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Kang JW, Kim KT, Park JW, Lee SJ. Classification of deep vein thrombosis stages using convolutional neural network of electromyogram with vibrotactile stimulation toward developing an early diagnostic tool: A preliminary study on a pig model. PLoS One 2023; 18:e0281219. [PMID: 36730258 PMCID: PMC9894458 DOI: 10.1371/journal.pone.0281219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/18/2023] [Indexed: 02/03/2023] Open
Abstract
Deep vein thrombosis (DVT) can lead to life-threatening disorders; however, it can only be recognized after its symptom appear. This study proposed a novel method that can detect the early stage of DVT using electromyography (EMG) signals with vibration stimuli using the convolutional neural networks (CNN) algorithm. The feasibility of the method was tested with eight legs before and after the surgical induction of DVT at nine-time points. Furthermore, perfusion pressure (PP), intracompartmental pressure (IP), and shear elastic modulus (SEM) of the tibialis anterior were also collected. In the proposed method, principal component analysis (PCA) and CNN were used to analyze the EMG data and classify it before and after the DVT stages. The cross-validation was performed in two strategies. One is for each leg and the other is the leave-one-leg-out (LOLO), test without any predicted information, for considering the practical diagnostic tool. The results showed that PCA-CNN can classify before and after DVT stages with an average accuracy of 100% (each leg) and 68.4±20.5% (LOLO). Moreover, all-time points (before induction of DVT and eight-time points after DVT) were classified with an average accuracy of 72.0±11.9% which is substantially higher accuracy than the chance levels (11% for 9-class classification). Based on the experimental results in the pig model, the proposed CNN-based method can classify the before- and after-DVT stages with high accuracy. The experimental results can provide a basis for further developing an early diagnostic tool for DVT using only EMG signals with vibration stimuli.
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Affiliation(s)
- Jong Woo Kang
- Department of Orthopaedic Surgery, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - Keun-Tae Kim
- Bionics Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Jong Woong Park
- Department of Orthopaedic Surgery, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Song Joo Lee
- Bionics Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
- * E-mail:
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2
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Palmo T, Abbasi BA, Chanana N, Sharma K, Faruq M, Thinlas T, Abdin MZ, Pasha Q. The EDN1 Missense Variant rs5370 G > T Regulates Adaptation and Maladaptation under Hypobaric Hypoxia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:11174. [PMID: 36141455 PMCID: PMC9517604 DOI: 10.3390/ijerph191811174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/28/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
Endothelin 1 (EDN1) encodes a potent endogenous vasoconstrictor, ET1, to maintain vascular homeostasis and redistribution of tissue blood flow during exercise. One of the EDN1 missense polymorphisms, rs5370 G/T, has strongly been associated with cardiopulmonary diseases. This study investigated the impact of rs5370 polymorphism in high-altitude pulmonary oedema (HAPE) disorder or maladaptation and adaptation physiology in a well-characterized case-control study of high-altitude and low-altitude populations comprising 310 samples each of HAPE-patients, HAPE-free controls and native highlanders. The rs5370 polymorphism was genotyped, and the gene expression and plasma level of EDN1 were evaluated. The functional relevance of each allele was investigated in the human embryonic kidney 293 cell line after exposure to hypoxia and computationally. The T allele was significantly more prevalent in HAPE-p compared to HAPE-f and HLs. The EDN1 gene expression and ET1 bio-level were significantly elevated in HAPE-p compared to controls. Compared to the G allele, the T allele was significantly associated with elevated levels of ET-1 in all three study groups and cells exposed to hypoxia. The in silico studies further confirmed the stabilizing effect of the T allele on the structural integrity and function of ET1 protein. The ET1 rs5370 T allele is associated with an increased concentration of ET-1 in vivo and in vitro, establishing it as a potent marker in the adaptation/maladaptation physiology under the high-altitude environment. This could also be pertinent in endurance exercises at high altitudes.
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Affiliation(s)
- Tsering Palmo
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India
- Department of Biotechnology, Jamia Hamdard, New Delhi 110062, India
| | - Bilal Ahmed Abbasi
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India
| | - Neha Chanana
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India
| | - Kavita Sharma
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India
| | - Tashi Thinlas
- Sonam Norboo Memorial Hospital, Leh 194101, Ladakh, India
| | - Malik Z. Abdin
- Department of Biotechnology, Jamia Hamdard, New Delhi 110062, India
| | - Qadar Pasha
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India
- Institute of Hypoxia Research, New Delhi 110067, India
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Giuriato G, Venturelli M, Matias A, Soares EMKVK, Gaetgens J, Frederick KA, Ives SJ. Capsaicin and Its Effect on Exercise Performance, Fatigue and Inflammation after Exercise. Nutrients 2022; 14:232. [PMID: 35057413 PMCID: PMC8778706 DOI: 10.3390/nu14020232] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/30/2021] [Accepted: 01/02/2022] [Indexed: 01/27/2023] Open
Abstract
Capsaicin (CAP) activates the transient receptor potential vanilloid 1 (TRPV1) channel on sensory neurons, improving ATP production, vascular function, fatigue resistance, and thus exercise performance. However, the underlying mechanisms of CAP-induced ergogenic effects and fatigue-resistance, remain elusive. To evaluate the potential anti-fatigue effects of CAP, 10 young healthy males performed constant-load cycling exercise time to exhaustion (TTE) trials (85% maximal work rate) after ingestion of placebo (PL; fiber) or CAP capsules in a blinded, counterbalanced, crossover design, while cardiorespiratory responses were monitored. Fatigue was assessed with the interpolated twitch technique, pre-post exercise, during isometric maximal voluntary contractions (MVC). No significant differences (p > 0.05) were detected in cardiorespiratory responses and self-reported fatigue (RPE scale) during the time trial or in TTE (375 ± 26 and 327 ± 36 s, respectively). CAP attenuated the reduction in potentiated twitch (PL: -52 ± 6 vs. CAP: -42 ± 11%, p = 0.037), and tended to attenuate the decline in maximal relaxation rate (PL: -47 ± 33 vs. CAP: -29 ± 68%, p = 0.057), but not maximal rate of force development, MVC, or voluntary muscle activation. Thus, CAP might attenuate neuromuscular fatigue through alterations in afferent signaling or neuromuscular relaxation kinetics, perhaps mediated via the sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) pumps, thereby increasing the rate of Ca2+ reuptake and relaxation.
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Affiliation(s)
- Gaia Giuriato
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (G.G.); (M.V.)
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
| | - Massimo Venturelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (G.G.); (M.V.)
- Department of Internal Medicine, University of Utah, Salt Lake City, UT 84132, USA
| | - Alexs Matias
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
| | - Edgard M. K. V. K. Soares
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
- Study Group on Exercise and Physical Activity Physiology and Epidemiology, Exercise Physiology Laboratory, Faculty of Physical Education, University of Brasilia—UnB, Brasilia 70910-900, Brazil
| | - Jessica Gaetgens
- Department of Chemistry, Skidmore College, Saratoga Springs, NY 12866, USA; (J.G.); (K.A.F.)
| | - Kimberley A. Frederick
- Department of Chemistry, Skidmore College, Saratoga Springs, NY 12866, USA; (J.G.); (K.A.F.)
| | - Stephen J. Ives
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
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4
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Bergia RE, Campbell WW, Roseguini BT, Kim JE. A high-protein meal does not improve blood pressure or vasoactive biomarker responses to acute exercise in humans. Nutr Res 2020; 81:97-107. [PMID: 32949918 DOI: 10.1016/j.nutres.2020.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 07/09/2020] [Accepted: 08/05/2020] [Indexed: 11/19/2022]
Abstract
Blood pressure (BP) responses to exercise yield prognostic information beyond resting BP. While habitual higher dietary protein intake is associated with reduced resting BP, few studies have assessed the impact of high-protein meals on acute BP and vasoactive biomarker responses to exercise. To test the hypothesis that consuming a higher-protein, lower fat meal (HP; 30 g protein, 17 g fat, 52 g carbohydrate) would attenuate the BP response to exercise and result in a more robust post-exercise hypotensive response compared to a lower-protein, higher-fat meal (LP; 13 g protein, 25 g fat, 54 g carbohydrate), we recruited 31 pre-hypertensive subjects to complete this randomized, double-blind, cross-over acute feeding study. One hundred sixty-five minutes after consuming the test HP or LP meal, subjects exercised on a cycle ergometer at 70% VO2 max for 30 minutes. Blood pressure was measured prior to the meal and periodically before, during, and after exercise for a 315-minute period. Blood samples were periodically collected to quantify plasma arginine, arginine metabolites (asymmetric dimethylarginine, symmetric dimethylarginine; ADMA, SDMA), endothelin-1, nitrates, and nitrites in a subset of subjects (n = 15) as shown in Supplemental Table S1. Consuming the HP meal did not influence the BP responses to exercise, including the post-exercise return to baseline BP or systolic BP area under the curve. While the HP meal resulted in greater postprandial plasma arginine concentrations, ADMA, SDMA, endothelin-1, nitrates, and nitrites were unaltered. These results suggest that consuming a higher-protein, lower-fat meal does not influence BP or vasoactive biomarker responses to exercise compared to a lower-protein, higher-fat meal.
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Affiliation(s)
- Robert E Bergia
- Department of Nutrition Science, Purdue University, 700 West State St, West Lafayette, IN 47907
| | - Wayne W Campbell
- Department of Nutrition Science, Purdue University, 700 West State St, West Lafayette, IN 47907.
| | - Bruno T Roseguini
- Department of Health & Kinesiology, Purdue University, 800 W Stadium Ave, West Lafayette, IN 47907
| | - Jung Eun Kim
- Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
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5
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Jones NK, Stewart K, Czopek A, Menzies RI, Thomson A, Moran CM, Cairns C, Conway BR, Denby L, Livingstone DEW, Wiseman J, Hadoke PW, Webb DJ, Dhaun N, Dear JW, Mullins JJ, Bailey MA. Endothelin-1 Mediates the Systemic and Renal Hemodynamic Effects of GPR81 Activation. Hypertension 2020; 75:1213-1222. [PMID: 32200679 PMCID: PMC7176350 DOI: 10.1161/hypertensionaha.119.14308] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Supplemental Digital Content is available in the text. GPR81 (G-protein-coupled receptor 81) is highly expressed in adipocytes, and activation by the endogenous ligand lactate inhibits lipolysis. GPR81 is also expressed in the heart, liver, and kidney, but roles in nonadipose tissues are poorly defined. GPR81 agonists, developed to improve blood lipid profile, might also provide insights into GPR81 physiology. Here, we assessed the blood pressure and renal hemodynamic responses to the GPR81 agonist, AZ′5538. In male wild-type mice, intravenous AZ′5538 infusion caused a rapid and sustained increase in systolic and diastolic blood pressure. Renal artery blood flow, intrarenal tissue perfusion, and glomerular filtration rate were all significantly reduced. AZ′5538 had no effect on blood pressure or renal hemodynamics in Gpr81−/− mice. Gpr81 mRNA was expressed in renal artery vascular smooth muscle, in the afferent arteriole, in glomerular and medullary perivascular cells, and in pericyte-like cells isolated from kidney. Intravenous AZ′5538 increased plasma ET-1 (endothelin 1), and pretreatment with BQ123 (endothelin-A receptor antagonist) prevented the pressor effects of GPR81 activation, whereas BQ788 (endothelin-B receptor antagonist) did not. Renal ischemia-reperfusion injury, which increases renal extracellular lactate, increased the renal expression of genes encoding ET-1, KIM-1 (Kidney Injury Molecule 1), collagen type 1-α1, TNF-α (tumor necrosis factor-α), and F4/80 in wild-type mice but not in Gpr81−/− mice. In summary, activation of GPR81 in vascular smooth muscle and perivascular cells regulates renal hemodynamics, mediated by release of the potent vasoconstrictor ET-1. This suggests that lactate may be a paracrine regulator of renal blood flow, particularly relevant when extracellular lactate is high as occurs during ischemic renal disease.
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Affiliation(s)
- Natalie K Jones
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Kevin Stewart
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Alicja Czopek
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Robert I Menzies
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Adrian Thomson
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Carmel M Moran
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Carolynn Cairns
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Bryan R Conway
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Laura Denby
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Dawn E W Livingstone
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - John Wiseman
- Discovery Sciences, IMED Biotech Unit, AstraZeneca R&D Gothenburg, Sweden (J.W.)
| | - Patrick W Hadoke
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - David J Webb
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Neeraj Dhaun
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - James W Dear
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - John J Mullins
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
| | - Matthew A Bailey
- From the University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Scotland, United Kingdom (N.K.J., K.S., A.C., R.I.M., A.T., C.M.M., C.C., B.R.C., L.D., D.E.W.L., P.W.H., D.J.W., N.D., J.W.D., J.J.M., M.A.B.)
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6
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Lane SL, Doyle AS, Bales ES, Houck JA, Lorca RA, Moore LG, Julian CG. Peroxisome proliferator-activated receptor gamma blunts endothelin-1-mediated contraction of the uterine artery in a murine model of high-altitude pregnancy. FASEB J 2020; 34:4283-4292. [PMID: 31970838 DOI: 10.1096/fj.201902264rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 01/02/2020] [Accepted: 01/08/2020] [Indexed: 01/12/2023]
Abstract
The environmental hypoxia of high altitude (HA) increases the incidence of intrauterine growth restriction (IUGR) approximately threefold. The peroxisome proliferator-activated receptor γ (PPAR-γ), a ligand-activated nuclear receptor that promotes vasorelaxation by increasing nitric oxide and downregulating endothelin-1 (ET-1) production, has been implicated in IUGR. Based on our prior work indicating that pharmacologic activation of the PPARγ pathway protects against hypoxia-associated IUGR, we used an experimental murine model to determine whether such effects may be attributed to vasodilatory effects in the uteroplacental circulation. Using wire myography, ex vivo vasoreactivity studies were conducted in uterine arteries (UtA) isolated from pregnant mice exposed to hypoxia or normoxia from gestational day 14.5 to 18.5. Exposure to troglitazone, a high-affinity PPARγ agonist-induced vasorelaxation in UtA preconstricted with phenylephrine, with HA-UtA showing increased sensitivity. Troglitazone blunted ET-1-induced contraction of UtA in hypoxic and normoxic dams equivalently. Immunohistological analysis revealed enhanced staining for ET-1 receptors in the placental labyrinthine zone in hypoxic compared to normoxic dams. Our results suggest that pharmacologic PPAR-γ activation, via its vasoactive properties, may protect the fetal growth under hypoxic conditions by improving uteroplacental perfusion and thereby justify further investigation into PPARγ as a therapeutic target for IUGR in pregnancies complicated by hypoxia.
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Affiliation(s)
- Sydney L Lane
- Integrated Physiology Program, University of Colorado Graduate School, Aurora, CO, USA.,Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Alexandrea S Doyle
- Department of Biochemistry, Colorado Mesa University, Grand Junction, CO, USA
| | - Elise S Bales
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Julie A Houck
- Department of Biochemistry, Colorado Mesa University, Grand Junction, CO, USA
| | - Ramón A Lorca
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Lorna G Moore
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Colleen G Julian
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
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7
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Limberg JK, Casey DP, Trinity JD, Nicholson WT, Wray DW, Tschakovsky ME, Green DJ, Hellsten Y, Fadel PJ, Joyner MJ, Padilla J. Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology. Am J Physiol Heart Circ Physiol 2019; 318:H301-H325. [PMID: 31886718 DOI: 10.1152/ajpheart.00649.2019] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,François M. Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | | | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia, Australia
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | | | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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8
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Craig JC, Broxterman RM, La Salle DT, Cerbie J, Ratchford SM, Gifford JR, Bunsawat K, Nelson AD, Bledsoe AD, Morgan DE, Wray DW, Richardson RS, Trinity JD. The role of endothelin A receptors in peripheral vascular control at rest and during exercise in patients with hypertension. J Physiol 2019; 598:71-84. [PMID: 31705661 DOI: 10.1113/jp279077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/01/2019] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Exercise in patients with hypertension can be accompanied by an abnormal cardiovascular response that includes attenuated blood flow and an augmented pressor response. Endothelin-1, a very potent vasoconstrictor, is a key modulator of blood flow and pressure during in health and has been implicated as a potential cause of the dysfunction in hypertension. We assessed the role of endothelin-1, acting through endothelin A (ETA ) receptors, in modulating the central and peripheral cardiovascular responses to exercise in patients with hypertension via local antagonism of these receptors during exercise. ETA receptor antagonism markedly increased leg blood flow, vascular conductance, oxygen delivery, and oxygen consumption during exercise; interestingly, these changes occurred in the presence of reduced leg perfusion pressure, indicating that these augmentations were driven by changes in vascular resistance. These data indicate that ETA receptor antagonism could be a viable therapeutic approach to improve blood flow during exercise in hypertension. ABSTRACT Patients with hypertension can exhibit impaired muscle blood flow and exaggerated increases in blood pressure during exercise. While endothelin (ET)-1 plays a role in regulating blood flow and pressure during exercise in health, little is known about the role of ET-1 in the cardiovascular response to exercise in hypertension. Therefore, eight volunteers diagnosed with hypertension were studied during exercise with either saline or BQ-123 (ETA receptor antagonist) infusion following a 2-week withdrawal of anti-hypertensive medications. The common femoral artery and vein were catheterized for drug infusion, blood collection and blood pressure measurements, and leg blood flow was measured by Doppler ultrasound. Patients exercised at both absolute (0, 5, 10, 15 W) and relative (40, 60, 80% peak power) intensities. BQ-123 increased blood flow at rest (79 ± 87 ml/min; P = 0.03) and augmented the exercise-induced hyperaemia at most intensities (80% saline: Δ3818±1222 vs. BQ-123: Δ4812±1469 ml/min; P = 0.001). BQ-123 reduced leg MAP at rest (-8 ± 4 mmHg; P < 0.001) and lower intensities (0-10 W; P < 0.05). Systemic diastolic blood pressure was reduced (0 W, 40%; P < 0.05), but systemic MAP was defended by an increased cardiac output. The exercise pressor response (ΔMAP) did not differ between conditions (80% saline: 25 ± 10, BQ-123: 30 ± 7 mmHg; P = 0.17). Thus, ET-1, acting through the ETA receptors, contributes to the control of blood pressure at rest and lower intensity exercise in these patients. Furthermore, the finding that ET-1 constrains the blood flow response to exercise suggests that ETA receptor antagonism could be a therapeutic approach to improve blood flow during exercise in hypertension.
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Affiliation(s)
- Jesse C Craig
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Ryan M Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| | - D Taylor La Salle
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
| | - James Cerbie
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
| | - Stephen M Ratchford
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| | - Jayson R Gifford
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah, USA
| | - Kanokwan Bunsawat
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Ashley D Nelson
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah, USA
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah, USA
| | - David E Morgan
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah, USA
| | - D Walter Wray
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
| | - Joel D Trinity
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
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9
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Hureau TJ, Weavil JC, Thurston TS, Wan HY, Gifford JR, Jessop JE, Buys MJ, Richardson RS, Amann M. Pharmacological attenuation of group III/IV muscle afferents improves endurance performance when oxygen delivery to locomotor muscles is preserved. J Appl Physiol (1985) 2019; 127:1257-1266. [PMID: 31513446 DOI: 10.1152/japplphysiol.00490.2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We sought to investigate the role of group III/IV muscle afferents in limiting endurance exercise performance, independently of their role in optimizing locomotor muscle O2 delivery. While breathing 100% O2 to ensure a similar arterial O2 content ([Formula: see text]) in both trials, eight male cyclists performed 5-km time trials under control conditions (HCTRL) and with lumbar intrathecal fentanyl (HFENT) impairing neural feedback from the lower limbs. After each time trial, common femoral artery blood flow (FBF) was quantified (Doppler ultrasound) during constant-load cycling performed at the average power of the preceding time trial. The assessment of end-tidal gases, hemoglobin content and saturation, and FBF facilitated the calculation of leg O2 delivery. Locomotor muscle activation during cycling was estimated from vastus lateralis EMG. With electrical femoral nerve stimulation, peripheral and central fatigue were quantified by pre- to postexercise decreases in quadriceps twitch torque (ΔQtw) and voluntary activation (ΔVA), respectively. FBF (~16 mL·min-1·W-1; P = 0.6), [Formula: see text] (~24 mL O2/dL; P = 0.9), and leg O2 delivery (~0.38 mL O2·min-1·W-1; P = 0.9) were not different during HCTRL and HFENT. Mean power output and time to completion were significantly improved by 9% (~310 W vs. ~288 W) and 3% (~479 s vs. ~463 s), respectively, during HFENT compared with HCTRL. Quadriceps muscle activation was 9 ± 7% higher during HFENT compared with HCTRL (P < 0.05). ΔQtw was significantly greater in HFENT compared with HCTRL (54 ± 8% vs. 39 ± 9%), whereas ΔVA was not different (~5%; P = 0.3) in both trials. These findings reveal that group III/IV muscle afferent feedback limits whole body endurance exercise performance and peripheral fatigue by restricting neural activation of locomotor muscle.NEW & NOTEWORTHY Group III/IV muscle afferent feedback facilitates endurance performance by optimizing locomotor muscle O2 delivery but also limits performance by restricting neural drive to locomotor muscle. To isolate the performance-limiting effect of these sensory neurons, we pharmacologically attenuated their central projection during a cycling time trial while controlling for locomotor muscle O2 delivery. With no difference in leg O2 delivery, afferent blockade attenuated the centrally mediated restriction in motoneuronal output and improved cycling performance.
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Affiliation(s)
- Thomas J Hureau
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Department of Medicine and EA 3072: Mitochondria, Oxidative Stress and Muscular Protection Laboratory, University of Strasbourg, Strasbourg, France
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Hsuan-Yu Wan
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Jayson R Gifford
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Michael J Buys
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Markus Amann
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.,Department of Anesthesiology, University of Utah, Salt Lake City, Utah
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10
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Barrett-O'Keefe Z, Lee JF, Ives SJ, Trinity JD, Witman MAH, Rossman MJ, Groot HJ, Sorensen JR, Morgan DE, Nelson AD, Stehlik J, Richardson RS, Wray DW. α-Adrenergic receptor regulation of skeletal muscle blood flow during exercise in heart failure patients with reduced ejection fraction. Am J Physiol Regul Integr Comp Physiol 2019; 316:R512-R524. [PMID: 30789790 DOI: 10.1152/ajpregu.00345.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Patients suffering from heart failure with reduced ejection fraction (HFrEF) experience impaired limb blood flow during exercise, which may be due to a disease-related increase in α-adrenergic receptor vasoconstriction. Thus, in eight patients with HFrEF (63 ± 4 yr) and eight well-matched controls (63 ± 2 yr), we examined changes in leg blood flow (Doppler ultrasound) during intra-arterial infusion of phenylephrine (PE; an α1-adrenergic receptor agonist) and phentolamine (Phen; a nonspecific α-adrenergic receptor antagonist) at rest and during dynamic single-leg knee-extensor exercise (0, 5, and 10 W). At rest, the PE-induced reduction in blood flow was significantly attenuated in patients with HFrEF (-15 ± 7%) compared with controls (-36 ± 5%). During exercise, the controls exhibited a blunted reduction in blood flow induced by PE (-12 ± 4, -10 ± 4, and -9 ± 2% at 0, 5, and 10 W, respectively) compared with rest, while the PE-induced change in blood flow was unchanged compared with rest in the HFrEF group (-8 ± 5, -10 ± 3, and -14 ± 3%, respectively). Phen administration increased leg blood flow to a greater extent in the HFrEF group at rest (+178 ± 34% vs. +114 ± 28%, HFrEF vs. control) and during exercise (36 ± 6, 37 ± 7, and 39 ± 6% vs. 13 ± 3, 14 ± 1, and 8 ± 3% at 0, 5, and 10 W, respectively, in HFrEF vs. control). Together, these findings imply that a HFrEF-related increase in α-adrenergic vasoconstriction restrains exercising skeletal muscle blood flow, potentially contributing to diminished exercise capacity in this population.
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Affiliation(s)
| | - Joshua F Lee
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah
| | - Stephen J Ives
- Department of Exercise and Sport Science, University of Utah , Salt Lake City, Utah
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Melissa A H Witman
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Matthew J Rossman
- Department of Exercise and Sport Science, University of Utah , Salt Lake City, Utah
| | - H Jon Groot
- Department of Exercise and Sport Science, University of Utah , Salt Lake City, Utah
| | - Jacob R Sorensen
- Department of Exercise and Sport Science, University of Utah , Salt Lake City, Utah
| | - David E Morgan
- Department of Anesthesiology, University of Utah , Salt Lake City, Utah
| | - Ashley D Nelson
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Josef Stehlik
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
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11
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Rapoport RM, Merkus D. Endothelin-1 Regulation of Exercise-Induced Changes in Flow: Dynamic Regulation of Vascular Tone. Front Pharmacol 2017; 8:517. [PMID: 29114220 PMCID: PMC5660699 DOI: 10.3389/fphar.2017.00517] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/24/2017] [Indexed: 12/12/2022] Open
Abstract
Although endothelin (ET)-1 is a highly potent vasoconstrictor with considerable efficacy in numerous vascular beds, the role of endogenous ET-1 in the regulation of vascular tone remains unclear. The perspective that ET-1 plays little role in the on-going regulation of vascular tone at least under physiologic conditions is supported by findings that potential ET-1 constriction is minimized by the release of the vasodilator and ET-1 synthesis inhibitor, nitric oxide (NO). Indeed, ET-1 release and constriction is self-limited by ET-1-induced, endothelial ETB receptor-mediated release of NO. Moreover, even if the balance between ET-1 and NO were reversed as the result of lowered NO activity, as occurs in a number of pathophysiologies associated with endothelial dysfunction, the well-known resistance of ET-1 constriction to reversal (as determined with exogenous ET-1) precludes ET-1 in the dynamic, i.e., moment-to-moment, regulation of vascular tone. On the other hand, and as presently reviewed, findings of ET-1-dependent modulation of organ blood flow with exercise under physiologic conditions demonstrate the dynamic regulation of vascular tone by ET-1. We speculate that this regulation is mediated at least in part through changes in ET-1 synthesis/release caused by pulsatile flow-induced shear stress and NO.
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Affiliation(s)
- Robert M Rapoport
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Daphne Merkus
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Cardiovascular Research School COEUR, Erasmus University Medical School Rotterdam, Rotterdam, Netherlands
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12
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Schroeder T, Piantadosi CA, Natoli MJ, Autmizguine J, Cohen-Wolkowieczs M, Hamilton KL, Bell C, Klawitter J, Christians U, Irwin DC, Noveck RJ. Safety and Ergogenic Properties of Combined Aminophylline and Ambrisentan in Hypoxia. Clin Pharmacol Ther 2017; 103:888-898. [PMID: 28857147 PMCID: PMC5947522 DOI: 10.1002/cpt.860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 01/24/2023]
Abstract
We hypothesized that concomitant pharmacological inhibition of the endothelin and adenosine pathway is safe and improves exercise performance in hypoxic humans, via a mechanism that does not involve augmentation of blood oxygenation. To test this hypothesis, we established safety and drug interactions for aminophylline (500 mg) plus ambrisentan (5 mg) in normoxic volunteers. Subsequently, a placebo-controlled study was employed to test the combination in healthy resting and exercising volunteers at simulated altitude (4,267 m). No serious adverse events occurred. Drug interaction was minimal or absent. Aminophylline alleviated hypoxia-induced headaches. Aminophylline, ambrisentan, and their combination all significantly (P < 0.05 vs. placebo) improved submaximal hypoxic exercise performance (19.5, 20.6, and 19.1% >placebo). Single-dose ambrisentan increased blood oxygenation in resting, hypoxic subjects. We conclude that combined aminophylline and ambrisentan offer promise to safely increase exercise capacity in hypoxemic humans without relying on increasing blood oxygen availability.
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Affiliation(s)
| | - Claude A Piantadosi
- Hyperbaric Center, Duke University Medical Center, Durham, North Carolina, USA
| | - Michael J Natoli
- Hyperbaric Center, Duke University Medical Center, Durham, North Carolina, USA
| | - Julie Autmizguine
- Department of Pharmacology, University of Montreal, Montreal, Quebec, Canada
| | - Michael Cohen-Wolkowieczs
- Duke Early Phase Clinical Research Unit, Duke Clinical Research Institute, Durham, North Carolina, USA
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado, USA
| | - Christopher Bell
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado, USA
| | - Jelena Klawitter
- iC42 Integrated Solutions in Clinical Research and Development, University of Colorado, Bioscience East, Aurora, Colorado, USA
| | - Uwe Christians
- iC42 Integrated Solutions in Clinical Research and Development, University of Colorado, Bioscience East, Aurora, Colorado, USA
| | - David C Irwin
- Department of Medicine, University of Colorado Denver Anschutz Campus, Aurora, Colorado, USA
| | - Robert J Noveck
- Hyperbaric Center, Duke University Medical Center, Durham, North Carolina, USA
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13
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Trinity JD, Layec G, Hart CR, Richardson RS. Sex-specific impact of aging on the blood pressure response to exercise. Am J Physiol Heart Circ Physiol 2017; 314:H95-H104. [PMID: 29030342 DOI: 10.1152/ajpheart.00505.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An exaggerated blood pressure (BP) response to exercise has been linked to cardiovascular disease, but little is known about the impact of age and sex on this response. Therefore, this study examined the hemodynamic and skeletal muscle metabolic response to dynamic plantar flexion exercise, at 40% of maximum plantar flexion work rate, in 40 physical activity-matched young (23 ± 1 yr, n = 20) and old (73 ± 2 yr, n = 20), equally distributed, male and female subjects. Central hemodynamics and BP (finometer), popliteal artery blood flow (Doppler ultrasound), and skeletal muscle metabolism (31P-magnetic resonance spectroscopy) were measured during 5 min of plantar flexion exercise. Popliteal artery blood flow and high-energy phosphate responses to exercise were not affected by age or sex, whereas aging, independent of sex, attenuated stroke volume and cardiac output responses. Systolic BP and mean arterial pressure responses were exaggerated in old women (Δ42 ± 4 and Δ28 ± 3 mmHg, respectively), with all other groups exhibiting similar increases in systolic BP (old men: Δ27 ± 8 mmHg, young men: Δ27 ± 3 mmHg, and young women: Δ22 ± 3 mmHg) and mean arterial pressure (old men: Δ15 ± 4 mmHg, young men: Δ19 ± 2 mmHg, and young women: Δ17 ± 2 mmHg). Interestingly, the exercise-induced change in systemic vascular resistance in old women (∆0.8 ± 1.0 mmHg·l-1·min-1) was augmented compared with young women and young and old men (∆-2.8 ± 0.5, ∆-1.6 ± 0.6, and ∆-3.18 ± 1.4 mmHg·l-1·min-1, respectively, P < 0.05). Thus, in combination, advancing age and female sex results in an exaggerated BP response to exercise, likely the result of a failure to reduce systemic vascular resistance. NEW & NOTEWORTHY An exaggerated blood pressure response to exercise has been linked to cardiovascular disease; however, little is known about how age and sex impact this response in healthy individuals. During dynamic exercise, older women exhibited an exaggerated blood pressure response driven by an inability to lower systemic vascular resistance.
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Affiliation(s)
- Joel D Trinity
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Gwenael Layec
- Department of Internal Medicine, Division of Geriatrics, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Corey R Hart
- Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
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14
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Strand TE, Khiabani HZ, Boico A, Radiloff D, Zhao Y, Hamilton KL, Christians U, Klawitter J, Noveck RJ, Piantadosi CA, Bell C, Irwin D, Schroeder T. The novel combination of theophylline and bambuterol as a potential treatment of hypoxemia in humans. Can J Physiol Pharmacol 2017; 95:1009-1018. [PMID: 28467859 DOI: 10.1139/cjpp-2016-0635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Hypoxemia can be life-threatening, both acutely and chronically. Because hypoxemia causes vascular dysregulation that further restricts oxygen availability to tissue, it can be pharmacologically addressed. We hypothesized that theophylline can be safely combined with the β2-adrenergic vasodilator bambuterol to improve oxygen availability in hypoxemic patients. Ergogenicity and hemodynamic effects of bambuterol and theophylline were measured in rats under hypobaric and normobaric hypoxia (12% O2). Feasibility in humans was assessed using randomized, double-blind testing of the influence of combined slow-release theophylline (300 mg) and bambuterol (20 mg) on adverse events (AEs), plasma K+, pulse, blood pressure, and drug interaction. Both drugs and their combination significantly improved hypoxic endurance in rats. In humans, common AEs were low K+ (<3.5 mmol/L; bambuterol: 12, theophylline: 4, combination: 13 episodes) and tremors (10, 0, 14 episodes). No exacerbation or serious AE occurred when drugs were combined. A drop in plasma K+ coincided with peak bambuterol plasma concentrations. Bambuterol increased heart rate by approximately 13 bpm. Drug interaction was present but small. We report promise, feasibility, and relative safety of combined theophylline and bambuterol as a treatment of hypoxemia in humans. Cardiac safety and blood K+ will be important safety endpoints when testing these drugs in hypoxemic subjects.
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Affiliation(s)
- Trond-Eirik Strand
- a Norwegian Armed Forces Medical Services, Institute of Aviation Medicine, 0313 Oslo, Norway
| | - Hasse Z Khiabani
- b Department of Pharmacology, Oslo University Hospital, Rikshospitalet, 0372 Oslo, Norway
| | - Alina Boico
- c Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Yulin Zhao
- c Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Karyn L Hamilton
- e Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA
| | - Uwe Christians
- f iC42 Integrated Solutions in Clinical Research and Development, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jelena Klawitter
- f iC42 Integrated Solutions in Clinical Research and Development, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Robert J Noveck
- g Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Christopher Bell
- e Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA
| | - David Irwin
- i Department of Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Thies Schroeder
- i Department of Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA.,j Department of Biochemistry and Pharmacology, University of Mainz, 55128 Mainz, Germany
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15
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Nishiyama SK, Zhao J, Wray DW, Richardson RS. Vascular function and endothelin-1: tipping the balance between vasodilation and vasoconstriction. J Appl Physiol (1985) 2016; 122:354-360. [PMID: 27909229 DOI: 10.1152/japplphysiol.00772.2016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/01/2016] [Accepted: 11/23/2016] [Indexed: 01/22/2023] Open
Abstract
Endothelin-1 (ET-1), a potent vasoconstrictor secreted by vascular endothelial cells, has been implicated in the pathophysiology of numerous cardiovascular diseases, yet the direct impact of ET-1 on vascular function remains unclear. Therefore, in seven young (23 ± 1 yr) healthy subjects, we investigated the effect of an intra-arterial infusion of ET-1 on reactive hyperemia (RH) and flow-mediated dilation (FMD) in the popliteal artery following 5 min of suprasystolic cuff occlusion. ET-1 infusion significantly attenuated basal leg blood flow (control: 62 ± 4 ml/min, ET-1: 47 ± 9 ml/min), RH [area-under-curve (AUC); control: 162 ± 15 ml, ET-1: 104 ± 16 ml], and peak RH (control: 572 ± 51 ml/min, ET-1: 412 ± 32 ml/min) (P < 0.05). Administration of ET-1 also reduced FMD (control: 2.4 ± 0.3%, ET-1: 0.5 ± 0.5%) and FMD normalized for shear rate (control: 10.5 × 10-4 ± 2.0 × 10-4%/s-1, ET-1: 0.9 × 10-4 ± 2.8 ×10-4%/s-1). These findings reveal that elevated levels of ET-1 have a significant impact on vascular function, indicating that studies employing RH and FMD as markers of microvascular function and nitric oxide bioavailability, respectively, should exercise caution, as ET-1 can impact these assessments by tipping the balance between vasodilation and vasoconstriction, in favor of the latter.NEW & NOTEWORTHY Endothelin-1 (ET-1) is recognized as the body's most potent endogenous vasoconstrictor, but the impact of this peptide on vascular function is not well understood. The present study revealed that the intra-arterial administration of ET-1 impaired both microvascular and conduit vessel function of the leg in young, healthy, humans. Studies employing vascular testing in patient cohorts that experience a disease-related increase in ET-1 should thus exercise caution, as ET-1 clearly impairs vascular function.
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Affiliation(s)
| | - Jia Zhao
- Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah
| | - D Walter Wray
- Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah; and.,Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Russell S Richardson
- Department of Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; .,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah; and.,Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Salt Lake City, Utah
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16
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Lee JF, Barrett-O'Keefe Z, Nelson AD, Garten RS, Ryan JJ, Nativi-Nicolau JN, Richardson RS, Wray DW. Impaired skeletal muscle vasodilation during exercise in heart failure with preserved ejection fraction. Int J Cardiol 2016; 211:14-21. [PMID: 26970959 DOI: 10.1016/j.ijcard.2016.02.139] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 02/28/2016] [Indexed: 01/25/2023]
Abstract
BACKGROUND Exercise intolerance is a hallmark symptom of heart failure patients with preserved ejection fraction (HFpEF), which may be related to an impaired ability to appropriately increase blood flow to the exercising muscle. METHODS We evaluated leg blood flow (LBF, ultrasound Doppler), heart rate (HR), stroke volume (SV), cardiac output (CO), and mean arterial blood pressure (MAP, photoplethysmography) during dynamic, single leg knee-extensor (KE) exercise in HFpEF patients (n=21; 68 ± 2 yrs) and healthy controls (n=20; 71 ± 2 yrs). RESULTS HFpEF patients exhibited a marked attrition during KE exercise, with only 60% able to complete the exercise protocol. In participants who completed all exercise intensities (0-5-10-15 W; HFpEF, n=13; Controls, n=16), LBF was not different at 0 W and 5 W, but was 15-25% lower in HFpEF compared to controls at 10 W and 15 W (P<0.001). Likewise, leg vascular conductance (LVC), an index of vasodilation, was not different at 0 W and 5 W, but was 15-20% lower in HFpEF compared to controls at 10 W and 15 W (P<0.05). In contrast to these peripheral deficits, exercise-induced changes in central variables (HR, SV, CO), as well as MAP, were similar between groups. CONCLUSIONS These data reveal a marked reduction in LBF and LVC in HFpEF patients during exercise that cannot be attributed to a disease-related alteration in central hemodynamics, suggesting that impaired vasodilation in the exercising skeletal muscle vasculature may play a key role in the exercise intolerance associated with this patient population.
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Affiliation(s)
- Joshua F Lee
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States; Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, UT, United States
| | - Zachary Barrett-O'Keefe
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, UT, United States; Department of Exercise & Sport Science, University of Utah, Salt Lake City, UT, United States
| | - Ashley D Nelson
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Ryan S Garten
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States; Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, UT, United States
| | - John J Ryan
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Jose N Nativi-Nicolau
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Russell S Richardson
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States; Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, UT, United States; Department of Exercise & Sport Science, University of Utah, Salt Lake City, UT, United States
| | - D Walter Wray
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States; Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, UT, United States; Department of Exercise & Sport Science, University of Utah, Salt Lake City, UT, United States.
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17
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Gifford JR, Garten RS, Nelson AD, Trinity JD, Layec G, Witman MAH, Weavil JC, Mangum T, Hart C, Etheredge C, Jessop J, Bledsoe A, Morgan DE, Wray DW, Rossman MJ, Richardson RS. Symmorphosis and skeletal muscle V̇O2 max : in vivo and in vitro measures reveal differing constraints in the exercise-trained and untrained human. J Physiol 2016; 594:1741-51. [PMID: 26614395 DOI: 10.1113/jp271229] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/10/2015] [Indexed: 01/15/2023] Open
Abstract
The concept of symmorphosis postulates a matching of structural capacity to functional demand within a defined physiological system, regardless of endurance exercise training status. Whether this concept applies to oxygen (O2 ) supply and demand during maximal skeletal muscle O2 consumption (V̇O2 max ) in humans is unclear. Therefore, in vitro skeletal muscle mitochondrial V̇O2 max (Mito V̇O2 max , mitochondrial respiration of fibres biopsied from vastus lateralis) was compared with in vivo skeletal muscle V̇O2 max during single leg knee extensor exercise (KE V̇O2 max , direct Fick by femoral arterial and venous blood samples and Doppler ultrasound blood flow measurements) and whole-body V̇O2 max during cycling (Body V̇O2 max , indirect calorimetry) in 10 endurance exercise-trained and 10 untrained young males. In untrained subjects, during KE exercise, maximal O2 supply (KE Q̇O2max ) exceeded (462 ± 37 ml kg(-1) min(-1) , P < 0.05) and KE V̇O2 max matched (340 ± 22 ml kg(-1) min(-1) , P > 0.05) Mito V̇O2 max (364 ± 16 ml kg(-1) min(-1) ). Conversely, in trained subjects, both KE Q̇O2max (557 ± 35 ml kg(-1) min(-1) ) and KE V̇O2 max (458 ± 24 ml kg(-1) min(-1) ) fell far short of Mito V̇O2 max (743 ± 35 ml kg(-1) min(-1) , P < 0.05). Although Mito V̇O2 max was related to KE V̇O2 max (r = 0.69, P < 0.05) and Body V̇O2 max (r = 0.91, P < 0.05) in untrained subjects, these variables were entirely unrelated in trained subjects. Therefore, in untrained subjects, V̇O2 max is limited by mitochondrial O2 demand, with evidence of adequate O2 supply, whereas, in trained subjects, an exercise training-induced mitochondrial reserve results in skeletal muscle V̇O2 max being markedly limited by O2 supply. Taken together, these in vivo and in vitro measures reveal clearly differing limitations and excesses at V̇O2 max in untrained and trained humans and challenge the concept of symmorphosis as it applies to O2 supply and demand in humans.
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Affiliation(s)
- Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Ryan S Garten
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Ashley D Nelson
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Gwenael Layec
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Melissa A H Witman
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Tyler Mangum
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Corey Hart
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Cory Etheredge
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Jake Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Amber Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - David E Morgan
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Matthew J Rossman
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, USA.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
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18
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Abstract
Aerobic exercise training leads to cardiovascular changes that markedly increase aerobic power and lead to improved endurance performance. The functionally most important adaptation is the improvement in maximal cardiac output which is the result of an enlargement in cardiac dimension, improved contractility, and an increase in blood volume, allowing for greater filling of the ventricles and a consequent larger stroke volume. In parallel with the greater maximal cardiac output, the perfusion capacity of the muscle is increased, permitting for greater oxygen delivery. To accommodate the higher aerobic demands and perfusion levels, arteries, arterioles, and capillaries adapt in structure and number. The diameters of the larger conduit and resistance arteries are increased minimizing resistance to flow as the cardiac output is distributed in the body and the wall thickness of the conduit and resistance arteries is reduced, a factor contributing to increased arterial compliance. Endurance training may also induce alterations in the vasodilator capacity, although such adaptations are more pronounced in individuals with reduced vascular function. The microvascular net increases in size within the muscle allowing for an improved capacity for oxygen extraction by the muscle through a greater area for diffusion, a shorter diffusion distance, and a longer mean transit time for the erythrocyte to pass through the smallest blood vessels. The present article addresses the effect of endurance training on systemic and peripheral cardiovascular adaptations with a focus on humans, but also covers animal data.
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Affiliation(s)
- 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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19
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Nyberg M, Gliemann L, Hellsten Y. Vascular function in health, hypertension, and diabetes: effect of physical activity on skeletal muscle microcirculation. Scand J Med Sci Sports 2015; 25 Suppl 4:60-73. [DOI: 10.1111/sms.12591] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2015] [Indexed: 12/31/2022]
Affiliation(s)
- M. Nyberg
- Department of Nutrition, Exercise and Sports; University of Copenhagen; Copenhagen Denmark
| | - L. Gliemann
- Department of Nutrition, Exercise and Sports; University of Copenhagen; Copenhagen Denmark
| | - Y. Hellsten
- Department of Nutrition, Exercise and Sports; University of Copenhagen; Copenhagen Denmark
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20
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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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21
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Kaur J, Machado TM, Alvarez A, Krishnan AC, Hanna HW, Altamimi YH, Senador D, Spranger MD, O'Leary DS. Muscle metaboreflex activation during dynamic exercise vasoconstricts ischemic active skeletal muscle. Am J Physiol Heart Circ Physiol 2015; 309:H2145-51. [PMID: 26475591 DOI: 10.1152/ajpheart.00679.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/12/2015] [Indexed: 11/22/2022]
Abstract
Metabolite accumulation due to ischemia of active skeletal muscle stimulates group III/IV chemosensitive afferents eliciting reflex increases in arterial blood pressure and sympathetic activity, termed the muscle metaboreflex. We and others have previously demonstrated sympathetically mediated vasoconstriction of coronary, renal, and forelimb vasculatures with muscle metaboreflex activation (MMA). Whether MMA elicits vasoconstriction of the ischemic muscle from which it originates is unknown. We hypothesized that the vasodilation in active skeletal muscle with imposed ischemia becomes progressively restrained by the increasing sympathetic vasoconstriction during MMA. We activated the metaboreflex during mild dynamic exercise in chronically instrumented canines via graded reductions in hindlimb blood flow (HLBF) before and after α1-adrenergic blockade [prazosin (50 μg/kg)], β-adrenergic blockade [propranolol (2 mg/kg)], and α1 + β-blockade. Hindlimb resistance was calculated as femoral arterial pressure/HLBF. During mild exercise, HLBF must be reduced below a threshold level before the reflex is activated. With initial reductions in HLBF, vasodilation occurred with the imposed ischemia. Once the muscle metaboreflex was elicited, hindlimb resistance increased. This increase in hindlimb resistance was abolished by α1-adrenergic blockade and exacerbated after β-adrenergic blockade. We conclude that metaboreflex activation during submaximal dynamic exercise causes sympathetically mediated α-adrenergic vasoconstriction in ischemic skeletal muscle. This limits the ability of the reflex to improve blood flow to the muscle.
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Affiliation(s)
- Jasdeep Kaur
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Tiago M Machado
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Alberto Alvarez
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Abhinav C Krishnan
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Hanna W Hanna
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Yasir H Altamimi
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Danielle Senador
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Marty D Spranger
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Donal S O'Leary
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
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22
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Ichinose M, Ichinose-Kuwahara T, Kondo N, Nishiyasu T. Increasing blood flow to exercising muscle attenuates systemic cardiovascular responses during dynamic exercise in humans. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1234-42. [PMID: 26377556 DOI: 10.1152/ajpregu.00063.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 09/09/2015] [Indexed: 11/22/2022]
Abstract
Reducing blood flow to working muscles during dynamic exercise causes metabolites to accumulate within the active muscles and evokes systemic pressor responses. Whether a similar cardiovascular response is elicited with normal blood flow to exercising muscles during dynamic exercise remains unknown, however. To address that issue, we tested whether cardiovascular responses are affected by increases in blood flow to active muscles. Thirteen healthy subjects performed dynamic plantarflexion exercise for 12 min at 20%, 40%, and 60% of peak workload (EX20, EX40, and EX60) with their lower thigh enclosed in a negative pressure box. Under control conditions, the box pressure was the same as the ambient air pressure. Under negative pressure conditions, beginning 3 min after the start of the exercise, the box pressure was decreased by 20, 45, and then 70 mmHg in stepwise fashion with 3-min step durations. During EX20, the negative pressure had no effect on blood flow or the cardiovascular responses measured. However, application of negative pressure increased blood flow to the exercising leg during EX40 and EX60. This increase in blood flow had no significant effect on systemic cardiovascular responses during EX40, but it markedly attenuated the pressor responses otherwise seen during EX60. These results demonstrate that during mild exercise, normal blood flow to exercising muscle is not a factor eliciting cardiovascular responses, whereas it elicits an important pressor effect during moderate exercise. This suggests blood flow to exercising muscle is a major determinant of cardiovascular responses during dynamic exercise at higher than moderate intensity.
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Affiliation(s)
- Masashi Ichinose
- Human Integrative Physiology Laboratory, School of Business Administration, Meiji University, Tokyo, Japan;
| | - Tomoko Ichinose-Kuwahara
- Human Integrative Physiology Laboratory, School of Business Administration, Meiji University, Tokyo, Japan; Laboratory for Human Performance Research, Osaka International University, Osaka, Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Faculty of Human Development, Kobe University, Kobe, Japan; and
| | - Takeshi Nishiyasu
- Institute of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
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23
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Cooke AB, Toli E, Gomez YH, Mutter AF, Eisenberg MJ, Mantzoros CS, Daskalopoulou SS. From rest to stressed: endothelin-1 levels in young healthy smokers and non-smokers. Metabolism 2015; 64:1103-11. [PMID: 26141182 DOI: 10.1016/j.metabol.2015.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Endothelin-1 (ET-1) is a potent vasoconstrictor produced by vascular endothelial cells, and a known marker of endothelial dysfunction. However, the acute and chronic effects of smoking and nicotine gum on the ET-1 response to acute physical stress in young healthy smokers have not been investigated. METHODS Healthy smokers (n=35) and non-smokers (n=35) underwent an exercise test to exhaustion (maximal oxygen consumption) on a treadmill. Smokers were assessed a) after 12h smoking abstinence (termed chronic smoking), b) immediately after smoking one cigarette (termed acute smoking), and c) immediately after chewing nicotine gum. Blood was drawn immediately pre-exercise, and 3 minutes post-exercise. During exercise, cardiorespiratory parameters were obtained breath-by-breath using an automated metabolic cart. Plasma ET-1 levels were quantified using enzyme-linked immunosorbent-assay. The above protocol was designed to incorporate exercise as a vascular stressor to reveal changes that would not be detected at rest. RESULTS Mean age was 28.6±7.2 years and body mass index (BMI) was 23.6±3.2 kg/m(2). Post-exercise ET-1 levels were significantly lower than pre-exercise levels in non-smokers (P<0.001) and smokers under all three conditions (P=0.005, P<0.001, P=0.001, respectively). There were no differences in post-exercise ET-1 levels between non-smokers and smokers under all three conditions, however the absolute and relative decrease in ET-1 levels was significantly smaller in chronic smokers compared with non-smokers (P=0.007 and P=0.004). Chronic smokers had a significantly lower exercise-induced change in tidal volume (P=0.050), fraction of expired CO2 (P=0.021), oxygen consumption (P=0.005), carbon dioxide elimination (P=0.004) and peak expiratory flow (P=0.003) compared with non-smokers. Furthermore, the decrease in ET-1 observed in non-smokers in response to exercise was significantly associated with exercise induced-changes in inspiratory time, time for a tidal volume cycle, respiratory frequency, inspired minute ventilation and peak inspiratory flow. CONCLUSIONS An acute decrease of circulating ET-1 in response to acute maximal exercise in young healthy individuals was noted. Chronic smokers had a significantly diminished decrease in ET-1 compared with non-smokers, however there were no significant differences in the ET-1 response between smokers under the three smoking conditions. Smokers were not able to achieve the same exercise-induced changes in cardiorespiratory parameters as non-smokers. By incorporating exercise as a vascular stressor in our study, we have taken a novel approach to provide evidence of an altered ET-1 and cardiorespiratory response that would not otherwise be observed at rest in young active healthy smokers.
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Affiliation(s)
- Alexandra B Cooke
- Division of Experimental Medicine, Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, H3A 1A3, Canada
| | - Eirini Toli
- Division of Internal Medicine, Department of Medicine, Faculty of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec, H3G 1A4, Canada
| | - Yessica-Haydee Gomez
- Division of Internal Medicine, Department of Medicine, Faculty of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec, H3G 1A4, Canada
| | - Andrew F Mutter
- Division of Experimental Medicine, Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, H3A 1A3, Canada
| | - Mark J Eisenberg
- Division of Cardiology, Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, H3G 1Y6, Canada; Division of Clinical Epidemiology, Department of Medicine, Faculty of Medicine, Jewish General Hospital, Montreal, Quebec, H3T 1E2, Canada
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes and Metabolism, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA; VA Section of Endocrinology, VA Boston Healthcare System, Harvard Medical School, Boston, MA, USA
| | - Stella S Daskalopoulou
- Division of Experimental Medicine, Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, H3A 1A3, Canada; Division of Internal Medicine, Department of Medicine, Faculty of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec, H3G 1A4, Canada.
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24
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Rossman MJ, Trinity JD, Garten RS, Ives SJ, Conklin JD, Barrett-O'Keefe Z, Witman MAH, Bledsoe AD, Morgan DE, Runnels S, Reese VR, Zhao J, Amann M, Wray DW, Richardson RS. Oral antioxidants improve leg blood flow during exercise in patients with chronic obstructive pulmonary disease. Am J Physiol Heart Circ Physiol 2015; 309:H977-85. [PMID: 26188020 DOI: 10.1152/ajpheart.00184.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 07/10/2015] [Indexed: 11/22/2022]
Abstract
The consequence of elevated oxidative stress on exercising skeletal muscle blood flow as well as the transport and utilization of O2 in patients with chronic obstructive pulmonary disease (COPD) is not well understood. The present study examined the impact of an oral antioxidant cocktail (AOC) on leg blood flow (LBF) and O2 consumption during dynamic exercise in 16 patients with COPD and 16 healthy subjects. Subjects performed submaximal (3, 6, and 9 W) single-leg knee extensor exercise while LBF (Doppler ultrasound), mean arterial blood pressure, leg vascular conductance, arterial O2 saturation, leg arterial-venous O2 difference, and leg O2 consumption (direct Fick) were evaluated under control conditions and after AOC administration. AOC administration increased LBF (3 W: 1,604 ± 100 vs. 1,798 ± 128 ml/min, 6 W: 1,832 ± 109 vs. 1,992 ± 120 ml/min, and 9W: 2,035 ± 114 vs. 2,187 ± 136 ml/min, P < 0.05, control vs. AOC, respectively), leg vascular conductance, and leg O2 consumption (3 W: 173 ± 12 vs. 210 ± 15 ml O2/min, 6 W: 217 ± 14 vs. 237 ± 15 ml O2/min, and 9 W: 244 ± 16 vs 260 ± 18 ml O2/min, P < 0.05, control vs. AOC, respectively) during exercise in COPD, whereas no effect was observed in healthy subjects. In addition, the AOC afforded a small, but significant, improvement in arterial O2 saturation only in patients with COPD. Thus, these data demonstrate a novel beneficial role of AOC administration on exercising LBF, O2 consumption, and arterial O2 saturation in patients with COPD, implicating oxidative stress as a potential therapeutic target for impaired exercise capacity in this population.
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Affiliation(s)
- Matthew J Rossman
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Ryan S Garten
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Stephen J Ives
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, New York
| | - Jamie D Conklin
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Division of Respiratory, Critical Care and Occupational Pulmonary Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, Utah; and
| | - Zachary Barrett-O'Keefe
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Melissa A H Witman
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - David E Morgan
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Sean Runnels
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Van R Reese
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Jia Zhao
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Markus Amann
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah;
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25
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Holwerda SW, Restaino RM, Fadel PJ. Adrenergic and non-adrenergic control of active skeletal muscle blood flow: implications for blood pressure regulation during exercise. Auton Neurosci 2014; 188:24-31. [PMID: 25467222 DOI: 10.1016/j.autneu.2014.10.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/18/2014] [Accepted: 10/13/2014] [Indexed: 12/13/2022]
Abstract
Blood flow to active skeletal muscle increases markedly during dynamic exercise. However, despite the massive capacity of skeletal muscle vasculature to dilate, arterial blood pressure is well maintained. Sympathetic nerve activity is elevated with increased intensity of dynamic exercise, and is essential for redistribution of cardiac output to active skeletal muscle and maintenance of arterial blood pressure. In addition, aside from the sympathetic nervous system, evidence from human studies is now emerging that supports roles for non-adrenergic vasoconstrictor pathways that become active during exercise and contribute to vasoconstriction in active skeletal muscle. Neuropeptide Y and adenosine triphosphate are neurotransmitters that are co-released with norepinephrine from sympathetic nerve terminals capable of producing vasoconstriction. Likewise, plasma concentrations of arginine vasopressin, angiotensin II (Ang II) and endothelin-1 (ET-1) increase during dynamic exercise, particularly at higher intensities. Ang II and ET-1 have both been shown to be important vasoconstrictor pathways for restraint of blood flow in active skeletal muscle and the maintenance of arterial blood pressure during exercise. Indeed, although both adrenergic and non-adrenergic vasoconstriction can be attenuated in exercising muscle with greater intensity of exercise, with the higher volume of blood flow, the active skeletal muscle vasculature remains capable of contributing importantly to the maintenance of blood pressure. In this brief review we provide an update on skeletal muscle blood flow regulation during exercise with an emphasis on adrenergic and non-adrenergic vasoconstrictor pathways and their potential capacity to offset vasodilation and aid in the regulation of blood pressure.
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Affiliation(s)
- Seth W Holwerda
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Robert M Restaino
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Paul J Fadel
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States; Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States.
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Barrett-O'Keefe Z, Lee JF, Berbert A, Witman MAH, Nativi-Nicolau J, Stehlik J, Richardson RS, Wray DW. Hemodynamic responses to small muscle mass exercise in heart failure patients with reduced ejection fraction. Am J Physiol Heart Circ Physiol 2014; 307:H1512-20. [PMID: 25260608 DOI: 10.1152/ajpheart.00527.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To better understand the mechanisms responsible for exercise intolerance in heart failure with reduced ejection fraction (HFrEF), the present study sought to evaluate the hemodynamic responses to small muscle mass exercise in this cohort. In 25 HFrEF patients (64 ± 2 yr) and 17 healthy, age-matched control subjects (64 ± 2 yr), mean arterial pressure (MAP), cardiac output (CO), and limb blood flow were examined during graded static-intermittent handgrip (HG) and dynamic single-leg knee-extensor (KE) exercise. During HG exercise, MAP increased similarly between groups. CO increased significantly (+1.3 ± 0.3 l/min) in the control group, but it remained unchanged across workloads in HFrEF patients. At 15% maximum voluntary contraction (MVC), forearm blood flow was similar between groups, while HFrEF patients exhibited an attenuated increase at the two highest intensities compared with controls, with the greatest difference at the highest workload (352 ± 22 vs. 492 ± 48 ml/min, HFrEF vs. control, 45% MVC). During KE exercise, MAP and CO increased similarly across work rates between groups. However, HFrEF patients exhibited a diminished leg hyperemic response across all work rates, with the most substantial decrement at the highest intensity (1,842 ± 64 vs. 2,675 ± 81 ml/min; HFrEF vs. control, 15 W). Together, these findings indicate a marked attenuation in exercising limb perfusion attributable to impairments in peripheral vasodilatory capacity during both arm and leg exercise in patients with HFrEF, which likely plays a role in limiting exercise capacity in this patient population.
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Affiliation(s)
- Zachary Barrett-O'Keefe
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Joshua F Lee
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah
| | - Amanda Berbert
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Melissa A H Witman
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Jose Nativi-Nicolau
- Department of Internal Medicine, Division of Cardiology, University of Utah, Salt Lake City, Utah; and
| | - Josef Stehlik
- Department of Internal Medicine, Division of Cardiology, University of Utah, Salt Lake City, Utah; and
| | - Russell S Richardson
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; University of Utah Center on Aging, Salt Lake City, Utah
| | - D Walter Wray
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; University of Utah Center on Aging, Salt Lake City, Utah
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27
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Barrett-O'Keefe Z, Ives SJ, Trinity JD, Morgan G, Rossman MJ, Donato AJ, Runnels S, Morgan DE, Gmelch BS, Bledsoe AD, Richardson RS, Wray DW. Endothelin-A-mediated vasoconstriction during exercise with advancing age. J Gerontol A Biol Sci Med Sci 2014; 70:554-65. [PMID: 24821105 DOI: 10.1093/gerona/glu065] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/31/2014] [Indexed: 11/14/2022] Open
Abstract
The endothelin-1 vasoconstrictor pathway contributes to age-related elevations in resting peripheral vascular tone primarily through activation of the endothelin subtype A (ET(A)) receptor. However, the regulatory influence of ET(A)-mediated vasoconstriction during exercise in the elderly is unknown. Thus, in 17 healthy volunteers (n = 8 young, 24±2 years; n = 9 old, 70±2 years), we examined leg blood flow, mean arterial pressure, leg arterial-venous oxygen (O2) difference, and leg O2 consumption (VO2) at rest and during knee-extensor exercise before and after intra-arterial administration of the ET(A) antagonist BQ-123. During exercise, BQ-123 administration increased leg blood flow to a greater degree in the old (+29±5 mL/min/W) compared with the young (+16±3 mL/min/W). The increase in leg blood flow with BQ-123 was accompanied by an increase in leg VO2 in both groups, suggesting a reduced efficiency following ET(A) receptor blockade. Together, these findings have identified an age-related increase in ET(A)-mediated vasoconstrictor activity that persists during exercise, suggesting an important role of this pathway in the regulation of exercising skeletal muscle blood flow and maintenance of arterial blood pressure in the elderly.
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Affiliation(s)
- Zachary Barrett-O'Keefe
- Department of Exercise and Sport Science, University of Utah, Salt Lake City. Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah
| | - Stephen J Ives
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah. Department of Internal Medicine, University of Utah, Salt Lake City
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah. Department of Internal Medicine, University of Utah, Salt Lake City
| | - Garrett Morgan
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah
| | - Matthew J Rossman
- Department of Exercise and Sport Science, University of Utah, Salt Lake City. Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah
| | - Anthony J Donato
- Department of Exercise and Sport Science, University of Utah, Salt Lake City. Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah. Department of Internal Medicine, University of Utah, Salt Lake City. University of Utah Center on Aging, Salt Lake City
| | - Sean Runnels
- Department of Anesthesiology, University of Utah, Salt Lake City
| | - David E Morgan
- Department of Anesthesiology, University of Utah, Salt Lake City
| | | | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City
| | - Russell S Richardson
- Department of Exercise and Sport Science, University of Utah, Salt Lake City. Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah. Department of Internal Medicine, University of Utah, Salt Lake City. University of Utah Center on Aging, Salt Lake City
| | - D Walter Wray
- Department of Exercise and Sport Science, University of Utah, Salt Lake City. Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah. Department of Internal Medicine, University of Utah, Salt Lake City. University of Utah Center on Aging, Salt Lake City.
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De Mey JGR, Vanhoutte PM. End o' the line revisited: moving on from nitric oxide to CGRP. Life Sci 2014; 118:120-8. [PMID: 24747136 DOI: 10.1016/j.lfs.2014.04.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/24/2022]
Abstract
When endothelin-1(ET-1) was discovered it was hailed as the prototypical endothelium-derived contracting factor (EDCF). However, over the years little evidence emerged convincingly demonstrating that the peptide actually contributes to moment-to-moment changes in vascular tone elicited by endothelial cells. This has been attributed to the profound inhibitory effect of nitric oxide (NO) on both the production (by the endothelium) and the action (on vascular smooth muscle) of ET-1. Hence, the peptide is likely to initiate acute changes in vascular diameter only under extreme conditions of endothelial dysfunction when the NO bioavailability is considerably reduced if not absent. The present essay discusses whether or not this concept should be revised, in particular in view of the potent inhibitory effect exerted by calcitonin gene related peptide (CGRP) released from sensorimotor nerves on vasoconstrictor responses to ET-1.
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Affiliation(s)
- Jo G R De Mey
- Institute of Molecular Medicine, University of South Denmark, Odense, Denmark; Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
| | - Paul M Vanhoutte
- Institute of Molecular Medicine, University of South Denmark, Odense, Denmark; Department of Pharmacology and Pharmacy and State Key Laboratory for Pharmaceutical Biotechnology, University of Hong Kong, Hong Kong, China.
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29
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Buck TM, Sieck DC, Halliwill JR. Thin-beam ultrasound overestimation of blood flow: how wide is your beam? J Appl Physiol (1985) 2014; 116:1096-104. [PMID: 24557801 DOI: 10.1152/japplphysiol.00027.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been predicted that the development of thin-beam ultrasound could lead to an overestimation of mean blood velocity by up to 33% as beam width approaches 0% of vessel diameter. If both beam and vessel widths are known, in theory, this overestimation may be correctable. Therefore, we updated a method for determining the beam width of a Doppler ultrasound system, tested the utility of this technique and the information it provides to reliably correct for the error in velocity measurements, and explored how error-corrected velocity estimates impact the interpretation of in vivo data. Using a string phantom, we found the average beam width of four different probes varied across probes from 2.93 ± 0.05 to 4.41 ± 0.06 mm (mean ± SD) and with depth of insonation. Using this information, we tested the validity of a calculated correction factor to minimize the thin-beam error in mean velocity observed in a flow phantom with known diameter. Use of a correction factor reduced the overestimation from 39 ± 11 to 7 ± 9% (P < 0.05). Lastly, in vivo we explored how knowledge of beam width improves understanding of physiological flow conditions. In vivo, use of a correction factor reduced the overestimation of mean velocity from 23 ± 11 to -4 ± 9% (P < 0.05). Thus this large source of error is real, has been largely ignored by the early adaptors of Doppler ultrasound for vascular physiology studies in humans, and is correctable by the described techniques.
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Affiliation(s)
- Tahisha M Buck
- Department of Human Physiology, University of Oregon, Eugene, Oregon
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Mitchell WK, Phillips BE, Williams JP, Rankin D, Smith K, Lund JN, Atherton PJ. Development of a new Sonovue™ contrast-enhanced ultrasound approach reveals temporal and age-related features of muscle microvascular responses to feeding. Physiol Rep 2013; 1:e00119. [PMID: 24303186 PMCID: PMC3841050 DOI: 10.1002/phy2.119] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 09/12/2013] [Accepted: 09/16/2013] [Indexed: 12/17/2022] Open
Abstract
Compromised limb blood flow in aging may contribute to the development of sarcopenia, frailty, and the metabolic syndrome. We developed a novel contrast-enhanced ultrasound technique using Sonovue™ to characterize muscle microvasculature responses to an oral feeding stimulus (15 g essential amino acids) in young (∼20 years) and older (∼70 years) men. Intensity-time replenishment curves were made via an ultrasound probe “fixed” over the quadriceps, with intermittent high mechanical index destruction of microbubbles within muscle vasculature. This permitted real-time measures of microvascular blood volume (MBV), microvascular flow velocity (MFV) and their product, microvascular blood flow (MBF). Leg blood flow (LBF) was measured by Doppler and insulin by enzyme-linked immunosorbent assay. Steady-state contrast concentrations needed for comparison between different physiological states were achieved <150 sec from commencing Sonovue™ infusion, and MFV and MBV measurements were completed <120 sec thereafter. Interindividual coefficients of variation in MBV and MFV were 35–40%, (N = 36). Younger men (N = 6) exhibited biphasic vascular responses to feeding with early increases in MBV (+36%, P < 0.008 45 min post feed) reflecting capillary recruitment, and late increases in MFV (+77%, P < 0.008) and MBF (+130%, P < 0.007 195 min post feed) reflecting more proximal vessel dilatation. Early MBV responses were synchronized with peak insulin but not increased LBF, while later changes in MFV and MBF occurred with insulin at post absorptive values but alongside increased LBF. All circulatory responses were absent in old men (N = 7). Thus, impaired postprandial circulation could impact age-related declines in muscle glucose disposal, protein anabolism, and muscle mass.
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Affiliation(s)
- William Kyle Mitchell
- Division of Clinical Metabolic and Molecular Physiology, School of Graduate Entry Medicine and Health, University of Nottingham Derby, U.K. ; Department of Surgery, Royal Derby Hospital Derby, U.K
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31
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Stanley WC, Keehan KH. Update on innovative initiatives for the American Journal of Physiology-Heart and Circulatory Physiology. Am J Physiol Heart Circ Physiol 2013; 304:H1045-9. [PMID: 23457015 DOI: 10.1152/ajpheart.00082.2013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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