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Kang KW, Ko JY, Lee H, Shin SY, Lee WS, Hong J, Kim SW, Lee SK, Oak MH. Surgically Metabolic Resection of Pericardial Fat to Ameliorate Myocardial Mitochondrial Dysfunction in Acute Myocardial Infarction Obese Rats. J Korean Med Sci 2022; 37:e55. [PMID: 35257523 PMCID: PMC8901878 DOI: 10.3346/jkms.2022.37.e55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 01/24/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Pericardial fat (PF) is highly associated with cardiovascular disease but the effectiveness of surgical resection of PF is still unknown for myocardial mitochondrial structure and function in acute myocardial infarction (AMI) with obesity. The aim of this study was to demonstrate the difference in myocardial mitochondrial structure and function between obese AMI with additionally resected PF and those without resected PF. METHODS Obese rats with 12-week high fat diet (45 kcal% fat, n = 21) were randomly assigned into 3 groups: obese control, obese AMI and obese AMI with additionally resected PF. One week after developing AMI and additional resection of PF, echocardiogram, myocardial mitochondrial histomorphology, oxidative phosphorylation system (OXPHOS), anti-oxidative enzyme and sarcoplasmic reticulum Ca2+ ATPase 2 (SERCA2) in the non-infarcted area were assessed between these groups. RESULTS There was significant improvement of systolic function in AMI with PF resection compared with the AMI group in the echocardiogram. Even though the electron microscopic morphology for the mitochondria seems to be similar between the AMI with PF resection and AMI groups, there was an improved expression of PGC-1α and responsive OXPHOS including NDUFB3, NDUFB5 and SDHB are associated with the ATP levels in the AMI with PF resection compared with those in the AMI group. In addition, the expression levels of antioxidant enzymes (MnSOD) and SERCA2 were improved in the AMI with PF resection compared with those in the AMI group. CONCLUSION Surgical resection of PF might ameliorate myocardial mitochondria dysfunction in obese AMI.
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Affiliation(s)
- Ki-Woon Kang
- Division of Cardiology, College of Medicine, Heart Research Institute and Biomedical Research Institute, Chung-Ang University Hospital, Chung-Ang University, Seoul, Korea.
| | - Ju-Young Ko
- College of Pharmacy, Mokpo National University, Muan, Korea
| | - Hyunghee Lee
- Division of Cardiology, College of Medicine, Heart Research Institute and Biomedical Research Institute, Chung-Ang University Hospital, Chung-Ang University, Seoul, Korea
| | - Seung Yong Shin
- Division of Cardiology, College of Medicine, Heart Research Institute and Biomedical Research Institute, Chung-Ang University Hospital, Chung-Ang University, Seoul, Korea
| | - Wang Soo Lee
- Division of Cardiology, College of Medicine, Heart Research Institute and Biomedical Research Institute, Chung-Ang University Hospital, Chung-Ang University, Seoul, Korea
| | - Joonhwa Hong
- Division of Cardiothoracic Surgery, College of Medicine, Chung-Ang University Hospital, Chung-Ang University, Seoul, Korea
| | - Sang-Wook Kim
- Division of Cardiology, College of Medicine, Heart Research Institute and Biomedical Research Institute, Chung-Ang University Hospital, Chung-Ang University, Seoul, Korea
| | - Seong-Kyu Lee
- Department of Biochemistry and Molecular Biology, School of Medicine, Eulji University, Daejeon, Korea
| | - Min-Ho Oak
- College of Pharmacy, Mokpo National University, Muan, Korea.
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2
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Kobak KA, Zarzycka W, Chiao YA. Age and Sex Differences in Heart Failure With Preserved Ejection Fraction. FRONTIERS IN AGING 2022; 3:811436. [PMID: 35821846 PMCID: PMC9261310 DOI: 10.3389/fragi.2022.811436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/13/2022] [Indexed: 11/29/2022]
Abstract
Heart failure with preserved ejection fraction (HFpEF) is a multi-organ disorder that represents about 50% of total heart failure (HF) cases and is the most common form of HF in the elderly. Because of its increasing prevalence caused by the aging population, high mortality and morbidity, and very limited therapeutic options, HFpEF is considered as one of the greatest unmet medical needs in cardiovascular medicine. Despite its complex pathophysiology, numerous preclinical models have been established in rodents and in large animals to study HFpEF pathophysiology. Although age and sex differences are well described in HFpEF population, there are knowledge gaps in sex- and age-specific differences in established preclinical models. In this review, we summarize various strategies that have been used to develop HFpEF models and discuss the knowledge gaps in sex and age differences in HFpEF.
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Ca 2+ mishandling and mitochondrial dysfunction: a converging road to prediabetic and diabetic cardiomyopathy. Pflugers Arch 2022; 474:33-61. [PMID: 34978597 PMCID: PMC8721633 DOI: 10.1007/s00424-021-02650-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 11/17/2021] [Accepted: 12/03/2021] [Indexed: 12/16/2022]
Abstract
Diabetic cardiomyopathy is defined as the myocardial dysfunction that suffers patients with diabetes mellitus (DM) in the absence of hypertension and structural heart diseases such as valvular or coronary artery dysfunctions. Since the impact of DM on cardiac function is rather silent and slow, early stages of diabetic cardiomyopathy, known as prediabetes, are poorly recognized, and, on many occasions, cardiac illness is diagnosed only after a severe degree of dysfunction was reached. Therefore, exploration and recognition of the initial pathophysiological mechanisms that lead to cardiac dysfunction in diabetic cardiomyopathy are of vital importance for an on-time diagnosis and treatment of the malady. Among the complex and intricate mechanisms involved in diabetic cardiomyopathy, Ca2+ mishandling and mitochondrial dysfunction have been described as pivotal early processes. In the present review, we will focus on these two processes and the molecular pathway that relates these two alterations to the earlier stages and the development of diabetic cardiomyopathy.
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Ren J, Wu NN, Wang S, Sowers JR, Zhang Y. Obesity cardiomyopathy: evidence, mechanisms, and therapeutic implications. Physiol Rev 2021; 101:1745-1807. [PMID: 33949876 PMCID: PMC8422427 DOI: 10.1152/physrev.00030.2020] [Citation(s) in RCA: 154] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The prevalence of heart failure is on the rise and imposes a major health threat, in part, due to the rapidly increased prevalence of overweight and obesity. To this point, epidemiological, clinical, and experimental evidence supports the existence of a unique disease entity termed “obesity cardiomyopathy,” which develops independent of hypertension, coronary heart disease, and other heart diseases. Our contemporary review evaluates the evidence for this pathological condition, examines putative responsible mechanisms, and discusses therapeutic options for this disorder. Clinical findings have consolidated the presence of left ventricular dysfunction in obesity. Experimental investigations have uncovered pathophysiological changes in myocardial structure and function in genetically predisposed and diet-induced obesity. Indeed, contemporary evidence consolidates a wide array of cellular and molecular mechanisms underlying the etiology of obesity cardiomyopathy including adipose tissue dysfunction, systemic inflammation, metabolic disturbances (insulin resistance, abnormal glucose transport, spillover of free fatty acids, lipotoxicity, and amino acid derangement), altered intracellular especially mitochondrial Ca2+ homeostasis, oxidative stress, autophagy/mitophagy defect, myocardial fibrosis, dampened coronary flow reserve, coronary microvascular disease (microangiopathy), and endothelial impairment. Given the important role of obesity in the increased risk of heart failure, especially that with preserved systolic function and the recent rises in COVID-19-associated cardiovascular mortality, this review should provide compelling evidence for the presence of obesity cardiomyopathy, independent of various comorbid conditions, underlying mechanisms, and offer new insights into potential therapeutic approaches (pharmacological and lifestyle modification) for the clinical management of obesity cardiomyopathy.
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Affiliation(s)
- Jun Ren
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital Fudan University, Shanghai, China.,Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington
| | - Ne N Wu
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital Fudan University, Shanghai, China
| | - Shuyi Wang
- School of Medicine, Shanghai University, Shanghai, China.,University of Wyoming College of Health Sciences, Laramie, Wyoming
| | - James R Sowers
- Dalton Cardiovascular Research Center, Diabetes and Cardiovascular Research Center, University of Missouri-Columbia, Columbia, Missouri
| | - Yingmei Zhang
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital Fudan University, Shanghai, China
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5
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Maria Z, Campolo AR, Scherlag BJ, Ritchey JW, Lacombe VA. Insulin Treatment Reduces Susceptibility to Atrial Fibrillation in Type 1 Diabetic Mice. Front Cardiovasc Med 2020; 7:134. [PMID: 32903422 PMCID: PMC7434932 DOI: 10.3389/fcvm.2020.00134] [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: 07/31/2019] [Accepted: 06/30/2020] [Indexed: 12/19/2022] Open
Abstract
Diabetes has been identified as an independent risk factor for atrial fibrillation (AF), the most common chronic cardiac arrhythmia. Whether or not glucose and insulin disturbances observed during diabetes enhance arrhythmogenicity of the atria, potentially leading to AF, is not well-known. We hypothesized that insulin deficiency and impaired glucose transport provide a metabolic substrate for the development and maintenance of AF during diabetes. Transesophageal atrial pacing was used to induce AF in healthy, streptozotocin-induced insulin-deficient type 1 diabetic, and insulin-treated diabetic mice. Translocation of insulin-sensitive glucose transporters (GLUTs) to the atrial cell surface was measured using a biotinylated photolabeling assay in the perfused heart. Fibrosis and glycogen accumulation in the atrium were measured using histological analysis. Diabetic mice displayed mild hyperglycemia, increased duration and frequency of AF episodes vs. age-matched controls (e.g., AF duration: 19.7 ± 6.8 s vs. 1.8 ± 1.1 s, respectively, p = 0.032), whereas insulin-treated diabetic animals did not. The translocation of insulin-sensitive GLUT-4 and -8 to the atrial cell surface was significantly downregulated in the diabetic mice (by 67 and 79%, respectively; p ≤ 0.001), and rescued by insulin treatment. We did not observe fibrosis or glycogen accumulation in the atria of diabetic mice. Therefore, these data suggest that insulin and glucose disturbances were sufficient to induce AF susceptibility during mild diabetes.
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Affiliation(s)
- Zahra Maria
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, United States
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Allison R. Campolo
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, United States
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Benjamin J. Scherlag
- Department of Internal Medicine, University of Oklahoma College of Medicine, Oklahoma City, OK, United States
| | - Jerry W. Ritchey
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, United States
| | - Véronique A. Lacombe
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, United States
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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Boldt K, Rios JL, Joumaa V, Herzog W. Mechanical function of cardiac fibre bundles is partly protected by exercise in response to diet-induced obesity in rats. Appl Physiol Nutr Metab 2020; 46:46-54. [PMID: 32598858 DOI: 10.1139/apnm-2020-0275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Decrements in contractile function resulting from obesity are thought to be major reasons for the link between obesity and cardiovascular disease, while exercise has been shown to improve cardiac muscle contractile function. The purpose of this study was to evaluate cardiac contractile properties following obesity induction and the potential protective effect of exercise. Twelve-week-old rats (n = 30) were organized into either a chow diet or a high-fat, high-sucrose (HFHS) diet group. Following 12 weeks of obesity induction the HFHS group animals were stratified and grouped into sedentary (HFHS+Sed) and exercise (HFHS+Ex) groups for an additional 12 weeks. Following 24 weeks of diet intervention, with 12 weeks of aerobic exercise (25 m/min, 30 min/day, 5 days/week) for the HFHS+Ex group, skinned cardiac fibre bundle testing was used to evaluate cardiac contractile properties. Body fat and mass were significantly greater in the HFHS-fed animals compared with the chow controls (p < 0.043). Hearts from rats in the HFHS+Sed group had significantly greater mass (p < 0.03), significantly slower maximum shortening velocity (p = 0.001), and tended to have lower calcium sensitivity (p = 0.077) and a lower proportion of α-myosin heavy chain composition (p = 0.074) than the sedentary chow animals. However, 12 weeks of moderate aerobic exercise partially prevented these decrements in contractile properties. Novelty Cardiac muscle from animals exposed to an obesogenic diet for 24 weeks had impaired contractile properties compared with controls. Obesity-induced impairment of contractile properties of the heart were partially prevented by a 12-week aerobic exercise regime.
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Affiliation(s)
- Kevin Boldt
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Jaqueline Lourdes Rios
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Venus Joumaa
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Walter Herzog
- Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB T2N 1N4, Canada.,Biomechanics Laboratory, School of Sports, Federal University of Santa Catarina, SC 88040-900, Brazil
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7
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Obradovic M, Zafirovic S, Soskic S, Stanimirovic J, Trpkovic A, Jevremovic D, Isenovic ER. Effects of IGF-1 on the Cardiovascular System. Curr Pharm Des 2019; 25:3715-3725. [DOI: 10.2174/1381612825666191106091507] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/29/2019] [Indexed: 11/22/2022]
Abstract
:Cardiovascular (CV) diseases are the most common health problems worldwide, with a permanent increase in incidence. Growing evidence underlines that insulin-like growth factor 1 (IGF-1) is a very important hormone responsible for normal CV system physiology. IGF-1 is an anabolic growth hormone, responsible for cell growth, differentiation, proliferation, and survival. Despite systemic effects, IGF-1 exerts a wide array of influences in the CV system affecting metabolic homeostasis, vasorelaxation, cardiac contractility and hypertrophy, autophagy, apoptosis, and antioxidative processes. The vasodilatory effect of IGF-1, is achieved through the regulation of the activity of endothelial nitric oxide synthase (eNOS) and, at least partly, through enhancing inducible NOS (iNOS) activity. Also, IGF-1 stimulates vascular relaxation through regulation of sodium/potassiumadenosine- triphosphatase. Numerous animal studies provided evidence of diverse influences of IGF-1 in the CV system such as vasorelaxation, anti-apoptotic and prosurvival effects. Human studies indicate that low serum levels of free or total IGF-1 contribute to an increased risk of CV and cerebrovascular disease. Large human trials aiming at finding clinical efficacy and outcome of IGF-1-related therapy are of great interest.:We look forward to the development of new IGF 1 therapies with minor side effects. In this review, we discuss the latest literature data regarding the function of IGF-1 in the CV system in the physiological and pathophysiological conditions.
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Affiliation(s)
- Milan Obradovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Sonja Zafirovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Sanja Soskic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Julijana Stanimirovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Andreja Trpkovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
| | - Danimir Jevremovic
- Faculty of Stomatology, Pancevo, University Business Academy, 21000 Novi Sad, Serbia
| | - Esma R. Isenovic
- Laboratory of Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Petrovica Alasa 12-14, 11000 Belgrade, Serbia
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Valero-Muñoz M, Backman W, Sam F. Murine Models of Heart Failure with Preserved Ejection Fraction: a "Fishing Expedition". JACC Basic Transl Sci 2017; 2:770-789. [PMID: 29333506 PMCID: PMC5764178 DOI: 10.1016/j.jacbts.2017.07.013] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 12/28/2022]
Abstract
Heart failure with preserved ejection fraction (HFpEF) is characterized by signs and symptoms of HF in the presence of a normal left ventricular (LV) ejection fraction (EF). Despite accounting for up to 50% of all clinical presentations of HF, the mechanisms implicated in HFpEF are poorly understood, thus precluding effective therapy. The pathophysiological heterogeneity in the HFpEF phenotype also contributes to this disease and likely to the absence of evidence-based therapies. Limited access to human samples and imperfect animal models that completely recapitulate the human HFpEF phenotype have impeded our understanding of the mechanistic underpinnings that exist in this disease. Aging and comorbidities such as atrial fibrillation, hypertension, diabetes and obesity, pulmonary hypertension and renal dysfunction are highly associated with HFpEF. Yet, the relationship and contribution between them remains ill-defined. This review discusses some of the distinctive clinical features of HFpEF in association with these comorbidities and highlights the advantages and disadvantage of commonly used murine models, used to study the HFpEF phenotype.
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Affiliation(s)
- Maria Valero-Muñoz
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
| | - Warren Backman
- Evans Department of Internal Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Flora Sam
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
- Evans Department of Internal Medicine, Boston University School of Medicine, Boston, Massachusetts
- Cardiovascular Section, Boston University School of Medicine, Boston, Massachusetts
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9
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Francisqueti FV, Nascimento AF, Minatel IO, Dias MC, Luvizotto RDAM, Berchieri-Ronchi C, Ferreira ALA, Corrêa CR. Metabolic syndrome and inflammation in adipose tissue occur at different times in animals submitted to a high-sugar/fat diet. J Nutr Sci 2017; 6:e41. [PMID: 29152245 PMCID: PMC5672321 DOI: 10.1017/jns.2017.42] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 05/23/2017] [Accepted: 06/29/2017] [Indexed: 12/16/2022] Open
Abstract
Obesity is associated with low-grade inflammation, triggered in adipose tissue, which may occur due to an excess of SFA from the diet that can be recognised by Toll-like receptor-4. This condition is involved in the development of components of the metabolic syndrome associated with obesity, especially insulin resistance. The aim of the study was to evaluate the manifestation of the metabolic syndrome and adipose tissue inflammation as a function of the period of time in which rats were submitted to a high-sugar/fat diet (HSF). Male Wistar rats were divided into six groups to receive the control diet (C) or the HSF for 6, 12 or 24 weeks. HSF increased the adiposity index in all HSF groups compared with the C group. HSF was associated with higher plasma TAG, glucose, insulin and leptin levels. Homeostasis model assessment increased in HSF compared with C rats at 24 weeks. Both TNF-α and IL-6 were elevated in the epididymal adipose tissue of HSF rats at 24 weeks compared with HSF at 6 weeks and C at 24 weeks. Only the HSF group at 24 weeks showed increased expression of both Toll-like receptor-4 and NF-κB. More inflammatory cells were found in the HSF group at 24 weeks. We can conclude that the metabolic syndrome occurs independently of the inflammatory response in adipose tissue and that inflammation is associated with hypertrophy of adipocytes, which varies according to duration of exposure to the HSF.
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Affiliation(s)
| | | | - Igor Otávio Minatel
- São Paulo State University, Institute of Bioscience, Botucatu, São Paulo, Brazil
| | - Marcos Correa Dias
- Institute of Health Sciences, Federal University of Mato Grosso (UFMT), Sinop, Mato Grosso, Brazil
| | | | | | - Ana Lúcia A. Ferreira
- São Paulo State University (UNESP), Botucatu Medical School, Botucatu, São Paulo, Brazil
| | - Camila Renata Corrêa
- São Paulo State University (UNESP), Botucatu Medical School, Botucatu, São Paulo, Brazil
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10
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Dose-dependent effect of Bisphenol-A on insulin signaling molecules in cardiac muscle of adult male rat. Chem Biol Interact 2017; 266:10-16. [DOI: 10.1016/j.cbi.2017.01.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/20/2017] [Accepted: 01/26/2017] [Indexed: 01/16/2023]
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11
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Liang Y, Yuan W, Zhu W, Zhu J, Lin Q, Zou X, Deng C, Fu Y, Zheng X, Yang M, Wu S, Yu X, Shan Z. Macrophage migration inhibitory factor promotes expression of GLUT4 glucose transporter through MEF2 and Zac1 in cardiomyocytes. Metabolism 2015; 64:1682-93. [PMID: 26455966 DOI: 10.1016/j.metabol.2015.09.007] [Citation(s) in RCA: 9] [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: 04/07/2015] [Revised: 08/20/2015] [Accepted: 09/08/2015] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Evidence shows that both macrophage migration inhibitory factor (MIF) and GLUT4 glucose transporter are involved in diabetic cardiomyopathy (DCM), but it remains largely unknown whether and how MIF regulates GLUT4 expression in cardiomyocytes. The present study aims to investigate the mechanism underlying the modulation of GLUT4 by MIF in cardiomyocytes. MATERIAL AND METHODS Activations of AKT and AMPK signaling, and expressions of MIF, GLUT4 and the candidate GLUT4 regulation associated transcription factors in the diabetic mouse myocardium were determined. The screened transcription factors mediating MIF-promoted GLUT4 expression were verified by RNA interference (RNAi) and electrophoretic mobility shift assay (EMSA), respectively. RESULTS MIF was increased, but GLUT4 was decreased in the diabetic mouse myocardium. MIF could enhance glucose uptake and up-regulate GLUT4 expression in NMVCs. Expressions of transcription factor MEF2A, -2C, -2D and Zac1 were significantly up-regulated in MIF-treated neonatal mouse ventricular cardiomyocytes (NMVCs), and markedly reduced in the diabetic myocardium. Knockdown of MEF2A, -2C, -2D and Zac1 could significantly inhibit glucose uptake and GLUT4 expression in cardiomyocytes. Moreover, EMSA results revealed that transcriptional activities of MEF2 and Zac1 were significantly increased in MIF-treated NMVCs. AMPK signaling was activated in MIF-stimulated NMVCs, and AMPK activator AICAR could enhance MEF2A, -2C, -2D, Zac1 and GLUT4 expression. Additionally, MIF effects were inhibited by an AMPK inhibitor compound C and siRNA targeting MIF receptor CD74, suggesting the involvement of CD74-dependent AMPK activation. CONCLUSIONS Transcription factor MEF2 and Zac1 mediate MIF-induced GLUT4 expression through CD74-dependent AMPK activation in cardiomyocytes.
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Affiliation(s)
- Yeyou Liang
- Southern Medical University, 1838 Guangzhou Avenue North, Guangzhou, China.
| | - Weiwei Yuan
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Wensi Zhu
- Southern Medical University, 1838 Guangzhou Avenue North, Guangzhou, China.
| | - Jiening Zhu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Qiuxiong Lin
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xiao Zou
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Chunyu Deng
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Yongheng Fu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xilong Zheng
- The Libin Cardiovascular Institute of AB, Department of Biochemistry & Molecular Biology, Cumming School of Medicine, The University of Calgary, Calgary, Canada.
| | - Min Yang
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Shulin Wu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xiyong Yu
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Zhixin Shan
- Medical Research Center of Guangdong General Hospital, Guangdong Provincial Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
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12
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20 years of leptin: Role of leptin in cardiomyocyte physiology and physiopathology. Life Sci 2015; 140:10-8. [PMID: 25748420 DOI: 10.1016/j.lfs.2015.02.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 02/14/2015] [Indexed: 02/08/2023]
Abstract
Since the discovery of leptin in 1994 by Zhang et al., there have been a number of reports showing its implication in the development of a wide range of cardiovascular diseases. However, there exists some controversy about how leptin can induce or preserve cardiovascular function, as different authors have found contradictory results about leptin beneficial or detrimental effects in leptin deficient/resistant murine models and in wild type tissue and cardiomyocytes. Here, we will focus on the main discoveries about the leptin functions at cardiac level within the last two decades, focusing on its role in cardiac metabolism, remodeling and contractile function.
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13
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Franekova V, Angin Y, Hoebers NTH, Coumans WA, Simons PJ, Glatz JFC, Luiken JJFP, Larsen TS. Marine omega-3 fatty acids prevent myocardial insulin resistance and metabolic remodeling as induced experimentally by high insulin exposure. Am J Physiol Cell Physiol 2015; 308:C297-307. [DOI: 10.1152/ajpcell.00073.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Insulin resistance is an important risk factor for the development of several cardiac pathologies, thus advocating strategies for restoring insulin sensitivity of the heart in these conditions. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs), mainly eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3), have been shown to improve insulin sensitivity in insulin-sensitive tissues, but their direct effect on insulin signaling and metabolic parameters in the myocardium has not been reported previously. The aim of this study was therefore to examine the ability of EPA and DHA to prevent insulin resistance in isolated rat cardiomyocytes. Primary rat cardiomyocytes were made insulin resistant by 48 h incubation in high insulin (HI) medium. Parallel incubations were supplemented by 200 μM EPA or DHA. Addition of EPA or DHA to the medium prevented the induction of insulin resistance in cardiomyocytes by preserving the phosphorylation state of key proteins in the insulin signaling cascade and by preventing persistent relocation of fatty acid transporter CD36 to the sarcolemma. Only cardiomyocytes incubated in the presence of EPA, however, exhibited improvements in glucose and fatty acid uptake and cell shortening. We conclude that ω-3 PUFAs protect metabolic and functional properties of cardiomyocytes subjected to insulin resistance-evoking conditions.
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Affiliation(s)
- Veronika Franekova
- Cardiovascular Research Group, Department of Medical Biology, Health Sciences Faculty, UiT The Arctic University of Norway, Tromsø, Norway
| | - Yeliz Angin
- Department of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands; and
| | - Nicole T. H. Hoebers
- Department of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands; and
| | - Will A. Coumans
- Department of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands; and
| | | | - Jan F. C. Glatz
- Department of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands; and
| | - Joost J. F. P. Luiken
- Department of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands; and
| | - Terje S. Larsen
- Cardiovascular Research Group, Department of Medical Biology, Health Sciences Faculty, UiT The Arctic University of Norway, Tromsø, Norway
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14
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Horgan S, Watson C, Glezeva N, Baugh J. Murine models of diastolic dysfunction and heart failure with preserved ejection fraction. J Card Fail 2014; 20:984-95. [PMID: 25225111 DOI: 10.1016/j.cardfail.2014.09.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 08/12/2014] [Accepted: 09/05/2014] [Indexed: 12/14/2022]
Abstract
Left ventricular diastolic dysfunction leads to heart failure with preserved ejection fraction, an increasingly prevalent condition largely driven by modern day lifestyle risk factors. As heart failure with preserved ejection fraction accounts for almost one-half of all patients with heart failure, appropriate nonhuman animal models are required to improve our understanding of the pathophysiology of this syndrome and to provide a platform for preclinical investigation of potential therapies. Hypertension, obesity, and diabetes are major risk factors for diastolic dysfunction and heart failure with preserved ejection fraction. This review focuses on murine models reflecting this disease continuum driven by the aforementioned common risk factors. We describe various models of diastolic dysfunction and highlight models of heart failure with preserved ejection fraction reported in the literature. Strengths and weaknesses of the different models are discussed to provide an aid to translational scientists when selecting an appropriate model. We also bring attention to the fact that heart failure with preserved ejection fraction is difficult to diagnose in animal models and that, therefore, there is a paucity of well described animal models of this increasingly important condition.
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Affiliation(s)
- S Horgan
- School of Medicine and Medical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland; Noninvasive Cardiovascular Imaging, Brigham and Women's Hospital, Boston, Massachusetts.
| | - C Watson
- School of Medicine and Medical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - N Glezeva
- School of Medicine and Medical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - J Baugh
- School of Medicine and Medical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
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15
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Carvajal K, Balderas-Villalobos J, Bello-Sanchez MD, Phillips-Farfán B, Molina-Muñoz T, Aldana-Quintero H, Gómez-Viquez NL. Ca(2+) mishandling and cardiac dysfunction in obesity and insulin resistance: role of oxidative stress. Cell Calcium 2014; 56:408-15. [PMID: 25168907 DOI: 10.1016/j.ceca.2014.08.003] [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: 05/29/2014] [Revised: 08/01/2014] [Accepted: 08/02/2014] [Indexed: 12/12/2022]
Abstract
Obesity and insulin resistance (IR) are strongly connected to the development of subclinical cardiac dysfunction and eventually can lead to heart failure, which is the main cause of morbidity and death in patients having these metabolic diseases. It has been considered that excessive fat tissue may play a critical role in producing systemic IR and enhancing reactive oxygen species (ROS) generation. This oxidative stress (OS) may elicit or exacerbate IR. On the other hand, evidence suggests that some of the cellular mechanisms involved in the pathophysiology of obesity and IR-related cardiomyopathy are excessive myocardial ROS production and abnormal Ca(2+) homeostasis. In addition, emerging evidence suggests that augmented ROS production may contribute to Ca(2+) mishandling by affecting the redox state of key proteins implicated in this process. In this review, we focus on the role of Ca(2+) mishandling in the development of cardiac dysfunction in obesity and IR and address the evidence suggesting that OS might also contribute to cardiac dysfunction by affecting Ca(2+) handling.
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Affiliation(s)
- Karla Carvajal
- Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Jaime Balderas-Villalobos
- Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Mexico City, Mexico; Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Ma Dolores Bello-Sanchez
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Bryan Phillips-Farfán
- Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Tzindilu Molina-Muñoz
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Hugo Aldana-Quintero
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Norma L Gómez-Viquez
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico.
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16
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Kavak S. Effects of Insulin on Altered Mechanical and Electrical Papillary Muscle Activities of Diabetic Rats. J Membr Biol 2012; 246:31-7. [DOI: 10.1007/s00232-012-9499-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 08/18/2012] [Indexed: 10/27/2022]
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17
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Maternal obesity, lipotoxicity and cardiovascular diseases in offspring. J Mol Cell Cardiol 2012; 55:111-6. [PMID: 22982026 DOI: 10.1016/j.yjmcc.2012.08.023] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Revised: 08/28/2012] [Accepted: 08/28/2012] [Indexed: 02/02/2023]
Abstract
Maternal obesity has risen dramatically over the past 20 years, by nearly 42% in African-Americans and 29% in Caucasians. Maternal obesity is afflicted with many maternal obstetric complications in the offspring including high blood pressure, obesity, gestational diabetes and increased perinatal morbidity. Maternal nutritional environment plays a rather important role in the programming of the health set-points in the offspring such as glucose and insulin metabolism, energy balance and predisposition to metabolic disorders. In particular, maternal obesity is associated with elevated prevalence of cardiovascular diseases in the offspring. Evidence from human and experimental studies including rodents and nonhuman primates has indicated that maternal obesity or overnutrition programs offspring for an increased risk of adult obesity. Maternal obesity or fat diet exposure predisposes the onset and development of obesity, insulin resistance, cardiac hypertrophy and myocardial contractile anomalies in the offspring. A number of mechanisms including elevated hormones (leptin, insulin), nutrients (fatty acids, triglycerides and glucose) and inflammatory cytokines have been postulated to play a key role in maternal obesity-induced postnatal cardiovascular sequelae. In addition, lipotoxicity (accumulation of lipid metabolites) resulting from maternal obesity is capable of activating a number of stress signaling cascades including pro-inflammatory cytokines and oxidative stress to exacerbate maternal obesity-induced cardiovascular complications later on in adult life. This mini-review summarizes the recent knowledge with regard to the role of lipotoxicity in maternal obesity-induced change in cardiovascular function in the offspring. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism".
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18
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Han X, Turdi S, Hu N, Guo R, Zhang Y, Ren J. Influence of long-term caloric restriction on myocardial and cardiomyocyte contractile function and autophagy in mice. J Nutr Biochem 2012; 23:1592-9. [PMID: 22444502 DOI: 10.1016/j.jnutbio.2011.11.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 10/29/2011] [Accepted: 11/03/2011] [Indexed: 11/20/2022]
Abstract
Both clinical and experimental evidence has revealed that calorie restriction (CR) is capable of improving heart function. However, most the reports are focused on the effect of CR on the pathological states such as obesity, while the effect of CR on heart function in otherwise healthy subjects is not well understood. This study examined the long-term CR effect on cardiac contractile function and possible underlying mechanisms involved. C57BL/6 mice were subjected to a 40% CR or ad libitum feeding for 20 weeks. Echocardiographic and cardiomyocyte contractile properties were evaluated. Intracellular signaling pathways were examined using Western blot analysis. Our results showed that CR overtly lessened glucose intolerance, lessened body and heart weights (although not heart size), lowered fat tissue density, decreased left ventricular (LV) wall thickness (septum and posterior wall) in both systole and diastole, and reduced LV mass (not normalized LV mass) without affecting fractional shortening. Cardiomyocyte cell length and cross-sectional area were reduced, while peak shortening amplitude was increased following CR. CR failed to affect maximal velocity of shortening/relengthening and duration of shortening and relengthening. Immunoblotting data depicted decreased and increased phosphorylation of Akt/glycogen synthase kinase-3β and AMP-dependent protein kinase/acetyl-CoA carboxylase, respectively, following CR. CR also dampened the phosphorylation of mammalian target of rapamycin, extracellular-signal-regulated protein kinase 1/2 and c-Jun, while it increased the phosphorylation of c-Jun NH2-terminal kinase. Last but not least, CR significantly promoted cardiac autophagy as evidenced by increased expression of LC3B-II (and LC3B-II to LC3B-I ratio) and Beclin-1. In summary, our data suggested that long-term CR may preserve cardiac contractile function with improved cardiomyocyte function, lessen cardiac remodeling and promote autophagy.
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Affiliation(s)
- Xuefeng Han
- Department of Physiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China 710032
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19
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Lin YC, Huang J, Kan H, Castranova V, Frisbee JC, Yu HG. Defective calcium inactivation causes long QT in obese insulin-resistant rat. Am J Physiol Heart Circ Physiol 2011; 302:H1013-22. [PMID: 22198168 DOI: 10.1152/ajpheart.00837.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The majority of diabetic patients who are overweight or obese die of heart disease. We suspect that the obesity-induced insulin resistance may lead to abnormal cardiac electrophysiology. We tested this hypothesis by studying an obese insulin-resistant rat model, the obese Zucker rat (OZR). Compared with the age-matched control, lean Zucker rat (LZR), OZR of 16-17 wk old exhibited an increase in QTc interval, action potential duration, and cell capacitance. Furthermore, the L-type calcium current (I(CaL)) in OZR exhibited defective inactivation and lost the complete inactivation back to the closed state, leading to increased Ca(2+) influx. The current density of I(CaL) was reduced in OZR, whereas the threshold activation and the current-voltage relationship of I(CaL) were not significantly altered. L-type Ba(2+) current (I(BaL)) in OZR also exhibited defective inactivation, and steady-state inactivation was not significantly altered. However, the current-voltage relationship and activation threshold of I(BaL) in OZR exhibited a depolarized shift compared with LZR. The total and membrane protein expression levels of Cav1.2 [pore-forming subunit of L-type calcium channels (LTCC)], but not the insulin receptors, were decreased in OZR. The insulin receptor was found to be associated with the Cav1.2, which was weakened in OZR. The total protein expression of calmodulin was reduced, but that of Cavβ2 subunit was not altered in OZR. Together, these results suggested that the 16- to 17-wk-old OZR has 1) developed cardiac hypertrophy, 2) exhibited altered electrophysiology manifested by the prolonged QTc interval, 3) increased duration of action potential in isolated ventricular myocytes, 4) defective inactivation of I(CaL) and I(BaL), 5) weakened the association of LTCC with the insulin receptor, and 6) decreased protein expression of Cav1.2 and calmodulin. These results also provided mechanistic insights into a remodeled cardiac electrophysiology under the condition of insulin resistance, enhancing our understanding of long QT associated with obese type 2 diabetic patients.
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Affiliation(s)
- Yen-Chang Lin
- Center for Cardiovascular and Respiratory Sciences, Department of Physiology and Pharmacology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26056, USA.
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20
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Guiducci L, Burchielli S, Chubuchny V, Sicari R, Liistro T, Corciu AI, Pardini S, Di Cecco P, Manfredi S, Bucci M, Salvadori PA, Andreassi MG, Iozzo P. Maternal and Sex Dependency of Insulin Resistance: Longitudinal PET and Echocardiography Study from the Healthy Fetus to the Adult Minipig. J Nucl Med 2011; 52:1993-2000. [DOI: 10.2967/jnumed.111.087882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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21
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Soskić SS, Dobutović BD, Sudar EM, Obradović MM, Nikolić DM, Djordjevic JD, Radak DJ, Mikhailidis DP, Isenović ER. Regulation of Inducible Nitric Oxide Synthase (iNOS) and its Potential Role in Insulin Resistance, Diabetes and Heart Failure. Open Cardiovasc Med J 2011; 5:153-63. [PMID: 21792376 PMCID: PMC3141344 DOI: 10.2174/1874192401105010153] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 05/30/2011] [Accepted: 05/31/2011] [Indexed: 02/08/2023] Open
Abstract
Nitric oxide synthases (NOS) are the enzymes responsible for nitric oxide (NO) generation. NO is a reactive oxygen species as well as a reactive nitrogen species. It is a free radical which mediates several biological effects. It is clear that the generation and actions of NO under physiological and pathophysiological conditions are regulated and extend to almost every cell type and function within the circulation. In mammals 3 distinct isoforms of NOS have been identified: neuronal NOS (nNOS), inducible NOS (iNOS) and endothelial NOS (eNOS). The important isoform in the regulation of insulin resistance (IR) is iNOS. Understanding the molecular mechanisms regulating the iNOS pathway in normal and hyperglycemic conditions would help to explain some of vascular abnormalities observed in type 2 diabetes mellitus (T2DM). Previous studies have reported increased myocardial iNOS activity and expression in heart failure (HF). This review considers the recent animal studies which focus on the understanding of regulation of iNOS activity/expression and the role of iNOS agonists as potential therapeutic agents in treatment of IR, T2DM and HF.
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Affiliation(s)
- Sanja S Soskić
- Laboratory for Radiobiology and Molecular Genetics, Institute "Vinča", University of Belgrade, Serbia
| | - Branislava D Dobutović
- Laboratory for Radiobiology and Molecular Genetics, Institute "Vinča", University of Belgrade, Serbia
| | - Emina M Sudar
- Laboratory for Radiobiology and Molecular Genetics, Institute "Vinča", University of Belgrade, Serbia
| | - Milan M Obradović
- Laboratory for Radiobiology and Molecular Genetics, Institute "Vinča", University of Belgrade, Serbia
| | - Dragana M Nikolić
- Laboratory for Radiobiology and Molecular Genetics, Institute "Vinča", University of Belgrade, Serbia
| | - Jelena D Djordjevic
- Institute of Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, P.O.Box S2 Republic of Serbia
| | - Djordje J Radak
- Department of Vascular Surgery, Dedinje Cardiovascular Institute, Belgrade University School of Medicine, Belgrade, Serbia
| | - Dimitri P Mikhailidis
- Department of Clinical Biochemistry (Vascular Disease Prevention Clinics), Royal Free campus, University College London Medical School, University College London (UCL), Pond Street, London NW3 2QG, UK
| | - Esma R Isenović
- Laboratory for Radiobiology and Molecular Genetics, Institute "Vinča", University of Belgrade, Serbia
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22
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Santos JLF, Salemi VMC, Picard MH, Mady C, Coelho OR. Subclinical regional left ventricular dysfunction in obese patients with and without hypertension or hypertrophy. Obesity (Silver Spring) 2011; 19:1296-303. [PMID: 20966911 DOI: 10.1038/oby.2010.253] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We investigated the impact of obesity on the abnormalities of systolic and diastolic regional left ventricular (LV) function in patients with or without hypertension or hypertrophy, and without heart failure. We studied 120 individuals divided into 6 groups of 20 patients (42 ± 6 years, 60 females) using standard and pulsed-wave tissue Doppler imaging (TDI) echocardiography, and heterogeneity index (HI): nonobese (I: no hypertension, no hypertrophy, control group; II: hypertension, no hypertrophy; III: hypertension and hypertrophy) and obese (IV: no hypertension, no hypertrophy; V: hypertension, no hypertrophy; VI: hypertension and hypertrophy). The criterion for obesity was BMI ≥30 kg/m2, for hypertension was blood pressure ≥ 140/90 mm Hg, for hypertrophy in nonobese was LV mass/body surface area (BSA) >134 g/m(2) (men) and >110 mg/m2 (women), and in obese was LV mass/height(2.7) >50 (men) and >40 (women). Obese groups had normal LV ejection fraction compared with nonobese groups, but decreased longitudinal and radial systolic myocardial peak velocities (S'), and early diastolic myocardial peak velocity (E'). Also, a great variability of E' and late diastolic myocardial peak velocity (A') from the longitudinal basal region was observed in obese groups (E'basal nonobese: 11 ± 7 vs. obese 19 ± 11, P < 0.001, A'basal nonobese: 7 ± 4 vs. obese 11 ± 7, P < 0.001). Our findings were more evident when comparing groups IV with V and VI, with the latter having concentric hypertrophy and obvious segmental systolic and diastolic dysfunctions. Subclinical myocardial alterations and increased variability of the velocities were observed in obese groups, especially with hypertension and hypertrophy, reflecting impaired regional LV relaxation, segmental atrial, and systolic dysfunctions.
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Affiliation(s)
- José L F Santos
- Faculdade de Ciências Médicas da Universidade Estadual de Campinas UNICAMP, São Paulo, Brazil
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23
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Pulakat L, DeMarco VG, Whaley-Connell A, Sowers JR. The Impact of Overnutrition on Insulin Metabolic Signaling in the Heart and the Kidney. Cardiorenal Med 2011; 1:102-112. [PMID: 22258397 DOI: 10.1159/000327140] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Overnutrition characterized by overconsumption of food rich in fat and carbohydrates is a significant contributor to hypertension, type 2 diabetes, and the cardiorenal syndrome. Overnutrition activates the renin-angiotensin-aldosterone system (RAAS) and causes chronic exposure of cardiovascular and renal tissue to increased circulating nutrients, insulin (INS), and angiotensin II (ANG II). Emerging evidence suggests that overnutrition, aldosterone, and ANG II promote INS resistance, a chronic condition that underlies these co-morbidities, through activation of the mammalian target of the rapamycin (mTOR)/S6 kinase 1 (S6K1) signaling pathway in cardiovascular tissue and the kidney. However, a novel ANG II type 2 receptor (AT2R)-mediated cross talk between the RAAS and mTOR pathways ameliorates overnutrition-induced activation of mTOR/S6K1 signaling in cardiovascular tissue of rats, mice, and humans and confers cardioprotection.
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24
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Klachko D, Whaley-Connell A. Use of Metformin in Patients with Kidney and Cardiovascular Diseases. Cardiorenal Med 2011; 1:87-95. [PMID: 22294985 PMCID: PMC3263972 DOI: 10.1159/000327151] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Metformin is an insulin-sensitizing agent with anti-hyperglycemic properties that is widely used for the treatment of type-2 diabetes. The efficacy of metformin in reducing hyperglycemia is well established, and there is emerging evidence that its chronic use is associated with cancer and cardiovascular disease (CVD) risk reduction. While the hypoglycemic properties of metformin are largely attributed to suppression of hepatic glucose production and increases in peripheral tissue insulin sensitivity, the precise mechanism of the hypoglycemic action of metformin remains unclear. There is evidence that metformin use interrupts mitochondrial oxidative stress in the liver and corrects abnormalities of intracellular calcium metabolism in insulin-sensitive tissues (liver, skeletal muscle, and adipocytes) and cardiovascular tissue. However, the use of metformin in patients with kidney disease, a high-risk CVD state, is confounded by confusion regarding appropriate concerns about the development of lactic acidosis in this population. Thus, we will review current evidence on metformin use for improving CVD outcomes and its therapeutic use in kidney disease.
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Affiliation(s)
- David Klachko
- Division of Endocrinology, University of Missouri-Columbia School of Medicine, Columbia, Mo., USA
| | - Adam Whaley-Connell
- Division of Nephrology, Department of Internal Medicine, University of Missouri-Columbia School of Medicine, Columbia, Mo., USA
- Division of Harry S. Truman VA Medical Center, Columbia, Mo., USA
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25
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von Lewinski D, Gasser R, Rainer PP, Huber MS, Wilhelm B, Roessl U, Haas T, Wasler A, Grimm M, Bisping E, Pieske B. Functional effects of glucose transporters in human ventricular myocardium. Eur J Heart Fail 2011; 12:106-13. [PMID: 20083620 DOI: 10.1093/eurjhf/hfp191] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Insulin-dependent positive inotropic effects (PIE) are partially Ca(2+) independent. This mechanism is potentially glucose dependent. In contrast to most animal species, human myocardium expresses high levels of sodium-glucose-transporter-1 (SGLT-1) mRNA besides the common glucose-transporters-1 and -4 (GLUT1, GLUT4). METHODS AND RESULTS We used ventricular myocardium from 61 end-stage failing human hearts (ischaemic cardiomyopathy, ICM and dilated cardiomyopathy, DCM) and 13 non-failing donor hearts. The effect of insulin on isometric twitch force was examined with or without blocking of PI3-kinase, GLUT4-translocation, or SGLT-1. Substrate-dependent (glucose vs. pyruvate vs. palmitoyl-carnitine) effects were tested in atrial myocardium. mRNA expression of glucose transporters was analysed. Insulin increased developed force by 122 + or - 7.4, 121.7 + or - 2.5, and 134.1 + or - 5.7% in non-failing, DCM, and ICM (P < 0.05 vs. DCM), respectively. Positive inotropic effect was partially blunted by inhibition of PI-3-kinase, GLUT4, or SGLT1. Combined inhibition of PI3-kinase and glucose-transport completely abolished PIE. Positive inotropic effect was significantly stronger in glucose-containing solution compared with pyruvate or palmitoyl-carnitine containing. mRNA expression showed only a tendency towards elevated GLUT4-expression in ICM. CONCLUSIONS Positive inotropic effect of insulin is pronounced in ICM, but underlying mechanisms are unaltered. The Ca(2+)-independent PIE of insulin is mediated via glucose-transporters. Together with the Ca(2+)-dependent PI-3-kinase mediated pathway, it is responsible for the entire PIE. Substrate-dependency affirms a glucose-dependent part of the PIE.
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Affiliation(s)
- Dirk von Lewinski
- Department of Cardiology, Working Group Metabolism and Energetics, Medical University Graz, Graz, Austria.
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26
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Whaley-Connell A, Pulakat L, DeMarco VG, Hayden MR, Habibi J, Henriksen EJ, Sowers JR. Overnutrition and the Cardiorenal Syndrome: Use of a Rodent Model to Examine Mechanisms. Cardiorenal Med 2011; 1:23-30. [PMID: 22258463 DOI: 10.1159/000322827] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Obesity has reached epidemic proportions with far-reaching health care and economic implications. Overnutrition, characterized by excess intake of carbohydrates and fats, has been associated with end-organ damage in several tissues, including the heart and the kidney. Furthermore, overnutrition is one of the most important modifiable and preventable causes of morbidity and mortality associated with cardiovascular and kidney diseases. Insulin resistance and compensatory hyperinsulinemia as well as associated mechanisms, including enhanced renin-angiotensin-aldosterone system activity, inflammation, and oxidative stress, have been implicated in obesity-related cardiorenal injury. In this review, the effect of overnutrition on heart and kidney disease is assessed in a rodent model of overnutrition and obesity, the Zucker obese rat.
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27
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von Lewinski D, Rainer PP, Gasser R, Huber MS, Khafaga M, Wilhelm B, Haas T, Mächler H, Rössl U, Pieske B. Glucose-transporter-mediated positive inotropic effects in human myocardium of diabetic and nondiabetic patients. Metabolism 2010; 59:1020-8. [PMID: 20045149 DOI: 10.1016/j.metabol.2009.10.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2009] [Revised: 10/25/2009] [Accepted: 10/26/2009] [Indexed: 11/16/2022]
Abstract
Insulin causes inotropic effects via Ca(2+)-dependent and Ca(2+)-independent pathways. The latter one is potentially glucose dependent. We examined inotropic responses and signal transduction of insulin in human atrial myocardium of diabetic and nondiabetic patients to test for the role of glucose transporters. Experiments were performed in isolated atrial myocardium of 88 patients undergoing cardiac surgery and 28 ventricular muscle samples of explanted hearts. Influence of insulin (0.02 micromol/L) on isometric twitch force was examined with and without blocking glucose transporter (GLUT) 4 translocation (latrunculin), sodium-coupled glucose transporter (SGLT) 1 (phlorizin, T-1095A), or PI3-kinase (wortmannin). Experiments were performed in Tyrode solution containing glucose or pyruvate as energetic substrate. Messenger RNA expression of glucose transporters (GLUT1, GLUT4, SGLT1, SGLT2) was analyzed in atrial and ventricular myocardium of both diabetic and nondiabetic patients. Developed force increases after insulin (to 117.8% +/- 2.4% and 115.8% +/- 1.9%) in trabeculae from patients with and without diabetes. Inotropic effect was reduced after displacing glucose with pyruvate as well as after PI3-kinase inhibition (to 103% +/- 2%) or inhibition of glucose transporters GLUT4 (to 105% +/- 2%) and SGLT1 (phlorizin to 106% +/- 2%, T-1095A to 105% +/- 2%), without differences between the 2 groups. In glucose-free pyruvate-containing solution, only inhibition of PI3-kinase but not blocking glucose transporters resulted in further inhibitory effects. Messenger RNA expression did not show significant differences between patients with or without diabetes. Insulin exerts positive inotropic effects in human atrial myocardium. These effects are mediated via a PI3-kinase-sensitive and a glucose-transport-sensitive pathway. Differences in functional effects or messenger RNA expression of glucose transporters were not detectable between patients with and without diabetes.
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28
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Interaction between age and obesity on cardiomyocyte contractile function: role of leptin and stress signaling. PLoS One 2010; 5:e10085. [PMID: 20396382 PMCID: PMC2852499 DOI: 10.1371/journal.pone.0010085] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 03/17/2010] [Indexed: 12/31/2022] Open
Abstract
Objectives This study was designed to evaluate the interaction between aging and obesity
on cardiac contractile and intracellular Ca2+
properties. Methods Cardiomyocytes from young (4-mo) and aging (12- and 18-mo) male lean and the
leptin deficient ob/ob obese mice were treated with leptin
(0.5, 1.0 and 50 nM) for 4 hrs in vitro. High fat diet
(45% calorie from fat) and the leptin receptor mutant
db/db obesity models at young and older age were used
for comparison. Cardiomyocyte contractile and intracellular
Ca2+ properties were evaluated including peak
shortening (PS), maximal velocity of shortening/relengthening (±
dL/dt), time-to-PS (TPS), time-to-90% relengthening
(TR90), intracellular Ca2+ levels and
decay. O2− levels were measured by
dihydroethidium fluorescence. Results Our results revealed reduced survival in ob/ob mice. Aging
and obesity reduced PS, ± dL/dt, intracellular
Ca2+ rise, prolonged TR90 and
intracellular Ca2+ decay, enhanced
O2− production and
p47phox expression
without an additive effect of the two, with the exception of intracellular
Ca2+ rise. Western blot analysis exhibited reduced
Ob-R expression and STAT-3 phosphorylation in both young and aging
ob/ob mice, which was restored by leptin. Aging and
obesity reduced phosphorylation of Akt, eNOS and p38 while promoting pJNK
and pIκB. Low levels of leptin reconciled contractile, intracellular
Ca2+ and cell signaling defects as well as
O2− production and
p47phox upregulation in
young but not aging ob/ob mice. High level of leptin (50
nM) compromised contractile and intracellular Ca2+
response as well as O2− production and
stress signaling in all groups. High fat diet-induced and
db/db obesity displayed somewhat comparable
aging-induced mechanical but not leptin response. Conclusions Taken together, our data suggest that aging and obesity compromise cardiac
contractile function possibly via phosphorylation of Akt, eNOS and stress
signaling-associated O2− release.
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Majane OHI, Vengethasamy L, du Toit EF, Makaula S, Woodiwiss AJ, Norton GR. Dietary-induced obesity hastens the progression from concentric cardiac hypertrophy to pump dysfunction in spontaneously hypertensive rats. Hypertension 2009; 54:1376-83. [PMID: 19841294 DOI: 10.1161/hypertensionaha.108.127514] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We explored whether dietary-induced obesity hastens the transition from concentric left ventricular (LV) hypertrophy to pump dysfunction in spontaneously hypertensive rats (SHRs) and the mechanisms thereof. After feeding rats a diet for 4 to 5 months, obesity was induced in SHRs and Wistar-Kyoto (WKY) control rats. Obesity was not associated with abnormal blood glucose control (glycosylated hemoglobin) or with increases in systolic blood pressure. However, in SHRs, but not in WKY rats, obesity was associated with a reduced LV chamber systolic function, as determined by echocardiography, and in isolated perfused heart studies. A marked increase in LV end diastolic diameter and a right shift in the LV diastolic pressure-volume relation were noted in obese SHRs but not in obese WKY rats. Moreover, LV intrinsic myocardial systolic function, as determined from the slope of the linearized LV systolic stress-strain relationship (LV myocardial end systolic elastance), was markedly reduced in obese as compared with lean SHRs, whereas LV myocardial end systolic elastance was maintained in obese WKY rats. Obesity increased LV weight, cardiomyocyte width, cardiomyocyte apoptosis (TUNEL), the activity of myocardial matrix metalloproteinases (zymography), and serum leptin concentrations in SHRs but not in WKY rats. In conclusion, SHRs are susceptible to the adverse effects of dietary-induced obesity on the heart, an effect that hastens the progression from concentric LV hypertrophy to pump dysfunction independent of blood pressure changes or alterations in glycosylated hemoglobin. This effect may be mediated through a proclivity of SHRs to developing both obesity-induced effects on cardiomyocyte apoptosis and activation of myocardial collagenases through leptin resistance and obesity-induced hypertrophy.
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Affiliation(s)
- Olebogeng H I Majane
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, University of the Witwatersrand Medical School, 7 York Rd, Parktown, 2193 Johannesburg, South Africa
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Abstract
Diabetic heart disease contributes to the high mortality in diabetics, although effective clinical management is lacking. The protease inhibitor 5-[5-(2-nitrophenyl) furfuryliodine]-1,3-diphenyl-2-thiobarbituric acid (UCF-101) was reported to protect the hearts against ischemic injury. This study examined the role of UCF-101 on streptozotocin (STZ)-induced diabetic heart defect. Vehicle or UCF-101 was administrated to STZ diabetic mice, and cardiomyocyte mechanical properties were analyzed. UCF-101 reduced STZ-induced hyperglycemia and alleviated STZ-induced aberration in cardiomyocyte contractile mechanics. Diabetes dramatically decreased AMPK phosphorylation at Thr(172) of catalytic alpha-subunit, which was restored by UCF-101. Neither diabetes nor UCF-101 affected the expression of HtrA2/Omi and XIAP or caspase-3 activity. The AMPK activator resveratrol mimicked the UCF-101-induced beneficial effect against diabetic cardiac dysfunction. Mechanical properties in cardiomyocytes from the AMPK-kinase-dead (KD) mice displayed markedly impaired contractile function reminiscent of diabetes. STZ injection in AMPK-KD mice failed to elicit any additional cardiomyocyte contractile defect. UCF-101 significantly downregulated the AMPK-degrading enzymes PP2A and PP2C, the effect of which was mimicked by resveratrol. Taken together, these results indicate that UCF-101 protects against STZ-induced cardiac dysfunction, possibly through AMPK signaling.
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Affiliation(s)
- Qun Li
- Division of Pharmaceutical Sciences, University of Wyoming, Laramie, WY 82071, USA
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31
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van den Brom CE, Huisman MC, Vlasblom R, Boontje NM, Duijst S, Lubberink M, Molthoff CFM, Lammertsma AA, van der Velden J, Boer C, Ouwens DM, Diamant M. Altered myocardial substrate metabolism is associated with myocardial dysfunction in early diabetic cardiomyopathy in rats: studies using positron emission tomography. Cardiovasc Diabetol 2009; 8:39. [PMID: 19624828 PMCID: PMC2722582 DOI: 10.1186/1475-2840-8-39] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Accepted: 07/22/2009] [Indexed: 01/08/2023] Open
Abstract
Background In vitro data suggest that changes in myocardial substrate metabolism may contribute to impaired myocardial function in diabetic cardiomyopathy (DCM). The purpose of the present study was to study in a rat model of early DCM, in vivo changes in myocardial substrate metabolism and their association with myocardial function. Methods Zucker diabetic fatty (ZDF) and Zucker lean (ZL) rats underwent echocardiography followed by [11C]palmitate positron emission tomography (PET) under fasting, and [18F]-2-fluoro-2-deoxy-D-glucose PET under hyperinsulinaemic euglycaemic clamp conditions. Isolated cardiomyocytes were used to determine isometric force development. Results PET data showed a 66% decrease in insulin-mediated myocardial glucose utilisation and a 41% increase in fatty acid (FA) oxidation in ZDF vs. ZL rats (both p < 0.05). Echocardiography showed diastolic and systolic dysfunction in ZDF vs. ZL rats, which was paralleled by a significantly decreased maximal force (68%) and maximal rate of force redevelopment (69%) of single cardiomyocytes. Myocardial functional changes were significantly associated with whole-body insulin sensitivity and decreased myocardial glucose utilisation. ZDF hearts showed a 68% decrease in glucose transporter-4 mRNA expression (p < 0.05), a 22% decrease in glucose transporter-4 protein expression (p = 0.10), unchanged levels of pyruvate dehydrogenase kinase-4 protein expression, a 57% decreased phosphorylation of AMP activated protein kinase α1/2 (p < 0.05) and a 2.4-fold increased abundance of the FA transporter CD36 to the sarcolemma (p < 0.01) vs. ZL hearts, which are compatible with changes in substrate metabolism. In ZDF vs. ZL hearts a 2.4-fold reduced insulin-mediated phosphorylation of Akt was found (p < 0.05). Conclusion Using PET and echocardiography, we found increases in myocardial FA oxidation with a concomitant decrease of insulin-mediated myocardial glucose utilisation in early DCM. In addition, the latter was associated with impaired myocardial function. These in vivo data expand previous in vitro findings showing that early alterations in myocardial substrate metabolism contribute to myocardial dysfunction.
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Affiliation(s)
- Charissa E van den Brom
- Department of Endocrinology, Diabetes Centre, VU University Medical Centre, Amsterdam, The Netherlands.
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Olivares-Reyes JA, Arellano-Plancarte A, Castillo-Hernandez JR. Angiotensin II and the development of insulin resistance: implications for diabetes. Mol Cell Endocrinol 2009; 302:128-39. [PMID: 19150387 DOI: 10.1016/j.mce.2008.12.011] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 12/12/2008] [Accepted: 12/13/2008] [Indexed: 12/31/2022]
Abstract
Angiotensin II (Ang II), the major effector hormone of the renin-angiotensin system (RAS), has an important role in the regulation of vascular and renal homeostasis. Clinical and pharmacological studies have recently shown that Ang II is a critical promoter of insulin resistance and diabetes mellitus type 2. Ang II exerts its actions on insulin-sensitive tissues such as liver, muscle and adipose tissue where it has effects on the insulin receptor (IR), insulin receptor substrate (IRS) proteins and the downstream effectors PI3K, Akt and GLUT4. The molecular mechanisms involved have not been completely identified, but the role of serine/threonine phosphorylation of the IR and IRS-1 proteins in desensitization of insulin action has been well established. The purpose of this review is to highlight recent advances in the understanding of Ang II actions which lead to the development of insulin resistance and its implications for diabetes.
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Affiliation(s)
- J Alberto Olivares-Reyes
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico, DF, Mexico.
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Yang J, Park Y, Zhang H, Xu X, Laine GA, Dellsperger KC, Zhang C. Feed-forward signaling of TNF-alpha and NF-kappaB via IKK-beta pathway contributes to insulin resistance and coronary arteriolar dysfunction in type 2 diabetic mice. Am J Physiol Heart Circ Physiol 2009; 296:H1850-8. [PMID: 19363130 DOI: 10.1152/ajpheart.01199.2008] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We hypothesized that the interaction between tumor necrosis factor-alpha (TNF-alpha)/nuclear factor-kappaB (NF-kappaB) via the activation of IKK-beta may amplify one another, resulting in the evolution of vascular disease and insulin resistance associated with diabetes. To test this hypothesis, endothelium-dependent (ACh) and -independent (sodium nitroprusside) vasodilation of isolated, pressurized coronary arterioles from mLepr(db) (heterozygote, normal), Lepr(db) (homozygote, diabetic), and Lepr(db) mice null for TNF-alpha (db(TNF-)/db(TNF-)) were examined. Although the dilation of vessels to sodium nitroprusside was not different between Lepr(db) and mLepr(db) mice, the dilation to ACh was reduced in Lepr(db) mice. The NF-kappaB antagonist MG-132 or the IKK-beta inhibitor sodium salicylate (NaSal) partially restored nitric oxide-mediated endothelium-dependent coronary arteriolar dilation in Lepr(db) mice, but the responses in mLepr(db) mice were unaffected. The protein expression of IKK-alpha and IKK-beta were higher in Lepr(db) than in mLepr(db) mice; the expression of IKK-beta, but not the expression of IKK-alpha, was attenuated by MG-132, the antioxidant apocynin, or the genetic deletion of TNF-alpha in diabetic mice. Lepr(db) mice showed an increased insulin resistance, but NaSal improved insulin sensitivity. The protein expression of TNF-alpha and NF-kappaB and the protein modification of phosphorylated (p)-IKK-beta and p-JNK were greater in Lepr(db) mice, but NaSal attenuated TNF-alpha, NF-kappaB, p-IKK-beta, and p-JNK in Lepr(db) mice. The ratio of p-insulin receptor substrate (IRS)-1 at Ser307 to IRS-1 was elevated in Lepr(db) compared with mLepr(db) mice; both NaSal and the JNK inhibitor SP-600125 reduced the p-IRS-1-to-IRS-1 ratio in Lepr(db) mice. MG-132 or the neutralization of TNF-alpha reduced superoxide production in Lepr(db) mice. In conclusion, our results indicate that the interaction between NF-kappaB and TNF-alpha signaling induces the activation of IKK-beta and amplifies oxidative stress, leading to endothelial dysfunction in type 2 diabetes.
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Affiliation(s)
- Jiyeon Yang
- Michael E. DeBakey Institute, Texas A&M University, College Station, Texas, USA
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Abstract
Low levels of adiponectin, a fat-derived hormone, are found to be correlated with coronary heart disease, type 2 diabetes, obesity, and insulin resistance. Conversely, high adiponectin levels are predictive of reduced coronary risk in long-term epidemiologic studies. However, the precise role of adiponectin in cardiomyocyte function is still not clear. This study was designed to examine the role of adiponectin in cardiac contractile function in the db/db model of diabetic obesity. Mechanical properties and intracellular Ca(2+) transients were evaluated in cardiomyocytes from lean control and db/db mice with or without adiponectin (10 microg/ml) treatment. Expression and phosphorylation of IRS-1, Akt, c-Jun, and c-Jun N terminal kinase (JNK) as well as markers of endoplasmic reticulum (ER) stress were evaluated using western blotting. Cardiomyocytes from db/db mice exhibited greater cross-sectional area, depressed peak shortening (PS), and maximal velocity of shortening/re-lengthening as well as prolonged duration of re-lengthening. Consistently, myocytes from db/db mice displayed a reduced electrically stimulated rise in intracellular Ca(2+) and prolonged intracellular Ca(2+) decay, which were abrogated by adiponectin treatment. Ratios between phosphorylated c-Jun and c-Jun as well as phosphorylated IRS-1 and IRS-1 were increased in db/db mice, the effect of which was attenuated by adiponectin. Levels of the phosphorylated ER stress makers PERK (Thr980), IRE-1, and eIF2alpha were significantly elevated in db/db mice compared with lean controls, although the effect was unaffected by adiponectin. Collectively, our data suggest that adiponectin improves cardiomyocyte dysfunction in db/db diabetic obese mice through a mechanism possibly related to c-Jun and IRS-1.
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Affiliation(s)
- Feng Dong
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, Wyoming, USA
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Chronic ethanol consumption resulting in the downregulation of insulin receptor-beta subunit, insulin receptor substrate-1, and glucose transporter 4 expression in rat cardiac muscles. Alcohol 2009; 43:51-8. [PMID: 19185210 DOI: 10.1016/j.alcohol.2008.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 10/14/2008] [Accepted: 11/04/2008] [Indexed: 01/10/2023]
Abstract
The objective of this study was to investigate the effect of chronic ethanol intake on the expression of insulin receptor beta subunit (IR-beta), insulin receptor substrate-1 (IRS-1), and glucose transporter 4 (Glut4) in rat cardiac muscle. Forty-eight male Wistar rats were randomly classified into four groups and to each group, ethanol was administered daily at the respective doses of 0 (control, C), 0.5 g kg(-1) (low ethanol, L), 2.5 g kg(-1) (middle ethanol, M), and 5 g kg(-1) (high ethanol, H). Twenty-two weeks later, the rats were anesthetized, and the left ventricle muscles were excised. The IR-beta, IRS-1, and Glut4 mRNA levels in the cardiac muscle tissues were detected by reverse-transcription polymerase chain reaction (RT-PCR); the IR-beta, tyrosine phosphorylation of IR-beta (PY-IR-beta), IRS-1, tyrosine phosphorylation of IRS-1 (PY-IRS-1), and Glut4 protein levels were measured by Western blotting. Compared to the control group, the IR-beta, IRS-1, and Glut4 mRNA levels in groups H and M decreased remarkably. In addition, the protein levels of IR-beta, IRS-1, and Glut4 showed a corresponding decline in ethanol-treated groups, especially in group H. Moreover, the PY-IR-beta and PY-IRS-1 protein levels decreased in the hearts of ethanol-treated rats with corresponding changes in the IR-beta and IRS-1 protein levels. The present study showed that chronic ethanol intake could downregulate the expression levels of IR-beta, IRS-1, and Glut4 in rat cardiac muscles.
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O'Connor JC, McCusker RH, Strle K, Johnson RW, Dantzer R, Kelley KW. Regulation of IGF-I function by proinflammatory cytokines: at the interface of immunology and endocrinology. Cell Immunol 2008; 252:91-110. [PMID: 18325486 DOI: 10.1016/j.cellimm.2007.09.010] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Accepted: 09/01/2007] [Indexed: 11/16/2022]
Abstract
During the past decade, the immune and endocrine systems have been discovered to interact in controlling physiologic processes as diverse as cell growth and differentiation, metabolism, and even human and animal behavior. The interaction between these two major physiological systems is a bi-directional process. While it has been well documented that hormones, including prolactin (PRL), growth hormone (GH), insulin-like growth factor-I (IGF-I), and thyroid-stimulating hormone (TSH), regulate a variety of immune events, a great deal of data have accumulated supporting the notion that cytokines from the innate immune system also affect the neuroendocrine system. Communication between these two systems coordinates processes that are necessary to maintain homeostasis. Proinflammatory cytokines often act as negative regulatory signals that temper the action of hormones and growth factors. This system of 'checks and balances' is an active, ongoing process, even in healthy individuals. Dysregulation of this process has been implicated as a potential pathogenic factor in the development of co-morbid conditions associated with several chronic inflammatory diseases, including type 2 diabetes, cardiovascular disease, cerebrovascular disease, inflammatory bowel disease, rheumatoid arthritis, major depression, and even normal aging. Over the past decade, research in our laboratory has focused on the ability of the major proinflammatory cytokines, tumor necrosis factor (TNF)alpha and interleukin (IL)-1beta, to induce a state of IGF resistance. This review will highlight these and other new findings by explaining how proinflammatory cytokines induce resistance to the major growth factor, insulin-like growth factor-I (IGF-I). We also highlight that IGF-I can induce resistance or reduce sensitivity to brain TNFalpha and discuss how TNFalpha, IL-1beta, and IGF-I interact to regulate several aspects of behavior and cognition.
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Affiliation(s)
- Jason C O'Connor
- Integrative Immunology and Behavior Program, Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Ren J. Interaction between high-fat diet and alcohol dehydrogenase on ethanol-elicited cardiac depression in murine myocytes. Obesity (Silver Spring) 2007; 15:2932-41. [PMID: 18198301 DOI: 10.1038/oby.2007.350] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE Consumption of high-fat diet and alcohol is associated with obesity, leading to enhanced morbidity and mortality. This study was designed to examine the interaction between high-fat diet and the alcohol metabolizing enzyme alcohol dehydrogenase (ADH) on ethanol-induced cardiac depression. RESEARCH METHODS AND PROCEDURES Mechanical and intracellular Ca2+ properties were measured in cardiomyocytes from ADH transgenic and Friend Virus-B type (FVB) mice fed a low- or high-fat diet for 16 weeks. Expression of protein kinase B (Akt) and Foxo3a, two proteins essential for cardiac survival, was evaluated by Western blot. Cardiac damage was determined by carbonyl formation. RESULTS High fat but not ADH induced obesity without hyperglycemia or hypertension, prolonged time-to-90% relengthening (TR90), and depressed peak shortening (PS) and maximal velocity of shortening/relengthening (+/- dL/dt) without affecting intracellular Ca2+ properties. Ethanol suppressed PS and intracellular Ca2+ rise in low-fat-fed FVB mouse cardiomyocytes. ADH but not high-fat diet shifted the threshold of ethanol-induced inhibition of PS and +/- dL/dt to lower levels. The amplitude of ethanol-induced cardiac depression was greater in the high-fat but not the ADH group without additive effects. Ethanol down- and up-regulated Akt and Foxo3a expression, respectively, and depressed intracellular Ca2+ rise, the effects of which were exaggerated by ADH, high-fat, or both. High-fat diet, but not ADH, enhanced Foxo3a expression and carbonyl content in non-ethanol-treated mice. Ethanol challenge significantly enhanced protein carbonyl formation, with the response being augmented by ADH, high-fat, or both. DISCUSSION Our data suggest that high-fat diet and ADH transgene may exaggerate ethanol-induced cardiac depression and protein damage in response to ethanol.
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Affiliation(s)
- Jun Ren
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, 1000 E. University Avenue, Dept. 3375, University of Wyoming, Laramie, WY 82071, USA.
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Song Y, Du Y, Prabhu SD, Epstein PN. Diabetic Cardiomyopathy in OVE26 Mice Shows Mitochondrial ROS Production and Divergence Between In Vivo and In Vitro Contractility. Rev Diabet Stud 2007; 4:159-68. [PMID: 18084673 PMCID: PMC2174063 DOI: 10.1900/rds.2007.4.159] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Many diabetic patients suffer from a cardiomyopathy that cannot be explained solely by poor coronary perfusion. This cardiomyopathy may be due to either organ-based damage like fibrosis, or to direct damage to cardiomyocytes. Mitochondrial-derived reactive oxygen species (ROS) have been proposed to contribute to this cardiomyopathy. To address these questions, we used the OVE26 mouse model of severe type 1 diabetes to measure contractility in isolated cardiomyocytes by edge detection and in vivo with echocardiography. We also assessed the source of ROS generation using both a general and a mitochondrial specific indicator. When contractility was assayed in freshly isolated myocytes, contraction was much stronger in control myocytes. However, contractility of normal myocytes became weaker during 24 hours of in vitro culture. In contrast, contractility of diabetic OVE26 myocytes remains stable during culture. Echocardiography revealed normal or hyperdynamic function in OVE26 hearts under basal conditions but with a sharply reduced response to isoproterenol, a beta-adrenergic agonist. For ROS generation, we found that ROS production in diabetic myocytes was elevated after exposure to either high glucose or angiotensin II (AngII). Superoxide detection with the mitochondrial sensor MitoSOX Red confirmed that mitochondria are a major source of ROS generation in diabetic myocytes. These results show that contractile deficits in OVE26 diabetic hearts are due primarily to cardiomyocyte impairment and that ROS from mitochondria are a cause of that impairment.
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Affiliation(s)
- Ye Song
- Department of Pediatrics, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
| | - Yibo Du
- Department of Pediatrics, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
| | - Sumanth D. Prabhu
- Department of Medicine/Cardiology, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
| | - Paul N. Epstein
- Department of Pediatrics, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
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Dong F, Yang X, Sreejayan N, Ren J. Chromium (D-phenylalanine)3 improves obesity-induced cardiac contractile defect in ob/ob mice. Obesity (Silver Spring) 2007; 15:2699-711. [PMID: 18070761 DOI: 10.1038/oby.2007.322] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Low-molecular weight chromium compounds, such as chromium picolinate [Cr(pic)(3)], improve insulin sensitivity, although toxicity is a concern. We synthesized a novel chromium complex, chromium (d-phenylalanine)(3) [Cr(d-phe)(3)], in an attempt to improve insulin sensitivity with reduced toxicity. The aim of this study was to compare the two chromium compounds on cardiac contractile function in ob/ob obese mice. RESEARCH METHODS AND PROCEDURES C57BL lean and ob/ob obese mice were randomly divided into three groups: H(2)O, Cr(d-phe)(3), or Cr(pic)(3) (45 mug/kg per day orally for 6 months). RESULTS The glucose tolerance test displayed improved glucose clearance by Cr(d-phe)(3) but not Cr(pic)(3). Myocytes from ob/ob mice exhibited depressed peak shortening (PS) and maximal velocity of shortening/relengthening (+/-dL/dt), prolonged time-to-PS and time-to-90% relengthening (TR90), reduced electrically stimulated rise in intracellular Ca(2+) (Deltafura-2 fluorescence intensity), and slowed intracellular Ca(2+) decay. Although a 3-month Cr(d-phe)(3) treatment for a separate group of ob/ob and lean 2-month-old mice only rectified reduced +/-dL/dt in ob/ob mice, all mechanical and intracellular Ca(2+) abnormalities were significantly attenuated or ablated by 6 months of Cr(d-phe)(3) but not Cr(pic)(3) treatment (except TR90). Sarco(endo)plasmic reticulum Ca(2+) ATPase activity and Na(+)-Ca(2+) exchanger expression were depressed in ob/ob mice, which were reversed by both Cr(d-phe)(3) and Cr(pic)(3), with a more pronounced effect from Cr(d-phe)(3). Cr(d-phe)(3) corrected reduced insulin-stimulated glucose uptake and improved basal phosphorylation of Akt and insulin receptor, as well as insulin-stimulated phosphorylation of Akt and insulin receptor in ob/ob myocytes. Heart homogenates from ob/ob mice had enhanced oxidative stress and protein carbonyl formation compared with the lean group, which were attenuated by both Cr(d-phe)(3) and Cr(pic)(3). DISCUSSION Our data suggest that the new Cr(d-phe)(3) compound possesses better cardio-protective and insulin-sensitizing properties against obesity.
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Affiliation(s)
- Feng Dong
- Center for Cardiovascular Research and Alternative Medicine and Division of Pharmaceutical Sciences, University of Wyoming, Laramie, Wyoming 82071, USA
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Dong F, Ren J. Fidarestat improves cardiomyocyte contractile function in db/db diabetic obese mice through a histone deacetylase Sir2-dependent mechanism. J Hypertens 2007; 25:2138-47. [PMID: 17885559 DOI: 10.1097/hjh.0b013e32828626d1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Fidarestat, an aldose reductase (AR) inhibitor, displays promise for the treatment of diabetic neuropathy, although the underlying mechanism of action remains unclear. Histone modification, especially histone acetylation, has been implicated in the pathogenesis of diabetes and its complications. OBJECTIVE The aim of this study was two-fold: to examine the impact of fidarestat on diabetic cardiomyopathy; and to evaluate the role of histone acetylation in the fidarestat-elicited effect, if any. METHODS Cardiomyocytes from db/db diabetic obese and control mice were exposed to fidarestat (0.1-10 mumol/l) for 60 min in the absence or presence of splitomicin, an inhibitor of the NAD-dependent histone deacetylase Sir2. Superoxide levels were measured by dihydroethidium fluorescence. Expression of Sir2, IkappaB (inhibitor of kappaB) and phosphorylated IkappaB was evaluated by western blotting. RESULTS Myocytes from db/db mice exhibited greater cross-sectional area, depressed peak shortening and maximal velocity of shortening/re-lengthening, and prolonged duration of re-lengthening (TR90). Myocytes from db/db mice displayed a reduced rise in intracellular Ca and prolonged intracellular Ca decay. All abnormalities were attenuated by fidarestat. The beneficial effects of fidarestat on db/db cardiomyocytes were nullified by splitomicin with the exception of intracellular Ca decay rate and TR90. Intracellular superoxide was enhanced in db/db myocytes, which was attenuated by fidarestat. Protein expression of Sir2 was decreased in db/db mouse hearts. Phosphorylated IkappaB: IkappaB ratio was increased in db/db mouse. Fidarestat reduced the elevated phosphorylated IkappaB: IkappaB ratio, the effect of which was abolished by splitomicin. CONCLUSIONS Collectively, these results suggest that fidarestat may protect against cardiomyocyte dysfunction in db/db mice through a Sir2-dependent pathway.
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Affiliation(s)
- Feng Dong
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, Wyoming, USA
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Turdi S, Li Q, Lopez FL, Ren J. Catalase alleviates cardiomyocyte dysfunction in diabetes: role of Akt, Forkhead transcriptional factor and silent information regulator 2. Life Sci 2007; 81:895-905. [PMID: 17765928 DOI: 10.1016/j.lfs.2007.07.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 06/07/2007] [Accepted: 07/17/2007] [Indexed: 11/17/2022]
Abstract
Oxidative stress has been speculated to play an essential role in diabetic cardiomyopathy. This study was designed to examine the effect of the antioxidant catalase on diabetes-induced cardiomyocyte dysfunction and the cellular mechanisms involved. Adult wild-type (FVB) and transgenic mice with cardiac-specific overexpression of catalase were made diabetic by a single injection of streptozotocin (STZ, 220 mg/kg; i.p., maintained for two weeks). Cardiomyocyte contractile properties were evaluated including peak shortening (PS), time-to-PS (TPS), time-to-relengthening (TR(90)), maximal velocity of shortening/relengthening (+/-dL/dt), intracellular Ca(2+) level and decay rate. STZ depressed -dL/dt, prolonged TPS and TR(90), elevated resting intracellular Ca(2+) level and reduced intracellular Ca(2+) decay in FVB myocytes. While catalase exhibited little effect on contractile and intracellular Ca(2+) properties in control myocytes, it negated diabetes-induced cardiomyocyte mechanical abnormalities. Diabetic myocytes exhibited enhanced levels of reactive oxygen species and apoptosis, which were alleviated by catalase. Western blot analysis revealed that diabetes reduced Akt phosphorylation, enhanced the silent information regulator 2 (Sirt2), and upregulated Forkhead transcriptional factor Foxo3a as well as glycogen synthase kinase-3beta (GSK-3beta) and pGSK-3beta. While catalase itself exhibited little effect on these proteins or their phosphorylation (with the exception of Sirt2), it significantly attenuated diabetes-induced alteration in pAkt, Foxo3a and Sirt2 without affecting GSK-3beta. Inhibition of Sirt2 using splitomicin impaired cardiomyocyte contractile function (reduced PS, +/-dL/dt, prolonged TPS and TR(90)). In summary, our data suggest potential roles of Akt, Foxo3a and Sirt2 in the onset of diabetic cardiomyopathy and the therapeutic potential of catalase.
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Affiliation(s)
- Subat Turdi
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
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Cooper SA, Whaley-Connell A, Habibi J, Wei Y, Lastra G, Manrique C, Stas S, Sowers JR. Renin-angiotensin-aldosterone system and oxidative stress in cardiovascular insulin resistance. Am J Physiol Heart Circ Physiol 2007; 293:H2009-23. [PMID: 17586614 DOI: 10.1152/ajpheart.00522.2007] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hypertension commonly occurs in conjunction with insulin resistance and other components of the cardiometabolic syndrome. Insulin resistance plays a significant role in the relationship between hypertension, Type 2 diabetes mellitus, chronic kidney disease, and cardiovascular disease. There is accumulating evidence that insulin resistance occurs in cardiovascular and renal tissue as well as in classical metabolic tissues (i.e., skeletal muscle, liver, and adipose tissue). Activation of the renin-angiotensin-aldosterone system and subsequent elevations in angiotensin II and aldosterone, as seen in cardiometabolic syndrome, contribute to altered insulin/IGF-1 signaling pathways and reactive oxygen species formation to induce endothelial dysfunction and cardiovascular disease. This review examines currently understood mechanisms underlying the development of resistance to the metabolic actions of insulin in cardiovascular as well as skeletal muscle tissue.
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Affiliation(s)
- Shawna A Cooper
- Department of Internal Medicine, University of Missouri School of Medicine, Columbia, Missouri 65212, USA
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Relling DP, Esberg LB, Johnson WT, Murphy EJ, Carlson EC, Lukaski HC, Saari JT, Ren J. Dietary interaction of high fat and marginal copper deficiency on cardiac contractile function. Obesity (Silver Spring) 2007; 15:1242-57. [PMID: 17495201 DOI: 10.1038/oby.2007.146] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE High-fat and marginally copper-deficient diets impair heart function, leading to cardiac hypertrophy, increased lipid droplet volume, and compromised contractile function, resembling lipotoxic cardiac dysfunction. However, the combined effect of the two on cardiac function is unknown. This study was designed to examine the interaction between high-fat and marginally copper-deficient diets on cardiomyocyte contractile function. RESEARCH METHODS AND PROCEDURES Weanling male rats were fed diets incorporating a low- or high-fat diet (10% or 45% of kcal from fat, respectively) with adequate (6 mg/kg) or marginally deficient (1.5 mg/kg) copper content for 12 weeks. Contractile function was determined with an IonOptix system including peak shortening (PS), time-to-PS, time-to-90% relengthening, maximal velocity of shortening/relengthening, and intracellular Ca(2+) ([Ca(2+)](I)) rise and decay. RESULTS Neither dietary treatment affected blood pressure or glucose levels, although the high-fat diet elicited obesity and glucose intolerance. Both diets depressed PS, maximal velocity of shortening/relengthening, and intracellular Ca(2+) ([Ca(2+)](I)) rise and prolonged time-to-90% relengthening and Ca(2+) decay without an additive effect between the two. Ca(2+) sensitivity, apoptosis, lipid peroxidation, nitrosative damage, tissue ceramide, and triglyceride levels were unaffected by either diet or in combination. Phospholamban (PLB) but not sarco(endo)plasmic reticulum Ca(2+)-ATPase was increased by both diets. Endothelial NO synthase was depressed with concurrent treatments. The electron transport chain was unaffected, although mitochondrial aconitase activity was inhibited by the high-fat diet. DISCUSSION These data suggest that high-fat and marginally copper deficient diets impaired cardiomyocyte contractile function and [Ca(2+)](i) homeostasis, possibly through a similar mechanism, without obvious lipotoxicity, nitrosative damage, and apoptosis.
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Affiliation(s)
- David P Relling
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine, Grand Forks, North Dakota, USA
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Ouwens DM, Diamant M. Myocardial insulin action and the contribution of insulin resistance to the pathogenesis of diabetic cardiomyopathy. Arch Physiol Biochem 2007; 113:76-86. [PMID: 17558606 DOI: 10.1080/13813450701422633] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heart disease is the leading cause of death in patients with insulin resistance and type 2 diabetes (DM2). Even in the absence of coronary artery disease and hypertension, functional and structural abnormalities exist in patients with well-controlled and uncomplicated DM2. These derangements are collectively designated by the term diabetic cardiomyopathy (DCM). Changes in myocardial energy metabolism, due to altered substrate supply and utilization, largely underlie the development of DCM. Insulin is an important regulator of myocardial substrate metabolism, but also exerts regulatory effects on intracellular Ca2+ handling and cell survival. The current paper reviews the multiple functional and molecular effects of insulin on the heart, all of which ultimately seem to be cardioprotective both under normal conditions and under ischemia. In particular, the dismal consequences of myocardial insulin resistance contributing to the development of DCM will be discussed.
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Affiliation(s)
- D M Ouwens
- Department of Molecular Cell Biology, Leiden University Medical Centre, Leiden, The Netherlands.
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Zakula Z, Koricanac G, Putnikovic B, Markovic L, Isenovic ER. Regulation of the inducible nitric oxide synthase and sodium pump in type 1 diabetes. Med Hypotheses 2007; 69:302-6. [PMID: 17289286 DOI: 10.1016/j.mehy.2006.11.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 11/11/2006] [Indexed: 11/18/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) is a hormone and growth factor closely related to insulin. The autocrine/paracrine actions of IGF-1 involve activation of inducible nitric oxide synthase (iNOS) and the Na(+), K(+)-ATPase sodium pump in cardiovascular tissues. Data from literature indicate that iNOS is expressed in vascular smooth muscle cells (VSMC) and that IGF-1-induced release of NO is both rapid and delayed. We hypothesize that impaired IGF-1-induced sodium pump activity/expression in rats with type 1 diabetes is related to activation of phosphatidylinositol 3 kinase (PI3K)/cytosolic phospholipase 2 (cPLA(2))/protein kinase B (Akt) signaling, and that IGF-1 prevents acute and chronic dysfunction of iNOS and sodium pump activity in a chemically induced model of type 1 diabetes, the streptozotocin-treated rat heart (STZ). Understanding how iNOS and sodium pump activity are regulated by IGF-1 activation of the PI3K/cPLA(2)/Akt cascade should provide novel and fundamental knowledge regarding the regulatory actions of IGF-1 in promoting vasodilation. Since insulin resistance is currently a major focus of research, the use of IGF-1 to improve insulin resistance and glucose metabolism has opened a new arena for treatment of comorbid conditions. Future investigations should now focus on mechanisms of action of IGF-1 and its clinical applicability.
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Affiliation(s)
- Zorica Zakula
- Institute Vinca, Laboratory for Molecular Genetics and Radiobiology, 11000 Belgrade, Serbia and Montenegro
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Wong C, Marwick TH. Alterations in Myocardial Characteristics Associated With Obesity: Detection, Mechanisms, and Implications. Trends Cardiovasc Med 2007; 17:1-5. [PMID: 17210470 DOI: 10.1016/j.tcm.2006.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 04/19/2006] [Accepted: 04/24/2006] [Indexed: 10/23/2022]
Abstract
Hypertension, obstructive sleep apnea, and coronary artery disease all contribute to the myocardial dysfunction in obesity. However, the development of sensitive cardiac imaging techniques has enabled detection of myocardial structural and functional changes independently attributable to obesity, at the preclinical stage. This review will evaluate the evidence for myocardial disease in this setting, its significance, important mechanisms, preclinical detection, and possible therapeutic implications.
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Affiliation(s)
- Chiew Wong
- University of Queensland, Brisbane Qld 4102, Australia
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Fülöp N, Mason MM, Dutta K, Wang P, Davidoff AJ, Marchase RB, Chatham JC. Impact of Type 2 diabetes and aging on cardiomyocyte function and O-linked N-acetylglucosamine levels in the heart. Am J Physiol Cell Physiol 2006; 292:C1370-8. [PMID: 17135297 DOI: 10.1152/ajpcell.00422.2006] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased levels of O-linked attachment of N-acetylglucosamine (O-GlcNAc) on nucleocytoplasmic proteins are implicated in the development of diabetic cardiomyopathy and are regulated by O-GlcNAc transferase (OGT) expression and its substrate UDP-GlcNAc. Therefore, the goal of this study was to determine whether the development of diabetes in the Zucker diabetic fatty (ZDF) rat, a model of Type 2 diabetes, results in defects in cardiomyocyte mechanical function and, if so, whether this is associated with increased levels of O-GlcNAc and increased OGT expression. Six-week-old ZDF rats were hyperinsulinemic but normoglycemic, and there were no differences in cardiomyocyte mechanical function, UDP-GlcNAc, O-GlcNAc, or OGT compared with age-matched lean control rats. Cardiomyocytes isolated from 22-wk-old hyperglycemic ZDF rats exhibited significantly impaired relaxation, compared with both age-matched lean control and 6-wk-old ZDF groups. There was also a significant increase in O-GlcNAc levels in high-molecular-mass proteins in the 22-wk-old ZDF group compared with age-matched lean control and 6-wk-old ZDF groups; this was associated with increased UDP-GlcNAc levels but not increased OGT expression. Surprisingly, there was a significant decrease in overall O-GlcNAc levels between 6 and 22 wk of age in lean, ZDF, and Sprague-Dawley rats that was associated with decreased OGT expression. These results support the notion that an increase in O-GlcNAc on specific proteins may contribute to impaired cardiomyocyte function in diabetes. However, this study also indicates that in the heart the level of O-GlcNAc on proteins appears to be differentially regulated by age and diabetes.
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Affiliation(s)
- Norbert Fülöp
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Toblli JE, Cao G, Rivas C, DeRosa G, Domecq P. Angiotensin-converting enzyme inhibition reduces lipid deposits in myocardium and improves left ventricular function of obese zucker rats. Obesity (Silver Spring) 2006; 14:1586-95. [PMID: 17030970 DOI: 10.1038/oby.2006.183] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Alterations in the renin angiotensin system, cardiac lipotoxicity, and left ventricular (LV) dysfunction have been reported in obese rats. The present study examined whether angiotensin-converting enzyme inhibition could ameliorate lipid deposition and ventricular function in the myocardium of obese Zucker rats (OZRs). RESEARCH METHODS AND PROCEDURES For 6 months, rats were treated as follows: Group (G) 1, OZR, no treatment; G2, OZR + ramipril (R); G3, OZR + amlodipine (AML); and G4, lean Zucker rats. LV function was assessed by echocardiogram and lipid deposits in cardiomyocytes (LDCM) by light microscopy using Oil red O. RESULTS At the end of the experiment, both OZR + R and OZR + AML groups presented similar reduction in blood pressure in comparison with untreated OZR (p < 0.01). OZR with R presented lower insulin-to-glucose ratio and lower serum triglycerides and cholesterol when compared with both untreated OZR and OZR with AML (p < 0.01). Fractional shortening by echocardiogram was as follows: G1, 25.4 +/- 3.8 (vs. G2 and G4, p < 0.05); G2, 37.2 +/- 2.4; G3, 29.3 +/- 4.4 (vs. G2 and G4, p < 0.05); and G4, 40.8 +/- 2.3. Percentage LDCM was as follows: G1, 12.4 +/- 2.7 (vs. G2 and G4, p < 0.05); G2, 0.8 +/- 0.2; G3, 11.1 +/- 2.1 (vs. G2 and G4, p < 0.05); and G4, 0.1 +/- 0.1. There was a negative correlation between fractional shortening and LDCM percentage in OZR (r = -0.93) and in OZR + AML (r = -0.87). DISCUSSION AML reduced blood pressure significantly; however, it failed to modify both metabolic parameters and LDCM. In contrast, R showed a substantial reduction in LDCM, together with LV function preservation.
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Affiliation(s)
- Jorge Eduardo Toblli
- Laboratory of Experimental Medicine, Hospital Alemán, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
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Dong F, Fang CX, Yang X, Zhang X, Lopez FL, Ren J. Cardiac overexpression of catalase rescues cardiac contractile dysfunction induced by insulin resistance: Role of oxidative stress, protein carbonyl formation and insulin sensitivity. Diabetologia 2006; 49:1421-33. [PMID: 16586065 DOI: 10.1007/s00125-006-0230-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 02/10/2006] [Indexed: 10/24/2022]
Abstract
AIMS/HYPOTHESIS Insulin resistance leads to oxidative stress and cardiac dysfunction. This study examined the impact of catalase on insulin-resistance-induced cardiac dysfunction, oxidative damage and insulin sensitivity. METHODS Insulin resistance was initiated in FVB and catalase-transgenic mice by 12 weeks of sucrose feeding. Contractile and intracellular Ca2+ properties were evaluated in cardiomyocytes including peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90), half-width duration (HWD), maximal velocity of shortening/relengthening (+/-dL/dt), fura-fluorescence intensity change (DeltaFFI) and intracellular Ca2+ clearance rate (tau). Reactive oxygen species (ROS) and protein damage were evaluated with dichlorodihydrofluorescein and protein carbonyl formation. RESULTS Sucrose-fed mice displayed hyperinsulinaemia, impaired glucose tolerance and normal body weight. Myocytes from FVB sucrose-fed mice exhibited depressed PS and +/-dL/dt, prolonged TR90 and tau, and reduced DeltaFFI associated with normal TPS and HWD compared with those from starch-fed control mice. ROS and protein carbonyl formation were elevated in FVB sucrose-fed mice. Insulin sensitivity was reduced, evidenced by impaired insulin-stimulated 2-deoxy-D: -[3H]glucose uptake. Western blot analysis indicated that sucrose feeding: (1) inhibited insulin-stimulated phosphorylation of insulin receptor and Akt; (2) enhanced protein-tyrosine phosphatase 1B (PTP1B) expression; and (3) suppressed endothelial nitric oxide synthase (eNOS) and Na+-Ca2+ exchanger expression without affecting peroxisome proliferator-activated receptor gamma (PPARgamma), sarco(endo)plasmic reticulum Ca2+-ATPase isozyme 2a and phospholamban. Catalase ablated insulin-resistance-induced mechanical dysfunction, ROS production and protein damage, and reduced eNOS, but not insulin insensitivity. Catalase itself decreased resting FFI and enhanced expression of PTP1B and PPARgamma. CONCLUSIONS/INTERPRETATION These data indicate that catalase rescues insulin-resistance-induced cardiac dysfunction related to ROS production and protein oxidation but probably does not improve insulin sensitivity.
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Affiliation(s)
- F Dong
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, 1000 E. University Avenue, Department 3375, Laramie, WY 82071, USA
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