1
|
Ribeiro JAM, Oliveira SG, Ocamoto GN, Thommazo-Luporini LD, Mendes RG, Borghi-Silva A, Phillips SA, Billinger SA, Russo TL. Hemispheric lateralization, endothelial function, and arterial compliance in chronic post-stroke individuals: a cross-sectional exploratory study. Int J Neurosci 2024; 134:481-491. [PMID: 36028987 DOI: 10.1080/00207454.2022.2118597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 07/29/2022] [Accepted: 08/17/2022] [Indexed: 10/15/2022]
Abstract
Purpose/Aim: Cardiovascular function is controlled and regulated by a functional brain-heart axis. Although the exact mechanism is not fully understood, several studies suggest a hemispheric asymmetry in the neural control of cardiovascular function. Thus, the purpose of this study was to examine whether endothelial function and arterial compliance differ between individuals with left- and right-sided strokes.Materials and Methods: This was a cross-sectional exploratory study. Thirty individuals more than 6 months after stroke participated in the study. The endothelial function was assessed by ultrasound-measured flow-mediated dilation of the nonparetic arm brachial artery (baFMD). The arterial stiffness was assessed by measuring carotid-femoral pulse wave velocity (cfPWV) and central aortic pulse wave analysis [augmentation index (AIx), augmentation index normalized to a heart rate of 75 bpm (AIx@75) and reflection magnitude (RM)] using applanation tonometry. Results: Participants with right-sided stroke had worse endothelial function than those with left-sided stroke. This difference (baFMD = 2.51%) was significant (p = 0.037), and it represented a medium effect size (r = 0.38). Likewise, they had higher arterial stiffness than those with left-sided stroke. This difference (AIx = 10%; RM = 7%) was significant (p = 0.011; p = 0.012), and it represented a medium effect size (r = 0.48; r = 0.47).Conclusions: Our findings suggest that individuals with right-sided stroke have reduced endothelial function and arterial compliance compared to those with left-sided stroke. These data may indicate that those with right-sided strokes are more susceptible to cardiovascular events.
Collapse
Affiliation(s)
| | | | | | | | | | - Audrey Borghi-Silva
- Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil
| | - Shane A Phillips
- Department of Physical Therapy, University of Illinois at Chicago, Chicago, USA
| | - Sandra A Billinger
- Department of Neurology, University of Kansas Medical Center, Kansas City, USA
- KU Alzheimer's Disease Research Center, Fairway, KS, USA
| | - Thiago Luiz Russo
- Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil
| |
Collapse
|
2
|
López-Galán E, Vitón-Castillo AA, Carrazana-Escalona R, Planas-Rodriguez M, Fernández-García AA, Cutiño-Clavel I, Pascau-Simon A, Connes P, Sánchez-Hechavarría ME, Muñoz-Bustos GA. Autonomic and Vascular Responses during Reactive Hyperemia in Healthy Individuals and Patients with Sickle Cell Anemia. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1141. [PMID: 37374344 DOI: 10.3390/medicina59061141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 04/07/2023] [Accepted: 05/10/2023] [Indexed: 06/29/2023]
Abstract
Background and Objectives: To compare autonomic and vascular responses during reactive hyperemia (RH) between healthy individuals and patients with sickle cell anemia (SCA). Materials and Methods: Eighteen healthy subjects and 24 SCA patients were subjected to arterial occlusion for 3 min at the lower right limb level. The pulse rate variability (PRV) and pulse wave amplitude were measured through photoplethysmography using the Angiodin® PD 3000 device, which was placed on the first finger of the lower right limb 2 min before (Basal) and 2 min after the occlusion. Pulse peak intervals were analyzed using time-frequency (wavelet transform) methods for high-frequency (HF: 0.15-0.4) and low-frequency (LF: 0.04-0.15) bands, and the LF/HF ratio was calculated. Results: The pulse wave amplitude was higher in healthy subjects compared to SCA patients, at both baseline and post-occlusion (p < 0.05). Time-frequency analysis showed that the LF/HF peak in response to the post-occlusion RH test was reached earlier in healthy subjects compared to SCA patients. Conclusions: Vasodilatory function, as measured by PPG, was lower in SCA patients compared to healthy subjects. Moreover, a cardiovascular autonomic imbalance was present in SCA patients with high sympathetic and low parasympathetic activity in the basal state and a poor response of the sympathetic nervous system to RH. Early cardiovascular sympathetic activation (10 s) and vasodilatory function in response to RH were impaired in SCA patients.
Collapse
Affiliation(s)
- Erislandis López-Galán
- Departamento de Ciencias Básicas Biomédicas, Facultad de Medicina, Universidad de Ciencias Médicas de Santiago de Cuba, Santiago de Cuba 90100, Cuba
| | - Adrián Alejandro Vitón-Castillo
- Facultad de Ciencias Médicas "Dr. Ernesto Che Guevara de la Serna", Universidad de Ciencias Médicas de Pinar del Rio, Pinar del Rio 20100, Cuba
| | - Ramón Carrazana-Escalona
- Departamento de Ciencias Clínicas Básicas, Facultad de Medicina, Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile
| | - Maylet Planas-Rodriguez
- Departamento de Ciencias Básicas Biomédicas, Facultad de Medicina, Universidad de Ciencias Médicas de Santiago de Cuba, Santiago de Cuba 90100, Cuba
| | | | - Ileana Cutiño-Clavel
- Departamento de Ciencias Básicas Biomédicas, Facultad de Medicina, Universidad de Ciencias Médicas de Santiago de Cuba, Santiago de Cuba 90100, Cuba
| | - Alexander Pascau-Simon
- Hospital General "Dr. Juan Bruno Zayas Alfonso", Laboratorio Vascular no Invasivo, Santiago de Cuba 90400, Cuba
| | - Philippe Connes
- LIBM Laboratory, Team "Vascular Biology and Red Blood Cell", Claude Bernard University Lyon 1, 69622 Lyon, France
| | - Miguel Enrique Sánchez-Hechavarría
- Grupo Bio-Bio Complejidad, Departamento de Ciencias Clínicas y Preclínicas, Facultad de Medicina, Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile
- Núcleo Científico de Ciencias de la Salud, Facultad de Ciencias de la Salud, Universidad Adventista de Chile, Chillán 3780000, Chile
| | | |
Collapse
|
3
|
Fermoyle CC, La Salle DT, Alpenglow JK, Craig JC, Jarrett CL, Broxterman RM, McKenzie AI, Morgan DE, Birgenheier NM, Wray DW, Richardson RS, Trinity JD. Pharmacological modulation of adrenergic tone alters the vasodilatory response to passive leg movement in young but not in old adults. J Appl Physiol (1985) 2023; 134:1124-1134. [PMID: 36927146 PMCID: PMC10125034 DOI: 10.1152/japplphysiol.00682.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 03/18/2023] Open
Abstract
The age-related increase in α-adrenergic tone may contribute to decreased leg vascular conductance (LVC) both at rest and during exercise in the old. However, the effect on passive leg movement (PLM)-induced LVC, a measure of vascular function, which is markedly attenuated in this population, is unknown. Thus, in eight young (25 ± 5 yr) and seven old (65 ± 7 yr) subjects, this investigation examined the impact of systemic β-adrenergic blockade (propanalol, PROP) alone, and PROP combined with either α1-adrenergic stimulation (phenylephrine, PE) or α-adrenergic inhibition (phentolamine, PHEN), on PLM-induced vasodilation. LVC, calculated from femoral artery blood flow and pressure, was determined and PLM-induced Δ peak (LVCΔpeak) and total vasodilation (LVCAUC, area under curve) were documented. PROP decreased LVCΔpeak (PROP: 4.8 ± 1.8, Saline: 7.7 ± 2.7 mL·mmHg-1, P < 0.001) and LVCAUC (PROP: 1.1 ± 0.7, Saline: 2.4 ± 1.6 mL·mmHg-1, P = 0.002) in the young, but not in the old (LVCΔpeak, P = 0.931; LVCAUC, P = 0.999). PE reduced baseline LVC (PE: 1.6 ± 0.4, PROP: 2.3 ± 0.4 mL·min-1·mmHg-1, P < 0.01), LVCΔpeak (PE: 3.2 ± 1.3, PROP: 4.8 ± 1.8 mL·min-1·mmHg-1, P = 0.004), and LVCAUC (PE: 0.5 ± 0.4, PROP: 1.1 ± 0.7 mL·mmHg-1, P = 0.011) in the young, but not in the old (baseline LVC, P = 0.199; LVCΔpeak, P = 0.904; LVCAUC, P = 0.823). PHEN increased LVC at rest and throughout PLM in both groups (drug effect: P < 0.05), however LVCΔpeak was only improved in the young (PHEN: 6.4 ± 3.1, PROP: 4.4 ± 1.5 mL·min-1·mmHg-1, P = 0.004), and not in the old (P = 0.904). Furthermore, the magnitude of α-adrenergic modulation (PHEN - PE) of LVCΔpeak was greater in the young compared with the old (Young: 3.35 ± 2.32, Old: 0.40 ± 1.59 mL·min-1·mmHg-1, P = 0.019). Therefore, elevated α-adrenergic tone does not appear to contribute to the attenuated vascular function with age identified by PLM.NEW & NOTEWORTHY Stimulation of α1-adrenergic receptors eliminated age-related differences in passive leg movement (PLM) by decreasing PLM-induced vasodilation in the young. Systemic β-blockade attenuated the central hemodynamic component of the PLM response in young individuals. Inhibition of α-adrenergic receptors did not improve the PLM response in older individuals, though withdrawal of α-adrenergic modulation augmented baseline and maximal vasodilation in both groups. Accordingly, α-adrenergic signaling plays a role in modulating the PLM vasodilatory response in young but not in old adults, and elevated α-adrenergic tone does not appear to contribute to the attenuated vascular function with age identified by PLM.
Collapse
Affiliation(s)
- Caitlin C Fermoyle
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
| | - D Taylor La Salle
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Jeremy K Alpenglow
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Jesse C Craig
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
| | - Catherine L Jarrett
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
| | - Ryan M Broxterman
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Alec I McKenzie
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
| | - David E Morgan
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Nathaniel M Birgenheier
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
| | - D Walter Wray
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Russell S Richardson
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Joel D Trinity
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| |
Collapse
|
4
|
López-Galán E, Montoya-Pedrón A, Barrio-Deler R, Sánchez-Hechavarría ME, Muñoz-Bustos ME, Muñoz-Bustos GA. Reactive Hyperemia and Cardiovascular Autonomic Neuropathy in Type 2 Diabetic Patients: A Systematic Review of Randomized and Nonrandomized Clinical Trials. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59040770. [PMID: 37109728 PMCID: PMC10141598 DOI: 10.3390/medicina59040770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023]
Abstract
Objective: This work aimed to determine the relationship between the autonomic nervous system and reactive hyperemia (RH) in type 2 diabetes patients with and without cardiovascular autonomic neuropathy (CAN). Methodology: A systematic review of randomized and nonrandomized clinical studies characterizing reactive hyperemia and autonomic activity in type 2 diabetes patients with and without CAN was performed. Results: Five articles showed differences in RH between healthy subjects and diabetic patients with and/or without neuropathy, while one study did not show such differences between healthy subjects and diabetic patients, but patients with diabetic ulcers had lower RH index values compared to healthy controls. Another study found no significant difference in blood flow after a muscle strain that induced reactive hyperemia between normal subjects and non-smoking diabetic patients. Four studies measured reactive hyperemia using peripheral arterial tonometry (PAT); only two found a significantly lower endothelial-function-derived measure of PAT in diabetic patients than in those without CAN. Four studies measured reactive hyperemia using flow-mediated dilation (FMD), but no significant differences were reported between diabetic patients with and without CAN. Two studies measured RH using laser Doppler techniques; one of them found significant differences in the blood flow of calf skin after stretching between diabetic non-smokers and smokers. The diabetic smokers had neurogenic activity at baseline that was significantly lower than that of the normal subjects. The greatest evidence revealed that the differences in RH between diabetic patients with and without CAN may depend on both the method used to measure hyperemia and that applied for the ANS examination as well as the type of autonomic deficit present in the patients. Conclusions: In diabetic patients, there is a deterioration in the vasodilator response to the reactive hyperemia maneuver compared to healthy subjects, which depends in part on endothelial and autonomic dysfunction. Blood flow alterations in diabetic patients during RH are mainly mediated by sympathetic dysfunction. The greatest evidence suggests a relationship between ANS and RH; however, there are no significant differences in RH between diabetic patients with and without CAN, as measured using FMD. When the flow of the microvascular territory is measured, the differences between diabetics with and without CAN become evident. Therefore, RH measured using PAT may reflect diabetic neuropathic changes with greater sensitivity compared to FMD.
Collapse
Affiliation(s)
- Erislandis López-Galán
- Facultad de Medicina 2, Universidad de Ciencias Médicas de Santiago de Cuba, Santiago de Cuba 90100, Cuba
| | - Arquímedes Montoya-Pedrón
- Departamento de Neurofisiología Clínica, Hospital Clínico Quirúrgico Juan Brunos Zayas Alfonso, Universidad de Ciencias Médicas de Santiago de Cuba, Santiago de Cuba 90100, Cuba
| | - Rafael Barrio-Deler
- Hospital Infantil Norte Juan de la Cruz Martínez Maceira, Universidad de Ciencias Médicas de Santiago de Cuba, Santiago de Cuba 90100, Cuba
| | - Miguel Enrique Sánchez-Hechavarría
- Departamento de Ciencias Clínicas y Preclínicas, Facultad de Medicina, Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile
- Núcleo Científico de Ciencias de la Salud, Facultad de Ciencias de la Salud, Universidad Adventista de Chile, Chillán 3780000, Chile
| | - Mario Eugenio Muñoz-Bustos
- Departamento de Kinesiología, Facultad de Medicina, Universidad de Concepción, Concepción 4030000, Chile
| | - Gustavo Alejandro Muñoz-Bustos
- Escuela de Kinesiología, Facultad de Salud y Ciencias Sociales, Campus El Boldal, Sede Concepción, Universidad de las Américas, Concepcion 4030000, Chile
| |
Collapse
|
5
|
Alali MH, Lucas RAI, Junejo RT, Fisher JP. Impact of acute dynamic exercise and arterial shear rate modification on radial artery low-flow mediated constriction in young men. Eur J Appl Physiol 2022; 122:1885-1895. [PMID: 35551453 PMCID: PMC9287252 DOI: 10.1007/s00421-022-04963-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
Purpose Leg cycling exercise acutely augments radial artery low-flow mediated constriction (L-FMC). Herein, we sought to determine whether this is associated with exercise-induced changes in arterial shear rate (SR). Methods Ten healthy and recreationally active young men (23 ± 2 years) participated in 30 min of incremental leg cycling exercise (50, 100, 150 Watts). Trials were repeated with (Exercise + WC) and without (Exercise) the use of a wrist cuff (75 mmHg) placed distal to the radial artery to increase local retrograde SR while reducing mean and anterograde SR. Radial artery characteristics were measured throughout the trial, and L-FMC and flow mediated dilatation (FMD) were assessed before and acutely (~ 10 min) after leg cycling. Results Exercise increased radial artery mean and anterograde SR, along with radial artery diameter, velocity, blood flow and conductance (P < 0.05). Exercise + WC attenuated the exercise-induced increase in mean and anterograde SR (P > 0.05) but also increased retrograde SR (P < 0.05). In addition, increases in radial artery blood flow and diameter were reduced during Exercise + WC (Exercise + WC vs. Exercise, P < 0.05). After Exercise, L-FMC was augmented (− 4.4 ± 1.4 vs. − 13.1 ± 1.6%, P < 0.05), compared to no change in L-FMC after Exercise + WC (− 5.2 ± 2.0 vs. − 3.0 ± 1.6%, P > 0.05). In contrast, no change in FMD was observed in either Exercise or Exercise + WC trials (P > 0.05). Conclusions These findings indicate that increases in L-FMC following exercise are abolished by the prevention of increases radial artery diameter, mean and anterograde SR, and by elevation of retrograde SR, during exercise in young men.
Collapse
Affiliation(s)
- Mohammad H Alali
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Rebekah A I Lucas
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Rehan T Junejo
- Department of Life Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, United Kingdom
| | - James P Fisher
- Department of Physiology, Faculty of Medical and Health Sciences, Manaaki Manawa-The Centre for Heart Research, University of Auckland, 85 Park Road, Grafton, Auckland, 1142, New Zealand.
| |
Collapse
|
6
|
Habib K, Fallah B, Edgell H. Effect of Upright Posture on Endothelial Function in Women and Men. Front Physiol 2022; 13:846229. [PMID: 35399288 PMCID: PMC8988181 DOI: 10.3389/fphys.2022.846229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Women are more prone to orthostatic intolerance compared to men and have a greater vasodilatory capacity. We investigated the hypothesis that women would have greater peripheral flow-mediated dilation (FMD) while in the upright posture compared to men, which could contribute to this phenomenon. In young healthy women (age: 20 ± 3, BMI: 27 ± 5 kg/m2, n = 10) and men (age = 21 ± 2, BMI: 27 ± 8 kg/m2, n = 8), we assessed FMD of the brachial artery and hemodynamics to determine endothelial function during the supine and 70° head-up tilt postures (randomized). The brachial artery was kept at heart level in both trials. We observed that FMD increased in both sexes during tilt (Women: 11.9 ± 5.3 to 15.7 ± 5.6%; Men: 8.4 ± 3.2 to 14.6 ± 3.4%, Main effect of tilt p = 0.005) which was not due to changes in blood pressure or shear stress. There were no interaction effects between sex and posture. In a second cohort of women (age: 22 ± 3, BMI: 23 ± 3 kg/m2, n = 9) and men (age: 22 ± 2, BMI: 25 ± 8 kg/m2, n = 8), we investigated reactive hyperemia by peripheral arterial tonometry (LnRHI) via EndoPAT. Interestingly, we found that the EndoPAT response was decreased in both sexes during tilt (LnRHI: Men: 0.70 ± 0.28 to 0.59 ± 0.40, Women: 0.52 ± 0.23 to 0.30 ± 0.32, Main effect of tilt p = 0.037). We previously found that FMD is related to coronary responses to acetylcholine and adenosine whereas EndoPAT is related to coronary responses to dobutamine. Therefore, we suggest that sympathetic mediated dilation is attenuated in the upright posture while the increased vasodilatory response as measured by FMD in the tilt posture could be attributed to increasing metabolite production from postural muscles.
Collapse
Affiliation(s)
- Karim Habib
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Behzad Fallah
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Heather Edgell
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.,Muscle Health Research Center, York University, Toronto, ON, Canada
| |
Collapse
|
7
|
Miura K, Kashima H, Namura S, Morimoto M, Endo MY, Oue A, Fukuba Y. Effects of cooling or warming of the distal upper limb on skin vascular conductance and brachial artery shear profiles during cycling exercise. Res Sports Med 2021; 30:308-324. [PMID: 33472421 DOI: 10.1080/15438627.2021.1872573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The relative influence of skin vascular conductance in glabrous (G; palm) and non-glabrous (NG; dorsal and forearm) regions to upstream brachial artery-shear stress (BA-SS) profile are unknown. This study aimed to elucidate the effects of G and/or NG skin vascular conductance (VC), which were modulated by warming or cooling manipulation, on BA-shear rate (SR, an estimate of SS) during cycling exercise. Seven healthy subjects performed 60-min exercise. Between 20 and 50 min of the exercise, the NG+G or G skin region were warmed to 42°C or cooled to 15°C using a water bath. Throughout the protocol, diameter and blood velocity in BA and skin VCs in forearm and palm were measured. All measurements showed that a steady-state response was reached after 20 min of exercise. Subsequently, during cooling manipulation, forearm VC was significantly decreased, and the concomitant BA-SR profile was revealed (primarily characterized by decreased antegrade SR and increased retrograde SR) in the NG+G. Such changes were not observed in G alone. During warming manipulation, forearm VC and mean BA-SR significantly increased only in the NG+G. In conclusion, vascular response in NG skin possibly plays a major role in the modulation of BA-SS profile during cycling exercise.
Collapse
Affiliation(s)
- Kohei Miura
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan.,Department of Health and Nutrition, Faculty of Health Sciences, University of Hiroshima Shudo, Hiroshima, Japan
| | - Hideaki Kashima
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Saki Namura
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Marina Morimoto
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Masako Y Endo
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Anna Oue
- Faculty of Food and Nutritional Sciences, Toyo University, Gunma, Japan
| | - Yoshiyuki Fukuba
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| |
Collapse
|
8
|
Casey DP, Bock JM. Inorganic nitrate supplementation attenuates conduit artery retrograde and oscillatory shear in older adults. Am J Physiol Heart Circ Physiol 2021; 320:H991-H998. [PMID: 33449848 DOI: 10.1152/ajpheart.00843.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Aging causes deleterious changes in resting conduit artery shear patterns and reduced blood flow during exercise partially attributable to reduced nitric oxide (NO). Inorganic nitrate increases circulating NO bioavailability and may, therefore, improve age-associated changes in shear rate as well as exercise hyperemia. Ten older adults (age: 67 ± 3 yr) consumed 4.03 mmol nitrate and 0.29 mmol nitrite (active) or devoid of both (placebo) daily for 4 wk in a randomized, double-blinded, crossover fashion. Brachial artery diameter (D) and blood velocity (Vmean) were measured via Doppler ultrasound at rest for the characterization of shear profile as well as during two handgrip exercise trials (4 and 8 kg) for calculation of forearm blood flow (Vmean × cross-sectional area, FBF) and conductance [FBF/mean arterial pressure, forearm vascular conductance (FVC)]. Plasma [nitrate] and [nitrite] increased following active (P < 0.05 for both) but not placebo (P = 0.68 and 0.40, respectively) supplementation. Neither mean nor antegrade shear rate changed following either supplement (beverage-by-time P = 0.14 and 0.21, respectively). Retrograde (-13.4 ± 7.0 to -9.7 ± 6.8·s-1) and oscillatory (0.20 ± 0.08 to 0.15 ± 0.09 A.U., P < 0.05 for both) shear decreased following active, but not placebo (P = 0.81 and 0.70, respectively), supplementation. The FBF response (Δ from rest) to neither 4-kg nor 8-kg trials changed following either supplement (beverage-by-time P = 0.53 and 0.11, respectively). Similarly, no changes were observed in FVC responses to 4-kg or 8-kg trials (beverage-by-time P = 0.23 and 0.07, respectively). These data indicate that inorganic nitrate supplementation improves conduit artery shear profiles, but not exercise hyperemia, in older adults.NEW & NOTEWORTHY We report for the first time, to our knowledge, that 4 wk of inorganic nitrate supplementation attenuates retrograde and oscillatory shear in the brachial artery of older adults. However, this was not associated with greater hyperemic or vasodilatory responses to exercise. In sum, these data highlight favorable changes in shear patterns with aging, which may reduce the risk of atherosclerotic cardiovascular disease.
Collapse
Affiliation(s)
- Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joshua M Bock
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| |
Collapse
|
9
|
Alali MH, Vianna LC, Lucas RAI, Junejo RT, Fisher JP. Impact of whole body passive heat stress and arterial shear rate modification on radial artery function in young men. J Appl Physiol (1985) 2020; 129:1373-1382. [PMID: 33031019 DOI: 10.1152/japplphysiol.00296.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We sought to determine how whole body heating acutely influences radial artery function, characterized using flow-mediated dilation (FMD) and low-flow-mediated constriction (L-FMC), and the mechanistic role of shear rate modification on radial artery functional characteristics during heating. Eleven young healthy men underwent whole body heating (water-perfused suit) sufficient to raise the core temperature by +1°C. Trials were repeated with (heat + WC) and without (heat) the application of a wrist cuff located distal to the radial artery examined, known to prevent increases in mean and anterograde shear rates but increase retrograde shear rate. Radial artery characteristics were assessed throughout each trial, with FMD and L-FMC assessed before and upon reaching the target core temperature. Heat markedly increased radial artery mean and anterograde shear rates, along with radial artery diameter and blood flow (P < 0.05). Heat + WC abolished the heat-induced increase in mean and anterograde shear rates (P > 0.05) but markedly increased retrograde shear rate (P < 0.05). Concomitantly, increases in radial artery diameter and blood flow were decreased (heat + WC vs. heat, P < 0.05). Heat attenuated FMD (8.6 ± 1.2% vs. 2.2 ± 1.4%, P < 0.05), whereas no change in FMD was observed in heat + WC (7.8 ± 1.2% vs. 10.8 ± 1.2%, P > 0.05). In contrast, L-FMC was not different in either trial (P > 0.05). In summary, acute whole body heating markedly elevates radial artery shear rate, diameter, and blood flow and diminishes FMD. However, marked radial artery vasodilation and diminished FMD are absent when these shear rate changes are prevented. Shear rate modifications underpin the radial artery response to acute whole body heat stress, but further endothelium-dependent vasodilation (FMD) is attenuated likely as the vasodilatory range limit is approached.NEW & NOTEWORTHY We observed that acute whole body heating elevates radial artery shear rate, diameter, and blood flow. This results in a diminished flow-meditated dilatation (FMD) but does not change low-flow-mediated constriction (L-FMC). Preventing shear rate changes during whole body heating reduces radial artery vasodilation and reverses FMD reductions but has no effect on L-FMC. These findings indicate that shear rate changes underpin conduit artery responses to acute whole body heat stress, but further endothelium-dependent flow-mediated vasodilation is attenuated as the vasodilatory range limit is approached.
Collapse
Affiliation(s)
- Mohammad H Alali
- School of Sport, Exercise & Rehabilitation Sciences, College of Life & Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Lauro C Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Distrito Federal, Brazil
| | - Rebekah A I Lucas
- School of Sport, Exercise & Rehabilitation Sciences, College of Life & Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Rehan T Junejo
- Department of Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom.,Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, United Kingdom
| | - James P Fisher
- Faculty of Medical & Health Sciences, Department of Physiology, University of Auckland, Auckland, New Zealand
| |
Collapse
|
10
|
Coagulation Changes during Central Hypovolemia across Seasons. J Clin Med 2020; 9:jcm9113461. [PMID: 33121195 PMCID: PMC7692650 DOI: 10.3390/jcm9113461] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 11/17/2022] Open
Abstract
Lower body negative pressure (LBNP) application simulates hemorrhage. We investigated how seasons affect coagulation values at rest and during LBNP. Healthy participants were tested in cold (November–April) and warm (May–October) months. Following a 30-min supine period, LBNP was started at −10 mmHg and increased by −10 mmHg every five minutes until a maximum of −40 mmHg. Recovery was for 10 min. Blood was collected at baseline, end of LBNP, and end of recovery. Hemostatic profiling included standard coagulation tests, calibrated automated thrombogram, thrombelastometry, impedance aggregometry, and thrombin formation markers. Seven men (25.0 ± 3.6 years, 79.7 ± 7.8 kg weight, 182.4 ± 3.3 cm height, and 23.8 ± 2.3 kg/m2 BMI) and six women (25.0 ± 2.4 years, 61.0 ± 8.4 kg weight, 167 ± 4.7 cm height, and 21.8 ± 2.4 kg/m2 BMI) participated. Baseline levels of prothrombin (FII), tissue factor (TF) and markers for thrombin generation F1+2 and the thrombin/antithrombin complex (TAT) were higher during summer. Factor VIII, prothrombin fragment 1+2 (F1+2), TAT and the coagulation time showed significant increases during LBNP in both seasons. Some calibrated automated thrombography variables (Calibrated automated thrombography (CAT): lag, time to peak (ttPeak), peak) shifted in a procoagulant direction during LBNP in summer. Red blood cell counts (RBC), hemoglobin and white blood cell counts (WBC) decreased during LBNP. LBNP application reduced prothrombin time in winter and activated partial thromboplastin time in summer. Greater levels of FII, TF, F1+2, and TAT—a more pronounced LBNP-induced procoagulative effect, especially in CAT parameters (lag time (LT), Peak, ttPeak, Velindex)—were seen in summer. These results could have substantial medical implications.
Collapse
|
11
|
Sen S, Chandran DS, Jaryal AK, Deepak KK. The Low-Flow-Mediated Arterial Constriction in the Upper Limbs of Healthy Human Subjects are Artery Specific and Handedness Independent. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:1949-1959. [PMID: 32456806 DOI: 10.1016/j.ultrasmedbio.2020.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/26/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
Low-flow-mediated constriction (LFMC) has been used to assess resting endothelial function in peripheral conduit arteries. The literature describes discrepancies in the behaviour of radial versus brachial artery in response to low-flow state, the reasons for which were not addressed in a systematic and scientific way. Moreover, the influence of handedness on observed LFMC responses has not been investigated. The present study aimed at systematic measurement and comparison of the LFMC responses in radial and brachial arteries of both dominant and non-dominant arms of healthy human volunteers. We also investigated the physiological factors associated with differential LFMC response of radial versus brachial artery in the same group of subjects. Longitudinal B mode ultrasonographic cine loops of radial and brachial arteries were acquired at baseline and after producing distal circulatory arrest. Cine loops were screen grabbed and analyzed later using automated edge detection algorithms to measure end-diastolic diameters. Distal circulatory arrest was produced over the proximal forearm (for the brachial artery) and over the wrist (for the radial artery) at 250 mm Hg for 5 min after baseline measurements. Results suggested that arterial location (p = 0.0001) and baseline diameter (p < 0.0021) emerged as independent predictors of LFMC response. Differences in the LFMC responses are handedness independent and could be attributed to the arterial location along with the differences in their baseline diameters.
Collapse
Affiliation(s)
- Sakshi Sen
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Dinu S Chandran
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India.
| | - Ashok K Jaryal
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - K K Deepak
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| |
Collapse
|
12
|
Impact of acute mental stress on segmental arterial stiffness. Eur J Appl Physiol 2020; 120:2247-2257. [PMID: 32720134 DOI: 10.1007/s00421-020-04448-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 07/19/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE It has been reported that acute brief episodes of mental stress (MS) result in a prolonged increase in carotid-femoral pulse wave velocity (cfPWV), an index of aortic stiffness. However, whether acute MS also impacts arterial stiffness in other segments is unclear. The present study aimed to examine the impact of acute MS on segmental arterial stiffness. METHODS In the main experiment, 17 young male subjects (mean age, 20.1 ± 0.7 years) performed a 5-min MS and control (CON) task in a random order. Pulse wave velocity (PWV) from the heart to the brachium (hbPWV) and the ankle (haPWV), PWV between the brachial artery and the ankle (baPWV), and the cardio-ankle vascular index (CAVI) were simultaneously measured at baseline and 5, 15, and 30 min after the task. RESULTS Compared to baseline values, hbPWV, baPWV, haPWV, and CAVI significantly increased until 30 min after the MS task, whereas these variables did not significantly change following the CON task. At 5 and 30 min after the MS task, percentage changes from baseline were significantly higher in hbPWV (+ 5.2 ± 4.4 and 6.6 ± 4.9%) than in baPWV (+ 2.2 ± 2.1 and 2.2 ± 2.0%) or haPWV (+ 3.6 ± 2.6 and 4.3 ± 2.9%) and were also significantly lower in baPWV than in haPWV. CONCLUSION These findings suggest that acute MS elicits an increase in arterial stiffness in various segments and this arterial stiffening is not uniform among the segments.
Collapse
|
13
|
Bisconti AV, Cè E, Longo S, Venturelli M, Coratella G, Limonta E, Doria C, Rampichini S, Esposito F. Evidence for improved systemic and local vascular function after long-term passive static stretching training of the musculoskeletal system. J Physiol 2020; 598:3645-3666. [PMID: 32613634 DOI: 10.1113/jp279866] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/29/2020] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Vascular function and arterial stiffness are important markers of cardiovascular health and cardiovascular co-morbidity. Transitional phases of hypoemia and hypermia, with consequent fluctuations in shear rate, occuring during repetitive passive stretching adminstration (passive stretching training) may constitute an effective stimulus to induce an amelioration in vascular function, arterial stiffness and vascular remodelling by improving central and local blood flow control mechanisms. Vascular function, arterial stiffness and vascular remodelling were evaluated before and after 12 weeks of passive stretching training and after 6 weeks from training cessation, in the femoral, popliteal (treated with stretching), and brachial arteries (untreated) of both sides. After passive stretching training, vascular function and arterial remodelling improved, and arterial stiffness decreased in all the arteries, suggesting modifications of both central and local blood flow control mechanisms. Passive stretching-induced improvements related to central mechanisms seemed to have a short duration, as they returned to pre-training baseline within 6 weeks from training cessation, whereas those more related to a local mechanism persisted in the follow-up. ABSTRACT Acute passive stretching (PS) effects on blood flow ( Q ̇ ), shear rate ( Y ̇ ), and vascular function in the feeding arteries of the stretched muscle have been extensively investigated; however, few data are available on vascular adjustments induced by long-term PS training. We investigated the effects of PS training on vascular function and stiffness of the involved (femoral and popliteal) and uninvolved (brachial) arteries. Our hypothesis was that PS-induced changes in Q ̇ and Y ̇ would improve central and local mechanisms of Q ̇ control. Thirty-nine participants were randomly assigned to bilateral PS (n = 14), monolateral PS (n = 13) or no PS training (n = 12). Vascular function was measured before and after 12 weeks of knee extensor and plantar flexor muscles' PS training by single passive limb movement and flow-mediated dilatation (FMD). Central (carotid-femoral artery PWV, PWVCF ) and peripheral (carotid-radial artery PWV, PWVCR ) arterial stiffness was measured by pulse-wave velocity (PWV), together with systolic (SBP) and diastolic (DBP) blood pressure. After PS training, increases of 30%, 25% and 8% (P < 0.05) in femoral Δ Q ̇ , popliteal and brachial artery FMD%, respectively, occurred in both PS training groups. A decrease in PWVCF , PWVCR , SBP and DBP (-25%, -17%, -4% and -8%, respectively; P < 0.05) was noted. No changes occurred in controls. Vascular function improved and arterial stiffness reduced in the arteries involved and uninvolved with PS training, suggesting modifications in both central and local Q ̇ control mechanisms. PS-induced improvements had a short duration in some of vascular function parameters, as they returned to baseline within 6 weeks of PS training cessation.
Collapse
Affiliation(s)
- A V Bisconti
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy.,Department of Internal Medicine, The University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Centre, Veterans Affairs Medical Centre, Salt Lake City, UT, USA
| | - E Cè
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy.,IRCCS Galeazzi Orthopaedic Institute, Via Riccardo Galeazzi, 4, Milan, 20161, Italy
| | - S Longo
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy
| | - M Venturelli
- Department of Internal Medicine, The University of Utah, Salt Lake City, UT, USA.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - G Coratella
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy
| | - E Limonta
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy
| | - C Doria
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy
| | - S Rampichini
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy
| | - F Esposito
- Department of Biomedical Sciences for Health (SCIBIS), University of Milan, Milan, Italy.,IRCCS Galeazzi Orthopaedic Institute, Via Riccardo Galeazzi, 4, Milan, 20161, Italy
| |
Collapse
|
14
|
Miura K, Kashima H, Morimoto M, Namura S, Yamaoka Endo M, Oue A, Fukuba Y. Effects of Unilateral Arm Warming or Cooling on the Modulation of Brachial Artery Shear Stress and Endothelial Function during Leg Exercise in Humans. J Atheroscler Thromb 2020; 28:271-282. [PMID: 32595193 PMCID: PMC8049146 DOI: 10.5551/jat.55731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: We examined the effect of modulating the shear stress (SS) profile using forearm warming and cooling on subsequent endothelial function in the brachial artery (BA) during exercise. Methods: Twelve healthy young subjects immersed their right forearm in water (15°C or 42°C) during a leg cycling exercise at 120–130 bpm for 60 min. The same exercise without water immersion served as a control. The BA diameter and blood velocity were simultaneously recorded using Doppler ultrasonography to evaluate the antegrade, retrograde, and mean shear rates (SRs, an estimate of SS) before, during, and after exercise. The endothelial function in the right BA was evaluated using flow-mediated dilation (FMD) (%) using two-dimensional high-resolution ultrasonography before (baseline) and 15 and 60 min after exercise. Results: During exercise, compared with the control trial, higher antegrade and mean SRs and lower retrograde SRs were observed in the warm trial; conversely, lower antegrade and mean SRs and higher retrograde SRs were observed in the cool trial. At 15 min postexercise, no significant change was observed in the FMD from baseline in the warm (Δ%FMD: +1.6%, tendency to increase; p = 0.08) and control trials (Δ %FMD: +1.1%). However, in the cool trial, the postexercise FMD at 60 min decreased from baseline (Δ%FMD: −2.7%) and was lower than that of the warm (Δ%FMD: +1.5%) and control (Δ%FMD: +1.2%) trials. Accumulated changes in each SR during and after exercise were significantly correlated with postexercise FMD changes. Conclusion: Modulation of shear profiles in the BA during exercise appears to be associated with subsequent endothelial function.
Collapse
Affiliation(s)
- Kohei Miura
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima.,Department of Health and Nutrition, Faculty of Health Sciences, University of Hiroshima Shudo
| | - Hideaki Kashima
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Marina Morimoto
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Saki Namura
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Masako Yamaoka Endo
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Anna Oue
- Faculty of Food and Nutritional Sciences, Toyo University
| | - Yoshiyuki Fukuba
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| |
Collapse
|
15
|
Tymko MM, Lawley JS, Ainslie PN, Hansen AB, Hofstaetter F, Rainer S, Amin S, Moralez G, Gasho C, Vizcardo-Galindo G, Bermudez D, Villafuerte FC, Hearon CM. Global Reach 2018 Heightened α-Adrenergic Signaling Impairs Endothelial Function During Chronic Exposure to Hypobaric Hypoxia. Circ Res 2020; 127:e1-e13. [PMID: 32268833 DOI: 10.1161/circresaha.119.316053] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RATIONALE Chronic exposure to hypoxia is associated with elevated sympathetic nervous activity and reduced vascular function in lowlanders, and Andean highlanders suffering from excessive erythrocytosis (EE); however, the mechanistic link between chronically elevated sympathetic nervous activity and hypoxia-induced vascular dysfunction has not been determined. OBJECTIVE To determine the impact of heightened sympathetic nervous activity on resistance artery endothelial-dependent dilation (EDD), and endothelial-independent dilation, in lowlanders and Andean highlanders with and without EE. METHODS AND RESULTS We tested healthy lowlanders (n=9) at sea level (344 m) and following 14 to 21 days at high altitude (4300 m), and permanent Andean highlanders with (n=6) and without (n=9) EE at high altitude. Vascular function was assessed using intraarterial infusions (3 progressive doses) of acetylcholine (ACh; EDD) and sodium nitroprusside (endothelial-independent dilation) before and after local α+β adrenergic receptor blockade (phentolamine and propranolol). Intraarterial blood pressure, heart rate, and simultaneous brachial artery diameter and blood velocity were recorded at rest and during drug infusion. Changes in forearm vascular conductance were calculated. The main findings were (1) chronic hypoxia reduced EDD in lowlanders (changes in forearm vascular conductance from sea level: ACh1: -52.7±19.6%, ACh2: -25.4±38.7%, ACh3: -35.1±34.7%, all P≤0.02); and in Andeans with EE compared with non-EE (changes in forearm vascular conductance at ACh3: -36.4%, P=0.007). Adrenergic blockade fully restored EDD in lowlanders at high altitude, and normalized EDD between EE and non-EE Andeans. (2) Chronic hypoxia had no effect on endothelial-independent dilation in lowlanders, and no differences were detected between EE and non-EE Andeans; however, EID was increased in the non-EE Andeans after adrenergic blockade (P=0.012), but this effect was not observed in the EE Andeans. CONCLUSIONS These data indicate that chronic hypoxia reduces EDD via heightened α-adrenergic signaling in lowlanders and in Andeans with EE. These vascular mechanisms have important implications for understanding the physiological consequences of acute and chronic high altitude adaptation.
Collapse
Affiliation(s)
- Michael M Tymko
- From the Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada (M.M.T., P.N.A.).,Neurovascular Health Lab, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Canada (M.M.T.)
| | - Justin S Lawley
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Philip N Ainslie
- From the Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada (M.M.T., P.N.A.)
| | | | | | - Simon Rainer
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Sachin Amin
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX (G.M.)
| | | | | | | | | | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas (C.M.H.).,Department of Internal Medicine, University of Texas Southwestern Medical Center (C.M.H.)
| |
Collapse
|
16
|
Nardone M, Miner S, McCarthy M, Ardern CI, Edgell H. Noninvasive Microvascular Indices Reveal Peripheral Vascular Abnormalities in Patients With Suspected Coronary Microvascular Dysfunction. Can J Cardiol 2019; 36:1289-1297. [PMID: 32553821 DOI: 10.1016/j.cjca.2019.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/03/2019] [Accepted: 12/03/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Reactive hyperemia peripheral arterial tonometry and flow-mediated dilation are common noninvasive measures of peripheral vascular function. However, their relationship with the coronary circulation, particularly in coronary microvascular dysfunction (CMD), is unclear. Therefore, the purpose of this study is to compare these noninvasive measurements with coronary microvascular function after endothelial-independent, endothelial-dependent, and sympathetically mediated pharmacologic hyperemia. METHODS Forty-seven patients with suspected CMD completed peripheral and coronary assessments. The reactive hyperemia index was collected using the EndoPAT2000 device, whereas a subset of patients (n = 28) completed brachial artery flow-mediated dilation using duplex ultrasound. Coronary microvascular function was quantified using the resistance and flow responses to intravenous adenosine (140 μg/kg/min), dobutamine (40 μg/kg/min), and intracoronary acetylcholine (100 μg). Abnormal coronary microvascular responses to adenosine and/or acetylcholine were used to define CMD. RESULTS The reactive hyperemia index (No CMD: 0.85 ± 0.23 vs CMD: 0.61 ± 0.26, P < 0.05) and flow-mediated dilation (No CMD: 7.2 ± 2.3 vs CMD: 4.8 ± 3.1; P < 0.05) were attenuated in patients with CMD. Whereas the reactive hyperemia index was correlated with the resistance and flow responses to dobutamine (ρ = -0.44 and ρ = 0.39, respectively; P < 0.05), flow-mediated dilation was correlated with the resistance responses to both adenosine (ρ = -0.48; P < 0.05) and acetylcholine (ρ = -0.66; P < 0.05). Lastly, the reactive hyperemia index and flow-mediated dilation had sensitivities of 80% and 69% and specificities of 71% and 93%, respectively, for identifying patients with CMD. CONCLUSIONS Peripheral vascular function is attenuated in CMD, and noninvasive measurements are associated with coronary responses to pharmaceutical stimulation.
Collapse
Affiliation(s)
- Massimo Nardone
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Steven Miner
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada; Southlake Regional Health Centre, Newmarket, Ontario, Canada
| | - Mary McCarthy
- Southlake Regional Health Centre, Newmarket, Ontario, Canada
| | - Chris I Ardern
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Heather Edgell
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada; Southlake Regional Health Centre, Newmarket, Ontario, Canada.
| |
Collapse
|
17
|
Tymko MM, Tremblay JC, Bailey DM, Green DJ, Ainslie PN. The impact of hypoxaemia on vascular function in lowlanders and high altitude indigenous populations. J Physiol 2019; 597:5759-5776. [PMID: 31677355 DOI: 10.1113/jp277191] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/07/2019] [Indexed: 12/18/2022] Open
Abstract
Exposure to hypoxia elicits widespread physiological responses that are critical for successful acclimatization; however, these responses may induce apparent maladaptive consequences. For example, recent studies conducted in both the laboratory and the field (e.g. at high altitude) have demonstrated that endothelial function is reduced in hypoxia. Herein, we review the several proposed mechanism(s) pertaining to the observed reduction in endothelial function in hypoxia including: (i) changes in blood flow patterns (i.e. shear stress), (ii) increased inflammation and production of reactive oxygen species (i.e. oxidative stress), (iii) heightened sympathetic nerve activity, and (iv) increased red blood cell concentration and mass leading to elevated nitric oxide scavenging. Although some of these mechanism(s) have been examined in lowlanders, less in known about endothelial function in indigenous populations that have chronically adapted to environmental hypoxia for millennia (e.g. the Peruvian, Tibetan and Ethiopian highlanders). There is some evidence indicating that healthy Tibetan and Peruvian (i.e. Andean) highlanders have preserved endothelial function at high altitude, but less is known about the Ethiopian highlanders. However, Andean highlanders suffering from chronic mountain sickness, which is characterized by an excessive production of red blood cells, have markedly reduced endothelial function. This review will provide a framework and mechanistic model for vascular endothelial adaptation to hypoxia in lowlanders and highlanders. Elucidating the pathways responsible for vascular adaption/maladaptation to hypoxia has potential clinical implications for disease featuring low oxygen delivery (e.g. heart failure, pulmonary disease). In addition, a greater understanding of vascular function at high altitude will clinically benefit the global estimated 85 million high altitude residents.
Collapse
Affiliation(s)
- Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada.,Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
| | - Daniel J Green
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Australia.,Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| |
Collapse
|
18
|
Claydon VE, Moore JP, Greene ER, Appenzeller O, Hainsworth R. Evaluation of forearm vascular resistance during orthostatic stress: Velocity is proportional to flow and size doesn't matter. PLoS One 2019; 14:e0224872. [PMID: 31730662 PMCID: PMC6857923 DOI: 10.1371/journal.pone.0224872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/23/2019] [Indexed: 02/08/2023] Open
Abstract
Background The upright posture imposes a significant challenge to blood pressure regulation that is compensated through baroreflex-mediated increases in heart rate and vascular resistance. Orthostatic cardiac responses are easily inferred from heart rate, but vascular resistance responses are harder to elucidate. One approach is to determine vascular resistance as arterial pressure/blood flow, where blood flow is inferred from ultrasound-based measurements of brachial blood velocity. This relies on the as yet unvalidated assumption that brachial artery diameter does not change during orthostatic stress, and so velocity is proportional to flow. It is also unknown whether the orthostatic vascular resistance response is related to initial blood vessel diameter. Methods We determined beat-to-beat heart rate (ECG), blood pressure (Portapres) and vascular resistance (Doppler ultrasound) during a combined orthostatic stress test (head-upright tilting and lower body negative pressure) continued until presyncope. Participants were 16 men (aged 38.4±2.3 years) who lived permanently at high altitude (4450m). Results The supine brachial diameter ranged from 2.9–5.6mm. Brachial diameter did not change during orthostatic stress (supine: 4.19±0.2mm; tilt: 4.20±0.2mm; -20mmHg lower body negative pressure: 4.19±0.2mm, p = 0.811). There was no significant correlation between supine brachial artery diameter and the maximum vascular resistance response (r = 0.323; p = 0.29). Forearm vascular resistance responses evaluated using brachial arterial flow and velocity were strongly correlated (r = 0.989, p<0.00001) and demonstrated high equivalency with minimal bias (-6.34±24.4%). Discussion During severe orthostatic stress the diameter of the brachial artery remains constant, supporting use of brachial velocity for accurate continuous non-invasive orthostatic vascular resistance responses. The magnitude of the orthostatic forearm vascular resistance response was unrelated to the baseline brachial arterial diameter, suggesting that upstream vessel size does not matter in the ability to mount a vasoconstrictor response to orthostasis.
Collapse
Affiliation(s)
- V. E. Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail:
| | - J. P. Moore
- School of Sport, Health & Exercise Sciences, Bangor University, Bangor, Gwynedd, United Kingdom
| | - E. R. Greene
- Department of Biology and Chemistry, New Mexico Highlands University, Las Vegas, New Mexico, United States of America
| | - O. Appenzeller
- Department of Neurology, New Mexico Health Enhancement and Marathon Clinics Research Foundation, Albuquerque, New Mexico, United States of America
| | - R. Hainsworth
- Division of Cardiovascular and Neuronal Remodeling, Faculty of Medicine, University of Leeds, Leeds, United Kingdom
| |
Collapse
|
19
|
Acute hypotension attenuates brachial flow-mediated dilation in young healthy men. Eur J Appl Physiol 2019; 120:161-169. [PMID: 31701274 DOI: 10.1007/s00421-019-04260-0] [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] [Received: 07/19/2019] [Accepted: 11/01/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE This study aimed to test our hypothesis that acute hypotension attenuates brachial flow-mediated dilation (FMD) as an index of endothelial function in healthy humans. METHODS Twelve healthy men (21.8 ± 1.6 years, body mass index; 22.2 ± 1.6 kg/m2) participated in this study. Brachial FMD was measured in three trials: standardized FMD protocol (control trial), abrupt decrease in blood pressure (BP) via thigh cuff inflation-deflation (hypotension trial) and decrease in shear rate (SR) via a shortened forearm occlusion time (SR reduction trial). Brachial diameter and blood velocity were measured using Duplex ultrasound. RESULTS Mean arterial pressure during reactive hyperaemia showed a marked decrease in the hypotension trial (- 23.7 ± 6.0 mmHg), but not in the control and SR reduction trials. SR area under the curve was attenuated in the SR reduction trial (P < 0.001), but not in the control and hypotension trials (P = 0.316). Consequently, FMD was attenuated in the hypotension and SR reduction trials compared with that in the control trial (P = 0.003 and P = 0.043, respectively), and was attenuated to a greater extent in the hypotension trial compared with the SR reduction trial (P = 0.006; control, 6.9 ± 3.5%; hypotension, 3.5 ± 1.7%; SR reduction, 5.0 ± 2.2%). After adjusting FMD using SR, FMD remained attenuated in the hypotension trial (P = 0.014), but not in the SR reduction trial. CONCLUSION Our findings indicate that arterial pressure as well as sympathetic nervous system activation could be an important determinant of FMD. Blunted FMD of peripheral arteries may be a rational response to restore BP and/or prevent further reduction of BP following acute hypotension in healthy humans.
Collapse
|
20
|
Stamatelopoulos K, Georgiopoulos G, Athanasouli F, Nikolaou PE, Lykka M, Roussou M, Gavriatopoulou M, Laina A, Trakada G, Charakida M, Delialis D, Petropoulos I, Pamboukas C, Manios E, Karakitsou M, Papamichael C, Gatsiou A, Lambrinoudaki I, Terpos E, Stellos K, Andreadou I, Dimopoulos MA, Kastritis E. Reactive Vasodilation Predicts Mortality in Primary Systemic Light-Chain Amyloidosis. Circ Res 2019; 125:744-758. [PMID: 31401949 PMCID: PMC6784773 DOI: 10.1161/circresaha.119.314862] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Supplemental Digital Content is available in the text. Cardiac involvement and hypotension dominate the prognosis of light-chain amyloidosis (AL). Evidence suggests that there is also peripheral vascular involvement in AL but its prognostic significance is unknown.
Collapse
Affiliation(s)
- Kimon Stamatelopoulos
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.).,Newcastle Cardiovascular Disease Prevention Hub, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom (K. Stamatelopoulos, A.G., K. Stellos)
| | - Georgios Georgiopoulos
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.).,School of Biomedical Engineering and Imaging Sciences, King's College, London, United Kingdom (G.G., M.C.)
| | - Fani Athanasouli
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Panagiota-Efstathia Nikolaou
- National and Kapodistrian University of Athens, Faculty of Pharmacy, Department of Pharmaceutical Chemistry, Laboratory of Pharmacology, Panepistimiopolis, Zografou, Athens, Greece (P.E.N., I.A.)
| | - Marita Lykka
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Maria Roussou
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Maria Gavriatopoulou
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Aggeliki Laina
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Georgia Trakada
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Marietta Charakida
- School of Biomedical Engineering and Imaging Sciences, King's College, London, United Kingdom (G.G., M.C.)
| | - Dimitris Delialis
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Ioannis Petropoulos
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Constantinos Pamboukas
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Efstathios Manios
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Marina Karakitsou
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Christos Papamichael
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Aikaterini Gatsiou
- Newcastle Cardiovascular Disease Prevention Hub, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom (K. Stamatelopoulos, A.G., K. Stellos)
| | - Irene Lambrinoudaki
- National and Kapodistrian University of Athens 2nd Department of Obstetrics and Gynecology, Menopause Clinic, Aretaieio Hospital, Athens, Greece (I.L.)
| | - Evangelos Terpos
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Konstantinos Stellos
- Newcastle Cardiovascular Disease Prevention Hub, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom (K. Stamatelopoulos, A.G., K. Stellos).,Department of Cardiology, Freeman Hospital, Newcastle Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK (K. Stellos)
| | - Ioanna Andreadou
- National and Kapodistrian University of Athens, Faculty of Pharmacy, Department of Pharmaceutical Chemistry, Laboratory of Pharmacology, Panepistimiopolis, Zografou, Athens, Greece (P.E.N., I.A.)
| | - Meletios A Dimopoulos
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| | - Efstathios Kastritis
- From the Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Greece (K. Stamatelopoulos, G.G., F.A., M.L., M.R., M.G., A.L., G.T., D.D., I.P., C. Pamboukas, E.M., M.K., C. Papamichael, E.T., M.A.D., E.K.)
| |
Collapse
|
21
|
Doherty CJ, King TJ, Incognito AV, Lee JB, Shepherd AD, Cacoilo JA, Slysz JT, Burr JF, Millar PJ. Effects of dynamic arm and leg exercise on muscle sympathetic nerve activity and vascular conductance in the inactive leg. J Appl Physiol (1985) 2019; 127:464-472. [PMID: 31246555 DOI: 10.1152/japplphysiol.00997.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The influence of muscle sympathetic nerve activity (MSNA) responses on local vascular conductance during exercise are not well established. Variations in exercise mode and active muscle mass can produce divergent MSNA responses. Therefore, we sought to examine the effects of small- versus large-muscle mass dynamic exercise on vascular conductance and MSNA responses in the inactive limb. Thirty-five participants completed two study visits in a randomized order. During visit 1, superficial femoral artery (SFA) blood flow (Doppler ultrasound) was assessed at rest and during steady-state rhythmic handgrip (RHG; 1:1 duty cycle, 40% maximal voluntary contraction), one-leg cycling (17 ± 3% peak power output), and concurrent exercise at the same intensities. During visit 2, MSNA (contralateral fibular nerve microneurography) was acquired successfully in 12/35 participants during the same exercise modes. SFA blood flow increased during RHG (P < 0.0001) and concurrent exercise (P = 0.03) but not cycling (P = 0.91). SFA vascular conductance was unchanged during RHG (P = 0.88) but reduced similarly during concurrent and cycling exercise (both P < 0.003). RHG increased MSNA burst frequency (P = 0.04) without altering burst amplitude (P = 0.69) or total MSNA (P = 0.26). In contrast, cycling and concurrent exercise had no effects on MSNA burst frequency (both P ≥ 0.10) but increased burst amplitude (both P ≤ 0.001) and total MSNA (both P ≤ 0.007). Across all exercise modes, the changes in MSNA burst amplitude and SFA vascular conductance were correlated negatively (r = -0.43, P = 0.02). In summary, the functional vascular consequences of alterations in sympathetic outflow to skeletal muscle are most closely associated with changes in MSNA burst amplitude, but not frequency, during low-intensity dynamic exercise.NEW & NOTEWORTHY Low-intensity small- versus large-muscle mass exercise can elicit divergent effects on muscle sympathetic nerve activity (MSNA). We examined the relationships between changes in MSNA (burst frequency and amplitude) and superficial femoral artery (SFA) vascular conductance during rhythmic handgrip, one-leg cycling, and concurrent exercise in the inactive leg. Only changes in MSNA burst amplitude were inversely associated with SFA vascular conductance responses. This result highlights the functional importance of measuring MSNA burst amplitude during exercise.
Collapse
Affiliation(s)
- Connor J Doherty
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Trevor J King
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Anthony V Incognito
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jordan B Lee
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Andrew D Shepherd
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Joseph A Cacoilo
- Department of Kinesiology, University of Guelph-Humber, Toronto, Ontario, Canada
| | - Joshua T Slysz
- 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
| | - Philip J Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.,Toronto General Research Institute, Toronto General Hospital, Toronto, Ontario, Canada
| |
Collapse
|
22
|
Effect of external compression on femoral retrograde shear and microvascular oxygenation in exercise trained and recreationally active young men. Eur J Appl Physiol 2019; 119:1809-1818. [PMID: 31190212 DOI: 10.1007/s00421-019-04170-1] [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: 02/15/2019] [Accepted: 05/28/2019] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Retrograde shear causes endothelial damage and is pro-atherogenic. The purpose of our study was to examine the impact of vascular remodeling from habitual exercise training on acute changes in retrograde shear and microvascular oxygenation (SMO2) induced via 30 min of external compression. METHODS Participants included 11 exercise trained (ET) men (Division I track athletes; age 20 ± 3 years) and 18 recreationally active (RA) men (age 23 ± 5 years). Near-infrared spectroscopy (NIRS) was used to measure vastus medialis SMO2. Doppler-ultrasound was used to assess SFA intima-media thickness, diameter and flow velocity to derive retrograde shear. Vascular measures were made at baseline (BASELINE), during a sham condition (calf compression to 5 mmHg, SHAM) and during the experimental condition (calf compression to 60 mmHg, EXP). RESULTS Compared to RA, ET had larger SFA diameters (0.66 ± 0.06 vs 0.58 ± 0.06 cm, p < 0.05) and lower SFA IMT (0.33 ± 0.03 vs 0.36 ± 0.07 mm, p < 0.05). Retrograde shear increased similarly in both groups during EXP (p < 0.05) but ET men had lower overall retrograde shear during the conditions (BASELINE 75.8 ± 26.8 vs EXP 88.2 ± 16.9 s-1) compared to RA men (BASELINE 84.4 ± 23.3 vs EXP 106.4 ± 19.6 s-1p < 0.05). There was a similar increase in SMO2 from BASELINE to SHAM (ET + 8.1 ± 4.8 vs RA + 6.4 ± 9.7%) and BASELINE to EXP (ET + 8.7 ± 6.4 vs RA + 7.1 ± 9.0%) in both groups. CONCLUSION Beneficial vascular remodeling in ET men is associated with lower retrograde shear during external compression. Acute increases in retrograde shear with external compression do not detrimentally impact microvascular oxygenation.
Collapse
|
23
|
Garten RS, Darling A, Weggen J, Decker K, Hogwood AC, Michael A, Imthurn B, Mcintyre A. Aerobic training and vascular protection: Insight from altered blood flow patterns. Exp Physiol 2019; 104:1420-1431. [PMID: 31127657 DOI: 10.1113/ep087576] [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: 01/04/2019] [Accepted: 05/24/2019] [Indexed: 12/14/2022]
Abstract
NEW FINDING What is the central question of this study? This study sought to determine whether prior upper limb aerobic training can attenuate the vascular dysfunction resulting from negative alteration of blood flow patterns. What is the main finding and its importance? We demonstrated that the microvasculature of young men with prior upper limb aerobic training (rowing) was equally susceptible to negatively altered blood flow patterns when compared with untrained control subjects. This finding reveals that aerobic training does not provide adequate protection against this type of vascular insult, highlighting the importance of reducing known vascular insults regardless of training status. ABSTRACT Acute alteration of blood flow patterns can substantially reduce blood vessel function and, if consistently repeated, may chronically reduce vascular health. Aerobic exercise training is associated with improved vascular health, but it is not well understood whether aerobic training-induced vascular adaptations provide protection against acute vascular insults. This study sought to determine whether prior upper limb aerobic training can attenuate the vascular dysfunction resulting from an acute vascular insult (increased retrograde/oscillatory shear). Ten young arm-trained (AT) men (rowers; 22 ± 1 years of age) and 10 untrained (UT) male control subjects (21 ± 3 years of age) were recruited for this study. Subjects completed two brachial artery (BA) flow-mediated dilatation (FMD) tests separated by an acute bout of subdiastolic cuff inflation (SDCI) of the distal forearm. Brachial artery dilatation (normalized for the shear stimulus) and reactive hyperaemia evaluated during the BA FMD test were used to determine conduit artery and microvascular function, respectively. Data were presented as mean values ± SD. The AT group reported significantly greater whole body (peak oxygen uptake; P = 0.01) and forearm aerobic capacity (P < 0.001). The SDCI intervention significantly increased retrograde (P < 0.001) and oscillatory shear (P < 0.001) in both groups. After the SDCI, microvascular function (post-cuff release hyperaemia), but not conduit artery function (shear-induced BA dilatation), was significantly reduced from pre-SDCI values (P = 0.001) independent of group. This study revealed that young men with prior upper limb aerobic training, when compared with untrained control subjects, were equally susceptible to the microvascular dysfunction associated with an acute increase in retrograde/oscillatory shear.
Collapse
Affiliation(s)
- Ryan S Garten
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Ashley Darling
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Jennifer Weggen
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Kevin Decker
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Austin C Hogwood
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Austin Michael
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Brandon Imthurn
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Andrew Mcintyre
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| |
Collapse
|
24
|
Increase of Perfusion Index During Vascular Occlusion Test is Paradoxically Associated With Higher Mortality in Septic Shock After Fluid Resuscitation: A Prospective Study. Shock 2019; 51:605-612. [DOI: 10.1097/shk.0000000000001217] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
25
|
Homer AR, Owen N, Dunstan DW. Too much sitting and dysglycemia: Mechanistic links and implications for obesity. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.coemr.2018.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
26
|
Bisconti AV, Devoto M, Venturelli M, Bryner R, Olfert IM, Chantler PD, Esposito F. Respiratory muscle training positively affects vasomotor response in young healthy women. PLoS One 2018; 13:e0203347. [PMID: 30252845 PMCID: PMC6155502 DOI: 10.1371/journal.pone.0203347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/20/2018] [Indexed: 12/16/2022] Open
Abstract
Vasomotor response is related to the capacity of the vessel to maintain vascular tone within a narrow range. Two main control mechanisms are involved: the autonomic control of the sympathetic neural drive (global control) and the endothelial smooth cells capacity to respond to mechanical stress by releasing vasoactive factors (peripheral control). The aim of this study was to evaluate the effects of respiratory muscle training (RMT) on vasomotor response, assessed by flow-mediated dilation (FMD) and heart rate variability, in young healthy females. The hypothesis was that RMT could enhance the balance between sympathetic and parasympathetic neural drive and reduce vessel shear stress. Thus, twenty-four women were randomly assigned to either RMT or SHAM group. Maximal inspiratory mouth pressure and maximum voluntary ventilation were utilized to assess the effectiveness of the RMT program, which consisted of three sessions of isocapnic hyperventilation/ week for eight weeks, (twenty-four training sessions). Heart rate variability assessed autonomic balance, a global factor regulating the vasomotor response. Endothelial function was determined by measuring brachial artery vasodilation normalized by shear rate (%FMD/SR). After RMT, but not SHAM, maximal inspiratory mouth pressure and maximum voluntary ventilation increased significantly (+31% and +16%, respectively). Changes in heart rate variability were negligible in both groups. Only RMT exhibited a significant increase in %FMD/SR (+45%; p<0.05). These data suggest a positive effect of RMT on vasomotor response that may be due to a reduction in arterial shear stress, and not through modulation of sympatho-vagal balance.
Collapse
Affiliation(s)
- Angela Valentina Bisconti
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
- * E-mail:
| | - Michela Devoto
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Massimo Venturelli
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Italy
| | - Randall Bryner
- School of Medicine, Division of Exercise Physiology, West Virginia University, Morgantown (WV), United States of America
| | - I. Mark Olfert
- School of Medicine, Division of Exercise Physiology, West Virginia University, Morgantown (WV), United States of America
| | - Paul D. Chantler
- School of Medicine, Division of Exercise Physiology, West Virginia University, Morgantown (WV), United States of America
| | - F. Esposito
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
- IRCCS Galeazzi Orthopedic Institute, Milan, Italy
| |
Collapse
|
27
|
Tremblay JC, Hoiland RL, Carter HH, Howe CA, Stembridge M, Willie CK, Gasho C, MacLeod DB, Pyke KE, Ainslie PN. UBC-Nepal expedition: upper and lower limb conduit artery shear stress and flow-mediated dilation on ascent to 5,050 m in lowlanders and Sherpa. Am J Physiol Heart Circ Physiol 2018; 315:H1532-H1543. [PMID: 30168724 DOI: 10.1152/ajpheart.00345.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study of conduit artery endothelial adaptation to hypoxia has been restricted to the brachial artery, and comparisons with highlanders have been confounded by differences in altitude exposure, exercise, and unknown levels of blood viscosity. To address these gaps, we tested the hypothesis that lowlanders, but not Sherpa, would demonstrate decreased mean shear stress and increased retrograde shear stress and subsequently reduced flow-mediated dilation (FMD) in the upper and lower limb conduit arteries on ascent to 5,050 m. Healthy lowlanders (means ± SD, n = 22, 28 ± 6 yr) and Sherpa ( n = 12, 34 ± 11 yr) ascended over 10 days, with measurements taken on nontrekking days at 1,400 m (baseline), 3,440 m ( day 4), 4,371 m ( day 7), and 5,050 m ( day 10). Arterial blood gases, blood viscosity, shear stress, and FMD [duplex ultrasound of the brachial and superficial femoral arteries (BA and SFA, respectively)] were acquired at each time point. Ascent decreased mean and increased retrograde shear stress in the upper and lower limb of lowlanders and Sherpa. Although BA FMD decreased in lowlanders from 7.1 ± 3.9% to 3.8 ± 2.8% at 5,050 versus 1,400 m ( P < 0.001), SFA FMD was preserved. In Sherpa, neither BA nor SFA FMD were changed upon ascent to 5,050 m. In lowlanders, the ascent-related exercise may favorably influence endothelial function in the active limb (SFA); selective impairment in FMD in the BA in lowlanders is likely mediated via the low mean or high oscillatory baseline shear stress. In contrast, Sherpa presented protected endothelial function, suggesting a potential vascular aspect of high-altitude acclimatization/adaptation. NEW & NOTEWORTHY Upper and lower limb arterial shear stress and flow-mediated dilation (FMD) were assessed on matched ascent from 1,400 to 5,050 m in lowlanders and Sherpa. A shear stress pattern associated with vascular dysfunction/risk manifested in both limbs of lowlanders and Sherpa. FMD was impaired only in the upper limb of lowlanders. The findings indicate a limb-specific impact of high-altitude trekking on FMD and a vascular basis to acclimatization wherein endothelial function is protected in Sherpa on ascent.
Collapse
Affiliation(s)
- Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung, and Vascular Health, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Howard H Carter
- Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Connor A Howe
- Centre for Heart, Lung, and Vascular Health, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Mike Stembridge
- Cardiff Centre for Exercise and Health, Cardiff Metropolitan University , Cardiff , United Kingdom
| | - Christopher K Willie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Christopher Gasho
- Division of Pulmonary, Critical Care, Hyperbaric and Sleep Medicine, Loma Linda University School of Medicine , Loma Linda, California
| | - David B MacLeod
- Human Pharmacology and Physiology Laboratory, Department of Anesthesiology, Duke University Medical Center , Durham, North Carolina
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| |
Collapse
|
28
|
Hashimoto Y, Okamoto T. Acute effects of walking in water on vascular endothelial function and heart rate variability in healthy young men. Clin Exp Hypertens 2018; 41:452-459. [PMID: 30141976 DOI: 10.1080/10641963.2018.1506468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
AIM Aquatic exercise might improve endothelial function due to hydrostatic pressure increasing blood flow and causing shear stress to the endothelium. However, the acute effect of aerobic exercise in water on endothelial function is unclear. The present study compares the acute effect of aerobic exercise at moderate intensity in water and on land on endothelial function. METHODS Nine healthy young men walked on a treadmill for 30 min while immersed in water up to the xiphoid at 30.0 ± 0.2°C and on land at an intensity equivalent to 60% heart rate reserve in a crossover trial. Brachial artery flow-mediated dilation (FMD) was measured at baseline and at 30 and 60 min after exercise. Autonomic nervous activity was compared among conditions at the heart rate variability (HRV) during exercise. RESULTS FMD significantly decreased at 30 min after exercise on land trial (p < 0.05), but did not change after the aquatic trial. However, FMD was significantly higher after aquatic trial than land trial (p < 0.05) at 30 and 60 min after exercise, whereas heart rate, blood pressure, and HRV did not significantly differ between them. CONCLUSION These findings demonstrate that aerobic exercise in water suppressed the decrease in FMD compared with that on land, regardless of autonomic nervous activity.
Collapse
Affiliation(s)
- Yuto Hashimoto
- a Department of Health and Sport Science , Nippon Sport Science University , Tokyo , Japan
| | - Takanobu Okamoto
- b Department of Exercise Physiology , Nippon Sport Science University , Tokyo , Japan
| |
Collapse
|
29
|
Walsh LK, Restaino RM, Martinez-Lemus LA, Padilla J. Prolonged leg bending impairs endothelial function in the popliteal artery. Physiol Rep 2018; 5:5/20/e13478. [PMID: 29061865 PMCID: PMC5661238 DOI: 10.14814/phy2.13478] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 09/20/2017] [Indexed: 01/26/2023] Open
Abstract
Uninterrupted sitting blunts vascular endothelial function in the lower extremities; however, the factors contributing to this impairment remain largely unknown. Herein, we tested the hypothesis that prolonged flexion of the hip and knee joints, as it occurs during sitting, and associated low shear stress and disturbed (i.e., turbulent) blood flow caused by arterial bending, impairs endothelial function at the popliteal artery. Bilateral measurements of popliteal artery flow‐mediated dilation (FMD) were performed in 12 healthy subjects before and after a 3‐h lying‐down period during which one leg was bent (i.e., 90‐degree angles at the hip and knee) and the contralateral leg remained straight, serving as internal control. During the 3‐h lying down period, the bent leg displayed a profound and sustained reduction in popliteal artery blood flow and mean shear rate; whereas a slight but steady decline that only became significant at 3 h was noted in the straight leg. Notably, 3 h of lying down markedly impaired popliteal artery FMD in the bent leg (pre: 6.3 ± 1.2% vs. post: 2.8 ± 0.91%; P < 0.01) but not in the straight leg (pre: 5.6 ± 1.1% vs. post: 7.1 ± 1.2%; P = 0.24). Collectively, this study provides evidence that prolonged bending of the leg causes endothelial dysfunction in the popliteal artery. This effect is likely secondary to vascular exposure to low and disturbed blood flow resulting from arterial angulation. We conclude that spending excessive time with legs bent and immobile, irrespective of whether this is in the setting of sitting or lying‐down, may be disadvantageous for leg vascular health.
Collapse
Affiliation(s)
- Lauren K Walsh
- Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Robert M Restaino
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Luis A Martinez-Lemus
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Jaume Padilla
- Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri .,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Child Health University of Missouri, Columbia, Missouri
| |
Collapse
|
30
|
Elliott RO, Alsalahi S, Fisher JP. Impact of acute dynamic exercise on radial artery low-flow mediated constriction in humans. Eur J Appl Physiol 2018; 118:1463-1472. [PMID: 29748721 PMCID: PMC6028889 DOI: 10.1007/s00421-018-3876-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/26/2018] [Indexed: 01/22/2023]
Abstract
Purpose A “low-flow mediated constriction” (L-FMC) is evoked in the radial artery by the inflation of an ipsilateral wrist cuff to a supra-systolic pressure. We sought to test the hypothesis that the radial artery L-FMC response is augmented immediately following acute dynamic leg exercise in young healthy individuals. Methods Ten healthy and recreationally active men (23 ± 4 years) undertook a 30-min trial of incremental dynamic leg cycling exercise (10 min at 50, 100 and 150 W) and a 30-min time control trial (seated rest). Trials were randomly assigned and performed on separate days. Radial artery characteristics (diameter, blood flow and shear rate) were assessed throughout each trial, with L-FMC and flow-mediated vasodilatation (FMD) assessments conducted prior to and immediately following (10 min) trials. Results Dynamic leg cycling exercise increased radial artery blood flow, along with mean, retrograde and anterograde shear rate (P < 0.05). Blood flow profiles were unchanged during the time control trial (P > 0.05). Following exercise L-FMC was increased (mean [SD]; − 5.6 [3.3] vs. − 10.1 [3.8] %, P < 0.05), while it was not different in the time control condition (− 8.1 [3.2] vs. − 6.7 [3.4] %, P > 0.05). FMD was not different following either the exercise or time control trials (P > 0.05), but the composite end-point of L-FMC + FMD was enhanced post-exercise (P < 0.05). Conclusions Dynamic exercise with a large muscle mass acutely augments the vasoconstrictor response of the radial artery in response to a reduction in blood flow (L-FMC) in young healthy individuals. The time course of this post-exercise response and the underlying vasoregulatory mechanisms require elucidation.
Collapse
Affiliation(s)
- Robert O Elliott
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Sultan Alsalahi
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - James P Fisher
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.
| |
Collapse
|
31
|
Flow experience and the mobilization of attentional resources. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2018; 18:810-823. [DOI: 10.3758/s13415-018-0606-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
32
|
Iwamoto E, Bock JM, Casey DP. Blunted shear-mediated dilation of the internal but not common carotid artery in response to lower body negative pressure. J Appl Physiol (1985) 2018; 124:1326-1332. [DOI: 10.1152/japplphysiol.01011.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Shear-mediated dilation in peripheral conduit arteries is blunted with sympathetic nervous system (SNS) activation; however, the effect of SNS activation on shear-mediated dilation in carotid arteries is unknown. We hypothesized that SNS activation reduces shear-mediated dilation in common and internal carotid arteries (CCA and ICA, respectively), and this attenuation is greater in the ICA compared with the CCA. Shear-mediated dilation in the CCA and ICA were measured in nine healthy men (24 ± 1 yr) with and without SNS activation. Shear-mediated dilation was induced by 3 min of hypercapnia (end‐tidal partial pressure of carbon dioxide +10 mmHg from individual baseline); SNS activity was increased with lower body negative pressure (LBNP; −20 mmHg). CCA and ICA measurements were made using Doppler ultrasound during hypercapnia with (LBNP) or without (Control) SNS activation. LBNP trials began with 5 min of LBNP with subjects breathing hypercapnic gas during the final 3 min. Shear-mediated dilation was calculated as the percent rise in peak diameter from baseline diameter. Sympathetic activation attenuated shear-mediated dilation in the ICA (Control vs. LBNP, 5.5 ± 0.7 vs. 1.8 ± 0.4%, P < 0.01), but not in the CCA (5.1 ± 1.2 vs. 4.2 ± 1.0%, P = 0.31). Moreover, absolute reduction in shear-mediated dilation via SNS activation was greater in the ICA than the CCA (−3.6 ± 0.7 vs. −0.9 ± 0.8%, P = 0.02). Our data indicate that shear-mediated dilation is attenuated during LBNP to a greater extent in the ICA compared with the CCA. These results potentially provide insight into the role of SNS activation on cerebral perfusion, as the ICA is a key supplier of blood to the brain. NEW & NOTEWORTHY We explored the effect of acute sympathetic nervous system (SNS) activation on shear-mediated dilation in the common and internal carotid arteries (CCA and ICA, respectively) in young healthy men. Our data demonstrate that hypercapnia-induced vasodilation of the ICA is attenuated during lower body negative pressure to a greater extent than the CCA. These data may provide novel information related to the role of SNS activation on cerebral perfusion in humans.
Collapse
Affiliation(s)
- Erika Iwamoto
- Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
- School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Joshua M. Bock
- Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Darren P. Casey
- Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
- Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
- Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| |
Collapse
|
33
|
Tremblay JC, Howe CA, Ainslie PN, Pyke KE. UBC-Nepal Expedition: imposed oscillatory shear stress does not further attenuate flow-mediated dilation during acute and sustained hypoxia. Am J Physiol Heart Circ Physiol 2018. [PMID: 29522371 DOI: 10.1152/ajpheart.00717.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Experimentally induced oscillatory shear stress (OSS) and hypoxia reduce endothelial function in humans. Acute and sustained hypoxia may cause increases in resting OSS; however, whether this influences endothelial susceptibility to further increases in OSS is unknown. Healthy lowlanders ( n = 15, 30 ± 6 yr; means ± SD) participated in three OSS interventions: two interventions at sea level [normoxia and after 20 min of normobaric hypoxia (acute hypoxia, 11% O2)] and one intervention 5-7 days after a 9-day ascent to 5,050 m (sustained hypoxia). OSS was provoked in the brachial artery using a 30-min distal cuff inflation (75 mmHg). Endothelial function was assessed before and after each intervention by reactive hyperemia flow-mediated dilation (FMD). Shear stress magnitude and patterns were obtained via Duplex ultrasound. Baseline retrograde shear stress and OSS were greater in acute hypoxia versus normoxia ( P < 0.001), and OSS was elevated in sustained hypoxia versus normoxia ( P = 0.011). The intervention further augmented OSS during each condition. Preintervention FMD was decreased by 29 ± 48% in acute hypoxia and by 25 ± 31% in sustained hypoxia compared with normoxia ( P = 0.001 and 0.026); these changes correlated with changes in baseline mean and antegrade shear stress. After the intervention, FMD decreased during normoxia (-41 ± 26%, P < 0.001) and was unaltered during acute or sustained hypoxia. Therefore, a 30-min exposure to OSS reduced FMD during normoxia, a condition with an unchallenged, healthy endothelium; however, imposed OSS did not appear to worsen endothelial function during acute or sustained hypoxia. Exposure to an altered magnitude and pattern of shear stress at baseline in hypoxia may contribute to the insensitivity to further acute augmentation of OSS. NEW & NOTEWORTHY We investigated whether the endothelium remains sensitive to experimental increases in oscillatory shear stress in acute (11% O2) and sustained (2 wk at 5,050 m) hypoxia. Hypoxia altered baseline shear stress and decreased endothelial function (flow-mediated dilation); however, exposure to experimentally induced oscillatory shear stress only impaired flow-mediated dilation in normoxia.
Collapse
Affiliation(s)
- Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Connor A Howe
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| |
Collapse
|
34
|
Correlation between endothelial dysfunction and myocardial damage in acute phase of Tako-Tsubo cardiomyopathy: brachial flow mediated dilation as a potential marker for assessment of patient with Tako-Tsubo. Heart Vessels 2017; 33:291-298. [DOI: 10.1007/s00380-017-1062-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 10/06/2017] [Indexed: 02/07/2023]
|
35
|
Tymko MM, Tremblay JC, Steinback CD, Moore JP, Hansen AB, Patrician A, Howe CA, Hoiland RL, Green DJ, Ainslie PN. UBC-Nepal Expedition: acute alterations in sympathetic nervous activity do not influence brachial artery endothelial function at sea level and high altitude. J Appl Physiol (1985) 2017; 123:1386-1396. [PMID: 28860174 DOI: 10.1152/japplphysiol.00583.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/09/2017] [Accepted: 08/25/2017] [Indexed: 01/08/2023] Open
Abstract
Evidence indicates that increases in sympathetic nervous activity (SNA), and acclimatization to high altitude (HA), may reduce endothelial function as assessed by brachial artery flow-mediated dilatation (FMD); however, it is unclear whether such changes in FMD are due to direct vascular constraint, or consequential altered hemodynamics (e.g., shear stress) associated with increased SNA as a consequence of exposure to HA. We hypothesized that 1) at rest, SNA would be elevated and FMD would be reduced at HA compared with sea-level (SL); and 2) at SL and HA, FMD would be reduced when SNA was acutely increased, and elevated when SNA was acutely decreased. Using a novel, randomized experimental design, brachial artery FMD was assessed at SL (344 m) and HA (5,050 m) in 14 participants during mild lower-body negative pressure (LBNP; -10 mmHg) and lower-body positive pressure (LBPP; +10 mmHg). Blood pressure (finger photoplethysmography), heart rate (electrocardiogram), oxygen saturation (pulse oximetry), and brachial artery blood flow and shear rate (Duplex ultrasound) were recorded during LBNP, control, and LBPP trials. Muscle SNA was recorded (via microneurography) in a subset of participants (n = 5). Our findings were 1) at rest, SNA was elevated (P < 0.01), and absolute FMD was reduced (P = 0.024), but relative FMD remained unaltered (P = 0.061), at HA compared with SL; and 2) despite significantly altering SNA with LBNP (+60.3 ± 25.5%) and LBPP (-37.2 ± 12.7%) (P < 0.01), FMD was unaltered at SL (P = 0.448) and HA (P = 0.537). These data indicate that acute and mild changes in SNA do not directly influence brachial artery FMD at SL or HA.NEW & NOTEWORTHY The role of the sympathetic nervous system on endothelial function remains unclear. We used lower-body negative and positive pressure to manipulate sympathetic nervous activity at sea level and high altitude and measured brachial endothelial function via flow-mediated dilation. We found that acutely altering sympathetic nervous activity had no effect on endothelial function.
Collapse
Affiliation(s)
- Michael M Tymko
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada;
| | - Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Craig D Steinback
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Jonathan P Moore
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, United Kingdom
| | - Alex B Hansen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | | | - Connor A Howe
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Daniel J Green
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia, Australia; and.,Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| |
Collapse
|
36
|
Tymko MM, Tremblay JC, Hansen AB, Howe CA, Willie CK, Stembridge M, Green DJ, Hoiland RL, Subedi P, Anholm JD, Ainslie PN. The effect of α 1 -adrenergic blockade on post-exercise brachial artery flow-mediated dilatation at sea level and high altitude. J Physiol 2016; 595:1671-1686. [PMID: 28032333 DOI: 10.1113/jp273183] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 11/01/2016] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS Our objective was to quantify endothelial function (via brachial artery flow-mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate-intensity cycling exercise with and without administration of an α1 -adrenergic blockade. Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise. At sea level, endothelial function decreased following 30 min of moderate-intensity exercise, and this decrease was abolished with α1 -adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate-intensity exercise, and administration of α1 -adrenergic blockade resulted in an increase in flow-mediated dilatation. Our data indicate that post-exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high-altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. ABSTRACT We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate-intensity exercise at both sea level and high altitude are mediated via an α1 -adrenergic pathway. In a double-blinded, counterbalanced, randomized and placebo-controlled design, nine healthy participants performed a maximal-exercise test, and two 30 min sessions of semi-recumbent cycling exercise at 50% peak output following either placebo or α1 -adrenergic blockade (prazosin; 0.05 mg kg -1 ). These experiments were completed at both sea-level (344 m) and high altitude (3800 m). Blood pressure (finger photoplethysmography), heart rate (electrocardiogram), oxygen saturation (pulse oximetry), and brachial artery blood flow and shear rate (ultrasound) were recorded before, during and following exercise. Endothelial function assessed by brachial artery flow-mediated dilatation (FMD) was measured before, immediately following and 60 min after exercise. Our findings were: (1) at rest, FMD remained unchanged between sea level and high altitude (placebo P = 0.287; prazosin: P = 0.110); (2) FMD remained unchanged after maximal exercise at sea level and high altitude (P = 0.244); and (3) the 2.9 ± 0.8% (P = 0.043) reduction in FMD immediately after moderate-intensity exercise at sea level was abolished via α1 -adrenergic blockade. Conversely, at high altitude, FMD was unaltered following moderate-intensity exercise, and administration of α1 -adrenergic blockade elevated FMD (P = 0.032). Our results suggest endothelial function is differentially affected by exercise when exposed to hypobaric hypoxia. These findings have implications for understanding the chronic impacts of hypoxaemia on exercise, and the interactions between the α1 -adrenergic pathway and endothelial function.
Collapse
Affiliation(s)
- Michael M Tymko
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Alex B Hansen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Connor A Howe
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Chris K Willie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Mike Stembridge
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, UK
| | - Daniel J Green
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia, Australia.,Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - Ryan L Hoiland
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Prajan Subedi
- Pulmonary/Critical Care Section, Medical Service, VA Loma Linda Healthcare System, Loma Linda, CA, USA
| | - James D Anholm
- Pulmonary/Critical Care Section, Medical Service, VA Loma Linda Healthcare System, Loma Linda, CA, USA
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| |
Collapse
|
37
|
Tremblay JC, Thom SR, Yang M, Ainslie PN. Oscillatory shear stress, flow-mediated dilatation, and circulating microparticles at sea level and high altitude. Atherosclerosis 2016; 256:115-122. [PMID: 28010936 DOI: 10.1016/j.atherosclerosis.2016.12.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/25/2016] [Accepted: 12/01/2016] [Indexed: 12/01/2022]
Abstract
BACKGROUND AND AIMS Exposing the endothelium to acute periods of imposed oscillatory shear stress reduces endothelial function and elevates circulating microparticles (MPs). Oscillatory shear stress may be especially pathogenic when superimposed on hypoxia, an environmental stimulus that disrupts the endothelial milieu. We examined the effects of acute manipulation of oscillatory shear stress on endothelial function and circulating MPs at sea level (SL) and high altitude (HA). METHODS Healthy adults (n = 12) participated, once at SL and once on the second or third day at HA (3800 m). Oscillatory shear stress was provoked using a 30-min distal cuff occlusion intervention (75 mmHg). Endothelial function was assessed before and immediately after the intervention in the brachial artery by reactive hyperaemia flow-mediated dilatation (FMD). Venous blood samples of MPs (flow cytometry) were obtained before and during the last five minutes of the shear intervention. RESULTS At baseline, circulating MPs were two-fold higher at HA (p = 0.011) and brachial artery diameter was constricted (p = 0.015). Although the intervention at SL increased endothelial-derived MPs by 83 ± 39% (mean ± SEM; p = 0.021), FMD was unaltered. Conversely, at HA, the intervention elicited a 26 ± 11% reduction in FMD (p = 0.020); this reduction was inversely correlated with the change in total circulating MPs (r = -0.737, p = 0.006) and the change in endothelial-derived MPs (r = -0.614, p = 0.034). CONCLUSIONS The vascular endothelium appears to be susceptible to periods of oscillatory shear stress at HA, where impairments in endothelium-dependent vasodilatation may be amplified by endothelial injury. These findings have important implications for understanding the early impact of clinical situations of hypoxaemia on the vascular endothelium.
Collapse
Affiliation(s)
- Joshua C Tremblay
- Centre for Heart, Lung, and Vascular Health School of Health and Exercise Science, University of British Columbia, Kelowna, Canada.
| | - Stephen R Thom
- Department of Emergency Medicine, University of Maryland, Baltimore, USA
| | - Ming Yang
- Department of Emergency Medicine, University of Maryland, Baltimore, USA
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| |
Collapse
|
38
|
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: 49] [Impact Index Per Article: 6.1] [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.
Collapse
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
| |
Collapse
|
39
|
Abstract
We are currently in the midst of an epidemic of metabolic disorders, which may, in part, be explained by excess fructose intake. This theory is supported by epidemiological observations as well as experimental studies in animals and humans. Rising consumption of fructose has been matched with growing rates of hypertension, leading to concern from public health experts. At this stage, the mechanisms underlying fructose-induced hypertension have not been fully characterized and the bulk of our knowledge is derived from animal models. Animal studies have shown that high-fructose diets up-regulate sodium and chloride transporters, resulting in a state of salt overload that increases blood pressure. Excess fructose has also been found to activate vasoconstrictors, inactivate vasodilators, and over-stimulate the sympathetic nervous system. Further work is required to determine the relevance of these findings to humans and to establish the level at which dietary fructose increases the risk of developing hypertension
Collapse
|
40
|
Atkinson CL, Lewis NCS, Carter HH, Thijssen DHJ, Ainslie PN, Green DJ. Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans. J Physiol 2015; 593:5145-56. [PMID: 26437709 PMCID: PMC4666994 DOI: 10.1113/jp270946] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/21/2015] [Indexed: 02/06/2023] Open
Abstract
Transient reduction in vascular function following systemic large muscle group exercise has previously been reported in humans. The mechanisms responsible are currently unknown. We hypothesised that sympathetic nervous system activation, induced by cycle ergometer exercise, would contribute to post-exercise reductions in flow-mediated dilatation (FMD). Ten healthy male subjects (28 ± 5 years) undertook two 30 min sessions of cycle exercise at 75% HR(max). Prior to exercise, individuals ingested either a placebo or an α1-adrenoreceptor blocker (prazosin; 0.05 mg kg(-1)). Central haemodynamics, brachial artery shear rate (SR) and blood flow profiles were assessed throughout each exercise bout and in response to brachial artery FMD, measured prior to, immediately after and 60 min after exercise. Cycle exercise increased both mean and antegrade SR (P < 0.001) with retrograde SR also elevated under both conditions (P < 0.001). Pre-exercise FMD was similar on both occasions, and was significantly reduced (27%) immediately following exercise in the placebo condition (t-test, P = 0.03). In contrast, FMD increased (37%) immediately following exercise in the prazosin condition (t-test, P = 0.004, interaction effect P = 0.01). Post-exercise FMD remained different between conditions after correction for baseline diameters preceding cuff deflation and also post-deflation SR. No differences in FMD or other variables were evident 60 min following recovery. Our results indicate that sympathetic vasoconstriction competes with endothelium-dependent dilator activity to determine post-exercise arterial function. These findings have implications for understanding the chronic impacts of interventions, such as exercise training, which affect both sympathetic activity and arterial shear stress.
Collapse
Affiliation(s)
- Ceri L Atkinson
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
| | - Nia C S Lewis
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Howard H Carter
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
| | - Dick H J Thijssen
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
- Radboud Institute for Health Sciences, Department of Physiology, Nijmegen, Netherlands
| | - Philip N Ainslie
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Daniel J Green
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
| |
Collapse
|
41
|
Atkinson CL, Carter HH, Naylor LH, Dawson EA, Marusic P, Hering D, Schlaich MP, Thijssen DHJ, Green DJ. Opposing effects of shear-mediated dilation and myogenic constriction on artery diameter in response to handgrip exercise in humans. J Appl Physiol (1985) 2015; 119:858-64. [PMID: 26294751 DOI: 10.1152/japplphysiol.01086.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 08/01/2015] [Indexed: 11/22/2022] Open
Abstract
While the impact of changes in blood flow and shear stress on artery function are well documented, the acute effects of increases in arterial pressure are less well described in humans. The aim of this study was to assess the effect of 30 min of elevated blood pressure, in the absence of changes in shear stress or sympathetic nervous system (SNS) activation, on conduit artery diameter. Ten healthy male subjects undertook three sessions of 30 min unilateral handgrip exercise at 5, 10, and 15% of maximal voluntary contractile (MVC) strength. Brachial artery shear rate and blood flow profiles were measured simultaneously during exercise in the active and contralateral resting arms. Bilateral brachial artery diameter was simultaneously assessed before and immediately postexercise. In a second experiment, six subjects repeated the 15% MVC condition while continuous vascular measurements were collected during muscle sympathetic nerve activity (MSNA) assessment using peroneal microneurography. We found that unilateral handgrip exercise at 5, 10, and 15% MVC strength induced stepwise elevations in blood pressure (P < 0.01, Δmean arterial pressure: 7.06 ± 2.44, 8.50 ± 2.80, and 18.35 ± 3.52 mmHg, P < 0.01). Whereas stepwise increases were evident in shear rate in the exercising arm (P < 0.001), no changes were apparent in the nonexercising limb (P = 0.42). Brachial artery diameter increased in the exercising arm (P = 0.02), but significantly decreased in the nonexercising arm (P = 0.03). At 15% MVC, changes in diameter were significantly different between arms (interaction effect: P = 0.01), whereas this level of exertion produced no significant changes in MSNA. We conclude that acute increases in transmural pressure, independent of shear rate and changes in SNS activation, reduce arterial caliber in normotensive humans in vivo. These changes in diameter were mitigated by exercise-induced elevations in shear rate in the active limb.
Collapse
Affiliation(s)
- Ceri L Atkinson
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
| | - Howard H Carter
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
| | - Louise H Naylor
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
| | - Ellen A Dawson
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom
| | - Petra Marusic
- School of Medicine and Pharmacology, The University of Western Australia, Crawley, Western Australia; and
| | - Dagmara Hering
- School of Medicine and Pharmacology, The University of Western Australia, Crawley, Western Australia; and
| | - Markus P Schlaich
- School of Medicine and Pharmacology, The University of Western Australia, Crawley, Western Australia; and
| | - Dick H J Thijssen
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom; Department of Physiology, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Daniel J Green
- School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia; Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom;
| |
Collapse
|
42
|
Iwamoto E, Katayama K, Ishida K. Exercise intensity modulates brachial artery retrograde blood flow and shear rate during leg cycling in hypoxia. Physiol Rep 2015; 3:3/6/e12423. [PMID: 26038470 PMCID: PMC4510625 DOI: 10.14814/phy2.12423] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The purpose of this study was to elucidate the effect of exercise intensity on retrograde blood flow and shear rate (SR) in an inactive limb during exercise under normoxic and hypoxic conditions. The subjects performed two maximal exercise tests on a semi-recumbent cycle ergometer to estimate peak oxygen uptake (O2peak) while breathing normoxic (inspired oxygen fraction [FIO2 = 0.21]) and hypoxic (FIO2 = 0.12 or 0.13) gas mixtures. Subjects then performed four exercise bouts at the same relative intensities (30 and 60% O2peak) for 30 min under normoxic or hypoxic conditions. Brachial artery diameter and blood velocity were simultaneously recorded, using Doppler ultrasonography. Retrograde SR was enhanced with increasing exercise intensity under both conditions at 10 min of exercise. Thereafter, retrograde blood flow and SR in normoxia returned to pre-exercise levels, with no significant differences between the two exercise intensities. In contrast, retrograde blood flow and SR in hypoxia remained significantly elevated above baseline and was significantly greater at 60% than at 30% O2peak. We conclude that differences in exercise intensity affect brachial artery retrograde blood flow and SR during prolonged exercise under hypoxic conditions.
Collapse
Affiliation(s)
- Erika Iwamoto
- School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
| |
Collapse
|
43
|
Benda NMM, Seeger JPH, van Lier DPT, Bellersen L, van Dijk APJ, Hopman MTE, Thijssen DHJ. Heart failure patients demonstrate impaired changes in brachial artery blood flow and shear rate pattern during moderate-intensity cycle exercise. Exp Physiol 2015; 100:463-74. [PMID: 25655515 DOI: 10.1113/ep085040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 01/30/2015] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the central question of this study? We explored whether heart failure (HF) patients demonstrate different exercise-induced brachial artery shear rate patterns compared with control subjects. What is the main finding and its importance? Moderate-intensity cycle exercise in HF patients is associated with an attenuated increase in brachial artery anterograde and mean shear rate and skin temperature. Differences between HF patients and control subjects cannot be explained fully by differences in workload. HF patients demonstrate a less favourable shear rate pattern during cycle exercise compared with control subjects. Repeated elevations in shear rate (SR) in conduit arteries, which occur during exercise, represent a key stimulus to improve vascular function. We explored whether heart failure (HF) patients demonstrate distinct changes in SR in response to moderate-intensity cycle exercise compared with healthy control subjects. We examined brachial artery SR during 40 min of cycle exercise at a work rate equivalent to 65% peak oxygen uptake in 14 HF patients (65 ± 7 years old, 13 men and one woman) and 14 control subjects (61 ± 5 years old, 12 men and two women). Brachial artery diameter, SR and oscillatory shear index (OSI) were assessed using ultrasound at baseline and during exercise. The HF patients demonstrated an attenuated increase in mean and anterograde brachial artery SR during exercise compared with control subjects (time × group interaction, P = 0.003 and P < 0.001, respectively). Retrograde SR increased at the onset of exercise and remained increased throughout the exercise period in both groups (time × group interaction, P = 0.11). In control subjects, the immediate increase in OSI during exercise (time, P < 0.001) was normalized after 35 min of cycling. In contrast, the increase in OSI after the onset of exercise did not normalize in HF patients (time × group interaction, P = 0.029). Subgroup analysis of five HF patients and five control subjects with comparable workload (97 ± 13 versus 90 ± 22 W, P = 0.59) confirmed the presence of distinct changes in mean SR during exercise (time × group interaction, P = 0.030). Between-group differences in anterograde/retrograde SR or OSI did not reach statistical significance (time × group interactions, P > 0.05). In conclusion, HF patients demonstrate a less favourable SR pattern during cycle exercise than control subjects, characterized by an attenuated mean and anterograde SR and by increased OSI.
Collapse
Affiliation(s)
- Nathalie M M Benda
- Department of Physiology, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
44
|
Greyling A, Schreuder THA, Landman T, Draijer R, Verheggen RJHM, Hopman MTE, Thijssen DHJ. Elevation in blood flow and shear rate prevents hyperglycemia-induced endothelial dysfunction in healthy subjects and those with type 2 diabetes. J Appl Physiol (1985) 2015; 118:579-85. [PMID: 25593286 DOI: 10.1152/japplphysiol.00936.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hyperglycemia, commonly present after a meal, causes transient impairment in endothelial function. We examined whether increases in blood flow (BF) protect against the hyperglycemia-mediated decrease in endothelial function in healthy subjects and patients with type 2 diabetes mellitus (T2DM). Ten healthy subjects and 10 age- and sex-matched patients with T2DM underwent simultaneous bilateral assessment of brachial artery endothelial function by means of flow-mediated dilation (FMD) using high-resolution echo-Doppler. FMD was examined before and 60, 120, and 150 min after a 75-g oral glucose challenge. We unilaterally manipulated BF by heating one arm between minute 30 and minute 60. Oral glucose administration caused a statistically significant, transient increase in blood glucose in both groups (P < 0.001). Forearm skin temperature, brachial artery BF, and shear rate significantly increased in the heated arm (P < 0.001), and to a greater extent compared with the nonheated arm in both groups (interaction effect P < 0.001). The glucose load caused a transient decrease in FMD% (P < 0.05), whereas heating significantly prevented the decline (interaction effect P < 0.01). Also, when correcting for changes in diameter and shear rate, we found that the hyperglycemia-induced decrease in FMD can be prevented by local heating (P < 0.05). These effects on FMD were observed in both groups. Our data indicate that nonmetabolically driven elevation in BF and shear rate can similarly prevent the hyperglycemia-induced decline in conduit artery endothelial function in healthy volunteers and in patients with type 2 diabetes. Additional research is warranted to confirm that other interventions that increase BF and shear rate equally protect the endothelium when challenged by hyperglycemia.
Collapse
Affiliation(s)
- Arno Greyling
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Unilever R&D Vlaardingen, The Netherlands; and
| | - Tim H A Schreuder
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thijs Landman
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Maria T E Hopman
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| |
Collapse
|