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Ahmad T, Muhammad S, Umar M, Azhar MU, Ahmed A, Ahmad A, Ullah R. Spatial distribution of physicochemical parameters and drinking and irrigation water quality indices in the Jhelum River, Pakistan. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2024; 46:263. [PMID: 38954066 DOI: 10.1007/s10653-024-02026-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 05/05/2024] [Indexed: 07/04/2024]
Abstract
Sustainable management of river systems is a serious concern, requiring vigilant monitoring of water contamination levels that could potentially threaten the ecological community. This study focused on the evaluation of water quality in the Jhelum River (JR), Azad Jammu and Kashmir, and northern Punjab, Pakistan. To achieve this, 60 water samples were collected from various points within the JR Basin (JRB) and subjected to a comprehensive analysis of their physicochemical parameters. The study findings indicated that the concentrations of physicochemical parameters in the JRB water remained within safety thresholds for both drinking and irrigation water, as established by the World Health Organization and Pakistan Environmental Protection Agency. These physicochemical parameters refer to various chemical and physical characteristics of the water that can have implications for both human health (drinking water) and agricultural practices (irrigation water). The spatial variations throughout the river course distinguished between the upstream, midstream, and downstream sections. Specifically, the downstream section exhibited significantly higher values for physicochemical parameters and a broader range, highlighting a substantial decline in its quality. Significant disparities in mean values and ranges were evident, particularly in the case of nitrates and total dissolved solids, when the downstream section was compared with its upstream and midstream counterparts. These variations indicated a deteriorating downstream water quality profile, which is likely attributable to a combination of geological and anthropogenic influences. Despite the observed deterioration in the downstream water quality, this study underscores that the JRB within the upper Indus Basin remains safe and suitable for domestic and agricultural purposes. The JRB was evaluated for various irrigation water quality indices. The principal component analysis conducted in this study revealed distinct covariance patterns among water quality variables, with the first five components explaining approximately 79% of the total variance. Recommending the continued utilization of the JRB for irrigation, we advocate for the preservation and enhancement of water quality in the downstream regions.
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Affiliation(s)
- Tofeeq Ahmad
- Department of Geosciences, College of Science, United Arab Emirates University, P.O. Box 15551, Al Ain, United Arab Emirates
- National Water and Energy Center, United Arab Emirates University, P.O. Box 15551, Al Ain, United Arab Emirates
- Department of Earth Sciences, The University of Haripur, Haripur, 22620, Pakistan
| | - Said Muhammad
- National Centre of Excellence in Geology, University of Peshawar, Peshawar, 25130, Pakistan
| | - Muhammad Umar
- Department of Earth Sciences, The University of Haripur, Haripur, 22620, Pakistan
| | - Muhammad Usman Azhar
- Department of Earth Sciences, The University of Haripur, Haripur, 22620, Pakistan
| | - Alaa Ahmed
- Department of Geosciences, College of Science, United Arab Emirates University, P.O. Box 15551, Al Ain, United Arab Emirates.
- National Water and Energy Center, United Arab Emirates University, P.O. Box 15551, Al Ain, United Arab Emirates.
| | - Ashfaq Ahmad
- Department of Chemistry, College of Science, King Saud University, 11451, Riyadh, Saudi Arabia
| | - Rizwan Ullah
- Department of River Ecology, Helmholtz Centre for Environmental Research-UFZ, Brückstra.3a, 39114, Magdeburg, Germany
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Pio-Lopez L, Levin M. Aging as a loss of morphostatic information: A developmental bioelectricity perspective. Ageing Res Rev 2024; 97:102310. [PMID: 38636560 DOI: 10.1016/j.arr.2024.102310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 02/21/2024] [Accepted: 04/12/2024] [Indexed: 04/20/2024]
Abstract
Maintaining order at the tissue level is crucial throughout the lifespan, as failure can lead to cancer and an accumulation of molecular and cellular disorders. Perhaps, the most consistent and pervasive result of these failures is aging, which is characterized by the progressive loss of function and decline in the ability to maintain anatomical homeostasis and reproduce. This leads to organ malfunction, diseases, and ultimately death. The traditional understanding of aging is that it is caused by the accumulation of molecular and cellular damage. In this article, we propose a complementary view of aging from the perspective of endogenous bioelectricity which has not yet been integrated into aging research. We propose a view of aging as a morphostasis defect, a loss of biophysical prepattern information, encoding anatomical setpoints used for dynamic tissue and organ homeostasis. We hypothesize that this is specifically driven by abrogation of the endogenous bioelectric signaling that normally harnesses individual cell behaviors toward the creation and upkeep of complex multicellular structures in vivo. Herein, we first describe bioelectricity as the physiological software of life, and then identify and discuss the links between bioelectricity and life extension strategies and age-related diseases. We develop a bridge between aging and regeneration via bioelectric signaling that suggests a research program for healthful longevity via morphoceuticals. Finally, we discuss the broader implications of the homologies between development, aging, cancer and regeneration and how morphoceuticals can be developed for aging.
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Affiliation(s)
- Léo Pio-Lopez
- Allen Discovery Center, Tufts University, Medford, MA 02155, USA
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, MA 02155, USA; Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA.
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3
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Flori L, Spezzini J, Calderone V, Testai L. Role of mitochondrial potassium channels in ageing. Mitochondrion 2024; 76:101857. [PMID: 38403095 DOI: 10.1016/j.mito.2024.101857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Ageing is described as an inevitable decline in body functions over time and an increase in susceptibility to age-related diseases. Therefore, the increase of life expectancy is also viewed as a condition in which many elderly will develop age-related diseases and disabilities, such as cardiovascular, metabolic, neurological and oncological ones. Currently, several recognized cellular hallmarks of senescence are taken in consideration to evaluate the level of biological ageing and are the topic to plan preventive/curative anti-ageing interventions, including genomic instability, epigenetic alterations, and mitochondrial dysfunction. In this scenario, alterations in the function/expression of mitochondrial ion channels have been found in ageing and associated to an impairment of calcium cycling and a reduced mitochondrial membrane potential. Although several ion channels have been described at mitochondrial level, undoubtedly the mitochondrial potassium (mitoK) channels are the most investigated. Therefore, this review summarized the evidence that sheds to light a correlation between age-related diseases and alteration of mitoK channels, focusing the attention of the main age-related diseases, i.e. cardiovascular, neurological and oncological ones.
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Affiliation(s)
- Lorenzo Flori
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Vincenzo Calderone
- Department of Pharmacy, University of Pisa, Pisa, Italy; Interdepartmental Research Centre of Ageing Biology and Pathology, University of Pisa, Pisa, Italy
| | - Lara Testai
- Department of Pharmacy, University of Pisa, Pisa, Italy; Interdepartmental Research Centre of Ageing Biology and Pathology, University of Pisa, Pisa, Italy.
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4
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Jensen LJ. Functional, Structural and Proteomic Effects of Ageing in Resistance Arteries. Int J Mol Sci 2024; 25:2601. [PMID: 38473847 DOI: 10.3390/ijms25052601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
The normal ageing process affects resistance arteries, leading to various functional and structural changes. Systolic hypertension is a common occurrence in human ageing, and it is associated with large artery stiffening, heightened pulsatility, small artery remodeling, and damage to critical microvascular structures. Starting from young adulthood, a progressive elevation in the mean arterial pressure is evidenced by clinical and epidemiological data as well as findings from animal models. The myogenic response, a protective mechanism for the microcirculation, may face disruptions during ageing. The dysregulation of calcium entry channels (L-type, T-type, and TRP channels), dysfunction in intracellular calcium storage and extrusion mechanisms, altered expression of potassium channels, and a change in smooth muscle calcium sensitization may contribute to the age-related dysregulation of myogenic tone. Flow-mediated vasodilation, a hallmark of endothelial function, is compromised in ageing. This endothelial dysfunction is related to increased oxidative stress, lower nitric oxide bioavailability, and a low-grade inflammatory response, further exacerbating vascular dysfunction. Resistance artery remodeling in ageing emerges as a hypertrophic response of the vessel wall that is typically observed in conjunction with outward remodeling (in normotension), or as inward hypertrophic remodeling (in hypertension). The remodeling process involves oxidative stress, inflammation, reorganization of actin cytoskeletal components, and extracellular matrix fiber proteins. Reactive oxygen species (ROS) signaling and chronic low-grade inflammation play substantial roles in age-related vascular dysfunction. Due to its role in the regulation of vascular tone and structural proteins, the RhoA/Rho-kinase pathway is an important target in age-related vascular dysfunction and diseases. Understanding the intricate interplay of these factors is crucial for developing targeted interventions to mitigate the consequences of ageing on resistance arteries and enhance the overall vascular health.
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Affiliation(s)
- Lars Jørn Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg C, Denmark
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Vichare R, Saleem F, Mansour H, Bojkovic K, Cheng F, Biswal M, Panguluri SK. Impact of age and sex on hyperoxia-induced cardiovascular pathophysiology. Mech Ageing Dev 2022; 208:111727. [PMID: 36075315 DOI: 10.1016/j.mad.2022.111727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/17/2022] [Accepted: 08/23/2022] [Indexed: 12/30/2022]
Abstract
Hyperoxia is characterized by pronounced inflammatory responses, pulmonary cell apoptosis, and adverse cardiac remodeling due to an excess supply of oxygen. Hyperoxic episodes are frequent in mechanically ventilated patients and are associated with in-hospital mortality. This study extends the analysis of prior published research by our group as it investigates the influence of age in male and female rodents exposed to hyperoxic conditions. Age is an independent cardiovascular risk factor, often compounded by variables like obesity, diabetes, and a decline in sex hormones and their receptors. This study simulates clinical hyperoxia by subjecting rodents to > 90 % of oxygen for 72 h and compares the changes in cardiac structural and functional parameters with those exposed to normal air. While in both sexes conduction abnormalities with ageing were discernible, aged females owing to their inherent higher baseline QTc, were at a higher risk of developing arrhythmias as compared to age-matched males. Quantitative real-time RT-PCR and western blot analysis reflected altered expression of cardiac potassium channels, resulting in conduction abnormalities in aged female rodents. Unaffected by age and sex, hyperoxia-treated mice had altered body composition, as evidenced by a considerable reduction in body weight. Interestingly, compensatory hypertrophy observed as a protective mechanism in young males was absent in aged males, whereas protection of hearts from hyperoxia-induced cardiac hypertrophy was absent in aged female mice, both of which may be at least in part due to a reduction in sex steroid receptors and the systemic steroid levels. Finally, statistical analysis revealed that hyperoxia had the greatest impact on most of the cardiac parameters, followed by age and then sex. This data established an imperative finding that can change the provision of care for aged individuals admitted to ICU by elucidating the impact of intrinsic aging on hyperoxia-induced cardiac remodeling.
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Affiliation(s)
- Riddhi Vichare
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Faizan Saleem
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Hussein Mansour
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Katarina Bojkovic
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Feng Cheng
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Manas Biswal
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA; College of Medicine Internal Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Siva Kumar Panguluri
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA; Cell Biology, Microbiology and Molecular Biology, College of Arts and Sciences, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA.
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6
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Harraz OF, Jensen LJ. Vascular calcium signalling and ageing. J Physiol 2021; 599:5361-5377. [PMID: 34705288 PMCID: PMC9002240 DOI: 10.1113/jp280950] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/12/2021] [Indexed: 02/05/2023] Open
Abstract
Changes in cellular Ca2+ levels have major influences on vascular function and blood pressure regulation. Vascular smooth muscle cells (SMCs) and endothelial cells (ECs) orchestrate vascular activity in distinct ways, often involving highly specific fluctuations in Ca2+ signalling. Ageing is a major risk factor for cardiovascular diseases, but the impact of ageing per se on vascular Ca2+ signalling has received insufficient attention. We reviewed the literature for age-related changes in Ca2+ signalling in relation to vascular structure and function. Vascular tone dysregulation in several vascular beds has been linked to abnormal expression or activity of SMC voltage-gated Ca2+ channels, Ca2+ -activated K+ channels or TRPC6 channels. Some of these effects were linked to altered caveolae density, microRNA expression or 20-HETE abundance. Intracellular store Ca2+ handling was suppressed in ageing mainly via reduced expression of intracellular Ca2+ release channels, and Ca2+ reuptake or efflux pumps. An increase in mitochondrial Ca2+ uptake, leading to oxidative stress, could also play a role in SMC hypercontractility and structural remodelling in ageing. In ECs, ageing entailed diverse effects on spontaneous and evoked Ca2+ transients, as well as structural changes at the EC-SMC interface. The concerted effects of altered Ca2+ signalling on myogenic tone, endothelium-dependent vasodilatation, and vascular structure are likely to contribute to blood pressure dysregulation and blood flow distribution deficits in critical organs. With the increase in the world's ageing population, future studies should be directed at solving specific ageing-induced Ca2+ signalling deficits to combat the imminent accelerated vascular ageing and increased risk of cardiovascular diseases.
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Affiliation(s)
- Osama F. Harraz
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA,Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, Vermont, USA
| | - Lars Jørn Jensen
- Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
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Abstract
Mitochondria have been recognized as key organelles in cardiac physiology and are potential targets for clinical interventions to improve cardiac function. Mitochondrial dysfunction has been accepted as a major contributor to the development of heart failure. The main function of mitochondria is to meet the high energy demands of the heart by oxidative metabolism. Ionic homeostasis in mitochondria directly regulates oxidative metabolism, and any disruption in ionic homeostasis causes mitochondrial dysfunction and eventually contractile failure. The mitochondrial ionic homeostasis is closely coupled with inner mitochondrial membrane potential. To regulate and maintain ionic homeostasis, mitochondrial membranes are equipped with ion transporting proteins. Ion transport mechanisms involving several different ion channels and transporters are highly efficient and dynamic, thus helping to maintain the ionic homeostasis of ions as well as their salts present in the mitochondrial matrix. In recent years, several novel proteins have been identified on the mitochondrial membranes and these proteins are actively being pursued in research for roles in the organ as well as organelle physiology. In this article, the role of mitochondrial ion channels in cardiac function is reviewed. In recent times, the major focus of the mitochondrial ion channel field is to establish molecular identities as well as assigning specific functions to them. Given the diversity of mitochondrial ion channels and their unique roles in cardiac function, they present novel and viable therapeutic targets for cardiac diseases.
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Affiliation(s)
- Harpreet Singh
- Department of Physiology and Cell Biology, The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, Ohio
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8
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Tracy EP, Hughes W, Beare JE, Rowe G, Beyer A, LeBlanc AJ. Aging-Induced Impairment of Vascular Function: Mitochondrial Redox Contributions and Physiological/Clinical Implications. Antioxid Redox Signal 2021; 35:974-1015. [PMID: 34314229 PMCID: PMC8905248 DOI: 10.1089/ars.2021.0031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Significance: The vasculature responds to the respiratory needs of tissue by modulating luminal diameter through smooth muscle constriction or relaxation. Coronary perfusion, diastolic function, and coronary flow reserve are drastically reduced with aging. This loss of blood flow contributes to and exacerbates pathological processes such as angina pectoris, atherosclerosis, and coronary artery and microvascular disease. Recent Advances: Increased attention has recently been given to defining mechanisms behind aging-mediated loss of vascular function and development of therapeutic strategies to restore youthful vascular responsiveness. The ultimate goal aims at providing new avenues for symptom management, reversal of tissue damage, and preventing or delaying of aging-induced vascular damage and dysfunction in the first place. Critical Issues: Our major objective is to describe how aging-associated mitochondrial dysfunction contributes to endothelial and smooth muscle dysfunction via dysregulated reactive oxygen species production, the clinical impact of this phenomenon, and to discuss emerging therapeutic strategies. Pathological changes in regulation of mitochondrial oxidative and nitrosative balance (Section 1) and mitochondrial dynamics of fission/fusion (Section 2) have widespread effects on the mechanisms underlying the ability of the vasculature to relax, leading to hyperconstriction with aging. We will focus on flow-mediated dilation, endothelial hyperpolarizing factors (Sections 3 and 4), and adrenergic receptors (Section 5), as outlined in Figure 1. The clinical implications of these changes on major adverse cardiac events and mortality are described (Section 6). Future Directions: We discuss antioxidative therapeutic strategies currently in development to restore mitochondrial redox homeostasis and subsequently vascular function and evaluate their potential clinical impact (Section 7). Antioxid. Redox Signal. 35, 974-1015.
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Affiliation(s)
- Evan Paul Tracy
- Department of Physiology, University of Louisville, Louisville, Kentucky, USA
| | - William Hughes
- Department of Medicine and Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Jason E Beare
- Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky, USA.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
| | - Gabrielle Rowe
- Department of Physiology, University of Louisville, Louisville, Kentucky, USA
| | - Andreas Beyer
- Department of Medicine and Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Amanda Jo LeBlanc
- Department of Physiology, University of Louisville, Louisville, Kentucky, USA.,Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky, USA
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Harraz OF, Jensen LJ. Aging, calcium channel signaling and vascular tone. Mech Ageing Dev 2020; 191:111336. [PMID: 32918949 PMCID: PMC8511598 DOI: 10.1016/j.mad.2020.111336] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/13/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
Calcium signaling in vascular smooth muscle is crucial for arterial tone regulation and vascular function. Several proteins, including Ca2+ channels, function in an orchestrated fashion so that blood vessels can sense and respond to physiological stimuli such as changes in intravascular pressure. Activation of the voltage-dependent Ca2+ channel, Cav1.2, leads to Ca2+ influx and consequently arterial tone development and vasoconstriction. Unique among Ca2+ channels, the vascular Cav3.2 T-type channel mediates feedback inhibition of arterial tone-and therefore causes vasodilation-of resistance arteries by virtue of functional association with hyperpolarizing ion channels. During aging, several signaling modalities are altered along with vascular remodeling. There is a growing appreciation of how calcium channel signaling alters with aging and how this may affect vascular function. Here, we discuss key determinants of arterial tone development and the crucial involvement of Ca2+ channels. We next provide an updated view of key changes in Ca2+ channel expression and function during aging and how these affect vascular function. Further, this article synthesizes new questions in light of recent developments. We hope that these questions will outline a roadmap for new research, which, undoubtedly, will unravel a more comprehensive picture of arterial tone dysfunction during aging.
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Affiliation(s)
- Osama F. Harraz
- Dept. of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT, 05405 USA,Corresponding author. (O.F. Harraz)
| | - Lars Jørn Jensen
- Pathobiological Sciences, Dept. of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg C, Denmark
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10
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Testai L, Citi V, Martelli A, Brogi S, Calderone V. Role of hydrogen sulfide in cardiovascular ageing. Pharmacol Res 2020; 160:105125. [PMID: 32783975 DOI: 10.1016/j.phrs.2020.105125] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/17/2020] [Accepted: 08/05/2020] [Indexed: 12/11/2022]
Abstract
Cardiovascular diseases are the main cause of morbidity and mortality in the Western society and ageing is a relevant non-modifiable risk factor. Morphological and functional alterations at endothelial level represent first events of ageing, inevitably followed by vascular dysfunction and consequent atherosclerosis that deeply influences cardiovascular health. Indeed, myocardial hypertrophy and fibrosis typically occur and contribute to compromise overall cardiac output. As regards the intracellular molecular mechanisms involved in the cardiovascular ageing, an intricate network is emerging, revealing a role for many mediators, including SIRT1/AMPK/PCG1α pathway, anti-oxidants factors (i.e. Nrf-2 and FOXOs) and pro-inflammatory cytokines. Thus, the search for pharmacological and non-pharmacological strategies that can promote a "healthy ageing", in order to slow down age-related machinery, are currently an exciting challenge for the biomedical research. Interestingly, hydrogen sulfide (H2S) has been recently recognized as a new player capable to influence intracellular machinery involved in ageing and then it is view as a potential target for preventing cardiovascular diseases. Therefore, this review is focused on the role of H2S in cardiovascular ageing, and on the evidence of the relationship between progressive decline in endogenous H2S levels and the onset of various cardiovascular age-related diseases.
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Affiliation(s)
- Lara Testai
- Department of Pharmacy, University of Pisa, via Bonanno, 6-56120, Pisa, Italy; Interdepartmental Research Centre of Ageing, Biology and Pathology, University of Pisa, 56120, Pisa, Italy; Interdepartmental Research Centre "Nutraceuticals and Food for Health (NUTRAFOOD)", University of Pisa, 56120, Pisa, Italy.
| | - Valentina Citi
- Department of Pharmacy, University of Pisa, via Bonanno, 6-56120, Pisa, Italy
| | - Alma Martelli
- Department of Pharmacy, University of Pisa, via Bonanno, 6-56120, Pisa, Italy; Interdepartmental Research Centre of Ageing, Biology and Pathology, University of Pisa, 56120, Pisa, Italy; Interdepartmental Research Centre "Nutraceuticals and Food for Health (NUTRAFOOD)", University of Pisa, 56120, Pisa, Italy
| | - Simone Brogi
- Department of Pharmacy, University of Pisa, via Bonanno, 6-56120, Pisa, Italy
| | - Vincenzo Calderone
- Department of Pharmacy, University of Pisa, via Bonanno, 6-56120, Pisa, Italy; Interdepartmental Research Centre of Ageing, Biology and Pathology, University of Pisa, 56120, Pisa, Italy; Interdepartmental Research Centre "Nutraceuticals and Food for Health (NUTRAFOOD)", University of Pisa, 56120, Pisa, Italy
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11
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Reed JT, Pareek T, Sriramula S, Pabbidi MR. Aging influences cerebrovascular myogenic reactivity and BK channel function in a sex-specific manner. Cardiovasc Res 2020; 116:1372-1385. [PMID: 31738403 DOI: 10.1093/cvr/cvz314] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/06/2019] [Accepted: 11/15/2019] [Indexed: 11/14/2022] Open
Abstract
AIMS The myogenic reactivity of the middle cerebral arteries (MCA) protects the brain by altering the diameter in response to changes in lumen pressure. Large conductance potassium (BK) channels are known to regulate the myogenic reactivity, yet, it is not clear how aging alters the myogenic reactivity via the BK channel in males and females. Thus, we hypothesize that age-associated changes in BK channel subunits modulate the myogenic reactivity in a sex-specific manner. METHODS AND RESULTS We used vascular reactivity, patch-clamp, and biochemical methods to measure myogenic reactivity, BK channel function, and expression, respectively in cerebral vessels of adult and aged male and female Sprague Dawley rats. Our results suggest that aging and ovariectomy (OVX) exaggerated the myogenic reactivity of MCA in females but attenuated it in males. Aging induced outward eutrophic remodelling in females but inward hypertrophic remodelling in males. Aging decreased total, Kv, BK channel currents, and spontaneous transient outward currents (STOC) in vascular smooth muscle cells isolated from females, but not in males. Aging increased BKα subunit mRNA and protein both in males and females. However, aging decreased BKβ1 subunit protein and mRNA in females only. In males, BKβ1 mRNA is increased, but protein is decreased. Iberiotoxin-induced MCA constriction is lower in aged females but higher in aged males. Activation of BKα (10 µM NS1619) and BKβ1 (10 µM S-Equol) subunits failed to increase STOCs and were unable to decrease the myogenic reactivity of MCA in aged female but not in aged male rats. OVX decreased, but chronic supplementation of oestradiol restored BK channel expression and function. CONCLUSION Overall our results suggest that aging or OVX-associated downregulation of the BKβ1 expression and function in females results in exaggerated myogenic reactivity of MCA. However, age-associated increase in BK channel function in males attenuated myogenic reactivity of MCA.
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Affiliation(s)
- Joseph T Reed
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA
| | - Tanya Pareek
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA
| | - Srinivas Sriramula
- Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC 27834-4300, USA
| | - Mallikarjuna R Pabbidi
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA
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12
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Wang XL, Lu T, Sun X, Lee HC. Membrane trafficking of large conductance Ca 2+- and voltage-activated K + (BK) channels is regulated by Rab4 GTPase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118646. [PMID: 31926210 DOI: 10.1016/j.bbamcr.2020.118646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/26/2019] [Accepted: 01/06/2020] [Indexed: 12/28/2022]
Abstract
The large conductance voltage- and Ca2+-activated K+ (BK) channel is a major ionic determinant of vascular tone, vasodilation, and blood pressure. The activity of BK channels is regulated in part by membrane presentation. Rab GTPase (Rab) regulates important cellular processes, including ion channel membrane trafficking. We hypothesize that Rab4a participates in the regulation of BK channel α-subunit (BK-α) membrane trafficking. We found that vascular BK-α interacts physically with Rab4a. Co-expression of dominant-negative Rab4a reduced BK-α surface expression, whereas that of constitutively-active Rab4a augmented BK-α surface presentation. These novel findings suggest that vascular BK channel membrane expression is regulated by Rab4a through channel membrane trafficking.
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Affiliation(s)
- Xiao-Li Wang
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
| | - Tong Lu
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Xiaojing Sun
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Hon-Chi Lee
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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13
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BK Ca ( Slo) Channel Regulates Mitochondrial Function and Lifespan in Drosophila melanogaster. Cells 2019; 8:cells8090945. [PMID: 31438578 PMCID: PMC6770356 DOI: 10.3390/cells8090945] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/13/2019] [Accepted: 08/20/2019] [Indexed: 12/20/2022] Open
Abstract
BKCa channels, originally discovered in Drosophila melanogaster as slowpoke (slo), are recognized for their roles in cellular and organ physiology. Pharmacological approaches implicated BKCa channels in cellular and organ protection possibly for their ability to modulate mitochondrial function. However, the direct role of BKCa channels in regulating mitochondrial structure and function is not deciphered. Here, we demonstrate that BKCa channels are present in fly mitochondria, and slo mutants show structural and functional defects in mitochondria. slo mutants display an increase in reactive oxygen species and the modulation of ROS affected their survival. We also found that the absence of BKCa channels reduced the lifespan of Drosophila, and overexpression of human BKCa channels in flies extends life span in males. Our study establishes the presence of BKCa channels in mitochondria of Drosophila and ascertains its novel physiological role in regulating mitochondrial structural and functional integrity, and lifespan.
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Dogan MF, Arslan SO, Yildiz O, Kurtoglu M, Parlar A. Propofol-Induced Vasodilation in Human Internal Mammary Artery: Role of Potassium Channels. J Cardiothorac Vasc Anesth 2019; 33:2183-2191. [DOI: 10.1053/j.jvca.2018.12.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Indexed: 12/13/2022]
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McGarr GW, Fujii N, Muia CM, Nishiyasu T, Kenny GP. Separate and combined effects of K Ca and K ATP channel blockade with NOS inhibition on cutaneous vasodilation and sweating in older men during heat stress. Am J Physiol Regul Integr Comp Physiol 2019; 317:R113-R120. [PMID: 31091157 DOI: 10.1152/ajpregu.00075.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our objective in this study was to examine the separate and combined effects of potassium (K+) channels and nitric oxide synthase (NOS) on cutaneous vasodilation and sweating in older men during rest and exercise in the heat. In 13 habitually active men (61 ± 4 yr), cutaneous vascular conductance and local sweat rate were assessed at six dorsal forearm skin sites continuously perfused with either 1) lactated Ringer (control), 2) 10 mM NG-nitro-l-arginine methyl ester (l-NAME, NOS inhibitor), 3) 50 mM tetraethylammonium (TEA; Ca2+-activated K+ channel blocker), 4) 5 mM glybenclamide (GLY; ATP-sensitive K+ channel blocker), 5) 50 mM TEA + 10 mM l-NAME, and 6) 5 mM GLY + 10 mM l-NAME via microdialysis. Participants rested in non-heat stress (25°C) and heat stress (35°C) conditions for ∼60 min each, followed by 50 min of moderate-intensity cycling (∼55% V̇o2peak) and 30 min of recovery in the heat. During rest and exercise in the heat, l-NAME, TEA + l-NAME, and GLY + l-NAME attenuated CVC relative to control (all P ≤ 0.05), although l-NAME was not different from TEA + l-NAME or GLY + l-NAME (all P > 0.05). TEA attenuated CVC during rest, whereas GLY attenuated CVC during exercise (both P ≤ 0.05). Additionally, whereas neither l-NAME nor TEA altered sweating throughout the protocol (all P > 0.05), combined TEA + l-NAME attenuated sweating during exercise in the heat (P ≤ 0.05). We conclude that in habitually active older men blockade of KCa and KATP channels attenuates cutaneous vasodilation during rest and exercise in the heat, respectively, and these effects are NOS dependent. Furthermore, combined NOS inhibition and KCa channel blockade attenuates sweating during exercise in the heat.
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Affiliation(s)
- Gregory W McGarr
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada
| | - Naoto Fujii
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada.,Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba City , Japan
| | - Caroline M Muia
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba , Tsukuba City , Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa, Ontario , Canada
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Strickland M, Yacoubi-Loueslati B, Bouhaouala-Zahar B, Pender SLF, Larbi A. Relationships Between Ion Channels, Mitochondrial Functions and Inflammation in Human Aging. Front Physiol 2019; 10:158. [PMID: 30881309 PMCID: PMC6405477 DOI: 10.3389/fphys.2019.00158] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/08/2019] [Indexed: 12/19/2022] Open
Abstract
Aging is often associated with a loss of function. We believe aging to be more an adaptation to the various, and often continuous, stressors encountered during life in order to maintain overall functionality of the systems. The maladaptation of a system during aging may increase the susceptibility to diseases. There are basic cellular functions that may influence and/or are influenced by aging. Mitochondrial function is amongst these. Their presence in almost all cell types makes of these valuable targets for interventions to slow down or even reserve signs of aging. In this review, the role of mitochondria and essential physiological regulators of mitochondria and cellular functions, ion channels, will be discussed in the context of human aging. The origins of inflamm-aging, associated with poor clinical outcomes, will be linked to mitochondria and ion channel biology.
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Affiliation(s)
- Marie Strickland
- Singapore Immunology Network, Agency for Science Technology and Research, Singapore, Singapore
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Besma Yacoubi-Loueslati
- Laboratory of Mycology, Pathologies and Biomarkers, Department of Biology, Faculty of Sciences, University Tunis El Manar, Tunis, Tunisia
| | - Balkiss Bouhaouala-Zahar
- Laboratory of Venoms and Therapeutic Molecules, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
- Medical School of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Sylvia L. F. Pender
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- Chinese University of Hong Kong – University of Southampton Joint Lab for Stem Cell and Regenerative Medicine, Hong Kong, China
| | - Anis Larbi
- Singapore Immunology Network, Agency for Science Technology and Research, Singapore, Singapore
- Department of Biology, Faculty of Sciences, University Tunis El Manar, Tunis, Tunisia
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Geriatrics Division, Department of Medicine, Research Center on Aging, University of Sherbrooke, Sherbrooke, QC, Canada
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Patel NH, Johannesen J, Shah K, Goswami SK, Patel NJ, Ponnalagu D, Kohut AR, Singh H. Inhibition of BK Ca negatively alters cardiovascular function. Physiol Rep 2018; 6:e13748. [PMID: 29932499 PMCID: PMC6014461 DOI: 10.14814/phy2.13748] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/15/2018] [Accepted: 05/28/2018] [Indexed: 12/19/2022] Open
Abstract
Large conductance calcium and voltage-activated potassium channels (BKCa ) are transmembrane proteins, ubiquitously expressed in the majority of organs, and play an active role in regulating cellular physiology. In the heart, BKCa channels are known to play a role in regulating the heart rate and protect it from ischemia-reperfusion injury. In vascular smooth muscle cells, the opening of BKCa channels results in membrane hyperpolarization which eventually results in vasodilation mediated by a reduction in Ca2+ influx due to the closure of voltage-dependent Ca2+ channels. Ex vivo studies have shown that BKCa channels play an active role in the regulation of the function of the majority of blood vessels. However, in vivo role of BKCa channels in cardiovascular function is not completely deciphered. Here, we have evaluated the rapid in vivo role of BKCa channels in regulating the cardiovascular function by using two well-established, rapid-acting, potent blockers, paxilline and iberiotoxin. Our results show that BKCa channels are actively involved in regulating the heart rate, the function of the left and right heart as well as major vessels. We also found that the effect on BKCa channels by blockers is completely reversible, and hence, BKCa channels can be exploited as potential targets for clinical applications for modulating heart rate and cardiac contractility.
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Affiliation(s)
- Nishi H. Patel
- Department of Internal MedicineDrexel University College of MedicinePhiladelphiaPennsylvania
| | - Justin Johannesen
- Department of Internal MedicineDrexel University College of MedicinePhiladelphiaPennsylvania
| | - Kajol Shah
- Department of Pharmacology and PhysiologyDrexel University College of MedicinePhiladelphiaPennsylvania
| | - Sumanta K. Goswami
- Department of Pharmacology and PhysiologyDrexel University College of MedicinePhiladelphiaPennsylvania
| | - Neel J. Patel
- Department of Internal MedicineDrexel University College of MedicinePhiladelphiaPennsylvania
| | - Devasena Ponnalagu
- Department of Pharmacology and PhysiologyDrexel University College of MedicinePhiladelphiaPennsylvania
| | - Andrew R. Kohut
- Penn Heart and Vascular CenterUniversity of PennsylvaniaPhiladelphiaPennsylvania
| | - Harpreet Singh
- Department of Pharmacology and PhysiologyDrexel University College of MedicinePhiladelphiaPennsylvania
- Division of CardiologyDrexel University College of MedicinePhiladelphiaPennsylvania
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Dopico AM, Bukiya AN, Jaggar JH. Calcium- and voltage-gated BK channels in vascular smooth muscle. Pflugers Arch 2018; 470:1271-1289. [PMID: 29748711 DOI: 10.1007/s00424-018-2151-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 04/27/2018] [Indexed: 02/04/2023]
Abstract
Ion channels in vascular smooth muscle regulate myogenic tone and vessel contractility. In particular, activation of calcium- and voltage-gated potassium channels of large conductance (BK channels) results in outward current that shifts the membrane potential toward more negative values, triggering a negative feed-back loop on depolarization-induced calcium influx and SM contraction. In this short review, we first present the molecular basis of vascular smooth muscle BK channels and the role of subunit composition and trafficking in the regulation of myogenic tone and vascular contractility. BK channel modulation by endogenous signaling molecules, and paracrine and endocrine mediators follows. Lastly, we describe the functional changes in smooth muscle BK channels that contribute to, or are triggered by, common physiological conditions and pathologies, including obesity, diabetes, and systemic hypertension.
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Affiliation(s)
- Alex M Dopico
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St., Memphis, TN, 38163, USA.
| | - Anna N Bukiya
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St., Memphis, TN, 38163, USA
| | - Jonathan H Jaggar
- Department of Physiology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, USA
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19
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Badin JK, Bruning RS, Sturek M. Effect of metabolic syndrome and aging on Ca 2+ dysfunction in coronary smooth muscle and coronary artery disease severity in Ossabaw miniature swine. Exp Gerontol 2018; 108:247-255. [PMID: 29730333 DOI: 10.1016/j.exger.2018.04.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/19/2018] [Accepted: 04/29/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND Metabolic syndrome (MetS) and aging are prevalent risk factors for coronary artery disease (CAD) and contribute to the etiology of CAD, including dysregulation of Ca2+ handling mechanisms in coronary smooth muscle (CSM). The current study tested the hypothesis that CAD severity and CSM Ca2+ dysregulation were different in MetS-induced CAD compared to aging-induced CAD. METHODS Young (2.5 ± 0.2 years) and old (8.8 ± 1.2 years) Ossabaw miniature swine were fed an atherogenic diet for 11 months to induce MetS and were compared to lean age-matched controls. The metabolic profile was confirmed by body weight, plasma cholesterol and triglycerides, and intravenous glucose tolerance test. CAD was measured with intravascular ultrasound and histology. Intracellular Ca2+ ([Ca2+]i) was assessed with fura-2 imaging. RESULTS CAD severity was similar between MetS young and lean old swine, with MetS old swine exhibiting the most severe CAD. Compared to CSM [Ca2+]i handling in lean young, the MetS young and lean old swine exhibited increased sarcoplasmic reticulum Ca2+ store release, increased Ca2+ influx through voltage-gated Ca2+ channels, and attenuated sarco-endoplasmic reticulum Ca2+ ATPase activity. MetS old and MetS young swine had similar Ca2+ dysregulation. CONCLUSIONS Ca2+ dysregulation, mainly the SR Ca2+ store, in CSM is more pronounced in lean old swine, which is indicative of mild, proliferative CAD. MetS old and MetS young swine exhibit Ca2+ dysfunction that is typical of late, severe disease. The more advanced, complex plaques in MetS old swine suggest that the "aging milieu" potentiates effects of Ca2+ handling dysfunction in CAD.
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Affiliation(s)
- Jill K Badin
- Department of Cellular & Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202-5120, United States
| | - Rebecca S Bruning
- Department of Cellular & Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202-5120, United States; RTI International, Global Health Technologies, Research Triangle Park, NC 27709, United States
| | - Michael Sturek
- Department of Cellular & Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202-5120, United States.
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20
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Huertas A, Guignabert C, Barberà JA, Bärtsch P, Bhattacharya J, Bhattacharya S, Bonsignore MR, Dewachter L, Dinh-Xuan AT, Dorfmüller P, Gladwin MT, Humbert M, Kotsimbos T, Vassilakopoulos T, Sanchez O, Savale L, Testa U, Wilkins MR. Pulmonary vascular endothelium: the orchestra conductor in respiratory diseases. Eur Respir J 2018; 51:13993003.00745-2017. [DOI: 10.1183/13993003.00745-2017] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 02/03/2018] [Indexed: 12/15/2022]
Abstract
The European Respiratory Society (ERS) Research Seminar entitled “Pulmonary vascular endothelium: orchestra conductor in respiratory diseases - highlights from basic research to therapy” brought together international experts in dysfunctional pulmonary endothelium, from basic science to translational medicine, to discuss several important aspects in acute and chronic lung diseases. This review will briefly sum up the different topics of discussion from this meeting which was held in Paris, France on October 27–28, 2016. It is important to consider that this paper does not address all aspects of endothelial dysfunction but focuses on specific themes such as: 1) the complex role of the pulmonary endothelium in orchestrating the host response in both health and disease (acute lung injury, chronic obstructive pulmonary disease, high-altitude pulmonary oedema and pulmonary hypertension); and 2) the potential value of dysfunctional pulmonary endothelium as a target for innovative therapies.
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21
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BKCa channel activity and vascular contractility alterations with hypertension and aging via β1 subunit promoter methylation in mesenteric arteries. Hypertens Res 2017; 41:96-103. [DOI: 10.1038/hr.2017.96] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/12/2017] [Accepted: 07/28/2017] [Indexed: 01/14/2023]
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22
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Xu X, Wang B, Ren C, Hu J, Greenberg DA, Chen T, Xie L, Jin K. Recent Progress in Vascular Aging: Mechanisms and Its Role in Age-related Diseases. Aging Dis 2017; 8:486-505. [PMID: 28840062 PMCID: PMC5524810 DOI: 10.14336/ad.2017.0507] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/07/2017] [Indexed: 01/13/2023] Open
Abstract
As with many age-related diseases including vascular dysfunction, age is considered an independent and crucial risk factor. Complicated alterations of structure and function in the vasculature are linked with aging hence, understanding the underlying mechanisms of age-induced vascular pathophysiological changes holds possibilities for developing clinical diagnostic methods and new therapeutic strategies. Here, we discuss the underlying molecular mediators that could be involved in vascular aging, e.g., the renin-angiotensin system and pro-inflammatory factors, metalloproteinases, calpain-1, monocyte chemoattractant protein-1 (MCP-1) and TGFβ-1 as well as the potential roles of testosterone and estrogen. We then relate all of these to clinical manifestations such as vascular dementia and stroke in addition to reviewing the existing clinical measurements and potential interventions for age-related vascular dysfunction.
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Affiliation(s)
- Xianglai Xu
- 1Zhongshan Hospital, Fudan University, Shanghai 200032, China.,2Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, TX 76107, USA
| | - Brian Wang
- 2Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, TX 76107, USA
| | - Changhong Ren
- 2Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, TX 76107, USA.,4Institute of Hypoxia Medicine, Xuanwu Hospital, Capital Medical University. Beijing, China
| | - Jiangnan Hu
- 2Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, TX 76107, USA
| | | | - Tianxiang Chen
- 6Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Liping Xie
- 3Department of Urology, the First Affiliated Hospital, Zhejiang University, Zhejiang Province, China
| | - Kunlin Jin
- 2Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, TX 76107, USA
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23
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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Kuntamallappanavar G, Bisen S, Bukiya AN, Dopico AM. Differential distribution and functional impact of BK channel beta1 subunits across mesenteric, coronary, and different cerebral arteries of the rat. Pflugers Arch 2016; 469:263-277. [PMID: 28012000 DOI: 10.1007/s00424-016-1929-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/06/2016] [Accepted: 12/12/2016] [Indexed: 12/12/2022]
Abstract
Large conductance, Ca2+i- and voltage-gated K+ (BK) channels regulate myogenic tone and, thus, arterial diameter. In smooth muscle (SM), BK channels include channel-forming α and auxiliary β1 subunits. BK β1 increases the channel's Ca2+ sensitivity, allowing BK channels to negatively feedback on depolarization-induced Ca2+ entry, oppose SM contraction and favor vasodilation. Thus, endothelial-independent vasodilation can be evoked though targeting of SM BK β1 by endogenous ligands, including lithocholate (LCA). Here, we investigated the expression of BK β1 across arteries of the cerebral and peripheral circulations, and the contribution of such expression to channel function and BK β1-mediated vasodilation. Data demonstrate that endothelium-independent, BK β1-mediated vasodilation by LCA is larger in coronary (CA) and basilar (BA) arteries than in anterior cerebral (ACA), middle cerebral (MCA), posterior cerebral (PCA), and mesenteric (MA) arteries, all arterial segments having a similar diameter. Thus, differential dilation occurs in extracranial arteries which are subjected to similar vascular pressure (CA vs. MA) and in arteries that irrigate different brain regions (BA vs. ACA, MCA, and PCA). SM BK channels from BA and CA displayed increased basal activity and LCA responses, indicating increased BK β1 functional presence. Indeed, in the absence of detectable changes in BK α, BA and CA myocytes showed an increased location of BK β1 in the plasmalemma/subplasmalemma. Moreover, these myocytes distinctly showed increased BK β1 messenger RNA (mRNA) levels. Supporting a major role of enhanced BK β1 transcripts in artery dilation, LCA-induced dilation of MCA transfected with BK β1 complementary DNA (cDNA) was as high as LCA-induced dilation of untransfected BA or CA.
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Affiliation(s)
- Guruprasad Kuntamallappanavar
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St, Memphis, TN, 38103, USA
| | - Shivantika Bisen
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St, Memphis, TN, 38103, USA
| | - Anna N Bukiya
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St, Memphis, TN, 38103, USA
| | - Alex M Dopico
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St, Memphis, TN, 38103, USA.
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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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Potassium Channels in Regulation of Vascular Smooth Muscle Contraction and Growth. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:89-144. [PMID: 28212804 DOI: 10.1016/bs.apha.2016.07.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Potassium channels importantly contribute to the regulation of vascular smooth muscle (VSM) contraction and growth. They are the dominant ion conductance of the VSM cell membrane and importantly determine and regulate membrane potential. Membrane potential, in turn, regulates the open-state probability of voltage-gated Ca2+ channels (VGCC), Ca2+ influx through VGCC, intracellular Ca2+, and VSM contraction. Membrane potential also affects release of Ca2+ from internal stores and the Ca2+ sensitivity of the contractile machinery such that K+ channels participate in all aspects of regulation of VSM contraction. Potassium channels also regulate proliferation of VSM cells through membrane potential-dependent and membrane potential-independent mechanisms. VSM cells express multiple isoforms of at least five classes of K+ channels that contribute to the regulation of contraction and cell proliferation (growth). This review will examine the structure, expression, and function of large conductance, Ca2+-activated K+ (BKCa) channels, intermediate-conductance Ca2+-activated K+ (KCa3.1) channels, multiple isoforms of voltage-gated K+ (KV) channels, ATP-sensitive K+ (KATP) channels, and inward-rectifier K+ (KIR) channels in both contractile and proliferating VSM cells.
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Li N, Liu B, Xiang S, Shi L. Similar enhancement of BK(Ca) channel function despite different aerobic exercise frequency in aging cerebrovascular myocytes. Physiol Res 2016; 65:447-59. [PMID: 27070745 DOI: 10.33549/physiolres.933111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Aerobic exercise showed beneficial influence on cardiovascular systems in aging, and mechanisms underlying vascular adaption remain unclear. Large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels play critical roles in regulating cellular excitability and vascular tone. This study determined the effects of aerobic exercise on aging-associated functional changes in BK(Ca) channels in cerebrovascular myocytes, Male Wistar rats aged 20-22 months were randomly assigned to sedentary (O-SED), low training frequency (O-EXL), and high training frequency group (O-EXH). Young rats were used as control. Compared to young rats, whole-cell BK(Ca) current was decreased, and amplitude of spontaneous transient outward currents were reduced. The open probability and Ca(2+)/voltage sensitivity of single BK(Ca) channel were declined in O-SED, accompanied with a reduction of tamoxifen-induced BK(Ca) activation; the mean open time of BK(Ca) channels was shortened whereas close time was prolonged. Aerobic exercise training markedly alleviated the aging-associated decline independent of training frequency. Exercise three times rather than five times weekly may be a time and cost-saving training volume required to offer beneficial effects to offset the functional declines of BK(Ca) during aging.
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Affiliation(s)
- N Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China, Department of Exercise Physiology, Beijing Sport University, Beijing, China.
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Krishnamoorthy-Natarajan G, Koide M. BK Channels in the Vascular System. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 128:401-38. [PMID: 27238270 DOI: 10.1016/bs.irn.2016.03.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autoregulation of blood flow is essential for the preservation of organ function to ensure continuous supply of oxygen and essential nutrients and removal of metabolic waste. This is achieved by controlling the diameter of muscular arteries and arterioles that exhibit a myogenic response to changes in arterial blood pressure, nerve activity and tissue metabolism. Large-conductance voltage and Ca(2+)-dependent K(+) channels (BK channels), expressed exclusively in smooth muscle cells (SMCs) in the vascular wall of healthy arteries, play a critical role in regulating the myogenic response. Activation of BK channels by intracellular, local, and transient ryanodine receptor-mediated "Ca(2+) sparks," provides a hyperpolarizing influence on the SMC membrane potential thereby decreasing the activity of voltage-dependent Ca(2+) channels and limiting Ca(2+) influx to promote SMC relaxation and vasodilation. The BK channel α subunit, a large tetrameric protein with each monomer consisting of seven-transmembrane domains, a long intracellular C-terminal tail and an extracellular N-terminus, associates with the β1 and γ subunits in vascular SMCs. The BK channel is regulated by factors originating within the SMC or from the endothelium, perivascular nerves and circulating blood, that significantly alter channel gating properties, Ca(2+) sensitivity and expression of the α and/or β1 subunit. The BK channel thus serves as a central receiving dock that relays the effects of the changes in several such concomitant autocrine and paracrine factors and influences cardiovascular health. This chapter describes the primary mechanism of regulation of myogenic response by BK channels and the alterations to this mechanism wrought by different vasoactive mediators.
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Affiliation(s)
| | - M Koide
- University of Vermont, Burlington, VT, United States
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Fujii N, Meade RD, Minson CT, Brunt VE, Boulay P, Sigal RJ, Kenny GP. Cutaneous blood flow during intradermal NO administration in young and older adults: roles for calcium-activated potassium channels and cyclooxygenase? Am J Physiol Regul Integr Comp Physiol 2016; 310:R1081-7. [PMID: 27053645 DOI: 10.1152/ajpregu.00041.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/30/2016] [Indexed: 01/22/2023]
Abstract
Nitric oxide (NO) increases cutaneous blood flow; however, the underpinning mechanism(s) remains to be elucidated. We hypothesized that the cutaneous blood flow response during intradermal administration of sodium nitroprusside (SNP, a NO donor) is regulated by calcium-activated potassium (KCa) channels and cyclooxygenase (COX) in young adults. We also hypothesized that these contributions are diminished in older adults given that aging can downregulate KCa channels and reduce COX-derived vasodilator prostanoids. In 10 young (23 ± 5 yr) and 10 older (54 ± 4 yr) adults, cutaneous vascular conductance (CVC) was measured at four forearm skin sites infused with 1) Ringer (Control), 2) 50 mM tetraethylammonium (TEA), a nonspecific KCa channel blocker, 3) 10 mM ketorolac, a nonspecific COX inhibitor, or 4) 50 mM TEA + 10 mM ketorolac via intradermal microdialysis. All skin sites were coinfused with incremental doses of SNP (0.005, 0.05, 0.5, 5, and 50 mM each for 25 min). During SNP administration, CVC was similar at the ketorolac site (0.005-50 mM, all P > 0.05) relative to Control, but lower at the TEA and TEA + ketorolac sites (0.005-0.05 mM, all P < 0.05) in young adults. In older adults, ketorolac increased CVC relative to Control during 0.005-0.05 mM SNP administration (all P < 0.05), but this increase was not observed when TEA was coadministered (all P > 0.05). Furthermore, TEA alone did not modulate CVC during any concentration of SNP administration in older adults (all P > 0.05). We show that during low-dose NO administration (e.g., 0.005-0.05 mM), KCa channels contribute to cutaneous blood flow regulation in young adults; however, in older adults, COX inhibition increases cutaneous blood flow through a KCa channel-dependent mechanism.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | | | - Vienna E Brunt
- Department of Human Physiology, The University of Oregon, Eugene, Oregon
| | - 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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Su JB. Vascular endothelial dysfunction and pharmacological treatment. World J Cardiol 2015; 7:719-741. [PMID: 26635921 PMCID: PMC4660468 DOI: 10.4330/wjc.v7.i11.719] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/23/2015] [Accepted: 09/18/2015] [Indexed: 02/06/2023] Open
Abstract
The endothelium exerts multiple actions involving regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammatory and immunological reactions and cell growth. Alterations of one or more such actions may cause vascular endothelial dysfunction. Different risk factors such as hypercholesterolemia, homocystinemia, hyperglycemia, hypertension, smoking, inflammation, and aging contribute to the development of endothelial dysfunction. Mechanisms underlying endothelial dysfunction are multiple, including impaired endothelium-derived vasodilators, enhanced endothelium-derived vasoconstrictors, over production of reactive oxygen species and reactive nitrogen species, activation of inflammatory and immune reactions, and imbalance of coagulation and fibrinolysis. Endothelial dysfunction occurs in many cardiovascular diseases, which involves different mechanisms, depending on specific risk factors affecting the disease. Among these mechanisms, a reduction in nitric oxide (NO) bioavailability plays a central role in the development of endothelial dysfunction because NO exerts diverse physiological actions, including vasodilation, anti-inflammation, antiplatelet, antiproliferation and antimigration. Experimental and clinical studies have demonstrated that a variety of currently used or investigational drugs, such as angiotensin-converting enzyme inhibitors, angiotensin AT1 receptors blockers, angiotensin-(1-7), antioxidants, beta-blockers, calcium channel blockers, endothelial NO synthase enhancers, phosphodiesterase 5 inhibitors, sphingosine-1-phosphate and statins, exert endothelial protective effects. Due to the difference in mechanisms of action, these drugs need to be used according to specific mechanisms underlying endothelial dysfunction of the disease.
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Age-related changes of inactivating BK channels in rat dorsal root ganglion neurons. J Neurol Sci 2015; 358:138-45. [PMID: 26341151 DOI: 10.1016/j.jns.2015.08.1526] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 08/22/2015] [Accepted: 08/22/2015] [Indexed: 11/21/2022]
Abstract
The large-conductance, voltage- and Ca(2+)-activated K(+) channels (termed BK) are associated with age-related dysfunctions or diseases. Previously, with our colleagues, we reported that the rβ2-associated inactivating BK (BKi) channels play an essential role in rat dorsal root ganglion (DRG) neurons. However, the age-dependent changes in BKi channels are still elusive. Here, we identify three types of BK channels in small DRG neurons, the single exponential BKi, the double exponential BKi and the non-inactivating BK. Interestingly, compared to the increased occurrence of the non-inactivating BK, the presence of BKi channels declined with age. Furthermore, the peak amplitude of the single exponential BKi current increased from infancy to youth, but decreased from youth to old age. The inactivation time constant, however, did not change with age. The double exponential BKi also displayed age-related change in current amplitude with an intricate kinetics. Physiologically, the decay speed of the action potential was significantly increased in Youth, which correlated with the change of current amplitude of BKi channels. Collectively, these results reveal an age-related change pattern of BKi channels in small DRG neurons, providing potential mechanistic clues for different susceptibility to sensation in different ages.
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Boerman EM, Segal SS. Depressed perivascular sensory innervation of mouse mesenteric arteries with advanced age. J Physiol 2015; 594:2323-38. [PMID: 26010764 DOI: 10.1113/jp270710] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/15/2015] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS The dilatory role for sensory innervation of mesenteric arteries (MAs) is impaired in Old (∼24 months) versus Young (∼4 months) mice. We investigated the nature of this impairment in isolated pressurized MAs. With perivascular sensory nerve stimulation, dilatation and inhibition of sympathetic vasoconstriction observed in Young MAs were lost in Old MAs along with impaired dilatation to calcitonin gene-related peptide (CGRP). Inhibiting NO and prostaglandin synthesis increased CGRP EC50 in Young and Old MAs. Endothelial denudation attenuated dilatation to CGRP in Old MAs yet enhanced dilatation to CGRP in Young MAs while abolishing all dilatations to ACh. In Old MAs, sensory nerve density was reduced and RAMP1 (CGRP receptor component) associated with nuclear regions of endothelial cells in a manner not seen in Young MAs or in smooth muscle cells of either age. With advanced age, loss of dilatory signalling mediated through perivascular sensory nerves may compromise perfusion of visceral organs. ABSTRACT Vascular dysfunction and sympathetic nerve activity increase with advancing age. In the gut, blood flow is governed by perivascular sensory and sympathetic nerves but little is known of how their functional role is affected by advanced age. We tested the hypothesis that functional sensory innervation of mesenteric arteries (MAs) is impaired for Old (24 months) versus Young (4 months) C57BL/6 male mice. In cannulated pressurized MAs preconstricted 50% with noradrenaline and treated with guanethidine (to inhibit sympathetic neurotransmission), perivascular nerve stimulation (PNS) evoked dilatation in Young but not Old MAs while dilatations to ACh were not different between age groups. In Young MAs, capsaicin (to inhibit sensory neurotransmission) blocked dilatation and increased constriction during PNS. With no difference in efficacy, the EC50 of CGRP as a vasodilator was ∼6-fold greater in Old versus Young MAs. Inhibiting nitric oxide (l-NAME) and prostaglandin (indomethacin) synthesis increased CGRP EC50 in both age groups. Endothelial denudation reduced the efficacy of dilatation to CGRP by ∼30% in Old MAs yet increased this efficacy ∼15% in Young MAs while all dilatations to ACh were abolished. Immunolabelling revealed reduced density of sensory (CGRP) but not sympathetic (tyrosine hydroxylase) innervation for Old versus Young MAs. Whereas the distribution of CGRP receptor proteins was similar in SMCs, RAMP1 associated with nuclear regions of endothelial cells of Old but not Young MAs. With advanced age, the loss of sensory nerve function and diminished effectiveness of CGRP as a vasodilator is multifaceted and may adversely affect splanchnic perfusion.
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Affiliation(s)
- Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA.,Dalton Cardiovascular Research Center, Columbia, MO, 65211, USA
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Xu H, Garver H, Fernandes R, Galligan JJ, Fink GD. Altered L-type Ca2+ channel activity contributes to exacerbated hypoperfusion and mortality in smooth muscle cell BK channel-deficient septic mice. Am J Physiol Regul Integr Comp Physiol 2014; 307:R138-48. [PMID: 24829499 DOI: 10.1152/ajpregu.00117.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We determined the contribution of vascular large conductance Ca2+-activated K+ (BK) and L-type Ca2+ channel dysregulation to exaggerated mortality in cecal ligation/puncture (CLP)-induced septic BK channel β1-subunit knockout (BK β1-KO, smooth muscle specific) mice. CLP-induced hemodynamic changes and mortality were assessed over 7 days in wild-type (WT) and BK β1-KO mice that were either untreated, given volume resuscitation (saline), or saline + calcium channel blocker nicardipine. Some mice were euthanized 24 h post-CLP to measure tissue injury and vascular and immune responses. CLP-induced hypotension was similar in untreated WT and BK β1-KO mice, but BK β1-KO mice died sooner. At 24 h post-CLP (mortality latency in BK β1-KO mice), untreated CLP-BK β1-KO mice showed more severe hypothermia, lower tissue perfusion, polymorphonuclear neutrophil infiltration-independent severe intestinal necrosis, and higher serum cytokine levels than CLP-WT mice. Saline resuscitation improved survival in CLP-WT but not CLP-BK β1-KO mice. Saline + nicardipine-treated CLP-BK β1-KO mice exhibited longer survival times, higher tissue perfusion, less intestinal injury, and lower cytokines versus untreated CLP-BK β1-KO mice. These improvements were absent in treated CLP-WT mice, although saline + nicardipine improved blood pressure similarly in both septic mice. At 24 h post-CLP, BK and L-type Ca2+ channel functions in vitro were maintained in mesenteric arteries from WT mice. Mesenteric arteries from BK β1-KO mice had blunted BK/enhanced L-type Ca2+ channel function. We conclude that vascular BK channel deficiency exaggerates mortality in septic BK β1-KO mice by activating L-type Ca2+ channels leading to blood pressure-independent tissue ischemia.
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Lai MH, Wu Y, Gao Z, Anderson ME, Dalziel JE, Meredith AL. BK channels regulate sinoatrial node firing rate and cardiac pacing in vivo. Am J Physiol Heart Circ Physiol 2014; 307:H1327-38. [PMID: 25172903 DOI: 10.1152/ajpheart.00354.2014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Large-conductance Ca(2+)- and voltage-activated K(+) (BK) channels play prominent roles in shaping muscle and neuronal excitability. In the cardiovascular system, BK channels promote vascular relaxation and protect against ischemic injury. Recently, inhibition of BK channels has been shown to lower heart rate in intact rodents and isolated hearts, suggesting a novel role in heart function. However, the underlying mechanism is unclear. In the present study, we recorded ECGs from mice injected with paxilline (PAX), a membrane-permeable BK channel antagonist, and examined changes in cardiac conduction. ECGs revealed a 19 ± 4% PAX-induced reduction in heart rate in wild-type but not BK channel knockout (Kcnma1(-/-)) mice. The heart rate decrease was associated with slowed cardiac pacing due to elongation of the sinus interval. Action potential firing recorded from isolated sinoatrial node cells (SANCs) was reduced by 55 ± 15% and 28 ± 9% by application of PAX (3 μM) and iberiotoxin (230 nM), respectively. Furthermore, baseline firing rates from Kcnma1(-/-) SANCs were 33% lower than wild-type SANCs. The slowed firing upon BK current inhibition or genetic deletion was due to lengthening of the diastolic depolarization phase of the SANC action potential. Finally, BK channel immunoreactivity and PAX-sensitive currents were identified in SANCs with HCN4 expression and pacemaker current, respectively, and BK channels cloned from SANCs recapitulated similar activation as the PAX-sensitive current. Together, these data localize BK channels to SANCs and demonstrate that loss of BK current decreases SANC automaticity, consistent with slowed sinus pacing after PAX injection in vivo. Furthermore, these findings suggest BK channels are potential therapeutic targets for disorders of heart rate.
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Affiliation(s)
- Michael H Lai
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Yuejin Wu
- Department of Internal Medicine and the François M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
| | - Zhan Gao
- Department of Internal Medicine and the François M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
| | - Mark E Anderson
- Department of Internal Medicine and the François M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa; Department of Physiology and Molecular Biophysics, University of Iowa, Iowa City, Iowa; and
| | - Julie E Dalziel
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; Fischell Department of Bioengineering, University of Maryland, College Park, Maryland;
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Lorca RA, Prabagaran M, England SK. Functional insights into modulation of BKCa channel activity to alter myometrial contractility. Front Physiol 2014; 5:289. [PMID: 25132821 PMCID: PMC4116789 DOI: 10.3389/fphys.2014.00289] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 07/14/2014] [Indexed: 12/15/2022] Open
Abstract
The large-conductance voltage- and Ca(2+)-activated K(+) channel (BKCa) is an important regulator of membrane excitability in a wide variety of cells and tissues. In myometrial smooth muscle, activation of BKCa plays essential roles in buffering contractility to maintain uterine quiescence during pregnancy and in the transition to a more contractile state at the onset of labor. Multiple mechanisms of modulation have been described to alter BKCa channel activity, expression, and cellular localization. In the myometrium, BKCa is regulated by alternative splicing, protein targeting to the plasma membrane, compartmentation in membrane microdomains, and posttranslational modifications. In addition, interaction with auxiliary proteins (i.e., β1- and β2-subunits), association with G-protein coupled receptor signaling pathways, such as those activated by adrenergic and oxytocin receptors, and hormonal regulation provide further mechanisms of variable modulation of BKCa channel function in myometrial smooth muscle. Here, we provide an overview of these mechanisms of BKCa channel modulation and provide a context for them in relation to myometrial function.
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Affiliation(s)
- Ramón A Lorca
- Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine St. Louis, MO, USA
| | - Monali Prabagaran
- Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine St. Louis, MO, USA
| | - Sarah K England
- Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine St. Louis, MO, USA
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Yang C, Yang J, Xu X, Yan S, Pan S, Pan X, Zhang C, Leung GP. Vasodilatory effect of 14,15-epoxyeicosatrienoic acid on mesenteric arteries in hypertensive and aged rats. Prostaglandins Other Lipid Mediat 2014; 112:1-8. [PMID: 24880050 DOI: 10.1016/j.prostaglandins.2014.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Revised: 05/17/2014] [Accepted: 05/20/2014] [Indexed: 01/22/2023]
Abstract
The objective of this study was to investigate the 14,15-epoxyeicosatrienoic acid (14,15-EET)-induced vasodilatations as well as the underlying signaling pathways in rat mesenteric arteries from young, adult and old normotensive (WKY) and hypertensive rats. Protein expressions for prostaglandin EP(1-4) receptors, large conductance Ca(2+)-activated K(+) (BK(Ca)) channels, and adenylate cyclase (AC) were determined together with 14,15-EET-induced vasodilatations in primary- versus secondary-branches of the mesenteric artery. Responses to 14,15-EET were greater in the smaller secondary- versus primary-branches (and also more sensitive with lower EC50) and were reduced in vessels from old (80 weeks) rats as well as from vessels from the spontaneous hypertensive rats (SHR). Regardless of age or hypertension responses to 14,15-EET were inhibited by the EP2 antagonist AH6809, BK(Ca) channel inhibitor iberiotoxin, or 3',5'-cyclic monophosphate (cAMP)-protein kinase A (PKA) pathway antagonists. These data indicate 14,15-EET-induced vasodilatation is mediated via the activation of EP2 receptors and opening of BK(Ca) channels. The expressions of the EP2 receptor and AC were markedly reduced in vessels from SHR as well as old rats, whereas BK(Ca) expression was reduced in old WKY and SHR, but not adult SHR. Furthermore, expression of the p53 protein, an indicator of cell senescence and apoptosis, was elevated in adult and old SHR as well as in old WKY. In summary, attenuated 14,15-EET-induced vasodilatation in mesenteric arteries from old normotensive WKY as well as adult and old SHR is associated with reduced expression of EP2 receptors and AC.
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Affiliation(s)
- Cui Yang
- Ethnic Drug Screening & Pharmacology Center, Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming 650500, China; Department of Pharmacology & Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Jinyan Yang
- Ethnic Drug Screening & Pharmacology Center, Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming 650500, China
| | - Xiangting Xu
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - Sanmei Yan
- Ethnic Drug Screening & Pharmacology Center, Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming 650500, China
| | - Shitian Pan
- Ethnic Drug Screening & Pharmacology Center, Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming 650500, China
| | - Xiaoxia Pan
- Ethnic Drug Screening & Pharmacology Center, Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming 650500, China
| | - Changhong Zhang
- School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming 650500, China
| | - George Pakheng Leung
- Department of Pharmacology & Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
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Hayoz S, Bradley V, Boerman EM, Nourian Z, Segal SS, Jackson WF. Aging increases capacitance and spontaneous transient outward current amplitude of smooth muscle cells from murine superior epigastric arteries. Am J Physiol Heart Circ Physiol 2014; 306:H1512-24. [PMID: 24705555 DOI: 10.1152/ajpheart.00492.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Large conductance Ca(2+)-activated K(+) channels (BKCa) contribute to negative feedback regulation of smooth muscle cell (SMC) tone. However, the effects of aging on BKCa function are unclear. We tested the hypothesis that aging alters SMC BKCa function in superior epigastric arteries (SEAs) by using perforated patch recording of enzymatically isolated SMCs from 3- to 4-mo-old male C57BL/6 mice (Young) and 24- to 26-mo-old male C57BL/6 mice (Old). SMC capacitance from Young (15.7 ± 0.4 pF; n = 110) was less than Old (17.9 ± 0.5 pF; n = 104) (P < 0.05). SMCs displayed spontaneous transient outward currents (STOCs) at membrane potentials more positive than -30 mV; depolarization increased STOC amplitude and frequency (P < 0.05; n = 19-24). STOC frequency in Young (2.2 ± 0.6 Hz) was less than Old (4.2 ± 0.7 Hz) at -10 mV (P < 0.05, n = 27-30), with no difference in amplitude (1.0 ± 0.1 vs. 0.9 ± 0.1 pA/pF, respectively). At +30 mV, STOC amplitude in Young (3.2 ± 0.3 pA/pF) was less than Old (5.0 ± 0.5 pA/pF; P < 0.05, n = 61-67) with no difference in frequency (3.9 ± 0.4 vs. 3.2 ± 0.3 Hz, respectively). BKCa blockers (1 μM paxilline, 100 nM iberiotoxin, 1 mM tetraethylammonium) or a ryanodine receptor antagonist (100 μM tetracaine) inhibited STOCs (n ≥ 6; P < 0.05 each). Western blots revealed increased expression of BKCa α-subunit protein in Old. Pressure myography revealed no effect of age on SEA maximal diameter, myogenic tone, or paxilline-induced constriction (n = 10-12; P > 0.05). Enhanced functional expression of SMC BKCa-dependent STOCs in Old may represent an adaptation of resistance arteries to maintain functional integrity.
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Affiliation(s)
- Sebastien Hayoz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Vanessa Bradley
- College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and
| | - Zahra Nourian
- Dalton Cardiovascular Research Center, Columbia, Missouri
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and Dalton Cardiovascular Research Center, Columbia, Missouri
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan;
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38
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Cox N, Toro B, Pacheco-Otalora LF, Garrido-Sanabria ER, Zarei MM. An endoplasmic reticulum trafficking signal regulates surface expression of β4 subunit of a voltage- and Ca²⁺-activated K⁺ channel. Brain Res 2014; 1553:12-23. [PMID: 24486049 DOI: 10.1016/j.brainres.2014.01.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 01/16/2014] [Accepted: 01/17/2014] [Indexed: 12/24/2022]
Abstract
Voltage-dependent and calcium-activated K⁺ (MaxiK, BK) channels are widely expressed in many tissues and organs where they play various physiological roles. Here we report discovery of a functional trafficking signal in MaxiK channel accessory β4 subunit that could regulate activity of MaxiK α subunit (hSlo) on the plasma membrane. We demonstrate that β4 is mostly retained within the cell and removal or mutation of β4 trafficking signal significantly enhances its surface expression in HEK293T expression system. In hippocampal slices and cultured neurons we also observed significant β4 expressions within the neurons. Finally, we show that unlike SV1 and β1 subunits, β4 shows no dominant-negative effect on MaxiK channel α subunit. Taken together, we propose β4 subunit of MaxiK channel is mostly retained within the cells without interfering with other subunits. Removal of β4 retention signal increases its surface expression that may lead to reduction of the MaxiK channel activity and neuronal excitability.
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Affiliation(s)
- N Cox
- Center for Biomedical Studies, University of Texas at Brownsville, Brownsville, TX 78520, USA
| | - B Toro
- South Texas Arthritis Center, Brownsville, TX 78526, USA
| | - L F Pacheco-Otalora
- Biomedicine Department, University of Texas at Brownsville, Brownsville, TX 78520, USA
| | - E R Garrido-Sanabria
- Center for Biomedical Studies, University of Texas at Brownsville, Brownsville, TX 78520, USA; Biomedicine Department, University of Texas at Brownsville, Brownsville, TX 78520, USA
| | - M M Zarei
- Center for Biomedical Studies, University of Texas at Brownsville, Brownsville, TX 78520, USA; Biomedicine Department, University of Texas at Brownsville, Brownsville, TX 78520, USA.
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39
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Martín P, Moncada M, Enrique N, Asuaje A, Valdez Capuccino JM, Gonzalez C, Milesi V. Arachidonic acid activation of BKCa (Slo1) channels associated to the β1-subunit in human vascular smooth muscle cells. Pflugers Arch 2013; 466:1779-92. [DOI: 10.1007/s00424-013-1422-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 12/03/2013] [Accepted: 12/05/2013] [Indexed: 01/10/2023]
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40
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Shi L, Liu B, Zhang Y, Xue Z, Liu Y, Chen Y. Exercise Training Reverses Unparallel Downregulation of MaxiK Channel - and 1-Subunit to Enhance Vascular Function in Aging Mesenteric Arteries. J Gerontol A Biol Sci Med Sci 2013; 69:1462-73. [DOI: 10.1093/gerona/glt205] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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41
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Shi L, Liu X, Li N, Liu B, Liu Y. Aging decreases the contribution of MaxiK channel in regulating vascular tone in mesenteric artery by unparallel downregulation of α- and β1-subunit expression. Mech Ageing Dev 2013; 134:416-25. [DOI: 10.1016/j.mad.2013.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/22/2013] [Accepted: 09/03/2013] [Indexed: 02/02/2023]
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42
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Chronobiology of Micturition: Putative Role of the Circadian Clock. J Urol 2013; 190:843-9. [DOI: 10.1016/j.juro.2013.02.024] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2013] [Indexed: 12/13/2022]
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43
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Hu Z, Ma A, Tian H, Xi Y, Fan L, Wang T. Effects of age on expression of BKca channel in vascular smooth muscle cells from mesenteric arteries of spontaneously hypertensive rats. J Physiol Biochem 2013; 69:945-55. [DOI: 10.1007/s13105-013-0273-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 07/02/2013] [Indexed: 10/26/2022]
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44
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Price JM, Hellermann A, Hellermann G, Sutton ET. Aging enhances vascular dysfunction induced by the Alzheimer's peptide β-amyloid. Neurol Res 2013; 26:305-11. [PMID: 15142324 DOI: 10.1179/016164104225014003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Aging is a major risk factor for Alzheimer's disease and the evidence suggests a role for cerebrovascular pathology in cognitive dysfunction. The hypothesis in this study is that aging is a significant risk factor in the effect of the Alzheimer peptide beta-amyloid on endothelium-dependent function of cerebral and peripheral vessels. The diameter response to acetylcholine, an endothelium-dependent vasodilator, was recorded in pressurized segments of rat posterior cerebral vessels from mature (3 months) and aged (20 months) rats. The threshold concentration of beta-amyloid for a significant decrease in the response to acetylcholine was lower in vessels from aged rats (10(-9) M) than in vessels from mature rats (10(-8) M). The threshold concentration of beta-amyloid for a significant decrease in the sensitivity to acetylcholine was lower for ring segments of aorta from aged rats (10(-10) M) than for aorta from mature rats (10(-8) M). Structural changes of the endothelium were first observed in electron micrographs of aorta from aged rats when the concentration of beta-amyloid was 10(-8) M, whereas structural changes in aorta from mature rats did not occur until the concentration of beta-amyloid was increased to 10(-7) M. The results suggest that aging increases the susceptibility of cerebral and peripheral blood vessels to beta-amyloid related dysfunction and that functional change precedes structural change.
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Affiliation(s)
- Joel M Price
- Department of Physiology and Biophysics, University of South Florida, College of Medicine, Tampa, Florida 33612, USA.
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45
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Vasodilator compounds derived from plants and their mechanisms of action. Molecules 2013; 18:5814-57. [PMID: 23685938 PMCID: PMC6270466 DOI: 10.3390/molecules18055814] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 04/24/2013] [Accepted: 05/07/2013] [Indexed: 12/31/2022] Open
Abstract
The present paper reviews vasodilator compounds isolated from plants that were reported in the past 22 years (1990 to 2012) and the different mechanisms of action involved in their vasodilator effects. The search for reports was conducted in a comprehensive manner, intending to encompass those metabolites with a vasodilator effect whose mechanism of action involved both vascular endothelium and arterial smooth muscle. The results obtained from our bibliographic search showed that over half of the isolated compounds have a mechanism of action involving the endothelium. Most of these bioactive metabolites cause vasodilation either by activating the nitric oxide/cGMP pathway or by blocking voltage-dependent calcium channels. Moreover, it was found that many compounds induced vasodilation by more than one mechanism. This review confirms that secondary metabolites, which include a significant group of compounds with extensive chemical diversity, are a valuable source of new pharmaceuticals useful for the treatment and prevention of cardiovascular diseases.
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46
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Abstract
Despite recent advances in our understanding of the molecular and cellular mechanisms behind vascular conducted responses (VCRs) in systemic arterioles, we still know very little about their potential physiological and pathophysiological role in brain penetrating arterioles controlling blood flow to the deeper areas of the brain. The scope of the present review is to present an overview of the conceptual, mechanistic, and physiological role of VCRs in resistance vessels, and to discuss in detail the recent advances in our knowledge of VCRs in brain arterioles controlling cerebral blood flow. We provide a schematic view of the ion channels and intercellular communication pathways necessary for conduction of an electrical and mechanical response in the arteriolar wall, and discuss the local signaling mechanisms and cellular pathway involved in the responses to different local stimuli and in different vascular beds. Physiological modulation of VCRs, which is a rather new finding in this field, is discussed in the light of changes in plasma membrane ion channel conductance as a function of health status or disease. Finally, we discuss the possible role of VCRs in cerebrovascular function and disease as well as suggest future directions for studying VCRs in the cerebral circulation.
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47
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Effect of aging on calcium signaling in C57Bl6J mouse cerebral arteries. Pflugers Arch 2012; 465:829-38. [DOI: 10.1007/s00424-012-1195-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 01/08/2023]
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48
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Hu XQ, Zhang L. Function and regulation of large conductance Ca(2+)-activated K+ channel in vascular smooth muscle cells. Drug Discov Today 2012; 17:974-87. [PMID: 22521666 PMCID: PMC3414640 DOI: 10.1016/j.drudis.2012.04.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/06/2012] [Accepted: 04/05/2012] [Indexed: 12/23/2022]
Abstract
Large conductance Ca(2+)-activated K(+) (BK(Ca)) channels are abundantly expressed in vascular smooth muscle cells. Activation of BK(Ca) channels leads to hyperpolarization of cell membrane, which in turn counteracts vasoconstriction. Therefore, BK(Ca) channels have an important role in regulation of vascular tone and blood pressure. The activity of BK(Ca) channels is subject to modulation by various factors. Furthermore, the function of BK(Ca) channels are altered in both physiological and pathophysiological conditions, such as pregnancy, hypertension and diabetes, which has dramatic impacts on vascular tone and hemodynamics. Consequently, compounds and genetic manipulation that alter activity and expression of the channel might be of therapeutic interest.
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Affiliation(s)
- Xiang-Qun Hu
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
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49
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Abstract
We determined the contribution of vascular BK channels to endotoxin (lipopolysaccharide, LPS)-induced hypotension, organ damage, and mortality using smooth muscle BK channel deficiency (BK channel β1-subunit knockout, BK β1-KO) mice. BK β1-KO mice were more sensitive to LPS-induced mortality compared with wild-type mice. After LPS (20 mg/kg, intraperitoneally), BK β1-KO mice had a more rapid fall in heart rate and blood pressure (measured by radiotelemetry), shorter latency to mortality, and higher mortality rate than wild-type mice. Twenty-two hours after LPS treatment, wild-type and BK β1-KO mice had reduced norepinephrine reactivity and impaired constrictor responses to the BK channel blocker paxilline in mesenteric arteries in vitro and higher iNOS expression in the heart, but not in mesenteric arteries. Endotoxemic BK β1-KO mice also showed more severe lung and intestinal injury, higher myeloperoxidase activity and polymorphonuclear neutrophil infiltration in lung and liver. Endotoxemic BK β1-KO mice had higher plasma tumor necrosis factor α and interleukin 6 levels at 22 hours, but not 6 hours post-LPS. Exaggerated mortality in BK β1-KO mice also occurred in the cecal ligation/puncture model of septic shock. Reduced vascular BK channel function does not protect against hypotension in the early stage of septic shock; in the later stage, smooth muscle BK channel deficiency enhances organ damage and mortality.
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50
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Lopes RAM, Neves KB, Carneiro FS, Tostes RC. Testosterone and vascular function in aging. Front Physiol 2012; 3:89. [PMID: 22514541 PMCID: PMC3322529 DOI: 10.3389/fphys.2012.00089] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 03/25/2012] [Indexed: 11/13/2022] Open
Abstract
Androgen receptors are widely distributed in several tissues, including vascular endothelial and smooth muscle cells. Through classic cytosolic androgen receptors or membrane receptors, testosterone induces genomic and non-genomic effects, respectively. Testosterone interferes with the vascular function by increasing the production of pro-inflammatory cytokines and arterial thickness. Experimental evidence indicates that sex steroid hormones, such as testosterone modulate the synthesis and bioavailability of NO and, consequently, endothelial function, which is key for a healthy vasculature. Of interest, aging itself is accompanied by endothelial and vascular smooth muscle dysfunction. Aging-associated decline of testosterone levels is accompanied by age-related diseases, such as metabolic and cardiovascular diseases, indicating that very low levels of androgens may contribute to cardiovascular dysfunction observed in these age-related disorders or, in other words, that testosterone may have beneficial effects in the cardiovascular system. However, testosterone seems to play a negative role in the severity of renal disease. In this mini-review, we briefly comment on the interplay between aging and testosterone levels, the vascular actions of testosterone and its implications for vascular aging. Renal effects of testosterone and the use of testosterone to prevent vascular dysfunction in elderly are also addressed.
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Affiliation(s)
- Rhéure A M Lopes
- Department of Pharmacology, Medical School of Ribeirao Preto, Ribeirao Preto São Paulo, Brazil
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