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Isaksen JL, Sivertsen CB, Jensen CZ, Graff C, Linz D, Ellervik C, Jensen MT, Jørgensen PG, Kanters JK. Electrocardiographic markers in patients with type 2 diabetes and the role of diabetes duration. J Electrocardiol 2024; 84:129-136. [PMID: 38663227 DOI: 10.1016/j.jelectrocard.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/01/2024] [Accepted: 04/14/2024] [Indexed: 06/16/2024]
Abstract
BACKGROUND The association between type 2 diabetes and electrocardiographic (ECG) markers are incompletely explored and the dependence on diabetes duration is largely unknown. We aimed to investigate the electrocardiographic (ECG) changes associated with type 2 diabetes over time. METHODS In this cross-sectional study, we matched people with type 2 diabetes 1:1 on sex, age, and body mass index with people without diabetes from the general population. We regressed ECG markers with the presence of diabetes and the duration of clinical diabetes, respectively, adjusted for sex, age, body mass index, smoking, heart rate, diabetes medication, renal function, hypertension, and myocardial infarction. RESULTS We matched 988 people with type 2 diabetes (332, 34% females) with as many controls. Heart rate was 8 bpm higher (p < 0.001) in people with vs. without type 2 diabetes, but the difference declined with increasing diabetes duration. For most depolarization markers, the difference between people with and without type 2 diabetes increased progressively with diabetes duration. On average, R-wave amplitude was 6 mm lower in lead V5 (p < 0.001), P-wave duration was 5 ms shorter (p < 0.001) and QRS duration was 3 ms (p = 0.03). Among repolarization markers, T-wave amplitude (measured in V5) was lower in patients with type 2 diabetes (1 mm lower, p < 0.001) and the QRS-T angle was 10 degrees wider (p = 0.002). We observed no association between diabetes duration and repolarization markers. CONCLUSIONS Type 2 diabetes was independently associated with electrocardiographic depolarization and repolarization changes. Differences in depolarization markers, but not repolarization markers, increased with increasing diabetes duration.
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Affiliation(s)
- Jonas L Isaksen
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Christian B Sivertsen
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian Zinck Jensen
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Claus Graff
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Dominik Linz
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christina Ellervik
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Data and Data Support, Region Zealand, Sorø, Denmark
| | | | - Peter G Jørgensen
- Department of Cardiology, Herlev and Gentofte University Hospital, Copenhagen, Denmark
| | - Jørgen K Kanters
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Center of Physiological Research, University of California San Francisco, San Francisco, USA
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Rupee S, Rupee K, Singh RB, Hanoman C, Ismail AMA, Smail M, Singh J. Diabetes-induced chronic heart failure is due to defects in calcium transporting and regulatory contractile proteins: cellular and molecular evidence. Heart Fail Rev 2022; 28:627-644. [PMID: 36107271 DOI: 10.1007/s10741-022-10271-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/07/2022] [Indexed: 11/04/2022]
Abstract
Heart failure (HF) is a major deteriorating disease of the myocardium due to weak myocardial muscles. As such, the heart is unable to pump blood efficiently around the body to meet its constant demand. HF is a major global health problem with more than 7 million deaths annually worldwide, with some patients dying suddenly due to sudden cardiac death (SCD). There are several risk factors which are associated with HF and SCD which can negatively affect the heart synergistically. One major risk factor is diabetes mellitus (DM) which can cause an elevation in blood glucose level or hyperglycaemia (HG) which, in turn, has an insulting effect on the myocardium. This review attempted to explain the subcellular, cellular and molecular mechanisms and to a lesser extent, the genetic factors associated with the development of diabetes- induced cardiomyopathy due to the HG which can subsequently lead to chronic heart failure (CHF) and SCD. The study first explained the structure and function of the myocardium and then focussed mainly on the excitation-contraction coupling (ECC) processes highlighting the defects of calcium transporting (SERCA, NCX, RyR and connexin) and contractile regulatory (myosin, actin, titin and troponin) proteins. The study also highlighted new therapies and those under development, as well as preventative strategies to either treat or prevent diabetic cardiomyopathy (DCM). It is postulated that prevention is better than cure.
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3
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Metformin Reduces Potassium Currents and Prolongs Repolarization in Non-Diabetic Heart. Int J Mol Sci 2022; 23:ijms23116021. [PMID: 35682699 PMCID: PMC9181026 DOI: 10.3390/ijms23116021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/14/2022] [Accepted: 05/24/2022] [Indexed: 01/27/2023] Open
Abstract
Metformin is the first choice drug for the treatment of type 2 diabetes due to positive results in reducing hyperglycaemia and insulin resistance. However, diabetic patients have higher risk of ventricular arrhythmia and sudden cardiac death, and metformin failed to reduce ventricular arrhythmia in clinical trials. In order to explore the mechanisms responsible for the lack of protective effect, we investigated in vivo the effect of metformin on cardiac electrical activity in non-diabetic rats; and in vitro in isolated ventricular myocytes, HEK293 cells expressing the hERG channel and human induced pluripotent stem cells derived cardiomyocytes (hIPS-CMs). Surface electrocardiograms showed that long-term metformin treatment (7 weeks) at therapeutic doses prolonged cardiac repolarization, reflected as QT and QTc interval duration, and increased ventricular arrhythmia during the caffeine/dobutamine challenge. Patch-clamp recordings in ventricular myocytes isolated from treated animals showed that the cellular mechanism is a reduction in the cardiac transient outward potassium current (Ito). In vitro, incubation with metformin for 24 h also reduced Ito, prolonged action potential duration, and increased spontaneous contractions in ventricular myocytes isolated from control rats. Metformin incubation also reduced IhERG in HEK293 cells. Finally, metformin incubation prolonged action potential duration at 30% and 90% of repolarization in hIPS-CMs, which is compatible with the reduction of Ito and IhERG. Our results show that metformin directly modifies the electrical behavior of the normal heart. The mechanism consists in the inhibition of repolarizing currents and the subsequent decrease in repolarization capacity, which prolongs AP and QTc duration.
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4
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Mittal A, Garg R, Bahl A, Khullar M. Molecular Mechanisms and Epigenetic Regulation in Diabetic Cardiomyopathy. Front Cardiovasc Med 2022; 8:725532. [PMID: 34977165 PMCID: PMC8716459 DOI: 10.3389/fcvm.2021.725532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 11/15/2021] [Indexed: 12/25/2022] Open
Abstract
Diabetes mellitus (DM) is an important lifestyle disease. Type 2 diabetes is one of the prime contributors to cardiovascular diseases (CVD) and diabetic cardiomyopathy (DbCM) and leads to increased morbidity and mortality in patients with DM. DbCM is a typical cardiac disease, characterized by cardiac remodeling in the presence of DM and in the absence of other comorbidities such as hypertension, valvular diseases, and coronary artery disease. DbCM is associated with defective cardiac metabolism, altered mitochondrial structure and function, and other physiological and pathophysiological signaling mechanisms such as oxidative stress, inflammation, myocardial apoptosis, and autophagy. Epigenetic modifiers are crucial players in the pathogenesis of DbCM. Thus, it is important to explore the role of epigenetic modifiers or modifications in regulating molecular pathways associated with DbCM. In this review, we have discussed the role of various epigenetic mechanisms such as histone modifications (acetylation and methylation), DNA methylation and non-coding RNAs in modulating molecular pathways involved in the pathophysiology of the DbCM.
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Affiliation(s)
- Anupam Mittal
- Department of Translational and Regenerative Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rajni Garg
- Council of Scientific and Industrial Research - Institute of Microbial Technology, Chandigarh, India
| | - Ajay Bahl
- Department of Cardiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Madhu Khullar
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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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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Torres-Jacome J, Ortiz-Fuentes BS, Bernabe-Sanchez D, Lopez-Silva B, Velasco M, Ita-Amador ML, Albarado-Ibañez A. Ventricular Dysfunction in Obese and Nonobese Rats with Metabolic Syndrome. J Diabetes Res 2022; 2022:9321445. [PMID: 35242881 PMCID: PMC8888058 DOI: 10.1155/2022/9321445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 11/18/2022] Open
Abstract
Obesity and dyslipidemias are both signs of metabolic syndrome, usually associated with ventricular arrhythmias. Here, we tried to identify cardiac electrical alteration and biomarkers in nonobese rats with metabolic syndrome (MetS), and these findings might lead to more lethal arrhythmias than obese animals. The MetS model was developed in Wistar rats with high-sucrose diet (20%), and after twenty-eight weeks were obtained two subgroups: obese (OMetS) and nonobese (NOMetS). The electrocardiogram was used to measure the ventricular arrhythmias and changes in the heart rate variability. Also, we measured ventricular hypertrophy and its relationship with electrical activity alterations of both ventricles, using micro-electrode and voltage clamp techniques. Also, we observed alterations in the contraction force of ventricles where a transducer was used to record mechanical and electrical papillary muscle, simultaneously. Despite both subgroups presenting long QT syndrome (0.66 ± 0.05 and 0.66 ± 0.07 ms with respect to the control 0.55 ± 0.1 ms), the changes in the heart rate variability were present only in OMetS, while the NOMetS subgroup presented changes in QT interval variability (NOMetS SD = 1.8, SD2 = 2.8; SD1/SD2 = 0.75). Also, the NOMetS revealed tachycardia (10%; p < 0.05) with changes in action potential duration (63% in the right papillary and 50% in the left papillary) in the ventricular papillary which are correlated with certain alterations in the potassium currents and the force of contraction. The OMetS showed an increase in action potential duration and the force of contraction in both ventricles, which are explained as bradycardia. Our results revealed lethal arrhythmias in both MetS subgroups, irrespectively of the presence of obesity. Consequently, the NOMetS showed mechanical-electrical alterations regarding ventricle hypertrophy that should be at the NOMetS, leading to an increase of CV mortality.
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Affiliation(s)
- Julian Torres-Jacome
- Laboratorio de Fisiopatología Cardiovascular, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Brian Sabino Ortiz-Fuentes
- Laboratorio de Fisiopatología Cardiovascular, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Daniela Bernabe-Sanchez
- Laboratorio de Fisiopatología Cardiovascular, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Benjamin Lopez-Silva
- Laboratorio de Fisiopatología Cardiovascular, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Myrian Velasco
- Neuroscience Division, Instituto de Fisiología Celular, Department of Cognitive Neuroscience, Universidad Nacional Autónoma de México, México City, Mexico
| | - Martha Lucia Ita-Amador
- Laboratorio de Fisiopatología Cardiovascular, Complejo Nororiental, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Alondra Albarado-Ibañez
- Laboratorio de Fisiopatología Cardiovascular, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- Laboratorio de Aplicaciones Biotecnológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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7
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Gallego M, Zayas-Arrabal J, Alquiza A, Apellaniz B, Casis O. Electrical Features of the Diabetic Myocardium. Arrhythmic and Cardiovascular Safety Considerations in Diabetes. Front Pharmacol 2021; 12:687256. [PMID: 34305599 PMCID: PMC8295895 DOI: 10.3389/fphar.2021.687256] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/15/2021] [Indexed: 12/20/2022] Open
Abstract
Diabetes is a chronic metabolic disease characterized by hyperglycemia in the absence of treatment. Among the diabetes-associated complications, cardiovascular disease is the major cause of mortality and morbidity in diabetic patients. Diabetes causes a complex myocardial dysfunction, referred as diabetic cardiomyopathy, which even in the absence of other cardiac risk factors results in abnormal diastolic and systolic function. Besides mechanical abnormalities, altered electrical function is another major feature of the diabetic myocardium. Both type 1 and type 2 diabetic patients often show cardiac electrical remodeling, mainly a prolonged ventricular repolarization visible in the electrocardiogram as a lengthening of the QT interval duration. The underlying mechanisms at the cellular level involve alterations on the expression and activity of several cardiac ion channels and their associated regulatory proteins. Consequent changes in sodium, calcium and potassium currents collectively lead to a delay in repolarization that can increase the risk of developing life-threatening ventricular arrhythmias and sudden death. QT duration correlates strongly with the risk of developing torsade de pointes, a form of ventricular tachycardia that can degenerate into ventricular fibrillation. Therefore, QT prolongation is a qualitative marker of proarrhythmic risk, and analysis of ventricular repolarization is therefore required for the approval of new drugs. To that end, the Thorough QT/QTc analysis evaluates QT interval prolongation to assess potential proarrhythmic effects. In addition, since diabetic patients have a higher risk to die from cardiovascular causes than individuals without diabetes, cardiovascular safety of the new antidiabetic drugs must be carefully evaluated in type 2 diabetic patients. These cardiovascular outcome trials reveal that some glucose-lowering drugs actually reduce cardiovascular risk. The mechanism of cardioprotection might involve a reduction of the risk of developing arrhythmia.
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Affiliation(s)
- Mónica Gallego
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Julián Zayas-Arrabal
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Amaia Alquiza
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Beatriz Apellaniz
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Oscar Casis
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
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8
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Zayas-Arrabal J, Alquiza A, Tuncay E, Turan B, Gallego M, Casis O. Molecular and Electrophysiological Role of Diabetes-Associated Circulating Inflammatory Factors in Cardiac Arrhythmia Remodeling in a Metabolic-Induced Model of Type 2 Diabetic Rat. Int J Mol Sci 2021; 22:ijms22136827. [PMID: 34202017 PMCID: PMC8268936 DOI: 10.3390/ijms22136827] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 12/29/2022] Open
Abstract
Background: Diabetic patients have prolonged cardiac repolarization and higher risk of arrhythmia. Besides, diabetes activates the innate immune system, resulting in higher levels of plasmatic cytokines, which are described to prolong ventricular repolarization. Methods: We characterize a metabolic model of type 2 diabetes (T2D) with prolonged cardiac repolarization. Sprague-Dawley rats were fed on a high-fat diet (45% Kcal from fat) for 6 weeks, and a low dose of streptozotozin intraperitoneally injected at week 2. Body weight and fasting blood glucose were measured and electrocardiograms of conscious animals were recorded weekly. Plasmatic lipid profile, insulin, cytokines, and arrhythmia susceptibility were determined at the end of the experimental period. Outward K+ currents and action potentials were recorded in isolated ventricular myocytes by patch-clamp. Results: T2D animals showed insulin resistance, hyperglycemia, and elevated levels of plasma cholesterol, triglycerides, TNFα, and IL-1b. They also developed bradycardia and prolonged QTc-interval duration that resulted in increased susceptibility to severe ventricular tachycardia under cardiac challenge. Action potential duration (APD) was prolonged in control cardiomyocytes incubated 24 h with plasma isolated from diabetic rats. However, adding TNFα and IL-1b receptor blockers to the serum of diabetic animals prevented the increased APD. Conclusions: The elevation of the circulating levels of TNFα and IL-1b are responsible for impaired ventricular repolarization and higher susceptibility to cardiac arrhythmia in our metabolic model of T2D.
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Affiliation(s)
- Julian Zayas-Arrabal
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
| | - Amaia Alquiza
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
| | - Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, 06100 Ankara, Turkey;
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Lokman Hekim University, 06510 Ankara, Turkey;
| | - Monica Gallego
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
| | - Oscar Casis
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
- Correspondence: ; Tel.: +34-945013033
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9
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Ozturk N, Uslu S, Ozdemir S. Diabetes-induced changes in cardiac voltage-gated ion channels. World J Diabetes 2021; 12:1-18. [PMID: 33520105 PMCID: PMC7807254 DOI: 10.4239/wjd.v12.i1.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/05/2020] [Accepted: 11/13/2020] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus affects the heart through various mechanisms such as microvascular defects, metabolic abnormalities, autonomic dysfunction and incompatible immune response. Furthermore, it can also cause functional and structural changes in the myocardium by a disease known as diabetic cardiomyopathy (DCM) in the absence of coronary artery disease. As DCM progresses it causes electrical remodeling of the heart, left ventricular dysfunction and heart failure. Electrophysiological changes in the diabetic heart contribute significantly to the incidence of arrhythmias and sudden cardiac death in diabetes mellitus patients. In recent studies, significant changes in repolarizing K+ currents, Na+ currents and L-type Ca2+ currents along with impaired Ca2+ homeostasis and defective contractile function have been identified in the diabetic heart. In addition, insulin levels and other trophic factors change significantly to maintain the ionic channel expression in diabetic patients. There are many diagnostic tools and management options for DCM, but it is difficult to detect its development and to effectively prevent its progress. In this review, diabetes-associated alterations in voltage-sensitive cardiac ion channels are comprehensively assessed to understand their potential role in the pathophysiology and pathogenesis of DCM.
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Affiliation(s)
- Nihal Ozturk
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Serkan Uslu
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Semir Ozdemir
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
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Yurre ARDE, Martins EGL, Lopez-Alarcon M, Cabral B, Vera N, Lopes JA, Galina A, Takiya CM, Lindoso RS, Vieyra A, SÁenz OC, Medei E. Type 2 diabetes mellitus alters cardiac mitochondrial content and function in a non-obese mice model. AN ACAD BRAS CIENC 2020; 92:e20191340. [PMID: 32813865 DOI: 10.1590/0001-3765202020191340] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 03/06/2020] [Indexed: 11/21/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is associated with an increase of premature appearance of several disorders such as cardiac complications. Thus, we test the hypothesis that a combination of a high fat diet (HFD) and low doses of streptozotocin (STZ) recapitulate a suitable mice model of T2DM to study the cardiac mitochondrial disturbances induced by this disease. Animals were divided in 2 groups: the T2DM group was given a HFD and injected with 2 low doses of STZ, while the CNTRL group was given a standard chow and a buffer solution. The combination of HFD and STZ recapitulate the T2DM metabolic profile showing higher blood glucose levels in T2DM mice when compared to CNTRL, and also, insulin resistance. The kidney structure/function was preserved. Regarding cardiac mitochondrial function, in all phosphorylative states, the cardiac mitochondria from T2DM mice presented reduced oxygen fluxes when compared to CNTRL mice. Also, mitochondria from T2DM mice showed decreased citrate synthase activity and lower protein content of mitochondrial complexes. Our results show that in this non-obese T2DM model, which recapitulates the classical metabolic alterations, mitochondrial function is impaired and provides a useful model to deepen study the mechanisms underlying these alterations.
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Affiliation(s)
- Ainhoa R DE Yurre
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Eduarda G L Martins
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Micaela Lopez-Alarcon
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Bruno Cabral
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Narendra Vera
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Jarlene A Lopes
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Antonio Galina
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Christina M Takiya
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Rafael S Lindoso
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Adalberto Vieyra
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Oscar C SÁenz
- Faculdade de Farmacia, Universidade do País Vasco (UPV-EHU), Vitoria-Gasteiz, Spain
| | - Emiliano Medei
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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11
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Lozano WM, Parra G, Arias-Mutis OJ, Zarzoso M. Exercise Training Protocols in Rabbits Applied in Cardiovascular Research. Animals (Basel) 2020; 10:ani10081263. [PMID: 32722314 PMCID: PMC7459864 DOI: 10.3390/ani10081263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 11/20/2022] Open
Abstract
Simple Summary Several animal models have been used to understand the physiological adaptations produced by exercise training in the healthy and diseased cardiovascular system. Among those, the protocols for acute and chronic exercise in rabbits present several advantages compared to other large animal models. In addition, the rabbit model has important physiological similarities with humans. On the other hand, the design of the training protocol is a key factor to induce the physiological adaptations. Here, we review the different training protocols used in rabbits and the different physiological adaptations produced in the cardiovascular system, in normal and pathological conditions. Abstract Rabbit exercise protocols allow for the evaluation of physiological and biomechanical changes and responses to episodes of acute or chronic exercise. The observed physiological changes are normal responses to stress, that is, adaptive responses to maintain or restore homeostasis after acute exercise. Indeed, the rabbit model is advantageous since (a) it has important physiological similarities in terms of the functioning of multiple organ systems, and can quickly induce alterations in pathophysiological conditions that resemble those of humans, and (b) it allows the implementation of a low-cost model in comparison with other large animals. When designing an exercise training protocol for rabbits, it is important to consider variables such as race, gender, age and, especially, training parameters such as volume, intensity, or rest, among others, to determine the outcome of the research. Therefore, the objective of this review is to identify and analyze exercise training protocols in rabbits in different experimental applications and the various physiological adaptations that are presented, with special focus in cardiovascular adaptations.
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Affiliation(s)
- Wilson M. Lozano
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (W.M.L.); (G.P.); (O.J.A.-M.)
| | - Germán Parra
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (W.M.L.); (G.P.); (O.J.A.-M.)
- INCLIVA, Instituto de Investigación Sanitaria, 46010 Valencia, Spain
| | - Oscar J. Arias-Mutis
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (W.M.L.); (G.P.); (O.J.A.-M.)
- INCLIVA, Instituto de Investigación Sanitaria, 46010 Valencia, Spain
- CIBERCV, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Manuel Zarzoso
- Department of Physiotherapy, Universitat de València, 46010 Valencia, Spain
- Correspondence: ; Tel.: +34-963-983-853
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12
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Bacevic M, Rompen E, Radermecker R, Drion P, Lambert F. Practical considerations for reducing mortality rates in alloxan-induced diabetic rabbits. Heliyon 2020; 6:e04103. [PMID: 32577551 PMCID: PMC7305394 DOI: 10.1016/j.heliyon.2020.e04103] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 05/12/2020] [Accepted: 05/27/2020] [Indexed: 02/07/2023] Open
Abstract
Chemically-induced diabetic animal models have been employed in many areas of diabetes mellitus (DM) research, but managing post-induction animal survival rates remains one of the main downsides. The aim of the present study was to propose a reliable approach to animal management and monitoring after DM induction in a rabbit model in order to reduce animal mortality rates. DM was induced by injecting alloxan in 12 New Zealand White rabbits. A preventive subcutaneous glucose administration to counteract a potentially lethal hypoglycemic phase following alloxan injection was performed on individual bases. Blood glucose level (BGL) was checked hourly for the first 36 h, then every 2 h until the hyperglycemic state was confirmed. All 12 rabbits survived a 48-hour post-induction phase. The critical hypoglycemic phase's start points and duration differed significantly among the rabbits, lasting from 6.7 to 37 h (19.75 ± 8.44). The rabbits entered the final hyperglycemic phase 18 h at the earliest and 42 h at the latest after induction (26.63 ± 7.07). The average daily BGLs throughout the study period ranged from 268 to 512 mg/dL (413.73 ± 76.69). Eleven rabbits survived until the end of the experiment. The variability of rabbits' responses to alloxan injection emphasizes the importance of monitoring rabbit behavior and thoroughly checking BGLs, followed by a preventive glucose administration based on rabbits' individual needs for up to 36 h after alloxan injection. The proposed approach seems to reduce animal mortality.
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Affiliation(s)
- Miljana Bacevic
- Dental Biomaterials Research Unit (d-BRU), Faculty of Medicine, University of Liege, Liege, Belgium
| | - Eric Rompen
- Department of Periodontology and Oral Surgery, Faculty of Medicine, University of Liege, Liege, Belgium
| | - Regis Radermecker
- Clinical Pharmacology, University of Liege, Liege, Belgium.,Department of Diabetes, Nutrition and Metabolic Disorders, CHU Liege, Liege, Belgium
| | - Pierre Drion
- Experimental Surgery Unit, GIGA & Credec, University of Liege, Liege, Belgium
| | - France Lambert
- Dental Biomaterials Research Unit (d-BRU), Faculty of Medicine, University of Liege, Liege, Belgium.,Department of Periodontology and Oral Surgery, Faculty of Medicine, University of Liege, Liege, Belgium
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Russell J, Du Toit EF, Peart JN, Patel HH, Headrick JP. Myocyte membrane and microdomain modifications in diabetes: determinants of ischemic tolerance and cardioprotection. Cardiovasc Diabetol 2017; 16:155. [PMID: 29202762 PMCID: PMC5716308 DOI: 10.1186/s12933-017-0638-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/22/2017] [Indexed: 02/06/2023] Open
Abstract
Cardiovascular disease, predominantly ischemic heart disease (IHD), is the leading cause of death in diabetes mellitus (DM). In addition to eliciting cardiomyopathy, DM induces a ‘wicked triumvirate’: (i) increasing the risk and incidence of IHD and myocardial ischemia; (ii) decreasing myocardial tolerance to ischemia–reperfusion (I–R) injury; and (iii) inhibiting or eliminating responses to cardioprotective stimuli. Changes in ischemic tolerance and cardioprotective signaling may contribute to substantially higher mortality and morbidity following ischemic insult in DM patients. Among the diverse mechanisms implicated in diabetic impairment of ischemic tolerance and cardioprotection, changes in sarcolemmal makeup may play an overarching role and are considered in detail in the current review. Observations predominantly in animal models reveal DM-dependent changes in membrane lipid composition (cholesterol and triglyceride accumulation, fatty acid saturation vs. reduced desaturation, phospholipid remodeling) that contribute to modulation of caveolar domains, gap junctions and T-tubules. These modifications influence sarcolemmal biophysical properties, receptor and phospholipid signaling, ion channel and transporter functions, contributing to contractile and electrophysiological dysfunction, cardiomyopathy, ischemic intolerance and suppression of protective signaling. A better understanding of these sarcolemmal abnormalities in types I and II DM (T1DM, T2DM) can inform approaches to limiting cardiomyopathy, associated IHD and their consequences. Key knowledge gaps include details of sarcolemmal changes in models of T2DM, temporal patterns of lipid, microdomain and T-tubule changes during disease development, and the precise impacts of these diverse sarcolemmal modifications. Importantly, exercise, dietary, pharmacological and gene approaches have potential for improving sarcolemmal makeup, and thus myocyte function and stress-resistance in this ubiquitous metabolic disorder.
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Affiliation(s)
- Jake Russell
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Eugene F Du Toit
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Jason N Peart
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Hemal H Patel
- VA San Diego Healthcare System and Department of Anesthesiology, University of California San Diego, San Diego, USA
| | - John P Headrick
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia. .,School of Medical Science, Griffith University, Southport, QLD, 4217, Australia.
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14
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José VSDS, Monnerat G, Guerra B, Paredes BD, Kasai-Brunswick TH, de Carvalho ACC, Medei E. Bone-Marrow-Derived Mesenchymal Stromal Cells (MSC) from Diabetic and Nondiabetic Rats Have Similar Therapeutic Potentials. Arq Bras Cardiol 2017; 109:579-589. [PMID: 29364350 PMCID: PMC5783439 DOI: 10.5935/abc.20170176] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/28/2017] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Diabetes mellitus is a severe chronic disease leading to systemic complications, including cardiovascular dysfunction. Previous cell therapy studies have obtained promising results with the use bone marrow mesenchymal stromal cells derived from healthy animals (MSCc) in diabetes animal models. However, the ability of MSC derived from diabetic rats to improve functional cardiac parameters is still unknown. OBJECTIVES To investigate whether bone-marrow-derived MSC from diabetic rats (MSCd) would contribute to recover metabolic and cardiac electrical properties in other diabetic rats. METHODS Diabetes was induced in Wistar rats with streptozotocin. MSCs were characterized by flow cytometry, morphological analysis, and immunohistochemistry. Cardiac electrical function was analyzed using recordings of ventricular action potential. Differences between variables were considered significant when p < 0.05. RESULTS In vitro properties of MSCc and MSCd were evaluated. Both cell types presented similar morphology, growth kinetics, and mesenchymal profile, and could differentiate into adipogenic and osteogenic lineages. However, in an assay for fibroblast colony-forming units (CFU-F), MSCd formed more colonies than MSCc when cultured in expansion medium with or without hydrocortisone (1 µM). In order to compare the therapeutic potential of the cells, the animals were divided into four experimental groups: nondiabetic (CTRL), diabetic (DM), diabetic treated with MSCc (DM + MSCc), and diabetic treated with MSCd (DM + MSCd). The treated groups received a single injection of MSC 4 weeks after the development of diabetes. MSCc and MSCd controlled hyperglycemia and body weight loss and improved cardiac electrical remodeling in diabetic rats. CONCLUSIONS MSCd and MSCc have similar in vitro properties and therapeutic potential in a rat model of diabetes induced with streptozotocin.
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Affiliation(s)
| | - Gustavo Monnerat
- Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ -
Brazil
- Mailing Address: Gustavo Monnerat, Av. Carlos Chagas
Filho, CCS, Bloco G sala G2-45. Postal Code 21941-590, 21941-590, Cidade
Universitária, Rio de Janeiro, RJ - Brazil.
,
| | - Barbara Guerra
- Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ -
Brazil
| | - Bruno Dias Paredes
- Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ -
Brazil
| | | | | | - Emiliano Medei
- Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ -
Brazil
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15
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Kanae H, Hamaguchi S, Wakasugi Y, Kusakabe T, Kato K, Namekata I, Tanaka H. Pathological prolongation of action potential duration as a cause of the reduced alpha-adrenoceptor-mediated negative inotropy in streptozotocin-induced diabetic mice myocardium. J Pharmacol Sci 2017; 135:131-133. [DOI: 10.1016/j.jphs.2017.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/09/2017] [Accepted: 10/12/2017] [Indexed: 10/18/2022] Open
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Dubó S, Gallegos D, Cabrera L, Sobrevia L, Zúñiga L, González M. Cardiovascular Action of Insulin in Health and Disease: Endothelial L-Arginine Transport and Cardiac Voltage-Dependent Potassium Channels. Front Physiol 2016; 7:74. [PMID: 27014078 PMCID: PMC4791397 DOI: 10.3389/fphys.2016.00074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/15/2016] [Indexed: 12/19/2022] Open
Abstract
Impairment of insulin signaling on diabetes mellitus has been related to cardiovascular dysfunction, heart failure, and sudden death. In human endothelium, cationic amino acid transporter 1 (hCAT-1) is related to the synthesis of nitric oxide (NO) and insulin has a vascular effect in endothelial cells through a signaling pathway that involves increases in hCAT-1 expression and L-arginine transport. This mechanism is disrupted in diabetes, a phenomenon potentiated by excessive accumulation of reactive oxygen species (ROS), which contribute to lower availability of NO and endothelial dysfunction. On the other hand, electrical remodeling in cardiomyocytes is considered a key factor in heart failure progression associated to diabetes mellitus. This generates a challenge to understand the specific role of insulin and the pathways involved in cardiac function. Studies on isolated mammalian cardiomyocytes have shown prolongated action potential in ventricular repolarization phase that produces a long QT interval, which is well explained by attenuation in the repolarizing potassium currents in cardiac ventricles. Impaired insulin signaling causes specific changes in these currents, such a decrease amplitude of the transient outward K(+) (Ito) and the ultra-rapid delayed rectifier (IKur) currents where, together, a reduction of mRNA and protein expression levels of α-subunits (Ito, fast; Kv 4.2 and IKs; Kv 1.5) or β-subunits (KChIP2 and MiRP) of K(+) channels involved in these currents in a MAPK mediated pathway process have been described. These results support the hypothesis that lack of insulin signaling can produce an abnormal repolarization in cardiomyocytes. Furthermore, the arrhythmogenic potential due to reduced Ito current can contribute to an increase in the incidence of sudden death in heart failure. This review aims to show, based on pathophysiological models, the regulatory function that would have insulin in vascular system and in cardiac electrophysiology.
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Affiliation(s)
- Sebastián Dubó
- Department of Kinesiology, Faculty of Medicine, Universidad de Concepción Concepción, Chile
| | - David Gallegos
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Lissette Cabrera
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Department of Morphophysiology, Faculty of Medicine, Universidad Diego PortalesSantiago, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de ChileSantiago, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de SevillaSeville, Spain; Faculty of Medicine and Biomedical Sciences, University of Queensland Centre for Clinical Research (UQCCR), University of QueenslandHerston, QLD, Queensland, Australia
| | - Leandro Zúñiga
- Centro de Investigaciones Médicas, Escuela de Medicina, Universidad de Talca Talca, Chile
| | - Marcelo González
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Group of Research and Innovation in Vascular Health (GRIVAS-Health)Chillán, Chile
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Zhang HM, Wang X, Wu ZH, Liu HL, Chen W, Zhang ZZ, Chen D, Zeng TS. Beneficial effect of farnesoid X receptor activation on metabolism in a diabetic rat model. Mol Med Rep 2016; 13:2135-42. [PMID: 26782298 DOI: 10.3892/mmr.2016.4761] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 11/17/2015] [Indexed: 11/06/2022] Open
Abstract
Farnesoid X receptor (FXR) is an important regulator of glucose and lipid homeostasis. However, the exact role of FXR in diabetes remains to be fully elucidated. The present study examined the effects of chenodeoxycholic acid (CDCA), an agonist of FXR, on metabolism profile in a rat model of type 2 diabetes mellitus (T2DM). Male Wistar rats (8‑week‑old; n=40) were randomized into the following four groups (n=10): Untreated control, CDCA‑treated, T2DM, and CDCA‑treated T2DM. To establish the T2DM model, the rats were fed a high‑fat diet (HFD) for 4 weeks and received a single low‑dose intraperitoneal injection of streptozotocin (30 mg/kg), followed by an additional 4 weeks of HFD feeding. CDCA was administrated (10 mg/kg/d) intraperitoneally for 10 days. Reverse transcription‑quantitative polymerase chain reaction and western blotting assays were performed to determine the RNA and protein expression of FXR, phosphoenolpyruvate carboxykinase, G6Pase, proliferator‑activated receptor‑γ coactivator‑1 and short heterodimer partner in rat liver tissue. The results revealed that FXR activation by CDCA did not reduce body weight, but it lowered the plasma levels of fasting glucose, insulin and triglycerides in the T2DM rats. CDCA administration reversed the downregulation of the mRNA and protein expression of FXR in the T2DM rat liver tissue samples. Furthermore, treatment with CDCA reduced the mRNA and protein expression levels of phosphoenolpyruvate carboxykinase, glucose 6‑phosphatase and peroxisome proliferator‑activated receptor‑γ coactivator‑1 in the liver tissue samples of the T2DM rats. By contrast, CDCA treatment increased the mRNA and protein expression levels of short heterodimer partner in the liver tissue samples of the T2DM rats. In conclusion, FXR agonist treatment induces beneficial effects on metabolism in the rat T2DM model. In conclusion, the present study indicated that the FXR agonist may be useful for the treatment of T2DM and hypertriglyceridemia.
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Affiliation(s)
- Hong-Mei Zhang
- Department of Endocrinology, Hubei Integrated Traditional Chinese and Western Medicine Hospital, Wuhan, Hubei 430015, P.R. China
| | - Xuan Wang
- Department of Clinical Teaching and Research, College of Health Science and Nursing, Wuhan Polytechnic University, Wuhan, Hubei 430015, P.R. China
| | - Zhao-Hong Wu
- Department of Endocrinology, Hubei Integrated Traditional Chinese and Western Medicine Hospital, Wuhan, Hubei 430015, P.R. China
| | - Hui-Ling Liu
- Department of Endocrinology, Hubei Integrated Traditional Chinese and Western Medicine Hospital, Wuhan, Hubei 430015, P.R. China
| | - Wei Chen
- Department of Endocrinology, Hubei Integrated Traditional Chinese and Western Medicine Hospital, Wuhan, Hubei 430015, P.R. China
| | - Zhong-Zhi Zhang
- Department of Endocrinology, Hubei Integrated Traditional Chinese and Western Medicine Hospital, Wuhan, Hubei 430015, P.R. China
| | - Dan Chen
- Department of Endocrinology, Hubei Integrated Traditional Chinese and Western Medicine Hospital, Wuhan, Hubei 430015, P.R. China
| | - Tian-Shu Zeng
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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18
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Arroyo-Carmona RE, López-Serrano AL, Albarado-Ibañez A, Mendoza-Lucero FMF, Medel-Cajica D, López-Mayorga RM, Torres-Jácome J. Heart Rate Variability as Early Biomarker for the Evaluation of Diabetes Mellitus Progress. J Diabetes Res 2016; 2016:8483537. [PMID: 27191000 PMCID: PMC4848735 DOI: 10.1155/2016/8483537] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/11/2016] [Accepted: 03/16/2016] [Indexed: 12/13/2022] Open
Abstract
According to the American Diabetes Association (ADA), the side effects of diabetes mellitus have recently increased the global health expenditure each year. Of these, the early diagnostic can contribute to the decrease on renal, cardiovascular, and nervous systems complications. However, the diagnostic criteria, which are commonly used, do not suggest the diabetes progress in the patient. In this study, the streptozotocin model in mice (cDM) was used as early diagnostic criterion to reduce the side effects related to the illness. The results showed some clinical signs similarly to five-year diabetes progress without renal injury, neuropathies, and cardiac neuropathy autonomic in the cDM-model. On the other hand, the electrocardiogram was used to determine alterations in heart rate and heart rate variability (HRV), using the Poincaré plot to quantify the HRV decrease in the cDM-model. Additionally, the SD1/SD2 ratio and ventricular arrhythmias showed increase without side effects of diabetes. Therefore, the use of HRV as an early biomarker contributes to evaluating diabetes mellitus complications from the diagnostic.
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Affiliation(s)
- Rosa Elena Arroyo-Carmona
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, Colonia Casco de Santo Tomas, Delegación Miguel Hidalgo, 11340 Ciudad de México, DF, Mexico
| | - Ana Laura López-Serrano
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, 14 Sur 6301, Colonia Jardines de San Manuel, 72570 Puebla, PUE, Mexico
| | - Alondra Albarado-Ibañez
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, 14 Sur 6301, Colonia Jardines de San Manuel, 72570 Puebla, PUE, Mexico
- Centro de las Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Circuito Mario de la Cueva 20, Insurgentes Sur, Delegación Coyoacán, 04510 Ciudad de México, DF, Mexico
| | | | - David Medel-Cajica
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, 14 Sur 6301, Colonia Jardines de San Manuel, 72570 Puebla, PUE, Mexico
| | - Ruth Mery López-Mayorga
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, Colonia Casco de Santo Tomas, Delegación Miguel Hidalgo, 11340 Ciudad de México, DF, Mexico
| | - Julián Torres-Jácome
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, 14 Sur 6301, Colonia Jardines de San Manuel, 72570 Puebla, PUE, Mexico
- *Julián Torres-Jácome:
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19
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Persson PB. Insulin. Acta Physiol (Oxf) 2015; 214:427-9. [PMID: 26100001 DOI: 10.1111/apha.12543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- P B Persson
- Institute of Vegetative Physiology, Charité-Universitaetsmedizin Berlin, Berlin, Germany.
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20
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Axelsen LN, Calloe K, Braunstein TH, Riemann M, Hofgaard JP, Liang B, Jensen CF, Olsen KB, Bartels ED, Baandrup U, Jespersen T, Nielsen LB, Holstein-Rathlou NH, Nielsen MS. Diet-induced pre-diabetes slows cardiac conductance and promotes arrhythmogenesis. Cardiovasc Diabetol 2015; 14:87. [PMID: 26169175 PMCID: PMC4504126 DOI: 10.1186/s12933-015-0246-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 06/11/2015] [Indexed: 12/17/2022] Open
Abstract
Background Type 2 diabetes is associated with abnormal electrical conduction and sudden cardiac death, but the pathogenic mechanism remains unknown. This study describes electrophysiological alterations in a diet-induced pre-diabetic rat model and examines the underlying mechanism. Methods Sprague–Dawley rats were fed either high-fat diet and fructose water or normal chow and water for 6 weeks. The electrophysiological properties of the whole heart was analyzed by in vivo surface ECG recordings, as wells as ex vivo in Langendorff perfused hearts during baseline, ischemia and re-perfussion. Conduction velocity was examined in isolated tissue strips. Ion channel and gap junction conductances were analyzed by patch-clamp studies in isolated cardiomyocytes. Fibrosis was examined by Masson’s Trichrome staining and thin-layer chromatography was used to analyze cardiac lipid content. Connexin43 (Cx43) expression and distribution was examined by western blotting and immunofluorescence respectively. Results Following 6 weeks of feeding, fructose-fat fed rats (FFFRs) showed QRS prolongation compared to controls (16.1 ± 0.51 (n = 6) vs. 14.7 ± 0.32 ms (n = 4), p < 0.05). Conduction velocity was slowed in FFFRs vs. controls (0.62 ± 0.02 (n = 13) vs. 0.79 ± 0.06 m/s (n = 11), p < 0.05) and Langendorff perfused FFFR hearts were more prone to ventricular fibrillation during reperfusion following ischemia (p < 0.05). The patch-clamp studies revealed no changes in Na+ or K+ currents, cell capacitance or gap junctional coupling. Cx43 expression was also unaltered in FFFRs, but immunofluorescence demonstrated an increased fraction of Cx43 localized at the intercalated discs in FFFRs compared to controls (78 ± 3.3 (n = 5) vs. 60 ± 4.2 % (n = 6), p < 0.01). No fibrosis was detected but FFFRs showed a significant increase in cardiac triglyceride content (1.93 ± 0.19 (n = 12) vs. 0.77 ± 0.13 nmol/mg (n = 12), p < 0.0001). Conclusion Six weeks on a high fructose-fat diet cause electrophysiological changes, which leads to QRS prolongation, decreased conduction velocity and increased arrhythmogenesis during reperfusion. These alterations are not explained by altered gap junctional coupling, Na+, or K+ currents, differences in cell size or fibrosis.
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Affiliation(s)
- Lene Nygaard Axelsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark.
| | - Kirstine Calloe
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Hartig Braunstein
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Core Facility for Integrated Microscopy, University of Copenhagen, Copenhagen, Denmark
| | - Mads Riemann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark
| | - Johannes Pauli Hofgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark
| | - Bo Liang
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark
| | - Christa Funch Jensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark
| | - Kristine Boisen Olsen
- Department of Forensic Medicine, Section of Forensic Pathology, University of Copenhagen, Copenhagen, Denmark
| | - Emil D Bartels
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Ulrik Baandrup
- Centre for Clinical Research, Vendsyssel Hospital/Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark
| | - Lars Bo Nielsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark.,Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Niels-Henrik Holstein-Rathlou
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark
| | - Morten Schak Nielsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Blegdamsvej 3B, Copenhagen, N DK-2200, Denmark
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21
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Figueira MF, Monnerat-Cahli G, Medei E, Carvalho AB, Morales MM, Lamas ME, da Fonseca RN, Souza-Menezes J. MicroRNAs: potential therapeutic targets in diabetic complications of the cardiovascular and renal systems. Acta Physiol (Oxf) 2014; 211:491-500. [PMID: 24837225 DOI: 10.1111/apha.12316] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 02/27/2014] [Accepted: 05/12/2014] [Indexed: 12/28/2022]
Abstract
Diabetes mellitus is a serious health problem that can lead to several pathological complications in numerous organs and tissues. The most important and most prevalent organs affected by this disease are the heart and the kidneys, and these complications are the major causes of death in patients with diabetes. MicroRNAs (miRNAs), short non-coding RNAs, have been found to be functionally important in the regulation of several pathological processes, and they are emerging as an important therapeutic tool to avoid the complications of diabetes mellitus. This review summarizes the knowledge on the effects of miRNAs in diabetes. The use of miRNAs in diabetes from a clinical perspective is also discussed, focusing on their potential role to repair cardiovascular and renal complications.
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Affiliation(s)
- M. F. Figueira
- Centro de Ciências da Saúde; Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
- Laboratório Integrado de Ciências Morfofuncionais; Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Macaé Brazil
| | - G. Monnerat-Cahli
- Centro de Ciências da Saúde; Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
| | - E. Medei
- Centro de Ciências da Saúde; Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
| | - A. B. Carvalho
- Centro de Ciências da Saúde; Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
| | - M. M. Morales
- Centro de Ciências da Saúde; Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
| | - M. E. Lamas
- Centro de Ciências da Saúde; Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
| | - R. N. da Fonseca
- Laboratório Integrado de Ciências Morfofuncionais; Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Macaé Brazil
| | - J. Souza-Menezes
- Centro de Ciências da Saúde; Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro Brazil
- Laboratório Integrado de Ciências Morfofuncionais; Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Macaé Brazil
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22
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Zarzoso M, Mironov S, Guerrero-Serna G, Willis BC, Pandit SV. Ventricular remodelling in rabbits with sustained high-fat diet. Acta Physiol (Oxf) 2014; 211:36-47. [PMID: 24304486 DOI: 10.1111/apha.12185] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/02/2013] [Accepted: 10/19/2013] [Indexed: 12/23/2022]
Abstract
AIM Excess weight gain and obesity are one of the most serious health problems in the western societies. These conditions enhance risk of cardiac disease and have been linked with increased prevalence for cardiac arrhythmias and sudden death. Our goal was to study the ventricular remodelling occurring in rabbits fed with high-fat diet (HFD) and its potential arrhythmogenic mechanisms. METHODS We used 15 NZW rabbits that were randomly assigned to a control (n = 7) or HFD group (n = 8) for 18 weeks. In vivo studies included blood glucose, electrocardiographic, and echocardiographic measurements. Optical mapping was performed in Langendorff-perfused isolated hearts. RESULTS Body weight (3.69 ± 0.31 vs. 2.94 ± 0.18 kg, P < 0.001) and blood glucose levels (230 ± 61 vs. 141 ± 14 mg dL(-1) , P < 0.05) were higher in the HFD group vs. controls. The rate-corrected QT interval and its dispersion were increased in HFD rabbits vs. controls (169 ± 10 vs. 146 ± 13 ms and 37 ± 11 vs. 9 ± 2 ms, respectively; P < 0.05). Echocardiographic analysis showed morphological and functional alterations in HFD rabbits indicative of left ventricle (LV) hypertrophy. Isolated heart studies revealed no changes in repolarization and propagation properties under conditions of normal extracellular K(+) , suggesting that extrinsic factors could underlie those electrocardiographic modifications. There were no differences in the dynamics of ventricular fibrillation (frequency, wave breaks) in the presence of isoproterenol. However, HFD rabbits showed a small reduction in action potential duration and an increased incidence of arrhythmias during hyperkalaemia. CONCLUSION High-fat feeding during 18 weeks in rabbits induced a type II diabetes phenotype, LV hypertrophy, abnormalities in repolarization and susceptibility to arrhythmias during hyperkalaemia.
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Affiliation(s)
- M. Zarzoso
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
- Department of Physiotherapy; Universitat de València; Valencia Spain
| | - S. Mironov
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
| | - G. Guerrero-Serna
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
| | - B. Cicero Willis
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
| | - S. V. Pandit
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
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23
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Monnerat-Cahli G, Trentin-Sonoda M, Guerra B, Manso G, Ferreira ACF, Silva DLSG, Coutinho DC, Carneiro-Ramos MS, Rodrigues DC, Cabral-da-Silva MC, Goldenberg RCS, Nascimento JHM, Campos de Carvalho AC, Medei E. Bone marrow mesenchymal stromal cells rescue cardiac function in streptozotocin-induced diabetic rats. Int J Cardiol 2014; 171:199-208. [PMID: 24374203 DOI: 10.1016/j.ijcard.2013.12.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 11/05/2013] [Accepted: 12/10/2013] [Indexed: 02/06/2023]
Abstract
OBJECTIVES In the present study, we investigated whether MSC-transplantation can revert cardiac dysfunction in streptozotocin-induced diabetic rats and the immunoregulatory effects of MSC were examined. BACKGROUND Cardiac complications are one of the main causes of death in diabetes. Several studies have shown anti-diabetic effects of bone marrow mesenchymal stromal cells (MSC). METHODS/RESULTS The rats were divided in three groups: Non-diabetic, Diabetic and Diabetic-Treated with 5 × 10(6) MSC 4 weeks after establishment of diabetes. Four weeks after MSC-therapy, systemic metabolic parameters, immunological profile and cardiac function were assessed. MSC-transplantation was able to revert the hyperglycemia and body weight loss of the animals. In addition, after MSC-transplantation a decrease in corticosterone and IFN-γ sera levels without restoration of insulin and leptin plasma levels was observed. Also, MSC-therapy improved electrical remodeling, shortening QT and QTc in the ECG and action potential duration of left ventricular myocytes. No arrhythmic events were observed after MSC-transplantation. MSC-therapy rescued the cardiac beta-adrenergic sensitivity by increasing beta-1 adrenergic receptor expression. Both alpha and beta cardiac AMPK and p-AMPK returned to baseline values after MSC-therapy. However, total ERK1 and p-ERK1/2 were not different among groups. CONCLUSION The results indicate that MSC-therapy was able to rescue cardiac impairment induced by diabetes, normalize cardiac AMPK subunit expression and activity, decrease corticosterone and glycemia and exert systemic immunoregulation.
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Affiliation(s)
- Gustavo Monnerat-Cahli
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Mayra Trentin-Sonoda
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo Andre, Brasil
| | - Bárbara Guerra
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Gabriel Manso
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Andrea C F Ferreira
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Diorney L S G Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Danielle C Coutinho
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brasil
| | - Marcela S Carneiro-Ramos
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brasil
| | - Deivid C Rodrigues
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Mauricio C Cabral-da-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Regina C S Goldenberg
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - José H M Nascimento
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Antonio C Campos de Carvalho
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Instituto Nacional de Cardiologia, Rio de Janeiro, Brasil
| | - Emiliano Medei
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil.
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24
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Lopez-Izquierdo A, Pereira RO, Wende AR, Punske BB, Abel ED, Tristani-Firouzi M. The absence of insulin signaling in the heart induces changes in potassium channel expression and ventricular repolarization. Am J Physiol Heart Circ Physiol 2013; 306:H747-54. [PMID: 24375641 DOI: 10.1152/ajpheart.00849.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Diabetes mellitus increases the risk for cardiac dysfunction, heart failure, and sudden death. The wide array of neurohumoral changes associated with diabetes pose a challenge to understanding the roles of specific pathways that alter cardiac function. Here, we use a mouse model with cardiomyocyte-restricted deletion of insulin receptors (CIRKO, cardiac-specific insulin receptor knockout) to study the specific effects of impaired cardiac insulin signaling on ventricular repolarization, independent of the generalized metabolic derangements associated with diabetes. Impaired insulin action caused a reduction in mRNA and protein expression of several key K(+) channels that dominate ventricular repolarization. Specifically, components of transient outward K(+) current fast component (Ito,fast; Kv4.2 and KChiP2) were reduced, consistent with a reduction in the amplitude of Ito,fast in isolated left ventricular CIRKO myocytes, compared with littermate controls. The reduction in Ito,fast resulted in ventricular action potential prolongation and prolongation of the QT interval on the surface ECG. These results support the notion that the lack of insulin signaling in the heart is sufficient to cause the repolarization abnormalities described in other animal models of diabetes.
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Affiliation(s)
- Angelica Lopez-Izquierdo
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
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