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Chen W, Wang J, Wang X, Chang P, Liang M. Knockdown of hypoxia-inducible factor 1-alpha (HIF1α) interferes with angiopoietin-like protein 2 (ANGPTL2) to attenuate high glucose-triggered hypoxia/reoxygenation injury in cardiomyocytes. Bioengineered 2022; 13:1476-1490. [PMID: 34974813 PMCID: PMC8805963 DOI: 10.1080/21655979.2021.2019874] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
To investigate the role of hypoxia-inducible factor 1-alpha (HIF1A) in hypoxia/reoxygenation (H/R) injury of cardiomyocytes induced by high glucose (HG). The in vitro model of coronary heart disease with diabetes was that H9c2 cells were stimulated by H/R and HG. Quantitative reverse transcription PCR (RT-qPCR) and Western blot analysis were used to detect the expression of HIF1A and angiopoietin-like protein 2 (ANGPTL2) in H9c2 cells. Cell viability and apoptosis were, respectively, estimated by Cell Counting Kit 8 (CCK-8) and TUNEL assays. Lactate dehydrogenase (LDH) activity, inflammation and oxidative stress were in turn detected by their commercial assay kits. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were used to confirm the association between HIF1A and ANGPTL2 promoter. The expression of nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway-related proteins and apoptosis-related proteins were also detected by Western blot analysis. As a result, ANGPTL2 expression was upregulated in H9c2 cells induced by HG or/and H/R. ANGPTL2 positively modulated HIF1A expression in H9c2 cells. HG or/and H/R suppressed the cell viability and promoted apoptosis, inflammatory response and oxidative stress levels in H9c2 cells. However, the knockdown of ANGPTL2 could reverse the above phenomena in H/R-stimulated-H9c2 cells through activation of Nrf2/HO-1 pathway. HIF1A transcriptionally activated ANGPTL2 expression. The effect of knockdown of ANGPTL2 on H/R triggered-H9c2 cells was weakened by HIF1A overexpression. In conclusion, knockdown of HIF1A downregulated ANGPTL2 to alleviate H/R injury in HG-induced H9c2 cells by activating the Nrf2/HO-1 pathway.
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Affiliation(s)
- Weiguo Chen
- Department of Cardiology, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, P.R. China
| | - Jianbang Wang
- Department of Cardiology, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, P.R. China
| | - Xihui Wang
- Department of Cardiology, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, P.R. China
| | - Pan Chang
- Experimental Center, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, P.R. China
| | - Meng Liang
- Department of Cardiology, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, P.R. China
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The role of CD36 in the regulation of myocardial lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1450-60. [DOI: 10.1016/j.bbalip.2016.03.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/12/2016] [Accepted: 03/14/2016] [Indexed: 12/29/2022]
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Zhang Z, Wang S, Zhou S, Yan X, Wang Y, Chen J, Mellen N, Kong M, Gu J, Tan Y, Zheng Y, Cai L. Sulforaphane prevents the development of cardiomyopathy in type 2 diabetic mice probably by reversing oxidative stress-induced inhibition of LKB1/AMPK pathway. J Mol Cell Cardiol 2014; 77:42-52. [PMID: 25268649 DOI: 10.1016/j.yjmcc.2014.09.022] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/28/2014] [Accepted: 09/18/2014] [Indexed: 12/22/2022]
Abstract
Type 2 diabetes mellitus (T2DM)-induced cardiomyopathy is associated with cardiac oxidative stress, inflammation, and remodeling. Sulforaphane (SFN), an isothiocyanate naturally presenting in widely consumed vegetables, particularly broccoli, plays an important role in cardiac protection from diabetes. We investigated the effect of SFN on T2DM-induced cardiac lipid accumulation and subsequent cardiomyopathy. Male C57BL/6J mice were fed a high-fat diet for 3months to induce insulin resistance, followed by a treatment with 100mg/kg body-weight streptozotocin to induce hyperglycemia; we referred to it as the T2DM mouse model. Other age-matched mice were fed a normal diet as control. T2DM and control mice were treated with or without 4-month SFN at 0.5mg/kg daily five days a week. At the study's end, cardiac function was assessed. SFN treatment significantly attenuated cardiac remodeling and dysfunction induced by T2DM. SFN treatment also significantly inhibited cardiac lipid accumulation, measured by Oil Red O staining, and improved cardiac inflammation oxidative stress and fibrosis, shown by down-regulating diabetes-induced PAI-1, TNF-α, CTGF, TGF-β, 3-NT, and 4-HNE expression. Elevated 4-HNE resulted in the increase of 4-HNE-LKB1 adducts that should inhibit LKB1 and subsequent AMPK activity. SFN upregulated the expression of Nrf2 and its downstream genes, NQO1 and HO-1, decreased 4-HNE-LKB1 adducts and then reversed diabetes-induced inhibition of LKB1/AMPK and its downstream targets, including sirtuin 1, PGC-1α, phosphorylated acetyl-CoA carboxylase, carnitine palmitoyl transferase-1, ULK1, and light chain-3 II. These results suggest that SFN treatment to T2DM mice may attenuate the cardiac oxidative stress-induced inhibition of LKB1/AMPK signaling pathway, thereby preventing T2DM-induced lipotoxicity and cardiomyopathy.
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Affiliation(s)
- Zhiguo Zhang
- Department of Cardiology at the First Hospital of Jilin University, Changchun 130021, China; Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA
| | - Shudong Wang
- Department of Cardiology at the First Hospital of Jilin University, Changchun 130021, China; Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA
| | - Shanshan Zhou
- Department of Cardiology at the First Hospital of Jilin University, Changchun 130021, China; Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA
| | - Xiaoqing Yan
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA; The Chinese-American Research Institute for Diabetic Complications, Wenzhou Medical University, Wenzhou 325035, China
| | - Yonggang Wang
- Department of Cardiology at the First Hospital of Jilin University, Changchun 130021, China; Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA
| | - Jing Chen
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA
| | - Nicholas Mellen
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA
| | - Maiying Kong
- Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY 40202, USA
| | - Junlian Gu
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA; Department of Pathology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan 250014, China
| | - Yi Tan
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA; The Chinese-American Research Institute for Diabetic Complications, Wenzhou Medical University, Wenzhou 325035, China
| | - Yang Zheng
- Department of Cardiology at the First Hospital of Jilin University, Changchun 130021, China.
| | - Lu Cai
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville 40202, USA; The Chinese-American Research Institute for Diabetic Complications, Wenzhou Medical University, Wenzhou 325035, China.
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Zhang D, Wan A, Chiu APL, Wang Y, Wang F, Neumaier K, Lal N, Bround MJ, Johnson JD, Vlodavsky I, Rodrigues B. Hyperglycemia-induced secretion of endothelial heparanase stimulates a vascular endothelial growth factor autocrine network in cardiomyocytes that promotes recruitment of lipoprotein lipase. Arterioscler Thromb Vasc Biol 2013; 33:2830-8. [PMID: 24115032 DOI: 10.1161/atvbaha.113.302222] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE During diabetes mellitus, coronary lipoprotein lipase increases to promote the predominant use of fatty acids. We have reported that high glucose stimulates active heparanase secretion from endothelial cells to cleave cardiomyocyte heparan sulfate and release bound lipoprotein lipase for transfer to the vascular lumen. In the current study, we examined whether heparanase also has a function to release cardiomyocyte vascular endothelial growth factor (VEGF), and whether this growth factor influences cardiomyocyte fatty acid delivery in an autocrine manner. APPROACH AND RESULTS Acute, reversible hyperglycemia was induced in rats, and a modified Langendorff heart perfusion was used to separate the coronary perfusate from the interstitial effluent. Coronary artery endothelial cells were exposed to high glucose to generate conditioned medium, and VEGF release from isolated cardiomyocytes was tested using endothelial cell conditioned medium or purified active and latent heparanase. Autocrine signaling of myocyte-derived VEGF on cardiac metabolism was studied. High glucose promoted latent and active heparanase secretion into endothelial cell conditioned medium, an effective stimulus for releasing cardiomyocyte VEGF. Intriguingly, latent heparanase was more efficient than active heparanase in releasing VEGF from a unique cell surface pool. VEGF augmented cardiomyocyte intracellular calcium and AMP-activated protein kinase phosphorylation and increased heparin-releasable lipoprotein lipase. CONCLUSIONS Our data suggest that the heparanase-lipoprotein lipase-VEGF axis amplifies fatty acid delivery, a rapid and adaptive mechanism that is geared to overcome the loss of glucose consumption by the diabetic heart. If prolonged, the resultant lipotoxicity could lead to cardiovascular disease in humans.
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Affiliation(s)
- Dahai Zhang
- From the Faculty of Pharmaceutical Sciences (D.Z., A.W., A.P.-L.C., Y.W., F.W., K.N., N.L., B.R.), and Department of Cellular and Physiological Sciences (M.J.B., J.D.J.), University of British Columbia, Canada; and Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Israel (I.V.)
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Pulinilkunnil T, Kienesberger PC, Nagendran J, Waller TJ, Young ME, Kershaw EE, Korbutt G, Haemmerle G, Zechner R, Dyck JR. Myocardial adipose triglyceride lipase overexpression protects diabetic mice from the development of lipotoxic cardiomyopathy. Diabetes 2013; 62:1464-77. [PMID: 23349479 PMCID: PMC3636613 DOI: 10.2337/db12-0927] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although diabetic cardiomyopathy is associated with enhanced intramyocardial triacylglycerol (TAG) levels, the role of TAG catabolizing enzymes in this process is unclear. Because the TAG hydrolase, adipose triglyceride lipase (ATGL), regulates baseline cardiac metabolism and function, we examined whether alterations in cardiomyocyte ATGL impact cardiac function during uncontrolled type 1 diabetes. In genetic (Akita) and pharmacological (streptozotocin) murine models of type 1 diabetes, cardiac ATGL protein expression and TAG content were significantly increased. To determine whether increased ATGL expression during diabetes is detrimental or beneficial to cardiac function, we studied streptozotocin-diabetic mice with heterozygous ATGL deficiency and cardiomyocyte-specific ATGL overexpression. After diabetes, streptozotocin-diabetic mice with heterozygous ATGL deficiency displayed increased TAG accumulation, lipotoxicity, and diastolic dysfunction comparable to wild-type mice. In contrast, myosin heavy chain promoter (MHC)-ATGL mice were resistant to diabetes-induced increases in intramyocardial TAG levels, lipotoxicity, and cardiac dysfunction. Moreover, hearts from diabetic MHC-ATGL mice exhibited decreased reliance on palmitate oxidation and blunted peroxisome proliferator--activated receptor-α activation. Collectively, this study shows that after diabetes, increased cardiac ATGL expression is an adaptive, albeit insufficient, response to compensate for the accumulation of myocardial TAG, and that overexpression of ATGL is sufficient to ameliorate diabetes-induced cardiomyopathy.
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Affiliation(s)
- Thomas Pulinilkunnil
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Petra C. Kienesberger
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jeevan Nagendran
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Terri J. Waller
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Martin E. Young
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Erin E. Kershaw
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gregory Korbutt
- Alberta Diabetes Institute and Cardiovascular Research Centre, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Jason R.B. Dyck
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Corresponding author: Jason R.B. Dyck,
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Kim MS, Wang Y, Rodrigues B. Lipoprotein lipase mediated fatty acid delivery and its impact in diabetic cardiomyopathy. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:800-8. [PMID: 22024251 DOI: 10.1016/j.bbalip.2011.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 09/15/2011] [Accepted: 10/03/2011] [Indexed: 01/29/2023]
Abstract
Although cardiovascular disease is the leading cause of diabetes-related death, its etiology is still not understood. The immediate change that occurs in the diabetic heart is altered energy metabolism where in the presence of impaired glucose uptake, glycolysis, and pyruvate oxidation, the heart switches to exclusively using fatty acids (FA) for energy supply. It does this by rapidly amplifying its lipoprotein lipase (LPL-a key enzyme, which hydrolyzes circulating lipoprotein-triglyceride to release FA) activity at the coronary lumen. An abnormally high capillary LPL could provide excess fats to the heart, leading to a number of metabolic, morphological, and mechanical changes, and eventually to cardiac disease. Unlike the initial response, chronic severe diabetes "turns off" LPL, this is also detrimental to cardiac function. In this review, we describe a number of post-translational mechanisms that influence LPL vesicle formation, actin cytoskeleton rearrangement, and transfer of LPL from cardiomyocytes to the vascular lumen to hydrolyze lipoprotein-triglyceride following diabetes. Appreciating the mechanism of how the heart regulates its LPL following diabetes should allow the identification of novel targets for therapeutic intervention, to prevent heart failure. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Min Suk Kim
- Molecular and Cellular Pharmacology, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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Kilmer G, Hughes E, Zhang X, Elam-Evans L. Diabetes and prediabetes: screening and prevalence among adults with coronary heart disease. Am J Prev Med 2011; 40:159-65. [PMID: 21238864 DOI: 10.1016/j.amepre.2010.09.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 06/21/2010] [Accepted: 09/03/2010] [Indexed: 11/25/2022]
Abstract
BACKGROUND Clinical performance measures recommend that nondiabetic patients with coronary heart disease (CHD) be screened for diabetes every 3 years. PURPOSE The purpose of this study is to report the prevalence of diabetes and prediabetes among U.S. adults aged ≥35 years with CHD and to determine factors associated with not receiving recommended diabetes screenings. METHODS The Behavioral Risk Factor Surveillance System (BRFSS) is an annual state-based telephone survey of non-institutionalized U.S. adults. Information on prediabetes prevalence was collected for 33 states in 2008; data analysis was conducted in 2009. The prevalence of diabetes and prediabetes among adults aged ≥35 years with CHD (n=20,618) and prevalence of diabetes screening among nondiabetic adults with CHD (n=14,335) were assessed. Multivariate logistic regression was used to calculate the odds of not being screened for diabetes in the past 3 years while controlling for other factors. RESULTS Among adults with CHD, 30.7% (95% CI=29.4%, 32.1%) reported being diagnosed with diabetes and 10.0% (95% CI=9.2%, 10.8%) reported prediabetes. Among nondiabetic adults with CHD, 25.4% (95% CI=23.9%, 26.9%) reported not being screened for diabetes in the past 3 years. Those with no recent routine checkup and those with no health insurance had the highest odds of no recent diabetes screening. CONCLUSIONS The prevalence of diabetes and prediabetes is substantial among adults with CHD and likely underestimated because of suboptimal screening. One of four nondiabetic adults with CHD reported not being screened for diabetes in the past 3 years.
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Resl M, Hülsmann M, Pacher R, Clodi M. [Heart failure in diabetes]. Wien Med Wochenschr 2009; 159:134-40. [PMID: 19343290 DOI: 10.1007/s10354-009-0645-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 10/03/2008] [Indexed: 01/01/2023]
Abstract
Interactions of glucose metabolism and chronic heart failure have been confirmed by many epidemiologic studies. The association of HbA1c with an increasing risk of heart failure clearly underlines the connection between both diseases. Coronary artery disease (CAD), hypertension and diabetic cardiomyopathy are long-term complications of diabetes mellitus, resulting in diabetic heart failure. Dysfunction of many regulation systems leads to specific diabetic cardiomyopathy, which has been firstly described by Rubler. A reduction in the cardiac expression of the Na-Ca exchanger pump and SERCA2a protein results in an imbalance in cardiac calcium handling. The overactive renin angiotensin aldosteron system (RAAS) also contributes to the impairment of myocardial function. Hyperlipidaemia, hpyerinsulinaemia and hyperglycaemia directly trigger diabetic cardiomyopathy. Generally chronic heart failure is a clinical diagnosis verified by blood tests like NT-proBNP and cardiac ultrasound. Recommendations on treatment of diabetic heart failure are based on subgroup analysis of the large heart failure trials.
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Affiliation(s)
- Michael Resl
- Klinische Abteilung für Endokrinologie und Stoffwechsel, Universitätsklinik für Innere Medizin III, Medizinische Universität Wien, Wien, Austria
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9
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Berry C, Tardif JC, Bourassa MG. Coronary Heart Disease in Patients With Diabetes. J Am Coll Cardiol 2007; 49:631-42. [PMID: 17291928 DOI: 10.1016/j.jacc.2006.09.046] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 09/07/2006] [Accepted: 09/11/2006] [Indexed: 12/25/2022]
Abstract
Diabetes mellitus (DM) is a worldwide epidemic. Its prevalence is rapidly increasing in both developing and developed countries. Coronary heart disease (CHD) is highly prevalent and is the major cause of morbidity and mortality in diabetic patients. The purpose of this review is to assess the clinical impact of recent advances in the epidemiology, prevention, and management of CHD in diabetic patients. A systematic review of publications in this area, referenced in MEDLINE in the past 5 years (2000 to 2005), was undertaken. Patients with CHD and prediabetic states should undergo lifestyle modifications aimed at preventing DM. Pharmacological prevention of DM is also promising but requires further study. In patients with CHD and DM, routine use of aspirin and an angiotensin-converting enzyme inhibitor (ACE-I)--unless contraindicated or not tolerated-and strict glycemic, blood pressure, and lipid control are strongly recommended. The targets for secondary prevention in these patients are relatively well defined, but the strategies to achieve them vary and must be individualized. Intense insulin therapy might be needed for glycemic control, and high-dose statin therapy might be needed for lipid control. For blood pressure control, ACE-Is and angiotensin receptor blockers are considered as first-line therapy. Noncompliance, particularly with lifestyle measures, and underprescription of evidence-based therapies remain important unsolved problems.
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Affiliation(s)
- Colin Berry
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada
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An D, Kewalramani G, Chan JKY, Qi D, Ghosh S, Pulinilkunnil T, Abrahani A, Innis SM, Rodrigues B. Metformin influences cardiomyocyte cell death by pathways that are dependent and independent of caspase-3. Diabetologia 2006; 49:2174-84. [PMID: 16868748 DOI: 10.1007/s00125-006-0338-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Accepted: 05/10/2006] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Metformin has been shown to increase fatty acid oxidation, an effect mediated by AMP activated protein kinase (AMPK). We hypothesised that metformin could prevent both caspase-3 activation and apoptosis when induced by palmitic acid. MATERIALS AND METHODS Cardiomyocytes were incubated with 1 mmol/l palmitic acid, in the absence or presence of metformin (1-5 mmol/l). Following 1 to 16 h, cell damage was evaluated by measuring lactate dehydrogenase released into the incubation medium, and Hoechst staining. To investigate the mechanism of metformin's effect on cardiomyocytes, substrate utilisation and phosphorylation of AMPK and acetyl-CoA carboxylase were measured. Intracellular mediators of apoptosis were also evaluated. RESULTS Incubation of myocytes with palmitic acid for 16 h increased apoptosis, an effect that was partly blunted by 1 and 2 mmol/l metformin. This beneficial effect of metformin was associated with increased AMPK phosphorylation, palmitic acid oxidation and suppression of high-fat-induced increases in (1) long chain base biosynthesis protein 1 levels, (2) ceramide levels, and (3) caspase-3 activity. Unexpectedly, 5 mmol/l metformin dramatically increased apoptosis in myocytes incubated with high fat. This effect was associated with a robust increase in glycolysis, lactate accumulation, and a significant drop of pH in the myocyte incubation medium. CONCLUSIONS/INTERPRETATION Our study demonstrates that metformin reduces high-fat-induced cardiac cell death, probably through inhibition of ceramide synthesis. However, at high concentrations, metformin causes proton and lactate accumulation, leading to cell damage that is independent of caspase-3.
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Affiliation(s)
- D An
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The University of British Columbia, 2146 East Mall, Vancouver, BC, Canada, V6T 1Z3
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An D, Rodrigues B. Role of changes in cardiac metabolism in development of diabetic cardiomyopathy. Am J Physiol Heart Circ Physiol 2006; 291:H1489-506. [PMID: 16751293 DOI: 10.1152/ajpheart.00278.2006] [Citation(s) in RCA: 329] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In patients with diabetes, an increased risk of symptomatic heart failure usually develops in the presence of hypertension or ischemic heart disease. However, a predisposition to heart failure might also reflect the effects of underlying abnormalities in diastolic function that can occur in asymptomatic patients with diabetes alone (termed diabetic cardiomyopathy). Evidence of cardiomyopathy has also been demonstrated in animal models of both Type 1 (streptozotocin-induced diabetes) and Type 2 diabetes (Zucker diabetic fatty rats and ob/ob or db/db mice). During insulin resistance or diabetes, the heart rapidly modifies its energy metabolism, resulting in augmented fatty acid and decreased glucose consumption. Accumulating evidence suggests that this alteration of cardiac metabolism plays an important role in the development of cardiomyopathy. Hence, a better understanding of this dysregulation in cardiac substrate utilization during insulin resistance and diabetes could provide information as to potential targets for the treatment of cardiomyopathy. This review is focused on evaluating the acute and chronic regulation and dysregulation of cardiac metabolism in normal and insulin-resistant/diabetic hearts and how these changes could contribute toward the development of cardiomyopathy.
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MESH Headings
- Animals
- Cardiomyopathies/etiology
- Cardiomyopathies/metabolism
- Cardiomyopathies/pathology
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/pathology
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Disease Models, Animal
- Energy Metabolism/physiology
- Fatty Acids/metabolism
- Glucose/metabolism
- Humans
- Insulin Resistance/physiology
- Mice
- Mice, Obese
- Myocardium/metabolism
- Myocardium/pathology
- Rats
- Rats, Zucker
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Affiliation(s)
- Ding An
- Div. of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The Univ. of British Columbia, 2146 East Mall, Vancouver, BC, Canada
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12
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Abstract
Diabetes mellitus is a worldwide epidemic. Cardiovascular disease remains the major cause of morbidity and mortality in people with diabetes. Studies have suggested that increased risk of cardiovascular disease is not restricted to type II or type I diabetes mellitus, but extends to prediabetic stages such as impaired fasting glucose, impaired glucose tolerance, metabolic syndrome, and obesity. Insulin resistance, impaired fasting glucose, impaired glucose tolerance, and diabetes mellitus form a continuous sequence of risk for cardiovascular disease. Therefore, cardiovascular disease mortality and morbidity within the diabetes epidemic grow into vast proportions. Evidence also exists that diabetic patients have a high prevalence of heart failure or impaired diastolic and systolic cardiac function subsequent to the combination of coronary artery disease, hypertension, and diabetic cardiomyopathy. In view of the proportions of this new epidemic, prevention of diabetes and its prediabetic states is likely to be the most effective strategy to prevent serious cardiovascular events.
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Affiliation(s)
- Dimitrios N Tziakas
- University Cardiology Department, Democritus University of Thrace, Alexandroupolis, Greece
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Jack L. Beyond lifestyle interventions in diabetes: a rationale for public and economic policies to intervene on social determinants of health. JOURNAL OF PUBLIC HEALTH MANAGEMENT AND PRACTICE 2005; 11:357-60. [PMID: 15958937 DOI: 10.1097/00124784-200507000-00016] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Leonard Jack
- Department of Community Health and Preventive Medicine, Morehouse School of Medicine, 720 Westview Drive, Atlanta, GA 30310, USA.
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Wang PS, Avorn J, Brookhart MA, Mogun H, Schneeweiss S, Fischer MA, Glynn RJ. Effects of noncardiovascular comorbidities on antihypertensive use in elderly hypertensives. Hypertension 2005; 46:273-9. [PMID: 15983239 DOI: 10.1161/01.hyp.0000172753.96583.e1] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although the benefits of antihypertensive drugs have been clearly established, they remain underused by vulnerable older populations. We examined whether the presence of noncardiovascular comorbidity deters use of antihypertensives in elderly with hypertension. We conducted a retrospective cohort study among 51,517 patients > or =65 years of age in the Pennsylvania Pharmaceutical Assistance Contract for the Elderly (PACE) Program during 1999 and 2000. All were hypertensive and had diagnoses and used treatments during 1999 to qualify for entry into 1 of the following 5 mutually exclusive cohorts: asthma/chronic obstructive pulmonary disease (COPD), depression, gastrointestinal (GI) disorders, osteoarthritis, or none of the 4 comorbidities. Proportions using antihypertensives in 2000 were assessed. Logistic regression analysis was used to identify the independent effects on antihypertensive use of the 4 comorbidities of interest, sociodemographic characteristics, other cardiovascular and noncardiovascular comorbidity, and health care utilization variables. After adjustments in multivariable analyses, antihypertensive use was consistently lower in patients with asthma/COPD (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.40 to 0.47), depression (OR, 0.50; 95% CI, 0.45 to 0.55), GI disorders (OR, 0.59; 95% CI, 0.54 to 0.64), and osteoarthritis (OR, 0.63; 95% CI, 0.59 to 0.67) relative to those without these conditions. Reduced antihypertensive use was also associated with older age, female gender, white race, more severe other comorbidities, absence of some cardiovascular indications, hospitalizations, nursing home care, physician visits, and use of fewer other medications. Highly prevalent, noncardiovascular conditions appear to deter use of antihypertensives in elderly with hypertension.
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Affiliation(s)
- Philip S Wang
- Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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Pulinilkunnil T, An D, Ghosh S, Qi D, Kewalramani G, Yuen G, Virk N, Abrahani A, Rodrigues B. Lysophosphatidic acid-mediated augmentation of cardiomyocyte lipoprotein lipase involves actin cytoskeleton reorganization. Am J Physiol Heart Circ Physiol 2005; 288:H2802-10. [PMID: 15681706 DOI: 10.1152/ajpheart.01162.2004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The lipoprotein lipase (LPL)-augmenting property of lysophosphatidylcholine requires the formation of lysophosphatidic acid (LPA) (J Mol Cell Cardiol 37: 931-938, 2004). Given that the actin cytoskeleton has been implicated in regulating cardiomyocyte LPL, we examined whether LPL secretion after LPA involves actin cytoskeleton reassembly. Incubation of myocytes with LPA (1-100 nM) increased basal and heparin-releasable LPL (HR-LPL), an effect that was independent of shifts in LPL mRNA. The influence of LPA on myocyte LPL was reflected at the coronary lumen, with substantial increases of the enzyme at this location. Incubation of myocytes with cytochalasin D not only blocked LPA-induced augmentation of HR-LPL but also abrogated filamentous actin formation. These effects of LPA were likely receptor mediated. Exposure of myocytes to LPA facilitated significant membrane translocation of RhoA and its downstream effector Rho kinase I (ROCK I), and blocking this effect with Y-27632 appreciably reduced basal and HR-LPL activity. Incubation of adipose tissue with LPA also significantly enhanced basal and HR-LPL activity, suggesting that sarcomeric actin likely has a limited role in influencing the LPL secretory function of LPA in the myocyte. Comparable to LPA, hyperglycemia also caused significant membrane translocation of RhoA and ROCK I in hearts isolated from diazoxide-treated animals, effects that were abrogated using insulin. Overall, our data suggest that comparable to hyperglycemia, LPA-induced increases in cardiac LPL occurred via posttranscriptional mechanisms and processes that likely required RhoA activation and actin polymerization. Whether this increase in LPL augments triglyceride deposition in the heart leading to eventual impairment in contractile function is currently unknown.
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Affiliation(s)
- Thomas Pulinilkunnil
- Div. of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The Univ. of British Columbia, 2146 East Mall, Vancouver, British Columbia, Canada.
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