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Yang H, Chen Z, Hu X, Wei N, Li J, Wei Y, Chen Q. A Study on Vascular Regulators as Early Biomarkers of Hand Arm Vibration Syndrome. J Occup Environ Med 2023; 65:1070-1076. [PMID: 37696808 DOI: 10.1097/jom.0000000000002957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
OBJECTIVES Purposes of this study are to study the changes in expression of vascular regulators after vibration exposure and during the onset of vibration-induced white finger (VWF) and to screen for vascular regulatory factors that could be used as early biomarkers of HAVS. METHODS Using judgmental sampling from a Chinese factory, workers with VWF and hand-transmitted vibration exposure but without VWF were selected for research. Blood samples were taken from all subjects, and the levels of nine of the vascular regulators were measured using ELISA. RESULTS Receiver operating characteristic curve analysis was performed on nine vascular regulators to assess their diagnostic sensitivity for VWF with the following area under the curve results: PGI 2 = 0.861, ANP = 0.840. CONCLUSIONS Collectively, PGI 2 and ANP exhibited the most potential for the early diagnosis of HAVS.
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Affiliation(s)
- Hongyu Yang
- From the School of Public Health, Guangdong Pharmaceutical University, Guangzhou, China; and Guangdong Provincial Engineering Research Center of Public Health Detection and Assessment, Guangdong Pharmaceutical University, Guangzhou, China
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Shannon OM, Clifford T, Seals DR, Craighead DH, Rossman MJ. Nitric oxide, aging and aerobic exercise: Sedentary individuals to Master's athletes. Nitric Oxide 2022; 125-126:31-39. [PMID: 35705144 DOI: 10.1016/j.niox.2022.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 05/27/2022] [Accepted: 06/06/2022] [Indexed: 12/12/2022]
Abstract
Aging is associated with a decline in physiological function and exercise performance. These effects are mediated, at least in part, by an age-related decrease in the bioavailability of nitric oxide (NO), a ubiquitous gasotransmitter and regulator of myriad physiological processes. The decrease in NO bioavailability with aging is especially apparent in sedentary individuals, whereas older, physically active individuals maintain higher levels of NO with advancing age. Strategies which enhance NO bioavailability (including nutritional supplementation) have been proposed as a potential means of reducing the age-related decrease in physiological function and enhancing exercise performance and may be of interest to a range of older individuals including those taking part in competitive sport. In this brief review we discuss the effects of aging on physiological function and endurance exercise performance, and the potential role of changes in NO bioavailability in these processes. We also provide a summary of current evidence for dietary supplementation with substrates for NO production - including inorganic nitrate and nitrite, l-arginine and l-citrulline - for improving exercise capacity/performance in older adults. Additionally, we discuss the (limited) evidence on the effects of (poly)phenols and other dietary antioxidants on NO bioavailability in older individuals. Finally, we provide suggestions for future research.
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Affiliation(s)
- Oliver M Shannon
- Human Nutrition Research Centre, Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK.
| | - Tom Clifford
- School of Sport, Exercise and Health Science, Loughborough University, Loughborough, UK
| | - Douglas R Seals
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Daniel H Craighead
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Matthew J Rossman
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
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3
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Common Shared Pathogenic Aspects of Small Vessels in Heart and Brain Disease. Biomedicines 2022; 10:biomedicines10051009. [PMID: 35625746 PMCID: PMC9138783 DOI: 10.3390/biomedicines10051009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/21/2022] [Accepted: 04/26/2022] [Indexed: 12/24/2022] Open
Abstract
Small-vessel disease (SVD), also known as microvascular endothelial dysfunction, is a disorder with negative consequences for various organs such as the heart and brain. Impaired dilatation and constriction of small vessels in the heart lead to reduced blood flow and ischemia independently of coronary artery disease (CAD) and are associated with major cardiac events. SVD is usually a silent form of subcortical vascular burden in the brain with various clinical manifestations, such as silent-lacunar-ischemic events and confluent white-matter hyperintensities. Imaging techniques are the main help for clinicians to diagnose cardiac and brain SVD correctly. Markers of inflammation, such as C-reactive protein, tumor-necrosis-factor α, and interleukin 6, provide insight into the disease and markers that negatively influence nitric-oxide bioavailability and promote oxidative stress. Unfortunately, the therapeutic approach against SVD is still not well-defined. In the last decades, various antioxidants, oxidative stress inhibitors, and superoxide scavengers have been the target of extensive investigations due to their potential therapeutic effect, but with unsatisfactory results. In clinical practice, traditional anti-ischemic and risk-reduction therapies for CAD are currently in use for SVD treatment.
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Small Vessel Disease: Ancient Description, Novel Biomarkers. Int J Mol Sci 2022; 23:ijms23073508. [PMID: 35408867 PMCID: PMC8998274 DOI: 10.3390/ijms23073508] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/20/2022] [Accepted: 03/21/2022] [Indexed: 12/22/2022] Open
Abstract
Small vessel disease (SVD) is one of the most frequent pathological conditions which lead to dementia. Biochemical and neuroimaging might help correctly identify the clinical diagnosis of this relevant brain disease. The microvascular alterations which underlie SVD have common origins, similar cognitive outcomes, and common vascular risk factors. Nevertheless, the arteriolosclerosis process, which underlines SVD development, is based on different mechanisms, not all completely understood, which start from a chronic hypoperfusion state and pass through a chronic brain inflammatory condition, inducing a significant endothelium activation and a consequent tissue remodeling action. In a recent review, we focused on the pathophysiology of SVD, which is complex, involving genetic conditions and different co-morbidities (i.e., diabetes, chronic hypoxia condition, and obesity). Currently, many points still remain unclear and discordant. In this paper, we wanted to focus on new biomarkers, which can be the expression of the endothelial dysfunction, or of the oxidative damage, which could be employed as markers of disease progression or for future targets of therapies. Therefore, we described the altered response to the endothelium-derived nitric oxide-vasodilators (ENOV), prostacyclin, C-reactive proteins, and endothelium-derived hyperpolarizing factors (EDHF). At the same time, due to the concomitant endothelial activation and chronic neuroinflammatory status, we described hypoxia-endothelial-related markers, such as HIF 1 alpha, VEGFR2, and neuroglobin, and MMPs. We also described blood–brain barrier disruption biomarkers and imaging techniques, which can also describe perivascular spaces enlargement and dysfunction. More studies should be necessary, in order to implement these results and give them a clinical benefit.
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Begum MK, Konja D, Singh S, Chlopicki S, Wang Y. Endothelial SIRT1 as a Target for the Prevention of Arterial Aging: Promises and Challenges. J Cardiovasc Pharmacol 2021; 78:S63-S77. [PMID: 34840264 DOI: 10.1097/fjc.0000000000001154] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 09/25/2021] [Indexed: 12/15/2022]
Abstract
ABSTRACT SIRT1, a member of the sirtuin family of longevity regulators, possesses potent activities preventing vascular aging. The expression and function of SIRT1 in endothelial cells are downregulated with age, in turn causing early vascular aging and predisposing various vascular abnormalities. Overexpression of SIRT1 in the vascular endothelium prevents aging-associated endothelial dysfunction and senescence, thus the development of hypertension and atherosclerosis. Numerous efforts have been directed to increase SIRT1 signaling as a potential strategy for different aging-associated diseases. However, the complex mechanisms underlying the regulation of SIRT1 have posed a significant challenge toward the design of specific and effective therapeutics. This review aimed to provide a summary on the regulation and function of SIRT1 in the vascular endothelium and to discuss the different approaches targeting this molecule for the prevention and treatment of age-related cardiovascular and cerebrovascular diseases.
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Affiliation(s)
- Musammat Kulsuma Begum
- The State Key Laboratory of Pharmaceutical Biotechnology
- The Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong SAR, China
| | - Daniels Konja
- The State Key Laboratory of Pharmaceutical Biotechnology
- The Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong SAR, China
| | - Sandeep Singh
- The State Key Laboratory of Pharmaceutical Biotechnology
- The Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong SAR, China
| | - Stefan Chlopicki
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, Krakow, Poland; and
- Chair of Pharmacology, Jagiellonian University Medical College, Krakow, Poland
| | - Yu Wang
- The State Key Laboratory of Pharmaceutical Biotechnology
- The Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong SAR, China
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Abstract
UNLABELLED Exercise is associated with higher cognitive function and is a promising intervention to reduce the risk of dementia. With advancing age, there are changes in the vasculature that have important clinical implications for brain health and cognition. Primary aging and vascular risk factors are associated with increases in arterial stiffness and pulse pressure, and reductions in peripheral vascular function. OBJECTIVE The purpose is to discuss the epidemiological, observational, and mechanistic evidence regarding the link between age-related changes in vascular health and brain health. METHODS We performed a literature review and integrated with our published data. RESULTS Epidemiological evidence suggests a link between age-related increases in arterial stiffness and lower cognitive function, which may be mediated by cerebral vascular function, including cerebral vasoreactivity and cerebral pulsatility. Age-associated impairments in central arterial stiffness and peripheral vascular function have been attenuated or reversed through lifestyle behaviors such as exercise. Greater volumes of habitual exercise and higher cardiorespiratory fitness are associated with beneficial effects on both peripheral vascular health and cognition. Yet, the extent to which exercise directly influences cerebral vascular function and brain health, as well as the associated mechanisms remains unclear. CONCLUSION Although there is evidence that exercise positively impacts cerebral vascular function, more research is necessary in humans to optimize experimental protocols and address methodological limitations and physiological considerations. Understanding the impact of exercise on cerebral vascular function is important for understanding the association between exercise and brain health and may inform future intervention studies that seek to improve cognition.
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Pearson AG, Miller KB, Corkery AT, Eisenmann NA, Howery AJ, Carl AE, Eldridge MW, Barnes JN. Impact of age and cyclooxygenase inhibition on the hemodynamic response to acute cognitive challenges. Am J Physiol Regul Integr Comp Physiol 2021; 321:R208-R219. [PMID: 34161746 DOI: 10.1152/ajpregu.00048.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Structural and functional changes in the cerebral vasculature occur with advancing age, which may lead to impaired neurovascular coupling (NVC) and cognitive decline. Cyclooxygenase (COX) inhibition abolishes age-related differences in cerebrovascular reactivity, but it is unclear if COX inhibition impacts NVC. The purpose of this study was to examine the influence of aging on NVC before and after COX inhibition. Twenty-three young (age = 25 ± 4 yr) and 21 older (age = 64 ± 5 yr) adults completed two levels of difficulty of the Stroop and n-back tests before and after COX inhibition. Middle cerebral artery blood velocity (MCAv) was measured using transcranial Doppler ultrasound and mean arterial blood pressure (MAP) was measured using a finger cuff. Hemodynamic variables were measured at rest and in response to cognitive challenges. During the Stroop test, older adults demonstrated a greater increase in MCAv (young: 2.2 ± 6.8% vs. older: 5.9 ± 5.8%; P = 0.030) and MAP (young: 2.0 ± 4.9% vs. older: 4.8 ± 4.9%; P = 0.036) compared with young adults. There were no age-related differences during the n-back test. COX inhibition reduced MCAv by 30% in young and 26% in older adults (P < 0.001 for both). During COX inhibition, there were no age-related differences in the percent change in MCAv or MAP in response to the cognitive tests. Our results show that older adults require greater increases in MCAv and MAP during a test of executive function compared with young adults and that any age-related differences in NVC were abolished during COX inhibition. Collectively, this suggests that aging is associated with greater NVC necessary to accomplish a cognitive task.
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Affiliation(s)
- Andrew G Pearson
- Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kathleen B Miller
- Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Adam T Corkery
- Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Nicole A Eisenmann
- Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Anna J Howery
- Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Alexandra E Carl
- Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Marlowe W Eldridge
- Division of Critical Care, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.,John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Jill N Barnes
- Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin.,Division of Geriatrics and Gerontology, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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8
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Moretti R, Giuffré M, Caruso P, Gazzin S, Tiribelli C. Homocysteine in Neurology: A Possible Contributing Factor to Small Vessel Disease. Int J Mol Sci 2021; 22:ijms22042051. [PMID: 33669577 PMCID: PMC7922986 DOI: 10.3390/ijms22042051] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 12/19/2022] Open
Abstract
Homocysteine (Hcy) is a sulfur-containing amino acid generated during methionine metabolism, accumulation of which may be caused by genetic defects or the deficit of vitamin B12 and folate. A serum level greater than 15 micro-mols/L is defined as hyperhomocysteinemia (HHcy). Hcy has many roles, the most important being the active participation in the transmethylation reactions, fundamental for the brain. Many studies focused on the role of homocysteine accumulation in vascular or degenerative neurological diseases, but the results are still undefined. More is known in cardiovascular disease. HHcy is a determinant for the development and progression of inflammation, atherosclerotic plaque formation, endothelium, arteriolar damage, smooth muscle cell proliferation, and altered-oxidative stress response. Conversely, few studies focused on the relationship between HHcy and small vessel disease (SVD), despite the evidence that mice with HHcy showed a significant end-feet disruption of astrocytes with a diffuse SVD. A severe reduction of vascular aquaporin-4-water channels, lower levels of high-functioning potassium channels, and higher metalloproteinases are also observed. HHcy modulates the N-homocysteinylation process, promoting a pro-coagulative state and damage of the cellular protein integrity. This altered process could be directly involved in the altered endothelium activation, typical of SVD and protein quality, inhibiting the ubiquitin-proteasome system control. HHcy also promotes a constant enhancement of microglia activation, inducing the sustained pro-inflammatory status observed in SVD. This review article addresses the possible role of HHcy in small-vessel disease and understands its pathogenic impact.
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Affiliation(s)
- Rita Moretti
- Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy; (M.G.); (P.C.)
- Correspondence:
| | - Mauro Giuffré
- Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy; (M.G.); (P.C.)
| | - Paola Caruso
- Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy; (M.G.); (P.C.)
| | - Silvia Gazzin
- Italian Liver Foundation, AREA SCIENCE PARK, 34149 Trieste, Italy; (S.G.); (C.T.)
| | - Claudio Tiribelli
- Italian Liver Foundation, AREA SCIENCE PARK, 34149 Trieste, Italy; (S.G.); (C.T.)
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Balasubramanian P, Kiss T, Tarantini S, Nyúl-Tóth Á, Ahire C, Yabluchanskiy A, Csipo T, Lipecz A, Tabak A, Institoris A, Csiszar A, Ungvari Z. Obesity-induced cognitive impairment in older adults: a microvascular perspective. Am J Physiol Heart Circ Physiol 2021; 320:H740-H761. [PMID: 33337961 PMCID: PMC8091942 DOI: 10.1152/ajpheart.00736.2020] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/30/2020] [Accepted: 12/12/2020] [Indexed: 02/07/2023]
Abstract
Over two-thirds of individuals aged 65 and older are obese or overweight in the United States. Epidemiological data show an association between the degree of adiposity and cognitive dysfunction in the elderly. In this review, the pathophysiological roles of microvascular mechanisms, including impaired endothelial function and neurovascular coupling responses, microvascular rarefaction, and blood-brain barrier disruption in the genesis of cognitive impairment in geriatric obesity are considered. The potential contribution of adipose-derived factors and fundamental cellular and molecular mechanisms of senescence to exacerbated obesity-induced cerebromicrovascular impairment and cognitive decline in aging are discussed.
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Affiliation(s)
- Priya Balasubramanian
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tamas Kiss
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Health Promotion Sciences, the Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Ádám Nyúl-Tóth
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- International Training Program in Geroscience, Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Chetan Ahire
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Andriy Yabluchanskiy
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tamas Csipo
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Agnes Lipecz
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Adam Tabak
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Internal Medicine and Oncology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- Department of Epidemiology and Public Health, University College London, London, United Kingdom
| | - Adam Institoris
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Zoltan Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Health Promotion Sciences, the Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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Izzo C, Vitillo P, Di Pietro P, Visco V, Strianese A, Virtuoso N, Ciccarelli M, Galasso G, Carrizzo A, Vecchione C. The Role of Oxidative Stress in Cardiovascular Aging and Cardiovascular Diseases. Life (Basel) 2021; 11:60. [PMID: 33467601 PMCID: PMC7829951 DOI: 10.3390/life11010060] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 12/12/2022] Open
Abstract
Aging can be seen as process characterized by accumulation of oxidative stress induced damage. Oxidative stress derives from different endogenous and exogenous processes, all of which ultimately lead to progressive loss in tissue and organ structure and functions. The oxidative stress theory of aging expresses itself in age-related diseases. Aging is in fact a primary risk factor for many diseases and in particular for cardiovascular diseases and its derived morbidity and mortality. Here we highlight the role of oxidative stress in age-related cardiovascular aging and diseases. We take into consideration the molecular mechanisms, the structural and functional alterations, and the diseases accompanied to the cardiovascular aging process.
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Affiliation(s)
- Carmine Izzo
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Paolo Vitillo
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Paola Di Pietro
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Valeria Visco
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Andrea Strianese
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Nicola Virtuoso
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Michele Ciccarelli
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Gennaro Galasso
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
| | - Albino Carrizzo
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
- Department of Angio-Cardio-Neurology, Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Isernia, Italy
| | - Carmine Vecchione
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, 84081 Salerno, Italy; (C.I.); (P.V.); (P.D.P.); (V.V.); (A.S.); (N.V.); (M.C.); (G.G.); (A.C.)
- Department of Angio-Cardio-Neurology, Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Isernia, Italy
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11
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An Iatrogenic Model of Brain Small-Vessel Disease: Post-Radiation Encephalopathy. Int J Mol Sci 2020; 21:ijms21186506. [PMID: 32899565 PMCID: PMC7555594 DOI: 10.3390/ijms21186506] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/27/2020] [Accepted: 09/01/2020] [Indexed: 12/21/2022] Open
Abstract
We studied 114 primitive cerebral neoplasia, that were surgically treated, and underwent radiotherapy (RT), and compared their results to those obtained by 190 patients diagnosed with subcortical vascular dementia (sVAD). Patients with any form of primitive cerebral neoplasia underwent whole-brain radiotherapy. All the tumor patients had regional field partial brain RT, which encompassed each tumor, with an average margin of 2.6 cm from the initial target tumor volume. We observed in our patients who have been exposed to a higher dose of RT (30–65 Gy) a cognitive and behavior decline similar to that observed in sVAD, with the frontal dysexecutive syndrome, apathy, and gait alterations, but with a more rapid onset and with an overwhelming effect. Multiple mechanisms are likely to be involved in radiation-induced cognitive impairment. The active site of RT brain damage is the white matter areas, particularly the internal capsule, basal ganglia, caudate, hippocampus, and subventricular zone. In all cases, radiation damage inside the brain mainly focuses on the cortical–subcortical frontal loops, which integrate and process the flow of information from the cortical areas, where executive functions are “elaborated” and prepared, towards the thalamus, subthalamus, and cerebellum, where they are continuously refined and executed. The active mechanisms that RT drives are similar to those observed in cerebral small vessel disease (SVD), leading to sVAD. The RT’s primary targets, outside the tumor mass, are the blood–brain barrier (BBB), the small vessels, and putative mechanisms that can be taken into account are oxidative stress and neuro-inflammation, strongly associated with the alteration of NMDA receptor subunit composition.
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Junejo RT, Ray CJ, Marshall JM. Prostaglandin contribution to postexercise hyperemia is dependent on tissue oxygenation during rhythmic and isometric contractions. Physiol Rep 2020; 8:e14471. [PMID: 32562377 PMCID: PMC7305242 DOI: 10.14814/phy2.14471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/27/2020] [Accepted: 05/10/2020] [Indexed: 12/21/2022] Open
Abstract
The role of prostaglandins (PGs) in exercise hyperemia is controversial. We tested their contributions in moderate intensity forearm exercise, whether their release is oxygen (O2)‐dependent or affected by aging. A total of 12 young (21 ± 1 years) and 11 older (66 ± 2 years) recreationally active men performed rhythmic and isometric handgrip contractions at 60% maximum voluntary contraction for 3 min during air breathing after placebo, after cyclooxygenase (COX) inhibition with aspirin, while breathing 40% O2 and during their combination (aspirin + 40% O2). Forearm blood flow (FBF) was recorded with venous occlusion plethysmography (forearm vascular conductance (FVC): FBF/mean arterial pressure). Venous efflux of PGI2 and PGE2 were assessed by immunoassay. Postcontraction increases in FVC were similar for rhythmic and isometric contractions in young and older men, and accompanied by similar increases in efflux of PGI2 and PGE2. Aspirin attenuated the efflux of PGI2 by 75%–85%, PGE2 by 50%–70%, (p < .05 within group; p > .05 young versus. older), and postcontraction increases in FVC by 22%–27% and 17%–21% in young and older men, respectively (p < .05 within group and young versus. older). In both age groups, 40% O2 and aspirin + 40% O2 caused similar inhibition of the increases in FVC and efflux of PGs as aspirin alone (p < .05 within group). These results indicate that PGs make substantial contributions to the postcontraction hyperemia of rhythmic and isometric contractions at moderate intensities in recreationally active young and older men. Given PGI2 is mainly released by endothelium and PGE2 by muscle fibers, we propose PG generation is dependent on the contraction‐induced falls in O2 at these sites.
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Affiliation(s)
- Rehan T Junejo
- School of Sport, Exercise & Rehabilitation Sciences, College of Life & Environmental Sciences, Birmingham, UK
| | - Clare J Ray
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Janice M Marshall
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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13
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Moretti R, Caruso P. Small Vessel Disease-Related Dementia: An Invalid Neurovascular Coupling? Int J Mol Sci 2020; 21:E1095. [PMID: 32046035 PMCID: PMC7036993 DOI: 10.3390/ijms21031095] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/04/2020] [Accepted: 02/04/2020] [Indexed: 12/18/2022] Open
Abstract
The arteriosclerosis-dependent alteration of brain perfusion is one of the major determinants in small vessel disease, since small vessels have a pivotal role in the brain's autoregulation. Nevertheless, as far as we know, endothelium distress can potentiate the flow dysregulation and lead to subcortical vascular dementia that is related to small vessel disease (SVD), also being defined as subcortical vascular dementia (sVAD), as well as microglia activation, chronic hypoxia and hypoperfusion, vessel-tone dysregulation, altered astrocytes, and pericytes functioning blood-brain barrier disruption. The molecular basis of this pathology remains controversial. The apparent consequence (or a first event, too) is the macroscopic alteration of the neurovascular coupling. Here, we examined the possible mechanisms that lead a healthy aging process towards subcortical dementia. We remarked that SVD and white matter abnormalities related to age could be accelerated and potentiated by different vascular risk factors. Vascular function changes can be heavily influenced by genetic and epigenetic factors, which are, to the best of our knowledge, mostly unknown. Metabolic demands, active neurovascular coupling, correct glymphatic process, and adequate oxidative and inflammatory responses could be bulwarks in defense of the correct aging process; their impairments lead to a potentially catastrophic and non-reversible condition.
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Affiliation(s)
- Rita Moretti
- Neurology Clinic, Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy;
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14
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Limberg JK, Casey DP, Trinity JD, Nicholson WT, Wray DW, Tschakovsky ME, Green DJ, Hellsten Y, Fadel PJ, Joyner MJ, Padilla J. Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology. Am J Physiol Heart Circ Physiol 2019; 318:H301-H325. [PMID: 31886718 DOI: 10.1152/ajpheart.00649.2019] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,François M. Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | | | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia, Australia
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | | | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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15
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Gliemann L, Vestergaard Hansen C, Rytter N, Hellsten Y. Regulation of skeletal muscle blood flow during exercise. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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16
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Stanhewicz AE, Wenner MM, Stachenfeld NS. Sex differences in endothelial function important to vascular health and overall cardiovascular disease risk across the lifespan. Am J Physiol Heart Circ Physiol 2018; 315:H1569-H1588. [PMID: 30216121 PMCID: PMC6734083 DOI: 10.1152/ajpheart.00396.2018] [Citation(s) in RCA: 196] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/22/2018] [Accepted: 08/31/2018] [Indexed: 02/07/2023]
Abstract
Diseases of the cardiovascular system are the leading cause of morbidity and mortality in men and women in developed countries, and cardiovascular disease (CVD) is becoming more prevalent in developing countries. The prevalence of atherosclerotic CVD in men is greater than in women until menopause, when the prevalence of CVD increases in women until it exceeds that of men. Endothelial function is a barometer of vascular health and a predictor of atherosclerosis that may provide insights into sex differences in CVD as well as how and why the CVD risk drastically changes with menopause. Studies of sex differences in endothelial function are conflicting, with some studies showing earlier decrements in endothelial function in men compared with women, whereas others show similar age-related declines between the sexes. Because the increase in CVD risk coincides with menopause, it is generally thought that female hormones, estrogens in particular, are cardioprotective. Moreover, it is often proposed that androgens are detrimental. In truth, the relationships are more complex. This review first addresses female and male sex hormones and their receptors and how these interact with the cardiovascular system, particularly the endothelium, in healthy young women and men. Second, we address sex differences in sex steroid receptor-independent mechanisms controlling endothelial function, focusing on vascular endothelin and the renin-angiotensin systems, in healthy young women and men. Finally, we discuss sex differences in age-associated endothelial dysfunction, focusing on the role of attenuated circulating sex hormones in these effects.
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Affiliation(s)
- Anna E Stanhewicz
- Department of Kinesiology, Pennsylvania State University , University Park, Pennsylvania
| | - Megan M Wenner
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Nina S Stachenfeld
- The John B. Pierce Laboratory, New Haven, Connecticut
- Department of Obstetrics, Gynecology and Reproductive Sciences and Yale School of Public Health, Yale School of Medicine, New Haven, Connecticut
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17
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Izzo C, Carrizzo A, Alfano A, Virtuoso N, Capunzo M, Calabrese M, De Simone E, Sciarretta S, Frati G, Oliveti M, Damato A, Ambrosio M, De Caro F, Remondelli P, Vecchione C. The Impact of Aging on Cardio and Cerebrovascular Diseases. Int J Mol Sci 2018; 19:E481. [PMID: 29415476 PMCID: PMC5855703 DOI: 10.3390/ijms19020481] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 01/29/2018] [Accepted: 02/01/2018] [Indexed: 01/03/2023] Open
Abstract
A growing number of evidences report that aging represents the major risk factor for the development of cardio and cerebrovascular diseases. Understanding Aging from a genetic, biochemical and physiological point of view could be helpful to design a better medical approach and to elaborate the best therapeutic strategy to adopt, without neglecting all the risk factors associated with advanced age. Of course, the better way should always be understanding risk-to-benefit ratio, maintenance of independence and reduction of symptoms. Although improvements in treatment of cardiovascular diseases in the elderly population have increased the survival rate, several studies are needed to understand the best management option to improve therapeutic outcomes. The aim of this review is to give a 360° panorama on what goes on in the fragile ecosystem of elderly, why it happens and what we can do, right now, with the tools at our disposal to slow down aging, until new discoveries on aging, cardio and cerebrovascular diseases are at hand.
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Affiliation(s)
- Carmine Izzo
- Departement of Medicine and Surgery, University of Salerno, 84081 Salerno, Italy; (C.I.); (M.C.); (M.O.); (F.D.C.); (P.R.)
| | - Albino Carrizzo
- Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Italy; (A.C.); (S.S.); (G.F.); (A.D.); (M.A.)
| | - Antonia Alfano
- Heart Department, A.O.U. “San Giovanni di Dio e Ruggi d’Aragona”, 84131 Salerno, Italy; (A.A.); (E.D.S.)
| | - Nicola Virtuoso
- Department of Cardiovascular Medicine, A.O.U. Federico II, 80131 Naples, Italy;
| | - Mario Capunzo
- Departement of Medicine and Surgery, University of Salerno, 84081 Salerno, Italy; (C.I.); (M.C.); (M.O.); (F.D.C.); (P.R.)
| | - Mariaconsiglia Calabrese
- Rehabilitation Department, A.O.U. “San Giovanni di Dio e Ruggi d’Aragona”, 84131 Salerno, Italy;
| | - Eros De Simone
- Heart Department, A.O.U. “San Giovanni di Dio e Ruggi d’Aragona”, 84131 Salerno, Italy; (A.A.); (E.D.S.)
| | - Sebastiano Sciarretta
- Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Italy; (A.C.); (S.S.); (G.F.); (A.D.); (M.A.)
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Polo Pontino, 04100 Latina, Italy
| | - Giacomo Frati
- Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Italy; (A.C.); (S.S.); (G.F.); (A.D.); (M.A.)
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Polo Pontino, 04100 Latina, Italy
| | - Marco Oliveti
- Departement of Medicine and Surgery, University of Salerno, 84081 Salerno, Italy; (C.I.); (M.C.); (M.O.); (F.D.C.); (P.R.)
| | - Antonio Damato
- Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Italy; (A.C.); (S.S.); (G.F.); (A.D.); (M.A.)
| | - Mariateresa Ambrosio
- Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Italy; (A.C.); (S.S.); (G.F.); (A.D.); (M.A.)
| | - Francesco De Caro
- Departement of Medicine and Surgery, University of Salerno, 84081 Salerno, Italy; (C.I.); (M.C.); (M.O.); (F.D.C.); (P.R.)
| | - Paolo Remondelli
- Departement of Medicine and Surgery, University of Salerno, 84081 Salerno, Italy; (C.I.); (M.C.); (M.O.); (F.D.C.); (P.R.)
| | - Carmine Vecchione
- Departement of Medicine and Surgery, University of Salerno, 84081 Salerno, Italy; (C.I.); (M.C.); (M.O.); (F.D.C.); (P.R.)
- Vascular Physiopathology Unit, IRCCS Neuromed, 86077 Pozzilli, Italy; (A.C.); (S.S.); (G.F.); (A.D.); (M.A.)
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18
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Characterisation of the vasodilation effects of DHA and EPA, n-3 PUFAs (fish oils), in rat aorta and mesenteric resistance arteries. PLoS One 2018; 13:e0192484. [PMID: 29394279 PMCID: PMC5796719 DOI: 10.1371/journal.pone.0192484] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/24/2018] [Indexed: 02/07/2023] Open
Abstract
Background and purpose Increasing evidence suggests that the omega-3 polyunsaturated acids (n-3 PUFA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are beneficial to cardiovascular health, promoting relaxation of vascular smooth muscle cells and vasodilation. Numerous studies have attempted to study these responses, but to date there has not been a systematic characterisation of both DHA and EPA mediated vasodilation in conduit and resistance arteries. Therefore, we aimed to fully characterise the n-3 PUFA-induced vasodilation pathways in rat aorta and mesenteric artery. Methods Wire myography was used to measure the vasomotor responses of freshly dissected rat mesenteric artery and aorta. Arteries were pre-constricted with U46619 and cumulative concentrations of either DHA or EPA (10 nM-30 μM) were added. The mechanisms by which n-3 PUFA relaxed arteries were investigated using inhibitors of vasodilator pathways, which include: nitric oxide synthase (NOS; L-NAME), cycloxygenase (COX; indomethacin), cytochrome P450 epoxygenase (CYP450; clotrimazole); and calcium-activated potassium channels (KCa), SKCa (apamin), IKCa (TRAM-34) and BKCa (paxilline). Results Both DHA- and EPA-induced relaxations were partially inhibited following endothelium removal in rat mesenteric arteries. Similarly, in aorta EPA-induced relaxation was partially suppressed due to endothelium removal. CYP450 also contributed to EPA-induced relaxation in mesenteric artery. Inhibition of IKCa partially attenuated DHA-induced relaxation in aorta and mesenteric artery along with EPA-induced relaxation in mesenteric artery. Furthermore, this inhibition of DHA- and EPA-induced relaxation was increased following the additional blockade of BKCa in these arteries. Conclusions This study provides evidence of heterogeneity in the vasodilation mechanisms of DHA and EPA in different vascular beds. Our data also demonstrates that endothelium removal has little effect on relaxations produced by either PUFA. We demonstrate IKCa and BKCa are involved in DHA-induced relaxation in rat aorta and mesenteric artery; and EPA-induced relaxation in rat mesenteric artery only. CYP450 derived metabolites of EPA may also be involved in BKCa dependent relaxation. To our knowledge this is the first study indicating the involvement of IKCa in n-3 PUFA mediated relaxation.
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19
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Mistriotis P, Andreadis ST. Vascular aging: Molecular mechanisms and potential treatments for vascular rejuvenation. Ageing Res Rev 2017; 37:94-116. [PMID: 28579130 DOI: 10.1016/j.arr.2017.05.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 05/22/2017] [Accepted: 05/25/2017] [Indexed: 12/14/2022]
Abstract
Aging is the main risk factor contributing to vascular dysfunction and the progression of vascular diseases. In this review, we discuss the causes and mechanisms of vascular aging at the tissue and cellular level. We focus on Endothelial Cell (EC) and Smooth Muscle Cell (SMC) aging due to their critical role in mediating the defective vascular phenotype. We elaborate on two categories that contribute to cellular dysfunction: cell extrinsic and intrinsic factors. Extrinsic factors reflect systemic or environmental changes which alter EC and SMC homeostasis compromising vascular function. Intrinsic factors induce EC and SMC transformation resulting in cellular senescence. Replenishing or rejuvenating the aged/dysfunctional vascular cells is critical to the effective repair of the vasculature. As such, this review also elaborates on recent findings which indicate that stem cell and gene therapies may restore the impaired vascular cell function, reverse vascular aging, and prolong lifespan.
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Affiliation(s)
- Panagiotis Mistriotis
- Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Amherst, NY 14260-4200, USA
| | - Stelios T Andreadis
- Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Amherst, NY 14260-4200, USA; Department of Biomedical Engineering, University at Buffalo, The State University of New York, Amherst, NY 14260-4200, USA; Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY 14203, USA.
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20
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Kenney WL. Edward F. Adolph Distinguished Lecture: Skin-deep insights into vascular aging. J Appl Physiol (1985) 2017; 123:1024-1038. [PMID: 28729391 DOI: 10.1152/japplphysiol.00589.2017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 11/22/2022] Open
Abstract
The skin is an accessible model circulation for studying vascular function and dysfunction across the lifespan. Age-related changes, as well as those associated with disease progression, often appear first in the cutaneous circulation. Furthermore, impaired vascular signaling and attendant endothelial dysfunction, the earliest indicators of cardiovascular pathogenesis, occur in a similar fashion across multiple tissue beds throughout the body, including the skin. Because microvascular dysfunction is a better predictor of long-term outcomes and adverse cardiovascular events than is large vessel disease, an understanding of age-associated changes in the control of the human cutaneous microcirculation is important. This review focuses on 1) the merits of using skin-specific methods and techniques to study vascular function, 2) microvascular changes in aged skin (in particular, the role of the endothelial-derived dilator nitric oxide), and 3) the impact of aging on heat-induced changes in skin vasodilation. While skin blood flow is controlled by multiple, often redundant, mechanisms, our laboratory has used a variety of distinct thermal provocations of this model circulation to isolate specific age-associated changes in vascular function. Skin-specific approaches and techniques, such as intradermal microdialysis coupled with laser-Doppler flowmetry (in vivo) and biochemical analyses of skin biopsy samples (in vitro), have allowed for the targeted pharmacodissection of the mechanistic pathways controlling skin vasoreactivity and study of the impact of aging and disease states. Aged skin has an attenuated ability to vasodilate in response to warm stimuli and to vasoconstrict in response to cold stimuli.
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Affiliation(s)
- W Larry Kenney
- Department of Kinesiology and Intercollege Graduate Program in Physiology, Noll Laboratory, The Pennsylvania State University, University Park, Pennsylvania
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21
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Cai W, Zhang K, Li P, Zhu L, Xu J, Yang B, Hu X, Lu Z, Chen J. Dysfunction of the neurovascular unit in ischemic stroke and neurodegenerative diseases: An aging effect. Ageing Res Rev 2017; 34:77-87. [PMID: 27697546 PMCID: PMC5384332 DOI: 10.1016/j.arr.2016.09.006] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/15/2016] [Accepted: 09/26/2016] [Indexed: 12/23/2022]
Abstract
Current understanding on the mechanisms of brain injury and neurodegeneration highlights an appreciation of multicellular interactions within the neurovascular unit (NVU), which include the evolution of blood-brain barrier (BBB) damage, neuronal cell death or degeneration, glial reaction, and immune cell infiltration. Aging is an important factor that influences the integrity of the NVU. The age-related physiological or pathological changes in the cellular components of the NVU have been shown to increase the vulnerability of the NVU to ischemia/reperfusion injury or neurodegeneration, and to result in deteriorated brain damage. This review describes the impacts of aging on each NVU component and discusses the mechanisms by which aging increases NVU sensitivity to stroke and neurodegenerative diseases. Prophylactic or therapeutic perspectives that may delay or diminish aging and thus prevent the incidence of these neurological disorders will also be reviewed.
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Affiliation(s)
- Wei Cai
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA; Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, 510630, China; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Kai Zhang
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Peiying Li
- Department of Anesthesiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ling Zhu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA; Department of Anesthesiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jing Xu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Boyu Yang
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Xiaoming Hu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Zhengqi Lu
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, 510630, China.
| | - Jun Chen
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA; Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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22
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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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Gliemann L, Nyberg M, Hellsten Y. Effects of exercise training and resveratrol on vascular health in aging. Free Radic Biol Med 2016; 98:165-176. [PMID: 27085843 DOI: 10.1016/j.freeradbiomed.2016.03.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/16/2016] [Accepted: 03/30/2016] [Indexed: 01/06/2023]
Abstract
Cardiovascular disease is a leading cause of death in the western world with aging being one of the strongest predictors of cardiovascular events. Aging is associated with impaired vascular function due to endothelial dysfunction and altered redox balance, partly caused by an increased formation of reactive oxygen species combined with a reduction in the endogenous antioxidant capacity. The consequence of these alterations is a reduced bioavailability of nitric oxide (NO) with implications for aspects such as control of vascular tone and low grade inflammation. However, it is not only aging per se but also the accumulative influence of physical inactivity and other life-style factors, which negatively affect the vascular system. Regular physical activity improves NO bioavailability, the redox balance and the plasma lipid profile and, at a functional level, reduces or even reverses a majority of the observed detrimental effects of aging on vascular function. The effects of aging and physical activity on vascular function are, in part, related to alterations in cellular signaling through sirtuin-1, AMPK and the estrogen receptor. The polyphenol resveratrol can activate these same pathways and has, in animals and in vitro models, been shown to act as a partial mimetic of physical activity. However, support for beneficial effects of resveratrol in human is weak and studies even show that resveratrol supplementation, similarly to supplementation with other antioxidants, can counteract the positive effects of physical activity. Regular physical activity remains the most effective way of maintaining and improving vascular health status and caution should be taken regarding potential interference of supplements on training adaptations.
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Affiliation(s)
- Lasse Gliemann
- Department of Nutrition, Exercise and Sports, Section for Integrative Physiology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
| | - Michael Nyberg
- Department of Nutrition, Exercise and Sports, Section for Integrative Physiology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, Section for Integrative Physiology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark.
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Nyberg M, Egelund J, Mandrup CM, Nielsen MB, Mogensen AS, Stallknecht B, Bangsbo J, Hellsten Y. Early Postmenopausal Phase Is Associated With Reduced Prostacyclin-Induced Vasodilation That Is Reversed by Exercise Training: The Copenhagen Women Study. Hypertension 2016; 68:1011-20. [PMID: 27550922 DOI: 10.1161/hypertensionaha.116.07866] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/28/2016] [Indexed: 12/21/2022]
Abstract
The postmenopausal phase is associated with an accelerated rate of rise in the prevalence of vascular dysfunction and hypertension; however, the mechanisms underlying these adverse vascular changes and whether exercise training can reverse the decline in vascular function remains unclear. We examined the function of the vascular prostanoid system in matched pre- and postmenopausal women before and after 12 weeks of exercise training. Twenty premenopausal and 16 early postmenopausal (3.1±0.5 [mean±SE] years after final menstrual period) women only separated by 4 (50±0 versus 54±1) years of age were included. Before the training period, the vasodilator response to intra-arterial infusion of either the prostacyclin analog epoprostenol or acetylcholine was lower (≈13%-41%; P<0.05) in the postmenopausal compared with the premenopausal women. Acetylcholine infusion induced a similar release of prostacyclin (6-keto prostaglandin F1a). To elucidate the role of vasoconstrictor prostanoids, acetylcholine infusion was combined with the cyclooxygenase inhibitor ketorolac and here the vascular response to acetylcholine was reduced to a similar extent in pre- and postmenopausal women. Exercise training increased (P<0.05) the vasodilator response to epoprostenol (≈100%-150%) and acetylcholine (≈100%-120%) infusion in the postmenopausal group. These findings demonstrate that the early postmenopausal phase is associated with a marked reduction in vascular function. Despite of a reduced sensitivity to prostacyclin, the overall balance between vasodilator and vasoconstrictor prostanoids does not seem to be altered. Exercise training can reverse the decline in vascular sensitivity to epoprostenol and acetylcholine, suggesting that beneficial vascular adaptations with exercise training are preserved in recent postmenopausal women.
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Affiliation(s)
- Michael Nyberg
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
| | - Jon Egelund
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
| | - Camilla M Mandrup
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
| | - Mads B Nielsen
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
| | - Alexander S Mogensen
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
| | - Bente Stallknecht
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
| | - Jens Bangsbo
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
| | - Ylva Hellsten
- From the Department of Nutrition, Exercise and Sports (M.N., J.E., M.B.N., A.S.M., J.B., Y.H.) and Department of Biomedical Sciences (C.M.M., B.S.), University of Copenhagen, Denmark
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Fujii N, Singh MS, Halili L, Boulay P, Sigal RJ, Kenny GP. Cutaneous vascular and sweating responses to intradermal administration of prostaglandin E1 and E2 in young and older adults: a role for nitric oxide? Am J Physiol Regul Integr Comp Physiol 2016; 310:R1064-72. [PMID: 27101302 DOI: 10.1152/ajpregu.00538.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/06/2016] [Indexed: 01/28/2023]
Abstract
Cyclooxygenase (COX) contributes to cutaneous vasodilation and sweating responses; however, the mechanisms underpinning these responses remain unknown. We hypothesized that prostaglandin E1 (PGE1) and E2 (PGE2) (COX-derived vasodilator products) directly mediate cutaneous vasodilation and sweating through nitric oxide synthase (NOS)-dependent mechanisms in young adults. Furthermore, we hypothesized that this response is diminished in older adults, since aging attenuates COX-dependent cutaneous vasodilation and sweating. In 9 young (22 ± 5 yr) and 10 older (61 ± 6 yr) adults, cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal forearm skin sites receiving incremental doses (0.05, 0.5, 5, 50, 500 μM each for 25 min) of PGE1 or PGE2 with and without coadministration of 10 mM N(ω)-nitro-l-arginine, a nonspecific NOS inhibitor. N(ω)-nitro-l-arginine attenuated PGE1-mediated increases in CVC at all concentrations in young adults, whereas it reduced PGE2-mediated increases in CVC at lower concentrations (0.05-0.5 μM) in older adults (all P < 0.05). However, the magnitude of the PGE1- and PGE2-mediated increases in CVC did not differ between groups (all P > 0.05). Neither PGE1 nor PGE2 increased sweat rate at any of the administered concentrations for either the young or older adults (all P > 0.05). We show that although cutaneous vascular responsiveness to PGE1 and PGE2 is similar between young and older adults, the cutaneous vasodilator response is partially mediated through NOS albeit via low-to-high concentrations of PGE1 in young adults and low concentrations of PGE2 in older adults, respectively. We also show that in both young and older adults, PGE1 and PGE2 do not increase sweat rate under normothermic conditions.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Maya Sarah Singh
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Lyra Halili
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Canada; and
| | - Ronald J Sigal
- Departments of Medicine, Cardiac Sciences and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada;
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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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Mokhtar SS, Vanhoutte PM, Leung SWS, Yusof MI, Wan Sulaiman WA, Mat Saad AZ, Suppian R, Rasool AHG. Endothelium dependent hyperpolarization-type relaxation compensates for attenuated nitric oxide-mediated responses in subcutaneous arteries of diabetic patients. Nitric Oxide 2016; 53:35-44. [DOI: 10.1016/j.niox.2015.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/23/2015] [Accepted: 12/28/2015] [Indexed: 01/17/2023]
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Abstract
Aerobic exercise training leads to cardiovascular changes that markedly increase aerobic power and lead to improved endurance performance. The functionally most important adaptation is the improvement in maximal cardiac output which is the result of an enlargement in cardiac dimension, improved contractility, and an increase in blood volume, allowing for greater filling of the ventricles and a consequent larger stroke volume. In parallel with the greater maximal cardiac output, the perfusion capacity of the muscle is increased, permitting for greater oxygen delivery. To accommodate the higher aerobic demands and perfusion levels, arteries, arterioles, and capillaries adapt in structure and number. The diameters of the larger conduit and resistance arteries are increased minimizing resistance to flow as the cardiac output is distributed in the body and the wall thickness of the conduit and resistance arteries is reduced, a factor contributing to increased arterial compliance. Endurance training may also induce alterations in the vasodilator capacity, although such adaptations are more pronounced in individuals with reduced vascular function. The microvascular net increases in size within the muscle allowing for an improved capacity for oxygen extraction by the muscle through a greater area for diffusion, a shorter diffusion distance, and a longer mean transit time for the erythrocyte to pass through the smallest blood vessels. The present article addresses the effect of endurance training on systemic and peripheral cardiovascular adaptations with a focus on humans, but also covers animal data.
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Affiliation(s)
- Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Michael Nyberg
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Donato AJ, Morgan RG, Walker AE, Lesniewski LA. Cellular and molecular biology of aging endothelial cells. J Mol Cell Cardiol 2015; 89:122-35. [PMID: 25655936 PMCID: PMC4522407 DOI: 10.1016/j.yjmcc.2015.01.021] [Citation(s) in RCA: 328] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 01/05/2015] [Accepted: 01/27/2015] [Indexed: 12/29/2022]
Abstract
Cardiovascular disease (CVD) is the leading cause of death in the United States and aging is a major risk factor for CVD development. One of the major age-related arterial phenotypes thought to be responsible for the development of CVD in older adults is endothelial dysfunction. Endothelial function is modulated by traditional CVD risk factors in young adults, but advancing age is independently associated with the development of vascular endothelial dysfunction. This endothelial dysfunction results from a reduction in nitric oxide bioavailability downstream of endothelial oxidative stress and inflammation that can be further modulated by traditional CVD risk factors in older adults. Greater endothelial oxidative stress with aging is a result of augmented production from the intracellular enzymes NADPH oxidase and uncoupled eNOS, as well as from mitochondrial respiration in the absence of appropriate increases in antioxidant defenses as regulated by relevant transcription factors, such as FOXO. Interestingly, it appears that NFkB, a critical inflammatory transcription factor, is sensitive to this age-related endothelial redox change and its activation induces transcription of pro-inflammatory cytokines that can further suppress endothelial function, thus creating a vicious feed-forward cycle. This review will discuss the two macro-mechanistic processes, oxidative stress and inflammation, that contribute to endothelial dysfunction with advancing age as well as the cellular and molecular events that lead to the vicious cycle of inflammation and oxidative stress in the aged endothelium. Other potential mediators of this pro-inflammatory endothelial phenotype are increases in immune or senescent cells in the vasculature. Of note, genomic instability, telomere dysfunction or DNA damage has been shown to trigger cell senescence via the p53/p21 pathway and result in increased inflammatory signaling in arteries from older adults. This review will discuss the current state of knowledge regarding the emerging concepts of senescence and genomic instability as mechanisms underlying oxidative stress and inflammation in the aged endothelium. Lastly, energy sensitive/stress resistance pathways (SIRT-1, AMPK, mTOR) are altered in endothelial cells and/or arteries with aging and these pathways may modulate endothelial function via key oxidative stress and inflammation-related transcription factors. This review will also discuss what is known about the role of "energy sensing" longevity pathways in modulating endothelial function with advancing age. With the growing population of older adults, elucidating the cellular and molecular mechanisms of endothelial dysfunction with age is critical to establishing appropriate and measured strategies to utilize pharmacological and lifestyle interventions aimed at alleviating CVD risk. This article is part of a Special Issue entitled "SI: CV Aging".
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Affiliation(s)
- Anthony J Donato
- University of Utah, Department of Internal Medicine, Division of Geriatrics, Salt Lake City, UT, USA; Veteran's Affairs Medical Center-Salt Lake City, Geriatrics Research Education and Clinical Center, Salt Lake City, UT, USA.
| | - R Garrett Morgan
- University of Washington, Department of Pathology, Seattle, WA, USA
| | - Ashley E Walker
- University of Utah, Department of Internal Medicine, Division of Geriatrics, Salt Lake City, UT, USA
| | - Lisa A Lesniewski
- University of Utah, Department of Internal Medicine, Division of Geriatrics, Salt Lake City, UT, USA; Veteran's Affairs Medical Center-Salt Lake City, Geriatrics Research Education and Clinical Center, Salt Lake City, UT, USA
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Vascular Ageing and Exercise: Focus on Cellular Reparative Processes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:3583956. [PMID: 26697131 PMCID: PMC4678076 DOI: 10.1155/2016/3583956] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/17/2015] [Accepted: 08/20/2015] [Indexed: 12/20/2022]
Abstract
Ageing is associated with an increased risk of developing noncommunicable diseases (NCDs), such as diabetes and cardiovascular disease (CVD). The increased risk can be attributable to increased prolonged exposure to oxidative stress. Often, CVD is preceded by endothelial dysfunction, which carries with it a proatherothrombotic phenotype. Endothelial senescence and reduced production and release of nitric oxide (NO) are associated with “vascular ageing” and are often accompanied by a reduced ability for the body to repair vascular damage, termed “reendothelialization.” Exercise has been repeatedly shown to confer protection against CVD and diabetes risk and incidence. Regular exercise promotes endothelial function and can prevent endothelial senescence, often through a reduction in oxidative stress. Recently, endothelial precursors, endothelial progenitor cells (EPC), have been shown to repair damaged endothelium, and reduced circulating number and/or function of these cells is associated with ageing. Exercise can modulate both number and function of these cells to promote endothelial homeostasis. In this review we look at the effects of advancing age on the endothelium and these endothelial precursors and how exercise appears to offset this “vascular ageing” process.
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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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Fujii N, Paull G, Meade RD, McGinn R, Stapleton JM, Akbari P, Kenny GP. Do nitric oxide synthase and cyclooxygenase contribute to the heat loss responses in older males exercising in the heat? J Physiol 2015; 593:3169-80. [PMID: 25820454 PMCID: PMC4532535 DOI: 10.1113/jp270330] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 03/18/2015] [Indexed: 01/30/2023] Open
Abstract
This study evaluated the separate and combined roles of nitric oxide synthase (NOS) and cyclooxygenase (COX) in forearm sweating and cutaneous vasodilatation in older adults during intermittent exercise in the heat. Twelve healthy older (62 ± 7 years) males performed two 30 min cycling bouts at a fixed rate of metabolic heat production (400 W) in the heat (35°C, 20% relative humidity). The exercise bouts were followed by 20 and 40 min of recovery, respectively. Forearm sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC, laser Doppler perfusion units/mean arterial pressure) were evaluated at four skin sites that were continuously perfused via intradermal microdialysis with: (1) lactated Ringer solution (Control), (2) 10 mm ketorolac (non-selective COX inhibitor), (3) 10 mm N(G) -nitro-l-arginine methyl ester (l-NAME; non-selective NOS inhibitor) or (4) a combination of 10 mm ketorolac + 10 mm l-NAME. Sweating was not different between the four sites during either exercise bout (main effect P = 0.92) (average of last 5 min of second exercise, Control, 0.80 ± 0.06; ketorolac, 0.77 ± 0.09; l-NAME, 0.74 ± 0.07; ketorolac + l-NAME, 0.77 ± 0.09 mg min(-1) cm(-2) ). During both exercise bouts, relative to CVC evaluated at the Control site (average of last 5 min of second exercise, 69 ± 6%max), CVC was similar at the ketorolac site (P = 0.62; 66 ± 4%max) whereas it was attenuated to a similar extent at both the l-NAME (49 ± 8%max) and ketorolac + l-NAME (54 ± 8%max) sites (both P < 0.05). Thus, we demonstrate that NOS and COX are not functionally involved in forearm sweating whereas only NOS contributes to forearm cutaneous vasodilatation in older adults during intermittent exercise in the heat.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of OttawaOttawa, ON, Canada
| | - Gabrielle Paull
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of OttawaOttawa, ON, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of OttawaOttawa, ON, Canada
| | - Ryan McGinn
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of OttawaOttawa, ON, Canada
| | - Jill M Stapleton
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of OttawaOttawa, ON, Canada
| | - Pegah Akbari
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of OttawaOttawa, ON, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of OttawaOttawa, ON, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research InstituteOttawa, ON, Canada
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Joyner MJ, Casey DP. Regulation of increased blood flow (hyperemia) to muscles during exercise: a hierarchy of competing physiological needs. Physiol Rev 2015; 95:549-601. [PMID: 25834232 DOI: 10.1152/physrev.00035.2013] [Citation(s) in RCA: 426] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans.
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Affiliation(s)
- Michael J Joyner
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Darren P Casey
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
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Dinenno FA. Skeletal muscle vasodilation during systemic hypoxia in humans. J Appl Physiol (1985) 2015; 120:216-25. [PMID: 26023228 DOI: 10.1152/japplphysiol.00256.2015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/21/2015] [Indexed: 11/22/2022] Open
Abstract
In humans, the net effect of acute systemic hypoxia in quiescent skeletal muscle is vasodilation despite significant reflex increases in muscle sympathetic vasoconstrictor nerve activity. This vasodilation increases tissue perfusion and oxygen delivery to maintain tissue oxygen consumption. Although several mechanisms may be involved, we recently tested the roles of two endothelial-derived substances during conditions of sympathoadrenal blockade to isolate local vascular control mechanisms: nitric oxide (NO) and prostaglandins (PGs). Our findings indicate that 1) NO normally plays a role in regulating vascular tone during hypoxia independent of the PG pathway; 2) PGs do not normally contribute to vascular tone during hypoxia, however, they do affect vascular tone when NO is inhibited; 3) NO and PGs are not independently obligatory to observe hypoxic vasodilation when assessed as a response from rest to steady-state hypoxia; and 4) combined NO and PG inhibition abolishes hypoxic vasodilation in human skeletal muscle. When the stimulus is exacerbated via combined submaximal rhythmic exercise and systemic hypoxia to cause further red blood cell (RBC) deoxygenation, skeletal muscle blood flow is augmented compared with normoxic exercise via local dilator mechanisms to maintain oxygen delivery to active tissue. Data obtained in a follow-up study indicate that combined NO and PG inhibition during hypoxic exercise blunts augmented vasodilation and hyperemia compared with control (normoxic) conditions by ∼50%; however, in contrast to hypoxia alone, the response is not abolished, suggesting that other local substances are involved. Factors associated with greater RBC deoxygenation such as ATP release, or nitrite reduction to NO, or both likely play a role in regulating this response.
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Affiliation(s)
- Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Center for Cardiovascular Research, Colorado State University, Fort Collins, Colorado
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Redundant vasodilator pathways underlying radial artery flow-mediated dilation are preserved in healthy aging. J Aging Res 2014; 2014:876125. [PMID: 24963406 PMCID: PMC4055391 DOI: 10.1155/2014/876125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/23/2014] [Accepted: 05/03/2014] [Indexed: 11/18/2022] Open
Abstract
Background. Blocking nitric oxide (NO) and vasodilator prostanoids (PN) does not consistently reduce flow-mediated dilation (FMD) in young adults. The impact of aging on the contribution of NO and PG to FMD is unknown. Methods. FMD was measured in older adults (n = 10, 65 ± 3 y) after arterial infusion of saline, N(G)-monomethyl-L-arginine (L-NMMA), and ketorolac + L-NMMA. Data were compared to published data in young adults. Results. L-NMMA reduced FMD in older adults (8.9 ± 3.6 to 5.9 ± 3.7%) although this was not statistically significant (P = 0.08) and did not differ (P = 0.74) from the reduction observed in young adults (10.0 ± 3.8 to 7.6 ± 4.7%; P = 0.03). Blocking PN did not affect FMD in young or older adults. In older adults, L-NMMA reduced (n = 6; range = 36-123% decrease), augmented (n = 3; 10-122% increase), or did not change FMD (n = 1; 0.4% increase). After PN blockade, FMD responses were reduced (n = 2), augmented (n = 6), or unaffected (n = 1). Conclusions. NO or PN blockade did not consistently reduce FMD in healthy older adults, suggesting the existence of redundant vasodilator phenotypes as observed previously in young adults.
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Taylor JL, Hines CN, Nicholson WT, Joyner MJ, Barnes JN. The effect of ageing and indomethacin on forearm reactive hyperaemia in healthy adults. Exp Physiol 2014; 99:859-67. [PMID: 24706194 DOI: 10.1113/expphysiol.2014.077941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have previously shown that non-selective cyclo-oxygenase inhibition, via indomethacin, unfavourably increased central blood pressure in older adults, with little effect in young adults. In addition, the vasoactive prostaglandins have been shown to contribute to both peripheral vasodilator responses and large artery function; however, there is little information available in older adults and conflicting reports in young adults on the extent to which resistance vessel function is influenced by indomethacin. Thus, we tested the hypothesis that cyclo-oxygenase inhibition using indomethacin would attenuate forearm vascular conductance during reactive hyperaemia in older adults compared with young adults. Forearm blood flow responses to 5 min of forearm ischaemia were measured in 26 healthy adults (13 young, 25 ± 5 years old; and 13 older, 65 ± 6 years old), using venous occlusion plethysmography before and after indomethacin. Baseline forearm blood flow and vascular conductance were not different between groups during either trial, and there were no age-related differences prior to cyclo-oxygenase inhibition. Peak forearm vascular conductance and blood flow were similar between groups before indomethacin, but lower in older adults after indomethacin compared with young adults (27 ± 4 versus 41 ± 4 ml (100 ml)(-1) min(-1) (100 mmHg)(-1), P = 0.02; and 23 ± 3 versus 33 ± 3 ml (100 ml)(-1) min(-1), P = 0.02, respectively). These results, in conjunction with our previous findings in large arteries, suggest that ageing alters the effect of cyclo-oxygenase inhibition on vascular responses, and specifically, the resistance vessel responses underlying reactive hyperaemia.
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Affiliation(s)
| | - Casey N Hines
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
| | | | | | - Jill N Barnes
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
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El Assar M, Angulo J, Rodríguez-Mañas L. Oxidative stress and vascular inflammation in aging. Free Radic Biol Med 2013; 65:380-401. [PMID: 23851032 DOI: 10.1016/j.freeradbiomed.2013.07.003] [Citation(s) in RCA: 412] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 12/13/2022]
Abstract
Vascular aging, a determinant factor for cardiovascular disease and health status in the elderly, is now viewed as a modifiable risk factor. Impaired endothelial vasodilation is a early hallmark of arterial aging that precedes the clinical manifestations of vascular dysfunction, the first step to cardiovascular disease and influencing vascular outcomes in the elderly. Accordingly, the preservation of endothelial function is thought to be an essential determinant of healthy aging. With special attention on the effects of aging on the endothelial function, this review is focused on the two main mechanisms of aging-related endothelial dysfunction: oxidative stress and inflammation. Aging vasculature generates an excess of the reactive oxygen species (ROS), superoxide and hydrogen peroxide, that compromise the vasodilatory activity of nitric oxide (NO) and facilitate the formation of the deleterious radical, peroxynitrite. Main sources of ROS are mitochondrial respiratory chain and NADPH oxidases, although NOS uncoupling could also account for ROS generation. In addition, reduced antioxidant response mediated by erythroid-2-related factor-2 (Nrf2) and downregulation of mitochondrial manganese superoxide dismutase (SOD2) contributes to the establishment of chronic oxidative stress in aged vessels. This is accompanied by a chronic low-grade inflammatory phenotype that participates in defective endothelial vasodilation. The redox-sensitive transcription factor, nuclear factor-κB (NF-κB), is upregulated in vascular cells from old subjects and drives a proinflammatory shift that feedbacks oxidative stress. This chronic NF-κB activation is contributed by increased angiotensin-II signaling and downregulated sirtuins and precludes adequate cellular response to acute ROS generation. Interventions targeted to recover endogenous antioxidant capacity and cellular stress response rather than exogenous antioxidants could reverse oxidative stress-inflammation vicious cycle in vascular aging. Lifestyle attitudes such as caloric restriction and exercise training appear as effective ways to overcome defective antioxidant response and inflammation, favoring successful vascular aging and decreasing the risk for cardiovascular disease.
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Affiliation(s)
- Mariam El Assar
- Fundación para la Investigación Biomédica, Hospital Universitario de Getafe, Getafe, Spain
| | - Javier Angulo
- Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Leocadio Rodríguez-Mañas
- Fundación para la Investigación Biomédica, Hospital Universitario de Getafe, Getafe, Spain; Servicio de Geriatría, Hospital Universitario de Getafe, Getafe, Spain.
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Limberg JK, Harrell JW, Johansson RE, Eldridge MW, Proctor LT, Sebranek JJ, Schrage WG. Microvascular function in younger adults with obesity and metabolic syndrome: role of oxidative stress. Am J Physiol Heart Circ Physiol 2013; 305:H1230-7. [PMID: 23934859 DOI: 10.1152/ajpheart.00291.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Older adults with cardiovascular disease exhibit microvascular dysfunction and increased levels of reactive oxygen species (ROS). We hypothesized that microvascular impairments begin early in the disease process and can be improved by scavenging ROS. Forearm blood flow (Doppler ultrasound) was measured in 45 young (32 ± 2 yr old) adults (n = 15/group) classified as lean, obese, and metabolic syndrome (MetSyn). Vasodilation in response to endothelial (ACh) and vascular smooth muscle [nitroprusside (NTP) and epoprostenol (Epo)] agonists was tested before and after intra-arterial infusion of ascorbic acid to scavenge ROS. Vasodilation was assessed as a rise in relative vascular conductance (ml·min(-1)·dl(-1)·100 mmHg(-1)). ACh and NTP responses were preserved (P = 0.825 and P = 0.924, respectively), whereas Epo responses were lower in obese and MetSyn adults (P < 0.05) than in lean controls. Scavenging of ROS via infusion of ascorbic acid resulted in an increase in ACh-mediated (P < 0.001) and NTP-mediated (P < 0.001) relative vascular conductance across all groups, suggesting that oxidative stress influences vascular responsiveness in adults with and without overt cardiovascular disease risk. Ascorbic acid had no effect on Epo-mediated vasodilation (P = 0.267). These results suggest that obese and MetSyn adults exhibit preserved endothelium-dependent vasodilation with reduced dependence on prostacyclin and are consistent with an upregulation of compensatory vascular control mechanisms.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Kinesiology, School of Education, University of Wisconsin, Madison, Wisconsin
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39
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Abstract
Blood flow increases to exercising skeletal muscle, and this increase is driven primarily by vasodilation in the contracting muscles. When oxygen delivery to the contracting muscles is altered by changes in arterial oxygen content, the magnitude of the vasodilator response to exercise changes. It is augmented during hypoxia and blunted during hyperoxia. Because the magnitude of the increased vasodilation during hypoxic exercise tends to keep oxygen delivery to the contracting muscles constant, we have termed this phenomenon "compensatory vasodilation." In a series of studies, we have explored metabolic, endothelial, and neural mechanisms that might contribute to compensatory vasodilation. These include the contribution of vasodilating substances like nitric oxide (NO) and adenosine, along with altered interactions between sympathetic vasoconstriction and metabolic vasodilation. We have also compared the compensatory vasodilator responses to hypoxic exercise with those seen when oxygen delivery to contracting muscles is altered by acute reductions in perfusion pressure. A synthesis of our findings indicate that NO contributes to the compensatory dilator responses during both hypoxia and hypoperfusion, while adenosine appears to contribute only during hypoperfusion. During hypoxia, the NO-mediated component is linked to a β-adrenergic receptor mechanism during lower intensity exercise, while another source of NO is engaged at higher exercise intensities. There are also subtle interactions between α-adrenergic vasoconstriction and metabolic vasodilation that influence the responses to hypoxia, hyperoxia, and hypoperfusion. Together our findings emphasize both the tight linkage of oxygen demand and supply during exercise and the redundant nature of the vasomotor responses to contraction.
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Nyberg M, Al-Khazraji BK, Mortensen SP, Jackson DN, Ellis CG, Hellsten Y. Effect of extraluminal ATP application on vascular tone and blood flow in skeletal muscle: implications for exercise hyperemia. Am J Physiol Regul Integr Comp Physiol 2013; 305:R281-90. [PMID: 23761642 DOI: 10.1152/ajpregu.00189.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
During skeletal muscle contractions, the concentration of ATP increases in muscle interstitial fluid as measured by microdialysis probes. This increase is associated with the magnitude of blood flow, suggesting that interstitial ATP may be important for contraction-induced vasodilation. However, interstitial ATP has solely been described to induce vasoconstriction in skeletal muscle. To examine whether interstitial ATP induces vasodilation in skeletal muscle and to what extent this vasoactive effect is mediated by formation of nitric oxide (NO) and prostanoids, three different experimental models were studied. The rat gluteus maximus skeletal muscle model was used to study changes in local skeletal muscle hemodynamics. Superfused ATP at concentrations found during muscle contractions (1-10 μM) increased blood flow by up to 400%. In this model, the underlying mechanism was also examined by inhibition of NO and prostanoid formation. Inhibition of these systems abolished the vasodilator effect of ATP. Cell-culture experiments verified ATP-induced formation of NO and prostacyclin in rat skeletal muscle microvascular endothelial cells, and ATP-induced formation of NO in rat skeletal muscle cells. To confirm these findings in humans, ATP was infused into skeletal muscle interstitium of healthy subjects via microdialysis probes and found to increase muscle interstitial concentrations of NO and prostacyclin by ~60% and ~40%, respectively. Collectively, these data suggest that a physiologically relevant elevation in interstitial ATP concentrations increases muscle blood flow, indicating that the contraction-induced increase in skeletal muscle interstitial [ATP] is important for exercise hyperemia. The vasodilator effect of ATP application is mediated by NO and prostanoid formation.
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Affiliation(s)
- Michael Nyberg
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.
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Ngo AT, Riemann M, Holstein-Rathlou NH, Torp-Pedersen C, Jensen LJ. Significance of K(ATP) channels, L-type Ca²⁺ channels and CYP450-4A enzymes in oxygen sensing in mouse cremaster muscle arterioles in vivo. BMC PHYSIOLOGY 2013; 13:8. [PMID: 23663730 PMCID: PMC3663688 DOI: 10.1186/1472-6793-13-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 05/08/2013] [Indexed: 12/20/2022]
Abstract
Background ATP-sensitive K+ channels (KATP channels), NO, prostaglandins, 20-HETE and L-type Ca2+ channels have all been suggested to be involved in oxygen sensing in skeletal muscle arterioles, but the role of the individual mechanisms remain controversial. We aimed to establish the importance of these mechanisms for oxygen sensing in arterioles in an in vivo model of metabolically active skeletal muscle. For this purpose we utilized the exteriorized cremaster muscle of anesthetized mice, in which the cremaster muscle was exposed to controlled perturbation of tissue PO2. Results Change from “high” oxygen tension (PO2 = 153.4 ± 3.4 mmHg) to “low” oxygen tension (PO2 = 13.8 ± 1.3 mmHg) dilated cremaster muscle arterioles from 11.0 ± 0.4 μm to 32.9 ± 0.9 μm (n = 28, P < 0.05). Glibenclamide (KATP channel blocker) caused maximal vasoconstriction, and abolished the dilation to low oxygen, whereas the KATP channel opener cromakalim caused maximal dilation and prevented the constriction to high oxygen. When adding cromakalim on top of glibenclamide or vice versa, the reactivity to oxygen was gradually restored. Inhibition of L-type Ca2+ channels using 3 μM nifedipine did not fully block basal tone in the arterioles, but rendered them unresponsive to changes in PO2. Inhibition of the CYP450-4A enzyme using DDMS blocked vasoconstriction to an increase in PO2, but had no effect on dilation to low PO2. Conclusions We conclude that: 1) L-type Ca2+ channels are central to oxygen sensing, 2) KATP channels are permissive for the arteriolar response to oxygen, but are not directly involved in the oxygen sensing mechanism and 3) CYP450-4A mediated 20-HETE production is involved in vasoconstriction to high PO2.
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Affiliation(s)
- Anh Thuc Ngo
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum institute, University of Copenhagen, Blegdamsvej 3, Copenhagen N, DK-2200, Denmark.
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Crecelius AR, Kirby BS, Luckasen GJ, Larson DG, Dinenno FA. Mechanisms of rapid vasodilation after a brief contraction in human skeletal muscle. Am J Physiol Heart Circ Physiol 2013; 305:H29-40. [PMID: 23645465 DOI: 10.1152/ajpheart.00298.2013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A monophasic increase in skeletal muscle blood flow is observed after a brief single forearm contraction in humans, yet the underlying vascular signaling pathways remain largely undetermined. Evidence from experimental animals indicates an obligatory role of vasodilation via K⁺-mediated smooth muscle hyperpolarization, and human data suggest little to no independent role for nitric oxide (NO) or vasodilating prostaglandins (PGs). We tested the hypothesis that K⁺-mediated vascular hyperpolarization underlies the rapid vasodilation in humans and that combined inhibition of NO and PGs would have a minimal effect on this response. We measured forearm blood flow (Doppler ultrasound) and calculated vascular conductance 10 s before and for 30 s after a single 1-s dynamic forearm contraction at 10%, 20%, and 40% maximum voluntary contraction in 16 young adults. To inhibit K⁺-mediated vasodilation, BaCl₂ and ouabain were infused intra-arterially to inhibit inwardly rectifying K⁺ channels and Na⁺-K⁺-ATPase, respectively. Combined enzymatic inhibition of NO and PG synthesis occurred via NG-monomethyl-L-arginine (L-NMMA; NO synthase) and ketorolac (cyclooxygenase), respectively. In protocol 1 (n = 8), BaCl₂ + ouabain reduced peak vasodilation (range: 30-45%, P < 0.05) and total postcontraction vasodilation (area under the curve, ~55-75% from control) at all intensities. Contrary to our hypothesis, L-NMMA + ketorolac had a further impact (peak: ~60% and area under the curve: ~80% from control). In protocol 2 (n = 8), the order of inhibitors was reversed, and the findings were remarkably similar. We conclude that K⁺-mediated hyperpolarization and NO and PGs, in combination, significantly contribute to contraction-induced rapid vasodilation and that inhibition of these signaling pathways nearly abolishes this phenomenon in humans.
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Affiliation(s)
- Anne R Crecelius
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA
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Chang L, Villacorta L, Li R, Hamblin M, Xu W, Dou C, Zhang J, Wu J, Zeng R, Chen YE. Loss of perivascular adipose tissue on peroxisome proliferator-activated receptor-γ deletion in smooth muscle cells impairs intravascular thermoregulation and enhances atherosclerosis. Circulation 2012; 126:1067-78. [PMID: 22855570 DOI: 10.1161/circulationaha.112.104489] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Perivascular adipose tissue (PVAT) surrounds most vessels and shares common features with brown adipose tissue (BAT). Although adaptive thermogenesis in BAT increases energy expenditure and is beneficial for metabolic diseases, little is known about the role of PVAT in vascular diseases such as atherosclerosis. We hypothesize that the thermogenic function of PVAT regulates intravascular temperature and reduces atherosclerosis. METHODS AND RESULTS PVAT shares similar structural and proteomics with BAT. We demonstrated that PVAT has thermogenic properties similar to BAT in response to cold stimuli in vivo. Proteomics analysis of the PVAT from mice housed in a cold environment identified differential expression in proteins highly related to cellular metabolic processes. In a mouse model deficient in peroxisome proliferator-activated receptor-γ in smooth muscle cells (SMPG KO mice), we uncovered a complete absence of PVAT surrounding the vasculature, likely caused by peroxisome proliferator-activated receptor-γ deletion in the perivascular adipocyte precursor cells as well. Lack of PVAT, which results in loss of its thermogenic activity, impaired vascular homeostasis, which caused temperature loss and endothelial dysfunction. We further showed that cold exposure inhibits atherosclerosis and improves endothelial function in mice with intact PVAT but not in SMPG KO mice as a result of impaired lipid clearance. Proinflammatory cytokine expression in PVAT is not altered on exposure to cold. Finally, prostacyclin released from PVAT contributes to the vascular protection against endothelial dysfunction. CONCLUSIONS PVAT is a vasoactive organ with functional characteristics similar to BAT and is essential for intravascular thermoregulation of cold acclimation. This thermogenic capacity of PVAT plays an important protective role in the pathogenesis of atherosclerosis.
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MESH Headings
- Adaptation, Physiological/physiology
- Adipocytes/metabolism
- Adipose Tissue/pathology
- Adipose Tissue/physiopathology
- Adipose Tissue, Brown/metabolism
- Animals
- Aorta
- Apolipoproteins E/deficiency
- Apolipoproteins E/genetics
- Atherosclerosis/etiology
- Atherosclerosis/prevention & control
- Body Temperature Regulation/physiology
- Carotid Arteries
- Cold Temperature
- Cytokines/metabolism
- Diet, Atherogenic
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Gene Expression Regulation/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- PPAR gamma/deficiency
- PPAR gamma/genetics
- Prostaglandins I/physiology
- Proteomics
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Affiliation(s)
- Lin Chang
- Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
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44
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Chang L, Villacorta L, Li R, Hamblin M, Xu W, Dou C, Zhang J, Wu J, Zeng R, Chen YE. Loss of perivascular adipose tissue on peroxisome proliferator-activated receptor-γ deletion in smooth muscle cells impairs intravascular thermoregulation and enhances atherosclerosis. Circulation 2012. [PMID: 22855570 DOI: 10.1016/circulationaha.112.104489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Perivascular adipose tissue (PVAT) surrounds most vessels and shares common features with brown adipose tissue (BAT). Although adaptive thermogenesis in BAT increases energy expenditure and is beneficial for metabolic diseases, little is known about the role of PVAT in vascular diseases such as atherosclerosis. We hypothesize that the thermogenic function of PVAT regulates intravascular temperature and reduces atherosclerosis. METHODS AND RESULTS PVAT shares similar structural and proteomics with BAT. We demonstrated that PVAT has thermogenic properties similar to BAT in response to cold stimuli in vivo. Proteomics analysis of the PVAT from mice housed in a cold environment identified differential expression in proteins highly related to cellular metabolic processes. In a mouse model deficient in peroxisome proliferator-activated receptor-γ in smooth muscle cells (SMPG KO mice), we uncovered a complete absence of PVAT surrounding the vasculature, likely caused by peroxisome proliferator-activated receptor-γ deletion in the perivascular adipocyte precursor cells as well. Lack of PVAT, which results in loss of its thermogenic activity, impaired vascular homeostasis, which caused temperature loss and endothelial dysfunction. We further showed that cold exposure inhibits atherosclerosis and improves endothelial function in mice with intact PVAT but not in SMPG KO mice as a result of impaired lipid clearance. Proinflammatory cytokine expression in PVAT is not altered on exposure to cold. Finally, prostacyclin released from PVAT contributes to the vascular protection against endothelial dysfunction. CONCLUSIONS PVAT is a vasoactive organ with functional characteristics similar to BAT and is essential for intravascular thermoregulation of cold acclimation. This thermogenic capacity of PVAT plays an important protective role in the pathogenesis of atherosclerosis.
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MESH Headings
- Adaptation, Physiological/physiology
- Adipocytes/metabolism
- Adipose Tissue/pathology
- Adipose Tissue/physiopathology
- Adipose Tissue, Brown/metabolism
- Animals
- Aorta
- Apolipoproteins E/deficiency
- Apolipoproteins E/genetics
- Atherosclerosis/etiology
- Atherosclerosis/prevention & control
- Body Temperature Regulation/physiology
- Carotid Arteries
- Cold Temperature
- Cytokines/metabolism
- Diet, Atherogenic
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Gene Expression Regulation/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- PPAR gamma/deficiency
- PPAR gamma/genetics
- Prostaglandins I/physiology
- Proteomics
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Affiliation(s)
- Lin Chang
- Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
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Barnes JN, Casey DP, Hines CN, Nicholson WT, Joyner MJ. Cyclooxygenase inhibition augments central blood pressure and aortic wave reflection in aging humans. Am J Physiol Heart Circ Physiol 2012; 302:H2629-34. [PMID: 22505642 DOI: 10.1152/ajpheart.00032.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The augmentation index and central blood pressure increase with normal aging. Recently, cyclooxygenase (COX) inhibitors, commonly used for the treatment of pain, have been associated with transient increases in the risk of cardiovascular events. We examined the effects of the COX inhibitor indomethacin (Indo) on central arterial hemodynamics and wave reflection characteristics in young and old healthy adults. High-fidelity radial arterial pressure waveforms were measured noninvasively by applanation tonometry before (control) and after Indo treatment in young (25 ± 5 yr, 7 men and 6 women) and old (64 ± 6 yr, 5 men and 6 women) subjects. Aortic systolic (control: 115 ± 3 mmHg vs. Indo: 125 ± 5 mmHg, P < 0.05) and diastolic (control: 74 ± 2 mmHg vs. Indo: 79 ± 3 mmHg, P < 0.05) pressures were elevated after Indo treatment in older subjects, whereas only diastolic pressure was elevated in young subjects (control: 71 ± 2 mmHg vs. Indo: 76 ± 1 mmHg, P < 0.05). Mean arterial pressure increased in both young and old adults after Indo treatment (P < 0.05). The aortic augmentation index and augmented pressure were elevated after Indo treatment in older subjects (control: 30 ± 5% vs. Indo 36 ± 6% and control 12 ± 1 mmHg vs. Indo: 18 ± 2 mmHg, respectively, P < 0.05), whereas pulse pressure amplification decreased (change: 8 ± 3%, P < 0.05). In addition, older subjects had a 61 ± 11% increase in wasted left ventricular energy after Indo treatment (P < 0.05). In contrast, young subjects showed no significant changes in any of the variables of interest. Taken together, these results demonstrate that COX inhibition with Indo unfavorably increases central wave reflection and augments aortic pressure in old but not young subjects. Our results suggest that aging individuals have a limited ability to compensate for the acute hemodynamic changes caused by systemic COX inhibition.
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Affiliation(s)
- Jill N Barnes
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Barnes JN, Schmidt JE, Nicholson WT, Joyner MJ. Cyclooxygenase inhibition abolishes age-related differences in cerebral vasodilator responses to hypercapnia. J Appl Physiol (1985) 2012; 112:1884-90. [PMID: 22442028 DOI: 10.1152/japplphysiol.01270.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Blood flow and vasodilatory responses are altered by age in a number of vascular beds, including the cerebral circulation. To test the role of prostaglandins as regulators of cerebral vascular function, we examined cerebral vasodilator responses to CO(2) (cerebrovascular reactivity) in young (26 ± 5 yr; 6 males/6 females) and older (65 ± 6 yr, 5 males/5 females) healthy humans before and after cyclooxygenase inhibition (using indomethacin). Middle cerebral artery velocity (MCAv) responses to stepped hypercapnia were measured before and 90 min after indomethacin. Changes in MCAv during the recovery from hypercapnia (vasoconstrictor responses) were also evaluated before and after indomethacin. Cerebrovascular reactivity was calculated using linear regression between MCAv and end-tidal CO(2). Young adults demonstrated greater MCAv (55 ± 6 vs. 39 ± 5 cm/s: P < 0.05) and MCAv reactivity (1.67 ± 0.20 vs. 1.09 ± 0.19 cm·s(-1)·mmHg(-1); P < 0.05) to hypercapnia compared with older adults (P < 0.05). In both groups MCAv and MCAv reactivity decreased between control and indomethacin. Furthermore, the age-related differences in these cerebrovascular variables were abolished by indomethacin. During the recovery from hypercapnia, there were no age-related differences in MCAv reactivity; however, indomethacin significantly reduced the MCAv reactivity in both groups. Taken together, these results suggest that cerebral blood flow velocity and cerebrovascular reactivity are attenuated in aging humans, and may be due to a loss of prostaglandin-mediated vasodilation.
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Affiliation(s)
- Jill N Barnes
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA.
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47
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Aging-shifted prostaglandin profile in endothelium as a factor in cardiovascular disorders. J Aging Res 2012; 2012:121390. [PMID: 22500225 PMCID: PMC3303603 DOI: 10.1155/2012/121390] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 10/10/2011] [Accepted: 10/28/2011] [Indexed: 12/31/2022] Open
Abstract
Age-associated endothelium dysfunction is a major risk factor for the development of cardiovascular diseases. Endothelium-synthesized prostaglandins and thromboxane are local hormones, which mediate vasodilation and vasoconstriction and critically maintain vascular homeostasis. Accumulating evidence indicates that the age-related changes in endothelial eicosanoids contribute to decline in endothelium function and are associated with pathological dysfunction. In this review we summarize currently available information on aging-shifted prostaglandin profiles in endothelium and how these shifts are associated with cardiovascular disorders, providing one molecular mechanism of age-associated endothelium dysfunction and cardiovascular diseases.
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Heterogeneous vascular responses to hypoxic forearm exercise in young and older adults. Eur J Appl Physiol 2011; 112:3087-95. [PMID: 22198326 DOI: 10.1007/s00421-011-2280-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 12/05/2011] [Indexed: 10/14/2022]
Abstract
We aimed to assess age-related differences in compensatory hypoxic vasodilation during moderate-to-high dynamic exercise at absolute workloads. We hypothesized healthy older adults (n = 12, 61 ± 1 years) would exhibit impaired hypoxic vasodilation at a moderate absolute workload, and this effect would be exaggerated at a higher workload when compared to young adults (n = 17, 27 ± 2 years). Forearm blood flow (FBF) was measured with Doppler ultrasound. Dynamic forearm exercise (20 contractions/min) was completed at two absolute workloads (8 and 12 kg) under normoxic (0.21 FiO2, ~98% SpO2) and isocapnic hypoxic (~0.10 FiO2, 80% SpO2) conditions performed in random order. FBF was normalized as forearm vascular conductance (FBF / mean arterial blood pressure = FVC) to control for differences in blood pressure and to assess vasodilation. FVC increased with exercise and hypoxia (main effects, p < 0.05); vascular responses were not different between young and older adults (interaction effect exercise × group p = 0.37 and hypoxia × group p = 0.96). Results were confirmed when analyzed as either an absolute or relative change in FVC (ΔFVC and %ΔFVC, respectively). Although group responses to hypoxia were not different, individual results were highly variable (i.e., some adults constricted and others dilated to hypoxia). These data suggest (1) compensatory hypoxic vasodilation in older adults is not impaired during forearm exercise at both moderate and higher absolute exercise intensities, and (2) vascular responses to hypoxia are heterogeneous in both young and older adults. Results suggest unique individual differences exist in factors regulating vascular responses to hypoxia.
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49
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Hansen AH, Nyberg M, Bangsbo J, Saltin B, Hellsten Y. Exercise training alters the balance between vasoactive compounds in skeletal muscle of individuals with essential hypertension. Hypertension 2011; 58:943-9. [PMID: 21896936 DOI: 10.1161/hypertensionaha.111.176529] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of physical training on the formation of vasodilating and vasoconstricting compounds, as well as on related proteins important for vascular function, were examined in skeletal muscle of individuals with essential hypertension (n=10). Muscle microdialysis samples were obtained from subjects with hypertension before and after 16 weeks of physical training. Muscle dialysates were analyzed for thromboxane A(2), prostacyclin, nucleotides, and nitrite/nitrate. Protein levels of thromboxane synthase, prostacyclin synthase, cyclooxygenase 1 and 2, endothelial nitric oxide synthase (eNOS), cystathionine-γ-lyase, cytochrome P450 4A and 2C9, and the purinergic receptors P2X1 and P2Y2 were determined in skeletal muscle. The protein levels were compared with those of normotensive control subjects (n=12). Resting muscle dialysate thromboxane A(2) and prostacyclin concentrations were lower (P<0.05) after training compared with before training. Before training, dialysate thromboxane A(2) decreased with acute exercise, whereas after training, no changes were found. Before training, dialysate prostacyclin levels did not increase with acute exercise, whereas after training there was an 82% (P<0.05) increase from rest to exercise. The exercise-induced increase in ATP and ADP was markedly reduced after training (P<0.05). The amount of eNOS protein in the hypertensive subjects was 40% lower (P<0.05) than in the normotensive control subjects, whereas cystathionine-γ-lyase levels were 25% higher (P<0.05), potentially compensating for the lower eNOS level. We conclude that exercise training alters the balance between vasodilating and vasoconstricting compounds as evidenced by a decrease in the level of thromboxane, reduction in the exercise-induced increase in ATP and a greater exercise-induced increase in prostacyclin.
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Affiliation(s)
- Ane H Hansen
- Copenhagen Muscle Research Centre, University of Copenhagen, Department of Exercise and Sports Sciences, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
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Casey DP, Joyner MJ. Local control of skeletal muscle blood flow during exercise: influence of available oxygen. J Appl Physiol (1985) 2011; 111:1527-38. [PMID: 21885800 DOI: 10.1152/japplphysiol.00895.2011] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Reductions in oxygen availability (O(2)) by either reduced arterial O(2) content or reduced perfusion pressure can have profound influences on the circulation, including vasodilation in skeletal muscle vascular beds. The purpose of this review is to put into context the present evidence regarding mechanisms responsible for the local control of blood flow during acute systemic hypoxia and/or local hypoperfusion in contracting muscle. The combination of submaximal exercise and hypoxia produces a "compensatory" vasodilation and augmented blood flow in contracting muscles relative to the same level of exercise under normoxic conditions. A similar compensatory vasodilation is observed in response to local reductions in oxygen availability (i.e., hypoperfusion) during normoxic exercise. Available evidence suggests that nitric oxide (NO) contributes to the compensatory dilator response under each of these conditions, whereas adenosine appears to only play a role during hypoperfusion. During systemic hypoxia the NO-mediated component of the compensatory vasodilation is regulated through a β-adrenergic receptor mechanism at low-intensity exercise, while an additional (not yet identified) source of NO is likely to be engaged as exercise intensity increases during hypoxia. Potential candidates for stimulating and/or interacting with NO at higher exercise intensities include prostaglandins and/or ATP. Conversely, prostaglandins do not appear to play a role in the compensatory vasodilation during exercise with hypoperfusion. Taken together, the data for both hypoxia and hypoperfusion suggest NO is important in the compensatory vasodilation seen when oxygen availability is limited. This is important from a basic biological perspective and also has pathophysiological implications for diseases associated with either hypoxia or hypoperfusion.
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Affiliation(s)
- Darren P Casey
- Dept. of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA.
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