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Berndt N, Eckstein J, Wallach I, Nordmeyer S, Kelm M, Kirchner M, Goubergrits L, Schafstedde M, Hennemuth A, Kraus M, Grune T, Mertins P, Kuehne T, Holzhütter HG. CARDIOKIN1: Computational Assessment of Myocardial Metabolic Capability in Healthy Controls and Patients With Valve Diseases. Circulation 2021; 144:1926-1939. [PMID: 34762513 PMCID: PMC8663543 DOI: 10.1161/circulationaha.121.055646] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Many heart diseases can result in reduced pumping capacity of the heart muscle. A mismatch between ATP demand and ATP production of cardiomyocytes is one of the possible causes. Assessment of the relation between myocardial ATP production (MVATP) and cardiac workload is important for better understanding disease development and choice of nutritional or pharmacologic treatment strategies. Because there is no method for measuring MVATP in vivo, the use of physiology-based metabolic models in conjunction with protein abundance data is an attractive approach. METHOD: We developed a comprehensive kinetic model of cardiac energy metabolism (CARDIOKIN1) that recapitulates numerous experimental findings on cardiac metabolism obtained with isolated cardiomyocytes, perfused animal hearts, and in vivo studies with humans. We used the model to assess the energy status of the left ventricle of healthy participants and patients with aortic stenosis and mitral valve insufficiency. Maximal enzyme activities were individually scaled by means of protein abundances in left ventricle tissue samples. The energy status of the left ventricle was quantified by the ATP consumption at rest (MVATP[rest]), at maximal workload (MVATP[max]), and by the myocardial ATP production reserve, representing the span between MVATP(rest) and MVATP(max). Results: Compared with controls, in both groups of patients, MVATP(rest) was increased and MVATP(max) was decreased, resulting in a decreased myocardial ATP production reserve, although all patients had preserved ejection fraction. The variance of the energetic status was high, ranging from decreased to normal values. In both patient groups, the energetic status was tightly associated with mechanic energy demand. A decrease of MVATP(max) was associated with a decrease of the cardiac output, indicating that cardiac functionality and energetic performance of the ventricle are closely coupled. Conclusions: Our analysis suggests that the ATP-producing capacity of the left ventricle of patients with valvular dysfunction is generally diminished and correlates positively with mechanical energy demand and cardiac output. However, large differences exist in the energetic state of the myocardium even in patients with similar clinical or image-based markers of hypertrophy and pump function. Registration: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT03172338 and NCT04068740.
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Affiliation(s)
- Nikolaus Berndt
- Institute of Computer-assisted Cardiovascular Medicine, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Johannes Eckstein
- Institute of Computer-assisted Cardiovascular Medicine, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Institute of Biochemistry, Charitá - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Iwona Wallach
- Institute of Computer-assisted Cardiovascular Medicine, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Institute of Biochemistry, Charitá - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Sarah Nordmeyer
- Institute of Computer-assisted Cardiovascular Medicine, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Department of Congenital Heart Disease - Pediatric Cardiology, Deutsches Herzzentrum Berlin (DHZB), Berlin, Germany
| | - Marcus Kelm
- Institute of Computer-assisted Cardiovascular Medicine, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Department of Congenital Heart Disease - Pediatric Cardiology, Deutsches Herzzentrum Berlin (DHZB), Berlin, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung e. V. (DZHK), Berlin, Germany; Berlin Institute of Health (BIH), Berlin, Germany
| | - Marieluise Kirchner
- Berlin Institute of Health (BIH), Berlin, Germany; Proteomics Platform, Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| | - Leonid Goubergrits
- Institute of Computer-assisted Cardiovascular Medicine, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Einstein Center Digital Future, Berlin, Germany
| | - Marie Schafstedde
- Institute of Computer-assisted Cardiovascular Medicine, Charité; Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Department of Congenital Heart Disease - Pediatric Cardiology, Deutsches Herzzentrum Berlin (DHZB), Berlin, Germany; Berlin Institute of Health (BIH), Berlin, Germany
| | - Anja Hennemuth
- Institute of Computer-assisted Cardiovascular Medicine, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Milena Kraus
- Digital Health Center, Hasso Plattner Institute, University of Potsdam, Germany
| | - Tilman Grune
- Deutsches Zentrum für Herz-Kreislauf-Forschung e. V. (DZHK), Berlin, Germany; Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Nuthetal, Germany
| | - Philipp Mertins
- Berlin Institute of Health (BIH), Berlin, Germany; Proteomics Platform, Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
| | - Titus Kuehne
- Institute of Computer-assisted Cardiovascular Medicine, Charité; Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Department of Congenital Heart Disease - Pediatric Cardiology, Deutsches Herzzentrum Berlin (DHZB), Berlin, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung e. V. (DZHK), Berlin, Germany
| | - Hermann-Georg Holzhütter
- Institute of Biochemistry, Charitá - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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Ho KL, Karwi QG, Wagg C, Zhang L, Vo K, Altamimi T, Uddin GM, Ussher JR, Lopaschuk GD. Ketones can become the major fuel source for the heart but do not increase cardiac efficiency. Cardiovasc Res 2021; 117:1178-1187. [PMID: 32402081 PMCID: PMC7982999 DOI: 10.1093/cvr/cvaa143] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 04/16/2020] [Accepted: 05/07/2020] [Indexed: 12/18/2022] Open
Abstract
AIMS Ketones have been proposed to be a 'thrifty' fuel for the heart and increasing cardiac ketone oxidation can be cardioprotective. However, it is unclear how much ketone oxidation can contribute to energy production in the heart, nor whether increasing ketone oxidation increases cardiac efficiency. Therefore, our goal was to determine to what extent high levels of the ketone body, β-hydroxybutyrate (βOHB), contributes to cardiac energy production, and whether this influences cardiac efficiency. METHODS AND RESULTS Isolated working mice hearts were aerobically perfused with palmitate (0.8 mM or 1.2 mM), glucose (5 mM) and increasing concentrations of βOHB (0, 0.6, 2.0 mM). Subsequently, oxidation of these substrates, cardiac function, and cardiac efficiency were assessed. Increasing βOHB concentrations increased myocardial ketone oxidation rates without affecting glucose or fatty acid oxidation rates where normal physiological levels of glucose (5 mM) and fatty acid (0.8 mM) are present. Notably, ketones became the major fuel source for the heart at 2.0 mM βOHB (at both low or high fatty acid concentrations), with the elevated ketone oxidation rates markedly increasing tricarboxylic acid (TCA) cycle activity, producing a large amount of reducing equivalents and finally, increasing myocardial oxygen consumption. However, the marked increase in ketone oxidation at high concentrations of βOHB was not accompanied by an increase in cardiac work, suggesting that a mismatch between excess reduced equivalents production from ketone oxidation and cardiac adenosine triphosphate production. Consequently, cardiac efficiency decreased when the heart was exposed to higher ketone levels. CONCLUSIONS We demonstrate that while ketones can become the major fuel source for the heart, they do not increase cardiac efficiency, which also underscores the importance of recognizing ketones as a major fuel source for the heart in times of starvation, consumption of a ketogenic diet or poorly controlled diabetes.
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Affiliation(s)
- Kim L Ho
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Qutuba G Karwi
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
- Department of Pharmacology, College of Medicine, University of Diyala, Diyala, Iraq
| | - Cory Wagg
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Liyan Zhang
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Katherina Vo
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Tariq Altamimi
- Diabetes and Obesity Center, University of Louisville, Louisville, KT, USA
| | - Golam M Uddin
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - John R Ussher
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Gary D Lopaschuk
- Cardiovascular Research Centre Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
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Karwi QG, Lopaschuk GD. CrossTalk proposal: Ketone bodies are an important metabolic fuel for the heart. J Physiol 2021; 600:1001-1004. [PMID: 33645632 DOI: 10.1113/jp281004] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Qutuba G Karwi
- Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada.,Department of Pharmacology, College of Medicine, University of Diyala, Diyala, Iraq
| | - Gary D Lopaschuk
- Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada
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Lopaschuk GD, Karwi QG, Ho KL, Pherwani S, Ketema EB. Ketone metabolism in the failing heart. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158813. [PMID: 32920139 DOI: 10.1016/j.bbalip.2020.158813] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/26/2020] [Accepted: 09/05/2020] [Indexed: 12/13/2022]
Abstract
The high energy demands of the heart are met primarily by the mitochondrial oxidation of fatty acids and glucose. However, in heart failure there is a decrease in cardiac mitochondrial oxidative metabolism and glucose oxidation that can lead to an energy starved heart. Ketone bodies are readily oxidized by the heart, and can provide an additional source of energy for the failing heart. Ketone oxidation is increased in the failing heart, which may be an adaptive response to lessen the severity of heart failure. While ketone have been widely touted as a "thrifty fuel", increasing ketone oxidation in the heart does not increase cardiac efficiency (cardiac work/oxygen consumed), but rather does provide an additional fuel source for the failing heart. Increasing ketone supply to the heart and increasing mitochondrial ketone oxidation increases mitochondrial tricarboxylic acid cycle activity. In support of this, increasing circulating ketone by iv infusion of ketone bodies acutely improves heart function in heart failure patients. Chronically, treatment with sodium glucose co-transporter 2 inhibitors, which decreases the severity of heart failure, also increases ketone body supply to the heart. While ketogenic diets increase circulating ketone levels, minimal benefit on cardiac function in heart failure has been observed, possibly due to the fact that these dietary regimens also markedly increase circulating fatty acids. Recent studies, however, have suggested that administration of ketone ester cocktails may improve cardiac function in heart failure. Combined, emerging data suggests that increasing cardiac ketone oxidation may be a therapeutic strategy to treat heart failure.
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Affiliation(s)
- Gary D Lopaschuk
- Cardiovascular Research Centre, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
| | - Qutuba G Karwi
- Cardiovascular Research Centre, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Department of Pharmacology, College of Medicine, University of Diyala, Diyala, Iraq
| | - Kim L Ho
- Cardiovascular Research Centre, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Simran Pherwani
- Cardiovascular Research Centre, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Ezra B Ketema
- Cardiovascular Research Centre, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
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5
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Wentz AE, d'Avignon DA, Weber ML, Cotter DG, Doherty JM, Kerns R, Nagarajan R, Reddy N, Sambandam N, Crawford PA. Adaptation of myocardial substrate metabolism to a ketogenic nutrient environment. J Biol Chem 2010; 285:24447-56. [PMID: 20529848 DOI: 10.1074/jbc.m110.100651] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Heart muscle is metabolically versatile, converting energy stored in fatty acids, glucose, lactate, amino acids, and ketone bodies. Here, we use mouse models in ketotic nutritional states (24 h of fasting and a very low carbohydrate ketogenic diet) to demonstrate that heart muscle engages a metabolic response that limits ketone body utilization. Pathway reconstruction from microarray data sets, gene expression analysis, protein immunoblotting, and immunohistochemical analysis of myocardial tissue from nutritionally modified mouse models reveal that ketotic states promote transcriptional suppression of the key ketolytic enzyme, succinyl-CoA:3-oxoacid CoA transferase (SCOT; encoded by Oxct1), as well as peroxisome proliferator-activated receptor alpha-dependent induction of the key ketogenic enzyme HMGCS2. Consistent with reduction of SCOT, NMR profiling demonstrates that maintenance on a ketogenic diet causes a 25% reduction of myocardial (13)C enrichment of glutamate when (13)C-labeled ketone bodies are delivered in vivo or ex vivo, indicating reduced procession of ketones through oxidative metabolism. Accordingly, unmetabolized substrate concentrations are higher within the hearts of ketogenic diet-fed mice challenged with ketones compared with those of chow-fed controls. Furthermore, reduced ketone body oxidation correlates with failure of ketone bodies to inhibit fatty acid oxidation. These results indicate that ketotic nutrient environments engage mechanisms that curtail ketolytic capacity, controlling the utilization of ketone bodies in ketotic states.
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Affiliation(s)
- Anna E Wentz
- Department of Medicine, Washington University, St Louis, Missouri 63108, USA
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Regulation of myocardial ketone body metabolism by the gut microbiota during nutrient deprivation. Proc Natl Acad Sci U S A 2009; 106:11276-81. [PMID: 19549860 DOI: 10.1073/pnas.0902366106] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Studies in mice indicate that the gut microbiota promotes energy harvest and storage from components of the diet when these components are plentiful. Here we examine how the microbiota shapes host metabolic and physiologic adaptations to periods of nutrient deprivation. Germ-free (GF) mice and mice who had received a gut microbiota transplant from conventionally raised donors were compared in the fed and fasted states by using functional genomic, biochemical, and physiologic assays. A 24-h fast produces a marked change in gut microbial ecology. Short-chain fatty acids generated from microbial fermentation of available glycans are maintained at higher levels compared with GF controls. During fasting, a microbiota-dependent, Ppar alpha-regulated increase in hepatic ketogenesis occurs, and myocardial metabolism is directed to ketone body utilization. Analyses of heart rate, hydraulic work, and output, mitochondrial morphology, number, and respiration, plus ketone body, fatty acid, and glucose oxidation in isolated perfused working hearts from GF and colonized animals (combined with in vivo assessments of myocardial physiology) revealed that the fasted GF heart is able to sustain its performance by increasing glucose utilization, but heart weight, measured echocardiographically or as wet mass and normalized to tibial length or lean body weight, is significantly reduced in both fasted and fed mice. This myocardial-mass phenotype is completely reversed in GF mice by consumption of a ketogenic diet. Together, these results illustrate benefits provided by the gut microbiota during periods of nutrient deprivation, and emphasize the importance of further exploring the relationship between gut microbes and cardiovascular health.
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Abstract
At present the prevalence of heart failure rises along with aging of the population. Current heart failure therapeutic options are directed towards disease prevention via neurohormonal antagonism (β-blockers, angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers and aldosterone antagonists), symptomatic treatment with diuretics and digitalis and use of biventricular pacing and defibrillators in a special subset of patients. Despite these therapies and device interventions heart failure remains a progressive disease with high mortality and morbidity rates. The number of patients who survive to develop advanced heart failure is increasing. These patients require new therapeutic strategies. In this review two of emerging therapies in the treatment of heart failure are discussed: metabolic modulation and cellular therapy. Metabolic modulation aims to optimize the myocardial energy utilization via shifting the substrate utilization from free fatty acids to glucose. Cellular therapy on the other hand has the goal to achieve true cardiac regeneration. We review the experimental data that support these strategies as well as the available pharmacological agents for metabolic modulation and clinical application of cellular therapy.
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Affiliation(s)
- Diana Revenco
- Division of Cardiovascular Medicine, Caritas St. Elizabeth's Medical Center, Boston, MA 02135, USA
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8
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Tsai YC, Chou YC, Wu AB, Hu CM, Chen CY, Chen FA, Lee JA. Stereoselective effects of 3-hydroxybutyrate on glucose utilization of rat cardiomyocytes. Life Sci 2006; 78:1385-91. [PMID: 16225892 DOI: 10.1016/j.lfs.2005.07.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 07/11/2005] [Indexed: 11/16/2022]
Abstract
In researches of ketone bodies, D-3-hydroxybutyrate (D-3HB) is usually the major one which has been investigated; in contrast, little attention has been paid to L-3-hydroxybutyrate (L-3HB), because of its presence in trace amounts, its dubious metabolism, and a lack of knowledge about its sources. In the present study we determined the distributions of enantiomers of 3-hydroxybutyrate (3HB) in rat brain, liver, heart, and kidney homogenates, and we found the heart homogenate contained an enriched amount of L-3HB (37.67 microM/mg protein) which generated a significant ratio of 66/34 (D/L). The ratio was altered to be 87/13 in the diabetic rat heart homogenate. We subsequently found this changed ratio of D/L-3HB may contribute to reduce glucose utilization in cardiomyocytes. Glucose utilization by cardiomyocytes with 5 mM of D-3HB was decreased to 61% of the control, but no interference was observed when D-3HB was replaced with L-3HB, suggesting L-3HB is not utilized for the energy fuel as other ketone bodies are. In addition, the reduced glucose utilization caused by D-3HB gradually recovered in a dose-dependent manner with administration of additional L-3HB. The results gave the necessity of taking L-3HB together with D-3HB into account with regard to glucose utilization, and L-3HB may be a helpful substrate for improving inhibited cardiac pyruvate oxidation caused by hyperketonemia.
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Affiliation(s)
- Yih-Chiao Tsai
- Department of Pharmaceutical Analysis, School of Pharmacy, Taipei Medical University, No. 250, Wu-Hsing St., Taipei 11031, Taiwan, ROC
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9
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Stanley WC, Recchia FA, Lopaschuk GD. Myocardial substrate metabolism in the normal and failing heart. Physiol Rev 2005; 85:1093-129. [PMID: 15987803 DOI: 10.1152/physrev.00006.2004] [Citation(s) in RCA: 1392] [Impact Index Per Article: 73.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The alterations in myocardial energy substrate metabolism that occur in heart failure, and the causes and consequences of these abnormalities, are poorly understood. There is evidence to suggest that impaired substrate metabolism contributes to contractile dysfunction and to the progressive left ventricular remodeling that are characteristic of the heart failure state. The general concept that has recently emerged is that myocardial substrate selection is relatively normal during the early stages of heart failure; however, in the advanced stages there is a downregulation in fatty acid oxidation, increased glycolysis and glucose oxidation, reduced respiratory chain activity, and an impaired reserve for mitochondrial oxidative flux. This review discusses 1) the metabolic changes that occur in chronic heart failure, with emphasis on the mechanisms that regulate the changes in the expression of metabolic genes and the function of metabolic pathways; 2) the consequences of these metabolic changes on cardiac function; 3) the role of changes in myocardial substrate metabolism on ventricular remodeling and disease progression; and 4) the therapeutic potential of acute and long-term manipulation of cardiac substrate metabolism in heart failure.
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Affiliation(s)
- William C Stanley
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Ohio 44106-4970, USA.
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Stanley WC, Meadows SR, Kivilo KM, Roth BA, Lopaschuk GD. beta-Hydroxybutyrate inhibits myocardial fatty acid oxidation in vivo independent of changes in malonyl-CoA content. Am J Physiol Heart Circ Physiol 2003; 285:H1626-31. [PMID: 12969881 DOI: 10.1152/ajpheart.00332.2003] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study tested the hypothesis that an acute infusion of beta-hydroxybutyrate inhibits myocardial fatty acid uptake and oxidation in vivo. Anesthetized pigs were untreated (n = 6) or treated with an intravenous infusion of fat emulsion (n = 7) to elevate plasma free fatty acid levels. A third group received fat emulsion plus an intravenous infusion of beta-hydroxybutyrate (25 micromol.kg-1.min-1; n = 7) for 60 min. All animals received a continuous infusion of [3H]palmitate, and myocardial fatty acid oxidation was measured from the cardiac production of 3H2O. Plasma free fatty acid concentrations were elevated in the fat emulsion group (0.77 +/- 0.11 mM) compared with the untreated group (0.15 +/- 0.03 mM), which resulted in greater myocardial free fatty acid oxidation. In contrast, the group receiving beta-hydroxybutyrate in addition to fat emulsion had elevated beta-hydroxybutyrate concentration (0.87 +/- 0.11 vs. 0.04 +/- 0.01 mM), but suppressed fatty acid oxidation (0.053 +/- 0.013 micromol.g-1.min-1) (P < 0.05) compared with the fat emulsion group (0.116 +/- 0.029 micromol.g-1.min-1). There were no differences among the three groups in the tissue content for malonyl-CoA, acetyl-CoA, or free CoA or the activity of acetyl-CoA carboxylase; thus the inhibition of fatty acid oxidation by elevated beta-hydroxybutyrate did not appear to be due to malonyl-CoA inhibition of carnitine palmitoyl transferase-I or to an increase in the acetyl-CoA-to-free CoA ratio. In conclusion, fatty acid uptake and oxidation is blocked by an infusion of beta-hydroxybutyrate; this effect was not due to elevated myocardial malonyl-CoA content.
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Affiliation(s)
- William C Stanley
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4970, USA.
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Sultan AM. The effects of anaplerotic substrates on D-3-hydroxybutyrate metabolism in the heart. Mol Cell Biochem 1997; 171:59-64. [PMID: 9201696 DOI: 10.1023/a:1006865627489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this study the effects of propionate, L-valine, L-isoleucine, and DL-methionine on the metabolism of D-3-hydroxybutyrate (D-3-HB) were investigated in the isolated perfused non-working rat heart. Propionate inhibited the utilization (the total removal of D-3-HB by the heart) but stimulated the oxidation of D-3-HB. The degree of D-3-HB inhibition was dependent on the concentrations of propionate and D-3-HB. Furthermore, increasing the concentration of DL-hydroxybutyrate (DL-3-HB) to 16 or 30 mM abolished the inhibitory effect of propionate (4 mM). Whereas increasing the perfusion pressure from 40-80 mmHg stimulated the utilization and the oxidation of D-3-HB; propionate (4 mM) severely inhibited the utilization of D-3-HB at 40 and 80 mmHg, when DL-3-HB was 5 mM. On the other hand insulin (2 mU .ml-1) stimulated the utilization and the oxidation of D-3-HB at perfusion pressure of 40 mmHg, but showed no effect at 80 mmHg. Insulin was unable to overcome the inhibitory effect of propionate. Propionate improved the oxidation but inhibited the utilization of D-3-HB, while L-valine and L-isoleucine showed no effects on the utilization and the oxidation of D-3-HB. DL-methionine increased the utilization of D-3-HB by 14% without noticeable effects on the oxidation of D-3-HB. None of these anaplerotic substrates were suitable to ameliorate the utilization of D-3-HB.
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Affiliation(s)
- A M Sultan
- Department of Medical Sciences, Faculty of Medicine and Medical Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
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Sultan AMN, Khan ZA. The impact of physiological insulin concentration and depletion on the metabolism of glucose, endogenous glycogen, and triglycerides in the isolated perfused heart. Biochem Cell Biol 1997. [DOI: 10.1139/o97-035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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