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Amione C, Giunti S, Fornengo P, Soedamah-Muthu SS, Chaturvedi N, Fuller JH, Barutta F, Gruden G, Bruno G. Incidence of prolonged QTc and severe hypoglycemia in type 1 diabetes: the EURODIAB Prospective Complications Study. Acta Diabetol 2017. [PMID: 28634852 DOI: 10.1007/s00592-017-1018-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
AIMS To assess the independent role of severe hypoglycemia on 7-year cumulative incidence of prolonged QTc in a large cohort of patients with type 1 diabetes. METHODS People with type 1 diabetes recruited by the EURODIAB Prospective Complications Study who had normal QTc were examined at baseline and after 7 years with standardized methods (n = 1415; mean age ± SD 32.1 ± 9.6 years; diabetes duration 14.2 ± 8.8 years). Hypoglycemic episodes were assessed by a questionnaire. QTc was calculated according to Bazett's formula. In logistic regression analysis, we examined the role of severe hypoglycemia (none, 1-2, or 3 and more episodes/year) on the cumulative incidence of prolonged QTc, independently of age, sex, HbA1c, blood pressure, BMI, physical activity, distal symmetrical and autonomic neuropathy. RESULTS In total, 264/1415 (17%) patients had incident prolonged QTc. Compared to those with persistently normal QTc, a greater proportion of incident cases had 3 and more hypoglycemic episodes at baseline (16.3 vs 11.2%, p = 0.03) and after 7 years (15.2 vs 9.6%, p = 0.01). In logistic regression analysis, 3 or more episodes of severe hypoglycemia at baseline did not increase cumulative incidence of prolonged QTc (OR 1.34, 95% CI 0.88-2.03). By contrast, severe hypoglycemia at the follow-up examination was associated with higher incidence of QTc prolongation (OR 1.68, 1.09-2.58), which reverted to not significant after adjustment for diabetic neuropathy. CONCLUSIONS Severe hypoglycemia was not associated with incidence QTc prolongation in type 1 diabetic patients from the EURODIAB PCS.
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Affiliation(s)
- Cristina Amione
- Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Turin, Italy
| | - Sara Giunti
- Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Turin, Italy
| | - Paolo Fornengo
- Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Turin, Italy
| | | | - Nish Chaturvedi
- Department of Epidemiology and Public-Health, University College London, London, UK
| | - J H Fuller
- Department of Epidemiology and Public-Health, University College London, London, UK
| | - Federica Barutta
- Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Turin, Italy
| | - Gabriella Gruden
- Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Turin, Italy
| | - Graziella Bruno
- Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Turin, Italy.
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52
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Fanaroff AC, James SK, Weisz G, Prather K, Anstrom KJ, Mark DB, Ben-Yehuda O, Alexander KP, Stone GW, Ohman EM. Ranolazine After Incomplete Percutaneous Coronary Revascularization in Patients With Versus Without Diabetes Mellitus: RIVER-PCI Trial. J Am Coll Cardiol 2017; 69:2304-2313. [PMID: 28473136 DOI: 10.1016/j.jacc.2017.02.056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 02/27/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Chronic angina is more common in patients with diabetes mellitus (DM) with poor glucose control. Ranolazine both treats chronic angina and improves glucose control. OBJECTIVES This study sought to examine ranolazine's antianginal effect in relation to glucose control. METHODS The authors performed a secondary analysis of the RIVER-PCI (Ranolazine in Patients with Incomplete Revascularization after Percutaneous Coronary Intervention) trial, a clinical trial in which 2,604 patients with chronic angina and incomplete revascularization following percutaneous coronary intervention were randomized to ranolazine versus placebo. Mixed-effects models were used to compare the effects of ranolazine versus placebo on glycosylated hemoglobin (HbA1c) at 6- and 12-month follow-up. Interaction between baseline HbA1c and ranolazine's effect on Seattle Angina Questionnaire angina frequency at 6 and 12 months was tested. RESULTS Overall, 961 patients (36.9%) had DM at baseline. Compared with placebo, ranolazine significantly decreased HbA1c by 0.42 ± 0.08% (adjusted mean difference ± SE) and 0.44 ± 0.08% from baseline to 6 and 12 months, respectively, in DM patients, and by 0.19 ± 0.02% and 0.20 ± 0.02% at 6 and 12 months, respectively, in non-DM patients. Compared with placebo, ranolazine significantly reduced Seattle Angina Questionnaire angina frequency at 6 months among DM patients but not at 12 months. The reductions in angina frequency were numerically greater among patients with baseline HbA1c ≥7.5% than those with HbA1c <7.5% (interaction p = 0.07). CONCLUSIONS In patients with DM and chronic angina with incomplete revascularization after percutaneous coronary intervention, ranolazine's effect on glucose control and angina at 6 months was proportionate to baseline HbA1c, but the effect on angina dissipated by 12 months.
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Affiliation(s)
- Alexander C Fanaroff
- Department of Medicine, Division of Cardiology, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
| | - Stefan K James
- Department of Medical Sciences and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden
| | - Giora Weisz
- Division of Cardiology, Columbia University, New York, New York; Cardiovascular Research Foundation, New York, New York; Department of Cardiology, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Kristi Prather
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
| | - Kevin J Anstrom
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
| | - Daniel B Mark
- Department of Medicine, Division of Cardiology, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
| | | | - Karen P Alexander
- Department of Medicine, Division of Cardiology, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina.
| | - Gregg W Stone
- Division of Cardiology, Columbia University, New York, New York; Cardiovascular Research Foundation, New York, New York
| | - E Magnus Ohman
- Department of Medicine, Division of Cardiology, Duke University Medical Center, Durham, North Carolina; Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
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53
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Lu Z, Lense L, Sharma M, Shah A, Luu Y, Cardinal L, Faro J, Kaell A. Prevalence of QT prolongation and associated LVEF changes in diabetic patients over a four-year retrospective time period. J Community Hosp Intern Med Perspect 2017. [PMID: 28638571 PMCID: PMC5473188 DOI: 10.1080/20009666.2017.1320203] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aim: To evaluate the prevalence and longitudinal changes of prolonged QTc in DM patients admitted to our community hospital, and to determine, if any, its correlation with changes of left ventricular ejection fraction (LVEF). Methods: A retrospective chart review of patients with Type 1 (T1DM) and Type 2 (T2DM) with at least two admissions during a four-year period was performed to identify QTc interval, and LVEF, as measured on transthoracic echocardiogram. Changes in QTc and LVEF between patient hospital admissions were compared. Results: A prolonged QTc interval was found in 66.7% (n = 24) of type 1 and 51.3% (n = 154) type 2 diabetic patients. The QTc interval is progressively increased in both type 1 and type 2 diabetes during follow-up, although it did not reach statistical significance. A total of 62% patients (23 out 37 patients) had a reduction of LVEF during follow-up. Conclusion and Discussion: High prevalence of QTc prolongation was confirmed in hospitalized patients with in both T1DM and T2DM. Significant reduction of LVEF correlated with QTc prolongation over a mean of 17.3 months in T2DM patients, and may have implications for interventions. Abbreviations CHF: Congestive heart failure LVEF: Left ventricular ejection fraction
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Affiliation(s)
- Zhongju Lu
- Department of Internal Medicine, John T. Mather Memorial Hospital, Port Jefferson, NY, USA
| | - Lloyd Lense
- Division of Cardiology, Stony Brook University Hospital, Stony Brook, NY, USA
| | - Mohit Sharma
- Department of Internal Medicine, John T. Mather Memorial Hospital, Port Jefferson, NY, USA
| | - Ankit Shah
- Department of Internal Medicine, John T. Mather Memorial Hospital, Port Jefferson, NY, USA
| | - Ying Luu
- Department of Internal Medicine, John T. Mather Memorial Hospital, Port Jefferson, NY, USA
| | - Lucien Cardinal
- Department of Internal Medicine, John T. Mather Memorial Hospital, Port Jefferson, NY, USA
| | - Joan Faro
- Department of Internal Medicine, John T. Mather Memorial Hospital, Port Jefferson, NY, USA
| | - Alan Kaell
- Department of Internal Medicine, John T. Mather Memorial Hospital, Port Jefferson, NY, USA
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54
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Cohen IS, Lin RZ, Ballou LM. Acquired long QT syndrome and phosphoinositide 3-kinase. Trends Cardiovasc Med 2017; 27:451-459. [PMID: 28687226 DOI: 10.1016/j.tcm.2017.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 01/08/2023]
Abstract
While it is well known that mutation of several different ion channels can cause congenital long QT syndrome, block of IKr is widely thought to be responsible for most cases of drug-induced acquired long QT syndrome (aLQTS). In this article, we review evidence supporting another cause of aLQTS due to inhibition of phosphoinositide 3-kinase (PI3K) signaling. Inhibition of PI3K affects multiple plateau currents, reducing IKr, IKs, and ICaL while increasing the persistent sodium current (INaP). The effects of PI3K inhibitors develop slowly, requiring hours to days to reach steady state. Dofetilide and terfenadine, an antihistamine on which much of the original IKr hypothesis was based, are among the many drugs that inhibit the PI3K pathway. Reduced PI3K signaling may also play a role in aLQTS associated with diabetes. Drug safety testing to identify aLQTS risk may be improved by examining PI3K-dependent effects that develop over time.
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Affiliation(s)
- Ira S Cohen
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY.
| | - Richard Z Lin
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY; Medical Service, Northport VA Medical Center, Northport, NY
| | - Lisa M Ballou
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY
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55
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Abstract
The QT interval on surface electrocardiograms provides a model of a multicomponent integrated readout of many biological systems, including ion channels, modulatory subunits, signaling systems that modulate their activity, and mechanisms that regulate the expression of their responsible genes. The problem of drug exposure causing exaggerated QT interval prolongation and torsades de pointes highlights the multicomponent nature of cardiac repolarization and the way in which simple perturbations can yield exaggerated responses. Future directions will involve cellular approaches coupled to evolving technologies that can interrogate multicellular systems and provide a sophisticated view of mechanisms in this previously idiosyncratic drug reaction.
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Affiliation(s)
- Dan M Roden
- Oates Institute for Experimental Therapeutics, Vanderbilt University School of Medicine, 1285 MRB IV, Nashville, TN 37232-0575, USA.
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56
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Abstract
Voltage-gated sodium channels (VGSCs) are critical determinants of excitability. The properties of VGSCs are thought to be tightly controlled. However, VGSCs are also subjected to extensive modifications. Multiple posttranslational modifications that covalently modify VGSCs in neurons and muscle have been identified. These include, but are not limited to, phosphorylation, ubiquitination, palmitoylation, nitrosylation, glycosylation, and SUMOylation. Posttranslational modifications of VGSCs can have profound impact on cellular excitability, contributing to normal and abnormal physiology. Despite four decades of research, the complexity of VGSC modulation is still being determined. While some modifications have similar effects on the various VGSC isoforms, others have isoform-specific interactions. In addition, while much has been learned about how individual modifications can impact VGSC function, there is still more to be learned about how different modifications can interact. Here we review what is known about VGSC posttranslational modifications with a focus on the breadth and complexity of the regulatory mechanisms that impact VGSC properties.
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Affiliation(s)
- Zifan Pei
- Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.,Department of Pharmacology and Toxicology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA
| | - Yanling Pan
- Medical Neuroscience Graduate Program, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA
| | - Theodore R Cummins
- Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA. .,Department of Pharmacology and Toxicology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA. .,Medical Neuroscience Graduate Program, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
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57
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Monnerat G, Alarcón ML, Vasconcellos LR, Hochman-Mendez C, Brasil G, Bassani RA, Casis O, Malan D, Travassos LH, Sepúlveda M, Burgos JI, Vila-Petroff M, Dutra FF, Bozza MT, Paiva CN, Carvalho AB, Bonomo A, Fleischmann BK, de Carvalho ACC, Medei E. Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice. Nat Commun 2016; 7:13344. [PMID: 27882934 PMCID: PMC5123037 DOI: 10.1038/ncomms13344] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 09/24/2016] [Indexed: 02/08/2023] Open
Abstract
Diabetes mellitus (DM) encompasses a multitude of secondary disorders, including heart disease. One of the most frequent and potentially life threatening disorders of DM-induced heart disease is ventricular tachycardia (VT). Here we show that toll-like receptor 2 (TLR2) and NLRP3 inflammasome activation in cardiac macrophages mediate the production of IL-1β in DM mice. IL-1β causes prolongation of the action potential duration, induces a decrease in potassium current and an increase in calcium sparks in cardiomyocytes, which are changes that underlie arrhythmia propensity. IL-1β-induced spontaneous contractile events are associated with CaMKII oxidation and phosphorylation. We further show that DM-induced arrhythmias can be successfully treated by inhibiting the IL-1β axis with either IL-1 receptor antagonist or by inhibiting the NLRP3 inflammasome. Our results establish IL-1β as an inflammatory connection between metabolic dysfunction and arrhythmias in DM.
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MESH Headings
- Action Potentials
- Animals
- Antirheumatic Agents/pharmacology
- Arrhythmias, Cardiac/etiology
- Arrhythmias, Cardiac/immunology
- Arrhythmias, Cardiac/metabolism
- Calcium/metabolism
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Caspase 1/metabolism
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/immunology
- Diabetes Mellitus, Experimental/metabolism
- Inflammasomes/antagonists & inhibitors
- Interleukin 1 Receptor Antagonist Protein/pharmacology
- Interleukin-1beta/genetics
- Interleukin-1beta/immunology
- Interleukin-1beta/metabolism
- Macrophages/immunology
- Mice
- Mice, Transgenic
- Myocardial Contraction
- Myocytes, Cardiac/immunology
- Myocytes, Cardiac/metabolism
- NLR Family, Pyrin Domain-Containing 3 Protein/antagonists & inhibitors
- NLR Family, Pyrin Domain-Containing 3 Protein/genetics
- NLR Family, Pyrin Domain-Containing 3 Protein/immunology
- Potassium/metabolism
- Receptors, Interleukin-1/antagonists & inhibitors
- Receptors, Interleukin-1/genetics
- Receptors, Interleukin-1/immunology
- Tachycardia, Ventricular/etiology
- Tachycardia, Ventricular/immunology
- Tachycardia, Ventricular/metabolism
- Toll-Like Receptor 2/genetics
- Toll-Like Receptor 2/immunology
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Affiliation(s)
- Gustavo Monnerat
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Micaela L. Alarcón
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Luiz R. Vasconcellos
- LIRS-Laboratory of Immunoreceptors and Signaling, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Camila Hochman-Mendez
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Guilherme Brasil
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Rosana A. Bassani
- Center for Biomedical Engineering, University of Campinas, Campinas 13.083-970, Brazil
| | - Oscar Casis
- Departamento de Fisiología, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria, Spain
| | - Daniela Malan
- Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn D-53127, Germany
| | - Leonardo H. Travassos
- LIRS-Laboratory of Immunoreceptors and Signaling, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Marisa Sepúlveda
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Juan Ignacio Burgos
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Martin Vila-Petroff
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Fabiano F. Dutra
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Marcelo T. Bozza
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Claudia N. Paiva
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Adriana Bastos Carvalho
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Adriana Bonomo
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- FIOCANCER/ VPPLR/FIOCRUZ, FIOCRUZ-Manguinhos, Rio de Janeiro 21040-360, Brazil
| | - Bernd K. Fleischmann
- Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn D-53127, Germany
| | - Antonio Carlos Campos de Carvalho
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- National Center for Structural Biology and Bioimaging—CENABIO/UFRJ, Rio de Janeiro 21941-902, Brazil
| | - Emiliano Medei
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- National Center for Structural Biology and Bioimaging—CENABIO/UFRJ, Rio de Janeiro 21941-902, Brazil
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Sorrentino A, Borghetti G, Zhou Y, Cannata A, Meo M, Signore S, Anversa P, Leri A, Goichberg P, Qanud K, Jacobson JT, Hintze TH, Rota M. Hyperglycemia induces defective Ca2+ homeostasis in cardiomyocytes. Am J Physiol Heart Circ Physiol 2016; 312:H150-H161. [PMID: 27881388 DOI: 10.1152/ajpheart.00737.2016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 11/21/2016] [Accepted: 11/21/2016] [Indexed: 01/03/2023]
Abstract
Diabetes and other metabolic conditions characterized by elevated blood glucose constitute important risk factors for cardiovascular disease. Hyperglycemia targets myocardial cells rendering ineffective mechanical properties of the heart, but cellular alterations dictating the progressive deterioration of cardiac function with metabolic disorders remain to be clarified. In the current study, we examined the effects of hyperglycemia on cardiac function and myocyte physiology by employing mice with high blood glucose induced by administration of streptozotocin, a compound toxic to insulin-producing β-cells. We found that hyperglycemia initially delayed the electrical recovery of the heart, whereas cardiac function became defective only after ~2 mo with this condition and gradually worsened with time. Prolonged hyperglycemia was associated with increased chamber dilation, thinning of the left ventricle (LV), and myocyte loss. Cardiomyocytes from hyperglycemic mice exhibited defective Ca2+ transients before the appearance of LV systolic defects. Alterations in Ca2+ transients involved enhanced spontaneous Ca2+ releases from the sarcoplasmic reticulum (SR), reduced cytoplasmic Ca2+ clearance, and declined SR Ca2+ load. These defects have important consequences on myocyte contraction, relaxation, and mechanisms of rate adaptation. Collectively, our data indicate that hyperglycemia alters intracellular Ca2+ homeostasis in cardiomyocytes, hindering contractile activity and contributing to the manifestation of the diabetic cardiomyopathy. NEW & NOTEWORTHY We have investigated the effects of hyperglycemia on cardiomyocyte physiology and ventricular function. Our results indicate that defective Ca2+ handling is a critical component of the progressive deterioration of cardiac performance of the diabetic heart.
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Affiliation(s)
- Andrea Sorrentino
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Giulia Borghetti
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Yu Zhou
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Antonio Cannata
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Marianna Meo
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Sergio Signore
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Piero Anversa
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.,Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Annarosa Leri
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.,Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Polina Goichberg
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Khaled Qanud
- Department of Physiology, New York Medical College, Valhalla, New York; and
| | - Jason T Jacobson
- Department of Physiology, New York Medical College, Valhalla, New York; and.,Department of Cardiology, Westchester Medical Center, Valhalla, New York
| | - Thomas H Hintze
- Department of Physiology, New York Medical College, Valhalla, New York; and
| | - Marcello Rota
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; .,Department of Physiology, New York Medical College, Valhalla, New York; and
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59
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Cardona K, Trenor B, Giles WR. Changes in Intracellular Na+ following Enhancement of Late Na+ Current in Virtual Human Ventricular Myocytes. PLoS One 2016; 11:e0167060. [PMID: 27875582 PMCID: PMC5119830 DOI: 10.1371/journal.pone.0167060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 11/08/2016] [Indexed: 12/19/2022] Open
Abstract
The slowly inactivating or late Na+ current, INa-L, can contribute to the initiation of both atrial and ventricular rhythm disturbances in the human heart. However, the cellular and molecular mechanisms that underlie these pro-arrhythmic influences are not fully understood. At present, the major working hypothesis is that the Na+ influx corresponding to INa-L significantly increases intracellular Na+, [Na+]i; and the resulting reduction in the electrochemical driving force for Na+ reduces and (may reverse) Na+/Ca2+ exchange. These changes increase intracellular Ca2+, [Ca2+]i; which may further enhance INa-L due to calmodulin-dependent phosphorylation of the Na+ channels. This paper is based on mathematical simulations using the O'Hara et al (2011) model of baseline or healthy human ventricular action potential waveforms(s) and its [Ca2+]i homeostasis mechanisms. Somewhat surprisingly, our results reveal only very small changes (≤ 1.5 mM) in [Na+]i even when INa-L is increased 5-fold and steady-state stimulation rate is approximately 2 times the normal human heart rate (i.e. 2 Hz). Previous work done using well-established models of the rabbit and human ventricular action potential in heart failure settings also reported little or no change in [Na+]i when INa-L was increased. Based on our simulations, the major short-term effect of markedly augmenting INa-L is a significant prolongation of the action potential and an associated increase in the likelihood of reactivation of the L-type Ca2+ current, ICa-L. Furthermore, this action potential prolongation does not contribute to [Na+]i increase.
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Affiliation(s)
- Karen Cardona
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Beatriz Trenor
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
- * E-mail:
| | - Wayne R. Giles
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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60
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Selker HP, Harris WS, Rackley CE, Marsh JB, Ruthazer R, Beshansky JR, Rashba EJ, Peter I, Opie LH. Very early administration of glucose-insulin-potassium by emergency medical service for acute coronary syndromes: Biological mechanisms for benefit in the IMMEDIATE Trial. Am Heart J 2016; 178:168-75. [PMID: 27502865 DOI: 10.1016/j.ahj.2016.03.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 03/31/2016] [Indexed: 10/21/2022]
Abstract
AIMS In the IMMEDIATE Trial, intravenous glucose-insulin-potassium (GIK) was started as early as possible for patients with suspected acute coronary syndrome by ambulance paramedics in communities. In the IMMEDIATE Biological Mechanism Cohort substudy, reported here, we investigated potential modes of GIK action on specific circulating metabolic components. Specific attention was given to suppression of circulating oxygen-wasting free fatty acids (FFAs) that had been posed as part of the early GIK action related to averting cardiac arrest. METHODS We analyzed the changes in plasma levels of FFA, glucose, C-peptide, and the homeostasis model assessment (HOMA) index. RESULTS With GIK, there was rapid suppression of FFA levels with estimated levels for GIK and placebo groups after 2 hours of treatment of 480 and 781 μmol/L (P<.0001), even while patterns of FFA saturation remained unchanged. There were no significant changes in the HOMA index in the GIK or placebo groups (HOMA index: placebo 10.93, GIK 12.99; P = .07), suggesting that GIK infusions were not countered by insulin resistance. Also, neither placebo nor GIK altered endogenous insulin secretion as reflected by unchanging C-peptide levels. CONCLUSION These mechanistic observations support the potential role of FFA suppression in very early cardioprotection by GIK. They also suggest that the IMMEDIATE Trial GIK formula is balanced with respect to its insulin and glucose composition, as it induced no endogenous insulin secretion.
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α1-Syntrophin Variant Identified in Drug-Induced Long QT Syndrome Increases Late Sodium Current. PLoS One 2016; 11:e0152355. [PMID: 27028743 PMCID: PMC4814026 DOI: 10.1371/journal.pone.0152355] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/14/2016] [Indexed: 12/19/2022] Open
Abstract
Drug-induced long-QT syndrome (diLQTS) is often due to drug block of IKr, especially in genetically susceptible patients with subclinical mutations in the IKr-encoding KCHN2. Few variants in the cardiac NaV1.5 Na+ channel complex have been associated with diLQTS. We tested whether a novel SNTA1 (α1-syntrophin) variant (p.E409Q) found in a patient with diLQTS increases late sodium current (INa-L), thereby providing a disease mechanism. Electrophysiological studies were performed in HEK293T cells co-expressing human NaV1.5/nNOS/PMCA4b with either wild type (WT) or SNTA1 variants (A390V-previously reported in congenital LQTS; and E409Q); and in adult rat ventricular cardiomyocytes infected with SNTA1 expressing adenoviruses (WT or one of the two SNTA1 variants). In HEK293T cells and in cardiomyocytes, there was no significant difference in the peak INa densities among the SNTA1 WT and variants. However, both variants increased INa-L (% of peak current) in HEK293T cells (0.58±0.10 in WT vs. 0.90±0.11 in A390V, p = 0.048; vs. 0.88±0.07 in E409Q, p = 0.023). In cardiomyocytes, INa-L was significantly increased by E409Q, but not by A390V compared to WT (0.49±0.14 in WT vs.0.94±0.23 in A390V, p = 0.099; vs. 1.12±0.24 in E409Q, p = 0.019). We demonstrated that a novel SNTA1 variant is likely causative for diLQTS by augmenting INa-L. These data suggest that variants within the NaV1.5-interacting α1-syntrophin are a potential mechanism for diLQTS, thereby expanding the concept that variants within congenital LQTS loci can cause diLQTS.
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Ambrosio G, Tamargo J, Grant PJ. Non-haemodynamic anti-anginal agents in the management of patients with stable coronary artery disease and diabetes: A review of the evidence. Diab Vasc Dis Res 2016; 13:98-112. [PMID: 26873904 DOI: 10.1177/1479164115609028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Patients with coronary artery disease and concomitant diabetes mellitus tend to have more extensive vessel disease than non-diabetes mellitus coronary artery disease patients, are at high risk of adverse cardiovascular events and suffer from a great anginal burden. Very few trials have specifically addressed the issue of optimal anti-anginal therapy in coronary artery disease patients who also have diabetes mellitus. Among 'classical' anti-anginal agents, recent guidelines do not specifically recommend any molecule over others; however, European Society of Cardiology guidelines acknowledge that favourable data in patients with concomitant diabetes mellitus and coronary artery disease are available for trimetazidine and ranolazine, two anti-anginal agents with a non-haemodynamic mechanism of action. The aim of this article is to review available evidence supporting the anti-anginal efficacy of these two drugs in the difficult-to-treat population of diabetes mellitus patients, including their effects on glycated haemoglobin (HbA1c), a measure of medium-term glycaemic control. Although direct head-to-head comparisons have not been performed, available evidence favours ranolazine as an effective anti-anginal agent over trimetazidine in this population. In addition, ranolazine lowers HbA1c, indicating that it may improve glycaemic control in patients with diabetes mellitus. Conversely, scanty data are available on the metabolic effects of trimetazidine in this cohort of patients. Thus, ranolazine may represent a valuable therapeutic option in stable coronary artery disease patients with diabetes mellitus.
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Affiliation(s)
- Giuseppe Ambrosio
- Division of Cardiology, School of Medicine, University of Perugia, Perugia, Italy
| | - Juan Tamargo
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
| | - Peter J Grant
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
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Roden DM. Predicting drug-induced QT prolongation and torsades de pointes. J Physiol 2016; 594:2459-68. [PMID: 26660066 DOI: 10.1113/jp270526] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 12/03/2015] [Indexed: 12/16/2022] Open
Abstract
Drugs used to treat cardiovascular disease as well as those used in the treatment of multiple other conditions can occasionally produce exaggerated prolongation of the QT interval on the electrocardiogram and the morphologically distinctive polymorphic ventricular tachycardia ('torsades de pointes'). This syndrome of drug-induced long QT syndrome has moved from an interesting academic exercise to become a key element in the development of any new drug entity. The prevailing view, which has driven both clinical care and drug regulation, holds that cardiac repolarization represents a balance between inward currents (primarily through calcium and sodium channels) and outward currents (primarily through rapid and slowed delayed rectifier potassium channels) and that block of the rapid delayed rectifier (IKr ) is the primary mechanism whereby drugs prolong individual action potentials, manifest on the surface electrocardiogram as QT interval prolongation. Such marked action potential prolongation in individual cardiac cells, in turn, is accompanied by arrhythmogenic afterdepolarizations thought to trigger torsades de pointes. This review describes the evidence in support of this construct, and describes the way in which clinical and whole heart experiments have informed molecular mechanisms and vice versa. New data that challenge these views and that may, as a result, lead to new clinical care and drug screening paradigms, are discussed.
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Affiliation(s)
- Dan M Roden
- Vanderbilt University, Nashville, TN, 37232, USA
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64
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Page RL, Ghushchyan V, Read RA, Hartsfield CL, Koch BR, Nair KV. Comparative Effectiveness of Ranolazine Versus Traditional Therapies in Chronic Stable Angina Pectoris and Concomitant Diabetes Mellitus and Impact on Health Care Resource Utilization and Cardiac Interventions. Am J Cardiol 2015; 116:1321-8. [PMID: 26358510 DOI: 10.1016/j.amjcard.2015.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/01/2015] [Accepted: 08/01/2015] [Indexed: 11/16/2022]
Abstract
Comparative studies evaluating traditional versus newer antianginal (AA) medications in chronic stable angina pectoris (CSA) on cardiovascular (CV) outcomes and utilization are limited, particularly in patients with diabetes mellitus (DM). Claims data (2008 to 2012) were analyzed using a commercial database. Patients with CSA receiving a β blocker (BB), calcium channel blocker (CCB), long-acting nitrate (LAN), or ranolazine were identified and followed for 12 months after a change in AA therapy. Patients on traditional AA medications were required to have concurrent sublingual nitroglycerin. Therapy change was defined as adding or switching to another traditional AA medication or ranolazine to identify patients whose angina was inadequately controlled with previous therapy. Four groups were identified (BB, CCB, LAN, or ranolazine users) and matched on relevant characteristics. A DM subset was identified. Logistic regression compared revascularization at 30, 60, 90, 180, and 360 days. Negative binomial regression compared all-cause, CV-, and DM-related (in the DM cohort) health care utilization. A total of 8,008 patients were identified with 2,002 patients in each matched group. Majority were men (mean age 66 years). A subset of 3,724 patients with DM (BB, n = 933; CCB, n = 940; LAN, n = 937; and ranolazine, n = 914) resulted from this cohort. Compared to ranolazine in the overall cohort, traditional AA medication exhibited greater odds for revascularization and higher rates in all-cause outpatient, emergency room visits, inpatient length of stay, and CV-related emergency room visits. In the DM cohort, ranolazine demonstrated similar benefits over traditional AA medication. In conclusion, ranolazine use in patients with inadequately controlled chronic angina is associated with less revascularization and all-cause and CV-related health care utilization compared to traditional AA medication.
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Affiliation(s)
- Robert L Page
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy, Aurora, Colorado
| | - Vahram Ghushchyan
- College of Business and Economics, American University of Armenia, Yerevan, Armenia
| | | | | | | | - Kavita V Nair
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy, Aurora, Colorado.
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65
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Cardiovascular pharmacogenomics: current status and future directions. J Hum Genet 2015; 61:79-85. [PMID: 26178435 DOI: 10.1038/jhg.2015.78] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 05/20/2015] [Indexed: 12/29/2022]
Abstract
Drugs are widely used and highly effective in the treatment of heart disease. Nevertheless, in some instances, even drugs effective in a population display lack of efficacy or adverse drug reactions in individual patients, often in an apparently unpredictable fashion. This review summarizes the genomic factors now known to influence variability in responses to widely used cardiovascular drugs such as clopidogrel, warfarin, heparin and statins. Genomic approaches being used to discover new pathways in common cardiovascular diseases and thus potential new targets for drug development are described. Finally, the way in which this new information is likely to be used in an electronic medical record environment is discussed.
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Martinez JM, Wang HZ, Lin RZ, Brink PR, White TW. Differential regulation of Connexin50 and Connexin46 by PI3K signaling. FEBS Lett 2015; 589:1340-5. [PMID: 25935417 PMCID: PMC4433579 DOI: 10.1016/j.febslet.2015.04.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/06/2015] [Accepted: 04/16/2015] [Indexed: 01/28/2023]
Abstract
Gap junction channels can modify their activity in response to cell signaling pathways. Here, we demonstrate that Connexin50 (Cx50) coupling, but not Connexin46 (Cx46), increased when co-expressed with a constitutively active p110α subunit of PI3K in Xenopus oocytes. In addition, inhibition of PI3K signaling by blocking p110α, or Akt, significantly decreased gap junctional conductance in Cx50 transfected HeLa cells, with no effect on Cx46. Alterations in coupling levels were not a result of reduced Cx50 unitary conductance, suggesting that changes in the number of active channels were responsible. These data indicate that Cx50 is specifically regulated by the PI3K signaling pathway.
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Affiliation(s)
- Jennifer M Martinez
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Hong-Zhan Wang
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Richard Z Lin
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Peter R Brink
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Thomas W White
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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67
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Ballou LM, Lin RZ, Cohen IS. Control of cardiac repolarization by phosphoinositide 3-kinase signaling to ion channels. Circ Res 2015; 116:127-37. [PMID: 25552692 DOI: 10.1161/circresaha.116.303975] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Upregulation of phosphoinositide 3-kinase (PI3K) signaling is a common alteration in human cancer, and numerous drugs that target this pathway have been developed for cancer treatment. However, recent studies have implicated inhibition of the PI3K signaling pathway as the cause of a drug-induced long-QT syndrome in which alterations in several ion currents contribute to arrhythmogenic drug activity. Surprisingly, some drugs that were thought to induce long-QT syndrome by direct block of the rapid delayed rectifier (IKr) also seem to inhibit PI3K signaling, an effect that may contribute to their arrhythmogenicity. The importance of PI3K in regulating cardiac repolarization is underscored by evidence that QT interval prolongation in diabetes mellitus also may result from changes in multiple currents because of decreased insulin activation of PI3K in the heart. How PI3K signaling regulates ion channels to control the cardiac action potential is poorly understood. Hence, this review summarizes what is known about the effect of PI3K and its downstream effectors, including Akt, on sodium, potassium, and calcium currents in cardiac myocytes. We also refer to some studies in noncardiac cells that provide insight into potential mechanisms of ion channel regulation by this signaling pathway in the heart. Drug development and safety could be improved with a better understanding of the mechanisms by which PI3K regulates cardiac ion channels and the extent to which PI3K inhibition contributes to arrhythmogenic susceptibility.
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Affiliation(s)
- Lisa M Ballou
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.)
| | - Richard Z Lin
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.).
| | - Ira S Cohen
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.).
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Deletion of PDK1 causes cardiac sodium current reduction in mice. PLoS One 2015; 10:e0122436. [PMID: 25781322 PMCID: PMC4363661 DOI: 10.1371/journal.pone.0122436] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/14/2015] [Indexed: 01/01/2023] Open
Abstract
Background The AGC protein kinase family regulates multiple cellular functions. 3-phosphoinositide-dependent protein kinase-1 (PDK1) is involved in the pathogenesis of arrhythmia, and its downstream factor, Forkhead box O1 (Foxo1), negatively regulates the expression of the cardiac sodium channel, Nav1.5. Mice are known to die suddenly after PDK1 deletion within 11 weeks, but the underlying electrophysiological bases are unclear. Thus, the aim of this study was to investigate the potential mechanisms between PDK1 signaling pathway and cardiac sodium current. Methods and Results Using patch clamp and western blotting techniques, we investigated the role of the PDK1-Foxo1 pathway in PDK1 knockout mice and cultured cardiomyocytes. We found that PDK1 knockout mice undergo slower heart rate, prolonged QRS and QTc intervals and abnormal conduction within the first few weeks of birth. Furthermore, the peak sodium current is decreased by 33% in cells lacking PDK1. The phosphorylation of Akt (308T) and Foxo1 (24T) and the expression of Nav1.5 in the myocardium of PDK1-knockout mice are decreased, while the nuclear localization of Foxo1 is increased. The role of the PDK1-Foxo1 pathway in regulating Nav1.5 levels and sodium current density was verified using selective PDK1, Akt and Foxo1 inhibitors and isolated neonatal rat cardiomyocytes. Conclusion These results indicate that PDK1 participates in the dysregulation of electrophysiological basis by regulating the PDK1-Foxo1 pathway, which in turn regulates the expression of Nav1.5 and cardiac sodium channel function.
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Regulation of the cardiac Na+ channel NaV1.5 by post-translational modifications. J Mol Cell Cardiol 2015; 82:36-47. [PMID: 25748040 DOI: 10.1016/j.yjmcc.2015.02.013] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/28/2015] [Accepted: 02/17/2015] [Indexed: 02/07/2023]
Abstract
The cardiac voltage-gated Na(+) channel, Na(V)1.5, is responsible for the upstroke of the action potential in cardiomyocytes and for efficient propagation of the electrical impulse in the myocardium. Even subtle alterations of Na(V)1.5 function, as caused by mutations in its gene SCN5A, may lead to many different arrhythmic phenotypes in carrier patients. In addition, acquired malfunctions of Na(V)1.5 that are secondary to cardiac disorders such as heart failure and cardiomyopathies, may also play significant roles in arrhythmogenesis. While it is clear that the regulation of Na(V)1.5 protein expression and function tightly depends on genetic mechanisms, recent studies have demonstrated that Na(V)1.5 is the target of various post-translational modifications that are pivotal not only in physiological conditions, but also in disease. In this review, we examine the recent literature demonstrating glycosylation, phosphorylation by Protein Kinases A and C, Ca(2+)/Calmodulin-dependent protein Kinase II, Phosphatidylinositol 3-Kinase, Serum- and Glucocorticoid-inducible Kinases, Fyn and Adenosine Monophosphate-activated Protein Kinase, methylation, acetylation, redox modifications, and ubiquitylation of Na(V)1.5. Modern and sensitive mass spectrometry approaches, applied directly to channel proteins that were purified from native cardiac tissues, have enabled the determination of the precise location of post-translational modification sites, thus providing essential information for understanding the mechanistic details of these regulations. The current challenge is first, to understand the roles of these modifications on the expression and the function of Na(V)1.5, and second, to further identify other chemical modifications. It is postulated that the diversity of phenotypes observed with Na(V)1.5-dependent disorders may partially arise from the complex post-translational modifications of channel protein components.
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Cardiac late Na+ current: Proarrhythmic effects, roles in long QT syndromes, and pathological relationship to CaMKII and oxidative stress. Heart Rhythm 2015; 12:440-8. [DOI: 10.1016/j.hrthm.2014.11.009] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Indexed: 12/16/2022]
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Arnold SV, McGuire DK, Spertus JA, Li Y, Yue P, Ben-Yehuda O, Belardinelli L, Jones PG, Olmsted A, Chaitman BR, Kosiborod M. Effectiveness of ranolazine in patients with type 2 diabetes mellitus and chronic stable angina according to baseline hemoglobin A1c. Am Heart J 2014; 168:457-465.e2. [PMID: 25262254 DOI: 10.1016/j.ahj.2014.06.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 06/02/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND Ranolazine reduces the frequency of angina and use of sublingual nitroglycerin (SL NTG) in stable angina patients with type 2 diabetes (T2DM). Because pre-clinical data suggest that myocardial late sodium current (INaL), the target of ranolazine, is increased by hyperglycemia, we investigated whether the efficacy of ranolazine was influenced by glycemic control. METHODS TERISA was a multinational, randomized, double-blind trial of ranolazine vs. placebo in patients with T2DM and stable angina. Anginal episodes and SL NTG use were recorded daily in an electronic diary. Health status was evaluated at baseline and 8weeks post-randomization using the Seattle Angina Questionnaire (SAQ). The interaction between baseline HbA1c and treatment effect was tested across endpoints using analysis of covariance models, with HbA1c as a continuous variable with restricted cubic splines. RESULTS The study included 913 patients, with mean age 63.6years, 39% women, mean T2DM duration 7.4years, and mean HbA1c of 7.3%. Heterogeneity of efficacy by HbA1c was observed for the primary endpoint of angina frequency (Pinteraction = .027), the key secondary endpoint of SL NTG use (Pinteraction = .030), SAQ angina frequency (Pinteraction = .001), and SAQ treatment satisfaction (Pinteraction = .025) with greater efficacy of ranolazine in those with higher HbA1c values, increasing continuously from HbA1c levels >6.5%. CONCLUSION Among patients with T2DM and stable angina, the therapeutic benefits of ranolazine were greater in those with higher HbA1c values. These data suggest that ranolazine is particularly beneficial in patients with stable angina who have suboptimally controlled T2DM.
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Pereira L, Ruiz-Hurtado G, Rueda A, Mercadier JJ, Benitah JP, Gómez AM. Calcium signaling in diabetic cardiomyocytes. Cell Calcium 2014; 56:372-80. [PMID: 25205537 DOI: 10.1016/j.ceca.2014.08.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 07/24/2014] [Accepted: 08/07/2014] [Indexed: 12/18/2022]
Abstract
Diabetes mellitus is one of the most common medical conditions. It is associated to medical complications in numerous organs and tissues, of which the heart is one of the most important and most prevalent organs affected by this disease. In fact, cardiovascular complications are the most common cause of death among diabetic patients. At the end of the 19th century, the weakness of the heart in diabetes was noted as part of the general muscular weakness that exists in that disease. However, it was only in the eighties that diabetic cardiomyopathy was recognized, which comprises structural and functional abnormalities in the myocardium in diabetic patients even in the absence of coronary artery disease or hypertension. This disorder has been associated with both type 1 and type 2 diabetes, and is characterized by early-onset diastolic dysfunction and late-onset systolic dysfunction, in which alteration in Ca(2+) signaling is of major importance, since it controls not only contraction, but also excitability (and therefore is involved in rhythmic disorder), enzymatic activity, and gene transcription. Here we attempt to give a brief overview of Ca(2+) fluxes alteration reported on diabetes, and provide some new data on differential modulation of Ca(2+) handling alteration in males and females type 2 diabetic mice to promote further research. Due to space limitations, we apologize for those authors whose important work is not cited.
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Affiliation(s)
- Laetitia Pereira
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Gema Ruiz-Hurtado
- Unidad de Hipertensión, Instituto de Investigación i+12, Hospital Universitario 12 de Octubre, Madrid, Spain; Instituto Pluridisciplinar, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Angélica Rueda
- Departamento de Bioquímica, Cinvestav-IPN, México, DF, Mexico
| | - Jean-Jacques Mercadier
- Inserm, UMR S769, Faculté de Pharmacie, Université Paris Sud, Labex LERMIT, DHU TORINO, Châtenay-Malabry, France; Université Paris Diderot - Sorbonne Paris Cité, Assistance Publique - Hôpitaux de Paris (AP-HP), France
| | - Jean-Pierre Benitah
- Inserm, UMR S769, Faculté de Pharmacie, Université Paris Sud, Labex LERMIT, DHU TORINO, Châtenay-Malabry, France
| | - Ana María Gómez
- Inserm, UMR S769, Faculté de Pharmacie, Université Paris Sud, Labex LERMIT, DHU TORINO, Châtenay-Malabry, France.
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