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Lin J, Guo W, Luo Q, Zhang Q, Wan T, Jiang C, Ye Y, Lin H, Fan G. Senolytics prevent caveolar Ca V 3.2-RyR axis malfunction in old vascular smooth muscle. Aging Cell 2023; 22:e14002. [PMID: 37837625 PMCID: PMC10652315 DOI: 10.1111/acel.14002] [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: 02/05/2023] [Revised: 07/18/2023] [Accepted: 08/07/2023] [Indexed: 10/16/2023] Open
Abstract
Aging is a major risk factor for cardiovascular diseases. Our previous studies demonstrate that aging impairs the caveolar T-type CaV 3.2-RyR axis for extracellular Ca2+ influx to trigger Ca2+ sparks in vascular smooth muscle cells (VSMCs). We hypothesize that the administration of senolytics, which can selectively clear senescent cells, could preserve the caveolar CaV 3.2-RyR axis in aging VSMCs. In this study, 10-month-old mice were administered the senolytics cocktail consisting of dasatinib (5 mg/kg) and quercetin (50 mg/kg) or vehicle bi-weekly for 4 months. Using VSMCs from mouse mesenteric arteries, we found that Ca2+ sparks were diminished after caveolae disruption by methyl-β-cyclodextrin (10 mM) in cells from D + Q treated but not vehicle-treated 14-month-old mice. D + Q treatment promoted the expression of CaV 3.2 in 14-month-old mesenteric arteries. Structural analysis using electron tomography and immunofluorescence staining revealed the remodeling of caveolae and co-localization of CaV 3.2-Cav-1 in D + Q treatment aged mesenteric arteries. In keeping with theoretical observations, Cav 3.2 channel inhibition by Ni2+ (50 μM) suppressed Ca2+ in VSMCs from the D + Q group, with no effect observed in vehicle-treated arteries. Our study provides evidence that age-related caveolar CaV 3.2-RyR axis malfunction can be alleviated by pharmaceutical intervention targeting cellular senescence. Our findings support the potential of senolytics for ameliorating age-associated cardiovascular disease.
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Affiliation(s)
- Jie Lin
- Cardiology DepartmentThe first Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Weiming Guo
- Sports Medicine CenterHuazhong University of Science and Technology Union Shenzhen Hospital, the 6th affiliated Hospital of Shenzhen University Medical SchoolShenzhenChina
| | - Qingtian Luo
- Department of GastroenterologyHuazhong University of Science and Technology Union Shenzhen Hospital, the 6th affiliated Hospital of Shenzhen University Medical SchoolShenzhenChina
| | - Qingping Zhang
- Neurology DepartmentHuazhong University of Science and Technology Union Shenzhen Hospital, the 6th affiliated Hospital of Shenzhen University Medical SchoolShenzhenChina
| | - Teng Wan
- Sports Medicine CenterHuazhong University of Science and Technology Union Shenzhen Hospital, the 6th affiliated Hospital of Shenzhen University Medical SchoolShenzhenChina
| | - Changyu Jiang
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain MedicineHuazhong University of Science and Technology Union Shenzhen Hospital, the 6th affiliated Hospital of Shenzhen University Medical SchoolShenzhenChina
| | - Yuanchun Ye
- Quanzhou First Hospital Affiliated to Fujian Medical UniversityQuanzhouFujian ProvinceChina
| | - Haihuan Lin
- Cardiology DepartmentThe first Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Gang Fan
- Urology department, Huazhong University of Science and Technology Union Shenzhen Hospitalthe 6th affiliated Hospital of Shenzhen University Medical SchoolShenzhenChina
- Hunan Cancer Hospital, the Affiliated Cancer Hospital of Xiangya School of MedicineCentral South UniversityChangshaChina
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Howlett LA, Stevenson-Cocks H, Colman MA, Lancaster MK, Benson AP. Ionic current changes underlying action potential repolarization responses to physiological pacing and adrenergic stimulation in adult rat ventricular myocytes. Physiol Rep 2023; 11:e15766. [PMID: 37495507 PMCID: PMC10371833 DOI: 10.14814/phy2.15766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/28/2023] Open
Abstract
This study aimed to simulate ventricular responses to elevations in myocyte pacing and adrenergic stimulation using a novel electrophysiological rat model and investigate ion channel responses underlying action potential (AP) modulations. Peak ion currents and AP repolarization to 50% and 90% of full repolarization (APD50-90 ) were recorded during simulations at 1-10 Hz pacing under control and adrenergic stimulation conditions. Further simulations were performed with incremental ion current block (L-type calcium current, ICa ; transient outward current, Ito ; slow delayed rectifier potassium current, IKs ; rapid delayed rectifier potassium current, IKr ; inward rectifier potassium current, IK1 ) to identify current influence on AP response to exercise. Simulated APD50-90 closely resembled experimental findings. Rate-dependent increases in IKs (6%-101%), IKr (141%-1339%), and ICa (0%-15%) and reductions in Ito (11%-57%) and IK1 (1%-9%) were observed. Meanwhile, adrenergic stimulation triggered moderate increases in all currents (23%-67%) except IK1 . Further analyses suggest AP plateau is most sensitive to modulations in Ito and ICa while late repolarization is most sensitive to IK1 , ICa , and IKs , with alterations in IKs predominantly stimulating the greatest magnitude of influence on late repolarization (35%-846% APD90 prolongation). The modified Leeds rat model (mLR) is capable of accurately modeling APs during physiological stress. This study highlights the importance of ICa , Ito , IK1, and IKs in controlling electrophysiological responses to exercise. This work will benefit the study of cardiac dysfunction, arrythmia, and disease, though future physiologically relevant experimental studies and model development are required.
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Affiliation(s)
- Luke A Howlett
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | | | | | | | - Alan P Benson
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
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3
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The Aging Heart: A Molecular and Clinical Challenge. Int J Mol Sci 2022; 23:ijms232416033. [PMID: 36555671 PMCID: PMC9783309 DOI: 10.3390/ijms232416033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/05/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Aging is associated with an increasing burden of morbidity, especially for cardiovascular diseases (CVDs). General cardiovascular risk factors, ischemic heart diseases, heart failure, arrhythmias, and cardiomyopathies present a significant prevalence in older people, and are characterized by peculiar clinical manifestations that have distinct features compared with the same conditions in a younger population. Remarkably, the aging heart phenotype in both healthy individuals and patients with CVD reflects modifications at the cellular level. An improvement in the knowledge of the physiological and pathological molecular mechanisms underlying cardiac aging could improve clinical management of older patients and offer new therapeutic targets.
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Dixon RE. Nanoscale Organization, Regulation, and Dynamic Reorganization of Cardiac Calcium Channels. Front Physiol 2022; 12:810408. [PMID: 35069264 PMCID: PMC8769284 DOI: 10.3389/fphys.2021.810408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 11/30/2021] [Indexed: 12/19/2022] Open
Abstract
The architectural specializations and targeted delivery pathways of cardiomyocytes ensure that L-type Ca2+ channels (CaV1.2) are concentrated on the t-tubule sarcolemma within nanometers of their intracellular partners the type 2 ryanodine receptors (RyR2) which cluster on the junctional sarcoplasmic reticulum (jSR). The organization and distribution of these two groups of cardiac calcium channel clusters critically underlies the uniform contraction of the myocardium. Ca2+ signaling between these two sets of adjacent clusters produces Ca2+ sparks that in health, cannot escalate into Ca2+ waves because there is sufficient separation of adjacent clusters so that the release of Ca2+ from one RyR2 cluster or supercluster, cannot activate and sustain the release of Ca2+ from neighboring clusters. Instead, thousands of these Ca2+ release units (CRUs) generate near simultaneous Ca2+ sparks across every cardiomyocyte during the action potential when calcium induced calcium release from RyR2 is stimulated by depolarization induced Ca2+ influx through voltage dependent CaV1.2 channel clusters. These sparks summate to generate a global Ca2+ transient that activates the myofilaments and thus the electrical signal of the action potential is transduced into a functional output, myocardial contraction. To generate more, or less contractile force to match the hemodynamic and metabolic demands of the body, the heart responds to β-adrenergic signaling by altering activity of calcium channels to tune excitation-contraction coupling accordingly. Recent accumulating evidence suggests that this tuning process also involves altered expression, and dynamic reorganization of CaV1.2 and RyR2 channels on their respective membranes to control the amplitude of Ca2+ entry, SR Ca2+ release and myocardial function. In heart failure and aging, altered distribution and reorganization of these key Ca2+ signaling proteins occurs alongside architectural remodeling and is thought to contribute to impaired contractile function. In the present review we discuss these latest developments, their implications, and future questions to be addressed.
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Affiliation(s)
- Rose E Dixon
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, CA, United States
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5
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Howlett LA, Lancaster MK. Reduced cardiac response to the adrenergic system is a key limiting factor for physical capacity in old age. Exp Gerontol 2021; 150:111339. [PMID: 33838216 DOI: 10.1016/j.exger.2021.111339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/02/2021] [Accepted: 04/03/2021] [Indexed: 10/21/2022]
Abstract
Ageing is associated with a progressive reduction in physical capacity reducing quality of life. One key physiological limitation of physical capacity that deteriorates in a progressive age-dependent manner is cardiac reserve. Peak cardiac output falls progressively with advancing age such that in extreme old age there is limited ability to enhance cardiac output beyond basal function as is required to support the increased metabolic needs of physical activity. This loss of dynamic range in cardiac output associates with a progressive reduction in the heart's response to adrenergic stimulation. A combination of decreases in the expression and functioning of beta1 adrenergic receptors partially underlies this change. Changes in end effector proteins also have a role to play in this decline. Alterations in the efficiency of excitation-contraction coupling contribute to the reduced chronotropic, inotropic and lusitropic responses of the aged heart. Moderate to vigorous endurance exercise training however has some potential to counter elements of these changes. Further studies are required to fully elucidate the key pivotal mechanisms involved in the age-related loss of response to adrenergic signalling to allow targeted therapeutic strategies to be developed with the aim of preserving physical capacity in advanced old age.
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Affiliation(s)
- Luke A Howlett
- Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.
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Segovia-Roldan M, Diez ER, Pueyo E. Melatonin to Rescue the Aged Heart: Antiarrhythmic and Antioxidant Benefits. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8876792. [PMID: 33791076 PMCID: PMC7984894 DOI: 10.1155/2021/8876792] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/16/2021] [Accepted: 01/23/2021] [Indexed: 12/19/2022]
Abstract
Aging comes with gradual loss of functions that increase the vulnerability to disease, senescence, and death. The mechanisms underlying these processes are linked to a prolonged imbalance between damage and repair. Damaging mechanisms include oxidative stress, mitochondrial dysfunction, chronodisruption, inflammation, and telomere attrition, as well as genetic and epigenetic alterations. Several endogenous tissue repairing mechanisms also decrease. These alterations associated with aging affect the entire organism. The most devastating manifestations involve the cardiovascular system and may lead to lethal cardiac arrhythmias. Together with structural remodeling, electrophysiological and intercellular communication alterations during aging predispose to arrhythmic events. Despite the knowledge on repairing mechanisms in the cardiovascular system, effective antiaging strategies able to reduce the risk of arrhythmias are still missing. Melatonin is a promising therapeutic candidate due to its pleiotropic actions. This indoleamine regulates chronobiology and endocrine physiology. Of relevance, melatonin is an antiaging, antioxidant, antiapoptotic, antiarrhythmic, immunomodulatory, and antiproliferative molecule. This review focuses on the protective effects of melatonin on age-induced cardiac functional and structural alterations, potentially becoming a new fountain of youth for the heart.
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Affiliation(s)
- Margarita Segovia-Roldan
- Biomedical Signal Interpretation and Computational Simulation (BSICoS), I3A, Universidad de Zaragoza, IIS Aragón and CIBER-BBN, Spain
| | | | - Esther Pueyo
- Biomedical Signal Interpretation and Computational Simulation (BSICoS), I3A, Universidad de Zaragoza, IIS Aragón and CIBER-BBN, Spain
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7
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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8
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Rubi L, Todt H, Kubista H, Koenig X, Hilber K. Calcium current properties in dystrophin-deficient ventricular cardiomyocytes from aged mdx mice. Physiol Rep 2018; 6. [PMID: 29333726 PMCID: PMC5789658 DOI: 10.14814/phy2.13567] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 12/11/2017] [Indexed: 11/24/2022] Open
Abstract
Duchenne muscular dystrophy (DMD), caused by mutations in the gene encoding for the cytoskeletal protein dystrophin, is linked with severe cardiac complications including cardiomyopathy development and cardiac arrhythmias. We and others recently reported that currents through L‐type calcium (Ca) channels were significantly increased, and channel inactivation was reduced in dystrophin‐deficient ventricular cardiomyocytes derived from the mdx mouse, the most commonly used animal model for human DMD. These gain‐of‐function Ca channel abnormalities may enhance the risk of Ca‐dependent arrhythmias and cellular Ca overload in the dystrophic heart. All studies, which have so far investigated L‐type Ca channel properties in dystrophic cardiomyocytes, have used hearts from either neonatal or young adult mdx mice as cell source. In consequence, the dimension of the Ca channel abnormalities present in the severely‐diseased aged dystrophic heart has remained unknown. Here, we have studied potential abnormalities in Ca currents and intracellular Ca transients in ventricular cardiomyocytes derived from aged dystrophic mdx mice. We found that both the L‐type and T‐type Ca current properties of mdx cardiomyocytes were similar to those of myocytes derived from aged wild‐type mice. Accordingly, Ca release from the sarcoplasmic reticulum was normal in cardiomyocytes from aged mdx mice. This suggests that, irrespective of the presence of a pronounced cardiomyopathy in aged mdx mice, Ca currents and Ca release in dystrophic cardiomyocytes are normal. Finally, our data imply that dystrophin‐ regulation of L‐type Ca channel function in the heart is lost during aging.
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Affiliation(s)
- Lena Rubi
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Hannes Todt
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Helmut Kubista
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Xaver Koenig
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Karlheinz Hilber
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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9
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Voltage-Dependent Sarcolemmal Ion Channel Abnormalities in the Dystrophin-Deficient Heart. Int J Mol Sci 2018; 19:ijms19113296. [PMID: 30360568 PMCID: PMC6274787 DOI: 10.3390/ijms19113296] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/28/2022] Open
Abstract
Mutations in the gene encoding for the intracellular protein dystrophin cause severe forms of muscular dystrophy. These so-called dystrophinopathies are characterized by skeletal muscle weakness and degeneration. Dystrophin deficiency also gives rise to considerable complications in the heart, including cardiomyopathy development and arrhythmias. The current understanding of the pathomechanisms in the dystrophic heart is limited, but there is growing evidence that dysfunctional voltage-dependent ion channels in dystrophin-deficient cardiomyocytes play a significant role. Herein, we summarize the current knowledge about abnormalities in voltage-dependent sarcolemmal ion channel properties in the dystrophic heart, and discuss the potentially underlying mechanisms, as well as their pathophysiological relevance.
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Karagueuzian HS, Pezhouman A, Angelini M, Olcese R. Enhanced Late Na and Ca Currents as Effective Antiarrhythmic Drug Targets. Front Pharmacol 2017; 8:36. [PMID: 28220073 PMCID: PMC5292429 DOI: 10.3389/fphar.2017.00036] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/18/2017] [Indexed: 11/30/2022] Open
Abstract
While recent advances clarified the molecular and cellular modes of action of antiarrhythmic drugs (AADs), their link to suppression of dynamical arrhythmia mechanisms remains only partially understood. The current classifications of AADs (Classes I, III, and IV) rely on blocking peak Na, K and L-type calcium currents (ICa,L), with Class II with dominant beta receptor blocking activity and Class V including drugs with diverse classes of actions. The discovery that the calcium and redox sensor, cardiac Ca/calmodulin-dependent protein kinase II (CaMKII) enhances both the late Na (INa-L) and the late ICa,L in patients at high risk of VT/VF provided a new and a rational AAD target. Pathological rise of either or both of INa-L and late ICa,L are demonstrated to promote cellular early afterdepolarizations (EADs) and EAD-mediated triggered activity that can initiate VT/VF in remodeled hearts. Selective inhibition of the INa-L without affecting their peak transients with the highly specific prototype drug, GS-967 suppresses these EAD-mediated VT/VFs. As in the case of INa-L, selective inhibition of the late ICa,L without affecting its peak with the prototype drug, roscovitine suppressed oxidative EAD-mediated VT/VF. These findings indicate that specific blockers of the late inward currents without affecting their peaks (gating modifiers), offer a new and effective AAD class action i.e., “Class VI.” The development of safe drugs with selective Class VI actions provides a rational and effective approach to treat VT/VF particularly in cardiac conditions associated with enhanced CaMKII activity such as heart failure.
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Affiliation(s)
- Hrayr S Karagueuzian
- Translational Arrhythmia Section, David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA; Cardiovascular Research Laboratory, Departments of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA
| | - Arash Pezhouman
- Translational Arrhythmia Section, David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA; Cardiovascular Research Laboratory, Departments of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA
| | - Marina Angelini
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA
| | - Riccardo Olcese
- Cardiovascular Research Laboratory, Departments of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA; Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA; Department of Physiology, David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA
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11
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Mirza M, Strunets A, Shen WK, Jahangir A. Mechanisms of arrhythmias and conduction disorders in older adults. Clin Geriatr Med 2013; 28:555-73. [PMID: 23101571 DOI: 10.1016/j.cger.2012.08.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Aging is associated with an increased prevalence of cardiac arrhythmias, which contribute to higher morbidity and mortality in the elderly. The frequency of cardiac arrhythmias, particularly atrial fibrillation and ventricular tachyarrhythmia, is projected to increase as the population ages, greatly impacting health care resource utilization. Several clinical factors associated with the risk of arrhythmias have been identified in the population, yet the molecular bases for the increased predisposition to arrhythmogenesis in the elderly are not fully understood. This review highlights the epidemiology of cardiac dysrhythmias, changes in cardiac structure and function associated with aging, and the basis for arrhythmogenesis in the elderly.
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Affiliation(s)
- Mahek Mirza
- Center for Integrative Research on Cardiovascular Aging (CIRCA), Aurora University of Wisconsin Medical Group, Aurora Health Care, 3033 South 27th Street, Milwaukee, WI 53215, USA
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12
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Corcoran TB, Hillyard S. Cardiopulmonary aspects of anaesthesia for the elderly. Best Pract Res Clin Anaesthesiol 2011; 25:329-54. [DOI: 10.1016/j.bpa.2011.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 07/12/2011] [Indexed: 02/03/2023]
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13
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Ly HQ, Kawase Y, Hajjar RJ. Advances in gene-based therapy for heart failure. J Cardiovasc Transl Res 2008; 1:127-36. [PMID: 20559907 DOI: 10.1007/s12265-008-9022-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 03/17/2008] [Indexed: 01/08/2023]
Abstract
Heart failure is a major cause of morbidity and mortality in western countries. While progress in current treatment modalities is making steady and incremental gains to reduce this disease burden, there remains a need to explore novel therapeutic strategies. Clinicians and researchers alike have thus looked towards novel adjunctive therapeutic strategies, including gene-based therapy for congestive heart failure (CHF). Advances in the understanding of the molecular basis of CHF, combined to the evolution of increasingly efficient gene transfer technology, have placed congestive heart failure within reach of gene-based therapy. This review will discuss issues related to gene vector systems, gene delivery strategies, and gene targets for intervention in the setting of CHF.
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Affiliation(s)
- Hung Q Ly
- Cardiovascular Research Center, Mount Sinai School of Medicine, One Gustave L. Levy Place, P.O. Box 1030, New York, NY 10029, USA
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14
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Chen X, Zhang X, Harris DM, Piacentino V, Berretta RM, Margulies KB, Houser SR. Reduced effects of BAY K 8644 on L-type Ca2+ current in failing human cardiac myocytes are related to abnormal adrenergic regulation. Am J Physiol Heart Circ Physiol 2008; 294:H2257-67. [PMID: 18359894 DOI: 10.1152/ajpheart.01335.2007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abnormal L-type Ca(2+) channel (LTCC, also named Cav1.2) density and regulation are important contributors to depressed contractility in failing hearts. The LTCC agonist BAY K 8644 (BAY K) has reduced inotropic effects on failing myocardium. We hypothesized that BAY K effects on the LTCC current (I(CaL)) in failing myocytes would be reduced because of increased basal activity. Since support of the failing heart with a left ventricular assist device (LVAD) improves contractility and adrenergic responses, we further hypothesized that BAY K effects on I(CaL) would be restored in LVAD-supported failing hearts. We tested our hypotheses in human ventricular myocytes (HVMs) isolated from nonfailing (NF), failing (F), and LVAD-supported failing hearts. We found that 1) BAY K had smaller effects on I(CaL) in F HVMs compared with NF HVMs; 2) BAY K had diminished effects on I(CaL) in NF HVM pretreated with isoproterenol (Iso) or dibutyryl cyclic AMP (DBcAMP); 3) BAY K effects on I(CaL) in F HVMs pretreated with acetylcholine (ACh) were normalized; 4) Iso had no effect on NF HVMs pretreated with BAY K; 5) BAY K effects on I(CaL) in LVAD HVMs were similar to those in NF HVMs; 6) BAY K effects were reduced in LVAD HVMs pretreated with Iso or DBcAMP; 7) Iso had no effect on I(CaL) in LVAD HVMs pretreated with BAY K. Collectively, these results suggest that the decreased BAY K effects on LTCC in F HVMs are caused by increased basal channel activity, which should contribute to abnormal contractility reserve.
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Affiliation(s)
- Xiongwen Chen
- Cardiovascular Research Center and Department of Physiology, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, PA 19140, USA
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15
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Abstract
Heart failure is a major cause of morbidity and mortality in contemporary societies. Although progress in conventional treatment modalities is making steady and incremental gains to reduce this disease burden, there remains a need to explore new and potentially therapeutic approaches. Gene therapy, for example, was initially envisioned as a treatment strategy for inherited monogenic disorders. It is now apparent that gene therapy has broader potential that also includes acquired polygenic diseases, such as heart failure. Advances in the understanding of the molecular basis of conditions such as these, together with the evolution of increasingly efficient gene transfer technology, has placed congestive heart failure within reach of gene-based therapy.
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Affiliation(s)
- Hung Ly
- Cardiology Division, Cardiovascular Research Center, the Cardiology Laboratory of Integrative Physiology, Imaging at Massachusetts General Hospital, Boston, MA, USA
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16
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Piccirillo G, Magnanti M, Matera S, Di Carlo S, De Laurentis T, Torrini A, Marchitto N, Ricci R, Magrí D. Age and QT variability index during free breathing, controlled breathing and tilt in patients with chronic heart failure and healthy control subjects. Transl Res 2006; 148:72-8. [PMID: 16890147 DOI: 10.1016/j.trsl.2006.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 01/05/2006] [Accepted: 02/22/2006] [Indexed: 11/25/2022]
Abstract
UNLABELLED The QT variability index (QTVI) indicates temporal dispersion in myocardial repolarization, and a high QTVI is associated with a propensity for sudden death from malignant ventricular arrhythmias in subjects at high risk. In this study, the authors assessed the effects of free breathing, controlled breathing, and sympathetic stress (tilt) on the QTVI in patients with chronic heart failure (CHF) and healthy control subjects. The authors also examined the influence of age on the same variables. To obtain normative data, they calculated 95% confidence intervals for healthy subjects grouped according to age. Under all experimental conditions, the QTVI was larger in the CHF group overall and in the age subsets than in controls. In patients and controls, the QTVI increased significantly during tilt, although no differences were found between the QTVI measured during free and controlled breathing. In healthy controls, the following variables correlated significantly with the QTVI: age and baseline heart rate (P < 0.001). In patients with CHF, aging had no influence on the QTVI. CONCLUSION Age, sympathetic stress, and CHF all tend to increase the QTVI and could potentially induce sudden death. Further studies should assess the usefulness of the QTVI as a marker predicting sudden cardiac death under the various conditions of risk.
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Affiliation(s)
- Gianfranco Piccirillo
- Dipartimento di Scienze dell'Invecchiamento, Policlinico Umberto I, Universitá La Sapienza, Rome, Italy.
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17
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Li SY, Du M, Dolence EK, Fang CX, Mayer GE, Ceylan-Isik AF, LaCour KH, Yang X, Wilbert CJ, Sreejayan N, Ren J. Aging induces cardiac diastolic dysfunction, oxidative stress, accumulation of advanced glycation endproducts and protein modification. Aging Cell 2005; 4:57-64. [PMID: 15771609 DOI: 10.1111/j.1474-9728.2005.00146.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Evidence suggests that aging, per se, is a major risk factor for cardiac dysfunction. Oxidative modification of cardiac proteins by non-enzymatic glycation, i.e. advanced glycation endproducts (AGEs), has been implicated as a causal factor in the aging process. This study was designed to examine the role of aging on cardiomyocyte contractile function, cardiac protein oxidation and oxidative modification. Mechanical properties were evaluated in ventricular myocytes from young (2-month) and aged (24-26-month) mice using a MyoCam system. The mechanical indices evaluated were peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90) and maximal velocity of shortening/relengthening (+/- dL/dt). Oxidative stress and protein damage were evaluated by glutathione and glutathione disulfide (GSH/GSSG) ratio and protein carbonyl content, respectively. Activation of NAD(P)H oxidase was determined by immunoblotting. Aged myocytes displayed a larger cell cross-sectional area, prolonged TR90, and normal PS, +/- dL/dt and TPS compared with young myocytes. Aged myocytes were less tolerant of high stimulus frequency (from 0.1 to 5 Hz) compared with young myocytes. Oxidative stress and protein oxidative damage were both elevated in the aging group associated with significantly enhanced p47phox but not gp91phox expression. In addition, level of cardiac AGEs was approximately 2.5-fold higher in aged hearts than young ones determined by AGEs-ELISA. A group of proteins with a molecular range between 50 and 75 kDa with pI of 4-7 was distinctively modified in aged heart using one- or two-dimension SDS gel electrophoresis analysis. These data demonstrate cardiac diastolic dysfunction and reduced stress tolerance in aged cardiac myocytes, which may be associated with enhanced cardiac oxidative damage, level of AGEs and protein modification by AGEs.
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Affiliation(s)
- Shi-Yan Li
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071-3375, USA
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18
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Abstract
Heart failure remains a leading cause of hospital admissions and mortality in the elderly, and current interventional approaches often fail to treat the underlying cause of pathogenesis. Preservation of structure and function in the aging myocardium is most likely to be successful via ongoing cellular repair and replacement, as well as survival of existing cardiomyocytes that generate contractile force. Research has led to a paradigm shift driven by application of stem cells to generate cardiovascular cell lineages. Early controversial findings of pluripotent precursors adopting cardiac phenotypes are now widely accepted, and current debate centers upon the efficiency of progenitor cell incorporation into the myocardium. Much work remains to be done in determining the relevant progenitor cell population and optimizing conditions for efficient differentiation and integration. Significant implications exist for treatment of pathologically damaged or aging myocardium since future interventional approaches will capitalize upon the use of cardiac stem cells as therapeutic reagents.
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Affiliation(s)
- Mark A Sussman
- SDSU Heart Institute, San Diego State University, Department of Biology, LS426, San Diego, California 98182, USA.
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19
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Bondarenko VE, Bett GCL, Rasmusson RL. A model of graded calcium release and L-type Ca2+ channel inactivation in cardiac muscle. Am J Physiol Heart Circ Physiol 2003; 286:H1154-69. [PMID: 14630639 DOI: 10.1152/ajpheart.00168.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have developed a model of Ca(2+) handling in ferret ventricular myocytes. This model includes a novel L-type Ca(2+) channel, detailed intracellular Ca(2+) movements, and graded Ca(2+)-induced Ca(2+) release (CICR). The model successfully reproduces data from voltage-clamp experiments, including voltage- and time-dependent changes in intracellular Ca(2+) concentration ([Ca(2+)](i)), L-type Ca(2+) channel current (I(CaL)) inactivation and recovery kinetics, and Ca(2+) sparks. The development of graded CICR is critically dependent on spatial heterogeneity and the physical arrangement of calcium channels in opposition to ryanodine-sensitive release channels. The model contains spatially distinct subsystems representing the subsarcolemmal regions where the junctional sarcoplasmic reticulum (SR) abuts the T-tubular membrane and where the L-type Ca(2+) channels and SR ryanodine receptors (RyRs) are localized. There are eight different types of subsystems in our model, with between one and eight L-type Ca(2+) channels distributed binomially. This model exhibits graded CICR and provides a quantitative description of Ca(2+) dynamics not requiring Monte-Carlo simulations. Activation of RyRs and release of Ca(2+) from the SR depend critically on Ca(2+) entry through L-type Ca(2+) channels. In turn, Ca(2+) channel inactivation is critically dependent on the release of stored intracellular Ca(2+). Inactivation of I(CaL) depends on both transmembrane voltage and local [Ca(2+)](i) near the channel, which results in distinctive inactivation properties. The molecular mechanisms underlying many I(CaL) gating properties are unclear, but [Ca(2+)](i) dynamics clearly play a fundamental role.
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20
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Abstract
With aging there are changes in the cardiovascular system, which result in alterations in cardiovascular physiology. The changes in cardiovascular physiology must be differentiated from the effects of pathology, such as coronary artery disease, that occur with increasing frequency as age increases. The changes with age occur in everyone but not necessarily at the same rate, therefore accounting for the difference seen in some people between chronologic age and physiologic age. The changes in the cardiovascular system associated with aging are a decrease in elasticity and an increase in stiffness of the arterial system. This results in increased afterload on the left ventricle, an increase in systolic blood pressure, and left ventricular hypertrophy, as well as other changes in the left ventricular wall that prolong relaxation of the left ventricle in diastole. There is a dropout of atrial pacemaker cells resulting in a decrease in intrinsic heart rate. With fibrosis of the cardiac skeleton there is calcification at the base of the aortic valve and damage to the His bundle as it perforates the right fibrous trigone. Finally there is decreased responsiveness to beta adrenergic receptor stimulation, a decreased reactivity to baroreceptors and chemoreceptors, and an increase in circulating catecholamines. These changes set the stage for isolated systolic hypertension, diastolic dysfunction and heart failure, atrioventricular conduction defects, and aortic valve calcification, all diseases seen in the elderly.
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Affiliation(s)
- Melvin D Cheitlin
- University of California at San Francisco, Former Chief of Cardiology, San Francisco General Hospital, San Francisco, CA 94110, USA
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21
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Josephson IR, Guia A, Stern MD, Lakatta EG. Alterations in properties of L-type Ca channels in aging rat heart. J Mol Cell Cardiol 2002; 34:297-308. [PMID: 11945022 DOI: 10.1006/jmcc.2001.1512] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies of whole-cell L-type Ca currents in aging heart have demonstrated an increase in the peak Ca current magnitude in proportion to the increase in membrane area, and a slowing of the time course for inactivation. However, the single-channel mechanisms underlying this upregulation, and for the slowed inactivation are not known. We have therefore compared the properties of single L-type Ca channel currents recorded from ventricular myocytes obtained from young adult (3 month), adult (6-8 month) and aging (24 month) Wistar rats, using 5 m m Ba ions as the permeant ion. We report that the peak ensemble-averaged single Ca channel currents from aging heart (-280+/-57 fA) were enhanced compared to those from young adult (-137+/-16 fA), or adult hearts (-144+/-38 fA). This surprising result was related, in part, to an apparent increase in the number of active Ca channels per patch in aging (1.90+/-0.23) v young adult (1.33+/-0.19) or adult heart (1.50+/-0.2). Moreover, there was an increase in the time constant for inactivation of the ensemble-averaged Ca currents of aging (471+/-169 ms), compared with young adult (198+/-43 ms), or adult heart (196+/-32 ms). The aging-related changes were also traced to alterations in single Ca channel gating, including an increase in the average probability of being open, and an increase in the availability of single Ca currents in aging heart. In contrast, the unitary Ca current amplitude was unchanged with aging. These novel findings suggest that the compensatory increase in the L-type Ca currents during aging is a consequence of an apparent increase in both the number, and the activity of individual L-type Ca channels.
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Affiliation(s)
- Ira R Josephson
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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22
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Chapter 2 Calcium homeostasis and signaling in aging. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1566-3124(02)10014-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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23
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Yamaguchi M. Chapter 4 Impact of aging on calcium channels and pumps. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1566-3124(02)10016-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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24
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Pignier C, Potreau D. Characterization of nifedipine-resistant calcium current in neonatal rat ventricular cardiomyocytes. Am J Physiol Heart Circ Physiol 2000; 279:H2259-68. [PMID: 11045961 DOI: 10.1152/ajpheart.2000.279.5.h2259] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calcium current was recorded from ventricular cardiomyocytes of rats at various stages of postnatal development using the whole cell patch-clamp technique. In cultured 3-day-old neonatal cells, the current carried by Ca(2+) or Ba(2+) (5 mM) was not completely inhibited by 2 microM nifedipine. A residual current was activated in the same voltage range as the L-type, nifedipine-sensitive Ca(2+) current, but its steady-state inactivation was negatively shifted by 16 mV. This nifedipine-resistant calcium current was not further inhibited by other organic calcium current antagonists such as PN200-110, verapamil, and diltiazem nor by nickel, omega-conotoxin, or tetrodotoxin. It was completely blocked by cadmium and increased by isoproterenol and forskolin. This current was >20% of total calcium current in ventricular myocytes freshly isolated from neonatal rats, and it decreased during postnatal maturation, disappearing at the adult stage. This suggests that this current could be caused by an isoform of the L-type calcium channel expressed in a way that reflects the developmental stage of the rat heart.
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Affiliation(s)
- C Pignier
- Centre National de la Recherche Scientifique, UMR 6558, Laboratoire des Biomembranes et Signalisation Cellulaire, Faculty of Sciences, University of Poitiers, 86022 Poitiers cedex, France
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25
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Barbagallo M, Gupta RK, Dominguez LJ, Resnick LM. Cellular ionic alterations with age: relation to hypertension and diabetes. J Am Geriatr Soc 2000; 48:1111-6. [PMID: 10983912 DOI: 10.1111/j.1532-5415.2000.tb04788.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Cytosolic free calcium (Cai) and magnesium (Mgi) are vital to cellular homeostasis and function. OBJECTIVE To evaluate cellular divalent cations in normal subjects at different ages and their relationship to ion levels in essential hypertension and diabetes. DESIGN A cross-sectional study. SETTING A university hospital in New York. PARTICIPANTS A total of 103 subjects (32 older, 71.1 +/- 1.2 y/o, and 71 young/middle aged subjects, 51.1 +/- 2.3 y/o). INTERVENTION Oral glucose tolerance test. MEASUREMENTS 19F and 31P NMR spectroscopy were used to measure Cai and Mgi levels in erythrocytes from normal (>65 y/o, n = 11; <65 y/o, n = 26), hypertensive (EH) (>65 y/o, n = 9; <65 y/o, n = 30), and type 2 diabetic (DM) (>65 y/o, n = 12; <65 y/o, n = 15) subjects; these levels were also compared with glucose and insulin levels before and after oral glucose loading. RESULTS Fasting Mgi levels were lower (207 +/- 7.8 vs 236 +/- 7.5 microM; P < .05) and Cai higher (32.2 +/- 3.0 vs 20.3 +/- 1.8 nM; P < .05) in older than in younger normal subjects. For all normal subjects, the greater the age, the higher the Cai (r = 0.622, P = .004) and the lower the Mgi (r = -0.423; P = .011). However, no significant (P = NS) differences in Mgi or Cai levels were observed between older normal and young/middle-aged subjects with EH (Mgi = 189.7 +/- 5.9 vs 182.6 +/- 9.8 microM; Cai = 33.8 +/- 4.9 vs 35.6 +/- 4.0 nM) or DM (Mgi = 182.8 +/- 10.9 vs 180.8 +/- 8.1 microM; Cai = 33.6 +/- 4.3 vs 39.7 +/- 5.9 nM). Significant relationships were also found between cellular ion content, blood pressure, and glycemic indices. CONCLUSIONS Aging is associated with the onset of altered Cai and Mgi levels, indistinguishable from those observed in hypertension and diabetes, independent of age. We suggest that these ionic changes may be clinically significant, underlying the predisposition of older subjects to cardiovascular and metabolic diseases.
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Affiliation(s)
- M Barbagallo
- Institute of Internal Medicine and Geriatrics, University of Palermo, Italy
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26
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Yang B, Larson DF, Watson R. Age-related left ventricular function in the mouse: analysis based on in vivo pressure-volume relationships. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1906-13. [PMID: 10564146 DOI: 10.1152/ajpheart.1999.277.5.h1906] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our study compared left ventricular (LV) function between senescent and young adult mice through in situ pressure-volume loop analysis. Two groups of mice (n = 9 each), 6-mo-old and 16-mo-old (senescent) mice, were anesthetized with urethan and alpha-chloralose, and their LV were instrumented with a Millar 1.4-Fr conductance micromanometer catheter for the acquisition of the pressure-volume loops. The senescent mice had a significantly decreased contractile function related to load-dependent parameters, including stroke volume index, ejection fraction, cardiac output index, stroke work index, and maximum derivative of change in systolic pressure over time. The load-independent parameters, preload recruitable stroke work and the slope (end-systolic volume elastance) of the end-systolic pressure-volume relationship, were significantly decreased in the senescent mice. Heart rate and arterial elastance were not different between the two groups; however, the ventricular-to-vascular coupling ratio (ratio of elastance of artery to end-systolic volume elastance) was increased by threefold in the senescent mice (P < 0. 001). Thus there were significant decreases in contractile function in the senescent mouse heart that appeared to be related to reduced mechanical efficiency but not related to arterial elastance.
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Affiliation(s)
- B Yang
- Arizona Prevention Center, University of Arizona, Tucson, Arizona 85724, USA
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