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Martin LS, Josset-Lamaugarny A, El Jammal T, Ducreux S, Chevalier FP, Fromy B. Aging is associated with impaired triggering of TRPV3-mediated cutaneous vasodilation: a crucial process for local heat exposure. GeroScience 2024; 46:3567-3580. [PMID: 37855862 PMCID: PMC11226586 DOI: 10.1007/s11357-023-00981-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023] Open
Abstract
Sensing temperature is vitally important to adapt our body to environmental changes. Local warm detection is required to initiate regulation of cutaneous blood flow, which is part of the peripheral thermoregulatory mechanisms, and thus avoid damage to surrounding tissues. The mechanisms mediating cutaneous vasodilation during local heat stress are impaired with aging. However, the impact of aging on the ability of the skin to detect subtle thermal changes is unknown. Among heat-activated cation channels, transient receptor potential vanilloid 3 (TRPV3) is a thermo-sensor predominantly expressed on keratinocytes and involved in local vascular thermoregulatory mechanisms of the skin in young mice. In the present study, using a murine in vivo model of local heat exposure of the skin, we showed that heat-induced vasodilation was reduced in old mice associated with reduced expression of TRPV3 channels. We also found a decrease in expression and activity of TRPV3 channel, as well as reduced TRPV3-dependent adenosine tri-phosphate release in human primary keratinocytes from old donors. This study shows that aging alters the epidermal TRPV3 channels, which might delay the detection of changes in skin temperature, thereby limiting the mechanisms triggered for local vascular thermoregulation in the old skin.
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Affiliation(s)
- Lisa S Martin
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
| | - Audrey Josset-Lamaugarny
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
| | - Thomas El Jammal
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
- Department of Internal Medicine, University Hospital Lyon Croix-Rousse, Claude Bernard University Lyon 1, Lyon, France
| | - Sylvie Ducreux
- CarMeN Laboratory, INSERM, INRA, INSA Lyon, Claude Bernard University Lyon 1, 69500, Bron, France
| | - Fabien P Chevalier
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France
| | - Bérengère Fromy
- CNRS UMR 5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), 69007, Lyon, France.
- Claude Bernard University Lyon 1, 69100, Villeurbanne, France.
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2
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Kim SH, Jang SY, Cha Y, Kim BY, Lee HJ, Kim GO. Analysis of the effects of intraoperative warming devices on surgical site infection in elective hip arthroplasty using a large nationwide database. Arch Orthop Trauma Surg 2023; 143:7237-7244. [PMID: 37500931 DOI: 10.1007/s00402-023-04917-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/21/2023] [Indexed: 07/29/2023]
Abstract
INTRODUCTION The aim of our study is to analyze the association of usage and type of warming device with the risk of surgical site infection (SSI) in patients who underwent hip arthroplasty, and to analyze the factors that increase the risk of SSI if the warming device is not used. MATERIALS AND METHODS This retrospective cross-sectional study identified subjects from data of "Evaluation of the Appropriate Use of Prophylactic Antibiotics". Included patients were defined as those who underwent elective unilateral hip hemiarthroplasty or total hip arthroplasty (THA). Patients were classified into no intraoperative warming device, forced air warming devices, and devices using conduction. Multiple logistic regression analysis was conducted to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) to assess the association between warming devices and SSI. RESULTS A total of 3945 patients met the inclusion criteria. Compared to those who received an intraoperative warming device, the odds of developing SSI were 1.9 times higher in those who did not receive intraoperative warming devices (aOR 1.9; 95% CI 1.1-3.6). The risk of SSI was 2.2 times higher with forced air warming devices compared to devices using conduction but this difference was not statistically significant (aOR 2.2; 95% CI 0.7-6.8). The risk of SSI increased in males (aOR 2.8; 95% CI 1.1-7.2), in patients under 70 years of age (aOR 4.4; 95% CI 1.6-10.4), in patients with a Charlson`s comorbidity index of 2 or higher (aOR 3.3; 95% CI 1.3-8.7), and in patients who underwent THA (aOR 3.8; 95% CI 1.7-8.3) when intraoperative warming devices were not used. CONCLUSIONS The use of intraoperative active warming devices is highly recommended to prevent SSI during elective hip arthroplasty. In particular, male patients younger than 70 years, those with a high CCI, and those undergoing THA are at significantly increased risk of SSI if intraoperative active warming devices are not used. Intraoperative warming device using conduction is likely superior to forced air warming device, but further studies are needed to confirm this.
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Affiliation(s)
- Seung Hoon Kim
- Department of Preventive Medicine, Eulji University School of Medicine, Daejeon, South Korea
| | - Suk-Yong Jang
- Department of Healthcare Management, Graduate School of Public Health, Yonsei University, Seoul, South Korea
| | - Yonghan Cha
- Department of Orthopaedic Surgery, Daejeon Eulji Medical Center, Eulji University School of Medicine, 95 Dunsan Seoro, Seo-Gu, Daejeon, 35233, South Korea.
| | - Bo-Yeon Kim
- Healthcare Review and Assessment Committee, Health Insurance Review and Assessment Service, Wonju, South Korea
| | - Hyo-Jung Lee
- Quality Assessment Department, Health Insurance Review and Assessment Service, Wonju, South Korea
| | - Gui-Ok Kim
- Quality Assessment Department, Health Insurance Review and Assessment Service, Wonju, South Korea
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3
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Wang AN, Fraser GM, McGuire JJ. Characterization of Endothelium-Dependent Relaxation in the Saphenous Artery and Its Caudal Branches in Young and Old Adult Sprague Dawley Rats. Biomolecules 2022; 12:biom12070889. [PMID: 35883445 PMCID: PMC9312764 DOI: 10.3390/biom12070889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 12/11/2022] Open
Abstract
Ageing is associated with reduced endothelium-derived nitric oxide (NO) production in the femoral artery of Sprague Dawley (SD) rats. In the current study, we examined endothelium-dependent relaxation (EDR) in the saphenous artery and its caudal branches. We used acetylcholine and the Proteinase-Activated receptor-2 (PAR2)-specific agonist (2fLIGRLO) with nitroarginine methylester (L-NAME) to assess EDR in two groups of male SD rats (age in weeks: young, 10–12; old, 27–29). Acetylcholine and 2fLIGRLO were potent NO-dependent relaxant agents in all arteries. For all arteries, EDR by acetylcholine decreased significantly in old compared to young SD rats. Interestingly, PAR2-induced EDR of proximal saphenous artery segments and caudal branches decreased significantly in old compared to young, but did not differ for the in-between middle and distal ends of the saphenous artery. L-NAME treatment increased subsequent contractions of proximal and middle segments of saphenous arteries by phenylephrine and U46619 in young, but not in old, SD rats. We conclude the SD saphenous artery and caudal branches exhibit regional characteristics that differ in response to specific EDR agonists, endothelial NO synthase inhibitor, and changes to endothelium function with increased age, which are, in part, attributed to decreased sensitivity of vascular smooth muscle to the gaseous transmitter NO.
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Affiliation(s)
- Andrea N. Wang
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada;
| | - Graham M. Fraser
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University, St. John’s, NL A1B 3V6, Canada;
| | - John J. McGuire
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada;
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada
- Correspondence:
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4
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Barros PR, Costa TJ, Akamine EH, Tostes RC. Vascular Aging in Rodent Models: Contrasting Mechanisms Driving the Female and Male Vascular Senescence. FRONTIERS IN AGING 2021; 2:727604. [PMID: 35821995 PMCID: PMC9261394 DOI: 10.3389/fragi.2021.727604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 08/25/2021] [Indexed: 12/12/2022]
Abstract
Increasing scientific interest has been directed to sex as a biological and decisive factor on several diseases. Several different mechanisms orchestrate vascular function, as well as vascular dysfunction in cardiovascular and metabolic diseases in males and females. Certain vascular sex differences are present throughout life, while others are more evident before the menopause, suggesting two important and correlated drivers: genetic and hormonal factors. With the increasing life expectancy and aging population, studies on aging-related diseases and aging-related physiological changes have steeply grown and, with them, the use of aging animal models. Mouse and rat models of aging, the most studied laboratory animals in aging research, exhibit sex differences in many systems and physiological functions, as well as sex differences in the aging process and aging-associated cardiovascular changes. In the present review, we introduce the most common aging and senescence-accelerated animal models and emphasize that sex is a biological variable that should be considered in aging studies. Sex differences in the cardiovascular system, with a focus on sex differences in aging-associated vascular alterations (endothelial dysfunction, remodeling and oxidative and inflammatory processes) in these animal models are reviewed and discussed.
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Affiliation(s)
- Paula R. Barros
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Tiago J. Costa
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Eliana H. Akamine
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
- *Correspondence: Rita C. Tostes, ; Eliana H. Akamine,
| | - Rita C. Tostes
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- *Correspondence: Rita C. Tostes, ; Eliana H. Akamine,
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Stockelman KA, Bain AR, Goulding A, DeSouza NM, Rahaman C, Maly L, Greiner JJ, Stauffer BL, DeSouza CA. Negative Influence of Insufficient Sleep on Endothelial Vasodilator and Fibrinolytic Function in Hypertensive Adults. Hypertension 2021; 78:1829-1840. [PMID: 34488434 DOI: 10.1161/hypertensionaha.121.17781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Kelly A Stockelman
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado Boulder (K.A.S., A.G., N.M.D., C.R., L.M., J.J.G., C.A.D.)
| | - Anthony R Bain
- Department of Kinesiology, University of Windsor, ON, Canada (A.R.B.)
| | - Anabel Goulding
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado Boulder (K.A.S., A.G., N.M.D., C.R., L.M., J.J.G., C.A.D.)
| | - Noah M DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado Boulder (K.A.S., A.G., N.M.D., C.R., L.M., J.J.G., C.A.D.)
| | - Clay Rahaman
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado Boulder (K.A.S., A.G., N.M.D., C.R., L.M., J.J.G., C.A.D.)
| | - Lukas Maly
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado Boulder (K.A.S., A.G., N.M.D., C.R., L.M., J.J.G., C.A.D.)
| | - Jared J Greiner
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado Boulder (K.A.S., A.G., N.M.D., C.R., L.M., J.J.G., C.A.D.)
| | - Brian L Stauffer
- Department of Medicine, Anschutz Medical Center, University of Colorado Denver (B.L.S., C.A.D.).,Department of Medicine, Division of Cardiology, Denver Health Medical Center, CO (B.L.S.)
| | - Christopher A DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado Boulder (K.A.S., A.G., N.M.D., C.R., L.M., J.J.G., C.A.D.).,Department of Medicine, Anschutz Medical Center, University of Colorado Denver (B.L.S., C.A.D.)
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6
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Cho AR, Lee HJ, Kim HJ, Do W, Jeon S, Baek SH, Kim ES, Kwon JY, Kim HK. Microvascular Reactivity Measured by Dynamic Near-infrared Spectroscopy Following Induction of General Anesthesia in Healthy Patients: Observation of Age-related Change. Int J Med Sci 2021; 18:1096-1103. [PMID: 33526968 PMCID: PMC7847632 DOI: 10.7150/ijms.52433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 12/18/2020] [Indexed: 01/31/2023] Open
Abstract
Background: The purpose of this study was to investigate the effect of general anesthesia on microvascular reactivity and tissue oxygen saturation (StO2) using near-infrared spectroscopy in conjunction with vascular occlusion tests (VOT). Age-related changes of microvascular reactivity, that is, the capacity of capillary recruitment, were examined. Methods: This prospective observational study was performed on 60 patients without comorbidities who underwent elective surgery under general anesthesia. Baseline StO2 on thenar eminence, hemodynamics, and laboratory profile were monitored before (T0) and 30 min after general anesthesia (T1). During VOT, occlusion slope representing oxygen consumption of muscle and recovery slope representing microvascular reactivity were also collected at T0 and T1. Results: Baseline StO2 and minimum / maximum StO2 during VOT increased under general anesthesia. Occlusion slope decreased while the recovery slope increased under general anesthesia. To observe aging effect, Receiver operating characteristic analysis was performed and age less than 65 years old showed a fair performance in predicting the increase of microvascular reactivity after the induction of anesthesia (AUC 0.733, 95% CI 0.594-0.845, P= 0.003). For age-related analyses, 27 patients of younger group (< 65 years) and 26 patients of older group (≥ 65 years) were divided. Recovery slope significantly increased under general anesthesia in younger group (2.44 [1.91-2.81] % ∙ sec-1 at T0 and 3.59 [2.58-3.51] % ∙ sec-1 at T1, P <0.001), but not in older group (2.61 [2.21-3.20] % ∙ sec-1 at T0, 2.63 [1.90-3.60] % ∙ sec-1 at T1, P = 0.949). Conclusions: General anesthesia could improve StO2 through increase of microvascular reactivity and decrease of tissue metabolism. However, microvascular reactivity to capillary recruitment under general anesthesia significantly improves in younger patients, not in older patients.
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Affiliation(s)
- Ah-Reum Cho
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Anesthesia and Pain Medicine, Pusan National University, School of Medicine, Yangsan, Republic of Korea
| | - Hyeon-Jeong Lee
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Anesthesia and Pain Medicine, Pusan National University, School of Medicine, Yangsan, Republic of Korea
| | - Hyae-Jin Kim
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Wangseok Do
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Soeun Jeon
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Seung-Hoon Baek
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Anesthesia and Pain Medicine, Pusan National University, School of Medicine, Yangsan, Republic of Korea
| | - Eun-Soo Kim
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Anesthesia and Pain Medicine, Pusan National University, School of Medicine, Yangsan, Republic of Korea
| | - Jae-Young Kwon
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Anesthesia and Pain Medicine, Pusan National University, School of Medicine, Yangsan, Republic of Korea
| | - Hae-Kyu Kim
- Department of Anesthesia and Pain Medicine, Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.,Department of Anesthesia and Pain Medicine, Pusan National University, School of Medicine, Yangsan, Republic of Korea
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7
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Hearon CM, Richards JC, Racine ML, Luckasen GJ, Larson DG, Dinenno FA. Augmentation of endothelium-dependent vasodilatory signalling improves functional sympatholysis in contracting muscle of older adults. J Physiol 2020; 598:2323-2336. [PMID: 32306393 DOI: 10.1113/jp279462] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/14/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction (functional sympatholysis) is critical for maintaining blood flow during exercise-mediated sympathoexcitation. Functional sympatholysis and endothelial function are impaired with ageing, resulting in compromised blood flow and oxygen delivery to contracting skeletal muscle during exercise. In the present study, intra-arterial infusion of ACh or ATP to augment endothelium-dependent signalling during exercise attenuated α1 -adrenergic vasoconstriction in the contracting muscle of older adults. The vascular signalling mechanisms capable of functional sympatholysis are preserved in healthy ageing, and thus the age-related impairment in functional sympatholysis probably results from the loss of a functional signal (e.g. plasma [ATP]) as opposed to an intrinsic endothelial dysfunction. ABSTRACT The ability of contracting skeletal muscle to attenuate sympathetic α-adrenergic vasoconstriction ('functional sympatholysis') is impaired with age. In young adults, increasing endothelium-dependent vasodilatory signalling during mild exercise augments sympatholysis. In the present study, we tested the hypothesis that increasing endothelium-dependent signalling during exercise in older adults can improve sympatholysis. In 16 older individuals (Protocol 1, n = 8; Protocol 2, n = 8), we measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to local intra-arterial infusion of phenylephrine (PE; α1 -agonist) during (i) infusion of an endothelium-dependent vasodilator alone (Protocol 1: ACh or Protocol 2: low dose ATP); (ii) mild handgrip exercise (5% maximum voluntary contraction; MVC); (iii) moderate handgrip exercise (15% MVC); and (iv) mild or moderate handgrip exercise + infusion of ACh or ATP to augment endothelium-dependent signalling. PE caused robust vasoconstriction in resting skeletal muscle during control vasodilator infusions (ΔFVC: ACh: -31 ± 3 and ATP: -30 ± 4%). PE-mediated vasoconstriction was not attenuated by mild or moderate intensity exercise (ΔFVC: 5% MVC: -30 ± 9; 15% MVC: -33 ± 8%; P > 0.05 vs. control ACh and ATP), indicative of impaired sympatholysis, and ACh or ATP infusion during mild exercise did not impact this response. However, augmentation of endothelium-dependent signalling via infusion of ACh or ATP during moderate intensity exercise attenuated PE-mediated vasoconstriction (ΔFVC: -13 ± 1 and -19 ± 5%, respectively; P < 0.05 vs. all conditions). Our findings demonstrate that, given a sufficient stimulus, endothelium-dependent sympatholysis remains intact in older adults. Strategies aimed at activating such pathways represent a viable approach for improving sympatholysis and thus tissue blood flow and oxygen delivery in older adults.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Mathew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, USA
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8
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Nakamura A, Kajitani S, Sato K, Kanazawa M, Kondo M, Endo H, Nozaki E. Decline of popliteal artery flow-mediated dilation with aging and possible involvement of asymmetric dimethylarginine in healthy men. J Med Ultrason (2001) 2019; 46:503-511. [PMID: 31011935 PMCID: PMC6765476 DOI: 10.1007/s10396-019-00946-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/05/2019] [Indexed: 12/17/2022]
Abstract
Purpose We examined the influences of age and gender on flow-mediated endothelial function and the involvement of the competitive inhibition of l-arginine in endothelial function. Methods We measured brachial and popliteal flow-mediated vasodilation (FMD) responses, nitrate/nitrite (NOx) concentrations, and plasma levels of asymmetric dimethylarginine (ADMA) in four healthy, nonsmoking groups: young men (mean 26 ± 2 years, n = 17), middle-aged men (mean 50 ± 3 years, n = 19), young women (mean 27 ± 2 years, n = 16), and middle-aged women (mean 51 ± 2 years, n = 18). Results In young men, we found no significant differences between brachial and popliteal artery FMDs (10.6 ± 1.5 vs 8.7 ± 1.6%, p = 0.06). However, the popliteal artery FMD was significantly lower than the brachial artery FMD in middle-aged men (11.4 ± 1.5 vs 6.4 ± 1.0%, p < 0.001). In women, we found no significant differences between brachial and popliteal artery FMDs in young and middle-aged individuals (young, p = 0.17; middle-aged, p = 0.08). Popliteal artery FMD correlated with plasma NOx and ADMA levels as well as with the NOx/ADMA ratio in men but not in women (r = 0.485, − 0.544, and 0.672, respectively). Conclusion We concluded that a decrease in flow-mediated endothelial function in arteries of the lower extremities was evident in healthy middle-aged men, but not in middle-aged women. The competitive inhibition of l-arginine may contribute to this decrease in men.
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Affiliation(s)
- Akihiro Nakamura
- Department of Cardiology, Iwate Prefectural Central Hospital, 1-4-1 Ueda, Morioka, 020-0066, Japan.
| | - Shoko Kajitani
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kenjiro Sato
- Department of Cardiology, Iwate Prefectural Central Hospital, 1-4-1 Ueda, Morioka, 020-0066, Japan
| | - Masanori Kanazawa
- Department of Cardiology, Iwate Prefectural Central Hospital, 1-4-1 Ueda, Morioka, 020-0066, Japan
| | - Masateru Kondo
- Department of Cardiology, Iwate Prefectural Central Hospital, 1-4-1 Ueda, Morioka, 020-0066, Japan
| | - Hideaki Endo
- Department of Cardiology, Iwate Prefectural Central Hospital, 1-4-1 Ueda, Morioka, 020-0066, Japan
| | - Eiji Nozaki
- Department of Cardiology, Iwate Prefectural Central Hospital, 1-4-1 Ueda, Morioka, 020-0066, Japan
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9
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Richards JC, Crecelius AR, Larson DG, Luckasen GJ, Dinenno FA. Impaired peripheral vasodilation during graded systemic hypoxia in healthy older adults: role of the sympathoadrenal system. Am J Physiol Heart Circ Physiol 2017; 312:H832-H841. [PMID: 28159810 DOI: 10.1152/ajpheart.00794.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 02/01/2023]
Abstract
Systemic hypoxia is a physiological and pathophysiological stress that activates the sympathoadrenal system and, in young adults, leads to peripheral vasodilation. We tested the hypothesis that peripheral vasodilation to graded systemic hypoxia is impaired in older healthy adults and that this age-associated impairment is due to attenuated β-adrenergic mediated vasodilation and elevated α-adrenergic vasoconstriction. Forearm blood flow was measured (Doppler ultrasound), and vascular conductance (FVC) was calculated in 12 young (24 ± 1 yr) and 10 older (63 ± 2 yr) adults to determine the local dilatory responses to graded hypoxia (90, 85, and 80% O2 saturations) in control conditions, following local intra-arterial blockade of β-receptors (propranolol), and combined blockade of α- and β-receptors (phentolamine + propranolol). Under control conditions, older adults exhibited impaired vasodilation to hypoxia compared with young participants at all levels of hypoxia (peak ΔFVC at 80% [Formula: see text] = 4 ± 6 vs. 35 ± 8%; P < 0.01). During β-blockade, older adults actively constricted at 85 and 80% [Formula: see text] (peak ΔFVC at 80% [Formula: see text] = -13 ± 6%; P < 0.05 vs. control), whereas the response in the young was not significantly impacted (peak ΔFVC = 28 ± 8%). Combined α- and β-blockade increased the dilatory response to hypoxia in young adults; however, older adults failed to significantly vasodilate (peak ΔFVC at 80% [Formula: see text]= 12 ± 11% vs. 58 ± 11%; P < 0.05). Our findings indicate that peripheral vasodilation to graded systemic hypoxia is significantly impaired in older adults, which cannot be fully explained by altered sympathoadrenal control of vascular tone. Thus, the impairment in hypoxic vasodilation is likely due to attenuated local vasodilatory and/or augmented vasoconstrictor signaling with age.NEW & NOTEWORTHY We found that the lack of peripheral vasodilation during graded systemic hypoxia with aging is not mediated by the sympathoadrenal system, strongly implicating local vascular control mechanisms in this impairment. Understanding these mechanisms may lead to therapeutic advances for improving tissue blood flow and oxygen delivery in aging and disease.
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Affiliation(s)
- Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado; and
| | - Anne R Crecelius
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado; and
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, Colorado
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, Colorado
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado; and
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10
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Hearon CM, Kirby BS, Luckasen GJ, Larson DG, Dinenno FA. Endothelium-dependent vasodilatory signalling modulates α 1 -adrenergic vasoconstriction in contracting skeletal muscle of humans. J Physiol 2016; 594:7435-7453. [PMID: 27561916 DOI: 10.1113/jp272829] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/17/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS 'Functional sympatholysis' describes the ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction, and is critical to ensure proper blood flow and oxygen delivery to metabolically active skeletal muscle. The signalling mechanism responsible for sympatholysis in healthy humans is unknown. Evidence from animal models has identified endothelium-derived hyperpolarization (EDH) as a potential mechanism capable of attenuating sympathetic vasoconstriction. In this study, increasing endothelium-dependent signalling during exercise significantly enhanced the ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction in humans. This is the first study in humans to identify endothelium-dependent regulation of sympathetic vasoconstriction in contracting skeletal muscle, and specifically supports a role for EDH-like vasodilatory signalling. Impaired functional sympatholysis is a common feature of cardiovascular ageing, hypertension and heart failure, and thus identifying fundamental mechanisms responsible for sympatholysis is clinically relevant. ABSTRACT Stimulation of α-adrenoceptors elicits vasoconstriction in resting skeletal muscle that is blunted during exercise in an intensity-dependent manner. In humans, the underlying mechanisms remain unclear. We tested the hypothesis that stimulating endothelium-dependent vasodilatory signalling will enhance the ability of contracting skeletal muscle to blunt α1 -adrenergic vasoconstriction. Changes in forearm vascular conductance (FVC; Doppler ultrasound, brachial intra-arterial pressure via catheter) to local intra-arterial infusion of phenylephrine (PE; α1 -adrenoceptor agonist) were calculated during (1) infusion of the endothelium-dependent vasodilators acetylcholine (ACh) and adenosine triphosphate (ATP), the endothelium-independent vasodilator (sodium nitroprusside, SNP), or potassium chloride (KCl) at rest; (2) mild or moderate intensity handgrip exercise; and (3) combined mild exercise + ACh, ATP, SNP, or KCl infusions in healthy adults. Robust vasoconstriction to PE was observed during vasodilator infusion alone and mild exercise, and this was blunted during moderate intensity exercise (ΔFVC: -34 ± 4 and -34 ± 3 vs. -13 ± 2%, respectively, P < 0.05). Infusion of ACh or ATP during mild exercise significantly attenuated PE vasoconstriction similar to levels observed during moderate exercise (ACh: -3 ± 4; ATP: -18 ± 4%). In contrast, infusion of SNP or KCl during mild exercise did not attenuate PE-mediated vasoconstriction (-32 ± 5 and -46 ± 3%). To further study the role of endothelium-dependent hyperpolarization (EDH), ACh trials were repeated with combined nitric oxide synthase and cyclooxygenase inhibition. Here, PE-mediated vasoconstriction was blunted at rest (blockade: -20 ± 5 vs. CONTROL -31 ± 3% vs.; P < 0.05) and remained blunted during exercise (blockade: -15 ± 5 vs. CONTROL -14 ± 5%). We conclude that stimulation of EDH-like vasodilatation can blunt α1 -adrenergic vasoconstriction in contracting skeletal muscle of humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Brett S Kirby
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, 80538, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, 80538, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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11
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Fujii N, Notley SR, Minson CT, Kenny GP. Administration of prostacyclin modulates cutaneous blood flow but not sweating in young and older males: roles for nitric oxide and calcium-activated potassium channels. J Physiol 2016; 594:6419-6429. [PMID: 27511105 DOI: 10.1113/jp273174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/09/2016] [Indexed: 01/19/2023] Open
Abstract
KEY POINTS In young adults, cyclooxygenase (COX) contributes to the heat loss responses of cutaneous vasodilatation and sweating, and this may be mediated by prostacyclin-induced activation of nitric oxide synthase (NOS) and calcium-activated potassium (KCa) channels. This prostacyclin-induced response may be diminished in older relative to young adults because ageing is known to attenuate COX-dependent heat loss responses. We observed that, although prostacyclin does not mediate sweating in young and older males, it does modulate cutaneous vasodilatation, although the magnitude of increase is similar between groups. We also found that, although NOS and KCa channels contribute to prostacyclin-induced cutaneous vasodilatation in young males, these contributions are diminished in older males. Our findings provide new insight into the mechanisms governing heat loss responses and suggest that the age-related diminished COX-dependent heat loss responses reported in previous studies may be a result of the reduced COX-derived production of prostanoids (e.g., prostacyclin) rather than the decreased sensitivity of prostanoid receptors. ABSTRACT Cyclooxygenase (COX) contributes to the regulation of cutaneous vasodilatation and sweating; however, the mechanism(s) underpinning this response remain unresolved. We hypothesized that prostacyclin (a COX-derived product) may directly mediate cutaneous vasodilatation and sweating through nitric oxide synthase (NOS) and calcium-activated potassium (KCa) channels in young adults. However, these responses would be diminished in older adults because ageing attenuates COX-dependent cutaneous vasodilatation and sweating. In young (25 ± 4 years) and older (60 ± 6 years) males (nine per group), cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal forearm skin sites: (i) control; (ii) 10 mm NG -nitro-l-arginine (l-NNA), a non-specific NOS inhibitor; (iii) 50 mm tetraethylammonium (TEA), a non-specific KCa channel blocker; and (iv) 10 mm l-NNA + 50 mm TEA. All four sites were coadministered with prostacyclin in an incremental manner (0.04, 0.4, 4, 40 and 400 μm each for 25 min). Prostacyclin-induced increases in CVC were similar between groups (all concentrations, P > 0.05). l-NNA and TEA, as well as their combination, lowered CVC in young males at all prostacyclin concentrations (P ≤ 0.05), with the exception of l-NNA at 0.04 μm (P > 0.05). In older males, CVC during prostacyclin administration was not influenced by l-NNA (all concentrations), TEA (4-400 μm) or their combination (400 μm) (P > 0.05). No effect on sweat rate was observed in either group (all concentrations, P > 0.05). We conclude that, although prostacyclin does not mediate sweating, it modulates cutaneous vasodilatation to a similar extent in young and older males. Furthermore, although NOS and KCa channels contribute to the prostacyclin-induced cutaneous vasodilatation in young males, these contributions are diminished in older males.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Sean R Notley
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, Australia
| | | | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada.
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12
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Abstract
AIM Advanced age is associated with vascular endothelial dysfunction, characterized by reductions in the endothelium-dependent vasodilation of the conduit and resistance arteries, in part, from decreased nitric oxide bioavailability. Although vascular smooth muscle function (SMF), assessed by responsiveness to an exogenous nitric oxide donor, is typically reported to be intact, many of these studies are limited by a small sample size. Therefore, the purpose of this meta-analysis is to systematically review and determine whether vascular SMF is different between older versus young healthy individuals. DESIGN We conducted a systematic search of MEDLINE, Cochrane and Scopus, since their inceptions until January 2014, for articles evaluating SMF in the brachial artery and/or resistance arteries (BASMF and RASMF, respectively), as assessed by the endothelium-independent vasodilator response to exogenous nitric oxide donors in older (≥60 years) and young (<30 years) groups of healthy individuals. Meta-analyses were performed to compare the mean difference in BASMF and the standardized mean difference in RASMF between older and young groups. Subgroup analyses were performed to identify sources of heterogeneity. RESULTS Fifteen studies assessing BASMF and 20 studies assessing RASMF were included, comprising 550 older and 516 young healthy individuals. After data pooling, BASMF and RASMF were lower in older compared with the young groups (mean difference = -1.89%, P = 0.04; standardized mean difference = -0.46, P = 0.0008, respectively). Significant heterogeneity was observed in the BASMF (I2 = 74%, P < 0.00001) and the RASMF (I2 = 57%, P = 0.0008) meta-analyses. Subgroup analyses revealed that studies with (predominantly) men showed similar SMF responses between the older and the young groups. CONCLUSION On the basis of the current published studies, vascular SMF is reduced in conduit and resistance arteries of otherwise healthy older individuals, particularly in women.
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13
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Phillips BE, Atherton PJ, Varadhan K, Limb MC, Williams JP, Smith K. Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men. Appl Physiol Nutr Metab 2016; 41:548-56. [PMID: 27120341 DOI: 10.1139/apnm-2015-0543] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The anabolic effects of nutrition on skeletal muscle may depend on adequate skeletal muscle perfusion, which is impaired in older people. Cocoa flavanols have been shown to improve flow-mediated dilation, an established measure of endothelial function. However, their effect on muscle microvascular blood flow is currently unknown. Therefore, the objective of this study was to explore links between the consumption of cocoa flavanols, muscle microvascular blood flow, and muscle protein synthesis (MPS) in response to nutrition in older men. To achieve this objective, leg blood flow (LBF), muscle microvascular blood volume (MBV), and MPS were measured under postabsorptive and postprandial (intravenous Glamin (Fresenius Kabi, Germany), dextrose to sustain glucose ∼7.5 mmol·L(-1)) conditions in 20 older men. Ten of these men were studied with no cocoa flavanol intervention and a further 10 were studied with the addition of 350 mg of cocoa flavanols at the same time that nutrition began. Leg (femoral artery) blood flow was measured by Doppler ultrasound, muscle MBV by contrast-enhanced ultrasound using Definity (Lantheus Medical Imaging, Mass., USA) perflutren contrast agent and MPS using [1, 2-(13)C2]leucine tracer techniques. Our results show that although older individuals do not show an increase in LBF or MBV in response to feeding, these absent responses are apparent when cocoa flavanols are given acutely with nutrition. However, this restoration in vascular responsiveness is not associated with improved MPS responses to nutrition. We conclude that acute cocoa flavanol supplementation improves muscle macro- and microvascular responses to nutrition, independently of modifying muscle protein anabolism.
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Affiliation(s)
- Bethan E Phillips
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Philip J Atherton
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Krishna Varadhan
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Marie C Limb
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - John P Williams
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Kenneth Smith
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK.,School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
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14
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Eisenach JH, Gullixson LR, Allen AR, Kost SL, Nicholson WT. Cyclo-oxygenase-2 inhibition and endothelium-dependent vasodilation in younger vs. older healthy adults. Br J Clin Pharmacol 2015; 78:815-23. [PMID: 24698105 DOI: 10.1111/bcp.12397] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 03/29/2014] [Indexed: 12/01/2022] Open
Abstract
AIM A major feature of endothelial dysfunction is reduced endothelium-dependent vasodilation, which in ageing may be due to decreased production of endothelial prostacyclin, or nitric oxide (NO), or both. METHOD We tested this hypothesis in 12 younger (age 18-38 years, six women) and 12 older healthy adults (age 55-73 years, six post-menopausal women). Endothelium-dependent vasodilation was assessed by the forearm vascular conductance (FVC) response to intra-arterial acetylcholine (ACh) (0.5, 1.0, 2.0, 4.0 μg dl(-1) forearm tissue min(-1) ) before and 90 min after inhibition of the enzyme cyclo-oxygenase-2 (COX-2) with oral celecoxib (400 mg), followed by the addition of endothelial NO synthase inhibition with intra-arterial N(G) -monomethyl-l arginine acetate (L-NMMA). RESULTS Ageing was associated with a significantly reduced FVC response to ACh (P = 0.009, age-by-dose interaction; highest dose FVC ± SEM in ageing: 11.2 ± 1.4 vs. younger: 17.7 ± 2.4 units, P = 0.02). Celecoxib did not reduce resting FVC or the responses to ACh in any group. L-NMMA significantly reduced resting FVC and the responses to ACh in all groups, and absolute FVC values following L-NMMA were similar between groups. CONCLUSION In healthy normotensive younger and older adults, there is minimal contribution of prostacyclin to ACh-mediated vasodilation, yet the NO component of vasodilation is reduced with ageing. In the clinical context, these findings suggest that acute administration of medications that inhibit prostacyclin (i.e. COX-2 inhibitors) evoke modest vascular consequences in healthy persons. Additional studies are necessary to test whether chronic use of COX-2 medications reduces endothelium dependent vasodilation in older persons with or without cardiovascular risk factors.
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Affiliation(s)
- John H Eisenach
- Departments of Anesthesiology, Physiology and Biomedical Engineering, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905
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15
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Bentov I, Reed MJ. The effect of aging on the cutaneous microvasculature. Microvasc Res 2015; 100:25-31. [PMID: 25917013 PMCID: PMC4461519 DOI: 10.1016/j.mvr.2015.04.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/27/2015] [Accepted: 04/17/2015] [Indexed: 01/12/2023]
Abstract
Aging is associated with a progressive loss of function in all organs. Under normal conditions the physiologic compensation for age-related deficits is sufficient, but during times of stress the limitations of this reserve become evident. Explanations for this reduction in reserve include the changes in the microcirculation that occur during the normal aging process. The microcirculation is defined as the blood flow through arterioles, capillaries and venules, which are the smallest vessels in the vasculature and are embedded within organs and tissues. Optimal strategies to maintain the microvasculature following surgery and other stressors must use multifactorial approaches. Using skin as the model organ, we will review the anatomical and functional changes in the microcirculation with aging, and some of the available clinical strategies to potentially mitigate the effect of these changes on important clinical outcomes.
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Affiliation(s)
- Itay Bentov
- Department of Anesthesiology and Pain Medicine, Harborview Medical Center, University of Washington, Seattle, USA.
| | - May J Reed
- Division of Gerontology and Geriatric Medicine, Department of Medicine, Harborview Medical Center, University of Washington, Seattle, USA
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16
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Casey DP, Ranadive SM, Joyner MJ. Aging is associated with altered vasodilator kinetics in dynamically contracting muscle: role of nitric oxide. J Appl Physiol (1985) 2015; 119:232-41. [PMID: 26023230 DOI: 10.1152/japplphysiol.00787.2014] [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] [Received: 08/29/2014] [Accepted: 05/26/2015] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that aging would be associated with slowed vasodilator kinetics in contracting muscle in part due to a reduced nitric oxide (NO) bioavailability. Young (n = 10; 24 ± 2 yr) and older (n = 10; 67 ± 2 yr) adults performed rhythmic forearm exercise (4 min each) at 10, 20, and 30% of max during saline infusion (control) and NO synthase (NOS) inhibition. Brachial artery diameter and velocities were measured using Doppler ultrasound. Forearm vascular conductance (FVC) was calculated for each duty cycle (1 s contraction/2 s relaxation) from forearm blood flow (FBF; ml/min) and blood pressure (mmHg) and fit with a monoexponential model. The main parameters derived from the model were the amplitude of the FBF and FVC response and the number of duty cycles for FBF and FVC to change 63% of the steady-state amplitude (τFBF and τFVC). Under control conditions 1) the amplitude of the FVC response at 30% maximal voluntary contraction (MVC) was lower in older compared with young adults (319 ± 33 vs. 462 ± 52 ml·min(-1)·100 mmHg(-1); P < 0.05) and 2) τFVC was slower in older (10 ± 1, 13 ± 1, and 15 ± 1 duty cycles) compared with young (6 ± 1, 9 ± 1, and 11 ± 1 duty cycles) adults at all intensities (P < 0.05). In young adults, NOS inhibition blunted the amplitude of the FVC response at 30% MVC and prolonged the τFVC at all intensities (10 ± 2, 12 ± 1, and 16 ± 2 duty cycles; P < 0.05), whereas it did not change in older adults. Our data indicate that the blood flow and vasodilator kinetics in exercising muscle are altered with aging possibly due to blunted NO signaling.
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Affiliation(s)
- Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
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17
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Phillips BE, Atherton PJ, Varadhan K, Limb MC, Wilkinson DJ, Sjøberg KA, Smith K, Williams JP. The effects of resistance exercise training on macro- and micro-circulatory responses to feeding and skeletal muscle protein anabolism in older men. J Physiol 2015; 593:2721-34. [PMID: 25867865 DOI: 10.1113/jp270343] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/07/2015] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Increases in limb blood flow in response to nutrition are reduced in older age. Muscle microvascular blood flow (MBF) in response to nutrition is also reduced with advancing age and this may contribute to age-related 'anabolic resistance'. Resistance exercise training (RET) can rejuvenate limb blood flow responses to nutrition in older individuals. We report here that 20 weeks of RET also restores muscle MBF in older individuals. Restoration of MBF does not, however, enhance muscle anabolic responses to nutrition. ABSTRACT The anabolic effects of dietary protein on skeletal muscle depend on adequate skeletal muscle perfusion, which is impaired in older people. This study explores fed state muscle microvascular blood flow, protein metabolism and exercise training status in older men. We measured leg blood flow (LBF), muscle microvascular blood volume (MBV) and muscle protein turnover under post-absorptive and fed state (i.v. Glamin to double amino acids, dextrose to sustain glucose ∼7-7.5 mmol l(-1) ) conditions in two groups: 10 untrained men (72.3 ± 1.4 years; body mass index (BMI) 26.5 ± 1.15 kg m(2) ) and 10 men who had undertaken 20 weeks of fully supervised, whole-body resistance exercise training (RET) (72.8 ± 1.4 years; BMI 26.3 ± 1.2 kg m(2) ). We measured LBF by Doppler ultrasound and muscle MBV by contrast-enhanced ultrasound. Muscle protein synthesis (MPS) was measured using [1, 2-(13) C2 ] leucine with breakdown (MPB) and net protein balance (NPB) by ring-[D5 ] phenylalanine tracers. Plasma insulin was measured via ELISA and indices of anabolic signalling (e.g. Akt/mTORC1) by immunoblotting from muscle biopsies. Whereas older untrained men did not exhibit fed-state increases in LBF or MBV, the RET group exhibited increases in both LBF and MBV. Despite our hypothesis that enhanced fed-state circulatory responses would improve anabolic responses to nutrition, fed-state increases in MPS (∼50-75%; P < 0.001) were identical in both groups. Finally, whereas only the RET group exhibited fed-state suppression of MPB (∼-38%; P < 0.05), positive NPB achieved was similar in both groups. We conclude that RET enhances fed-state LBF and MBV and restores nutrient-dependent attenuation of MPB without robustly enhancing MPS or NPB.
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Affiliation(s)
- Bethan E Phillips
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Philip J Atherton
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Krishna Varadhan
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Marie C Limb
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Daniel J Wilkinson
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - Kim A Sjøberg
- University of Copenhagen, Department of Exercise and Sport Sciences, Copenhagen, Denmark
| | - Kenneth Smith
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
| | - John P Williams
- University of Nottingham, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Derby, UK
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18
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Ross AJ, Gao Z, Pollock JP, Leuenberger UA, Sinoway LI, Muller MD. β-Adrenergic receptor blockade impairs coronary exercise hyperemia in young men but not older men. Am J Physiol Heart Circ Physiol 2014; 307:H1497-503. [PMID: 25239806 DOI: 10.1152/ajpheart.00584.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Patients with coronary artery disease have attenuated coronary vasodilator responses to physiological stress, which is partially attributed to a β-adrenergic receptor (β-AR)-mediated mechanisms. Whether β-ARs contribute to impaired coronary vasodilation seen with healthy aging is unknown. The purpose of this study was to investigate the role of β-ARs in coronary exercise hyperemia in healthy humans. Six young men (26 ± 1 yr) and seven older men (67 ± 4 yr) performed isometric handgrip exercise at 30% maximal voluntary contraction for 2 min after receiving intravenous propranolol, a β-AR antagonist, and no treatment. Isoproterenol, a β-AR agonist, was infused to confirm the β-AR blockade. Blood pressure and heart rate were monitored continuously, and coronary blood flow velocity (CBV, left anterior descending artery) was measured by transthoracic Doppler echocardiography. Older men had an attenuated ΔCBV to isometric exercise (3.8 ± 1.3 vs. 9.7 ± 2.1 cm/s, P = 0.02) compared with young men. Propranolol decreased the ΔCBV at peak handgrip exercise in young men (9.7 ± 2.1 vs. 2.7 ± 0.9 cm/s, P = 0.008). However, propranolol had no effect on ΔCBV in older men (3.8 ± 1.3 vs. 4.2 ± 1.9 cm/s, P = 0.9). Older men also had attenuated coronary hyperemia to low-dose isoproterenol. These data indicate that β-AR control of coronary blood flow is impaired in healthy older men.
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Affiliation(s)
- Amanda J Ross
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Zhaohui Gao
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Jonathan P Pollock
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Urs A Leuenberger
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Matthew D Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
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19
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Hart EC, Wallin BG, Barnes JN, Joyner MJ, Charkoudian N. Sympathetic nerve activity and peripheral vasodilator capacity in young and older men. Am J Physiol Heart Circ Physiol 2014; 306:H904-9. [PMID: 24414063 DOI: 10.1152/ajpheart.00181.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Interindividual variability in sympathetic nerve activity (SNA) has provided insight into integrative mechanisms contributing to blood pressure (BP) regulation in humans. In young people, the influence of high SNA on BP is balanced by lower cardiac output and less adrenergic vasoconstrictor responsiveness. Older people have higher SNA and higher BP. We hypothesized that SNA has a restraining effect on peripheral vasodilator responsiveness in young and older men, such that individuals with higher tonic SNA would show less forearm vasodilatation to exogenous vasodilators. We measured muscle SNA (MSNA; microneurography) and forearm vasodilator responses to intra-arterial infusions of acetylcholine (ACh; endothelium dependent) and sodium nitroprusside (SNP; endothelium independent) in 13 young (age; 27 ± 1 yr) and 16 older (61 ± 2 yr) men. Forearm vascular conductance (FVC) responses to ACh were lower in the older men at the two highest doses (2 and 4 μg·100 ml(-1)·min(-1); Δ395 ± 81 vs. 592 ± 87% and 412 ± 87 vs. 616 ± 132%, P < 0.05), and MSNA was higher (64 ± 4 vs. 41 ± 2 bursts/100 hb; P < 0.05). There was no difference in the FVC response to SNP between young and older men (P > 0.05). In young men, there was an inverse relationship between resting MSNA and FVC responses (%change) to both ACh and SNP (r = -0.83 and r = -0.83, respectively; P < 0.05). In older men, however, this relationship was not observed. Tonic SNA may act to restrain vasodilator responses in young men, whereas in older men a lack of such restraint may be protective against the pressor effects of higher SNA.
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Affiliation(s)
- Emma C Hart
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
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20
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Casey DP, Walker BG, Ranadive SM, Taylor JL, Joyner MJ. Contribution of nitric oxide in the contraction-induced rapid vasodilation in young and older adults. J Appl Physiol (1985) 2013; 115:446-55. [PMID: 23788575 DOI: 10.1152/japplphysiol.00446.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that reduced nitric oxide (NO) bioavailability contributes to the attenuated peak and total vasodilation following single-muscle contractions in older adults. Young (n = 10; 24 ± 2 yr) and older (n = 10; 67 ± 2 yr) adults performed single forearm contractions at 10, 20, and 40% of maximum during saline infusion (control) and NO synthase (NOS) inhibition via N(G)-monomethyl-l-arginine. Brachial artery diameters and velocities were measured using Doppler ultrasound and forearm vascular conductance (FVC; in ml·min(-1)·100 mmHg(-1)) was calculated from blood flow (ml/min) and blood pressure (mmHg). Peak and total vasodilator responses [change (Δ) in FVC from baseline] were attenuated in older adults at all intensities (P < 0.05). NOS inhibition reduced the peak ΔFVC at 10% (88 ± 12 vs. 52 ± 9 ml·min(-1)·100 mmHg(-1)), 20% (125 ± 13 vs. 83 ± 13 ml·min(-1)·100 mmHg(-1)), and 40% (207 ± 26 vs. 133 ± 20 ml·min(-1)·100 mmHg(-1)) in young subjects, (P < 0.05 for all) and in older adults at 10% (59 ± 5 vs. 47 ± 7 ml·min(-1)·100 mmHg(-1), P < 0.05) and 20% (88 ± 9 vs. 68 ± 9 ml·min(-1)·100 mmHg(-1), P < 0.05), but not 40% (128 ± 12 vs. 105 ± 11 ml·min(-1)·100 mmHg(-1), P = 0.11). The relative (%) reduction in peak ΔFVC due to NOS inhibition was greater in young vs. older adults at 20% (-36 ± 5 vs. -23 ± 5%, P < 0.05) and 40% (-35 ± 6 vs. -16 ± 7%, P < 0.05). The reduction in the total vasodilator response (area under the curve) with NOS inhibition was also greater in young vs. older adults at all intensities. Our data suggest that contraction-induced rapid vasodilation is mediated in part by NO, and that the contribution of NO is greater in young adults.
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Affiliation(s)
- Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
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Mendes RT, Sordi R, Olchanheski LR, Machado WM, Stanczyk CP, Assreuy J, Santos FA, Fernandes D. Periodontitis increases vascular cyclooxygenase-2: potential effect on vascular tone. J Periodontal Res 2013; 49:85-92. [DOI: 10.1111/jre.12083] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2013] [Indexed: 11/30/2022]
Affiliation(s)
- R. T. Mendes
- Department of Dentistry; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - R. Sordi
- Department of Pharmacology; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
| | - L. R. Olchanheski
- Department of Pharmaceutical Sciences; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - W. M. Machado
- Department of Pharmaceutical Sciences; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - C. P. Stanczyk
- Department of Dentistry; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - J. Assreuy
- Department of Pharmacology; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
| | - F. A. Santos
- Department of Dentistry; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
| | - D. Fernandes
- Department of Pharmaceutical Sciences; Universidade Estadual de Ponta Grossa; Ponta Grossa PR Brazil
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Trott DW, Luttrell MJ, Seawright JW, Woodman CR. Aging impairs PI3K/Akt signaling and NO-mediated dilation in soleus muscle feed arteries. Eur J Appl Physiol 2013; 113:2039-46. [DOI: 10.1007/s00421-013-2639-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 03/31/2013] [Indexed: 10/27/2022]
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Angulo J, Vallejo S, El Assar M, García-Septiem J, Sánchez-Ferrer CF, Rodríguez-Mañas L. Age-related differences in the effects of α and γ peroxisome proliferator-activated receptor subtype agonists on endothelial vasodilation in human microvessels. Exp Gerontol 2012; 47:734-40. [DOI: 10.1016/j.exger.2012.06.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 06/11/2012] [Accepted: 06/29/2012] [Indexed: 01/11/2023]
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Park Y, Prisby RD, Behnke BJ, Dominguez JM, Lesniewski LA, Donato AJ, Muller-Delp J, Delp MD. Effects of aging, TNF-α, and exercise training on angiotensin II-induced vasoconstriction of rat skeletal muscle arterioles. J Appl Physiol (1985) 2012; 113:1091-100. [PMID: 22923503 DOI: 10.1152/japplphysiol.00292.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Skeletal muscle vascular resistance during physical exertion is higher with old age. The purpose of this study was to determine whether 1) aging enhances angiotensin II (ANG II)-induced vasoconstriction; 2) the proinflammatory cytokine tumor necrosis factor (TNF)-α contributes to alterations in ANG II-mediated vasoconstriction with aging; 3) exercise training attenuates putative age-associated increases in ANG II-mediated vasoconstriction; and 4) the mechanism(s) through which aging and exercise training alters ANG II-induced vasoconstriction in skeletal muscle arterioles. Male Fischer 344 rats were assigned to four groups: young sedentary (4 mo), old sedentary (24 mo), young trained, and old trained. In a separate group of young sedentary and old sedentary animals, a TNF type 1 receptor inhibitor was administered subcutaneously for 10 wk. First-order arterioles were isolated from soleus and gastrocnemius muscles for in vitro experimentation. Old age augmented ANG II-induced vasoconstriction in both soleus (young: 27 ± 3%; old: 38 ± 4%) and gastrocnemius (young: 42 ± 6%; old: 64 ± 9%) muscle arterioles; this augmented vasoconstriction was abolished with the removal of the endothelium, N(G)-nitro-l-arginine methyl ester, and chronic inhibition of TNF-α. In addition, exercise training ameliorated the age-induced increase in ANG II vasoconstriction. These findings demonstrate that old age enhances and exercise training diminishes ANG II-induced vasoconstrictor responses in skeletal muscle arterioles through an endothelium-dependent nitric oxide synthase signaling pathway. In addition, the enhancement of ANG II vasoconstriction with old age appears to be related to a proinflammatory state.
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Affiliation(s)
- Yoonjung Park
- Department of Health, Exercise and Sport Sciences, Texas Tech University, Lubbock, TX, USA
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25
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Diehl KJ, Stauffer BL, Greiner JJ, Weil BR, DeSouza CA. Nitric oxide-mediated endothlium-dependent vasodilation is impaired with borderline high-LDL cholesterol. Clin Transl Sci 2012; 5:21-6. [PMID: 22376252 DOI: 10.1111/j.1752-8062.2011.00378.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The experimental aims of this study were to determine: (1) whether nitric oxide-mediated endothelium-dependent vasodilation is blunted in adult humans with borderline high plasma low-density lipoprotein (LDL)-cholesterol compared with adults with optimal/near optimal LDL-cholesterol levels; and, if so: (2) whether the magnitude of impairment in adults with borderline high LDL-cholesterol is similar to adults with high LDL-cholesterol. Forearm blood flow responses to intraarterial infusions of acetylcholine and sodium nitroprusside were measured in 50 middle-aged (43-64 year) adults: 20 in the optimal/near optimal LDL-cholesterol range (<130 mg/dL); 20 with borderline high LDL-cholesterol (130-159 mg/dL); and 10 with high LDL-cholesterol ($160 mg/dL). In addition, blood flow responses to acetylcholine were determined in the absence and presence of the endothelial nitric oxide synthase inhibitor N(G) -monomethyl-L-arginine (L-NMMA). Vasodilation to acetylcholine was ~20% lower (p < 0.05) in the borderline high (from 4.3 ± 0.2 to 12.3 ± 0.8 mL/100 mL tissue/min) and high (from 4.3 ± 0.3 to 12.0 ± 0.5 mL/100 mL tissue/min) LDL-cholesterol groups compared with the optimal/near optimal (from 4.4 ± 0.2 to 14.5 ± 0.5 mL/100 mL tissue/min) LDL-cholesterol group. L-NMMA significantly reduced (~30%) the vasodilator response to acetylcholine in the optimal/near optimal LDL-cholesterol group but not the borderline high or high LDL-cholesterol groups. Borderline high LDL-cholesterol is associated with impaired nitric oxide-mediated endothelium-dependent vasodilation.
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Affiliation(s)
- Kyle J Diehl
- Department of Integrative Physiology, Integrative Vascular Biology Laboratory, University of Colorado, Boulder, Colorado, USA
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26
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Phillips B, Williams J, Atherton P, Smith K, Hildebrandt W, Rankin D, Greenhaff P, Macdonald I, Rennie MJ. Resistance exercise training improves age-related declines in leg vascular conductance and rejuvenates acute leg blood flow responses to feeding and exercise. J Appl Physiol (1985) 2011; 112:347-53. [PMID: 21998269 DOI: 10.1152/japplphysiol.01031.2011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One manifestation of age-related declines in vascular function is reduced peripheral (limb) blood flow and vascular conduction at rest and in response to vasodilatory stimuli such as exercise and feeding. Since, even in older age, resistance exercise training (RET) represents an efficacious strategy for increasing muscle mass and function, we hypothesized that likewise RET would improve age-related declines in leg blood flow (LBF) and vascular conductance (LVC). We studied three mixed-sex age groups (young: 18-28 yr, n = 14; middle aged: 45-55 yr, n = 20; older: 65-75 yr, n = 17) before and after 20 wk of whole body RET in the postabsorptive state (BASAL) and after unilateral leg extensions (6 × 8 repetitions; 75% 1 repetition maximum) followed by intermittent mixed-nutrient liquid feeds (∼6.5 kJ·kg(-1)·30 min(-1)), which allowed us to discern the acute effects of feeding (nonexercised leg; FED) and exercise plus feeding (exercised leg; FEDEX) on vascular function. We measured LBF using Doppler ultrasound and recorded mean arterial pressure (MAP) to calculate LVC. Our results reveal that although neither age nor RET influenced BASAL LBF, age-related declines in LBF responses to FED were eradicated by RET. Moreover, increases in LBF after FEDEX, which occurred only in young and middle-aged groups before RET (+73 ± 9%, and +90 ± 13%, P < 0.001, respectively), increased in all groups after RET (young +78 ± 10%, middle-aged +96 ± 15%, older +80 ± 19%, P < 0.001). Finally, RET robustly improved LVC under FASTED, FED, and FEDEX conditions in the older group. These data provide novel information that supports the premise that RET represents a valuable strategy to counter age-related impairments in LBF/LVC.
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Affiliation(s)
- Bethan Phillips
- University of Nottingham, School of Graduate Entry Medicine and Health, Derby, UK
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27
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Weil BR, Stauffer BL, Mestek ML, DeSouza CA. Influence of abdominal obesity on vascular endothelial function in overweight/obese adult men. Obesity (Silver Spring) 2011; 19:1742-6. [PMID: 21738236 DOI: 10.1038/oby.2011.189] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It has been suggested that body fat distribution may be an important determinant of the impact of adiposity on endothelial function. We tested the hypothesis that overweight/obese adults with abdominal adiposity exhibit worse endothelial vasodilator and fibrinolytic function than overweight/obese adults without abdominal adiposity. Sixty adult men were studied: 20 normal weight (BMI: 22.3 ± 0.7 kg/m2; waist circumference (WC): 84.9 ± 2.0 cm); 20 overweight/obese with WC <102 cm (29.2 ± 0.3 kg/m2; 98.1 ± 0.7 cm); and 20 overweight/obese with WC ≥102 cm (30.0 ± 0.4 kg/m2; 106.7 ± 1.0 cm). Forearm blood flow (FBF) responses to intra-arterial acetylcholine and sodium nitroprusside (SNP) were measured. Additionally, net endothelial release of tissue-type plasminogen activator (t-PA) was determined in response to bradykinin (BK) and SNP. Overweight/obese men demonstrated lower (~30%; P < 0.01) FBF responses to acetylcholine compared with normal weight controls. However, there were no differences in FBF responses to acetylcholine between overweight/obese men with (4.1 ± 0.3-10.8 ± 1.3 ml/100 ml tissue/min) and without (4.5 ± 0.3-11.6 ± 0.8 ml/100 ml tissue/min) abdominal adiposity. Similarly, endothelial t-PA release to BK was lower (~40%; P < 0.05) in the overweight/obese men compared with normal weight controls; however, t-PA release was not different between the overweight/obese men with (-0.7 ± 0.4-40.4 ± 6.2 ng/100 ml tissue/min) and without (-0.3 ± 0.6-48 ± 7.5 ng/100 ml tissue/min) abdominal adiposity. These results indicate that abdominal obesity is not associated with greater impairment in endothelial vasodilation and fibrinolytic capacity in overweight/obese men. Excess adiposity, regardless of anatomical distribution pattern, is associated with impaired endothelial function.
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Affiliation(s)
- Brian R Weil
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
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Crecelius AR, Kirby BS, Richards JC, Garcia LJ, Voyles WF, Larson DG, Luckasen GJ, Dinenno FA. Mechanisms of ATP-mediated vasodilation in humans: modest role for nitric oxide and vasodilating prostaglandins. Am J Physiol Heart Circ Physiol 2011; 301:H1302-10. [PMID: 21784984 DOI: 10.1152/ajpheart.00469.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ATP is an endothelium-dependent vasodilator, and findings regarding the underlying signaling mechanisms are equivocal. We sought to determine the independent and interactive roles of nitric oxide (NO) and vasodilating prostaglandins (PGs) in ATP-mediated vasodilation in young, healthy humans and determine whether any potential role was dependent on ATP dose or the timing of inhibition. In protocol 1 (n = 18), a dose-response curve to intrabrachial infusion of ATP was performed before and after both single and combined inhibition of NO synthase [N(G)-monomethyl-L-arginine (L-NMMA)] and cyclooxygenase (ketorolac). Forearm blood flow (FBF) was measured via venous occlusion plethysmography and forearm vascular conductance (FVC) was calculated. In this protocol, neither individual nor combined NO/PG inhibition had any effect on the vasodilatory response (P = 0.22-0.99). In protocol 2 (n = 16), we determined whether any possible contribution of both NO and PGs to ATP vasodilation was greater at low vs. high doses of ATP and whether inhibition during steady-state infusion of the respective dose of ATP impacted the dilation. FBF in this protocol was measured via Doppler ultrasound. In protocol 2, infusion of low (n = 8)- and high-dose (n = 8) ATP for 5 min evoked a significant increase in FVC above baseline (low = 198 ± 24%; high = 706 ± 79%). Infusion of L-NMMA and ketorolac together reduced steady-state FVC during both low- and high-dose ATP (P < 0.05), and in a subsequent trial with continuous NO/PG blockade, the vasodilator response from baseline to 5 min of steady-state infusion was similarly reduced for both low (ΔFVC = -31 ± 11%)- and high-dose ATP (ΔFVC -25 ± 11%; P = 0.70 low vs. high dose). Collectively, our findings indicate a potential modest role for NO and PGs in the vasodilatory response to exogenous ATP in the human forearm that does not appear to be dose or timing dependent; however, this is dependent on the method for assessing forearm vascular responses. Importantly, the majority of ATP-mediated vasodilation is independent of these putative endothelium-dependent pathways in humans.
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Affiliation(s)
- Anne R Crecelius
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Vascular Physiology Research Group, Department of Biomedical Sciences, Colorado State University, Fort Collins 80523-1582, USA
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Hirai DM, Copp SW, Hageman KS, Poole DC, Musch TI. Aging alters the contribution of nitric oxide to regional muscle hemodynamic control at rest and during exercise in rats. J Appl Physiol (1985) 2011; 111:989-98. [PMID: 21757576 DOI: 10.1152/japplphysiol.00490.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Advanced age is associated with altered skeletal muscle hemodynamic control during the transition from rest to exercise. This study investigated the effects of aging on the functional role of nitric oxide (NO) in regulating total, inter-, and intramuscular hindlimb hemodynamic control at rest and during submaximal whole body exercise. We tested the hypothesis that NO synthase inhibition (N(G)-nitro-l-arginine methyl ester, l-NAME; 10 mg/kg) would result in attenuated reductions in vascular conductance (VC) primarily in oxidative muscles in old compared with young rats. Total and regional hindlimb muscle VCs were determined via radiolabeled microspheres at rest and during treadmill running (20 m/min, 5% grade) in nine young (6-8 mo) and seven old (27-29 mo) male Fisher 344 × Brown Norway rats. At rest, l-NAME increased mean arterial pressure (MAP) significantly by ∼17% and 21% in young and old rats, respectively. During exercise, l-NAME increased MAP significantly by ∼13% and 19% in young and old rats, respectively. Compared with young rats, l-NAME administration in old rats evoked attenuated reductions in 1) total hindlimb VC during exercise (i.e., down by ∼23% in old vs. 43% in young rats; P < 0.05), and 2) VC in predominantly oxidative muscles both at rest and during exercise (P < 0.05). Our results indicate that the dependency of highly oxidative muscles on NO-mediated vasodilation is markedly diminished, and therefore mechanisms other than NO-mediated vasodilation control the bulk of the increase in skeletal muscle VC during the transition from rest to exercise in old rats. Reduced NO contribution to vasomotor control with advanced age is associated with blood flow redistribution from highly oxidative to glycolytic muscles during exercise.
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Affiliation(s)
- Daniel M Hirai
- Clarenburg Research Laboratory, Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State Univ., Manhattan, KS 66506-5802, USA
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Abstract
Advancing age is the major risk factor for the development of CVD (cardiovascular diseases). This is attributable, in part, to the development of vascular endothelial dysfunction, as indicated by reduced peripheral artery EDD (endothelium-dependent dilation) in response to chemical [typically ACh (acetylcholine)] or mechanical (intravascular shear) stimuli. Reduced bioavailability of the endothelium-synthesized dilating molecule NO (nitric oxide) as a result of oxidative stress is the key mechanism mediating reduced EDD with aging. Vascular oxidative stress increases with age as a consequence of greater production of reactive oxygen species (e.g. superoxide) without a compensatory increase in antioxidant defences. Sources of increased superoxide production include up-regulation of the oxidant enzyme NADPH oxidase, uncoupling of the normally NO-producing enzyme, eNOS (endothelial NO synthase) (due to reduced availability of the cofactor tetrahydrobiopterin) and increased mitochondrial synthesis during oxidative phosphorylation. Increased bioactivity of the potent endothelial-derived constricting factor ET-1 (endothelin-1), reduced endothelial production of/responsiveness to dilatory prostaglandins, the development of vascular inflammation, formation of AGEs (advanced glycation end-products), an increased rate of endothelial apoptosis and reduced expression of oestrogen receptor α (in postmenopausal females) also probably contribute to impaired EDD with aging. Several lifestyle and biological factors modulate vascular endothelial function with aging, including regular aerobic exercise, dietary factors (e.g. processed compared with non-processed foods), body weight/fatness, vitamin D status, menopause/oestrogen deficiency and a number of conventional and non-conventional risk factors for CVD. Given the number of older adults now and in the future, more information is needed on effective strategies for the prevention and treatment of vascular endothelial aging.
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Boyer L, Chaar V, Pelle G, Maitre B, Chouaid C, Covali-Noroc A, Zerah F, Bucherer C, Lacombe C, Housset B, Dubois-Randé JL, Boczkowski J, Adnot S. Effects of polycythemia on systemic endothelial function in chronic hypoxic lung disease. J Appl Physiol (1985) 2011; 110:1196-203. [DOI: 10.1152/japplphysiol.01204.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a major risk factor for cardiovascular disease. Polycythemia, a common complication of hypoxic COPD, may affect systemic vascular function by altering blood viscosity, vessel wall shear stress (WSS), and endothelium-derived nitric oxide (NO) release. Here, we evaluated the effects of hypoxia-related polycythemia on systemic endothelial function in patients with COPD. We investigated blood viscosity, WSS, and endothelial function in 15 polycythemic and 13 normocythemic patients with COPD of equal severity, by recording brachial artery diameter variations in response to hyperemia and by using venous occlusion plethysmography (VOP) to measure forearm blood flow (FBF) responses to a brachial artery infusion of acetylcholine (ACh), bradykinin (BK), sodium nitroprusside (SNP), substance P (SP), isoptin, and N-monomethyl-l-arginine (l-NMMA). At baseline, polycythemic patients had higher blood viscosity and larger brachial artery diameter than normocythemic patients but similar calculated WSS. Flow-mediated brachial artery vasodilation was increased in the polycythemic patients, in proportion to the hemoglobin levels. ACh-induced vasodilation was markedly impaired in the polycythemic patients and negatively correlated with hemoglobin levels. FBF responses to endothelium- (BK, SP) and non-endothelium-dependent (SNP, isoptin) vasodilators were not significantly different between the two groups. l-NMMA infusion induced a similar vasoconstrictor response in both groups, in accordance with their similar baseline WSS. In conclusion, systemic arteries in polycythemic patients adjust appropriately to chronic or acute WSS elevations by appropriate basal and stimulated NO release. Overall, our results suggest that moderate polycythemia has no adverse effect on vascular function in COPD.
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Affiliation(s)
- Laurent Boyer
- Hôpital Henri Mondor, Service de Physiologie Explorations Fonctionnelles, Assistance Publique-Hôpitaux de Paris, Université Paris-Est Créteil Val de Marne, Créteil
- INSERM, Unité U955, Créteil
| | | | - Gabriel Pelle
- Hôpital Henri Mondor, Service de Physiologie Explorations Fonctionnelles, Assistance Publique-Hôpitaux de Paris, Université Paris-Est Créteil Val de Marne, Créteil
- INSERM, Unité U955, Créteil
| | - Bernard Maitre
- INSERM, Unité U955, Créteil
- Centre Hospitalier Intercommunal de Créteil, Service de Pneumologie et de Pathologie Professionnelle, Créteil
| | | | - Ala Covali-Noroc
- Hôpital Henri Mondor, Service de Physiologie Explorations Fonctionnelles, Assistance Publique-Hôpitaux de Paris, Université Paris-Est Créteil Val de Marne, Créteil
| | - Françoise Zerah
- Hôpital Henri Mondor, Service de Physiologie Explorations Fonctionnelles, Assistance Publique-Hôpitaux de Paris, Université Paris-Est Créteil Val de Marne, Créteil
| | - Catherine Bucherer
- Hôpital Henri Mondor, Service de Physiologie Explorations Fonctionnelles, Assistance Publique-Hôpitaux de Paris, Université Paris-Est Créteil Val de Marne, Créteil
| | - Catherine Lacombe
- Hôpital Henri Mondor, Service de Physiologie Explorations Fonctionnelles, Assistance Publique-Hôpitaux de Paris, Université Paris-Est Créteil Val de Marne, Créteil
| | - Bruno Housset
- INSERM, Unité U955, Créteil
- Centre Hospitalier Intercommunal de Créteil, Service de Pneumologie et de Pathologie Professionnelle, Créteil
| | - Jean-Luc Dubois-Randé
- INSERM, Unité U955, Créteil
- Hôpital Henri Mondor, Service de Cardiologie, Créteil, France
| | - Jorge Boczkowski
- INSERM, Unité U955, Créteil
- Centre Hospitalier Intercommunal de Créteil, Service de Pneumologie et de Pathologie Professionnelle, Créteil
| | - Serge Adnot
- Hôpital Henri Mondor, Service de Physiologie Explorations Fonctionnelles, Assistance Publique-Hôpitaux de Paris, Université Paris-Est Créteil Val de Marne, Créteil
- INSERM, Unité U955, Créteil
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Kirby BS, Crecelius AR, Voyles WF, Dinenno FA. Modulation of postjunctional α-adrenergic vasoconstriction during exercise and exogenous ATP infusions in ageing humans. J Physiol 2011; 589:2641-53. [PMID: 21486772 DOI: 10.1113/jphysiol.2010.204081] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The ability to modulate sympathetic α-adrenergic vasoconstriction in contracting muscle is impaired with age. In young adults, adenosine triphosphate (ATP) has been shown to blunt sympathetic vasoconstrictor responsiveness similar to exercise. Therefore, we tested the hypothesis that modulation of postjunctional α-adrenergic vasoconstriction to exogenous ATP is impaired in ageing humans.We measured forearm blood flow (FBF; Doppler ultrasound) and calculated vascular conductance (FVC) to intra-arterial infusions of phenylephrine (α₁-agonist) and dexmedetomidine (α₂-agonist) during rhythmic handgrip exercise (15% MVC), a control non-exercise vasodilator condition (adenosine), and ATP infusion in seven older (64 ± 3 years) and seven young (22 ± 1 years) healthy adults. Forearm hyperaemia was matched across all vasodilatating conditions. During adenosine, forearm vasoconstrictor responses to direct α₁-stimulation were lower in older compared with young adults (ΔFVC=-25 ± 3% vs. -41 ± 5%; P <0.05), whereas the responses to α₂-stimulation were not different (-35±6% vs. -44 ± 8%; NS). During exercise, α₁-mediated vasoconstriction was significantly blunted compared with adenosine in both young (-9 ± 2% vs. -41 ± 5%) and older adults (-15 ± 2% vs. -25 ± 3%); however, the magnitude of sympatholysis was reduced in older adults (32 ± 13 vs. 74 ± 8%; P <0.05). Similarly, α₂-mediated vasoconstriction during exercise was significantly blunted in both young (-15 ± 4% vs. -44 ± 8%) and older adults (-26 ± 3% vs. -35 ± 6%), however the magnitude of sympatholysis was reduced in older adults (19 ± 8% vs. 60 ± 10%; P <0.05). During ATP, both α₁- and α₂-mediated vasoconstriction was nearly abolished in young and older adults (ΔFVC ∼ -5%), and the magnitude of sympatholysis was similar in both age groups (∼85-90%). Our findings indicate that the ability to modulate postjunctional α-adrenergic vasoconstriction during exercise is impaired with age, whereas the sympatholytic effect of exogenous ATP is preserved. Thus, if impairments in vascular control during exercise in older adults involve vasoactive ATP, we speculate that circulating ATP is reduced with advancing age.
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Affiliation(s)
- Brett S Kirby
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Vascular Physiology Research Group, Colorado State University, Fort Collins, CO 80523-1582, USA
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Endothelin-1 vasoconstriction and the age-related decline in endothelium-dependent vasodilatation in men. Clin Sci (Lond) 2011; 120:485-91. [DOI: 10.1042/cs20100475] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ET (endothelin)-1, a potent vasoconstrictor peptide released by the endothelium, plays an important role in vasomotor regulation and has been linked to diminished endothelial vasodilator capacity in several pathologies associated with human aging, including hypertension, Type 2 diabetes and coronary artery disease. However, it is currently unknown whether the decline in endothelial vasodilatation with advancing age is due to elevated ET-1 vasconstrictor activity. Accordingly, we tested the hypothesis that the age-related impairment in ACh (acetylcholine)-mediated endothelium-dependent vasodilatation is due, at least in part, to increased ET-1-mediated vasoconstrictor tone. FBF (forearm blood flow) responses to ACh, SNP (sodium nitroprusside) and BQ-123 (ETA receptor blocker) were determined in 14 young (age, 25±1 years) and 14 older (age, 61±2 years) healthy non-obese men. Additionally, FBF responses to ACh were determined in the presence of ETA blockade. Vasodilatation to ACh was lower (approx. 25%; P<0.05) in the older men (from 4.9±0.2 to 13.9±0.9 ml·100 ml−1 of tissue·min−1) compared with the young men (4.6±0.3 to 17.2±1.0 ml·100 ml−1 of tissue·min−1). There were no differences in FBF responses to SNP between the young (4.8±0.3 to 18.5±0.3 ml·100 ml−1 of tissue·min−1) and older (5.1±0.3 to 17.3±0.8 ml·100 ml−1 of tissue·min−1) men. In the young men, resting FBF was not significantly altered by BQ-123, whereas, in the older men, FBF increased approx. 25% in response to BQ-123 infusion (P<0.05). Co-infusion of ACh with BQ-123 resulted in an approx. 20% increase in the ACh-induced vasodilatation in older men compared with saline. In contrast, FBF responses to ACh were not significantly altered by ETA blockade in the young men. In conclusion, these results demonstrate that ET-1 vasoconstrictor activity contributes, at least in part, to diminished endothelium-dependent vasodilatation in older men.
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Kirby BS, Crecelius AR, Voyles WF, Dinenno FA. Vasodilatory responsiveness to adenosine triphosphate in ageing humans. J Physiol 2011; 588:4017-27. [PMID: 20807789 DOI: 10.1113/jphysiol.2010.197814] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Endothelium-dependent vasodilatation is reduced with advancing age in humans, as evidenced by blunted vasodilator responsiveness to acetylcholine (ACh). Circulating adenosine triphosphate (ATP) has been implicated in the control of skeletal muscle vascular tone during mismatches in oxygen delivery and demand (e.g. exercise) via binding to purinergic receptors (P2Y) on the endothelium evoking subsequent vasodilatation, and ageing is typically associated with reductions in muscle blood flow under such conditions. Therefore, we tested the hypothesis that ATP-mediated vasodilatation is impaired with age in healthy humans. We measured forearm blood flow (venous occlusion plethysmography) and calculated vascular conductance (FVC) responses to local intra-arterial infusions of ACh, ATP, and sodium nitroprusside (SNP) before and during ascorbic acid (AA) infusion in 13 young and 13 older adults. The peak increase in FVC to ACh was significantly impaired in older compared with young adults (262 ± 71% vs. 618 ± 97%; P < 0.05), and this difference was abolished during AA infusion (510 ± 82% vs. 556 ± 71%; not significant, NS). In contrast, peak FVC responses were not different between older and young adults to either ATP (675 ± 105% vs. 734 ± 126%) or SNP (1116 ± 111% vs. 1138 ± 148%) and AA infusion did not alter these responses in either age group (both NS). In another group of six young and six older adults, we determined whether vasodilator responses to adenosine and ATP were influenced by P1-receptor blockade via aminophylline. The peak FVC responses to adenosine were not different in young (350 ± 65%) versus older adults (360 ± 80%), and aminophylline blunted these responses by ∼50% in both groups. The peak FVC responses to ATP were again not different in young and older adults, and aminophylline did not impact the vasodilatation in either group. Thus, in contrast to the observed impairments in ACh responses, the vasodilatory response to exogenous ATP is not reduced with age in healthy humans. Further, our data also indicate that adenosine mediated vasodilatation is not reduced with age, and that ATP-mediated vasodilatation is independent of P1-receptor stimulation in both young and older adults.
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Affiliation(s)
- Brett S Kirby
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523-1582, USA
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35
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Tanindi A, Cengel A, Akyel A, Akinci S. Relief of angina pectoris when carrying heavy loads with the left hand in a patient with previous coronary artery bypass graft operation who has severe exercise angina: a case report. Clin Cardiol 2010; 33:E73-5. [PMID: 20845407 DOI: 10.1002/clc.20436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2008] [Accepted: 02/24/2008] [Indexed: 11/10/2022] Open
Abstract
In patients with known coronary artery disease and/or a history of revascularization, angina pectoris or unstable coronary syndromes are usually attributed to the progression of atherosclerotic lesions rather than an unrecognized great vessel disease. However, for patients with a previous coronary artery bypass graft operation (CABG), during which a left internal mammary artery (LIMA) conduit has been used, great vessel disease, especially subclavian artery stenosis should also be suspected. We present a case of a patient with a LIMA conduit who has angina pectoris on exertion, but interestingly the pain is relieved when he carries heavy loads with his left hand, which can be due to increased blood flow to the LIMA conduit during heavy lifting because of increased peripheral resistance.
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Affiliation(s)
- Asli Tanindi
- Gazi University, Department of Cardiology, Besevler Ankara, Turkey.
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36
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Van Craenenbroeck EM, Conraads VM. Endothelial progenitor cells in vascular health: focus on lifestyle. Microvasc Res 2010; 79:184-92. [PMID: 20053364 DOI: 10.1016/j.mvr.2009.12.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 12/25/2009] [Indexed: 01/04/2023]
Abstract
Endothelial dysfunction, which is considered the functional equivalent of a disrupted balance between endothelial injury and repair, precedes overt atherosclerosis by many years. Although this phenomenon is part of the normal aging process, prevention of early and progressive endothelial dysfunction has become an important therapeutic target. Evidence has accumulated to show that endothelial progenitor cells (EPC), contribute substantially to preservation of a structurally and functionally intact endothelium. There has been considerable progress in our understanding of the various cell types that were in the past all covered by the term "EPC." EPC home to sites of endothelial injury and ischemia, where they proliferate, differentiate and integrate into the endothelial layer or exert a paracrine function by producing vascular growth factors. Although more emphasis has been put on the pharmacological approach of endothelial dysfunction, the effect of a healthy lifestyle, via mobilization and functional improvement of EPC, is increasingly recognized. This review will focus on successful lifestyle interventions that aim to maintain vascular health through beneficial actions on cell populations with vasculogenic potential ("EPC"). The role of physical activity and dietary recommendations, which are considered essential elements of a healthy lifestyle, will be particularly emphasized. A thorough understanding of the physiology of endothelial benefits, derived from such interventions, may help to implement these measures on top of classical drug therapy, but also provides a solid basis for primary prevention. The effects of additional elements of a comprehensive lifestyle advice, such as smoking cessation, weight and stress reduction, also comprise a modulation of EPC function and circulating numbers and are therefore included in this review as well.
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37
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Stauffer BL, Westby CM, Greiner JJ, Van Guilder GP, Desouza CA. Sex differences in endothelin-1-mediated vasoconstrictor tone in middle-aged and older adults. Am J Physiol Regul Integr Comp Physiol 2009; 298:R261-5. [PMID: 19939973 DOI: 10.1152/ajpregu.00626.2009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The prevalence of cardiovascular disease is lower in middle-aged and older women than men. Increased endothelin-1-mediated vasoconstriction has been linked to the etiology of a number of cardiovascular diseases, including atherosclerosis, heart failure, and hypertension. It is unknown whether a sex difference in endothelin-1-mediated vasoconstrictor tone exists in middle-aged and older adults. Therefore, we tested the hypothesis that middle-aged and older men would demonstrate greater ET-1-mediated vasoconstrictor tone than age-matched women. Forearm blood flow in response to intra-arterial infusions of endothelin (ET)-1, BQ-123 (a selective ET(A) receptor antagonist), and BQ-788 (a selective ET(B) receptor antagonist) was assessed by venous occlusion plethysmography in 21 women (age: 58 + or - 1 yr; body mass index: 26.0 + or - 1.0 kg/m(2)) and 25 men (age: 57 + or - 2 yr; body mass index: 26.8 + or - 0.7 kg/m(2)). In response to BQ-123, the increase in forearm blood flow from baseline was significantly higher in the men than the women (24 + or - 5% vs. 9 + or - 5%; P < 0.05). In contrast, the increase in forearm blood flow in response to BQ-123 coinfused with BQ-788 was greater in the women than the men, such that the maximum vasodilation to dual endothelin receptor blockade was similar between men and women (approximately 25%). There was no difference in the vasoconstrictor response to ET-1 between the sexes. These results indicate that middle-aged and older men are under greater ET(A) receptor-mediated vasoconstrictor tone than age-matched women. Since the ET(A) receptor is the predominant receptor subtype in the coronary vasculature, this sex difference in vasoconstrictor tone may be a mechanism contributing to the sex difference in the prevalence of coronary heart disease in middle-aged and older adults.
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Affiliation(s)
- Brian L Stauffer
- Integrative Vascular Biology Laboratory, Dept. of Integrative Physiology, Univ. of Colorado, 354 UCB, Boulder, CO 80309, USA.
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38
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Rodríguez-Mañas L, El-Assar M, Vallejo S, López-Dóriga P, Solís J, Petidier R, Montes M, Nevado J, Castro M, Gómez-Guerrero C, Peiró C, Sánchez-Ferrer CF. Endothelial dysfunction in aged humans is related with oxidative stress and vascular inflammation. Aging Cell 2009; 8:226-38. [PMID: 19245678 DOI: 10.1111/j.1474-9726.2009.00466.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Vascular endothelial dysfunction occurs during the human aging process, and it is considered as a crucial event in the development of many vasculopathies. We investigated the underlying mechanisms of this process, particularly those related with oxidative stress and inflammation, in the vasculature of subjects aged 18-91 years without cardiovascular disease or risk factors. In isolated mesenteric microvessels from these subjects, an age-dependent impairment of the endothelium-dependent relaxations to bradykinin was observed. Similar results were observed by plethysmography in the forearm blood flow in response to acetylcholine. In microvessels from subjects aged less than 60 years, most of the bradykinin-induced relaxation was due to nitric oxide release while the rest was sensitive to cyclooxygenase (COX) blockade. In microvessels from subjects older than 60 years, this COX-derived vasodilatation was lost but a COX-derived vasoconstriction occurred. Evidence for age-related vascular oxidant and inflammatory environment was observed, which could be related to the development of endothelial dysfunction. Indeed, aged microvessels showed superoxide anions (O(2)(-)) and peroxynitrite (ONOO(-)) formation, enhancement of NADPH oxidase and inducible NO synthase expression. Pharmacological interference of COX, thromboxane A(2)/prostaglandin H(2) receptor, O(2)(-), ONOO(-), inducible NO synthase, and NADPH oxidase improved the age-related endothelial dysfunction. In situ vascular nuclear factor-kappaB activation was enhanced with age, which correlated with endothelial dysfunction. We conclude that the age-dependent endothelial dysfunction in human vessels is due to the combined effect of oxidative stress and vascular wall inflammation.
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Nicholson WT, Vaa B, Hesse C, Eisenach JH, Joyner MJ. Aging is associated with reduced prostacyclin-mediated dilation in the human forearm. Hypertension 2009; 53:973-8. [PMID: 19414649 DOI: 10.1161/hypertensionaha.108.121483] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aging is associated with reduced endothelial function. There is indirect evidence for reduced prostacyclin (PGI(2))-mediated vasodilation with aging, but it is unknown whether this is because of reduced dilation to PGI(2) or altered production. In addition, the contribution of endothelial NO to PGI(2)-mediated dilation is unknown. Using plethysmography to determine forearm blood flow, we studied the effect of PGI(2) in 10 older (61 to 73 years) and 10 younger (19 to 45 years) subjects using 3 escalating intra-arterial doses of PGI(2) (epoprostenol). PGI(2) was also administered after NO synthase inhibition with N(G)-monomethyl-l-arginine acetate. The percent of change in forearm vascular conductance (mean+/-SEM) from baseline after PGI(2) was significantly lower (P=0.002) in the aging individuals (52+/-11%, 164+/-23%, and 221+/-27% versus 115+/-20%, 249+/-19%, and 370+/-35%). In addition, the group-by-dose interaction was also significant (P=0.018). After NO synthase inhibition, the dose-response curve to PGI(2) was blunted in the young subjects but unchanged in the older subjects; the difference between the groups was no longer significant. Our data suggest that the reduced dilator effects of PGI(2) in older individuals are attributable to a reduction in the contribution of endothelial-derived NO versus alterations in the direct effects of PGI(2) on vascular smooth muscle.
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Affiliation(s)
- Wayne T Nicholson
- Department of Anesthesiology, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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Kirby BS, Voyles WF, Simpson CB, Carlson RE, Schrage WG, Dinenno FA. Endothelium-dependent vasodilatation and exercise hyperaemia in ageing humans: impact of acute ascorbic acid administration. J Physiol 2009; 587:1989-2003. [PMID: 19307300 DOI: 10.1113/jphysiol.2008.167320] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Age-related increases in oxidative stress impair endothelium-dependent vasodilatation in humans, leading to the speculation that endothelial dysfunction contributes to impaired muscle blood flow and vascular control during exercise in older adults. We directly tested this hypothesis in 14 young (22 +/- 1 years) and 14 healthy older men and women (65 +/- 2 years). We measured forearm blood flow (FBF; Doppler ultrasound) and calculated vascular conductance (FVC) responses to single muscle contractions at 10, 20 and 40% maximum voluntary contraction (MVC) before and during ascorbic acid (AA) infusion, and we also determined the effects of AA on muscle blood flow during mild (10% MVC) continuous rhythmic handgrip exercise. For single contractions, the peak rapid hyperaemic responses to all contraction intensities were impaired approximately 45% in the older adults (all P < 0.05), and AA infusion did not impact the responses in either age group. For the rhythmic exercise trial, FBF (approximately 28%) and FVC (approximately 31%) were lower (P = 0.06 and 0.05) in older versus young adults after 5 min of steady-state exercise with saline. Subsequently, AA was infused via brachial artery catheter for 10 min during continued exercise. AA administration did not significantly influence FBF or FVC in young adults (1-3%; P = 0.24-0.59), whereas FBF increased 34 +/- 7% in older adults at end-exercise, and this was due to an increase in FVC (32 +/- 7%; both P < 0.05). This increase in FBF and FVC during exercise in older adults was associated with improvements in vasodilator responses to acetylcholine (ACh; endothelium dependent) but not sodium nitroprusside (SNP; endothelium independent). AA had no effect on ACh or SNP responses in the young. We conclude that acute AA administration does not impact the observed age-related impairment in the rapid hyperaemic response to brief muscle contractions in humans; however, it does significantly increase muscle blood flow during continuous dynamic exercise in older adults, and this is probably due (in part) to an improvement in endothelium-dependent vasodilatation.
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Affiliation(s)
- Brett S Kirby
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523-1582, USA
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Lesniewski LA, Connell ML, Durrant JR, Folian BJ, Anderson MC, Donato AJ, Seals DR. B6D2F1 Mice are a suitable model of oxidative stress-mediated impaired endothelium-dependent dilation with aging. J Gerontol A Biol Sci Med Sci 2009; 64:9-20. [PMID: 19211548 DOI: 10.1093/gerona/gln049] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
To determine if B6D2F1 mice represent a suitable model of oxidative stress-mediated impaired endothelium-dependent dilation (EDD) with aging, mice were studied at 6.9 +/- 0.3 and 31.9 +/- 0.6 months. EDD to acetylcholine (ACh) was 26% (p < .001) and 12% (p < .001) lower, respectively, in isolated carotid (n = 10-11) and femoral (n = 10) arteries from older mice, and reductions in arterial pressure to systemic ACh infusion were smaller in older mice (n = 6-10; p < .01). Nitrotyrosine was marked in aorta of older mice (p < .05, n = 4). Superoxide production in carotid arteries was greater (p < .05), and TEMPOL restored dilation in carotid arteries and systemically in older mice. N(G)-nitro-l-arginine methyl ester (l-NAME) reduced carotid artery dilation in young more than older mice, whereas TEMPOL restored the effects of l-NAME in older mice. Carotid artery stiffness was increased in older compared with young mice (p = .04). Our results provide the first comprehensive evidence that B6D2F1 mice are a useful model for investigating mechanisms of reduced nitric oxide-dependent, oxidative stress-associated EDD and increased arterial stiffness with aging.
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Affiliation(s)
- Lisa A Lesniewski
- Department of Integrative Physiology, University of Colorado at Boulder, 80309, USA.
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Walsh T, Donnelly T, Lyons D. Impaired endothelial nitric oxide bioavailability: a common link between aging, hypertension, and atherogenesis? J Am Geriatr Soc 2008; 57:140-5. [PMID: 19054194 DOI: 10.1111/j.1532-5415.2008.02051.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Endothelial-derived nitric oxide (NO) is responsible for maintaining continuous vasodilator tone and for regulating local perfusion and systemic blood pressure. It also has significant antiproliferative effects on vascular smooth muscle and platelet anti-aggregatory effects. Impaired endothelial-dependent (NO mediated) vasorelaxation is observed in most animal and human models of healthy aging. It also occurs in age-associated conditions such as atherosclerosis and hypertension. Such "endotheliopathy" increases vascular risk in older adults. Studies have indicated that pharmacotherapeutic intervention with angiotensin-converting enzyme inhibitors and 3-hydroxy-3-methyl-glutaryl coenzyme-A reductase inhibitors may improve NO-mediated vasomotor function. This review, evaluates the association between impaired endothelial NO bioavailability, accelerated vascular aging, and the age-associated conditions hypertension and atherogenesis. This is important, because pharmacotherapy aimed at improving endothelial NO bioavailability could modify age-related vascular disease and transform age into a potentially modifiable vascular risk factor, at least in a subpopulation of older adults.
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Affiliation(s)
- Thomas Walsh
- Department of Medical Gerontology, Mid Western Regional Hospital, University of Limerick, Dooradoyle, Ireland.
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Van Guilder GP, Stauffer BL, Greiner JJ, Desouza CA. Impaired endothelium-dependent vasodilation in overweight and obese adult humans is not limited to muscarinic receptor agonists. Am J Physiol Heart Circ Physiol 2008; 294:H1685-92. [PMID: 18281379 PMCID: PMC3686114 DOI: 10.1152/ajpheart.01281.2007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Muscarinic receptor agonists have primarily been used to characterize endothelium-dependent vasodilator dysfunction with overweight/obesity. Reliance on a single class of agonist, however, yields limited, and potentially misleading, information regarding endothelial vasodilator capacity. The aims of this study were to determine 1) whether the overweight/obesity-related reduction in endothelium-dependent vasodilation extends beyond muscarinic receptor agonists and 2) whether the contribution of nitric oxide (NO) to endothelium-dependent vasodilation is reduced in overweight/obese adults. Eighty-six middle-aged and older adults were studied: 42 normal-weight (54 +/- 1 yr, 21 men and 21 women, body mass index = 23.4 +/- 0.3 kg/m(2)) and 44 overweight/obese (54 +/- 1 yr, 28 men and 16 women, body mass index = 30.3 +/- 0.6 kg/m(2)) subjects. Forearm blood flow (FBF) responses to intra-arterial infusions of acetylcholine in the absence and presence of the endothelial NO synthase inhibitor N(G)-monomethyl-l-arginine, methacholine, bradykinin, substance P, isoproterenol, and sodium nitroprusside were measured by strain-gauge plethysmography. FBF responses to each endothelial agonist were significantly blunted in the overweight/obese adults. Total FBF (area under the curve) to acetylcholine (50 +/- 5 vs. 79 +/- 4 ml/100 ml tissue), methacholine (55 +/- 4 vs. 86 +/- 5 ml/100 ml tissue), bradykinin (62 +/- 5 vs. 85 +/- 4 ml/100 ml tissue), substance P (37 +/- 4 vs. 57 +/- 5 ml/100 ml tissue), and isoproterenol (62 +/- 4 vs. 82 +/- 6 ml/100 ml tissue) were 30%-40% lower in the overweight/obese than normal-weight adults. N(G)-monomethyl-l-arginine significantly reduced the FBF response to acetylcholine to the same extent in both groups. There were no differences between the groups in the FBF responses to sodium nitroprusside. These results indicate that agonist-stimulated endothelium-dependent vasodilation is universally impaired with overweight/obesity. Moreover, this impairment appears to be independent of NO.
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Affiliation(s)
- Gary P Van Guilder
- Dept. of Integrative Physiology, Univ. of Colorado, 354 UCB, Boulder, CO 80309. )
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Van Guilder GP, Westby CM, Greiner JJ, Stauffer BL, DeSouza CA. Endothelin-1 Vasoconstrictor Tone Increases With Age in Healthy Men But Can Be Reduced by Regular Aerobic Exercise. Hypertension 2007; 50:403-9. [PMID: 17576858 DOI: 10.1161/hypertensionaha.107.088294] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Increased endothelin-1–mediated vasoconstrictor tone has been linked to the etiology of a number of pathologies associated with human aging, including hypertension, congestive heart failure, and coronary artery disease. However, it is currently unclear whether aging, per se, is associated with enhanced endothelin-1 system activity. We hypothesized that endothelin-1 vasoconstrictor activity is greater in healthy older compared with young men and that regular aerobic exercise is an effective intervention for reducing endothelin-1 vasoconstrictor tone in older previously sedentary men. Forearm blood flow (plethysmography) responses to intra-arterial infusion of endothelin-1 (5 pmol/min; for 20 minutes) and selective (BQ-123; 100 nmol/min; for 60 minutes) and nonselective (BQ-123+BQ-788; 100 nmol/min; for 60 minutes) endothelin-1 receptor blockade were determined in 28 healthy, sedentary men: 13 younger (age: 27±1 years) and 15 older (age: 62±2 years). The vasoconstrictor response to endothelin-1 was significantly blunted (≈65%) in the older versus younger men. In response to BQ-123, resting forearm blood flow increased (≈20%;
P
<0.05) in the older but not in the younger men. The addition of BQ-788 to BQ-123 did not significantly affect the blood flow responses to BQ-123 in either group. Eight of the 15 older sedentary men completed a 3-month aerobic exercise intervention. After the intervention, the vasoconstrictor response to endothelin-1 was markedly increased (225%;
P
<0.05), whereas BQ-123 resulted in modest vasoconstriction in the previously sedentary older men. These results demonstrate that endothelin-1–mediated vasoconstrictor tone increases with age in healthy men but can be alleviated with regular aerobic exercise.
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Affiliation(s)
- Gary P Van Guilder
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, 354 UCB, Boulder, CO 80309, USA
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Beckman JA, Goldfine AB, Dunaif A, Gerhard-Herman M, Creager MA. Endothelial function varies according to insulin resistance disease type. Diabetes Care 2007; 30:1226-32. [PMID: 17261751 DOI: 10.2337/dc06-2142] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE We examined the relationship between insulin resistance and vascular function in three insulin-resistant states (type 2 diabetes, non-HIV lipodystrophic diabetes, and nondiabetic polycystic ovary syndrome [PCOS]) and in healthy control subjects. RESEARCH DESIGN AND METHODS The population included 12 women with type 2 diabetes, 6 with lipodystrophic diabetes, 10 with PCOS, and 19 healthy female subjects. Metabolic measures included insulin sensitivity by the homeostasis model assessment, lipids, free fatty acids, and adiponectin. High-resolution B-mode ultrasound was used to determine endothelium-dependent and -independent vasodilation. RESULTS Type 2 diabetic, liposdystrophic, and PCOS subjects were insulin resistant compared with control subjects (P = 0.001). Flow-mediated vasodilation was reduced in diabetic (3.4 +/- 1.3%) compared with control (7.3 +/- 1.1%) subjects but not in lipodystrophic (7.7 +/- 1.2%) or PCOS (9.9 +/- 0.7%) subjects (P = 0.005). Nitroglycerin-mediated vasodilation was attenuated in both diabetic (15.2 +/- 2.0%) and lipodystrophic (16.7 +/- 3.6%) subjects compared with healthy control (24.6 +/- 2.4%) and PCOS (23.2 +/- 1.8%) subjects (P = 0.019). Insulin resistance, free fatty acids, adiponectin, or C-reactive protein did not associate with vascular dysfunction. CONCLUSIONS Among these different types of patients with insulin resistance, we found abnormal endothelium-dependent vasodilation only in the patients with type 2 diabetes. We postulate that variations in the mechanism of insulin resistance may affect endothelial function differently than glucose homeostasis.
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Affiliation(s)
- Joshua A Beckman
- Cardiovascular Division, Brigham and Women's Hospital, 75 Francis St., Boston, MA 02115, USA.
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Donato AJ, Lesniewski LA, Delp MD. Ageing and exercise training alter adrenergic vasomotor responses of rat skeletal muscle arterioles. J Physiol 2006; 579:115-25. [PMID: 17082231 PMCID: PMC2075385 DOI: 10.1113/jphysiol.2006.120055] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
UNLABELLED Ageing is associated with increased leg vascular resistance and reductions in leg blood flow during rest and exercise, potentially predisposing older adults to a host of functional and cardiovascular complications. The purpose of these studies was to examine the effects and possible mechanisms of ageing and exercise training on arteriolar adrenergic vasoreactivity. Young and old male Fischer 344 rats were divided into young sedentary (YS), old sedentary (OS), young exercise-trained (YT) or old exercise-trained (OT) groups, where training consisted of chronic treadmill exercise. Isolated soleus (SOL) and gastrocnemius (GAS) muscle arterioles were studied in vitro. Responses to noradrenaline in endothelium-intact and endothelium-denuded arterioles, as well as during nitric oxide synthase (NOS) inhibition were determined. Vasodilator responses to isoproterenol and forskolin were also determined. RESULTS Noradrenaline-mediated vasoconstriction was increased in SOL arterioles with ageing, and exercise training in old rats attenuated alpha-adrenergic vasoconstriction in arterioles from both muscle types. Removal of the endothelium and NOS inhibition eliminated these ageing and training effects. Isoproterenol-mediated vasodilatation was impaired with ageing in SOL and GAS arterioles, and exercise training had little effect on this response. Forskolin-induced vasodilatation was not affected by age. The data demonstrate that ageing augments alpha-adrenergic vasoconstriction while exercise training attenuates this response, and both of these alterations are mediated through an endothelial alpha-receptor-NOS-signalling pathway. In contrast, ageing diminishes beta-receptor-mediated vasodilatation, but this impairment is specific to the smooth muscle. These studies indicate that alpha- and beta-adrenergic mechanisms may serve to increase systemic vascular resistance with ageing, and that the effects of exercise training on adrenergic vasomotor properties could contribute to the beneficial effects of exercise on cardiovascular disease.
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Affiliation(s)
- Anthony J Donato
- Department of Health and Kinisiology, Texas A and M University, College Station, TX 77843, USA
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De Galan BE, De Mol P, Wennekes L, Schouwenberg BJJ, Smits P. Preserved sensitivity to beta2-adrenergic receptor agonists in patients with type 1 diabetes mellitus and hypoglycemia unawareness. J Clin Endocrinol Metab 2006; 91:2878-81. [PMID: 16705070 DOI: 10.1210/jc.2006-0528] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND OBJECTIVE Use of beta(2)-adrenergic receptor agonists has been advocated for the treatment of hypoglycemia unawareness in type 1 diabetes. In vitro, however, hypoglycemia unawareness has been associated with reduced beta(2)-adrenergic sensitivity. Therefore, in vivo sensitivity to beta(2)-adrenergic receptor agonist stimulation was compared between type 1 diabetic patients with and without hypoglycemia unawareness and nondiabetic controls. METHODS Ten type 1 diabetic patients with hypoglycemia unawareness, 12 type 1 diabetic patients with intact hypoglycemic awareness, and 11 healthy controls were enrolled. beta(2)-Adrenergic sensitivity was determined by measuring the forearm vasodilator response to intraarterial infusion of salbutamol. Salbutamol was infused in six increasing doses ranging from 0.003 to 1.0 mug(1).min(-1).dl(-1). Forearm blood flow (FBF) was bilaterally measured by venous occlusion plethysmography. Diabetic patients received low-dose insulin before FBF measurements to ensure that experiments were carried out under normoglycemic conditions. RESULTS At baseline, FBF was 1.9 +/- 0.3 ml(1).min(-1).dl(-1) in controls, 2.3 +/- 0.4 ml(1).min(-1).dl(-1) in patients with intact awareness, and 1.4 +/- 0.1 ml(1).min(-1).dl(-1) in patients with hypoglycemia unawareness (P = 0.048 vs. aware patients). In response to salbutamol, FBF increased 9.1-fold in controls, 8.0-fold in patients with intact awareness, and 10.7-fold in patients with hypoglycemia unawareness (P = NS). Heart rate increased in all groups due to systemic spillover of salbutamol but appeared blunted, considering a greater fall in mean arterial pressure in patients with hypoglycemia unawareness. CONCLUSIONS Sensitivity to beta(2)-adrenergic receptor agonist stimulation is preserved in type 1 diabetic patients with hypoglycemia unawareness.
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Affiliation(s)
- Bastiaan E De Galan
- Department of General Internal Medicine 463, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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Van Guilder GP, Hoetzer GL, Dengel DR, Stauffer BL, DeSouza CA. Impaired endothelium-dependent vasodilation in normotensive and normoglycemic obese adult humans. J Cardiovasc Pharmacol 2006; 47:310-3. [PMID: 16495771 DOI: 10.1097/01.fjc.0000205097.29946.d3] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Acetylcholine (ACh)-mediated endothelium-dependent vasodilation has been shown to be impaired in obese adults. However, the mechanisms responsible for this impairment are not clear. We determined whether the blunted forearm vasodilator response to acetylcholine with obesity is due, at least in part, to reduced muscarinic receptor responsiveness. Twenty-eight sedentary middle-aged adults were studied: 14 normal weight (BMI, 23.6 +/- 0.5 kg/m) and 14 obese (32.2 +/- 0.9 kg/m). Forearm blood flow (FBF) was determined in response to intraarterial infusion of acetylcholine (8-128 microg/min) and sodium nitroprusside (SNP: 2.0-8.0 microg/min). Regardless of the dose, forearm blood flow responses to acetylcholine were 25% (P < 0.01) lower in the obese (from 4.2 +/- 0.3 to 12.0 +/- 0.8 mL/100 mL tissue/min) compared with normal weight (4.4 +/- 0.3 to 16.9 +/- 1.0 mL/100 mL tissue/min) adults. Of note, forearm blood flow responses to acetylcholine plateaued at doses higher than 32 microg/min in both groups, no further increase in forearm blood flow was observed at either 64 or 128 microg/min. EC50 for acetylcholine-stimulated vasodilation was not different between the obese (7.8 +/- 0.8 microg/min) and normal weight (7.8 +/- 0.6 microg/min) adults. There were no group differences in the vasodilator response to sodium nitroprusside. These results indicate that the obesity-related impairment in acetylcholine-mediated vasodilation in the human forearm is not due to reduced muscarinic receptor responsiveness or sensitivity.
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Affiliation(s)
- Gary P Van Guilder
- Integrative Vascular Biology Laboratory Department of Integrative Physiology, University of Colorado, Boulder, CO 80309, USA
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Walther G, Nottin S, Dauzat M, Obert P. Femoral and Axillary Ultrasound Blood Flow during Exercise. Med Sci Sports Exerc 2006; 38:1353-61. [PMID: 16826035 DOI: 10.1249/01.mss.0000227323.69588.f4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE To use Doppler ultrasound 1) to assess the relationship between exercise intensity and changes in femoral and axillary artery diameter, 2) to determine whether volume blood flow (BF) measured during early recovery accurately reflects exercise BF, and 3) to assess the influence of artery caliber and/or site as well as exercise intensity on BF measurement reproducibility. METHODS Thirteen healthy subjects (mean age 25.9+/-7.7 yr) performed progressive and maximal leg-extension (LE) and elbow-flexion (EF) exercises in the supine position. The duration of each stage was 150 s, followed by a 30-s recovery period. Arterial diameter and blood flow velocity were recorded simultaneously and continuously during the last 30 s of exercise as well as 30 s into recovery. RESULTS Arterial dilation was 3.5 and 6.5% at maximal effort in femoral and axillary arteries, respectively. A significant increase was observed for both arteries from workload 2 to peak exercise when arterial cross-sectional area was calculated. Blood flow velocity during the recovery period was significantly different from end-exercise values, depending on time and workload. The coefficients of variation of BF measurement during exercise were 7.1-12.1% and 6.4-9.5% in LE and EF, respectively. CONCLUSION This study showed that BF measurement with Doppler ultrasound during exercise is reproducible but requires measurement of arterial diameter at each workload. Measurements performed immediately after exercise cannot be used as a surrogate for blood flow velocity during exercise.
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Affiliation(s)
- Guillaume Walther
- Laboratory of Cardiovascular Adaptations to Exercise, Faculty of Sciences, Avignon, France
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Wray DW, Uberoi A, Lawrenson L, Richardson RS. Evidence of preserved endothelial function and vascular plasticity with age. Am J Physiol Heart Circ Physiol 2005; 290:H1271-7. [PMID: 16272199 DOI: 10.1152/ajpheart.00883.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We sought to identify the relationship between shear stimuli and flow-mediated vasodilation and to determine whether small muscle mass exercise training could provoke limb-specific improvements in endothelial function in older subjects. In five young (22 +/- 1 yr old) and six old (71 +/- 2 yr old) subjects, ultrasound Doppler measurements were taken in the arm (brachial artery) and leg (deep and superficial femoral arteries) after suprasystolic cuff occlusion with and without ischemic exercise to evaluate flow-mediated dilation (FMD) in both limbs. Older subjects were reevaluated after 6 wk of single-leg knee extensor exercise training. Before the training, a significant FMD was observed in the arm of young (3 +/- 1%) but not old (1 +/- 1%) subjects, whereas a significant leg FMD was observed in both groups (5 +/- 1% old vs. 3 +/- 1% young). However, arm vasodilation was similar between young and old when normalized for shear rate, and cuff occlusion with superimposed handgrip exercise provoked additional shear, which proportionately improved the FMD response in both groups. Exercise training significantly improved arm FMD (5 +/- 1%), whereas leg FMD was unchanged. However, ischemic handgrip exercise did not provoke additional arm vasodilation after training, which may indicate an age-related limit to shear-induced vasodilation. Together, these data demonstrate that vascular reactivity is dependent on limb and degree of shear stimuli, challenging the convention of diminished endothelial function typically associated with age. Likewise, exercise training improved arm vasodilation, indicating some preservation of vascular plasticity with age.
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Affiliation(s)
- D Walter Wray
- Physiology Division, Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0623, USA.
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