any macrovascular assessments to capture a more complete picture of the aging vasculature, and the modified methods presented here provide a template for the general analysis of CEUS within a research setting.
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Affiliation(s)
- Emily C Dunford
- Department of Kinesiology, McMaster University , Hamilton, Ontario , Canada
| | - Jason S Au
- Department of Kinesiology, McMaster University , Hamilton, Ontario , Canada
| | - Michaela C Devries
- Department of Kinesiology, McMaster University , Hamilton, Ontario , Canada
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University , Hamilton, Ontario , Canada
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Racine ML, Crecelius AR, Luckasen GJ, Larson DG, Dinenno FA. Inhibition of Na + /K + -ATPase and K IR channels abolishes hypoxic hyperaemia in resting but not contracting skeletal muscle of humans. J Physiol 2018; 596:3371-3389. [PMID: 29603743 DOI: 10.1113/jp275913] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 03/27/2018] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Increasing blood flow (hyperaemia) to exercising muscle helps match oxygen delivery and metabolic demand. During exercise in hypoxia, there is a compensatory increase in muscle hyperaemia that maintains oxygen delivery and tissue oxygen consumption. Nitric oxide (NO) and prostaglandins (PGs) contribute to around half of the augmented hyperaemia during hypoxic exercise, although the contributors to the remaining response are unknown. In the present study, inhibiting NO, PGs, Na+ /K+ -ATPase and inwardly rectifying potassium (KIR ) channels did not blunt augmented hyperaemia during hypoxic exercise beyond previous observations with NO/PG block alone. Furthermore, although inhibition of only Na+ /K+ -ATPase and KIR channels abolished hyperaemia during hypoxia at rest, it had no effect on augmented hyperaemia during hypoxic exercise. This is the first study in humans to demonstrate that Na+ /K+ -ATPase and KIR channel activation is required for augmented muscle hyperaemia during hypoxia at rest but not during hypoxic exercise, thus providing new insight into vascular control. ABSTRACT Exercise hyperaemia in hypoxia is augmented relative to the same exercise intensity in normoxia. During moderate-intensity handgrip exercise, endothelium-derived nitric oxide (NO) and vasodilating prostaglandins (PGs) contribute to ∼50% of the augmented forearm blood flow (FBF) response to hypoxic exercise (HypEx), although the mechanism(s) underlying the remaining response are unclear. We hypothesized that combined inhibition of NO, PGs, Na+ /K+ -ATPase and inwardly rectifying potassium (KIR ) channels would abolish the augmented hyperaemic response in HypEx. In healthy young adults, FBF responses were measured (Doppler ultrasound) and forearm vascular conductance was calculated during 5 min of rhythmic handgrip exercise at 20% maximum voluntary contraction under regional sympathoadrenal inhibition in normoxia and isocapnic HypEx (O2 saturation ∼80%). Compared to control, combined inhibition of NO, PGs, Na+ /K+ -ATPase and KIR channels (l-NMMA + ketorolac + ouabain + BaCl2; Protocol 1; n = 10) blunted the compensatory increase in FBF during HypEx by ∼50% (29 ± 6 mL min-1 vs. 62 ± 8 mL min-1 , respectively, P < 0.05). By contrast, ouabain + BaCl2 alone (Protocol 2; n = 10) did not affect this augmented hyperaemic response (50 ± 11 mL min-1 vs. 60 ± 13 mL min-1 , respectively, P > 0.05). However, the blocked condition in both protocols abolished the hyperaemic response to hypoxia at rest (P < 0.05). We conclude that activation of Na+ /K+ -ATPase and KIR channels is involved in the hyperaemic response to hypoxia at rest, although it does not contribute to the augmented exercise hyperaemia during hypoxia in humans.
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Affiliation(s)
- Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Anne R Crecelius
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Gary J Luckasen
- Cardiovascular Research Center, Colorado State University, Fort Collins, CO, USA.,Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA.,Cardiovascular Research Center, Colorado State University, Fort Collins, CO, USA
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Mancuso JE, Ristenpart WD. A spike in mechanotransductive adenosine triphosphate release from red blood cells in microfluidic constrictions only occurs with rare donors. Microcirculation 2018; 25:e12439. [PMID: 29325214 PMCID: PMC5947537 DOI: 10.1111/micc.12439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/07/2018] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Wan et al (Proc Natl Acad Sci USA, 105, 2008, 16432) demonstrated that RBCs rapidly and transiently release a spike of 300% more ATP shortly downstream from a short microfluidic constriction where the cells experience a sudden increase in shear stress. More recent work by Cinar et al (Proc Natl Acad Sci USA, 112, 2015, 11783), however, yielded no evidence for a similar spike in ATP release downstream of the constriction. Our aim was to determine whether a transient spike in mechanotransduction is the typical response of RBCs to the sudden onset of increased shear. METHODS We investigate ATP release downstream of a microfluidic constriction for 15 participants using a luciferase-based photoluminescent assay. RESULTS While we observe mechanotransductive ATP release from blood drawn from all donors, we find evidence of a spike in ATP concentration after the microfluidic constriction for only 2 of 15 participants. No clear trends in ATP release are found with respect to the magnitude of the applied shear stress, or to the gender, age, or physical activity (Baecke) index of the donor. CONCLUSIONS In aggregate, all data acquired to date suggest that a spike in mechanotransductive ATP due to a suddenly applied increase in shear stress occurs in blood drawn from only 14% of the population.
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Affiliation(s)
- Jordan E. Mancuso
- Department of Chemical EngineeringUniversity of California DavisDavisCAUSA
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Reilly H, Lane LM, Egaña M. Lack of age-specific influence on leg blood flow during incremental calf plantar-flexion exercise in men and women. Eur J Appl Physiol 2018; 118:989-1001. [PMID: 29502172 DOI: 10.1007/s00421-018-3833-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 02/21/2018] [Indexed: 11/28/2022]
Abstract
PURPOSE Age-related exercising leg blood flow (LBF) responses during dynamic knee-extension exercise and forearm blood flow responses during handgrip exercise are preserved in normally active men but attenuated in activity-matched women. We explored whether these age- and sex-specific effects are also apparent during isometric calf plantar-flexion incremental exercise. METHODS Normally active young men (YM, n = 15, 24 ± 2 years), young women (YW, n = 8, 22 ± 1 years), older men (OM, n = 13, 70 ± 7 years) and older women (OW, n = 10, 64 ± 7 years) were tested. LBF was measured between contractions using venous occlusion plethysmography. RESULTS Peak force obtained was higher (P < 0.05) in men compared with women and in young compared with older individuals. However, peak LBF (YM; 971 ± 328 ml min-1, OM; 985 ± 504 ml min-1, YW; 844 ± 366 ml min-1, OW; 960 ± 244 ml min-1) and peak leg vascular conductance [LVC = LBF/(MAP + hydrostatic pressure)] responses (YM; 6.0 ± 1.8 ml min-1 mmHg-1, OM; 5.5 ± 2.8 ml min-1 mmHg-1, YW; 5.3 ± 2.1 ml min-1 mmHg-1, OW; 5.5 ± 1.6 ml min-1 mmHg-1) were similar among the four groups. Furthermore, the hyperaemic (YM; 8.8 ± 3.7 ml min-1 %Fpeak-1 OM; 8.3 ± 5.4 ml min-1 %Fpeak-1, YW; 8.2 ± 3.5 ml min-1 %Fpeak-1, OW; 9.6 ± 2.2 ml min-1 %Fpeak-1) and vasodilatory responses (YM; 0.053 ± 0.020 ml min-1 mmHg-1 %Fpeak-1, OM; 0.048 ± 0.028 ml min-1 mmHg-1 %Fpeak-1, YW; 0.051 ± 0.019 ml min-1 mmHg-1 %Fpeak-1, OW; 0.055 ± 0.014 ml min-1 mmHg-1 %Fpeak-1) were not different among the four groups. These results were accompanied by similar resting LBF responses among groups and were not affected when data were normalised to estimated leg muscle mass. CONCLUSIONS Our results demonstrate that exercising LBF responses during isometric incremental calf muscle exercise are preserved in older men and women, suggesting that the previously observed age-related attenuations in leg and forearm hyperaemia among women may be muscle-group specific.
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Affiliation(s)
- Heather Reilly
- Department of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Louise M Lane
- Department of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Mikel Egaña
- Department of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland.
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Bentley RF, Walsh JJ, Drouin PJ, Velickovic A, Kitner SJ, Fenuta AM, Tschakovsky ME. Absence of compensatory vasodilation with perfusion pressure challenge in exercise: evidence for and implications of the noncompensator phenotype. J Appl Physiol (1985) 2018; 124:374-387. [PMID: 28706000 DOI: 10.1152/japplphysiol.00952.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Compromising oxygen delivery (O2D) during exercise requires compensatory vasodilatory and/or pressor responses to protect O2D:demand matching. The purpose of the study was to determine whether compensatory vasodilation is absent in some healthy young individuals in the face of a sudden reduction in exercising forearm perfusion pressure and whether this affects the exercise pressor response. Twenty-one healthy young men (21.6 ± 2.0 yr) completed rhythmic forearm exercise at a work rate equivalent to 70% of their own maximal exercise vasodilation. During steady-state exercise, the exercising arm was rapidly adjusted from below to above heart level, resulting in a reduction in forearm perfusion pressure of -30.7 ± 0.9 mmHg. Forearm blood flow (ml/min; brachial artery Doppler and echo ultrasound), mean arterial blood pressure (mmHg; finger photoplethysmography), and exercising forearm venous effluent (antecubital vein catheter) measurements revealed distinct compensatory vasodilatory differences. Thirteen individuals responded with compensatory vasodilation (509 ± 128 vs. 632 ± 136 ml·min-1·100 mmHg-1; P < 0.001), while eight individuals did not (663 ± 165 vs. 667 ± 167 ml·min-1·100 mmHg-1; P = 0.6). Compensatory pressor responses between groups were not different (5.5 ± 5.5 and 9.7 ± 9.5 mmHg; P = 0.2). Forearm blood flow, O2D, and oxygen consumption were all protected in compensators (all P > 0.05) but not in noncompensators, who therefore suffered compromises to exercise performance (6 ± 14 vs. -36 ± 29 N; P = 0.004). Phenotypic differences were not explained by potassium or nitric oxide bioavailability. In conclusion, both compensator and noncompensator vasodilator phenotype responses to a sudden compromise to exercising muscle blood flow are evident. Interindividual differences in the mechanisms governing O2D:demand matching should be considered as factors influencing exercise tolerance. NEW & NOTEWORTHY In healthy young individuals, compromising submaximally exercising muscle perfusion appears to evoke compensatory vasodilation to defend oxygen delivery. Here we report the absence of compensatory vasodilation in 8 of 21 such individuals, despite their vasodilatory capacity and increases in perfusion with increasing exercise intensity being indistinguishable from compensators. The absence of compensation impaired exercise tolerance. These findings suggest that interindividual differences in oxygen delivery:demand matching efficacy affect exercise tolerance and depend on the nature of a delivery:demand matching challenge.
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Affiliation(s)
- Robert F Bentley
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Jeremy J Walsh
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Patrick J Drouin
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Aleksandra Velickovic
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Sarah J Kitner
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Alyssa M Fenuta
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
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Kalsi KK, Chiesa ST, Trangmar SJ, Ali L, Lotlikar MD, González-Alonso J. Mechanisms for the control of local tissue blood flow during thermal interventions: influence of temperature-dependent ATP release from human blood and endothelial cells. Exp Physiol 2018; 102:228-244. [PMID: 27859767 PMCID: PMC5363389 DOI: 10.1113/ep085910] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/14/2016] [Indexed: 12/17/2022]
Abstract
New Findings What is the central question of this study? Skin and muscle blood flow increases with heating and decreases with cooling, but the temperature‐sensitive mechanisms underlying these responses are not fully elucidated. What is the main finding and its importance? We found that local tissue hyperaemia was related to elevations in ATP release from erythrocytes. Increasing intravascular ATP augmented skin and tissue perfusion to levels equal or above thermal hyperaemia. ATP release from isolated erythrocytes was altered by heating and cooling. Our findings suggest that erythrocytes are involved in thermal regulation of blood flow via modulation of ATP release.
Local tissue perfusion changes with alterations in temperature during heating and cooling, but the thermosensitivity of the vascular ATP signalling mechanisms for control of blood flow during thermal interventions remains unknown. Here, we tested the hypotheses that the release of the vasodilator mediator ATP from human erythrocytes, but not from endothelial cells or other blood constituents, is sensitive to both increases and reductions in temperature and that increasing intravascular ATP availability with ATP infusion would potentiate thermal hyperaemia in limb tissues. We first measured blood temperature, brachial artery blood flow and plasma [ATP] during passive arm heating and cooling in healthy men and found that they increased by 3.0 ± 1.2°C, 105 ± 25 ml min−1 °C−1 and twofold, respectively, (all P < 0.05) with heating, but decreased or remained unchanged with cooling. In additional men, infusion of ATP into the brachial artery increased skin and deep tissue perfusion to levels equal or above thermal hyperaemia. In isolated erythrocyte samples exposed to different temperatures, ATP release increased 1.9‐fold from 33 to 39°C (P < 0.05) and declined by ∼50% at 20°C (P < 0.05), but no changes were observed in cultured human endothelial cells, plasma or serum samples. In conclusion, increases in plasma [ATP] and skin and deep tissue perfusion with limb heating are associated with elevations in ATP release from erythrocytes, but not from endothelial cells or other blood constituents. Erythrocyte ATP release is also sensitive to temperature reductions, suggesting that erythrocytes may function as thermal sensors and ATP signalling generators for control of tissue perfusion during thermal interventions.
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Affiliation(s)
- Kameljit K Kalsi
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
| | - Scott T Chiesa
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
| | - Steven J Trangmar
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
| | - Leena Ali
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK.,Department of Anaesthetics, Ealing Hospital NHS Trust, Southall, UK
| | - Makrand D Lotlikar
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK.,Department of Anaesthetics, Ealing Hospital NHS Trust, Southall, UK
| | - José González-Alonso
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, UK
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Grygorczyk R, Orlov SN. Effects of Hypoxia on Erythrocyte Membrane Properties-Implications for Intravascular Hemolysis and Purinergic Control of Blood Flow. Front Physiol 2017; 8:1110. [PMID: 29312010 PMCID: PMC5744585 DOI: 10.3389/fphys.2017.01110] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/14/2017] [Indexed: 01/08/2023] Open
Abstract
Intravascular hemolysis occurs in hereditary, acquired, and iatrogenic hemolytic conditions but it could be also a normal physiological process contributing to intercellular signaling. New evidence suggests that intravascular hemolysis and the associated release of adenosine triphosphate (ATP) may be an important mechanism for in vivo local purinergic signaling and blood flow regulation during exercise and hypoxia. However, the mechanisms that modulate hypoxia-induced RBC membrane fragility remain unclear. Here, we provide an overview of the role of RBC ATP release in the regulation of vascular tone and prevailing assumptions on the putative release mechanisms. We show importance of intravascular hemolysis as a source of ATP for local purinergic regulation of blood flow and discuss processes that regulate membrane propensity to rupture under stress and hypoxia.
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Affiliation(s)
| | - Sergei N. Orlov
- Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
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de Oliveira GV, Morgado M, Conte-Junior CA, Alvares TS. Acute effect of dietary nitrate on forearm muscle oxygenation, blood volume and strength in older adults: A randomized clinical trial. PLoS One 2017; 12:e0188893. [PMID: 29190751 PMCID: PMC5708833 DOI: 10.1371/journal.pone.0188893] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 11/14/2017] [Indexed: 12/24/2022] Open
Abstract
Both recovery time of post-exercise muscle oxygenation and muscle strength decline with aging. Although beetroot consumption has been shown to improve muscle oxygenation and exercise performance in adults, these effects in the elderly has not been addressed. The aim of the present study was to evaluate the effect of a beetroot-based gel (BG) on muscle O2 saturation, blood volume (tHb) and handgrip strength in the elderly in response to handgrip exercise. In a randomized crossover double-blind design, twelve older subjects consumed BG (100 g of beetroot-based gel containing ~ 12 mmol nitrate) or PLA (100 g of nitrate-depleted gel nitrate-depleted). The subjects performed a rhythmic handgrip exercise which consisted of a one 1-min set at 30% of the maximal voluntary contraction (MVC) of each subject, followed by a 1 min recovery. The muscle oxygenation parameters and tHb were continuously monitored by using near-infrared spectroscopy. MVC was evaluated at baseline, immediately after exercise, and 30 min afterwards. The muscle O2 resaturation rate during exercise recovery was greater in the BG when compared to PLA condition (1.43 ± 0.77 vs 1.02 ± 0.48%.s-1; P < 0.05). Significant increase was observed in tHb during exercise recovery (10.25 ± 5.47 vs 6.72 ± 4.55 μM; P < 0.05) and significant reduction of handgrip strength decline was observed 30 min after exercise in BG (- 0.24 ± 0.18 vs—0.39 ± 0.20 N; P < 0.05). In summary, a single dose of a beetroot-based gel speeds up muscle O2 resaturation, increases blood volume and improves recovery of handgrip strength after handgrip exercise in older adults.
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Affiliation(s)
- Gustavo Vieira de Oliveira
- Nutrition and Exercise Metabolism Research Group, Nutrition Institute, Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro, Brazil
| | - Marina Morgado
- Nutrition and Exercise Metabolism Research Group, Nutrition Institute, Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro, Brazil
| | | | - Thiago Silveira Alvares
- Nutrition and Exercise Metabolism Research Group, Nutrition Institute, Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro, Brazil
- Department of Basic Nutrition and Dietetics, Nutrition Institute, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail:
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Hong KS, Kim K. Skeletal muscle contraction-induced vasodilation in the microcirculation. J Exerc Rehabil 2017; 13:502-507. [PMID: 29114523 PMCID: PMC5667595 DOI: 10.12965/jer.1735114.557] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 10/08/2017] [Indexed: 11/22/2022] Open
Abstract
Maximal whole body exercise leads skeletal muscle blood flow to markedly increase to match metabolic demands, a phenomenon termed exercise hyperaemia that is accomplished by increasing vasodilation. However, local vasodilatory mechanisms in response to skeletal muscle contraction remain uncertain. This review highlights metabolic vasodilators released from contracting skeletal muscle, endothelium, or blood cells. As a considerable skeletal muscle vasodilation potentially results in hypotension, sympathetic nerve activity needs to be augmented to elevate cardiac output and blood pressure during dynamic exercise. However, since the enhanced sympathetic vasoconstriction restrains skeletal muscle blood flow, intramuscular arteries have an indispensable ability to blunt sympathetic activity for exercise hyperaemia. In addition, we discuss that mechanical compression of the intramuscular vasculature contributes to causing the initial phase of increasing vasodilation following a single muscle contraction. We have also chosen to focus on conducted (or ascending) electrical signals that evoke vasodilation of proximal feed arteries to elevate blood flow in the microcirculation of skeletal muscle. Endothelial hyperpolarization originating within distal arterioles ascends into the proximal feed arteries, thereby increasing total blood flow in contracting skeletal muscle. This brief review summarizes molecular mechanisms underlying the regulation of skeletal muscle blood flow to a single or sustained muscle contraction.
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Affiliation(s)
- Kwang-Seok Hong
- Robert M. Berne Cardiovascular Research Center, University of Virginia-School of Medicine, Charlottesville, VA, USA
| | - Kijeong Kim
- School of Exercise & Sport Science, College of Natural Sciences, University of Ulsan, Ulsan, Korea
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40
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Piil P, Smith Jørgensen T, Egelund J, Damsgaard R, Gliemann L, Hellsten Y, Nyberg M. Exercise training improves blood flow to contracting skeletal muscle of older men via enhanced cGMP signaling. J Appl Physiol (1985) 2017; 124:109-117. [PMID: 28982945 DOI: 10.1152/japplphysiol.00634.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Physical activity has the potential to offset age-related impairments in the regulation of blood flow and O2 delivery to the exercising muscles; however, the mechanisms underlying this effect of physical activity remain poorly understood. The present study examined the role of cGMP in training-induced adaptations in the regulation of skeletal muscle blood flow and oxidative metabolism during exercise in aging humans. We measured leg hemodynamics and oxidative metabolism during exercise engaging the knee extensor muscles in young [ n = 15, 25 ± 1 (SE) yr] and older ( n = 15, 72 ± 1 yr) subjects before and after a period of aerobic high-intensity exercise training. To determine the role of cGMP signaling, pharmacological inhibition of phosphodiesterase 5 (PDE5) was performed. Before training, inhibition of PDE5 increased ( P < 0.05) skeletal muscle blood flow and O2 uptake during moderate-intensity exercise in the older group; however, these effects of PDE5 inhibition were not detected after training. These findings suggest a role for enhanced cGMP signaling in the training-induced improvement of regulation of blood flow in contracting skeletal muscle of older men. NEW & NOTEWORTHY The present study provides evidence for enhanced cyclic GMP signaling playing an essential role in the improved regulation of blood flow in contracting skeletal muscle of older men with aerobic exercise training.
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Affiliation(s)
- Peter Piil
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Tue Smith Jørgensen
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark.,Department of Orthopedics, Herlev and Gentofte Hospital, Copenhagen, Denmark
| | - Jon Egelund
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Rasmus Damsgaard
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Lasse Gliemann
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Michael Nyberg
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
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Hearon CM, Richards JC, Racine ML, Luckasen GJ, Larson DG, Joyner MJ, Dinenno FA. Sympatholytic effect of intravascular ATP is independent of nitric oxide, prostaglandins, Na + /K + -ATPase and K IR channels in humans. J Physiol 2017; 595:5175-5190. [PMID: 28590059 PMCID: PMC5538228 DOI: 10.1113/jp274532] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/01/2017] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS Intravascular ATP attenuates sympathetic vasoconstriction (sympatholysis) similar to what is observed in contracting skeletal muscle of humans, and may be an important contributor to exercise hyperaemia. Similar to exercise, ATP-mediated vasodilatation occurs via activation of inwardly rectifying potassium channels (KIR ), and synthesis of nitric oxide (NO) and prostaglandins (PG). However, recent evidence suggests that these dilatatory pathways are not obligatory for sympatholysis during exercise; therefore, we tested the hypothesis that the ability of ATP to blunt α1 -adrenergic vasoconstriction in resting skeletal muscle would be independent of KIR , NO, PGs and Na+ /K+ -ATPase activity. Blockade of KIR channels alone or in combination with NO, PGs and Na+ /K+ -ATPase significantly reduced the vasodilatatory response to ATP, although intravascular ATP maintained the ability to attenuate α1 -adrenergic vasoconstriction. This study highlights similarities in the vascular response to ATP and exercise, and further supports a potential role of intravascular ATP in blood flow regulation during exercise in humans. ABSTRACT Exercise and intravascular ATP elicit vasodilatation that is dependent on activation of inwardly rectifying potassium (KIR ) channels, with a modest reliance on nitric oxide (NO) and prostaglandin (PG) synthesis. Both exercise and intravascular ATP attenuate sympathetic α-adrenergic vasoconstriction (sympatholysis). However, KIR channels, NO, PGs and Na+ /K+ -ATPase activity are not obligatory to observe sympatholysis during exercise. To further determine similarities between exercise and intravascular ATP, we tested the hypothesis that inhibition of KIR channels, NO and PG synthesis, and Na+ /K+ -ATPase would not alter the ability of ATP to blunt α1 -adrenergic vasoconstriction. In healthy subjects, we measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to intra-arterial infusion of phenylephrine (PE; α1 -agonist) during ATP or control vasodilatator infusion, before and after KIR channel inhibition alone (barium chloride; n = 7; Protocol 1); NO (l-NMMA) and PG (ketorolac) inhibition alone, or combined NO, PGs, Na+ /K+ -ATPase (ouabain) and KIR channel inhibition (n = 6; Protocol 2). ATP attenuated PE-mediated vasoconstriction relative to adenosine (ADO) and sodium nitroprusside (SNP) (PE-mediated ΔFVC: ATP: -16 ± 2; ADO: -38 ± 6; SNP: -59 ± 6%; P < 0.05 vs. ADO and SNP). Blockade of KIR channels alone or combined with NO, PGs and Na+ /K+ -ATPase, attenuated ATP-mediated vasodilatation (∼35 and ∼60% respectively; P < 0.05 vs. control). However, ATP maintained the ability to blunt PE-mediated vasoconstriction (PE-mediated ΔFVC: KIR blockade alone: -6 ± 5%; combined blockade:-4 ± 14%; P > 0.05 vs. control). These findings demonstrate that intravascular ATP modulates α1 -adrenergic vasoconstriction via pathways independent of KIR channels, NO, PGs and Na+ /K+ -ATPase in humans, consistent with a role for endothelium-derived hyperpolarization in functional sympatholysis.
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Affiliation(s)
- Christopher M. Hearon
- Human Cardiovascular Physiology LaboratoryDepartment of Health and Exercise ScienceFort CollinsCO80523USA
| | - Jennifer C. Richards
- Human Cardiovascular Physiology LaboratoryDepartment of Health and Exercise ScienceFort CollinsCO80523USA
| | - Mathew L. Racine
- Human Cardiovascular Physiology LaboratoryDepartment of Health and Exercise ScienceFort CollinsCO80523USA
| | - Gary J. Luckasen
- Medical Center of the Rockies FoundationUniversity of Colorado HealthLovelandCOUSA
| | - Dennis G. Larson
- Medical Center of the Rockies FoundationUniversity of Colorado HealthLovelandCOUSA
| | | | - Frank A. Dinenno
- Human Cardiovascular Physiology LaboratoryDepartment of Health and Exercise ScienceFort CollinsCO80523USA
- Center for Cardiovascular ResearchColorado State UniversityFort CollinsCO80523USA
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42
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Puthon L, Bouzat P, Robach P, Favre-Juvin A, Doutreleau S, Verges S. Effect of ageing on hypoxic exercise cardiorespiratory, muscle and cerebral oxygenation responses in healthy humans. Exp Physiol 2017; 102:436-447. [DOI: 10.1113/ep085949] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 01/20/2017] [Indexed: 02/04/2023]
Affiliation(s)
- Lara Puthon
- U1042, INSERM, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
- HP2 Laboratory, Université Grenoble Alpes, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
- Acute Care Unit; Grenoble University Hospital; F-38042 Grenoble France
| | - Pierre Bouzat
- Acute Care Unit; Grenoble University Hospital; F-38042 Grenoble France
- Grenoble Institute of Neurosciences; INSERM U836, BP 217 F-38043 Grenoble France
| | - Paul Robach
- U1042, INSERM, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
- HP2 Laboratory, Université Grenoble Alpes, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
- National School for Mountain Sports (ENSM); F-74400 Chamonix France
| | - Anne Favre-Juvin
- U1042, INSERM, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
- HP2 Laboratory, Université Grenoble Alpes, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
| | - Stéphane Doutreleau
- U1042, INSERM, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
- HP2 Laboratory, Université Grenoble Alpes, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
| | - Samuel Verges
- U1042, INSERM, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
- HP2 Laboratory, Université Grenoble Alpes, Building Jean Roget; Faculty of Medicine; F-38042 Grenoble France
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43
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Richards JC, Crecelius AR, Larson DG, Luckasen GJ, Dinenno FA. Impaired peripheral vasodilation during graded systemic hypoxia in healthy older adults: role of the sympathoadrenal system. Am J Physiol Heart Circ Physiol 2017; 312:H832-H841. [PMID: 28159810 DOI: 10.1152/ajpheart.00794.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 02/01/2023]
Abstract
Systemic hypoxia is a physiological and pathophysiological stress that activates the sympathoadrenal system and, in young adults, leads to peripheral vasodilation. We tested the hypothesis that peripheral vasodilation to graded systemic hypoxia is impaired in older healthy adults and that this age-associated impairment is due to attenuated β-adrenergic mediated vasodilation and elevated α-adrenergic vasoconstriction. Forearm blood flow was measured (Doppler ultrasound), and vascular conductance (FVC) was calculated in 12 young (24 ± 1 yr) and 10 older (63 ± 2 yr) adults to determine the local dilatory responses to graded hypoxia (90, 85, and 80% O2 saturations) in control conditions, following local intra-arterial blockade of β-receptors (propranolol), and combined blockade of α- and β-receptors (phentolamine + propranolol). Under control conditions, older adults exhibited impaired vasodilation to hypoxia compared with young participants at all levels of hypoxia (peak ΔFVC at 80% [Formula: see text] = 4 ± 6 vs. 35 ± 8%; P < 0.01). During β-blockade, older adults actively constricted at 85 and 80% [Formula: see text] (peak ΔFVC at 80% [Formula: see text] = -13 ± 6%; P < 0.05 vs. control), whereas the response in the young was not significantly impacted (peak ΔFVC = 28 ± 8%). Combined α- and β-blockade increased the dilatory response to hypoxia in young adults; however, older adults failed to significantly vasodilate (peak ΔFVC at 80% [Formula: see text]= 12 ± 11% vs. 58 ± 11%; P < 0.05). Our findings indicate that peripheral vasodilation to graded systemic hypoxia is significantly impaired in older adults, which cannot be fully explained by altered sympathoadrenal control of vascular tone. Thus, the impairment in hypoxic vasodilation is likely due to attenuated local vasodilatory and/or augmented vasoconstrictor signaling with age.NEW & NOTEWORTHY We found that the lack of peripheral vasodilation during graded systemic hypoxia with aging is not mediated by the sympathoadrenal system, strongly implicating local vascular control mechanisms in this impairment. Understanding these mechanisms may lead to therapeutic advances for improving tissue blood flow and oxygen delivery in aging and disease.
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Affiliation(s)
- Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado; and
| | - Anne R Crecelius
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado; and
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, Colorado
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, Colorado
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado; and
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Zempo H, Isobe M, Naito H. Link between blood flow and muscle protein metabolism in elderly adults. ACTA ACUST UNITED AC 2017. [DOI: 10.7600/jpfsm.6.25] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Hirofumi Zempo
- Japan Society for the Promotion of Science
- Graduate School of Health and Sports Science, Juntendo University
| | - Mitsuaki Isobe
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Hisashi Naito
- Graduate School of Health and Sports Science, Juntendo University
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45
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Brose SA, Golovko SA, Golovko MY. Fatty Acid Biosynthesis Inhibition Increases Reduction Potential in Neuronal Cells under Hypoxia. Front Neurosci 2016; 10:546. [PMID: 27965531 PMCID: PMC5127813 DOI: 10.3389/fnins.2016.00546] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/11/2016] [Indexed: 12/12/2022] Open
Abstract
Recently, we have reported a novel neuronal specific pathway for adaptation to hypoxia through increased fatty acid (FA) biosynthesis followed by esterification into lipids. However, the biological role of this pathway under hypoxia remains to be elucidated. In the presented study, we have tested our hypothesis that activation of FA synthesis maintains reduction potential and reduces lactoacidosis in neuronal cells under hypoxia. To address this hypothesis, we measured the effect of FA synthesis inhibition on [Formula: see text]/NAD+ and [Formula: see text]/NADP+ ratios, and lactic acid levels in neuronal SH-SY5Y cells exposed to normoxic and hypoxic conditions. FA synthesis inhibitors, TOFA (inhibits Acetyl-CoA carboxylase) and cerulenin (inhibits FA synthase), increased [Formula: see text]/NAD+ and [Formula: see text]/NADP+ ratios under hypoxia. Further, FA synthesis inhibition increased lactic acid under both normoxic and hypoxic conditions, and caused cytotoxicity under hypoxia but not normoxia. These results indicate that FA may serve as hydrogen acceptors under hypoxia, thus supporting oxidation reactions including anaerobic glycolysis. These findings may help to identify a radically different approach to attenuate hypoxia related pathophysiology in the nervous system including stroke.
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Affiliation(s)
- Stephen A Brose
- Department of Biomedical Sciences, University of North Dakota Grand Forks, ND, USA
| | - Svetlana A Golovko
- Department of Biomedical Sciences, University of North Dakota Grand Forks, ND, USA
| | - Mikhail Y Golovko
- Department of Biomedical Sciences, University of North Dakota Grand Forks, ND, USA
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46
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Hearon CM, Kirby BS, Luckasen GJ, Larson DG, Dinenno FA. Endothelium-dependent vasodilatory signalling modulates α 1 -adrenergic vasoconstriction in contracting skeletal muscle of humans. J Physiol 2016; 594:7435-7453. [PMID: 27561916 DOI: 10.1113/jp272829] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/17/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS 'Functional sympatholysis' describes the ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction, and is critical to ensure proper blood flow and oxygen delivery to metabolically active skeletal muscle. The signalling mechanism responsible for sympatholysis in healthy humans is unknown. Evidence from animal models has identified endothelium-derived hyperpolarization (EDH) as a potential mechanism capable of attenuating sympathetic vasoconstriction. In this study, increasing endothelium-dependent signalling during exercise significantly enhanced the ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction in humans. This is the first study in humans to identify endothelium-dependent regulation of sympathetic vasoconstriction in contracting skeletal muscle, and specifically supports a role for EDH-like vasodilatory signalling. Impaired functional sympatholysis is a common feature of cardiovascular ageing, hypertension and heart failure, and thus identifying fundamental mechanisms responsible for sympatholysis is clinically relevant. ABSTRACT Stimulation of α-adrenoceptors elicits vasoconstriction in resting skeletal muscle that is blunted during exercise in an intensity-dependent manner. In humans, the underlying mechanisms remain unclear. We tested the hypothesis that stimulating endothelium-dependent vasodilatory signalling will enhance the ability of contracting skeletal muscle to blunt α1 -adrenergic vasoconstriction. Changes in forearm vascular conductance (FVC; Doppler ultrasound, brachial intra-arterial pressure via catheter) to local intra-arterial infusion of phenylephrine (PE; α1 -adrenoceptor agonist) were calculated during (1) infusion of the endothelium-dependent vasodilators acetylcholine (ACh) and adenosine triphosphate (ATP), the endothelium-independent vasodilator (sodium nitroprusside, SNP), or potassium chloride (KCl) at rest; (2) mild or moderate intensity handgrip exercise; and (3) combined mild exercise + ACh, ATP, SNP, or KCl infusions in healthy adults. Robust vasoconstriction to PE was observed during vasodilator infusion alone and mild exercise, and this was blunted during moderate intensity exercise (ΔFVC: -34 ± 4 and -34 ± 3 vs. -13 ± 2%, respectively, P < 0.05). Infusion of ACh or ATP during mild exercise significantly attenuated PE vasoconstriction similar to levels observed during moderate exercise (ACh: -3 ± 4; ATP: -18 ± 4%). In contrast, infusion of SNP or KCl during mild exercise did not attenuate PE-mediated vasoconstriction (-32 ± 5 and -46 ± 3%). To further study the role of endothelium-dependent hyperpolarization (EDH), ACh trials were repeated with combined nitric oxide synthase and cyclooxygenase inhibition. Here, PE-mediated vasoconstriction was blunted at rest (blockade: -20 ± 5 vs. CONTROL -31 ± 3% vs.; P < 0.05) and remained blunted during exercise (blockade: -15 ± 5 vs. CONTROL -14 ± 5%). We conclude that stimulation of EDH-like vasodilatation can blunt α1 -adrenergic vasoconstriction in contracting skeletal muscle of humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Brett S Kirby
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, 80538, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, 80538, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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47
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Trinity JD, Broxterman RM, Richardson RS. Regulation of exercise blood flow: Role of free radicals. Free Radic Biol Med 2016; 98:90-102. [PMID: 26876648 PMCID: PMC4975999 DOI: 10.1016/j.freeradbiomed.2016.01.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/07/2016] [Accepted: 01/21/2016] [Indexed: 02/07/2023]
Abstract
During exercise, oxygen and nutrient rich blood must be delivered to the active skeletal muscle, heart, skin, and brain through the complex and highly regulated integration of central and peripheral hemodynamic factors. Indeed, even minor alterations in blood flow to these organs have profound consequences on exercise capacity by modifying the development of fatigue. Therefore, the fine-tuning of blood flow is critical for optimal physical performance. At the level of the peripheral circulation, blood flow is regulated by a balance between the mechanisms responsible for vasodilation and vasoconstriction. Once thought of as toxic by-products of in vivo chemistry, free radicals are now recognized as important signaling molecules that exert potent vasoactive responses that are dependent upon the underlying balance between oxidation-reduction reactions or redox balance. Under normal healthy conditions with low levels of oxidative stress, free radicals promote vasodilation, which is attenuated with exogenous antioxidant administration. Conversely, with advancing age and disease where background oxidative stress is elevated, an exercise-induced increase in free radicals can further shift the redox balance to a pro-oxidant state, impairing vasodilation and attenuating blood flow. Under these conditions, exogenous antioxidants improve vasodilatory capacity and augment blood flow by restoring an "optimal" redox balance. Interestingly, while the active skeletal muscle, heart, skin, and brain all have unique functions during exercise, the mechanisms by which free radicals contribute to the regulation of blood flow is remarkably preserved across each of these varied target organs.
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Affiliation(s)
- Joel D Trinity
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Internal Medicine, Division of Geriatric, University of Utah, Salt Lake City, UT, USA.
| | - Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Internal Medicine, Division of Geriatric, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Internal Medicine, Division of Geriatric, University of Utah, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
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48
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Semyachkina-Glushkovskaya O, Borisova E, Abakumov M, Gorin D, Avramov L, Fedosov I, Namykin A, Abdurashitov A, Serov A, Pavlov A, Zinchenko E, Lychagov V, Navolokin N, Shirokov A, Maslyakova G, Zhu D, Luo Q, Chekhonin V, Tuchin V, Kurths J. The Stress and Vascular Catastrophes in Newborn Rats: Mechanisms Preceding and Accompanying the Brain Hemorrhages. Front Physiol 2016; 7:210. [PMID: 27378933 PMCID: PMC4906045 DOI: 10.3389/fphys.2016.00210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/22/2016] [Indexed: 11/17/2022] Open
Abstract
In this study, we analyzed the time-depended scenario of stress response cascade preceding and accompanying brain hemorrhages in newborn rats using an interdisciplinary approach based on: a morphological analysis of brain tissues, coherent-domain optical technologies for visualization of the cerebral blood flow, monitoring of the cerebral oxygenation and the deformability of red blood cells (RBCs). Using a model of stress-induced brain hemorrhages (sound stress, 120 dB, 370 Hz), we studied changes in neonatal brain 2, 4, 6, 8 h after stress (the pre-hemorrhage, latent period) and 24 h after stress (the post-hemorrhage period). We found that latent period of brain hemorrhages is accompanied by gradual pathological changes in systemic, metabolic, and cellular levels of stress. The incidence of brain hemorrhages is characterized by a progression of these changes and the irreversible cell death in the brain areas involved in higher mental functions. These processes are realized via a time-depended reduction of cerebral venous blood flow and oxygenation that was accompanied by an increase in RBCs deformability. The significant depletion of the molecular layer of the prefrontal cortex and the pyramidal neurons, which are crucial for associative learning and attention, is developed as a consequence of homeostasis imbalance. Thus, stress-induced processes preceding and accompanying brain hemorrhages in neonatal period contribute to serious injuries of the brain blood circulation, cerebral metabolic activity and structural elements of cognitive function. These results are an informative platform for further studies of mechanisms underlying stress-induced brain hemorrhages during the first days of life that will improve the future generation's health.
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Affiliation(s)
- Oxana Semyachkina-Glushkovskaya
- Department of Physiology of Human and Animals, Saratov State UniversitySaratov, Russia; Huazhong University of Science and TechnologyWuhan, China
| | - Ekaterina Borisova
- Laboratory of Biophotonics, Institute of Electronics, Bulgarian Academy of Sciences Sofia, Bulgaria
| | - Maxim Abakumov
- Medico-Biological Department, Russian National Research Medical University Moscow, Russia
| | - Dmitry Gorin
- Department of Nanotechnology, Saratov State University Saratov, Russia
| | - Latchezar Avramov
- Laboratory of Biophotonics, Institute of Electronics, Bulgarian Academy of Sciences Sofia, Bulgaria
| | - Ivan Fedosov
- Department of Physics, Saratov State University Saratov, Russia
| | - Anton Namykin
- Department of Physics, Saratov State University Saratov, Russia
| | | | - Alexander Serov
- Department of Physiology of Human and Animals, Saratov State University Saratov, Russia
| | - Alexey Pavlov
- Department of Electrical Engineering and Electronics, Saratov State Technical University Saratov, Russia
| | - Ekaterina Zinchenko
- Department of Physiology of Human and Animals, Saratov State University Saratov, Russia
| | - Vlad Lychagov
- Department of Physics, Saratov State University Saratov, Russia
| | - Nikita Navolokin
- Department of Pathological Anatomy, Saratov State Medical University Saratov, Russia
| | - Alexander Shirokov
- Saratov Research Center, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences (IBPPM RAS) Saratov, Russia
| | - Galina Maslyakova
- Department of Pathological Anatomy, Saratov State Medical University Saratov, Russia
| | - Dan Zhu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology Wuhan, China
| | - Qingming Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology Wuhan, China
| | - Vladimir Chekhonin
- Medico-Biological Department, Russian National Research Medical University Moscow, Russia
| | - Valery Tuchin
- Huazhong University of Science and TechnologyWuhan, China; Department of Physics, Saratov State UniversitySaratov, Russia; Laboratory of Biophotonics, Science Department, Tomsk State UniversityTomsk, Russia
| | - Jürgen Kurths
- Huazhong University of Science and TechnologyWuhan, China; Department of Physics, Humboldt UniversityBerlin, Germany; Research Domain Transdisciplinary Concepts and Methods, Potsdam Institute for Climate Impact ResearchPotsdam, Germany
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49
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Hearon CM, Dinenno FA. Regulation of skeletal muscle blood flow during exercise in ageing humans. J Physiol 2015; 594:2261-73. [PMID: 26332887 DOI: 10.1113/jp270593] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/13/2015] [Indexed: 12/12/2022] Open
Abstract
The regulation of skeletal muscle blood flow and oxygen delivery to contracting skeletal muscle is complex and involves the mechanical effects of muscle contraction; local metabolic, red blood cell and endothelium-derived substances; and the sympathetic nervous system (SNS). With advancing age in humans, skeletal muscle blood flow is typically reduced during dynamic exercise and this is due to a lower vascular conductance, which could ultimately contribute to age-associated reductions in aerobic exercise capacity, a primary predictor of mortality in both healthy and diseased ageing populations. Recent findings have highlighted the contribution of endothelium-derived substances to blood flow control in contracting muscle of older adults. With advancing age, impaired nitric oxide availability due to scavenging by reactive oxygen species, in conjunction with elevated vasoconstrictor signalling via endothelin-1, reduces the local vasodilatory response to muscle contraction. Additionally, ageing impairs the ability of contracting skeletal muscle to blunt sympathetic vasoconstriction (i.e. 'functional sympatholysis'), which is critical for the proper regulation of tissue blood flow distribution and oxygen delivery, and could further reduce skeletal muscle perfusion during high intensity and/or large muscle mass exercise in older adults. We propose that initiation of endothelium-dependent hyperpolarization is the underlying signalling event necessary to properly modulate sympathetic vasoconstriction in contracting muscle, and that age-associated impairments in red blood cell adenosine triphosphate release and stimulation of endothelium-dependent vasodilatation may explain impairments in both local vasodilatation and functional sympatholysis with advancing age in humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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50
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Nyberg M, Piil P, Egelund J, Sprague RS, Mortensen SP, Hellsten Y. Effect of PDE5 inhibition on the modulation of sympathetic α-adrenergic vasoconstriction in contracting skeletal muscle of young and older recreationally active humans. Am J Physiol Heart Circ Physiol 2015; 309:H1867-75. [PMID: 26432842 DOI: 10.1152/ajpheart.00653.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/28/2015] [Indexed: 11/22/2022]
Abstract
Aging is associated with an altered regulation of blood flow to contracting skeletal muscle; however, the precise mechanisms remain unclear. We recently demonstrated that inhibition of cGMP-binding phosphodiesterase 5 (PDE5) increased blood flow to contracting skeletal muscle of older but not young human subjects. Here we examined whether this effect of PDE5 inhibition was related to an improved ability to blunt α-adrenergic vasoconstriction (functional sympatholysis) and/or improved efficacy of local vasodilator pathways. A group of young (23 ± 1 yr) and a group of older (72 ± 1 yr) male subjects performed knee-extensor exercise in a control setting and following intake of the highly selective PDE5 inhibitor sildenafil. During both conditions, exercise was performed without and with arterial tyramine infusion to evoke endogenous norepinephrine release and consequently stimulation of α1- and α2-adrenergic receptors. The level of the sympatholytic compound ATP was measured in venous plasma by use of the microdialysis technique. Sildenafil increased (P < 0.05) vascular conductance during exercise in the older group, but tyramine infusion reduced (P < 0.05) this effect by 38 ± 9%. Similarly, tyramine reduced (P < 0.05) the vasodilation induced by arterial infusion of a nitric oxide (NO) donor by 54 ± 9% in the older group, and this effect was not altered by sildenafil. Venous plasma [ATP] did not change with PDE5 inhibition in the older subjects during exercise. Collectively, PDE5 inhibition in older humans was not associated with an improved ability for functional sympatholysis. An improved efficacy of the NO system may be one mechanism underlying the effect of PDE5 inhibition on exercise hyperemia in aging.
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Affiliation(s)
- Michael Nyberg
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark;
| | - Peter Piil
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jon Egelund
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Randy S Sprague
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri
| | - Stefan P Mortensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark; and The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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