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Al Kury LT, Chacar S, Alefishat E, Khraibi AA, Nader M. Structural and Electrical Remodeling of the Sinoatrial Node in Diabetes: New Dimensions and Perspectives. Front Endocrinol (Lausanne) 2022; 13:946313. [PMID: 35872997 PMCID: PMC9302195 DOI: 10.3389/fendo.2022.946313] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/14/2022] [Indexed: 11/14/2022] Open
Abstract
The sinoatrial node (SAN) is composed of highly specialized cells that mandate the spontaneous beating of the heart through self-generation of an action potential (AP). Despite this automaticity, the SAN is under the modulation of the autonomic nervous system (ANS). In diabetes mellitus (DM), heart rate variability (HRV) manifests as a hallmark of diabetic cardiomyopathy. This is paralleled by an impaired regulation of the ANS, and by a pathological remodeling of the pacemaker structure and function. The direct effect of diabetes on the molecular signatures underscoring this pathology remains ill-defined. The recent focus on the electrical currents of the SAN in diabetes revealed a repressed firing rate of the AP and an elongation of its tracing, along with conduction abnormalities and contractile failure. These changes are blamed on the decreased expression of ion transporters and cell-cell communication ports at the SAN (i.e., HCN4, calcium and potassium channels, connexins 40, 45, and 46) which further promotes arrhythmias. Molecular analysis crystallized the RGS4 (regulator of potassium currents), mitochondrial thioredoxin-2 (reactive oxygen species; ROS scavenger), and the calcium-dependent calmodulin kinase II (CaMKII) as metabolic culprits of relaying the pathological remodeling of the SAN cells (SANCs) structure and function. A special attention is given to the oxidation of CaMKII and the generation of ROS that induce cell damage and apoptosis of diabetic SANCs. Consequently, the diabetic SAN contains a reduced number of cells with significant infiltration of fibrotic tissues that further delay the conduction of the AP between the SANCs. Failure of a genuine generation of AP and conduction of their derivative waves to the neighboring atrial myocardium may also occur as a result of the anti-diabetic regiment (both acute and/or chronic treatments). All together, these changes pose a challenge in the field of cardiology and call for further investigations to understand the etiology of the structural/functional remodeling of the SANCs in diabetes. Such an understanding may lead to more adequate therapies that can optimize glycemic control and improve health-related outcomes in patients with diabetes.
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Affiliation(s)
- Lina T. Al Kury
- Department of Health Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates
- *Correspondence: Lina T. Al Kury, ; Moni Nader,
| | - Stephanie Chacar
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Eman Alefishat
- Department of Pharmacology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Department of Biopharmaceutics and Clinical Pharmacy, School of Pharmacy, The University of Jordan, Amman, Jordan
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Ali A. Khraibi
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Moni Nader
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- *Correspondence: Lina T. Al Kury, ; Moni Nader,
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Nantsupawat T, Wongcharoen W, Chattipakorn SC, Chattipakorn N. Effects of metformin on atrial and ventricular arrhythmias: evidence from cell to patient. Cardiovasc Diabetol 2020; 19:198. [PMID: 33234131 PMCID: PMC7687769 DOI: 10.1186/s12933-020-01176-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/15/2020] [Indexed: 12/23/2022] Open
Abstract
Metformin has been shown to have various cardiovascular benefits beyond its antihyperglycemic effects, including a reduction in stroke, heart failure, myocardial infarction, cardiovascular death, and all-cause mortality. However, the roles of metformin in cardiac arrhythmias are still unclear. It has been shown that metformin was associated with decreased incidence of atrial fibrillation in diabetic patients with and without myocardial infarction. This could be due to the effects of metformin on preventing the structural and electrical remodeling of left atrium via attenuating intracellular reactive oxygen species, activating 5′ adenosine monophosphate-activated protein kinase, improving calcium homeostasis, attenuating inflammation, increasing connexin-43 gap junction expression, and restoring small conductance calcium-activated potassium channels current. For ventricular arrhythmias, in vivo reports demonstrated that activation of 5′ adenosine monophosphate-activated protein kinase and phosphorylated connexin-43 by metformin played a key role in ischemic ventricular arrhythmias reduction. However, metformin failed to show anti-ventricular arrhythmia benefits in clinical trials. In this review, in vitro and in vivo reports regarding the effects of metformin on both atrial arrhythmias and ventricular arrhythmias are comprehensively summarized and presented. Consistent and controversial findings from clinical trials are also summarized and discussed. Due to limited numbers of reports, further studies are needed to elucidate the mechanisms and effects of metformin on cardiac arrhythmias. Furthermore, randomized controlled trials are needed to clarify effects of metformin on cardiac arrhythmias in human.
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Affiliation(s)
- Teerapat Nantsupawat
- Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Chiang Mai, 50200, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Wanwarang Wongcharoen
- Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Chiang Mai, 50200, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Chiang Mai, 50200, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Chiang Mai, 50200, Thailand. .,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand. .,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
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Flagg TP, Cazorla O, Remedi MS, Haim TE, Tones MA, Bahinski A, Numann RE, Kovacs A, Schaffer JE, Nichols CG, Nerbonne JM. Ca
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-Independent Alterations in Diastolic Sarcomere Length and Relaxation Kinetics in a Mouse Model of Lipotoxic Diabetic Cardiomyopathy. Circ Res 2009; 104:95-103. [DOI: 10.1161/circresaha.108.186809] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Thomas P. Flagg
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Olivier Cazorla
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Maria S. Remedi
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Todd E. Haim
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Michael A. Tones
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Anthony Bahinski
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Randal E. Numann
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Attila Kovacs
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Jean E. Schaffer
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Colin G. Nichols
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
| | - Jeanne M. Nerbonne
- From the Departments of Cell Biology and Physiology (T.P.F., M.S.R., C.G.N.), Molecular Biology and Pharmacology (J.M.N.), and Internal Medicine (A.K., J.E.S.), Washington University School of Medicine, St Louis, Mo; Institut National de la Santé et de la Recherche Médicale, U-637 (O.C.), Université Montpellier 1, Unité de Formation et de Recherche de Médecine, Montpellier, France; and Pfizer Global Research & Development (T.E.H., M.A.T., A.B., R.E.N.), Chesterfield, Mo
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