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Sun RL, Wang HH, Gui ZC, Shuang-Guo, Lin LB, Fan JX, Xue-Zhang, Mao BY, Liu G, Liu WZ, Yue RZ, Yin YL, Wang QQ, Li P. Protective effect of vitamin B 6 against doxorubicin-induced cardiotoxicity by modulating NHE1 expression. J Biochem Mol Toxicol 2023; 37:e23403. [PMID: 37701944 DOI: 10.1002/jbt.23403] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 03/24/2023] [Accepted: 06/08/2023] [Indexed: 09/14/2023]
Abstract
Doxorubicin (DOX) has been used to treat various types of cancer, but its application is limited due to its heart toxicity as well as other drawbacks. Chronic inhibition of Na+ /H+ exchanger (NHE1) reduces heart failure and reduces the production of reactive oxygen species (ROS); vitamin B6 (VitB6 ) has been demonstrated to have a crucial role in antioxidant mechanism. So, this study was designed to explore the effect of VitB6 supplement on the DOX-induced cardiotoxicity and to imply whether NHE1 is involved. Ultrasonic cardiogram analysis revealed that VitB6 supplement could alleviate DOX-induced cardiotoxicity; hematoxylin and eosin (HE) and Masson's staining further confirmed this effect. Furthermore, VitB6 supplement exhibited significant antioxidative stress and antiapoptosis effect, which was evidenced by decreased serum malondialdehyde (MDA) content and increased serum superoxide dismutase (SOD) content, and decreased Bcl-2-associated X protein/B-cell lymphoma-2 ratio, respectively. Collectively, VitB6 supplement may exert antioxidative and antiapoptosis effects to improve cardiac function by decreasing NHE1 expression and improve DOX-induced cardiotoxicity.
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Affiliation(s)
- Rui-Li Sun
- Henan Key Laboratory of Immunology and Targeted Drugs, Xinxiang Key Laboratory of Tumor Microenvironment and Immunotherapy, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Huan-Huan Wang
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Zi-Chen Gui
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shuang-Guo
- Hubei Key Laboratory of Diabetes and Angiopathy, Hubei University of Science and Technology, Xianning, China
| | - Lai-Biao Lin
- Sino-UK Joint Laboratory of Brain Function and Injury, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
- Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, China
| | - Jia-Xin Fan
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Xue-Zhang
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Bin-Yan Mao
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Geng Liu
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Wei-Zhen Liu
- Sino-UK Joint Laboratory of Brain Function and Injury, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
- Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, China
| | - Rui-Zhu Yue
- Sino-UK Joint Laboratory of Brain Function and Injury, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
- Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, China
| | - Ya-Ling Yin
- Sino-UK Joint Laboratory of Brain Function and Injury, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
- Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, China
| | - Qian-Qian Wang
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Peng Li
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang Key Laboratory of Vascular Remodeling Intervention and Molecular Targeted Therapy Drug Development, College of Pharmacy, Xinxiang Medical University, Xinxiang, China
- Hubei Key Laboratory of Diabetes and Angiopathy, Hubei University of Science and Technology, Xianning, China
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Andreadou I, Bell RM, Bøtker HE, Zuurbier CJ. SGLT2 inhibitors reduce infarct size in reperfused ischemic heart and improve cardiac function during ischemic episodes in preclinical models. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165770. [PMID: 32194159 DOI: 10.1016/j.bbadis.2020.165770] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 12/16/2022]
Abstract
The sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of effective drugs managing patients, who suffer from type 2 diabetes (T2D): Landmark clinical trials including EMPA-REG, CANVAS and Declare-TIMI have demonstrated that SGLT2 inhibitors reduce cardiovascular mortality and re-hospitalization for heart failure (HF) in patients with T2D. It is well established that there is a strong independent relationship among infarct size measured within 1 month after reperfusion and all-cause death and hospitalization for HF: The fact that cardiovascular mortality was significantly reduced with the SGLT2 inhibitors, fuels the assumption that this class of therapies may attenuate myocardial infarct size. Experimental evidence demonstrates that SGLT2 inhibitors exert cardioprotective effects in animal models of acute myocardial infarction through improved function during the ischemic episode, reduction of infarct size and a subsequent attenuation of heart failure development. The aim of the present review is to outline the current state of preclinical research in terms of myocardial ischemia/reperfusion injury (I/R) and infarct size for clinically available SGLT2 inhibitors and summarize some of the proposed mechanisms of action (lowering intracellular Na+ and Ca2+, NHE inhibition, STAT3 and AMPK activation, CamKII inhibition, reduced inflammation and oxidative stress) that may contribute to the unexpected beneficial cardiovascular effects of this class of compounds.
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Affiliation(s)
- Ioanna Andreadou
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, 15771 Athens, Greece.
| | - Robert M Bell
- The Hatter Cardiovascular Institute, University College London, London, United Kingdom
| | - Hans Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, Aarhus N, Denmark
| | - Coert J Zuurbier
- Amsterdam UMC, University of Amsterdam, Laboratory of Experimental Intensive Care and Anesthesiology, Department of Anesthesiology, Amsterdam Cardiovascular Sciences, Amsterdam Infection & Immunity, Meibergdreef 9, AZ, 1105 Amsterdam, the Netherlands.
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3
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Lavin Plaza B, Theodoulou I, Rashid I, Hajhosseiny R, Phinikaridou A, Botnar RM. Molecular Imaging in Ischemic Heart Disease. CURRENT CARDIOVASCULAR IMAGING REPORTS 2019; 12:31. [PMID: 31281564 PMCID: PMC6557873 DOI: 10.1007/s12410-019-9500-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Purpose of Review The purpose of this paper is to review current and new modalities to image key biological processes in ischemic heart disease and after myocardial infarction non-invasively. Recent Findings New imaging targets have been developed to detect and quantify myocardial damage after ischemia. Although positron emission tomography (PET) has been leading the development of new probes in the past, continuous improvements of magnetic resonance imaging (MRI) together with the development of new novel MRI contrast agents opens new research avenues including the combination of both PET and MRI to obtain anatomic, functional, and molecular information simultaneously, which is not possible from a single imaging session. Summary This review summarizes the state of art of non-invasive molecular imaging of the myocardium during ischemia and after myocardial infarction using PET and MRI. We also describe the different contrast agents that have been developed to image the different phases of cardiac healing and the biological processes associated with each of those phases. Importantly, here we focus on imaging of inflammation as it is the key biological process that orchestrates clearance of dead cells, tissue remodeling, cardiac repair, and future outcome. We also focus on clinical translation of some of the novel contrast agents that have been tested in patients and discuss the need for larger, multi-center patient studies to fully validate the applicability of new imaging probes.
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Affiliation(s)
- Begoña Lavin Plaza
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth wing, St Thomas Hospital, London, SE1 7EH UK
| | - Iakovos Theodoulou
- 2Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Imran Rashid
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth wing, St Thomas Hospital, London, SE1 7EH UK
| | - Reza Hajhosseiny
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth wing, St Thomas Hospital, London, SE1 7EH UK
| | - Alkystis Phinikaridou
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth wing, St Thomas Hospital, London, SE1 7EH UK
| | - Rene M Botnar
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth wing, St Thomas Hospital, London, SE1 7EH UK.,3Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
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Molecular imaging of cardiac remodelling after myocardial infarction. Basic Res Cardiol 2018; 113:10. [PMID: 29344827 PMCID: PMC5772148 DOI: 10.1007/s00395-018-0668-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 11/17/2017] [Accepted: 01/08/2018] [Indexed: 02/06/2023]
Abstract
Myocardial infarction and subsequent heart failure is a major health burden associated with significant mortality and morbidity in western societies. The ability of cardiac tissue to recover after myocardial infarction is affected by numerous complex cellular and molecular pathways. Unbalance or failure of these pathways can lead to adverse remodelling of the heart and poor prognosis. Current clinical cardiac imaging modalities assess anatomy, perfusion, function, and viability of the myocardium, yet do not offer any insight into the specific molecular pathways involved in the repair process. Novel imaging techniques allow visualisation of these molecular processes and may have significant diagnostic and prognostic values, which could aid clinical management. Single photon-emission tomography, positron-emission tomography, and magnetic resonance imaging are used to visualise various aspects of these molecular processes. Imaging probes are usually attached to radioisotopes or paramagnetic nanoparticles to specifically target biological processes such as: apoptosis, necrosis, inflammation, angiogenesis, and scar formation. Although the results from preclinical studies are promising, translating this work to a clinical environment in a valuable and cost-effective way is extremely challenging. Extensive evaluation evidence of diagnostic and prognostic values in multi-centre clinical trials is still required.
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5
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Clancy CE, Chen-Izu Y, Bers DM, Belardinelli L, Boyden PA, Csernoch L, Despa S, Fermini B, Hool LC, Izu L, Kass RS, Lederer WJ, Louch WE, Maack C, Matiazzi A, Qu Z, Rajamani S, Rippinger CM, Sejersted OM, O'Rourke B, Weiss JN, Varró A, Zaza A. Deranged sodium to sudden death. J Physiol 2015; 593:1331-45. [PMID: 25772289 DOI: 10.1113/jphysiol.2014.281204] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/14/2014] [Indexed: 12/19/2022] Open
Abstract
In February 2014, a group of scientists convened as part of the University of California Davis Cardiovascular Symposium to bring together experimental and mathematical modelling perspectives and discuss points of consensus and controversy on the topic of sodium in the heart. This paper summarizes the topics of presentation and discussion from the symposium, with a focus on the role of aberrant sodium channels and abnormal sodium homeostasis in cardiac arrhythmias and pharmacotherapy from the subcellular scale to the whole heart. Two following papers focus on Na(+) channel structure, function and regulation, and Na(+)/Ca(2+) exchange and Na(+)/K(+) ATPase. The UC Davis Cardiovascular Symposium is a biannual event that aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The focus on Na(+) in the 2014 symposium stemmed from the multitude of recent studies that point to the importance of maintaining Na(+) homeostasis in the heart, as disruption of homeostatic processes are increasingly identified in cardiac disease states. Understanding how disruption in cardiac Na(+)-based processes leads to derangement in multiple cardiac components at the level of the cell and to then connect these perturbations to emergent behaviour in the heart to cause disease is a critical area of research. The ubiquity of disruption of Na(+) channels and Na(+) homeostasis in cardiac disorders of excitability and mechanics emphasizes the importance of a fundamental understanding of the associated mechanisms and disease processes to ultimately reveal new targets for human therapy.
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Affiliation(s)
- Colleen E Clancy
- Department of Pharmacology, University of California, Davis, Genome Building Rm 3503, Davis, CA, 95616-8636, USA
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6
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Effects of intravenous cariporide on release of norepinephrine and myoglobin during myocardial ischemia/reperfusion in rabbits. Life Sci 2014; 114:102-6. [DOI: 10.1016/j.lfs.2014.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/14/2014] [Accepted: 08/08/2014] [Indexed: 11/20/2022]
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7
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Hu YJ, Wang YD, Tan FQ, Yang WX. Regulation of paracellular permeability: factors and mechanisms. Mol Biol Rep 2013; 40:6123-42. [PMID: 24062072 DOI: 10.1007/s11033-013-2724-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 09/14/2013] [Indexed: 12/20/2022]
Abstract
Epithelial permeability is composed of transcellular permeability and paracellular permeability. Paracellular permeability is controlled by tight junctions (TJs). Claudins and occludin are two major transmembrane proteins in TJs, which directly determine the paracellular permeability to different ions or large molecules. Intracellular signaling pathways including Rho/Rho-associated protein kinase, protein kinase Cs, and mitogen-activated protein kinase, modulate the TJ proteins to affect paracellular permeability in response for diverse stimuli. Cytokines, growth factors and hormones in organism can regulate the paracellular permeability via signaling pathway. The transcellular transporters such as Na-K-ATPase, Na(+)-coupled transporters and chloride channels, can interact with paracellular transport and regulate the TJs. In this review, we summarized the factors affecting paracellular permeability and new progressions of the related mechanism in recent studies, and pointed out further research areas.
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Affiliation(s)
- Yan-Jun Hu
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 310006, People's Republic of China
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8
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Romero MF, Chen AP, Parker MD, Boron WF. The SLC4 family of bicarbonate (HCO₃⁻) transporters. Mol Aspects Med 2013; 34:159-82. [PMID: 23506864 DOI: 10.1016/j.mam.2012.10.008] [Citation(s) in RCA: 236] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 08/28/2012] [Indexed: 01/13/2023]
Abstract
The SLC4 family consists of 10 genes (SLC4A1-5; SLC4A7-11). All encode integral membrane proteins with very similar hydropathy plots-consistent with 10-14 transmembrane segments. Nine SLC4 members encode proteins that transport HCO3(-) (or a related species, such as CO3(2-)) across the plasma membrane. Functionally, eight of these proteins fall into two major groups: three Cl-HCO3 exchangers (AE1-3) and five Na(+)-coupled HCO3(-) transporters (NBCe1, NBCe2, NBCn1, NBCn2, NDCBE). Two of the Na(+)-coupled transporters (NBCe1, NBCe2) are electrogenic; the other three Na(+)-coupled HCO3(-) transporters and all three AEs are electroneutral. In addition, two other SLC4 members (AE4, SLC4A9 and BTR1, SLC4A11) do not yet have a firmly established function. Most, though not all, SLC4 members are functionally inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS). SLC4 proteins play important roles many modes of acid-base homeostasis: the carriage of CO2 by erythrocytes, the transport of H(+) or HCO3(-) by several epithelia, as well as the regulation of cell volume and intracellular pH.
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Affiliation(s)
- Michael F Romero
- Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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9
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Walls MC, Verhaert D, Min JK, Raman SV. Myocardial edema imaging in acute coronary syndromes. J Magn Reson Imaging 2012; 34:1243-50. [PMID: 22102557 DOI: 10.1002/jmri.22737] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Acute coronary syndromes (ACS) continue to be the most common morbid condition of industrialized nations. The advent of and technical improvements in revascularization and medical therapy have led to a steady decline in mortality rates. However, many patients who suffer unstable angina or myocardial infarction require further testing and risk stratification to guide therapeutic selection and prognosis assignment. Myocardial edema imaging with cardiac magnetic resonance (CMR) affords the ability to define the amount of myocardium at risk, refine estimates of prognosis and provide guidance for therapies with excellent sensitivity compared with standard clinical markers. This review will discuss the rationale for edema imaging, how it is performed using CMR, and potential clinical applications.
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10
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Moreno JD, Clancy CE. Pathophysiology of the cardiac late Na current and its potential as a drug target. J Mol Cell Cardiol 2011; 52:608-19. [PMID: 22198344 DOI: 10.1016/j.yjmcc.2011.12.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/30/2011] [Accepted: 12/07/2011] [Indexed: 12/19/2022]
Abstract
A pathological increase in the late component of the cardiac Na(+) current, I(NaL), has been linked to disease manifestation in inherited and acquired cardiac diseases including the long QT variant 3 (LQT3) syndrome and heart failure. Disruption in I(NaL) leads to action potential prolongation, disruption of normal cellular repolarization, development of arrhythmia triggers, and propensity to ventricular arrhythmia. Attempts to treat arrhythmogenic sequelae from inherited and acquired syndromes pharmacologically with common Na(+) channel blockers (e.g. flecainide, lidocaine, and amiodarone) have been largely unsuccessful. This is due to drug toxicity and the failure of most current drugs to discriminate between the peak current component, chiefly responsible for single cell excitability and propagation in coupled tissue, and the late component (I(NaL)) of the Na(+) current. Although small in magnitude as compared to the peak Na(+) current (~1-3%), I(NaL) alters action potential properties and increases Na(+) loading in cardiac cells. With the increasing recognition that multiple cardiac pathological conditions share phenotypic manifestations of I(NaL) upregulation, there has been renewed interest in specific pharmacological inhibition of I(Na). The novel antianginal agent ranolazine, which shows a marked selectivity for late versus peak Na(+) current, may represent a novel drug archetype for targeted reduction of I(NaL). This article aims to review common pathophysiological mechanisms leading to enhanced I(NaL) in LQT3 and heart failure as prototypical disease conditions. Also reviewed are promising therapeutic strategies tailored to alter the molecular mechanisms underlying I(Na) mediated arrhythmia triggers.
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Affiliation(s)
- Jonathan D Moreno
- Tri-Institutional MD-PhD Program, Weill Cornell Medical College/The Rockefeller University/Sloan-Kettering Cancer Institute, New York, NY 10021, USA
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11
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Leineweber K, Heusch G, Schulz R. Regulation and Role of the Presynaptic and Myocardial Na+/H+Exchanger NHE1: Effects on the Sympathetic Nervous System in Heart Failure. ACTA ACUST UNITED AC 2007; 25:123-31. [PMID: 17614935 DOI: 10.1111/j.1527-3466.2007.00010.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In acute myocardial ischemia and in chronic heart failure, sympathetic activation with excessive norepinephrine (NE) release from and reduced NE reuptake into sympathetic nerve endings is a prominent cause of arrhythmias and cardiac dysfunction. The Na(+)/H(+) exchanger NHE1 is the predominant isoform in the heart. It contributes to cellular acid-base balance, and electrolyte, and volume homeostasis, and is activated in response to intracellular acidosis and/or activation of guanine nucleotide binding (G) protein-coupled receptors. NHE1 mediates its signaling via protein kinases A (PKA) or C (PKC). In cardiomyocytes, NHE1 is restricted to specialized membrane domains, where it regulates the activity of pH-sensitive proteins and modulates the driving force of the Na(+)/Ca(2+) exchanger. During acute ischemia/reperfusion and in heart failure the activity/amount of NHE1 is increased, leading to intracellular Ca(2+) overload and promoting structural (apoptosis, hypertrophy) and functional (arrhythmias, hypercontraction) myocardial damage. In sympathetic nerve endings, increased NHE1 activity results in the accumulation of axoplasmic Na(+) that diminishes the inward and/or favors the outward transport of NE via the neuronal norepinephrine transporter (NET). The increased NE levels within the nerve-muscle junction facilitate the sustained stimulation of myocardial alpha- and beta-adrenoceptors (ARs), which in turn aggravate the increases in myocardial NHE1 activity and the associated deleterious effects. Furthermore, the responsiveness of the beta-AR declines overtime, which results in further release of NE, initiating a vicious cycle. Accordingly, NHE1 is a potential candidate for targeted intervention to suppress this feedback loop.
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Affiliation(s)
- Kirsten Leineweber
- Institute of Pathophysiology, University of Essen School of Medicine, D-45122 Essen, Germany.
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12
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Belardinelli L, Shryock JC, Fraser H. Inhibition of the late sodium current as a potential cardioprotective principle: effects of the late sodium current inhibitor ranolazine. Heart 2006; 92 Suppl 4:iv6-iv14. [PMID: 16775092 PMCID: PMC1861317 DOI: 10.1136/hrt.2005.078790] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pathological conditions linked to imbalances in oxygen supply and demand (for example, ischaemia, hypoxia and heart failure) are associated with disruptions in intracellular sodium ([Na(+)](i)) and calcium ([Ca(2+)](i)) concentration homeostasis of myocardial cells. A decreased efflux or increased influx of sodium may cause cellular sodium overload. Sodium overload is followed by an increased influx of calcium through sodium-calcium exchange. Failure to maintain the homeostasis of [Na(+)](i) and [Ca(2+)](i) leads to electrical instability (arrhythmias), mechanical dysfunction (reduced contractility and increased diastolic tension) and mitochondrial dysfunction. These events increase ATP hydrolysis and decrease ATP formation and, if left uncorrected, they cause cell injury and death. The relative contributions of various pathways (sodium channels, exchangers and transporters) to the rise in [Na(+)](i) remain a matter of debate. Nevertheless, both the sodium-hydrogen exchanger and abnormal sodium channel conductance (that is, increased late sodium current (I(Na))) are likely to contribute to the rise in [Na(+)](i). The focus of this review is on the role of the late (sustained/persistent) I(Na) in the ionic disturbances associated with ischaemia/hypoxia and heart failure, the consequences of these ionic disturbances, and the cardioprotective effects of the antianginal and anti-ischaemic drug ranolazine. Ranolazine selectively inhibits late I(Na), reduces [Na(+)](i)-dependent calcium overload and attenuates the abnormalities of ventricular repolarisation and contractility that are associated with ischaemia/reperfusion and heart failure. Thus, inhibition of late I(Na) can reduce [Na(+)](i)-dependent calcium overload and its detrimental effects on myocardial function.
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Affiliation(s)
- L Belardinelli
- Department of Pharmacological Sciences, CV Therapeutics, Inc, 3172 Porter Dr, Palo Alto, CA 94304, USA.
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13
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Gursahani HI, Schaefer S. Acidification reduces mitochondrial calcium uptake in rat cardiac mitochondria. Am J Physiol Heart Circ Physiol 2004; 287:H2659-65. [PMID: 15308476 DOI: 10.1152/ajpheart.00344.2004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac ischemia-reperfusion (I/R) injury is accompanied by intracellular acidification that can lead to cytosolic and mitochondrial calcium overload. However, the effect of cytosolic acidification on mitochondrial pH (pHm) and mitochondrial Ca2+(Cam2+) handling is not well understood. In the present study, we tested the hypothesis that changes in pHmduring cytosolic acidification can modulate Cam2+handling in cardiac mitochondria. pHmwas measured in permeabilized rat ventricular myocytes with the use of confocal microscopy and the pH-sensitive fluorescent probe carboxyseminaphthorhodafluor-1. The contributions of the mitochondrial Na+/H+exchanger (NHEm) and the K+/H+exchanger (KHEm) to pHmregulation were evaluated using acidification and recovery protocols to mimic the changes in pH observed during I/R. Cam2+transport in isolated mitochondria was measured using spectrophotometry and fluorimetry, and the mitochondrial membrane potential was measured using a tetraphenylphosphonium electrode. Cytosolic acidification (pH 6.8) resulted in acidification of mitochondria. The degree of mitochondrial acidification and recovery was found to be largely dependent on the activity of the KHEm. However, the NHEmwas observed to contribute to the recovery of pHmfollowing acidification in K+-free solutions as well as the maintenance of pHmduring respiratory inhibition. Acidification resulted in mitochondrial depolarization and a decrease in the rate of net Cam2+uptake, whereas restoration of pH following acidification increased Cam2+uptake. These findings are consistent with an important role for cytosolic acidification in determining pHmand Cam2+handling in cardiac mitochondria under conditions of Ca2+overload. Consequently, interventions that alter pHmcan limit Cam2+overload and injury during I/R.
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Affiliation(s)
- Hema I Gursahani
- Division of Cardiovascular Medicine, One Shields Ave., TB 172, Bioletti Way, Univ. of California, Davis, Davis, CA 95616, USA
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14
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Romero MF, Fulton CM, Boron WF. The SLC4 family of HCO 3 - transporters. Pflugers Arch 2004; 447:495-509. [PMID: 14722772 DOI: 10.1007/s00424-003-1180-2] [Citation(s) in RCA: 336] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2003] [Accepted: 09/05/2003] [Indexed: 12/21/2022]
Abstract
The SLC4 family consists of ten genes. All appear to encode integral membrane proteins with very similar hydropathy plots-consistent with the presence of 10-14 transmembrane segments. At least eight SLC4 members encode proteins that transport HCO(3)(-) (or a related species, such as CO(3)(2-)) across the plasma membrane. Functionally, these eight proteins fall into two major groups: three Cl-HCO(3) exchangers (AE1-3) and five Na(+)-coupled HCO(3)(-) transporters (NBCe1, NBCe2, NBCn1, NDCBE, NCBE). Two of the Na(+)-coupled HCO(3)(- )transporters (NBCe1, NBCe2) are electrogenic; the other three Na(+)-coupled HCO(3)(-) transporters and all three AEs are electroneutral. At least NDCBE transports Cl(-) in addition to Na(+) and HCO(3)(-). Whether NCBE transports Cl(-)-in addition to Na(+) and HCO(3)(-)-is unsettled. In addition, two other SLC4 members (AE4 and BTR1) do not yet have a firmly established function; on the basis of homology, they fall between the two major groups. A characteristic of many, though not all, SLC4 members is inhibition by 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS). SLC4 gene products play important roles in the carriage of CO(2) by erythrocytes, the absorption or secretion of H(+) or HCO(3)(-) by several epithelia, as well as the regulation of cell volume and intracellular pH.
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Affiliation(s)
- Michael F Romero
- Departments of Physiology and Biophysics and Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4970, USA.
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