1
|
Zhu XH, Chen W. Quantitative 17 O MRSI of myocardial oxygen metabolic rate, blood flow, and oxygen extraction fraction under normal and high workload conditions. Magn Reson Med 2024; 91:1645-1658. [PMID: 38084378 PMCID: PMC11089813 DOI: 10.1002/mrm.29908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/05/2023] [Accepted: 10/12/2023] [Indexed: 02/03/2024]
Abstract
PURPOSE The heart is a highly aerobic organ consuming most of the oxygen the body in supporting heart function. Quantitative imaging of myocardial oxygen metabolism and perfusion is essential for studying cardiac physiopathology in vivo. Here, we report a new imaging method that can simultaneously assess myocardial oxygen metabolism and blood flow in the rat heart. METHODS This novel method is based on the 17 O-MRSI combined with brief inhalation of 17 O-isotope labeled oxygen gas for quantitative imaging of myocardial metabolic rate of oxygen consumption (MVO2 ), myocardial blood flow (MBF), and oxygen extraction fraction (OEF). We demonstrate this imaging method under basal and high workload conditions in rat hearts at 9.4 T. RESULTS We show that this 17 O MRSI-based approach can directly measure and image MVO2 (1.35-4.06 μmol/g/min), MBF (0.49-1.38 mL/g/min), and OEF (0.33-0.44) in the heart of anesthetized rat under basal and high workload (21.6 × 103 -56.7 × 103 mmHg • bpm) conditions. Under high workload condition, MVO2 and MBF values in healthy rats approximately doubled, whereas OEF remained unchanged, indicating a strong coupling between myocardial oxygen metabolic demand and supply through blood perfusion. CONCLUSION The 17 O-MRSI method has been used to simultaneously image the myocardial metabolic rate of oxygen consumption, blood flow, and oxygen extraction fraction in small animal hearts, which are sensitive to the physiological changes induced by high workload. This approach could provide comprehensive measures that are critical for studying myocardial function in normal and diseased states and has a potential for translation.
Collapse
Affiliation(s)
- Xiao-Hong Zhu
- Center for Magnetic Resonance Research, Radiology Department, University of Minnesota, Minneapolis, Minnesota, USA
| | - Wei Chen
- Center for Magnetic Resonance Research, Radiology Department, University of Minnesota, Minneapolis, Minnesota, USA
| |
Collapse
|
2
|
Lopez-Schenk R, Collins NL, Schenk NA, Beard DA. Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism. Compr Physiol 2023; 14:5345-5369. [PMID: 38158366 PMCID: PMC10956446 DOI: 10.1002/cphy.c230011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Purine nucleotides play central roles in energy metabolism in the heart. Most fundamentally, the free energy of hydrolysis of the adenine nucleotide adenosine triphosphate (ATP) provides the thermodynamic driving force for numerous cellular processes including the actin-myosin crossbridge cycle. Perturbations to ATP supply and/or demand in the myocardium lead to changes in the homeostatic balance between purine nucleotide synthesis, degradation, and salvage, potentially affecting myocardial energetics and, consequently, myocardial mechanics. Indeed, both acute myocardial ischemia and decompensatory remodeling of the myocardium in heart failure are associated with depletion of myocardial adenine nucleotides and with impaired myocardial mechanical function. Yet there remain gaps in the understanding of mechanistic links between adenine nucleotide degradation and contractile dysfunction in heart disease. The scope of this article is to: (i) review current knowledge of the pathways of purine nucleotide depletion and salvage in acute ischemia and in chronic heart disease; (ii) review hypothesized mechanisms linking myocardial mechanics and energetics with myocardial adenine nucleotide regulation; and (iii) highlight potential targets for treating myocardial metabolic and mechanical dysfunction associated with these pathways. It is hypothesized that an imbalance in the degradation, salvage, and synthesis of adenine nucleotides leads to a net loss of adenine nucleotides in both acute ischemia and under chronic high-demand conditions associated with the development of heart failure. This reduction in adenine nucleotide levels results in reduced myocardial ATP and increased myocardial inorganic phosphate. Both of these changes have the potential to directly impact tension development and mechanical work at the cellular level. © 2024 American Physiological Society. Compr Physiol 14:5345-5369, 2024.
Collapse
Affiliation(s)
- Rachel Lopez-Schenk
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicole L Collins
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Noah A Schenk
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Daniel A Beard
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|
3
|
Vinnakota KC, Bazil JN, Van den Bergh F, Wiseman RW, Beard DA. Feedback Regulation and Time Hierarchy of Oxidative Phosphorylation in Cardiac Mitochondria. Biophys J 2016; 110:972-80. [PMID: 26910434 DOI: 10.1016/j.bpj.2016.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 12/27/2015] [Accepted: 01/04/2016] [Indexed: 11/18/2022] Open
Abstract
To determine how oxidative ATP synthesis is regulated in the heart, the responses of cardiac mitochondria oxidizing pyruvate to alterations in [ATP], [ADP], and inorganic phosphate ([Pi]) were characterized over a range of steady-state levels of extramitochondrial [ATP], [ADP], and [Pi]. Evolution of the steady states of the measured variables with the flux of respiration shows that: (1) a higher phosphorylation potential is achieved by mitochondria at higher [Pi] for a given flux of respiration; (2) the time hierarchy of oxidative phosphorylation is given by phosphorylation subsystem, electron transport chain, and substrate dehydrogenation subsystems listed in increasing order of their response times; (3) the matrix ATP hydrolysis mass action ratio [ADP] × [Pi]/[ATP] provides feedback to the substrate dehydrogenation flux over the entire range of respiratory flux examined in this study; and finally, (4) contrary to previous models of regulation of oxidative phosphorylation, [Pi] does not modulate the activity of complex III.
Collapse
Affiliation(s)
- Kalyan C Vinnakota
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.
| | - Jason N Bazil
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Françoise Van den Bergh
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Robert W Wiseman
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| |
Collapse
|
4
|
Tran K, Loiselle DS, Crampin EJ. Regulation of cardiac cellular bioenergetics: mechanisms and consequences. Physiol Rep 2015; 3:3/7/e12464. [PMID: 26229005 PMCID: PMC4552539 DOI: 10.14814/phy2.12464] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The regulation of cardiac cellular bioenergetics is critical for maintaining normal cell function, yet the nature of this regulation is not fully understood. Different mechanisms have been proposed to explain how mitochondrial ATP production is regulated to match changing cellular energy demand while metabolite concentrations are maintained. We have developed an integrated mathematical model of cardiac cellular bioenergetics, electrophysiology, and mechanics to test whether stimulation of the dehydrogenase flux by Ca2+ or Pi, or stimulation of complex III by Pi can increase the rate of mitochondrial ATP production above that determined by substrate availability (ADP and Pi). Using the model, we show that, under physiological conditions the rate of mitochondrial ATP production can match varying demand through substrate availability alone; that ATP production rate is not limited by the supply of reducing equivalents in the form of NADH, as a result of Ca2+ or Pi activation of the dehydrogenases; and that ATP production rate is sensitive to feedback activation of complex III by Pi. We then investigate the mechanistic implications on cytosolic ion homeostasis and force production by simulating the concentrations of cytosolic Ca2+, Na+ and K+, and activity of the key ATPases, SERCA pump, Na+/K+ pump and actin-myosin ATPase, in response to increasing cellular energy demand. We find that feedback regulation of mitochondrial complex III by Pi improves the coupling between energy demand and mitochondrial ATP production and stabilizes cytosolic ADP and Pi concentrations. This subsequently leads to stabilized cytosolic ionic concentrations and consequentially reduced energetic cost from cellular ATPases.
Collapse
Affiliation(s)
- Kenneth Tran
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Denis S Loiselle
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Edmund J Crampin
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Parkville, Victoria, Australia School of Mathematics and Statistics, University of Melbourne, Parkville, Victoria, Australia School of Medicine, University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
5
|
Camara AKS, Bienengraeber M, Stowe DF. Mitochondrial approaches to protect against cardiac ischemia and reperfusion injury. Front Physiol 2011; 2:13. [PMID: 21559063 PMCID: PMC3082167 DOI: 10.3389/fphys.2011.00013] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 03/24/2011] [Indexed: 12/18/2022] Open
Abstract
The mitochondrion is a vital component in cellular energy metabolism and intracellular signaling processes. Mitochondria are involved in a myriad of complex signaling cascades regulating cell death vs. survival. Importantly, mitochondrial dysfunction and the resulting oxidative and nitrosative stress are central in the pathogenesis of numerous human maladies including cardiovascular diseases, neurodegenerative diseases, diabetes, and retinal diseases, many of which are related. This review will examine the emerging understanding of the role of mitochondria in the etiology and progression of cardiovascular diseases and will explore potential therapeutic benefits of targeting the organelle in attenuating the disease process. Indeed, recent advances in mitochondrial biology have led to selective targeting of drugs designed to modulate or manipulate mitochondrial function, to the use of light therapy directed to the mitochondrial function, and to modification of the mitochondrial genome for potential therapeutic benefit. The approach to rationally treat mitochondrial dysfunction could lead to more effective interventions in cardiovascular diseases that to date have remained elusive. The central premise of this review is that if mitochondrial abnormalities contribute to the etiology of cardiovascular diseases (e.g., ischemic heart disease), alleviating the mitochondrial dysfunction will contribute to mitigating the severity or progression of the disease. To this end, this review will provide an overview of our current understanding of mitochondria function in cardiovascular diseases as well as the potential role for targeting mitochondria with potential drugs or other interventions that lead to protection against cell injury.
Collapse
Affiliation(s)
- Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin Milwaukee, WI, USA
| | | | | |
Collapse
|
6
|
Beard DA. Simulation of cellular biochemical system kinetics. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2010; 3:136-46. [PMID: 21171044 DOI: 10.1002/wsbm.116] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The goal of realistically and reliably simulating the biochemical processes underlying cellular function is achievable through a systematic approach that makes use of the broadest possible amount of in vitro and in vivo data, and is consistent with all applicable physical chemical theories. Progress will be facilitated by establishing: (1) a concrete self-consistent theoretical foundation for systems simulation; (2) extensive and accurate databases of thermodynamic properties of biochemical reactions; (3) parameterized and validated models of enzyme and transporter catalytic mechanisms that are consistent with physical chemical theoretical foundation; and (4) software tools for integrating all these concepts, data, and models into a cohesive representation of cellular biochemical systems. Ongoing initiatives are laying the groundwork for the broad-based community cooperation that will be necessary to pursue these elements of a strategic infrastructure for systems simulation on a large scale.
Collapse
Affiliation(s)
- Daniel A Beard
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA.
| |
Collapse
|
7
|
Kim HW, Lee D, Pohost GM. (31)P cardiovascular magnetic resonance spectroscopy: a unique approach to the assessment of the myocardium. Future Cardiol 2010; 5:523-7. [PMID: 19886777 DOI: 10.2217/fca.09.40] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
8
|
|
9
|
Experimentally observed phenomena on cardiac energetics in heart failure emerge from simulations of cardiac metabolism. Proc Natl Acad Sci U S A 2009; 106:7143-8. [PMID: 19357309 DOI: 10.1073/pnas.0812768106] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The failing heart is hypothesized to suffer from energy supply inadequate for supporting normal cardiac function. We analyzed data from a canine left ventricular hypertrophy model to determine how the energy state evolves because of changes in key metabolic pools. Our findings--confirmed by in vivo (31)P-magnetic resonance spectroscopy--indicate that the transition between the clinically observed early compensatory phase and heart failure and the critical point at which the transition occurs are emergent properties of cardiac energy metabolism. Specifically, analysis reveals a phenomenon in which low and moderate reductions in metabolite pools have no major negative impact on oxidative capacity, whereas reductions beyond a critical tipping point lead to a severely compromised energy state. The transition point corresponds to reductions in the total adenine nucleotide pool (TAN) of approximately 30%, corresponding to the reduction observed in humans in heart failure [Ingwall JS, Weiss RG (2004) Is the failing heart energy starved? On using chemical energy to support cardiac function. Circ Res 95(2):135-145]. At given values of TAN and the total exchangeable phosphate pool during hypertrophic remodeling, the creatine pool attains a value that is associated with optimal ATP hydrolysis potential. Thus, both increases and decreases to the creatine pool are predicted to result in diminished energetic state unless accompanied by appropriate simultaneous changes in the other pools.
Collapse
|
10
|
Roles of the creatine kinase system and myoglobin in maintaining energetic state in the working heart. BMC SYSTEMS BIOLOGY 2009; 3:22. [PMID: 19228404 PMCID: PMC2667476 DOI: 10.1186/1752-0509-3-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 02/19/2009] [Indexed: 11/10/2022]
Abstract
BACKGROUND The heart is capable of maintaining contractile function despite a transient decrease in blood flow and increase in cardiac ATP demand during systole. This study analyzes a previously developed model of cardiac energetics and oxygen transport to understand the roles of the creatine kinase system and myoglobin in maintaining the ATP hydrolysis potential during beat-to-beat transient changes in blood flow and ATP hydrolysis rate. RESULTS The theoretical investigation demonstrates that elimination of myoglobin only slightly increases the predicted range of oscillation of cardiac oxygenation level during beat-to-beat transients in blood flow and ATP utilization. In silico elimination of myoglobin has almost no impact on the cytoplasmic ATP hydrolysis potential (DeltaGATPase). In contrast, disabling the creatine kinase system results in considerable oscillations of cytoplasmic ADP and ATP levels and seriously deteriorates the stability of DeltaGATPase in the beating heart. CONCLUSION The CK system stabilizes DeltaGATPase by both buffering ATP and ADP concentrations and enhancing the feedback signal of inorganic phosphate in regulating mitochondrial oxidative phosphorylation.
Collapse
|
11
|
Wu F, Zhang EY, Zhang J, Bache RJ, Beard DA. Phosphate metabolite concentrations and ATP hydrolysis potential in normal and ischaemic hearts. J Physiol 2008; 586:4193-208. [PMID: 18617566 DOI: 10.1113/jphysiol.2008.154732] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
To understand how cardiac ATP and CrP remain stable with changes in work rate - a phenomenon that has eluded mechanistic explanation for decades - data from (31)phosphate-magnetic resonance spectroscopy ((31)P-MRS) are analysed to estimate cytoplasmic and mitochondrial phosphate metabolite concentrations in the normal state, during high cardiac workstates, during acute ischaemia and reactive hyperaemic recovery. Analysis is based on simulating distributed heterogeneous oxygen transport in the myocardium integrated with a detailed model of cardiac energy metabolism. The model predicts that baseline myocardial free inorganic phosphate (P(i)) concentration in the canine myocyte cytoplasm - a variable not accessible to direct non-invasive measurement - is approximately 0.29 mm and increases to 2.3 mm near maximal cardiac oxygen consumption. During acute ischaemia (from ligation of the left anterior descending artery) P(i) increases to approximately 3.1 mm and ATP consumption in the ischaemic tissue is reduced quickly to less than half its baseline value before the creatine phosphate (CrP) pool is 18% depleted. It is determined from these experiments that the maximal rate of oxygen consumption of the heart is an emergent property and is limited not simply by the maximal rate of ATP synthesis, but by the maximal rate at which ATP can be synthesized at a potential at which it can be utilized. The critical free energy of ATP hydrolysis for cardiac contraction that is consistent with these findings is approximately -63.5 kJ mol(-1). Based on theoretical findings, we hypothesize that inorganic phosphate is both the primary feedback signal for stimulating oxidative phosphorylation in vivo and also the most significant product of ATP hydrolysis in limiting the capacity of the heart to hydrolyse ATP in vivo. Due to the lack of precise quantification of P(i) in vivo, these hypotheses and associated model predictions remain to be carefully tested experimentally.
Collapse
Affiliation(s)
- Fan Wu
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wiscosin, Milwaukee, WI 53213, USA
| | | | | | | | | |
Collapse
|
12
|
Synergistic myoprotection of L-arginine and adenosine in a canine model of global myocardial ischaemic reperfusion injury. Chin Med J (Engl) 2007. [DOI: 10.1097/00029330-200711020-00007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
13
|
Antunes F, Boveris A, Cadenas E. On the biologic role of the reaction of NO with oxidized cytochrome c oxidase. Antioxid Redox Signal 2007; 9:1569-79. [PMID: 17665969 DOI: 10.1089/ars.2007.1677] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The inhibition of cytochrome c oxidase (CcOX) by nitric oxide (NO) is analyzed with a mathematical model that simulates the metabolism in vivo. The main results were the following: (a) We derived novel equations for the catalysis of CcOX that can be used to predict CcOX inhibition in any tissue for any [NO] or [O(2)]; (b) Competitive inhibition (resulting from the reversible binding of NO to reduced CcOX) emerges has the sole relevant component of CcOX inhibition under state 3 in vivo; (c) In state 4, contribution of uncompetitive inhibition (resulting from the reaction of oxidized CcOX with NO) represents a significant nonmajority fraction of inhibition, being favored by high [O(2)]; and (d) The main biologic role of the reaction between NO and oxidized CcOX is to consume NO. By reducing [NO], this reaction stimulates, rather than inhibits, respiration. Finally, we propose that the biologic role of NO as an inhibitor of CcOX is twofold: in state 4, it avoids an excessive buildup of mitochondrial membrane potential that triggers rapid production of oxidants, and in state 3, increases the efficiency of oxidative phosphorylation by increasing the ADP/O ratio, supporting the therapeutic use of NO in situations in which mitochondria are dysfunctional.
Collapse
Affiliation(s)
- Fernando Antunes
- Grupo de Bioquímica dos Oxidantes e Antioxidantes, Centro de Química e Bioquímica and Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, P-1250-047 Lisboa, Portugal.
| | | | | |
Collapse
|
14
|
Behnke BJ, Delp MD, Poole DC, Musch TI. Aging potentiates the effect of congestive heart failure on muscle microvascular oxygenation. J Appl Physiol (1985) 2007; 103:1757-63. [PMID: 17761789 DOI: 10.1152/japplphysiol.00487.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Congestive heart failure (CHF) is most prevalent in aged individuals and elicits a spectrum of cardiovascular and muscular perturbations that impairs the ability to deliver (Qo(2)) and utilize (Vo(2)) oxygen in skeletal muscle. Whether aging potentiates the CHF-induced alterations in the Qo(2)-to-Vo(2) relationship [which determines microvascular Po(2) (Pmv(O(2)))] in resting and contracting skeletal muscle is unclear. We tested the hypothesis that old rats with CHF would demonstrate a greater impairment of skeletal muscle Pmv(O(2)) than observed in young rats with CHF. Phosphorescence quenching was utilized to measure spinotrapezius Pmv(O(2)) at rest and across the rest-to-contractions (1-Hz, 4-6 V) transition in young (Y) and old (O) male Fischer 344 Brown-Norway rats with CHF induced by myocardial infarction (mean left ventricular end-diastolic pressure >20 mmHg for Y(CHF) and O(CHF)). In CHF muscle, aging significantly reduced resting Pmv(O(2)) (32.3 +/- 3.4 Torr for Y(CHF) and 21.3 +/- 3.3 Torr for O(CHF); P < 0.05) and in both Y(CHF) and O(CHF) compared with their aged-matched counterparts, CHF reduced the rate of the Pmv(O(2)) fall at the onset of contractions. Moreover, across the on-transient and in the subsequent steady state, Pmv(O(2)) values in O(CHF) vs. Y(CHF) were substantially lower (for steady-state, 20.4 +/- 1.7 Torr for Y(CHF) and 16.4 +/- 2.0 Torr for O(CHF); P < 0.05). At rest and during contractions in CHF, the pressure driving blood-muscle O(2) diffusion (Pmv(O(2))) is substantially decreased in old animals. This finding suggests that muscle dysfunction and exercise intolerance in aged CHF patients might be due, in part, to the failure to maintain a sufficiently high Pmv(O(2)) to facilitate blood-muscle O(2) exchange and support mitochondrial ATP production.
Collapse
Affiliation(s)
- Bradley J Behnke
- Division of Exercise Physiology, and the Center for Interdisciplinary Research in Cardiovascular Sciences, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | | | | | | |
Collapse
|
15
|
Kaluski E, Hendler A, Blatt A, Uriel N. Nitric oxide synthase inhibitors in post-myocardial infarction cardiogenic shock--an update. Clin Cardiol 2007; 29:482-8. [PMID: 17133844 PMCID: PMC6654158 DOI: 10.1002/clc.4960291103] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cardiogenic shock (CS) in acute myocardial infarction, after successful coronary angioplasty, still carries a case fatality rate of 50%. These patients succumb to a systemic metabolic storm, superimposed on extensive myocardial necrosis and stunning. Nitric oxide (NO) overproduction contributes to the pathophysiology of this morbid state. Current data regarding the physiologic effects of NO and nitric oxide synthase (NOS) inhibitors on the cardiovascular system are reviewed. Clinical trials assessing the safety and efficacy of NOS inhibitors in CS are summarized.
Collapse
Affiliation(s)
- Edo Kaluski
- Department of Cardiology, Assaf Harofeh Medical Center, Zrifin, Israel.
| | | | | | | |
Collapse
|
16
|
Lee J, Hu Q, Nakamura Y, Wang X, Zhang X, Zhu X, Chen W, Yang Q, Zhang J. Open-chest 31P magnetic resonance spectroscopy of mouse heart at 4.7 Tesla. J Magn Reson Imaging 2007; 24:1269-76. [PMID: 17096395 DOI: 10.1002/jmri.20766] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
PURPOSE To develop a rapid, robust, and accurate method for assessing myocardial energetics in mice and demonstrate its applicability to mouse models of acquired and genetic heart disease. MATERIALS AND METHODS We combined surface coil localization (10-mm diameter, tunable between (1)H and (31)P, using adiabatic half-passage radiofrequency pulses) and surgery (electrocautery removal of anterior chest wall) to create an open-chest method for acquiring in vivo (31)P nuclear magnetic resonance (NMR) cardiac spectra from mice at 4.7T within 12 minutes. Normal BALB/c mice, BALB/c with myocardial infarction (MI), cardiomyocyte-restricted peroxisome proliferator-activated receptor-delta knockout (KO) (CR-PPARd(-/-)) and control loxP-flanked Ppard (Ppard(flox/flox)) mice were examined. RESULTS The mean phosphocreatine (PCr)/adenosine triphosphate (ATP) ratios in control BALB/c mice, BALB/c MI mice, Ppard(flox/flox) mice, and PPAR-delta KO mice were 2.13 +/- 0.09 (N = 11), 1.35 +/- 0.07 (N = 9, P < 0.001 vs. BALB/c control), 1.92 +/- 0.09 (N = 5), and 1.31 +/- 0.12 (N = 5, P < 0.005 vs. Ppard(flox/flox) control), respectively. The significant depression of myocardial PCr/ATP we observed in these genetic/acquired models of heart disease was in accord with previous data from analogous large animal models. No NMR signal contamination from chamber blood or adjacent skeletal muscle was identified. CONCLUSION This new technique provides cardiac (31)P spectra suitable for accurate quantitative analysis in a relatively short acquisition time, is suitable for terminal studies of mouse myocardial energy metabolism, and could be installed in virtually any NMR laboratory to study myocardial energetics in numerous mouse models of human heart disease.
Collapse
Affiliation(s)
- Joseph Lee
- Department of Medicine, University of Minnesota Academic Health Center, Minneapolis, Minnesota 55455, USA
| | | | | | | | | | | | | | | | | |
Collapse
|