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The impact of repeated, local heating-induced increases in blood flow on lower limb endothelial function in young, healthy females. Eur J Appl Physiol 2021; 121:3017-3030. [PMID: 34251539 DOI: 10.1007/s00421-021-04749-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 06/15/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE The purpose of the present study was to examine the effect of repeated, single leg heating on lower limb endothelial function. METHODS Macrovascular function was assessed with superficial femoral artery (SFA) reactive hyperemia flow-mediated dilation (RH-FMD) and sustained stimulus FMD (SS-FMD). Calf microvascular function was assessed as the peak and area under the curve of SFA reactive hyperemia (RH). Participants (n = 13 females, 23 ± 2 yrs) had one leg randomized to the single leg heating intervention (EXP; other leg: control (CON)). The EXP leg underwent 8 weeks of single leg heating via immersion in 42.5 ℃ water for five 35-min sessions/week. At weeks 0, 2, 4, 6, and 8, SFA RH-FMD, SS-FMD (shear stress increased via plantar flexion exercise), and SFA RH flow were measured. RESULTS None of the variables changed with repeated, single leg heating (interaction week*limb RH-FMD: p = 0.076; SS-FMD: p = 0.958; RH flow p = 0.955). Covariation for the shear stress stimulus did not alter the FMD results. CONCLUSION Eight weeks of single leg heating did not change SFA endothelial or calf microvascular function. These results are in contrast with previous findings that limb heating improves upper limb endothelial function.
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Carr J, Tremblay JC, Ives SJ, Lyall GK, Baldwin MM, Birch KM, Lee KD, Papadedes DW, King TJ, Gibbons TD, Thomas KN, Hanson BE, Bock JM, Casey DP, Ruediger SL, Bailey TG, Amin SB, Hansen AB, Lawley JS, Williams JS, Cheng JL, MacDonald MJ. Commentaries on Viewpoint: Differential impact of shear rate in the cerebral and systemic circulation: implications for endothelial function. J Appl Physiol (1985) 2021; 130:1155-1160. [PMID: 33877934 DOI: 10.1152/japplphysiol.00045.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Jay Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia–Okanagan Campus, School of Health and Exercise Sciences, Kelowna, British Columbia, Canada
| | - Joshua C. Tremblay
- Centre for Heart, Lung and Vascular Health, University of British Columbia–Okanagan Campus, School of Health and Exercise Sciences, Kelowna, British Columbia, Canada
| | - Stephen J. Ives
- Health and Human Physiological Sciences, Skidmore College, Saratoga Springs, New York
| | - Gemma K. Lyall
- School of Biomedical Sciences, Faculty of Biological Sciences and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Molly M. Baldwin
- School of Biomedical Sciences, Faculty of Biological Sciences and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Karen M. Birch
- School of Biomedical Sciences, Faculty of Biological Sciences and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Kaitlyn D. Lee
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | | | - Trevor J. King
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Travis D. Gibbons
- Department of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Kate N. Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Brady E. Hanson
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joshua M. Bock
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
| | - Darren P. Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Stefanie L. Ruediger
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre of Research on Exercise, Physical Activity and Health, The University of Queensland, Queensland, Australia
| | - Tom G. Bailey
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre of Research on Exercise, Physical Activity and Health, The University of Queensland, Queensland, Australia,School of Nursing, Midwifery and Social Work, The University of Queensland, Queensland, Australia
| | - Sachin B. Amin
- Institute for Sport Science, Division of Physiology, Innsbruck University, Innsbruck, Austria
| | - Alexander B. Hansen
- Institute for Sport Science, Division of Physiology, Innsbruck University, Innsbruck, Austria
| | - Justin S. Lawley
- Institute for Sport Science, Division of Physiology, Innsbruck University, Innsbruck, Austria
| | - Jennifer S. Williams
- Vascular Dynamics Lab, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Jem L. Cheng
- Vascular Dynamics Lab, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Maureen J. MacDonald
- Vascular Dynamics Lab, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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3
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Kaur J, Barbosa TC, Nandadeva D, Young BE, Stephens BY, Brothers RM, Fadel PJ. Attenuated Rapid-Onset Vasodilation to Forearm Muscle Contraction in Black Men. Med Sci Sports Exerc 2021; 53:590-596. [PMID: 32910095 PMCID: PMC7909956 DOI: 10.1249/mss.0000000000002511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE Non-Hispanic Black individuals have a blunted ability to vasodilate at rest compared with other racial groups. Limited studies have investigated blood flow responses to exercise in Black individuals. Recently, our laboratory demonstrated that Black men exhibit attenuated increases in forearm vascular conductance (FVC) during steady-state rhythmic handgrip. The mechanisms for this remain unknown. Herein, we used single muscle contractions, a modality that allows for assessment of rapid-onset vasodilation (ROV) independent of major elevations in shear stress, tissue metabolism, and systemic hemodynamics. METHODS Ten young, healthy Black and White men performed single forearm contractions at 20%, 40%, and 60% maximal voluntary contraction (MVC). In addition, cuff inflations were performed on the forearm to examine the contribution of mechanical compression to ROV. Forearm blood flow (FBF; duplex Doppler ultrasound), heart rate (ECG), and mean arterial pressure (Finometer) were continuously measured. FVC was calculated as FBF/mean arterial pressure. RESULTS Baseline FVC (White men vs Black men, 0.75 ± 0.11 vs 0.80 ± 0.09 mL·min-1·mm Hg-1; P = 0.73), FBF, and MVCs (White men vs Black men, 54 ± 2 vs 54 ± 2 kg; P = 0.95) were similar between the groups. After single contractions, both groups exhibited intensity-dependent FVC and FBF increases during ROV; however, these responses were attenuated in the Black group at all intensities (e.g., 60%MVC FVC: White men vs Black men, +371% ± 37% vs +220% ± 23% baseline; P = 0.001). FVC and FBF responses to cuff inflation alone were also attenuated in Black individuals (P < 0.001). CONCLUSIONS Collectively, these data indicate that Black men have an overall blunted ability to rapidly vasodilate compared with young White men.
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Affiliation(s)
- Jasdeep Kaur
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX
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4
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Cheung CP, Coates AM, Millar PJ, Burr JF. Habitual cannabis use is associated with altered cardiac mechanics and arterial stiffness, but not endothelial function in young healthy smokers. J Appl Physiol (1985) 2021; 130:660-670. [PMID: 33444123 DOI: 10.1152/japplphysiol.00840.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cigarette smoking is among the most detrimental behaviors to cardiovascular health, resulting in arterial stiffening, endothelial dysfunction, and structural/functional alterations to the myocardium. Similar to cigarettes, cannabis is commonly smoked, and next to alcohol, is the most commonly used recreational substance in the world. Despite this, little is known about the long-term cardiovascular effects of smoking cannabis. This study explored the associations of cardiovascular structure and function with cannabis use in ostensibly healthy young participants (n = 35). Using echocardiography, carotid-femoral pulse wave velocity (cfPWV), and brachial flow-mediated dilation (FMD), we performed a cross-sectional assessment of cardiovascular function in cannabis users (n = 18) and controls (n = 17). There were no differences in cardiac morphology or traditional resting measures of systolic or diastolic function between cannabis users and controls (all P > 0.05), whereas cannabis users demonstrated reduced peak apical rotation compared with controls (cannabis users: 5.5 ± 3.8, controls: 9.6 ± 1.5; P = 0.02). Cannabis users had higher cfPWV compared with controls (cannabis users: 5.8 ± 0.6 m/s, controls: 5.3 ± 0.7 m/s; P = 0.05), whereas FMD was similar between cannabis users and controls (cannabis users: 8.3 ± 3.3%, controls: 6.8 ± 3.6%; P = 0.7). Young, healthy, and cannabis users demonstrate altered cardiac mechanics and greater aortic stiffness. Further studies should explore causal links between cannabis smoking and altered cardiovascular function.NEW & NOTEWORTHY Recreational cannabis is the most widely used substance in the world, other than alcohol. Yet, the effects of cannabis use on cardiovascular function and health are not well understood. Our cross-sectional data demonstrate that young, ostensibly healthy cannabis users have greater arterial stiffness and altered cardiac mechanics compared to nonusers. These findings suggest that cannabis users may be at greater risk of the development of future cardiovascular disease.
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Affiliation(s)
- Christian P Cheung
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Alexandra M Coates
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Philip J Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jamie F Burr
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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5
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Cutruzzolà A, Irace C, Frazzetto M, Sabatino J, Gullace R, De Rosa S, Spaccarotella C, Concolino D, Indolfi C, Gnasso A. Functional and morphological cardiovascular alterations associated with neurofibromatosis 1. Sci Rep 2020; 10:12070. [PMID: 32694667 PMCID: PMC7374589 DOI: 10.1038/s41598-020-68908-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/30/2020] [Indexed: 11/26/2022] Open
Abstract
Subjects with Neurofibromatosis 1 (NF1) develop vascular complications. The protein product of the gene affected in NF1, neurofibromin, physiologically modulates endothelial function and preserves vascular and myocardial structure. Our study aimed to verify whether subjects with NF1 have early, preclinical abnormalities of carotid artery structure, brachial artery function, and cardiac function. We recruited 22 NF1 subjects without previous cardiovascular events and 22 healthy control subjects. All subjects underwent measurement of carotid artery intima-media thickness (IMT), evaluation of brachial artery endothelial function after ischemia and exercise, and cardiac function. Mean IMT was 543 ± 115 μ in NF1 subjects and 487 ± 70 μ in Controls (p < 0.01). Endothelial function was significantly dumped in NF1 subjects. The dilation after ischemia and exercise was respectively 7.5(± 4.8)% and 6.7(± 3.0)% in NF1 versus 10.5(± 1.2)% and 10.5(± 2.1)% in control subjects (p < 0.02; p < 0.002). Left ventricular systolic function assessed by Global Longitudinal Strain was significantly different between NF1 subjects and Controls: − 19.3(± 1.7)% versus − 21.5(± 2.7)% (p < 0.008). These findings demonstrate that NF1 patients have early morphological and functional abnormalities of peripheral arteries and systolic cardiac impairment and suggest the need for a tight cardiovascular risk evaluation and primary prevention in subjects with NF1.
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Affiliation(s)
- Antonio Cutruzzolà
- Dipartimento di Medicina Sperimentale e Clinica, University Magna Græcia, Viale Europa Località Germaneto, 88100, Catanzaro, Italy
| | - Concetta Irace
- Dipartimento di Scienze della Salute, University Magna Græcia, Catanzaro, Italy
| | - Marco Frazzetto
- Dipartimento di Scienze della Salute, University Magna Græcia, Catanzaro, Italy
| | - Jolanda Sabatino
- Dipartimento di Scienze Mediche e Chirurgiche, University Magna Græcia, Catanzaro, Italy.,Center of Cardiovascular Research, University Magna Graecia, Mediterranea Cardio Centro, Catanzaro, Napoli, Italy
| | - Rosa Gullace
- Dipartimento di Scienze della Salute, University Magna Græcia, Catanzaro, Italy
| | - Salvatore De Rosa
- Dipartimento di Scienze Mediche e Chirurgiche, University Magna Græcia, Catanzaro, Italy.,Center of Cardiovascular Research, University Magna Graecia, Mediterranea Cardio Centro, Catanzaro, Napoli, Italy
| | - Carmen Spaccarotella
- Center of Cardiovascular Research, University Magna Graecia, Mediterranea Cardio Centro, Catanzaro, Napoli, Italy
| | - Daniela Concolino
- Dipartimento di Scienze della Salute, University Magna Græcia, Catanzaro, Italy
| | - Ciro Indolfi
- Dipartimento di Scienze Mediche e Chirurgiche, University Magna Græcia, Catanzaro, Italy.,Center of Cardiovascular Research, University Magna Graecia, Mediterranea Cardio Centro, Catanzaro, Napoli, Italy
| | - Agostino Gnasso
- Dipartimento di Medicina Sperimentale e Clinica, University Magna Græcia, Viale Europa Località Germaneto, 88100, Catanzaro, Italy.
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Tremblay JC, Coombs GB, Howe CA, Vizcardo-Galindo GA, Figueroa-Mujíca RJ, Bermudez D, Tymko MM, Villafuerte FC, Ainslie PN, Pyke KE. Global Reach 2018: reduced flow-mediated dilation stimulated by sustained increases in shear stress in high-altitude excessive erythrocytosis. Am J Physiol Heart Circ Physiol 2019; 317:H991-H1001. [PMID: 31441692 DOI: 10.1152/ajpheart.00316.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Excessive erythrocytosis [EE; hemoglobin concentration (Hb) ≥ 21 g/dL in adult men] is a maladaptive high-altitude pathology associated with increased cardiovascular risk and reduced reactive hyperemia flow-mediated dilation (FMD); however, whether a similar impairment occurs in response to more commonly encountered sustained increases in shear stress [sustained stimulus (SS)-FMD] over a range of overlapping stimuli is unknown. We characterized SS-FMD in response to handgrip exercise in Andeans with and without EE in Cerro de Pasco, Peru (4,330 m). Andean highlanders with EE (n = 17, Hb = 23.2 ± 1.2 g/dL) and without EE (n = 23, Hb = 18.7 ± 1.9 g/dL) performed 3 min of rhythmic handgrip exercise at 20, 35, and 50% of maximum voluntary contraction (MVC). Duplex ultrasound was used to continuously record blood velocity and diameter in the brachial artery, and blood viscosity was measured to accurately calculate shear stress. Although baseline shear stress did not differ, Andeans with EE had 22% lower shear stress than Andeans without at 50% MVC (P = 0.004). At 35 and 50% MVC, SS-FMD was 2.1 ± 2.0 and 2.8 ± 2.7% in Andeans with EE compared with 4.1 ± 3.4 and 7.5 ± 4.5% in those without (P = 0.048 and P < 0.001). The stimulus-response slope (∆shear stress vs. ∆diameter) was lower in Andeans with EE compared with Andeans without (P = 0.028). This slope was inversely related to Hb in Andeans with EE (r2 = 0.396, P = 0.007). A reduced SS-FMD in response to small muscle mass exercise in Andeans with EE indicates a generalized reduction in endothelial sensitivity to shear stress, which may contribute to increased cardiovascular risk in this population.NEW & NOTEWORTHY High-altitude excessive erythrocytosis (EE; hemoglobin concentration ≥ 21 g/dL) is a maladaptation to chronic hypoxia exposure and is associated with increased cardiovascular risk. We examined flow-mediated dilation (FMD) in response to sustained elevations in shear stress achieved using progressive handgrip exercise [sustained stimulus (SS)-FMD] in Andean highlanders with and without EE at 4,330 m. Andeans with EE demonstrated lower SS-FMD compared with those without. Heightened hemoglobin concentration was related to lower SS-FMD in Andeans with EE.
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Affiliation(s)
- Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Geoff B Coombs
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Gustavo A Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Rómulo J Figueroa-Mujíca
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Daniela Bermudez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
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7
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King TJ, Pyke KE. Evidence of a limb- and shear stress stimulus profile-dependent impact of high-intensity cycling training on flow-mediated dilation. Appl Physiol Nutr Metab 2019; 45:135-145. [PMID: 31251889 DOI: 10.1139/apnm-2019-0151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Lower limb endurance training can improve conduit artery flow-mediated dilation (FMD) in response to transient increases in shear stress (reactive hyperemia; RH-FMD) in both the upper and lower limbs. Sustained increases in shear stress recruit a partially distinct transduction pathway and elicit a physiologically relevant FMD response (SS-FMD) that provides distinct information regarding endothelial function. However, the impact of training on SS-FMD is not well understood. The purpose of this study was to determine the impact of cycling training on handgrip exercise-induced brachial artery (BA) FMD (BA SS-FMD) and calf plantar-flexion-induced superficial femoral artery (SFA) FMD (SFA SS-FMD). RH-FMD was also assessed in both arteries. Twenty-eight young males were randomized to control (n = 12) or training (n = 16) groups. The training group cycled 30 min/day, 3 days/week for 4 weeks at 80% heart rate reserve. FMD was assessed in the BA and SFA before and after the intervention via Duplex ultrasound. Results are means ± SD. Training did not impact SS-FMD in either artery, and SFA RH-FMD was also unchanged (p > 0.05). When controlling for the shear rate stimulus via covariate analysis, BA RH-FMD improved in the training group (p = 0.05) (control - pre-intervention: 5.7% ± 2.4%, post-intervention: 5.3% ± 2.4%; training - pre-intervention: 5.4% ± 2.5%, post-intervention: 7.2% ± 2.4%). Thus, endurance training resulted in nonuniform adaptations to endothelial function, with an isolated impact on the BA's ability to transduce a transient increase in shear stress. Novelty Training did not alter SS-FMD in the arm or leg. RH-FMD was augmented in the arm only. Thus training adaptations were limb- and shear stress profile-specific.
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Affiliation(s)
- Trevor J King
- Cardiovascular Stress Response Lab, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.,Cardiovascular Stress Response Lab, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Lab, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
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8
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Tremblay JC, Williams JS, Pyke KE. Ramp and step increases in shear stress result in a similar magnitude of brachial artery flow-mediated dilation. Eur J Appl Physiol 2019; 119:611-619. [PMID: 30603795 DOI: 10.1007/s00421-018-4049-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/28/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE There is evidence that the endothelium is responsive to both the rate and magnitude of increases in shear stress. However, whether flow-mediated dilation stimulated by sustained increases in shear stress (SS-FMD) is rate sensitive in humans is unknown. The purpose of this investigation was to test whether ramp (gradual) and step (instantaneous) increases in shear stress elicit disparate SS-FMD. METHODS Young, healthy men (n = 18, age = 22 ± 2 years, body mass index = 25 ± 3 kg m-2) performed two 11-min bouts of rhythmic handgrip exercise; one with a 5.5-min ramp-increase in shear stress and one with an immediate step increase in shear stress. Ramp increases in shear stress were achieved through incremental increases in handgrip exercise intensity [increases of 4% maximum voluntary contraction (MVC) every 30 s for 5.5 min, ending at 44% MVC] and step increases in shear stress were achieved through a combination of arterial compression and commencing handgrip exercise at 44% MVC. RESULTS Shear rate was greater in the step versus ramp protocol in minutes 1-6, but not different thereafter. Similarly, SS-FMD was greater in the step versus ramp protocol during minutes 2-6, but similar in minutes 7-11 (minute 11: ramp 8.7 ± 4.6%; step 9.4 ± 3.6%; P = 0.343). SS-FMD continued to increase over time with maintenance of a steady shear stress stimulus (step minutes 2-11: 0.51 ± 0.36% min-1; ramp minutes 7-11: 0.64 ± 0.57% min-1; P = 0.259). CONCLUSIONS These findings indicate that in the brachial artery of humans, the magnitude of SS-FMD is determined by the magnitude and duration, but not the rate, of increases in shear stress.
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Affiliation(s)
- Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, 28 Division Street, Kingston, ON, K7L 3N6, Canada
| | - Jennifer S Williams
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, 28 Division Street, Kingston, ON, K7L 3N6, Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, 28 Division Street, Kingston, ON, K7L 3N6, Canada.
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9
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Tremblay JC, Stimpson TV, Pyke KE. Evidence of sex differences in the acute impact of oscillatory shear stress on endothelial function. J Appl Physiol (1985) 2018; 126:314-321. [PMID: 30382805 DOI: 10.1152/japplphysiol.00729.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Acutely imposed oscillatory shear stress (OSS) reduces reactive hyperemia flow-mediated dilation (RH-FMD) in conduit arteries of men; however, whether a similar impairment occurs in women or with FMD in response to a controlled, sustained shear stress stimulus (SS-FMD) is unknown. The purpose of this study was to determine the impact of OSS on RH-FMD and SS-FMD in men and women. OSS was provoked in the brachial artery using a 30-min forearm cuff inflation (70 mmHg). Healthy men [ n = 16, 25 yr (SD 3)] and women [ n = 16, 21 yr (SD 2)] completed the OSS intervention twice (separate days). Brachial artery endothelial function was assessed pre- and postintervention via either RH-FMD or 6 min of handgrip SS-FMD using Duplex ultrasound. The RH-FMD stimulus was calculated as shear rate area under the curve 60 s postdeflation (SRAUC60), whereas SS-FMD shear rate was targeted to produce a similar stimulus pre- and postintervention. The OSS intervention decreased RH-FMD in both sexes [men: 6.2% (SD 3.4) to 5.2% (SD 3.0); women: 5.4% (SD 2.0) to 3.1% (SD 1.8), P < 0.001), although this was accompanied by a reduced SRAUC60. There was no significant effect of the intervention on RH-FMD with SRAUC60 as a covariate ( P = 0.310). Handgrip exercise elicited a similar stimulus before and after the intervention ( P = 0.287) in men and women ( P = 0.873). Men demonstrated blunted SS-FMD [4.8% (SD 1.9) to 3.2% (SD 1.9), P < 0.001], whereas women displayed preserved SS-FMD following the intervention [3.5% (SD 1.9) to 4.0% (SD 1.9), P = 0.061]. The lower SS-FMD in men but not women following OSS provides evidence of sex differences in the effects of OSS on conduit artery endothelial function. NEW & NOTEWORTHY Acute exposure to oscillatory shear stress induces transient endothelial dysfunction in men; however, whether women experience similar impairments is unknown. Following acutely imposed oscillatory shear stress, there was a decrease in flow-mediated dilation stimulated by a physiologically relevant sustained increase in shear stress in men but not in premenopausal women. These findings demonstrate, for the first time in humans that there are sex differences in the impact of oscillatory shear stress on endothelial function.
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Affiliation(s)
- Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Taylor V Stimpson
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
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10
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McPhee IAC, Pyke KE. Thirty minutes of handgrip exercise potentiates flow-mediated dilatation in response to sustained and transient shear stress stimuli to a similar extent. Exp Physiol 2018; 103:1326-1337. [DOI: 10.1113/ep087065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/27/2018] [Indexed: 12/26/2022]
Affiliation(s)
- I. A. C. McPhee
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston Ontario Canada
| | - K. E. Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston Ontario Canada
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11
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Barbosa TC, Kaur J, Stephens BY, Akins JD, Keller DM, Brothers RM, Fadel PJ. Attenuated forearm vascular conductance responses to rhythmic handgrip in young African-American compared with Caucasian-American men. Am J Physiol Heart Circ Physiol 2018; 315:H1316-H1321. [PMID: 30118345 DOI: 10.1152/ajpheart.00387.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Previous studies have demonstrated that African-American (AA) individuals have heightened vasoconstrictor and reduced vasodilator responses under resting conditions compared with Caucasian-American (CA) individuals. However, potential differences in vascular responses to exercise remain unclear. Therefore, we tested the hypothesis that, compared with CA subjects, AA subjects would present an attenuated increase in forearm vascular conductance (FVC) during rhythmic handgrip exercise. Forearm blood flow (FBF; duplex Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured in healthy young CA ( n = 10) and AA ( n = 10) men during six trials of rhythmic handgrip performed at workloads of 4, 8, 12, 16, 20, and 24 kg. FVC (calculated as FBF/MAP), FBF, and MAP were similar between groups at rest (FVC: 63 ± 7 ml·min-1·100 mmHg-1 in CA subjects vs. 62 ± 7 ml·min-1·100 mmHg-1 in AA subjects, P = 0.862). There was an intensity-dependent increase in FVC during exercise in both groups; however, AA subjects presented lower FVC (interaction P < 0.001) at 8-, 12-, 16-, 20-, and 24-kg workloads (e.g., 24 kg: 324 ± 20 ml·min-1·100 mmHg-1 in CA subjects vs. 241 ± 21 ml·min-1·100 mmHg-1 in AA subjects, P < 0.001). FBF responses to exercise were also lower in AA subjects (interaction P < 0.001), whereas MAP responses did not differ between groups (e.g., ∆MAP at 24 kg: +19 ± 2 mmHg in CA subjects vs. +19 ± 2 mmHg in AA subjects, interaction P = 0.950). These findings indicate lower hyperemic responses to rhythmic handgrip exercise in AA men compared with CA men. NEW & NOTEWORTHY It is known that African-American individuals have heightened vasoconstriction and reduced vasodilation under resting conditions compared with Caucasian-American individuals. Here, we identified that the hyperemic response to moderate and high-intensity rhythmic handgrip exercise was lower in healthy young African-American men.
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Affiliation(s)
- Thales C Barbosa
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas
| | - Jasdeep Kaur
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas
| | - Brandi Y Stephens
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas
| | - John D Akins
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas
| | - David M Keller
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas
| | - R Matthew Brothers
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas
| | - Paul J Fadel
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas
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12
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Adler TE, Usselman CW, Takamata A, Stachenfeld NS. Blood pressure predicts endothelial function and the effects of ethinyl estradiol exposure in young women. Am J Physiol Heart Circ Physiol 2018; 315:H925-H933. [PMID: 29906227 DOI: 10.1152/ajpheart.00188.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hypertension, obesity, and endothelial function predict cardiovascular disease in women, and these factors are interrelated. We hypothesized that hypertension and obesity are associated with endothelial dysfunction in young women and that short-term ethinyl estradiol exposure mitigates this dysfunction. We examined flow-mediated dilation (FMD) responses before and during 7 days of oral ethinyl estradiol (30 µg/day) in 19 women (25 ± 5, 18-35 yr). We divided our sample into two groups based on two criteria: blood pressure and obesity. Women were divided into normal blood pressure (NBP; mean arterial pressure range: 78-91 mmHg, n = 7) and high blood pressure (HBP; mean arterial pressure range: 95-113 mmHg, n = 9) groups. We also stratified our subjects by body composition (lean: 18-31%, n = 8; obese: 38-59%, n = 9). We evaluated brachial FMD after two distinct shear stress stimuli: occlusion alone and occlusion with ischemic handgrip exercise. Obesity was unrelated to both FMD responses. Before ethinyl estradiol administration, the HBP group had blunted ischemic exercise responses relative to the NBP group (8.0 ± 3.5 vs. 12.3 ± 3.2%, respectively, P = 0.05). However, during ethinyl estradiol administration, ischemic exercise responses increased in the HBP group (12.8 ± 6.1%, P = 0.04) but decreased in the NBP group (5.6 ± 2.4%, P = 0.01). Standard FMD did not reveal differences between groups. In summary, 1) moderate HBP predicted endothelial impairment, 2) ethinyl estradiol administration had divergent effects on FMD in women with NBP versus HBP, and 3) enhanced FMD (ischemic handgrip exercise) revealed differences in endothelial function, whereas standard FMD (occlusion alone) did not. NEW & NOTEWORTHY We are the first to show that mild hypertension is a stronger predictor of endothelial dysfunction than obesity in healthy women without overt cardiovascular dysfunction. Importantly, the standard 5-min flow-mediated vasodilation stimulus did not detect endothelial dysfunction in our healthy population; only an enhanced ischemic handgrip exercise shear stress stimulus detected endothelial impairment. Estradiol administration increased flow-mediated dilation in women with high blood pressure, so it may be a therapeutic intervention to improve endothelial function.
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Affiliation(s)
| | - Charlotte W Usselman
- John B. Pierce Laboratory, New Haven, Connecticut.,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine , New Haven, Connecticut
| | - Akira Takamata
- Department of Environmental Health, Nara Women's University , Nara , Japan
| | - Nina S Stachenfeld
- John B. Pierce Laboratory, New Haven, Connecticut.,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine , New Haven, Connecticut
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13
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Zelt JT, Jones JH, Hirai DM, King TJ, Berton DC, Pyke KE, O'Donnell DE, Neder JA. Systemic vascular dysfunction is associated with emphysema burden in mild COPD. Respir Med 2018; 136:29-36. [PMID: 29501244 DOI: 10.1016/j.rmed.2018.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/22/2017] [Accepted: 01/11/2018] [Indexed: 01/07/2023]
Abstract
BACKGROUND Cardiovascular diseases play a major role in morbidity and mortality in the earlier stages of COPD. We hypothesized that systemic vascular dysfunction would be present even in patients who are currently considered at "low-risk" for negative cardiovascular outcomes, i.e., those with largely preserved FEV1, few exacerbations and only mild burden of respiratory symptoms (GOLD spirometric grade 1, clinical group A). METHODS 16 patients (FEV1 = 86 ± 13%) and 16 age- and gender-matched controls underwent measurements of: a) central arterial stiffness by pulse wave velocity, b) brachial flow-mediated dilation and c) forearm muscle oxygenation by near-infrared spectroscopy. Computed tomography quantified emphysema (% of low attenuation areas (LAA)) and airway disease. RESULTS Patients and controls were well matched for key clinical variables including co-morbidities burden. Thirteen patients presented with more than 5% LAA: emphysema extension was negatively related to transfer factor for carbon monoxide (TLCO) (r = -0.63; p = .01). Compared to controls, patients had higher central arterial stiffness, lower normalized (to shear stress) flow-mediated dilation, delayed time to peak flow-mediated dilation and poorer muscle oxygenation (p < .05). TLCO and emphysema, but not airway disease, were significantly related to each of these functional abnormalities (r values ranging from 0.51 to 0.66; p < .05). CONCLUSION Systemic vascular dysfunction is present in the earlier stages of COPD, particularly in patients with greater emphysema burden and low TLCO. Regardless FEV1, patients showing those structural and functional abnormalities might be at higher risk of negative events thereby deserving closer follow-up for early detection of cardiovascular disease.
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Affiliation(s)
- Joel T Zelt
- Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, Kingston, Canada
| | - Joshua H Jones
- Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, Kingston, Canada
| | - Daniel M Hirai
- Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, Kingston, Canada
| | - Trevor J King
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Danilo C Berton
- Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, Kingston, Canada; Division of Respirology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit (RIU), Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, Kingston, Canada
| | - J Alberto Neder
- Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, Kingston, Canada.
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14
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D'Urzo KA, King TJ, Williams JS, Silvester MD, Pyke KE. The impact of menstrual phase on brachial artery flow-mediated dilatation during handgrip exercise in healthy premenopausal women. Exp Physiol 2017; 103:291-302. [DOI: 10.1113/ep086311] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 10/25/2017] [Indexed: 12/29/2022]
Affiliation(s)
- Katrina A. D'Urzo
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston Ontario Canada
| | - Trevor J. King
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston Ontario Canada
| | - Jennifer S. Williams
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston Ontario Canada
| | - Morgan D. Silvester
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston Ontario Canada
| | - Kyra E. Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston Ontario Canada
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15
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Tremblay JC, Pyke KE. Flow-mediated dilation stimulated by sustained increases in shear stress: a useful tool for assessing endothelial function in humans? Am J Physiol Heart Circ Physiol 2017; 314:H508-H520. [PMID: 29167121 DOI: 10.1152/ajpheart.00534.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Investigations of human conduit artery endothelial function via flow-mediated vasodilation (FMD) have largely been restricted to the reactive hyperemia (RH) technique, wherein a transient increase in shear stress after the release of limb occlusion stimulates upstream conduit artery vasodilation (RH-FMD). FMD can also be assessed in response to sustained increases in shear stress [sustained stimulus (SS)-FMD], most often created with limb heating or exercise. Exercise in particular creates a physiologically relevant stimulus because shear stress increases, and FMD occurs, during typical day-to-day activity. Several studies have identified that various conditions and acute interventions have a disparate impact on RH-FMD versus SS-FMD, sometimes with only the latter demonstrating impairment. Indeed, evidence suggests that transient (RH) and sustained (SS) shear stress stimuli may be transduced via different signaling pathways, and, as such, SS-FMD and RH-FMD appear to offer unique insights regarding endothelial function. The present review describes the techniques used to assess SS-FMD and summarizes the evidence regarding 1) SS-FMD as an index of endothelial function in humans, highlighting comparisons with RH-FMD, and 2) potential differences in shear stress transduction and vasodilator production stimulated by transient versus sustained shear stress stimuli. The evidence suggests that SS-FMD is a useful tool to assess endothelial function and that further research is required to characterize the mechanisms involved and its association with long-term cardiovascular outcomes. NEW & NOTEWORTHY Sustained increases in peripheral conduit artery shear stress, created via distal skin heating or exercise, provide a physiologically relevant stimulus for flow-mediated dilation (FMD). Sustained stimulus FMD and FMD stimulated by transient, reactive hyperemia-induced increases in shear stress provide distinct assessments of conduit artery endothelial function.
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Affiliation(s)
- Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
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16
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Anyfanti P, Triantafyllidou E, Papadopoulos S, Triantafyllou A, Nikolaidis MG, Kyparos A, Vrabas IS, Douma S, Zafeiridis A, Dipla K. Smoking before isometric exercise amplifies myocardial stress and dysregulates baroreceptor sensitivity and cerebral oxygenation. ACTA ACUST UNITED AC 2017; 11:376-384. [DOI: 10.1016/j.jash.2017.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 04/02/2017] [Accepted: 04/05/2017] [Indexed: 11/15/2022]
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17
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King TJ, Schmitter SM, Pyke KE. Assessment of flow-mediated dilatation in the superficial femoral artery using a sustained shear stress stimulus via calf plantar-flexion exercise. Exp Physiol 2017; 102:725-737. [PMID: 28155247 DOI: 10.1113/ep085980] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/23/2017] [Indexed: 12/25/2022]
Abstract
NEW FINDINGS What is the central question of this study? The aim was to establish the ability of a newly designed leg exercise technique to produce sustained elevations in shear rate that stimulate flow-mediated dilatation (FMD) in the superficial femoral artery and to determine the repeat trial stability of the FMD response. What is the main finding and its importance? Calf plantar-flexion exercise can be used to increase shear stress and stimulate FMD in the superficial femoral artery. However, the magnitude of FMD varied systematically when multiple trials were repeated in short succession. The superficial femoral artery (SFA) is susceptible to vascular disease, and a technique to assess flow-mediated dilatation (FMD) in this vessel in response to a sustained shear stress stimulus could provide important information about endothelial function. The aim of this study was to establish the ability of a newly designed SFA leg exercise-FMD (LEX-FMD) technique to produce sustained elevations in shear rate, which stimulate FMD, and to determine the repeat trial stability of the FMD response. The SFA FMD stimulated by reactive hyperaemia (RH) and calf plantar-flexion exercise (LEX) was assessed via ultrasound in 19 healthy men (n = 10) and women (n = 9). The two experimental visits included either four trials of LEX-FMD or four trials of RH-FMD. The shear stress stimulus was estimated as the shear rate (blood velocity/SFA diameter). Results are expressed as the means ± SD. The LEX steady-state shear rate was consistent between trials (P = 0.176), whereas the RH shear rate area under the curve was higher in trial 1 versus trials 2-4 (P < 0.05). The %RH-FMD (four-trial mean 4.9 ± 2.5%) and absolute RH-FMD were not significantly different between trials (P = 0.465 and P = 0.359, respectively). Both %LEX-FMD and absolute LEX-FMD were higher during trial 3 (4.8 ± 3.4%) than trial 1 (3.6 ± 2.7%; P = 0.026 and P = 0.026, respectively). The magnitude of RH-FMD and LEX-FMD did not differ (P = 0.241). These results indicate that calf plantar-flexion exercise can be used to increase shear stress and stimulate FMD in the SFA. However, although SFA RH-FMD was stable across four trials, LEX-FMD varied systematically when multiple trials were repeated in rapid succession.
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Affiliation(s)
- T J King
- School of Kinesiology and Health studies, Queen's University, Kingston, Ontario, Canada
| | - S M Schmitter
- School of Kinesiology and Health studies, Queen's University, Kingston, Ontario, Canada
| | - K E Pyke
- School of Kinesiology and Health studies, Queen's University, Kingston, Ontario, Canada
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18
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Slattery DJ, Stuckless TJR, King TJ, Pyke KE. Impaired handgrip exercise-induced brachial artery flow-mediated dilation in young obese males. Appl Physiol Nutr Metab 2016; 41:528-37. [PMID: 26985988 DOI: 10.1139/apnm-2015-0459] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Flow mediated dilation (FMD) stimulated by different shear stress stimulus profiles may recruit distinct transduction mechanisms, and provide distinct information regarding endothelial function. The purpose of this study was to determine whether obesity influences brachial artery FMD differently depending on the shear stress profile used for FMD assessment. The FMD response to a brief, intermediate, and sustained shear stress profile was assessed in obese (n = 9) and lean (n = 19) young men as follows: brief stimulus, standard reactive hyperemia (RH) following a 5 min forearm occlusion (5 min RH); intermediate stimulus, RH following a 15 min forearm occlusion (15 min RH); sustained stimulus, 10 min of handgrip exercise (HGEX). Brachial artery diameter and mean shear stress were assessed using echo and Doppler ultrasound, respectively, during each FMD test. There was no group difference in HGEX shear stress (p = 0.390); however, the obese group had a lower HGEX-FMD (5.2 ± 3.0% versus 11.5 ± 4.4%, p < 0.001). There was no group difference in 5 min RH-FMD (p = 0.466) or 15 min RH-FMD (p = 0.181); however, the shear stress stimulus was larger in the obese group. After normalization to the stimulus the 15 min RH-FMD (p = 0.002), but not the 5 min RH-FMD (p = 0.118) was lower in the obese group. These data suggest that obesity may have a more pronounced impact on the endothelium's ability to respond to prolonged increases in shear stress.
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Affiliation(s)
- David J Slattery
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada.,Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Troy J R Stuckless
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada.,Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Trevor J King
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada.,Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada.,Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada
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19
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Stuckless TJR, Pyke KE. The impact of a cold pressor test on brachial artery handgrip exercise-induced flow-mediated dilation. Vasc Med 2015; 20:409-16. [DOI: 10.1177/1358863x15586473] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It is unknown how endothelial-dependent flow-mediated dilation (FMD) stimulated by a sustained, exercise-induced increase in shear stress (EX-FMD) is affected by a simultaneous sympathoexcitatory painful stimulus. The purpose of this study was to examine the impact of a cold pressor test (CPT) on brachial artery EX-FMD elicited by a handgrip exercise-induced increase in shear stress. Participants were healthy males (age 21±2 years) ( n=28; 16 Experimental group, 12 Control). Brachial artery diameter and blood velocity were measured using echo and Doppler ultrasound, respectively. Shear stress was estimated by shear rate (shear rate = blood velocity / diameter) and targeted to reach 75 s–1 in each of two EX-FMD trials in all subjects. In the Experimental group, the second EX-FMD trial was accompanied by simultaneous foot immersion in ice water (simultaneous CPT). The shear rate stimulus did not differ between groups ( p=0.823) or trials ( p=0.726) (group × trial interaction: p=0.646) (average exercise shear rate (mean ± SD): 67.6±6.2 s–1). The CPT (experienced during EX-FMD trial 2 in the Experimental group) increased mean arterial pressure ( p<0.001) and heart rate ( p=0.002) relative to the Control group. %EX-FMD was not different between groups ( p=0.508) or trials ( p=0.592) (group × trial interaction: p=0.879) (EX-FMD: Experimental group trial 1: 5.4±3.4%, trial 2: 5.6±2.6%; Control group trial 1: 6.0±3.7%, trial 2: 6.4±2.2%). In conclusion, the CPT did not impact concurrent EX-FMD, and this indicates that an acute painful stimulus does not interfere with conduit artery FMD responses during exercise in young healthy men.
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Affiliation(s)
- Troy JR Stuckless
- School of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario, Canada
| | - Kyra E Pyke
- School of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario, Canada
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