1
|
Lee SY, Lee TW, Park GT, Kim JH, Lee HC, Han JH, Yoon A, Yoon D, Kim S, Jung SM, Choi JH, Chon MK, Lee SH, Hwang KW, Kim J, Park YH, Kim JH, Chun KJ, Hur J. Sodium/glucose Co-Transporter 2 Inhibitor, Empagliflozin, Alleviated Transient Expression of SGLT2 after Myocardial Infarction. Korean Circ J 2021; 51:251-262. [PMID: 33655725 PMCID: PMC7925966 DOI: 10.4070/kcj.2020.0303] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 01/10/2023] Open
Abstract
Background and Objectives Large clinical studies of sodium/glucose cotransporter 2 (SGLT2) inhibitors have shown a significant beneficial effect on heart failure-associated hospitalization and cardiovascular events. As SGLT2 is known to be absent in heart cells, improved cardiovascular outcomes are thought to be accounted for by the indirect effects of the drug. We sought to confirm whether such benefits were mediated through SGLT2 expressed in the heart using myocardial infarction (MI) model. Methods Mice pre-treated with empagliflozin (EMPA), an SGLT2 inhibitor, showed a significantly reduced infarct size compared with the vehicle group three days post-MI. Interestingly, we confirmed SGLT2 localized in the infarct zone. The sequential changes of SGLT2 expression after MI were also evaluated. Results One day after MI, SGLT2 transiently appeared in the ischemic areas in the vehicle group and increased until 72 hours. The appearance of SGLT2 was delayed and less in amount compared with the vehicle group. Additionally, there was a significant difference in metabolites, including glucose and amino acids in the 1H nuclear magnetic resonance analysis between groups. Conclusions Our work demonstrates that SGLT2 is transiently expressed in heart tissue early after MI and EMPA may directly operate on SGLT2 to facilitate metabolic substrates shifts.
Collapse
Affiliation(s)
- Soo Yong Lee
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea.,Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Tae Wook Lee
- Department of Physiology, School of Medicine, Pusan National University, Yangsan, Korea
| | - Gyu Tae Park
- Department of Physiology, School of Medicine, Pusan National University, Yangsan, Korea
| | - Jae Ho Kim
- Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea.,Department of Physiology, School of Medicine, Pusan National University, Yangsan, Korea
| | - Hyun Chae Lee
- Department of Convergence Medicine, Pusan National University School of Medicine, Yangsan, Korea
| | - Jung Hwa Han
- Department of Convergence Medicine, Pusan National University School of Medicine, Yangsan, Korea.,PNU GRAND Convergence Medical Science Education Research Center, Pusan National University School of Medicine, Yangsan, Korea
| | - Aeseon Yoon
- Department of Convergence Medicine, Pusan National University School of Medicine, Yangsan, Korea.,PNU GRAND Convergence Medical Science Education Research Center, Pusan National University School of Medicine, Yangsan, Korea
| | - Dahye Yoon
- Department of Chemistry, Center for Proteome Biophysics and Chemistry Institute for Functional Materials, Pusan National University, Busan, Korea
| | - Shukmann Kim
- Department of Chemistry, Center for Proteome Biophysics and Chemistry Institute for Functional Materials, Pusan National University, Busan, Korea
| | - Soon Myung Jung
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jin Hee Choi
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Min Ku Chon
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Sang Hyun Lee
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Ki Won Hwang
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jeongsu Kim
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Yong Hyun Park
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - June Hong Kim
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Kook Jin Chun
- Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jin Hur
- Department of Convergence Medicine, Pusan National University School of Medicine, Yangsan, Korea.,PNU GRAND Convergence Medical Science Education Research Center, Pusan National University School of Medicine, Yangsan, Korea.
| |
Collapse
|
2
|
Andres DA, Young LEA, Veeranki S, Hawkinson TR, Levitan BM, He D, Wang C, Satin J, Sun RC. Improved workflow for mass spectrometry-based metabolomics analysis of the heart. J Biol Chem 2020; 295:2676-2686. [PMID: 31980460 DOI: 10.1074/jbc.ra119.011081] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/17/2020] [Indexed: 01/08/2023] Open
Abstract
MS-based metabolomics methods are powerful techniques to map the complex and interconnected metabolic pathways of the heart; however, normalization of metabolite abundance to sample input in heart tissues remains a technical challenge. Herein, we describe an improved GC-MS-based metabolomics workflow that uses insoluble protein-derived glutamate for the normalization of metabolites within each sample and includes normalization to protein-derived amino acids to reduce biological variation and detect small metabolic changes. Moreover, glycogen is measured within the metabolomics workflow. We applied this workflow to study heart metabolism by first comparing two different methods of heart removal: the Langendorff heart method (reverse aortic perfusion) and in situ freezing of mouse heart with a modified tissue freeze-clamp approach. We then used the in situ freezing method to study the effects of acute β-adrenergic receptor stimulation (through isoproterenol (ISO) treatment) on heart metabolism. Using our workflow and within minutes, ISO reduced the levels of metabolites involved in glycogen metabolism, glycolysis, and the Krebs cycle, but the levels of pentose phosphate pathway metabolites and of many free amino acids remained unchanged. This observation was coupled to a 6-fold increase in phosphorylated adenosine nucleotide abundance. These results support the notion that ISO acutely accelerates oxidative metabolism of glucose to meet the ATP demand required to support increased heart rate and cardiac output. In summary, our MS-based metabolomics workflow enables improved quantification of cardiac metabolites and may also be compatible with other methods such as LC or capillary electrophoresis.
Collapse
Affiliation(s)
- Douglas A Andres
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky 40536; Gill Heart and Vascular Institute, University of Kentucky College of Medicine, Lexington, Kentucky 40536; Spinal Cord and Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, Kentucky 40536; Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Lyndsay E A Young
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Sudhakar Veeranki
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky 40536; Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Tara R Hawkinson
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky 40536
| | - Bryana M Levitan
- Gill Heart and Vascular Institute, University of Kentucky College of Medicine, Lexington, Kentucky 40536; Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Daheng He
- Department of Biostatistics, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Chi Wang
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky 40536; Department of Biostatistics, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Jonathan Satin
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Ramon C Sun
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky 40536; Department of Neuroscience, University of Kentucky, Lexington, Kentucky 40536.
| |
Collapse
|
3
|
Daniels LJ, Varma U, Annandale M, Chan E, Mellor KM, Delbridge LMD. Myocardial Energy Stress, Autophagy Induction, and Cardiomyocyte Functional Responses. Antioxid Redox Signal 2019; 31:472-486. [PMID: 30417655 DOI: 10.1089/ars.2018.7650] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Significance: Energy stress in the myocardium occurs in a variety of acute and chronic pathophysiological contexts, including ischemia, nutrient deprivation, and diabetic disease settings of substrate disturbance. Although the heart is highly adaptive and flexible in relation to fuel utilization and routes of adenosine-5'-triphosphate (ATP) generation, maladaptations in energy stress situations confer functional deficit. An understanding of the mechanisms that link energy stress to impaired myocardial performance is crucial. Recent Advances: Emerging evidence suggests that, in parallel with regulated enzymatic pathways that control intracellular substrate supply, other processes of "bulk" autophagic macromolecular breakdown may be important in energy stress conditions. Recent findings indicate that cargo-specific autophagic activity may be important in different stress states. In particular, induction of glycophagy, a glycogen-specific autophagy, has been described in acute and chronic energy stress situations. The impact of elevated cardiomyocyte glucose flux relating to glycophagy dysregulation on contractile function is unknown. Critical Issues: Ischemia- and diabetes-related cardiac adverse events comprise the majority of cardiovascular disease morbidity and mortality. Current therapies involve management of systemic comorbidities. Cardiac-specific adjunct treatments targeted to manage myocardial energy stress responses are lacking. Future Directions: New knowledge is required to understand the mechanisms involved in selective recruitment of autophagic responses in the cardiomyocyte energy stress response. In particular, exploration of the links between cell substrate flux, calcium ion (Ca2+) flux, and phagosomal cargo flux is required. Strategies to target specific fuel "bulk" management defects in cardiac energy stress states may be of therapeutic value.
Collapse
Affiliation(s)
- Lorna J Daniels
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Upasna Varma
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
| | - Marco Annandale
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Eleia Chan
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
| | - Kimberley M Mellor
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand.,2 Department of Physiology, University of Melbourne, Melbourne, Australia.,3 Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Lea M D Delbridge
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
| |
Collapse
|
4
|
Halade GV, Kain V, Tourki B, Jadapalli JK. Lipoxygenase drives lipidomic and metabolic reprogramming in ischemic heart failure. Metabolism 2019; 96:22-32. [PMID: 30999004 DOI: 10.1016/j.metabol.2019.04.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/02/2019] [Accepted: 04/11/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND After myocardial infarction (MI), delayed progression or reversal of cardiac remodeling is a prime target to limit advanced chronic heart failure (HF). However, the temporal kinetics of lipidomic and systemic metabolic signaling is unclear in HF. There is no consensus on metabolic and lipidomic signatures that influence structure, function, and survival in HF. Here we use genetic knock out model to delineate lipidomic, and metabolic changes to describe the role of lipoxygenase in advancing ischemic HF driven by leukocyte activation with signs of non-resolving inflammation. Bioactive lipids and metabolites are implicated in acute and chronic HF, and the goal of this study was to define the role of lipoxygenase in temporal kinetics of lipidomic and metabolic reprogramming in HF. MATERIALS AND METHODS To address this question, we used a permanent coronary ligation mouse model which showed profound metabolic and lipidomic reprogramming in acute HF. Additionally, we defined the lipoxygenase-mediated changes in cardiac pathophysiology in acute and chronic HF. For this, we quantitated systemic metabolic changes and lipidomic profiling in infarcted heart tissue with obvious structural remodeling and cardiac dysfunction progressing from acute to chronic HF in the survival cohort. RESULTS After MI, lipoxygenase-derived specialized pro-resolving mediators were quantitated and showed lipoxygenase-deficient mice (12/15LOX-/-) biosynthesize epoxyeicosatrienoic acid (EETs; cypoxins) to facilitate cardiac healing. Lipoxygenase-deficient mice reduced diabetes risk biomarker 2-aminoadipic acid with profound alterations of plasma metabolic signaling of hexoses, amino acids, biogenic amines, acylcarnitines, glycerophospholipids, and sphingolipids in acute HF, thereby improved survival. CONCLUSION Specific lipoxygenase deletion alters lipidomic and metabolic signatures, with modified leukocyte profiling that delayed HF progression and improved survival. Future studies are warranted to define the molecular network of lipidome and metabolome in acute and chronic HF patients.
Collapse
Affiliation(s)
- Ganesh V Halade
- Division of Cardiovascular Disease, Department of Medicine, The University of Alabama at Birmingham, AL, United States.
| | - Vasundhara Kain
- Division of Cardiovascular Disease, Department of Medicine, The University of Alabama at Birmingham, AL, United States
| | - Bochra Tourki
- Division of Cardiovascular Disease, Department of Medicine, The University of Alabama at Birmingham, AL, United States
| | - Jeevan Kumar Jadapalli
- Division of Cardiovascular Disease, Department of Medicine, The University of Alabama at Birmingham, AL, United States
| |
Collapse
|
5
|
Van Wezel HB. Glucose-Insulin-Potassium Techniques in Cardiac Surgery: Historical Overview and Future Perspectives. Semin Cardiothorac Vasc Anesth 2016; 10:224-7. [PMID: 16959755 DOI: 10.1177/1089253206291146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Since the days of the first cardiac surgical operations in the previous century, myocardial preservation has been an essential component of the successful outcome of these procedures. Although many different techniques to achieve myocardial preservation and modulation have been described in the past 50 years, this review focuses on the use of glucose, insulin, and potassium (GIK) and its effect on ischemic and postischemic myocardium.
Collapse
Affiliation(s)
- Harry B Van Wezel
- Department of Anesthesiology, Academic Medical Center, Amsterdam, AZ Amsterdam, The Netherlands.
| |
Collapse
|
6
|
Bolotin G, Raman J, Williams U, Bacha E, Kocherginsky M, Jeevanandam V. Glutamine Improves Myocardial Function following Ischemia-Reperfusion Injury. Asian Cardiovasc Thorac Ann 2016; 15:463-7. [DOI: 10.1177/021849230701500603] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Myocardial ischemia-reperfusion injury is common during cardiac procedures. Glutamine may protect the myocardium by preserving metabolic substrates. Glutamine (0.52 g·kg−1) or Ringer's lactate solution (control group) was administered intraperitoneally to 63 Sprague-Dawley rats at 4 or 18 hours prior to experimental ischemia and reperfusion. The hearts were excised and perfused on an isolated working heart model, exposed to global ischemia for 15 min and reperfusion for 1 hour. Left atrial pressure, mean aortic pressure, cardiac flow, coronary flow, and aortic output were measured 15 min before ischemia and every 15 min during reperfusion. There was significantly better cardiac output in the glutamine pretreated groups. Pretreatment at 4 hours before the experiment was superior to pretreatment at 18 hours, with better maintenance of cardiac output and coronary flow. The enhanced protective effect of pretreatment at 4 hours highlights the importance of timing, and suggests a potential clinical benefit.
Collapse
Affiliation(s)
- Gil Bolotin
- Division of Cardiothoracic, Surgery Pritzker School of Medicine, University of Chicagom, USA
| | - Jai Raman
- Division of Cardiothoracic, Surgery Pritzker School of Medicine, University of Chicagom, USA
| | - Ursula Williams
- Division of Cardiothoracic, Surgery Pritzker School of Medicine, University of Chicagom, USA
| | - Emile Bacha
- Division of Cardiothoracic, Surgery Pritzker School of Medicine, University of Chicagom, USA
| | - Masha Kocherginsky
- Division of Cardiothoracic, Surgery Pritzker School of Medicine, University of Chicagom, USA
| | - Valluvan Jeevanandam
- Division of Cardiothoracic, Surgery Pritzker School of Medicine, University of Chicagom, USA
| |
Collapse
|
7
|
Low T3 State Is Correlated with Cardiac Mitochondrial Impairments after Ischemia Reperfusion Injury: Evidence from a Proteomic Approach. Int J Mol Sci 2015; 16:26687-705. [PMID: 26561807 PMCID: PMC4661832 DOI: 10.3390/ijms161125973] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/13/2015] [Accepted: 10/26/2015] [Indexed: 11/22/2022] Open
Abstract
Mitochondria are major determinants of cell fate in ischemia/reperfusion injury (IR) and common effectors of cardio-protective strategies in cardiac ischemic disease. Thyroid hormone homeostasis critically affects mitochondrial function and energy production. Since a low T3 state (LT3S) is frequently observed in the post infarction setting, the study was aimed to investigate the relationship between 72 h post IR T3 levels and both the cardiac function and the mitochondrial proteome in a rat model of IR. The low T3 group exhibits the most compromised cardiac performance along with the worst mitochondrial activity. Accordingly, our results show a different remodeling of the mitochondrial proteome in the presence or absence of a LT3S, with alterations in groups of proteins that play a key role in energy metabolism, quality control and regulation of cell death pathways. Overall, our findings highlight a relationship between LT3S in the early post IR and poor cardiac and mitochondrial outcomes, and suggest a potential implication of thyroid hormone in the cardio-protection and tissue remodeling in ischemic disease.
Collapse
|
8
|
Drake KJ, Shotwell MS, Wikswo JP, Sidorov VY. Glutamine and glutamate limit the shortening of action potential duration in anoxia-challenged rabbit hearts. Physiol Rep 2015; 3:3/9/e12535. [PMID: 26333831 PMCID: PMC4600381 DOI: 10.14814/phy2.12535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In clinical conditions, amino acid supplementation is applied to improve contractile function, minimize ischemia/reperfusion injury, and facilitate postoperative recovery. It has been shown that glutamine enhances myocardial ATP/APD (action potential duration) and glutathione/oxidized glutathione ratios, and can increase hexosamine biosynthesis pathway flux, which is believed to play a role in cardioprotection. Here, we studied the effect of glutamine and glutamate on electrical activity in Langendorff-perfused rabbit hearts. The hearts were supplied by Tyrode's media with or without 2.5 mmol/L glutamine and 150 μmol/L glutamate, and exposed to two 6-min anoxias with 20-min recovery in between. Change in APD was detected using a monophasic action potential probe. A nonlinear mixed-effects regression technique was used to evaluate the effect of amino acids on APD over the experiment. Typically, the dynamic of APD change encompasses three phases: short transient increase (more prominent in the first episode), slow decrease, and fast increase (starting with the beginning of recovery). The effect of both anoxic challenge and glutamine/glutamate was cumulative, being more pronounced in the second anoxia. The amino acids' protective effect became largest by the end of anoxia – 20.0% (18.9, 95% CI: [2.6 ms, 35.1 ms]), during the first anoxia and 36.6% (27.1, 95% CI: [7.7 ms, 46.6 ms]), during the second. Following the second anoxia, APD difference between control and supplemented hearts progressively increased, attaining 10.8% (13.6, 95% CI: [4.1 ms, 23.1 ms]) at the experiments' end. Our data reveal APD stabilizing and suggest an antiarrhythmic capacity of amino acid supplementation in anoxic/ischemic conditions.
Collapse
Affiliation(s)
- Kenneth J Drake
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee
| | - Matthew S Shotwell
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee
| | - John P Wikswo
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Veniamin Y Sidorov
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| |
Collapse
|
9
|
Lehnen TE, Lehnen AM, Tavares AMV, Belló-Klein A, Markoski MM, Machado UF, Schaan B. Atorvastatin administered before myocardial infarction in rats improves contractility irrespective of metabolic changes. Clin Exp Pharmacol Physiol 2014; 41:986-94. [DOI: 10.1111/1440-1681.12313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 08/27/2014] [Accepted: 09/03/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Tatiana Ederich Lehnen
- Postgraduate Program in Endocrinology; Federal University of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
- Endocrine Division; Hospital de Clínicas de Porto Alegre; Porto Alegre Rio Grande do Sul Brazil
- Institute of Cardiology/University Foundation of Cardiology of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| | - Alexandre Machado Lehnen
- Postgraduate Program in Endocrinology; Federal University of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
- Endocrine Division; Hospital de Clínicas de Porto Alegre; Porto Alegre Rio Grande do Sul Brazil
- Institute of Cardiology/University Foundation of Cardiology of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| | - Angela Maria Vicente Tavares
- Laboratory of Cardiovascular Physiology; Institute of Basic Health Sciences; Federal University of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| | - Adriane Belló-Klein
- Laboratory of Cardiovascular Physiology; Institute of Basic Health Sciences; Federal University of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| | - Melissa Medeiros Markoski
- Institute of Cardiology/University Foundation of Cardiology of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| | - Ubiratan Fabres Machado
- Department of Physiology and Biophysics; Institute of Biomedical Sciences; University of São Paulo; São Paulo Brazil
| | - Beatriz Schaan
- Postgraduate Program in Endocrinology; Federal University of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
- Endocrine Division; Hospital de Clínicas de Porto Alegre; Porto Alegre Rio Grande do Sul Brazil
- Institute of Cardiology/University Foundation of Cardiology of Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| |
Collapse
|
10
|
Bodi V, Marrachelli VG, Husser O, Chorro FJ, Viña JR, Monleon D. Metabolomics in the diagnosis of acute myocardial ischemia. J Cardiovasc Transl Res 2013; 6:808-15. [PMID: 23990264 DOI: 10.1007/s12265-013-9505-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/06/2013] [Indexed: 11/30/2022]
Abstract
Despite recent advances in the diagnosis of myocardial ischemia, its biochemical identification in patients with acute chest pain is still a challenge, and alternative approaches for further improvement are needed. Metabolic alterations are the first consequences of acute myocardial ischemia. Metabolomics coupled with potent multivariate analyses allows for a simultaneous and relative quantification of thousands of different metabolites within a given sample. Thus, this discipline might exert a great impact on medical practice in cardiovascular medicine by providing a wealth of relevant biochemical data. Metabolomics is a promising tool to improve current, single biomarker-based approaches by identifying metabolic biosignatures that embody global biochemical changes in disease. This is especially relevant for conditions requiring early treatment like myocardial ischemia. This review discusses the potential application of metabolomics in the diagnosis of myocardial ischemia.
Collapse
Affiliation(s)
- Vicente Bodi
- Cardiology Department, Hospital Clinico Universitario, INCLIVA, University of Valencia, Blasco Ibanez 17, 46010, Valencia, Spain,
| | | | | | | | | | | |
Collapse
|
11
|
Unique transcriptional profile of sustained ligand-activated preconditioning in pre- and post-ischemic myocardium. PLoS One 2013; 8:e72278. [PMID: 23991079 PMCID: PMC3749099 DOI: 10.1371/journal.pone.0072278] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 07/15/2013] [Indexed: 01/07/2023] Open
Abstract
Background Opioidergic SLP (sustained ligand-activated preconditioning) induced by 3–5 days of opioid receptor (OR) agonism induces persistent protection against ischemia-reperfusion (I-R) injury in young and aged hearts, and is mechanistically distinct from conventional preconditioning responses. We thus applied unbiased gene-array interrogation to identify molecular effects of SLP in pre- and post-ischemic myocardium. Methodology/Principal Findings Male C57Bl/6 mice were implanted with 75 mg morphine or placebo pellets for 5 days. Resultant SLP did not modify cardiac function, and markedly reduced dysfunction and injury in perfused hearts subjected to 25 min ischemia/45 min reperfusion. Microarray analysis identified 14 up- and 86 down-regulated genes in normoxic hearts from SLP mice (≥1.3-fold change, FDR≤5%). Induced genes encoded sarcomeric/contractile proteins (Myh7, Mybpc3,Myom2,Des), natriuretic peptides (Nppa,Nppb) and stress-signaling elements (Csda,Ptgds). Highly repressed genes primarily encoded chemokines (Ccl2,Ccl4,Ccl7,Ccl9,Ccl13,Ccl3l3,Cxcl3), cytokines (Il1b,Il6,Tnf) and other proteins involved in inflammation/immunity (C3,Cd74,Cd83, Cd86,Hla-dbq1,Hla-drb1,Saa1,Selp,Serpina3), together with endoplasmic stress proteins (known: Dnajb1,Herpud1,Socs3; putative: Il6, Gadd45g,Rcan1) and transcriptional controllers (Egr2,Egr3, Fos,Hmox1,Nfkbid). Biological themes modified thus related to inflammation/immunity, together with cellular/cardiovascular movement and development. SLP also modified the transcriptional response to I-R (46 genes uniquely altered post-ischemia), which may influence later infarction/remodeling. This included up-regulated determinants of cellular resistance to oxidant (Mgst3,Gstm1,Gstm2) and other forms of stress (Xirp1,Ankrd1,Clu), and repression of stress-response genes (Hspa1a,Hspd1,Hsp90aa,Hsph1,Serpinh1) and Txnip. Conclusions Protection via SLP is associated with transcriptional repression of inflammation/immunity, up-regulation of sarcomeric elements and natriuretic peptides, and modulation of cell stress, growth and development, while conventional protective molecules are unaltered.
Collapse
|
12
|
Grossman AN, Opie LH, Beshansky JR, Ingwall JS, Rackley CE, Selker HP. Glucose-insulin-potassium revived: current status in acute coronary syndromes and the energy-depleted heart. Circulation 2013; 127:1040-8. [PMID: 23459576 DOI: 10.1161/circulationaha.112.130625] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
13
|
Shim JK, Yang SY, Yoo YC, Yoo KJ, Kwak YL. Myocardial protection by glucose–insulin–potassium in acute coronary syndrome patients undergoing urgent multivessel off-pump coronary artery bypass surgery. Br J Anaesth 2013; 110:47-53. [DOI: 10.1093/bja/aes324] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
14
|
Drake KJ, Sidorov VY, McGuinness OP, Wasserman DH, Wikswo JP. Amino acids as metabolic substrates during cardiac ischemia. Exp Biol Med (Maywood) 2012; 237:1369-78. [PMID: 23354395 PMCID: PMC3816490 DOI: 10.1258/ebm.2012.012025] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The heart is well known as a metabolic omnivore in that it is capable of consuming fatty acids, glucose, ketone bodies, pyruvate, lactate, amino acids and even its own constituent proteins, in order of decreasing preference. The energy from these substrates supports not only mechanical contraction, but also the various transmembrane pumps and transporters required for ionic homeostasis, electrical activity, metabolism and catabolism. Cardiac ischemia - for example, due to compromise of the coronary vasculature or end-stage heart failure - will alter both electrical and metabolic activity. While the effects of myocardial ischemia on electrical propagation and stability have been studied in depth, the effects of ischemia on metabolic substrate preference has not been fully appreciated: oxygen deprivation during ischemia will significantly alter the relative ability of the heart to utilize each of these substrates. Although changes in cardiac metabolism are understood to be an underlying component in almost all cardiac myopathies, the potential contribution of amino acids in maintaining cardiac electrical conductance and stability during ischemia is underappreciated. Despite clear evidence that amino acids exert cardioprotective effects in ischemia and other cardiac disorders, their role in the metabolism of the ischemic heart has yet to be fully elucidated. This review synthesizes the current literature of the metabolic contribution of amino acids during ischemia by analyzing relevant historical and recent research.
Collapse
Affiliation(s)
- Kenneth J. Drake
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235
| | - Veniamin Y. Sidorov
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235
| | - Owen P. McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235
| | - David H. Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232
| | - John P. Wikswo
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235
| |
Collapse
|
15
|
Suranadi IW, Demaison L, Chaté V, Peltier S, Richardson M, Leverve X. An increase in the redox state during reperfusion contributes to the cardioprotective effect of GIK solution. J Appl Physiol (1985) 2012; 113:775-84. [PMID: 22797310 DOI: 10.1152/japplphysiol.01153.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
This study aimed at determining whether glucose-insulin-potassium (GIK) solutions modify the NADH/NAD(+) ratio during postischemic reperfusion and whether their cardioprotective effect can be attributed to this change in part through reduction of the mitochondrial reactive oxygen species (ROS) production. The hearts of 72 rats were perfused with a buffer containing glucose (5.5 mM) and hexanoate (0.5 mM). They were maintained in normoxia for 30 min and then subjected to low-flow ischemia (0.5% of the preischemic coronary flow for 20 min) followed by reperfusion (45 min). From the beginning of ischemia, the perfusate was subjected to various changes: enrichment with GIK solution, enrichment with lactate (2 mM), enrichment with pyruvate (2 mM), enrichment with pyruvate (2 mM) plus ethanol (2 mM), or no change for the control group. Left ventricular developed pressure, heart rate, coronary flow, and oxygen consumption were monitored throughout. The lactate/pyruvate ratio of the coronary effluent, known to reflect the cytosolic NADH/NAD(+) ratio and the fructose-6-phosphate/dihydroxyacetone-phosphate (F6P/DHAP) ratio of the reperfused myocardium, were evaluated. Mitochondrial ROS production was also estimated. The GIK solution improved the recovery of mechanical function during reperfusion. This was associated with an enhanced cytosolic NADH/NAD(+) ratio and reduced mitochondrial ROS production. The cardioprotection was also observed when the hearts were perfused with fluids known to increase the cytosolic NADH/NAD(+) ratio (lactate, pyruvate plus ethanol) compared with the other fluids (control and pyruvate groups). The hearts with a high mechanical recovery also displayed a low F6P/DHAP ratio, suggesting that an accelerated glycolysis rate may be responsible for increased cytosolic NADH production. In conclusion, the cardioprotection induced by GIK solutions could occur through an increase in the cytosolic NADH/NAD(+) ratio, leading to a decrease in mitochondrial ROS production.
Collapse
Affiliation(s)
- I W Suranadi
- Faculty of Medicine, Udayana University, Denpasar, Bali, Indonesia
| | | | | | | | | | | |
Collapse
|
16
|
Croteau E, Gascon S, Bentourkia M, Langlois R, Rousseau JA, Lecomte R, Bénard F. [11C]Acetate rest-stress protocol to assess myocardial perfusion and oxygen consumption reserve in a model of congestive heart failure in rats. Nucl Med Biol 2011; 39:287-94. [PMID: 22079038 DOI: 10.1016/j.nucmedbio.2011.07.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 07/23/2011] [Accepted: 07/26/2011] [Indexed: 10/15/2022]
Abstract
UNLABELLED This study describes an [(11)C]acetate rest-stress method to obtain an indirect estimate of myocardial blood flow (MBF) and myocardial oxygen consumption (MVO(2)) in rats. Doxorubicin cardiotoxicity was used to test the usefulness of this approach for the assessment of congestive heart failure. METHODS [(11)C]Acetate rest-stress studies have been used in clinical research to assess the capacity of the coronary arteries to respond to stress. In this article, we used this approach to assess the cardiotoxicity of doxorubicin in a rat model. The method was first validated in a group of healthy rats and then used to follow the effect of doxorubicin chemotherapy on cardiac function. The effect of doxorubicin on myocardial perfusion and oxygen consumption reserve was measured at rest and under dobutamine stimulation. RESULTS Validation of the protocol showed a good correlation between the MBF and MVO(2) (r(2)=.68). The doxorubicin-treated group showed a significant (P=.04) decrease in cardiovascular perfusion reserve at 1.3±0.2 compared with the control animals at 1.6±0.2. Similar results were obtained for the MVO(2) reserve (treated 1.8±0.4 vs. controls 2.3±0.3; P=.02). CONCLUSIONS We describe an [(11)C]acetate PET rest-stress protocol for the assessment of congestive heart failure in rats and its application to the follow-up of cardiotoxicity under doxorubicin chemotherapy. This is a rapid and reliable approach to the measurement of cardiac perfusion and oxygen consumption reserve that could be applied to the development of new strategies to reduce the cardiotoxicity of anthracycline.
Collapse
Affiliation(s)
- Etienne Croteau
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke and Sherbrooke Molecular Imaging Center, Étienne-LeBel Clinical Research Center, CHUS, Sherbrooke, QC, Canada.
| | | | | | | | | | | | | |
Collapse
|
17
|
Dzeja PP, Hoyer K, Tian R, Zhang S, Nemutlu E, Spindler M, Ingwall JS. Rearrangement of energetic and substrate utilization networks compensate for chronic myocardial creatine kinase deficiency. J Physiol 2011; 589:5193-211. [PMID: 21878522 DOI: 10.1113/jphysiol.2011.212829] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Plasticity of the cellular bioenergetic system is fundamental to every organ function, stress adaptation and disease tolerance. Here, remodelling of phosphotransfer and substrate utilization networks in response to chronic creatine kinase (CK) deficiency, a hallmark of cardiovascular disease, has been revealed in transgenic mouse models lacking either cytosolic M-CK (M-CK(-/-)) or both M-CK and sarcomeric mitochondrial CK (M-CK/ScCKmit(-/-)) isoforms. The dynamic metabolomic signatures of these adaptations have also been defined. Tracking perturbations in metabolic dynamics with (18)O and (13)C isotopes and (31)P NMR and mass spectrometry demonstrate that hearts lacking M-CK have lower phosphocreatine (PCr) turnover but increased glucose-6-phosphate (G-6-P) turnover, glucose utilization and inorganic phosphate compartmentation with normal ATP γ-phosphoryl dynamics. Hearts lacking both M-CK and sarcomeric mitochondrial CK have diminished PCr turnover, total phosphotransfer capacity and intracellular energetic communication but increased dynamics of β-phosphoryls of ADP/ATP, G-6-P and γ-/β-phosphoryls of GTP, indicating redistribution of flux through adenylate kinase (AK), glycolytic and guanine nucleotide phosphotransfer circuits. Higher glycolytic and mitochondrial capacities and increased glucose tolerance contributed to metabolic resilience of M-CK/ScCKmit(-/-) mice. Multivariate analysis revealed unique metabolomic signatures for M-CK(-/-) and M-CK/ScCKmit(-/-) hearts suggesting that rearrangements in phosphotransfer and substrate utilization networks provide compensation for genetic CK deficiency. This new information highlights the significance of integrated CK-, AK-, guanine nucleotide- and glycolytic enzyme-catalysed phosphotransfer networks in supporting the adaptivity and robustness of the cellular energetic system.
Collapse
Affiliation(s)
- Petras P Dzeja
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA.
| | | | | | | | | | | | | |
Collapse
|
18
|
Klein LJ, Visser FC. The effect of insulin on the heart : Part 1: Effects on metabolism and function. Neth Heart J 2011; 18:197-201. [PMID: 20428418 DOI: 10.1007/bf03091761] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Positive inotropic effects of insulin were described early after the isolation of insulin from the pancreas but data on the effect of insulin on the heart are conflicting. Systemic insulin administration results in a reduction in circulating free fatty acids and an improvement in myocardial glucose uptake, which causes an efficiency improvement in the myocardial cell. There is strong evidence that insulin administration results in functional improvement in dysfunctional myocardium. (Neth Heart J 2010;18:197-201.).
Collapse
Affiliation(s)
- L J Klein
- Department of Cardiology, VU Medical Centre, Amsterdam, the Netherlands
| | | |
Collapse
|
19
|
Hyperglycemia attenuates myocardial preconditioning of remifentanil. J Surg Res 2011; 174:231-7. [PMID: 21392805 DOI: 10.1016/j.jss.2011.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 12/13/2010] [Accepted: 01/11/2011] [Indexed: 01/08/2023]
Abstract
BACKGROUND Hyperglycemia attenuates cardioprotection by remifentanil-preconditioning in ischemia-reperfusion in vivo in diabetic rats. However, the effects of hyperglycemia in cultured ventricular myocytes remains unknown. Therefore, we examined the in vitro effects of hyperglycemia on hypoxia-reoxygenation (H/R) and cardioprotection from remifentanil-preconditioning in isolated neonatal rat ventricular myocytes (NRVMs), including effects on apoptotic signaling pathways and Ca(2+) homeostasis. MATERIALS AND METHODS NRVMs were cultured in medium with 5.5 mM (normoglycemia) or 25.5 mM glucose for one day. Then, NRVMs in H/R groups were exposed to 1 h of hypoxia and 5 h of reoxygenation with or without remifentanil-preconditioning at 1 μM. Cell viability, apoptosis, and Ca(2+) homeostasis were assessed by MTT assay, caspase-3 assay, confocal microscopy and immunoblots. RESULTS In normoglycemia, remifentanil-preconditioning improved the viability of cardiomyocytes (P < 0.01) and prevented the increase of caspase-3 activity and Ca(2+) overload after H/R injury (P < 0.05). In addition, decrease in Akt, ERK1/2, and Bcl-2, and the increase in Bax by H/R was attenuated by remifentanil-preconditioning (P < 0.05). However, in hyperglycemia, the viability was partially impaired after H/R but not improved by remifentanil-preconditioning. Apoptotic activity, Ca(2+) concentration, and apoptotic kinases except Akt were not affected by either H/R or remifentanil-preconditioning under hyperglycemia. Akt phosphorylation was decreased by H/R but not restored by remifentanil preconditioning. CONCLUSIONS Remifentanil preconditioning under normoglycemia renders NRVMs resistant to H/R injury by reducing apoptosis and intracellular Ca(2+) concentrations. The mechanism appears to be modulation of apoptotic signaling. However, hyperglycemia mitigates H/R injury in NRVMs, and may reduce the protective effect of remifentanil-preconditioning that may be associated with the Akt pathways.
Collapse
|
20
|
Chambers KT, Leone TC, Sambandam N, Kovacs A, Wagg CS, Lopaschuk GD, Finck BN, Kelly DP. Chronic inhibition of pyruvate dehydrogenase in heart triggers an adaptive metabolic response. J Biol Chem 2011; 286:11155-62. [PMID: 21321124 DOI: 10.1074/jbc.m110.217349] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Diabetic cardiac dysfunction is associated with decreased rates of myocardial glucose oxidation (GO) and increased fatty acid oxidation (FAO), a fuel shift that has been shown to sensitize the heart to ischemic insult and ventricular dysfunction. We sought to evaluate the metabolic and functional consequences of chronic suppression of GO in heart as modeled by transgenic mice with cardiac-specific overexpression of pyruvate dehydrogenase kinase 4 (myosin heavy chain (MHC)-PDK4 mice), an inhibitor of pyruvate dehydrogenase. Hearts of MHC-PDK4 mice were shown to exhibit an insulin-resistant substrate utilization profile, characterized by low GO rates and high FAO flux. Surprisingly, MHC-PDK4 mice were not sensitized to cardiac ischemia-reperfusion injury despite a fuel utilization pattern that phenocopied the diabetic heart. In addition, MHC-PDK4 mice were protected against high fat diet-induced myocyte lipid accumulation, likely related to increased capacity for FAO. The high rates of mitochondrial FAO in the MHC-PDK4 heart were related to heightened activity of the AMP-activated protein kinase, reduced levels of malonyl-CoA, and increased capacity for mitochondrial uncoupled respiration. The expression of the known AMP-activated protein kinase target, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a master regulator of mitochondrial function and biogenesis, was also activated in the MHC-PDK4 heart. These results demonstrate that chronic activation of PDK4 triggers transcriptional and post-transcriptional mechanisms that re-program the heart for chronic high rates of FAO without the expected deleterious functional or metabolic consequences.
Collapse
Affiliation(s)
- Kari T Chambers
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Effect of glucose-insulin-potassium in severe acute heart failure after brain death*. Crit Care Med 2008; 36:2740-5. [DOI: 10.1097/ccm.0b013e318186f64b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
22
|
Zuurbier CJ, Hoek FJ, van Dijk J, Abeling NG, Meijers JCM, Levels JHM, de Jonge E, de Mol BA, Van Wezel HB. Perioperative hyperinsulinaemic normoglycaemic clamp causes hypolipidaemia after coronary artery surgery. Br J Anaesth 2008; 100:442-50. [PMID: 18305079 DOI: 10.1093/bja/aen018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Glucose-insulin-potassium (GIK) administration is advocated on the premise of preventing hyperglycaemia and hyperlipidaemia during reperfusion after cardiac interventions. Current research has focused on hyperglycaemia, largely ignoring lipids, or other substrates. The present study examines lipids and other substrates during and after on-pump coronary artery bypass grafting and how they are affected by a hyperinsulinaemic normoglycaemic clamp. METHODS Forty-four patients were randomized to a control group (n=21) or to a GIK group (n=23) receiving a hyperinsulinaemic normoglycaemic clamp during 26 h. Plasma levels of free fatty acid (FFA), total and lipoprotein (VLDL, HDL, and LDL)-triglycerides (TG), ketone bodies, and lactate were determined. RESULTS In the control group, mean FFA peaked at 0.76 (sem 0.05) mmol litre(-1) at early reperfusion and decreased to 0.3-0.5 mmol litre(-1) during the remaining part of the study. GIK decreased FFA levels to 0.38 (0.05) mmol litre(-1) at early reperfusion, and to low concentrations of 0.10 (0.01) mmol litre(-1) during the hyperinsulinaemic clamp. GIK reduced the area under the curve (AUC) for FFA by 75% and for TG by 53%. The reduction in total TG was reflected by a reduction in the VLDL (-54% AUC) and HDL (-42% AUC) fraction, but not in the LDL fraction. GIK prevented the increase in ketone bodies after reperfusion (-44 to -47% AUC), but was without effect on lactate levels. CONCLUSIONS Mild hyperlipidaemia was only observed during early reperfusion (before heparin reversal) and the hyperinsulinaemic normoglycaemic clamp actually resulted in hypolipidaemia during the largest part of reperfusion after cardiac surgery.
Collapse
Affiliation(s)
- C J Zuurbier
- Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Saager L, Collins GL, Burnside B, Tymkew H, Zhang L, Jacobsohn E, Avidan M. A randomized study in diabetic patients undergoing cardiac surgery comparing computer-guided glucose management with a standard sliding scale protocol. J Cardiothorac Vasc Anesth 2007; 22:377-82. [PMID: 18503924 DOI: 10.1053/j.jvca.2007.09.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The aim of this study was to compare a standard insulin protocol with a computer-guided glucose management system to determine which method achieves tighter glucose control. DESIGN A prospective, randomized trial. SETTING A cardiothoracic intensive care unit (ICU) in a large academic medical center. PARTICIPANTS Forty patients with diabetes mellitus who were scheduled for cardiac surgery. INTERVENTIONS After induction of anesthesia and for the first 9 hours in the ICU, each subject received a standardized infusion of a 10% glucose solution at a rate of 1.0 mL/kg/h (ideal body weight). The subjects were then randomized to have their glucose controlled by either a paper-based insulin protocol or by a computer-guided glucose management system (CG). The desired range for blood glucose was set between 90 and 150 mg/dL. MEASUREMENTS AND MAIN RESULTS There were no differences between groups in baseline characteristics. Patients in the CG group spent more time in the desired range during both the intraoperative phase (49% v 27%, p = 0.001) and the ICU phase (84% v 60%, p < 0.0001). There were no statistical differences between groups in the number of hypoglycemia episodes. CONCLUSIONS The computer-guided glucose management system achieved tighter blood glucose control than a standard paper-based protocol in diabetic patients undergoing cardiac surgery. However, the low proportion of blood glucose recordings within the desired range in both groups during the intraoperative period reflects the challenges associated with achieving normoglycemia during cardiac surgery.
Collapse
Affiliation(s)
- Leif Saager
- Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Myocardial Protection During Elective Coronary Artery Bypass Grafting Using High-Dose Insulin Therapy. Ann Thorac Surg 2007; 84:1920-7; discussion 1920-7. [DOI: 10.1016/j.athoracsur.2007.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 06/29/2007] [Accepted: 07/02/2007] [Indexed: 01/04/2023]
|
25
|
Affiliation(s)
- Christopher J Pastore
- Division of Cardiology, Department of Medicine, Tufts-New England Medical Center, Boston, MA 02111, USA
| | | | | |
Collapse
|
26
|
Støttrup NB, Kristiansen SB, Løfgren B, Hansen BF, Kimose HH, Bøtker HE, Nielsen TT. L-glutamate and glutamine improve haemodynamic function and restore myocardial glycogen content during postischaemic reperfusion: A radioactive tracer study in the rat isolated heart. Clin Exp Pharmacol Physiol 2007; 33:1099-103. [PMID: 17042921 DOI: 10.1111/j.1440-1681.2006.04497.x] [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: 11/26/2022]
Abstract
1. L-Glutamate and glutamine have been suggested to have cardioprotective effects. However, the issue is controversial and the metabolic mechanisms underlying a beneficial effect are not well understood. 2. In the present study we investigated the effects of L-glutamate and glutamine on haemodynamic recovery, the rate of de novo glycogen synthesis and myocardial glucose uptake during postischaemic reperfusion. 3. Hearts from male Wistar rats (250-300 g) were divided into three groups as follows: (i) control (n = 12); (ii) L-glutamate (n = 12); and (iii) glutamine (n = 12). Hearts were mounted in a Langendorff preparation and perfused with oxygenated Krebs'-Henseleit solution at 80 mmHg and 37C. Global ischaemia for 20 min was followed by 15 min reperfusion, during which L-glutamate (50 mmol/L) or glutamine (20 mmol/L) were administered. Left ventricular developed pressure (LVDP), de novo synthesis of glycogen using [14C]-glucose and myocardial glucose uptake using D-[2-3H]-glucose were measured. 4. L-Glutamate and glutamine increased postischaemic LVDP (P < 0.01 vs control hearts for both). L-Glutamate and glutamine increased de novo glycogen synthesis by 78% (P < 0.001) and 55% (P < 0.01), respectively. At the end of reperfusion, total myocardial glycogen content was increased by both L-glutamate and glutamine (5.7 +/- 0.3 and 6.2 +/- 0.7 micromol/g wet weight, respectively; P < 0.05 and 0.01, respectively) compared with that in control hearts (3.6 +/- 0.4 micromol/g wet weight). Neither L-glutamate nor glutamine affected myocardial glucose uptake during reperfusion. 5. Improved postischaemic haemodynamic recovery after L-glutamate and glutamine supplementation during reperfusion is associated with increased de novo glycogen synthesis, suggesting a favourable modulation of intracellular myocardial carbohydrate metabolism.
Collapse
Affiliation(s)
- Nicolaj B Støttrup
- Department of Cardiology, Skejby Sygehus, Aarhus University Hospital, Aarhus, Denmark.
| | | | | | | | | | | | | |
Collapse
|
27
|
van Wezel HB, Zuurbier CJ, de Jonge E, van Dam EWCM, van Dijk J, Endert E, de Mol BA, Fliers E. Differential effects of a perioperative hyperinsulinemic normoglycemic clamp on the neurohumoral stress response during coronary artery surgery. J Clin Endocrinol Metab 2006; 91:4144-53. [PMID: 16895948 DOI: 10.1210/jc.2006-1199] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND Hyperglycemia in patients undergoing coronary artery bypass grafting (CABG) is associated with adverse outcome. Although insulin infusion strategies are increasingly used to improve outcome, a pathophysiological rationale is currently lacking. The present study was designed to quantify the effects of a perioperative hyperinsulinemic normoglycemic clamp on the neurohumoral stress response during CABG. METHODS Forty-four nondiabetic patients, scheduled for elective CABG, were randomized to either a control group (n = 22) receiving standard care or to a clamp group (n = 22) receiving additionally a perioperative hyperinsulinemic (regular insulin at a fixed rate of 0.1 IU.kg(-1).h(-1)) normoglycemic (plasma glucose between 3.0 and 6.0 mmol.liter(-1)) clamp during 26 h. We measured the endocrine response of the hypothalamus-pituitary-adrenal (HPA) axis, the sympathoadrenal axis, and glucagon, as well as plasma glucose and insulin at regular intervals from the induction of anesthesia at baseline through the end of the second postoperative day (POD). RESULTS There were no differences in clinical outcome between the groups. In the control group, hyperglycemia developed at the end of surgery and remained present until the final measurement point on POD2, whereas plasma insulin levels remained unchanged until the morning of POD1. In the intervention group, normoglycemia was well maintained during the clamp, whereas insulin levels ranged between 600 and 800 pmol.liter(-1). In both groups, plasma ACTH and cortisol increased from 6 h after discontinuation of cardiopulmonary bypass onward. However, during the clamp period, a marked reduction in the HPA axis response was found in the intervention group, as reflected by a 47% smaller increase in area under the curve in plasma ACTH (P = 0.035) and a 27% smaller increase in plasma cortisol (P = 0.002) compared with the control group. Compared with baseline, epinephrine and norepinephrine increased by the end of the clamp interval until POD2 in both groups. Surprisingly, the area under the curve of epinephrine levels was 47% higher (P = 0.026) after the clamp interval in the intervention group as compared with the control group. CONCLUSION A hyperinsulinemic normoglycemic clamp during CABG delays and attenuates the HPA axis response during the first 18 h of the myocardial reperfusion period, whereas after the clamp, plasma epinephrine is higher. The impact of delaying cortisol responses on clinical outcome of CABG remains to be elucidated.
Collapse
Affiliation(s)
- H B van Wezel
- Department of Anesthesia, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Thim T, Bentzon JF, Kristiansen SB, Simonsen U, Andersen HL, Wassermann K, Falk E. Size of myocardial infarction induced by ischaemia/reperfusion is unaltered in rats with metabolic syndrome. Clin Sci (Lond) 2006; 110:665-71. [PMID: 16448385 DOI: 10.1042/cs20050326] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Obesity is associated with metabolic syndrome and increased incidence of and mortality from myocardial infarction. The aim of the present study was to develop an animal model with metabolic syndrome and examine how that influences size of myocardial infarcts induced by occlusion and reperfusion of the left anterior descending coronary artery. Sprague–Dawley rats (n=105) were fed either LF (low-fat) or MHF (moderately high-fat) diets for 13 weeks before coronary occlusion for 45 min, followed by reperfusion for 60 min. Compared with LF-fed and lean MHF-fed rats, obese MHF-fed rats developed metabolic disturbances similar to those seen in the metabolic syndrome, including being overweight by 24% (compared with lean MHF-fed rats), having 74% more visceral fat (compared with LF-fed rats), 15% higher blood pressure (compared with LF-fed rats), 116% higher plasma insulin (compared with lean MHF-fed rats), 10% higher fasting plasma glucose (compared with LF-fed rats), 35% higher non-fasting plasma glucose (compared with lean MHF-fed rats), 36% higher plasma leptin (compared with lean MHF-fed rats) and a tendency to lower plasma adiponectin and higher plasma non-esterified fatty acids. Infarct size was similar in the three groups of rats (36±14, 42±18 and 41±14% in obese MHF-fed, lean MHF-fed and LF-fed rats respectively). In conclusion, rats fed a MHF diet developed metabolic syndrome, but this did not influence myocardial infarct size.
Collapse
Affiliation(s)
- Troels Thim
- Department of Cardiology and Institute of Clinical Medicine, Aarhus University Hospital (Skejby), Aarhus, Denmark.
| | | | | | | | | | | | | |
Collapse
|
29
|
Hafstad AD, Solevåg GH, Severson DL, Larsen TS, Aasum E. Perfused hearts from Type 2 diabetic (db/db) mice show metabolic responsiveness to insulin. Am J Physiol Heart Circ Physiol 2006; 290:H1763-9. [PMID: 16327015 DOI: 10.1152/ajpheart.01063.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diabetic ( db/db) mice provide an animal model of Type 2 diabetes characterized by marked in vivo insulin resistance. The effect of insulin on myocardial metabolism has not been fully elucidated in this diabetic model. In the present study we tested the hypothesis that the metabolic response to insulin in db/db hearts will be diminished due to cardiac insulin resistance. Insulin-induced changes in glucose oxidation (GLUox) and fatty acid (FA) oxidation (FAox) were measured in isolated hearts from control and diabetic mice, perfused with both low as well as high concentration of glucose and FA: 10 mM glucose/0.5 mM palmitate and 28 mM glucose/1.1 mM palmitate. Both in the absence and presence of insulin, diabetic hearts showed decreased rates of GLUox and elevated rates of FAox. However, the insulin-induced increment in GLUox, as well as the insulin-induced decrement in FAox, was similar or even more pronounced in diabetic that in control hearts. During elevated FA and glucose supply, however, the effect of insulin was blunted in db/db hearts with respect to both FAox and GLUox. Finally, insulin-stimulated deoxyglucose uptake was markedly reduced in isolated cardiomyocytes from db/db mice, whereas glucose uptake in isolated perfused db/db hearts was clearly responsive to insulin. These results show that, despite reduced insulin-stimulated glucose uptake in isolated cardiomyocytes, isolated perfused db/db hearts are responsive to metabolic actions of insulin. These results should advocate the use of insulin therapy (glucose-insulin-potassium) in diabetic patients undergoing cardiac surgery or during reperfusion after an ischemic insult.
Collapse
Affiliation(s)
- Anne Dragøy Hafstad
- Department of Medical Physiology, Institute of Medical Biology, Faculty of Medicine, University of Tromsø, N-9037 Tromsø, Norway
| | | | | | | | | |
Collapse
|
30
|
Clanachan AS. Contribution of Protons to Post-Ischemic Na+ and Ca2+ Overload and Left Ventricular Mechanical Dysfunction. J Cardiovasc Electrophysiol 2006; 17 Suppl 1:S141-S148. [PMID: 16686669 DOI: 10.1111/j.1540-8167.2006.00395.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The intracellular accumulation of Na(+) and Ca(2+) plays a key role in ischemia-induced myocardial injury that may be manifest as left ventricular (LV) mechanical dysfunction, dysrhythmias, or infarction. This review considers the potential contributions of protons (H(+)) produced during ischemia as well as reperfusion to intracellular Na(+) and Ca(2+) homeostasis. ATP hydrolysis produces H(+) and the resulting intracellular acidosis directly impairs LV contractility. However, it is the accumulation of intracellular H(+) and the activation of Na(+)-dependent pH regulatory mechanisms, including the Na(+)-H(+) exchanger (NHE-1) and the Na(+)-HCO(3) (-) cotransporter, which contribute to Na(+) accumulation. Intracellular Na(+) accumulation, coupled with the NHE-1, then causes Ca(2+) overload and further LV mechanical dysfunction. As glycolysis uncoupled from glucose oxidation is an important determinant of the rate of H(+) production, factors that affect glucose metabolism, including degree of ischemia, myocardial workload, and competition from other energy substrates, are expected to influence Na(+) and Ca(2+) accumulation, and hence the recovery of post-ischemic LV mechanical function. Whereas an increase in the uncoupling of glycolysis from glucose oxidation accelerates H(+) production and worsens the recovery of LV mechanical function, inhibition of H(+) production improves recovery of post-ischemic LV mechanical function. Thus, alteration of glucose metabolism, either by inhibition of an excessive rate of glycolysis or by stimulation of glucose oxidation, is an attractive drug target to reduce H(+) production and limit Na(+) and Ca(2+) accumulation and thereby prevent post-ischemic LV dysfunction.
Collapse
Affiliation(s)
- Alexander S Clanachan
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
| |
Collapse
|
31
|
d'Agostino C, Labinskyy V, Lionetti V, Chandler MP, Lei B, Matsuo K, Bellomo M, Xu X, Hintze TH, Stanley WC, Recchia FA. Altered cardiac metabolic phenotype after prolonged inhibition of NO synthesis in chronically instrumented dogs. Am J Physiol Heart Circ Physiol 2006; 290:H1721-6. [PMID: 16428341 DOI: 10.1152/ajpheart.00745.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acute inhibition of nitric oxide (NO) synthase causes a reversible alteration in myocardial substrate metabolism. We tested the hypothesis that prolonged NO synthase inhibition alters cardiac metabolic phenotype. Seven chronically instrumented dogs were treated with Nω-nitro-l-arginine methyl ester (l-NAME, 35 mg·kg−1·day−1po) for 10 days to inhibit NO synthesis, and seven were used as controls. Cardiac free fatty acid, glucose, and lactate oxidation were measured by infusion of [3H]oleate, [14C]glucose, and [13C]lactate, respectively. After 10 days of l-NAME administration, despite no differences in left ventricular afterload, cardiac O2consumption was significantly increased by 30%, consistent with a marked enhancement in baseline oxidation of glucose (6.9 ± 2.0 vs. 1.7 ± 0.5 μmol·min−1·100 g−1, P < 0.05 vs. control) and lactate (21.6 ± 5.6 vs. 11.8 ± 2.6 μmol·min−1·100 g−1, P < 0.05 vs. control). When left ventricular afterload was increased by ANG II infusion to stimulate myocardial metabolism, glucose oxidation was augmented further in the l-NAME than in the control group, whereas free fatty acid oxidation decreased. Exogenous NO (diethylamine nonoate, 0.01 μmol·kg−1·min−1iv) could not reverse this metabolic alteration. Consistent with the accelerated rate of carbohydrate oxidation, total myocardial pyruvate dehydrogenase activity and protein expression were higher (38 and 34%, respectively) in the l-NAME than in the control group. Also, protein expression of the constitutively active glucose transporter GLUT-1 was significantly elevated (46%) vs. control. We conclude that prolonged NO deficiency causes a profound alteration in cardiac metabolic phenotype, characterized by selective potentiation of carbohydrate oxidation, that cannot be reversed by a short-term infusion of exogenous NO. This phenomenon may constitute an adaptive mechanism to counterbalance cardiac mechanical inefficiency.
Collapse
Affiliation(s)
- Chiara d'Agostino
- Dept. of Physiology, New York Medical College, Valhalla, NY 10595, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Malliopoulou V, Xinaris C, Mourouzis I, Cokkinos AD, Katsilambros N, Pantos C, Kardami E, Cokkinos DV. High glucose protects embryonic cardiac cells against simulated ischemia. Mol Cell Biochem 2006; 284:87-93. [PMID: 16541202 DOI: 10.1007/s11010-005-9018-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Accepted: 09/26/2005] [Indexed: 10/24/2022]
Abstract
In the present study we investigated whether acute glucose administration could be protective against hypoxic stress. H9c2 cells were exposed to either 4.5 mM or 22 mM of glucose for 15,min and then were submitted to simulated ischemia. Cell death was microscopically assessed by combined staining with propidium iodide (PI) and Hoeschst 33358. Intracellular content of glucose was measured by enzymatic analysis. Clucose content of H9c2 cells was 48.24+/- 7.94 micromol/L in the 22 mM vs 23.86+/- 4.8 micromol/L in the 4.5 mM group (p < 0.05). PKCepsilon expression was increased 1.6 fold in the membrane fraction after pretreatment with high glucose (p < 0.05), while was decreased 1.6 fold in the cytosol (p < 0.05). In addition, no difference to PKCdelta translocation was observed after pretreatment with low glucose. After hypoxia, in the 22 mM group, cell death was found to be 17.36+/- 2.66% vs 38.2+/- 5.4% in the 4.5 mM group (p < 0.05). In the presence of iodoacetic acid, a glycolytic inhibitor, cell death was not different between the two groups (23.54+/- 3.2% in 22 mM vs 22.06+/- 5.3% in 4.5 mM). Addition of chelerythrine did not change the protective effect of high glucose (13.4+/- 1.7% cell death in 22 mM vs 27.5+/- 5.5% in 4.5 mM, p < 0.05). In conclusion, short pretreatment with high glucose protects H9c2 cells against hypoxia. Although this protective effect is associated with translocation of PKCepsilon and increased glucose uptake, it was abrogated only by inhibition of glycolysis.
Collapse
Affiliation(s)
- Vassiliki Malliopoulou
- Department of Pharmacology, University of Athens, 75 Mikras Asias Ave., 11527 Goudi, Athens, Greece
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Chang PN, Mao JC, Huang SH, Ning L, Wang ZJ, On T, Duan W, Zhu YZ. Analysis of Cardioprotective Effects Using Purified Salvia miltiorrhiza Extract on Isolated Rat Hearts. J Pharmacol Sci 2006; 101:245-9. [PMID: 16837771 DOI: 10.1254/jphs.fpj05034x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
The purpose of the current study is to evaluate the cardioprotective effects of purified Salvia miltiorrhiza extract (PSME) on myocardial ischemia/reperfusion injury in isolated rat hearts. Hearts were excised and perfused at constant flow (7 - 9 ml.min(-1)) via the aorta. Non-recirculating perfusion with Krebs-Henseleit (KH) solution was maintained at 37 degrees C and continuously gassed with 95% O2 and 5% CO2. KH solution with or without PSME (100 mg per liter solution) was used after 30-min zero-flow ischemia for the PSME and control group, respectively. Left ventricular (LV) developed pressure; its derivatives, diastolic pressure, and so on were continuously recorded via a pressure transducer attached to a polyvinylchloride balloon that was placed in the left ventricle through an incision in the left atrium. PSME treated hearts showed significant postischemic contractile function recovery (developed pressure recovered to 44.2 +/- 4.9% versus 17.1 +/- 5.7%, P<0.05; maximum contraction recovered to 57.2 +/- 5.9% versus 15.1 +/- 6.3%, P<0.001; maximum relaxation restored to 69.3 +/- 7.3% versus 15.4 +/- 6.3%, P<0.001 in the PSME and control group, respectively). Significant elevation in end-diastolic pressure, which indicated LV stiffening in PSME hearts might have resulted from the excess high dose of PSME used. Further study will be conducted on the potential therapeutic value with lower dose of PSME on prevention of ischemic heart disease.
Collapse
Affiliation(s)
- Piek Ngoh Chang
- Department of Pharmacology, Faculty of Medicine, National University of Singapore, Singapore
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Kwak YL. Reduction of Ischemia During Off-Pump Coronary Artery Bypass Graft Surgery. J Cardiothorac Vasc Anesth 2005; 19:667-77. [PMID: 16202908 DOI: 10.1053/j.jvca.2005.04.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Indexed: 12/11/2022]
Affiliation(s)
- Young Lan Kwak
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemun-Ku, Seoul, Korea.
| |
Collapse
|
35
|
Visser L, Zuurbier CJ, Hoek FJ, Opmeer BC, de Jonge E, de Mol BAJM, van Wezel HB. Glucose, insulin and potassium applied as perioperative hyperinsulinaemic normoglycaemic clamp: effects on inflammatory response during coronary artery surgery. Br J Anaesth 2005; 95:448-57. [PMID: 16100235 DOI: 10.1093/bja/aei220] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The clinical benefits of glucose-insulin-potassium (GIK) and tight glycaemic control in patients undergoing coronary artery bypass grafting (CABG) may be partly explained by an anti-inflammatory effect. We applied GIK as a hyperinsulinaemic normoglycaemic clamp for >25 h and quantified its effect on systemic inflammation in patients undergoing CABG. METHODS Data obtained in 21 non-diabetic patients with normal left ventricular function scheduled for elective coronary artery surgery, who were randomly allocated to a control or GIK group, were analysed. In GIK patients, regular insulin was infused at a fixed rate of 0.1 IU kg(-1) h(-1). The infusion rate of glucose (30%) was adjusted to maintain blood glucose levels within a target range of 4.0-5.5 mmol litre(-1). Plasma concentrations of interleukins 6, 8 and 10, C-reactive protein (CRP) and serum amyloid A (SAA) were measured on the day of surgery and on the first and second postoperative days (POD1 and POD2). RESULTS In the GIK group hypoglycaemia (glucose <2.2 mmol litre(-1)) did not occur, whereas hyperglycemia (glucose >6.1 mmol litre(-1)) developed in 15% of all measurements. In control patients, hyperglycaemia developed in >80% of all measurements in the presence of low endogenous insulin levels. CRP and SAA levels increased in both groups, with maximum levels measured on POD2. GIK treatment significantly reduced CRP and SAA levels. Interleukin levels increased significantly in both groups following cardiopulmonary bypass, but no differences were found between the groups. CONCLUSION Hyperinsulinaemic normoglycaemic clamp is an effective method of maintaining tight glycaemic control in patients undergoing CABG and it attenuates the systemic inflammatory response in these patients. This effect may partly contribute to the reported beneficial effect of glycaemic control in patients undergoing CABG.
Collapse
Affiliation(s)
- L Visser
- Department of Anaesthesia, Academic Medical Center, University of Amsterdam, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
36
|
Koskenkari JK, Kaukoranta PK, Kiviluoma KT, Raatikainen MJP, Ohtonen PP, Ala-Kokko TI. Metabolic and Hemodynamic Effects of High-Dose Insulin Treatment in Aortic Valve and Coronary Surgery. Ann Thorac Surg 2005; 80:511-7. [PMID: 16039195 DOI: 10.1016/j.athoracsur.2005.03.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 02/28/2005] [Accepted: 03/04/2005] [Indexed: 11/18/2022]
Abstract
BACKGROUND Glucose and insulin have been used as an adjuvant therapy in cardiac surgery because of their potentially beneficial effects on myocardial metabolism and contractile function. This study evaluated the effects of high-dose insulin on systemic metabolism and hemodynamics after combined heart surgery. METHODS Forty elective patients scheduled for combined aortic valve replacement and coronary artery bypass surgery were randomly assigned to receive either high-dose insulin treatment (short-acting insulin 1 IU.kg(-1).h(-1) with 30% glucose 1.5 mL.kg(-1).h(-1) administered separately) or control treatment (saline). The blood glucose levels were maintained within a targeted range by adjusting the rate of glucose infusion in the treatment group and by short-acting insulin bolus doses in the control group. RESULTS The lactate clearance was faster (p = 0.046), and the lactate levels (p = 0.016), blood glucose levels (p < 0.001), and free fatty acid levels (p < 0.001) were lower in the insulin group postoperatively. Besides, there was lesser need for dobutamine support (p = 0.013) and a trend toward better cardiac indices. Insulin treatment increased the respiratory quotient (p < 0.001), but there were no differences between the groups with regard to systemic oxygen consumption or energy expenditure measured by indirect calorimetry. The average glucose uptake in the insulin group was 7.1 g/kg in 24 hours (28 kcal.kg(-1).day(-1)). CONCLUSIONS The high-dose insulin treatment was associated with lower blood glucose levels, better preserved myocardial contractile function, and less need for inotropic support, and hence led to lower lactate levels postoperatively. The protocol is safe, but requires strict control of blood glucose level.
Collapse
Affiliation(s)
- Juha K Koskenkari
- Division of Intensive Care, Department of Anesthesiology, University of Oulu, Oulu, Finland.
| | | | | | | | | | | |
Collapse
|
37
|
|
38
|
Gnaim CI, McGuire DK. Glucose-insulin-potassium therapy for acute myocardial infarction: what goes around comes around. Am Heart J 2004; 148:924-30. [PMID: 15632873 DOI: 10.1016/j.ahj.2004.09.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
39
|
Bothe W, Olschewski M, Beyersdorf F, Doenst T. Glucose-Insulin-Potassium in Cardiac Surgery: A Meta-Analysis. Ann Thorac Surg 2004; 78:1650-7. [PMID: 15511450 DOI: 10.1016/j.athoracsur.2004.03.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/29/2003] [Indexed: 01/04/2023]
Abstract
BACKGROUND Glucose-insulin-potassium therapy (GIK) has been suggested to reduce mortality and improve postoperative recovery after cardiac surgery. We performed a meta-analysis of all randomized studies using GIK in cardiac surgery. METHODS A systematic Medline search for all GIK studies in cardiac surgery was carried out. Randomized studies investigating the recovery of contractile function as a primary endpoint were included in the meta-analysis. RESULTS Thirty-five GIK trials were identified. Twenty-four studies were excluded because of lack of randomization, supplementary administration of other substances, or due to other primary endpoints. Eleven studies were included with a total of 468 patients who underwent either coronary artery bypass grafting or heart valve replacement. Six studies noted a significant improvement in postoperative recovery. One study demonstrated no effect. In four studies, no comparable statistical analysis was available. GIK patients required similar or lesser doses of catecholamines. From the available data we estimated a weighted mean of relative improvement in postoperative recovery of cardiac index for GIK patients versus controls of 11.4%. Five of 11 studies reported the incidence of postoperative atrial fibrillation (AF). AF occurred in 23% (20/86) in GIK versus 42% (36/86) in control patients (p = 0.009). CONCLUSIONS The findings indicate that GIK may considerably improve postoperative recovery of contractile function and reduce the incidence of atrial arrhythmias after cardiac surgery. However, several factors limit the power of this analysis and large, randomized multicenter trials are needed to fully assess the efficacy of GIK after cardiac surgery.
Collapse
Affiliation(s)
- Wolfgang Bothe
- Department of Cardiovascular Surgery, University of Freiburg, Freiburg, Germany
| | | | | | | |
Collapse
|
40
|
|
41
|
Houghton JL, Strogatz DS, Torosoff MT, Smith VE, Fein SA, Kuhner PA, Philbin EF, Carr AA. African Americans with LVH demonstrate depressed sensitivity of the coronary microcirculation to stimulated relaxation. Hypertension 2003; 42:269-76. [PMID: 12913059 DOI: 10.1161/01.hyp.0000087840.43329.01] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Excess coronary heart disease morbidity and mortality among African Americans remains an important yet unexplained public health problem. We hypothesized that adverse outcome is in part due to intrinsic or acquired abnormalities in coronary endothelial function and vasoreactivity. We compared dose-response curves relating changes in coronary blood flow and epicardial diameter to graded infusions of acetylcholine in 50 African American and 65 white subjects with hypertensive left ventricular hypertrophy (LVH) and normal coronary arteries. These groups were similar for age, body mass index, mean arterial pressure, and indexed left ventricular mass. The same protocol was conducted in 24 normotensive African American and 56 similar white subjects. We found significant depression in the coronary blood flow dose-response curve relation among African Americans when compared with white subjects with similar LVH (P<0.03). Racial differences were observed at all doses of acetylcholine but were less precisely estimated at the highest dose. The same testing among normotensive subjects revealed similar dose-response curves with no significant effect of race. Qualitatively similar results were found with respect to coronary diameter. Adenosine responses, a measure of endothelium-independent function, were similar after partitioning by LVH. Our study demonstrates that there are racial differences in sensitivity of coronary arteries to acetylcholine-stimulated relaxation among those with LVH. These results provide a mechanism whereby racial differences in coronary vasoreactivity might contribute to adverse coronary heart disease outcome among African Americans, a group in whom LVH is prevalent.
Collapse
Affiliation(s)
- Jan Laws Houghton
- Division of Cardiology, A-44, Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA.
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
Cardioplegia has become the gold standard of myocardial protection for practically every type of heart surgery during which the ascending aorta must be clamped. Although there is little doubt about the efficacy of cardioplegia in the adult heart, there are few studies on the pediatric heart and their results are contradictory. The physiology of pediatric heart muscle differs considerably from that of the adult myocardium. The pediatric heart distinguishes itself from that of the adult most impressively in its greater tolerance for ischemia. This ischemia tolerance is enhanced by the use of hypothermia. Considering that hypothermia is a powerful tool to prolong ischemia tolerance and that most pediatric cardiac surgeons report similar results using different types of cardioplegia, some surgeons are tempted to suspect that the contribution of the cardioplegia composition to protecting the pediatric heart may be overestimated. This provocative statement is critically discussed in this article. We examine the protective potential of cardioplegia (in various compositions), or of hypothermia, or of both in pediatric cardiac surgery. We pay special attention to several key differences between the physiologies of the pediatric myocardium and the adult myocardium and attempt to relate them to the available surgical methods of myocardial protection. We conclude that the composition of cardioplegia indeed is an important component of successful operative management in pediatric heart surgery. We provide evidence that the benefit of cardioplegia over hypothermia alone is minor at low temperatures (below 15 degrees C), but becomes substantial when the temperature increases.
Collapse
Affiliation(s)
- Torsten Doenst
- Department of Cardiovascular Surgery, Albert-Ludwigs University of Freiburg, Freiburg I Br, Germany.
| | | | | |
Collapse
|
43
|
Fadl YY, Zareba W, Moss AJ, Marder VJ, Sparks CS, Miller Watelet LF, Carroll ER. History of hypertension and enhanced thrombogenic activity in postinfarction patients. Hypertension 2003; 41:943-9. [PMID: 12629034 DOI: 10.1161/01.hyp.0000061120.23237.d9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hypertension is a risk factor for coronary thrombosis and death in cardiac patients mediated in part by endothelial damage or dysfunction and increased thrombogenicity. However, there are no data regarding the association between hypertension and thrombogenic activity in stable patients after myocardial infarction and limited data about the prognostic significance of thrombogenic factors in hypertensive patients after infarction. Therefore, levels of thrombogenic, lipid, and inflammatory factors were measured 2 months after an acute myocardial infarction in 461 hypertensive and 582 nonhypertensive patients. Thrombogenic factors included d-dimer, fibrinogen, plasminogen activator inhibitor-1, von Willebrand factor, factor VII, and factor VIIa. Lipid variables included cholesterol (total, HDL, LDL), triglyceride, lipoprotein (a), apolipoprotein-A1, and apolipoprotein-B. The prognostic significance of these factors for predicting cardiac events during a 2-year follow-up was evaluated in hypertensive and nonhypertensive patients. In comparison with nonhypertensive patients, those with hypertension had higher levels of d-dimer (607 versus 453 mg/L, P<0.001), fibrinogen (3.64 versus 3.43 g/L, P<0.001), plasminogen activator inhibitor-1 (29.7 versus 27.3 ng/mL, P=0.01), von Willebrand factor (159 versus 141 IU/dL; P<0.001), and higher levels of inflammatory markers (hsCRP and SAA). In multivariate analysis after adjustment for clinical covariates, elevated d-dimer was the only factor independently associated with a history of hypertension (OR, 1.38, P=0.05). d-Dimer was associated with an increased risk of recurrent cardiac events in both hypertensive (hazard ratio=3.02, P=0.005) and nonhypertensive (hazard ratio=2.42, P=0.02) patients. Thus, patients after infarction with a history of hypertension have enhanced thrombogenic activity, which predisposes them to recurrent cardiac events.
Collapse
Affiliation(s)
- Yazid Y Fadl
- Cardiology Unit, Department of Medicine, University of Rochester Medical Center, Box 653, Rochester, NY 14642, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
Taegtmeyer H. Improving Energy Metabolism in the Postischemic Heart-The Story of GIK. Semin Cardiothorac Vasc Anesth 2003. [DOI: 10.1177/108925320300700113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Heart muscle is a metabolic omnivore. The normal heart derives its energy for contraction from the oxidation of longchain fatty acids. The stressed heart switches to carbohydrate substrates for greater efficiency of energy production. Here we review the evidence for glucose-insulin-potassium as an effective strategy to treat postischemic contractile dysfunction of the heart. There is a strong rationale for both glucose and insulin to restore efficient energy transfer in the metabolically depleted postischemic heart. In spite ofits long history and abundant opportunities for translational research, the field is still in its infancy. Further progress is tied to two broad areas of research: randomized, multicenter clinical trialsand systematic studies addressing cellular signaling mechanisms, including nutrient sensing of myocardial gene expression.
Collapse
Affiliation(s)
- Heinrich Taegtmeyer
- The University of Texas Houston Medical School, Department of Internal Medicine, Division of Cardiology, 6431 Fannin, MSB 1.246, Houston, TX 77030
| |
Collapse
|
45
|
van Wezel HB, Jong SWMD. Clinical Use of Glucose-Insulin-Potassium in Cardiac Surgery andAcute Myocardial Infarction: An Overview. Semin Cardiothorac Vasc Anesth 2003. [DOI: 10.1177/108925320300700114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Harry B. van Wezel
- Department of Anesthesiology, Academic Medical Center, Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | | |
Collapse
|
46
|
Abstract
Insulin has been used in the treatment of patients undergoing cardiac surgery or suffering from acute myocardial infarction. Most of these investigations have demonstrated that the metabolic cocktail consisting of glucose-insulin-potassium (GIK) improves recovery of function and outcome after cardiac surgery and substantially reduces mortality of patients with acute myocardial infarction. There is also evidence suggesting that insulin is not effective under these conditions, as demonstrated in a recent large randomized trial in cardiac surgery. It is therefore not surprising that insulin or GIK is not used routinely in clinical practice. Many hypotheses have been advanced to explain the effects of insulin and GIK but none of them has enjoyed convincing support. In cardiac surgery the many different application protocols described make it difficult to compare the results. The application of GIK after cardiac surgery may be complicated by severe disturbances in glucose or potassium homeostasis. In this article we review the literature in this field, addressing the areas of controversy. We discuss the different mechanisms suggested and we propose potential solutions. We conclude that a multifactorial mechanism is likely to explain the effects of insulin or GIK after ischemia and we propose that in a practical sense the application of high-dose insulin during reperfusion, utilizing a newly described, direct nonmetabolic effect, is a convincing concept. We will further demonstrate our clinical experience in establishing a protocol for putting this concept into clinical practice.
Collapse
Affiliation(s)
- Torsten Doenst
- Department of Cardiovascular Surgery, Albert Ludwigs University of Freiburg, Freiburg, Germany.
| | | | | |
Collapse
|
47
|
van Wezel HB, de Jong SWM. Glucose, Free Fatty Acids, and Insulin Following Acute Myocardial Ischemia. Intensive Care Med 2003. [DOI: 10.1007/978-1-4757-5548-0_40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
48
|
Angelos MG, Murray HN, Gorsline RT, Klawitter PF. Glucose, insulin and potassium (GIK) during reperfusion mediates improved myocardial bioenergetics. Resuscitation 2002; 55:329-36. [PMID: 12458070 DOI: 10.1016/s0300-9572(02)00215-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Previous studies suggest glucose, insulin and potassium (GIK) infusion during ischemia reduces infarct size and improves post-ischemic myocardial function in acute myocardial infarction and following surgical revascularization of the heart. The potential use of GIK when given only during reperfusion after a period of global ischemia, as might occur during cardiac arrest, is unclear. To test the hypothesis that GIK reperfusion improves post-ischemic myocardial bioenergetics and function, we utilized a perfused heart model. Hearts from Sprague-Dawley rats (350-450 g) were perfused at 85 mmHg with oxygenated Krebs-Henseleit bicarbonate containing 5.5 mM glucose and 0.2 mM octanoic acid. Following 20 min of global ischemia, hearts were reperfused for 30 min with original solution (control) or GIK in two different doses (10 or 20 mM glucose each with insulin 10 U/l and K(+) 7 meq/l). Hearts perfused with GIK solutions had significantly higher ATP, creatine phosphate, energy charge, and NADP(+) and lower AMP and inosine levels compared with control after 30 min of reperfusion. Hearts reperfused with GIK had significantly higher developed pressure and higher dP/dt than control reperfused hearts. Reperfusion with GIK improved post-ischemic recovery of both contractile function and the myocardial bioenergetic state. GIK may be a viable adjunctive reperfusion therapy following the global ischemia of cardiac arrest to improve post-resuscitation cardiac dysfunction.
Collapse
Affiliation(s)
- Mark G Angelos
- Department of Emergency Medicine, The Ohio State University, 016 Prior Health Sciences Library, 376 West Tenth Avenue, Columbus 43210-1270, USA.
| | | | | | | |
Collapse
|
49
|
Imura H, Ayres BE, Suleiman MS. Purine metabolism and release during cardioprotection with hyperkalemia and hypothermia. Mol Cell Biochem 2002; 237:119-27. [PMID: 12236579 DOI: 10.1023/a:1016551720672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work investigates whether purine metabolism and release is related to cardioprotection with hyperkalemia and hypothermia. Langendorff guinea-pig hearts were used to either monitor metabolism during ischemia or to measure functional recovery, myocardial injury and release of purine during reperfusion. Hearts underwent 30 min ischemia using one of the following protocols: control (normothermic buffer), hyperkalaemia (high-potassium buffer), hypothermia (20 degrees C) and hyperkalemia + hypothermia. At the end of 30 min ischemia, hyperkalemia was associated with similar metabolic changes (rise in purine and lactate and fall in adenine nucleotides) to control group. Accumulation of purine was due to a rise in inosine, xanthine and hypoxanthine and was largely prevented by hypothermia and hyperkalemia + hypothermia. Upon reperfusion, there was a time-dependent release of all purine, lactate and AMP. A fast (peak in less than 20 sec) release of inosine, xanthine, hypoxanthine and lactate was highest in control followed by hyperkalemia then hypothermia and little release in hyperkalemia + hypothermia. Adenosine and AMP release was slow (peak at 3 min), only significant in control and was likely to be due to sarcolemmal disruption as the profile followed lactate dehydrogenase release. Recovery (left ventricular developed pressure) was 63% control, 82% hyperkalemia, 77% hypothermia and 98% for hyperkalemia + hypothermia. The loss of purine during reperfusion but not their production during ischemia is related to cardioprotection with hyperkalemia. The possibility that the consequences of hyperkalemia modulate a sodium-dependent purine efflux, is discussed. The reduced loss of purine in hypothermia or in hyperkalemia + hypothermia is likely to be due to a lower metabolic activity during ischemia.
Collapse
|
50
|
Ziegler A, Zaugg CE, Buser PT, Seelig J, Künnecke B. Non-invasive measurements of myocardial carbon metabolism using in vivo 13C NMR spectroscopy. NMR IN BIOMEDICINE 2002; 15:222-234. [PMID: 11968138 DOI: 10.1002/nbm.764] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Despite their prime role in maintaining contractile performance, myocardial substrate uptake, substrate preference and metabolism are difficult to assess non-invasively. The objective of the present work was to extend the scope of cardiac 13C nuclear magnetic resonance (NMR) spectroscopy to the in vivo situation ('closed-chest model') and to quantitatively appraise myocardial metabolism in vivo. For this purpose, overnight-fasted Sprague-Dawley rats received intravenous infusions of non-radioactive 13C-labeled glucose, 3-hydroxybutyrate, and acetate as markers for glycolysis, metabolism of ketone bodies and direct incorporation into tricarboxylic acid (TCA) cycle, respectively. In vivo 13C NMR spectra (at 7 T) were acquired from the myocardium with a time resolution of 6 min. At the end of the infusion experiments, tissue extracts were prepared and further analyzed by high-resolution 13C NMR spectroscopy in order to corroborate the findings obtained in vivo. Accordingly, 3-hydroxybutyrate and acetate were rapidly extracted by the myocardium and supplied 42 +/- 6 and 53 +/- 9% of the acetyl-CoA for TCA cycle operation, whereas glucose, although also well extracted, did not contribute to myocardial oxidative metabolism. Myocardial TCA cycle turnover (V(TCA)) in vivo was estimated at 1.34 +/- 0.07 micromol/min/g wet weight, myocardial oxygen consumption (MVO2) at 2.95 +/- 0.16 micromol/min/g wet weight, exchange rate between alpha-ketoglutarate and glutamate (V(x)) at 1.22 +/- 0.08 micromol/min/g wet weight and rate of glutamine synthesis (V(gln)) at 0.14 +/- 0.02 micromol/min/g wet weight. The substantial synthesis of myocardial glutamine is in contrast to experiments with isolated and saline perfused hearts. In conclusion, it is demonstrated that 13C NMR spectroscopy of the heart in intact rats is feasible and provides new quantitative insight into myocardial substrate uptake, preference and metabolism in vivo.
Collapse
Affiliation(s)
- André Ziegler
- Department of Biophysical Chemistry, Biozentrum, University of Basel, Switzerland
| | | | | | | | | |
Collapse
|