1
|
Widmaier M, Lim SI, Wenz D, Xin L. Fast in vivo assay of creatine kinase activity in the human brain by 31 P magnetic resonance fingerprinting. NMR IN BIOMEDICINE 2023; 36:e4998. [PMID: 37424110 DOI: 10.1002/nbm.4998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 05/15/2023] [Accepted: 06/12/2023] [Indexed: 07/11/2023]
Abstract
A new and efficient magnetisation transfer 31 P magnetic resonance fingerprinting (MT-31 P-MRF) approach is introduced to measure the creatine kinase metabolic ratek CK between phosphocreatine (PCr) and adenosine triphosphate (ATP) in human brain. The MRF framework is extended to overcome challenges in conventional 31 P measurement methods in the human brain, enabling reduced acquisition time and specific absorption rate (SAR). To address the challenge of creating and matching large multiparametric dictionaries in an MRF scheme, a nested iteration interpolation method (NIIM) is introduced. As the number of parameters to estimate increases, the size of the dictionary grows exponentially. NIIM can reduce the computational load by breaking dictionary matching into subsolutions of linear computational order. MT-31 P-MRF combined with NIIM providesT 1 PCr ,T 1 ATP andk CK estimates in good agreement with those obtained by the exchange kinetics by band inversion transfer (EBIT) method and literature values. Furthermore, the test-retest reproducibility results showed that MT-31 P-MRF achieves a similar or better coefficient of variation (<12%) forT 1 ATP andk CK measurements in 4 min 15 s, than EBIT with 17 min 4 s scan time, enabling a fourfold reduction in scan time. We conclude that MT-31 P-MRF in combination with NIIM is a fast, accurate, and reproducible approach for in vivok CK assays in the human brain, which enables the potential to investigate energy metabolism in a clinical setting.
Collapse
Affiliation(s)
- Mark Widmaier
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Laboratory for Functional and Metabolic Imaging, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Song-I Lim
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Laboratory for Functional and Metabolic Imaging, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Daniel Wenz
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Lijing Xin
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| |
Collapse
|
2
|
Gupta A. Cardiac 31P MR spectroscopy: development of the past five decades and future vision-will it be of diagnostic use in clinics? Heart Fail Rev 2023; 28:485-532. [PMID: 36427161 DOI: 10.1007/s10741-022-10287-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/16/2022] [Indexed: 11/27/2022]
Abstract
In the past five decades, the use of the magnetic resonance (MR) technique for cardiovascular diseases has engendered much attention and raised the opportunity that the technique could be useful for clinical applications. MR has two arrows in its quiver: One is magnetic resonance imaging (MRI), and the other is magnetic resonance spectroscopy (MRS). Non-invasively, highly advanced MRI provides unique and profound information about the anatomical changes of the heart. Excellently developed MRS provides irreplaceable and insightful evidence of the real-time biochemistry of cardiac metabolism of underpinning diseases. Compared to MRI, which has already been successfully applied in routine clinical practice, MRS still has a long way to travel to be incorporated into routine diagnostics. Considering the exceptional potential of 31P MRS to measure the real-time metabolic changes of energetic molecules qualitatively and quantitatively, how far its powerful technique should be waited before a successful transition from "bench-to-bedside" is enticing. The present review highlights the seminal studies on the chronological development of cardiac 31P MRS in the past five decades and the future vision and challenges to incorporating it for routine diagnostics of cardiovascular disease.
Collapse
Affiliation(s)
- Ashish Gupta
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow, 226014, India.
| |
Collapse
|
3
|
Samuel TJ, Lai S, Schär M, Wu KC, Steinberg AM, Wei AC, Anderson M, Tomaselli GF, Gerstenblith G, Bottomley PA, Weiss RG. Myocardial ATP depletion detected noninvasively predicts sudden cardiac death risk in heart failure patients. JCI Insight 2022; 7:157557. [PMID: 35579938 PMCID: PMC9309047 DOI: 10.1172/jci.insight.157557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/06/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Sudden cardiac death (SCD) remains a worldwide public health problem in need of better noninvasive predictive tools. Current guidelines for primary preventive SCD therapies, such as implantable cardioverter defibrillators (ICDs), are based on left ventricular ejection fraction (LVEF), but these guidelines are imprecise: fewer than 5% of ICDs deliver lifesaving therapy per year. Impaired cardiac metabolism and ATP depletion cause arrhythmias in experimental models, but to our knowledge a link between arrhythmias and cardiac energetic abnormalities in people has not been explored, nor has the potential for metabolically predicting clinical SCD risk. METHODS We prospectively measured myocardial energy metabolism noninvasively with phosphorus magnetic resonance spectroscopy in patients with no history of significant arrhythmias prior to scheduled ICD implantation for primary prevention in the setting of reduced LVEF (≤35%). RESULTS By 2 different analyses, low myocardial ATP significantly predicted the composite of subsequent appropriate ICD firings for life-threatening arrhythmias and cardiac death over approximately 10 years. Life-threatening arrhythmia risk was approximately 3-fold higher in patients with low ATP and independent of established risk factors, including LVEF. In patients with normal ATP, rates of appropriate ICD firings were several-fold lower than reported rates of ICD complications and inappropriate firings. CONCLUSION To the best of our knowledge, these are the first data linking in vivo myocardial ATP depletion and subsequent significant arrhythmic events in people, suggesting an energetic component to clinical life-threatening ventricular arrhythmogenesis. The findings support investigation of metabolic strategies that limit ATP loss to treat or prevent life-threatening cardiac arrhythmias and herald noninvasive metabolic imaging as a complementary SCD risk stratification tool. TRIAL REGISTRATION ClinicalTrials.gov NCT00181233. FUNDING This work was supported by the DW Reynolds Foundation, the NIH (grants HL61912, HL056882, HL103812, HL132181, HL140034), and Russell H. Morgan and Clarence Doodeman endowments at Johns Hopkins.
Collapse
Affiliation(s)
- T Jake Samuel
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States of America
| | - Shenghan Lai
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, United States of America
| | - Michael Schär
- Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, United States of America
| | - Katherine C Wu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States of America
| | - Angela M Steinberg
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States of America
| | - An-Chi Wei
- Department of Electrical Engineering, National Taiwan University, Tapei, Taiwan
| | - Mark Anderson
- Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, United States of America
| | - Gordon F Tomaselli
- Division of Cardiology, Department of Medicine, The Albert Einstein College of Medicine, Bronx, United States of America
| | - Gary Gerstenblith
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States of America
| | - Paul A Bottomley
- Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, United States of America
| | - Robert G Weiss
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States of America
| |
Collapse
|
4
|
Keceli G, Gupta A, Sourdon J, Gabr R, Schär M, Dey S, Tocchetti CG, Stuber A, Agrimi J, Zhang Y, Leppo M, Steenbergen C, Lai S, Yanek LR, O’Rourke B, Gerstenblith G, Bottomley PA, Wang Y, Paolocci N, Weiss RG. Mitochondrial Creatine Kinase Attenuates Pathologic Remodeling in Heart Failure. Circ Res 2022; 130:741-759. [PMID: 35109669 PMCID: PMC8897235 DOI: 10.1161/circresaha.121.319648] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Abnormalities in cardiac energy metabolism occur in heart failure (HF) and contribute to contractile dysfunction, but their role, if any, in HF-related pathologic remodeling is much less established. CK (creatine kinase), the primary muscle energy reserve reaction which rapidly provides ATP at the myofibrils and regenerates mitochondrial ADP, is down-regulated in experimental and human HF. We tested the hypotheses that pathologic remodeling in human HF is related to impaired cardiac CK energy metabolism and that rescuing CK attenuates maladaptive hypertrophy in experimental HF. METHODS First, in 27 HF patients and 14 healthy subjects, we measured cardiac energetics and left ventricular remodeling using noninvasive magnetic resonance 31P spectroscopy and magnetic resonance imaging, respectively. Second, we tested the impact of metabolic rescue with cardiac-specific overexpression of either Ckmyofib (myofibrillar CK) or Ckmito (mitochondrial CK) on HF-related maladaptive hypertrophy in mice. RESULTS In people, pathologic left ventricular hypertrophy and dilatation correlate closely with reduced myocardial ATP levels and rates of ATP synthesis through CK. In mice, transverse aortic constriction-induced left ventricular hypertrophy and dilatation are attenuated by overexpression of CKmito, but not by overexpression of CKmyofib. CKmito overexpression also attenuates hypertrophy after chronic isoproterenol stimulation. CKmito lowers mitochondrial reactive oxygen species, tissue reactive oxygen species levels, and upregulates antioxidants and their promoters. When the CK capacity of CKmito-overexpressing mice is limited by creatine substrate depletion, the protection against pathologic remodeling is lost, suggesting the ADP regenerating capacity of the CKmito reaction rather than CK protein per se is critical in limiting adverse HF remodeling. CONCLUSIONS In the failing human heart, pathologic hypertrophy and adverse remodeling are closely related to deficits in ATP levels and in the CK energy reserve reaction. CKmito, sitting at the intersection of cardiac energetics and redox balance, plays a crucial role in attenuating pathologic remodeling in HF. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00181259.
Collapse
Affiliation(s)
- Gizem Keceli
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Ashish Gupta
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Joevin Sourdon
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Refaat Gabr
- Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, US
| | - Michael Schär
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Swati Dey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, US
| | - Carlo G. Tocchetti
- Department of Translational Medical Sciences, Interdepartmental Center for Clinical and Translational Research (CIRCET), Interdepartmental Hypertension Research Center (CIRIAPA), Federico II University, Naples, Italy
| | - Annina Stuber
- École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jacopo Agrimi
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Yi Zhang
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Michelle Leppo
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD US
| | - Shenghan Lai
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, US
| | - Lisa R. Yanek
- Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Brian O’Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Gary Gerstenblith
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Paul A. Bottomley
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| | - Yibin Wang
- Departments of Anesthesiology and Medicine, University of California at Los Angeles, Los Angeles, CA, US
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Robert G. Weiss
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, US
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, US
| |
Collapse
|
5
|
Ren J, Sherry AD, Malloy CR. Modular 31 P wideband inversion transfer for integrative analysis of adenosine triphosphate metabolism, T 1 relaxation and molecular dynamics in skeletal muscle at 7T. Magn Reson Med 2019; 81:3440-3452. [PMID: 30793793 DOI: 10.1002/mrm.27686] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/16/2019] [Accepted: 01/18/2019] [Indexed: 12/13/2022]
Abstract
PURPOSE For efficient and integrative analysis of de novo adenosine triphosphate (ATP) synthesis, creatine-kinase-mediated ATP synthesis, T1 relaxation time, and ATP molecular motion dynamics in human skeletal muscle at rest. METHODS Four inversion-transfer modules differing in center inversion frequency were combined to generate amplified magnetization transfer (MT) effects in targeted MT pathways, including Pi ↔ γ-ATP, PCr ↔ γ-ATP, and 31 Pγ(α)ATP ↔ 31 PβATP . MT effects from both forward and reverse exchange kinetic pathways were acquired to reduce potential bias and confounding factors in integrated data analysis. RESULTS Kinetic data collected using 4 wideband inversion modules (8 minutes each) yielded the forward exchange rate constants, kPCr →γ ATP = 0.31 ± 0.05 s-1 and kPi →γ ATP = 0.064 ± 0.012 s-1 , and the reverse exchange rate constants, kγATP→Pi = 0.034 ± 0.006 s-1 and kγATP→PCr = 1.37 ± 0.22 s-1 , respectively. The cross-relaxation rate constant, σγ(α) ↔ βATP was -0.20 ± 0.03 s-1 , corresponding to ATP rotational correlation time τc of 0.8 ± 0.1 × 10-7 seconds. The intrinsic T1 relaxation times were Pi (9.2 ± 1.4 seconds), PCr (6.2 ± 0.4 seconds), γ-ATP (1.8 ± 0.1 seconds), α-ATP (1.4 ± 0.1 seconds), and β-ATP (1.1 ± 0.1 seconds). Muscle ATP T1 values were found to be significantly longer than those previously measured in the brain using a similar method. CONCLUSION A combination of multiple inversion transfer modules provides a comprehensive and integrated analysis of ATP metabolism and molecular motion dynamics. This relatively fast technique could be potentially useful for studying metabolic disorders in skeletal muscle.
Collapse
Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Chemistry, University of Texas at Dallas, Richardson, Texas
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,VA North Texas Health Care System, Dallas, Texas
| |
Collapse
|
6
|
Gabr RE, El-Sharkawy AMM, Schär M, Panjrath GS, Gerstenblith G, Weiss RG, Bottomley PA. Cardiac work is related to creatine kinase energy supply in human heart failure: a cardiovascular magnetic resonance spectroscopy study. J Cardiovasc Magn Reson 2018; 20:81. [PMID: 30526611 PMCID: PMC6287363 DOI: 10.1186/s12968-018-0491-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 09/12/2018] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND It has been hypothesized that the supply of chemical energy may be insufficient to fuel normal mechanical pump function in heart failure (HF). The creatine kinase (CK) reaction serves as the heart's primary energy reserve, and the supply of adenosine triphosphate (ATP flux) it provides is reduced in human HF. However, the relationship between the CK energy supply and the mechanical energy expended has never been quantified in the human heart. This study tests whether reduced CK energy supply is associated with reduced mechanical work in HF patients. METHODS Cardiac mechanical work and CK flux in W/kg, and mechanical efficiency were measured noninvasively at rest using cardiac pressure-volume loops, magnetic resonance imaging and phosphorus spectroscopy in 14 healthy subjects and 27 patients with mild-to-moderate HF. RESULTS In HF, the resting CK flux (126 ± 46 vs. 179 ± 50 W/kg, p < 0.002), the average (6.8 ± 3.1 vs. 10.1 ± 1.5 W/kg, p <0.001) and the peak (32 ± 14 vs. 48 ± 8 W/kg, p < 0.001) cardiac mechanical work-rates, as well as the cardiac mechanical efficiency (53% ± 16 vs. 79% ± 3, p < 0.001), were all reduced by a third compared to healthy subjects. In addition, cardiac CK flux correlated with the resting peak and average mechanical power (p < 0.01), and with mechanical efficiency (p = 0.002). CONCLUSION These first noninvasive findings showing that cardiac mechanical work and efficiency in mild-to-moderate human HF decrease proportionately with CK ATP energy supply, are consistent with the energy deprivation hypothesis of HF. CK energy supply exceeds mechanical work at rest but lies within a range that may be limiting with moderate activity, and thus presents a promising target for HF treatment. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT00181259 .
Collapse
Affiliation(s)
- Refaat E. Gabr
- Division of MR Research, Department of Radiology, The Johns Hopkins University, Park Building, 600 N Wolfe St, Baltimore, MD 21287 USA
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, Texas USA
| | - AbdEl-Monem M. El-Sharkawy
- Division of MR Research, Department of Radiology, The Johns Hopkins University, Park Building, 600 N Wolfe St, Baltimore, MD 21287 USA
- Systems and Biomedical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt
| | - Michael Schär
- Division of MR Research, Department of Radiology, The Johns Hopkins University, Park Building, 600 N Wolfe St, Baltimore, MD 21287 USA
| | - Gurusher S. Panjrath
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD USA
- The GW Heart and Vascular Institute, George Washington University School of Medicine and Health Sciences, Washington DC, USA
| | - Gary Gerstenblith
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD USA
| | - Robert G. Weiss
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD USA
| | - Paul A. Bottomley
- Division of MR Research, Department of Radiology, The Johns Hopkins University, Park Building, 600 N Wolfe St, Baltimore, MD 21287 USA
| |
Collapse
|
7
|
Shishmarev D, Kuchel PW. NMR magnetization-transfer analysis of rapid membrane transport in human erythrocytes. Biophys Rev 2016; 8:369-384. [PMID: 28510013 PMCID: PMC5425803 DOI: 10.1007/s12551-016-0221-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 09/13/2016] [Indexed: 10/20/2022] Open
Abstract
Nuclear magnetic resonance (NMR) magnetization-transfer (MT) experiments provide a convenient tool for studying rapid sub-second membrane-transport processes in situ in metabolically active cells. These experiments are used with membrane-permeable substances when separate (resolved) NMR signals are observed from their populations inside and outside the cells. Here, we provide a description of the theory and practice of the most common NMR MT experiments that have been used to study membrane-transport processes in human erythrocytes (red blood cells; RBCs). The procedures, involved in the analysis of the experimental data for defining mechanisms of transport, and for estimating values of kinetic parameters in the corresponding mathematical models, are given special attention.
Collapse
Affiliation(s)
- Dmitry Shishmarev
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Philip W Kuchel
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia.
| |
Collapse
|
8
|
Ren J, Sherry AD, Malloy CR. Efficient 31 P band inversion transfer approach for measuring creatine kinase activity, ATP synthesis, and molecular dynamics in the human brain at 7 T. Magn Reson Med 2016; 78:1657-1666. [PMID: 27868234 DOI: 10.1002/mrm.26560] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 10/16/2016] [Accepted: 11/03/2016] [Indexed: 01/28/2023]
Abstract
PURPOSE To develop an efficient 31 P magnetic resonance spectroscopy (MRS) method for measuring creatine kinase (CK) activity, adenosine triphosphate (ATP) synthesis, and motion dynamics in the human brain at 7 Tesla (T). METHODS Three band inversion modules differing in center frequency were used to induce magnetization transfer (MT) effect in three exchange pathways: (i) CK-mediated reaction PCr → γ-ATP; (ii) de novo ATP synthesis Pi → γ-ATP; and (iii) ATP intramolecular 31 P-31 P cross-relaxation γ-(α-) ↔ β-ATP. The resultant MT data were analyzed using a 5-pool model in the format of magnetization matrix according to Bloch-McConnell-Solomon formalism. RESULTS With a repetition time (TR) of 4 s, the scan time for each module was approximately 8 min. The rate constants were kPCr → γATP 0.38 ± 0.02 s-1 , kPi → γATP 0.19 ± 0.02 s-1 , and σγ(α) ↔ βATP 0.19 ± 0.04 s-1 , corresponding to ATP rotation correlation time τc (0.8 ± 0.2) ·10-7 s. The T1 relaxation times were Pi 7.26 ± 1.76 s, PCr 5.99 ± 0.58 s, γ-ATP 0.98 ± 0.07 s, α-ATP 0.95 ± 0.04 s, and β-ATP 0.68 ± 0.03 s. CONCLUSION Short-TR band inversion modules provide a time-efficient way of measuring brain ATP metabolism and could be useful in studying metabolic disorders in brain diseases. Magn Reson Med 78:1657-1666, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Chemistry, University of Texas at Dallas, Richardson, Texas, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,VA North Texas Health Care System, Dallas, Texas, USA
| |
Collapse
|
9
|
Pouymayou B, Buehler T, Kreis R, Boesch C. Test-retest analysis of multiple 31 P magnetization exchange pathways using asymmetric adiabatic inversion. Magn Reson Med 2016; 78:33-39. [PMID: 27455454 DOI: 10.1002/mrm.26337] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/31/2016] [Accepted: 06/17/2016] [Indexed: 01/08/2023]
Abstract
PURPOSE A 31 P-MR inversion transfer (IT) method with a short adiabatic inversion pulse is proposed and its test-retest reliability was evaluated for two spectral fitting strategies. METHODS Assessment in a test-retest design (3 Tesla, vastus muscles, 12 healthy volunteers, 14 inversion times, 22 ms asymmetric adiabatic inversion pulse, adiabatic excitation); spectral fitting in Fitting Tool for Interrelated Arrays of Datasets (FitAID) and Java Magnetic Resonance User Interface (jMRUI); least squares solution of the Bloch-McConnell-Solomon matrix formalism including all 14 measured time-points with equal weighting. RESULTS The cohort averages of k[PCr→γ-ATP] (phosphocreatine, PCr; adenosine triphosphate, ATP) are 0.246 ± 0.050s-1 versus 0.254 ± 0.050s-1 , and k[Pi→γ-ATP] 0.086 ± 0.033s-1 versus 0.066 ± 0.034s-1 (average ± standard deviation, jMRUI versus FitAID). Coefficients of variation of the differences between test and retest are lowest (9.5%) for k[PCr→γ-ATP] fitted in FitAID, larger (15.2%) for the fit in jMRUI, and considerably larger for k[Pi→γ-ATP] fitted in FitAID (43.4%) or jMRUI (47.9%). The beginning of the IT effect can be observed with magnetizations above 92% for noninverted lines while inversion of the ATP resonances is better than -72%. CONCLUSION The performance of the asymmetric adiabatic pulse allows an accurate observation of IT effects even in the early phase; the least squares fit of the Bloch-McConnell-Solomon matrix formalism is robust; and the type of spectral fitting can influence the results significantly. Magn Reson Med 78:33-39, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Bertrand Pouymayou
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Tania Buehler
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| | - Roland Kreis
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| | - Chris Boesch
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| |
Collapse
|
10
|
Cui MH, Jayalakshmi K, Liu L, Guha C, Branch CA. In vivo (1)H MRS and (31)P MRSI of the response to cyclocreatine in transgenic mouse liver expressing creatine kinase. NMR IN BIOMEDICINE 2015; 28:1634-1644. [PMID: 26451872 DOI: 10.1002/nbm.3391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 08/05/2015] [Accepted: 08/11/2015] [Indexed: 06/05/2023]
Abstract
Hepatocyte transplantation has been explored as a therapeutic alternative to liver transplantation, but a means to monitor the success of the procedure is lacking. Published findings support the use of in vivo (31)P MRSI of creatine kinase (CK)-expressing hepatocytes to monitor proliferation of implanted hepatocytes. Phosphocreatine tissue level depends upon creatine (Cr) input to the CK enzyme reaction, but Cr measurement by (1)H MRS suffers from low signal-to-noise ratio (SNR). We examine the possibility of using the Cr analog cyclocreatine (CCr, a substrate for CK), which is quickly phosphorylated to phosphocyclocreatine (PCCr), as a higher SNR alternative to Cr. (1)H MRS and (31)P MRSI were employed to measure the effect of incremental supplementation of CCr upon PCCr, γ-ATP, pH and Pi /ATP in the liver of transgenic mice expressing the BB isoform of CK (CKBB) in hepatocytes. Water supplementation with 0.1% CCr led to a peak total PCCr level of 17.15 ± 1.07 mmol/kg wet weight by 6 weeks, while adding 1.0% CCr led to a stable PCCr liver level of 18.12 ± 3.91 mmol/kg by the fourth day of feeding. PCCr was positively correlated with CCr, and ATP concentration and pH declined with increasing PCCr. Feeding with 1% CCr in water induced an apparent saturated level of PCCr, suggesting that CCr quantization may not be necessary for quantifying expression of CK in mice. These findings support the possibility of using (31)P MRS to noninvasively monitor hepatocyte transplant success with CK-expressing hepatocytes.
Collapse
Affiliation(s)
- Min-Hui Cui
- Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Kamaiah Jayalakshmi
- Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Laibin Liu
- Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Chandan Guha
- Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Craig A Branch
- Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, USA
| |
Collapse
|
11
|
Schär M, Gabr RE, El-Sharkawy AMM, Steinberg A, Bottomley PA, Weiss RG. Two repetition time saturation transfer (TwiST) with spill-over correction to measure creatine kinase reaction rates in human hearts. J Cardiovasc Magn Reson 2015; 17:70. [PMID: 26253320 PMCID: PMC4529717 DOI: 10.1186/s12968-015-0175-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/21/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phosphorus saturation transfer (ST) magnetic resonance spectroscopy can measure the rate of ATP generated from phosphocreatine (PCr) via creatine kinase (CK) in the human heart. Recently, the triple-repetition time ST (TRiST) method was introduced to measure the CK pseudo-first-order rate constant kf in three acquisitions. In TRiST, the longitudinal relaxation time of PCr while γ-ATP is saturated, T1`, is measured for each subject, but suffers from low SNR because the PCr signal is reduced due to exchange with saturated γ-ATP, and the short repetition time of one of the acquisitions. Here, a two-repetition time ST (TwiST) method is presented. In TwiST, the acquisition with γ-ATP saturation and short repetition time is dropped. Instead of measuring T1`, an intrinsic relaxation time T1 for PCr, T1 (intrinsic), is assumed. The objective was to validate TwiST measurements of CK kinetics in healthy subjects and patients with heart failure (HF). METHODS Bloch equation simulations that included the effect of spillover irradiation on PCr were used to derive formulae for T1 (intrinsic) and kf measured by both TRiST and TwiST methods. Spillover was quantified from an unsaturated PCr measurement used in the current protocol for determining PCr and ATP concentrations. Cardiac TRiST and TwiST data were acquired at 3 T from 12 healthy and 17 HF patients. RESULTS Simulations showed that both kf measured by TwiST and T1 (intrinsic) require spill-over corrections. In human heart at 3 T, the spill-over corrected T1 (intrinsic) = 8.4 ± 1.4 s (mean ± SD) independent of study group. TwiST and TRiST kf measurements were the same, but TwiST was 9 min faster. Spill-over corrected TwiST kf was 0.33 ± 0.08 s(-1) vs. 0.20 ± 0.06 s(-1) in healthy vs HF hearts, respectively (p < 0.0001). CONCLUSION TwiST was validated against TRiST in the human heart at 3 T, generating the same results 9 min faster. TwiST detected significant reductions in CK kf in HF compared to healthy subjects, consistent with prior 1.5 T studies using different methodology.
Collapse
Affiliation(s)
- Michael Schär
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Refaat E Gabr
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, USA.
| | - AbdEl-Monem M El-Sharkawy
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Systems and Biomedical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt.
| | - Angela Steinberg
- Cardiology Division, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Paul A Bottomley
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Robert G Weiss
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cardiology Division, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
12
|
Three-dimensional saturation transfer ³¹P-MRI in muscles of the lower leg at 3.0 T. Sci Rep 2014; 4:5219. [PMID: 24910264 PMCID: PMC4048915 DOI: 10.1038/srep05219] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 05/19/2014] [Indexed: 02/02/2023] Open
Abstract
The creatine kinase (CK) reaction plays a critical role in skeletal muscle function, and can be studied non-invasively using phosphorus (31P) saturation transfer (ST) techniques. However, due to the low MR sensitivity of the 31P nucleus, most studies on clinically approved magnetic fields (≤3.0 T) have been performed with coarse resolution and limited tissue coverage. However, such methods are not able to detect spatially resolved metabolic heterogeneities, which may be important in diseases of the skeletal muscle. In this study, our aim was to develop and implement a 31P-MRI method for mapping the kinetics of the CK reaction, and the unidirectional phosphocreatine (PCr) to adenosine triphosphate (ATP) metabolic fluxes in muscles of the lower leg on a clinical 3.0 T MR scanner. We imaged the lower leg muscles of ten healthy volunteers (total experimental time: 40 min, nominal voxel sizes 0.5 mL), and found statistically significant differences between the kinetics of the CK reaction among muscle groups. Our developed technique may allow in the future the early detection of focal metabolic abnormalities in diseases that affect the function of the skeletal muscle.
Collapse
|
13
|
Bottomley PA, Panjrath GS, Lai S, Hirsch GA, Wu K, Najjar SS, Steinberg A, Gerstenblith G, Weiss RG. Metabolic rates of ATP transfer through creatine kinase (CK Flux) predict clinical heart failure events and death. Sci Transl Med 2013; 5:215re3. [PMID: 24337482 PMCID: PMC4440545 DOI: 10.1126/scitranslmed.3007328] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Morbidity and mortality from heart failure (HF) are high, and current risk stratification approaches for predicting HF progression are imperfect. Adenosine triphosphate (ATP) is required for normal cardiac contraction, and abnormalities in creatine kinase (CK) energy metabolism, the primary myocardial energy reserve reaction, have been observed in experimental and clinical HF. However, the prognostic value of abnormalities in ATP production rates through CK in human HF has not been investigated. Fifty-eight HF patients with nonischemic cardiomyopathy underwent ³¹P magnetic resonance spectroscopy (MRS) to quantify cardiac high-energy phosphates and the rate of ATP synthesis through CK (CK flux) and were prospectively followed for a median of 4.7 years. Multiple-event analysis (MEA) was performed for HF-related events including all-cause and cardiac death, HF hospitalization, cardiac transplantation, and ventricular-assist device placement. Among baseline demographic, clinical, and metabolic parameters, MEA identified four independent predictors of HF events: New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF), African-American race, and CK flux. Reduced myocardial CK flux was a significant predictor of HF outcomes, even after correction for NYHA class, LVEF, and race. For each increase in CK flux of 1 μmol g⁻¹ s⁻¹, risk of HF-related composite outcomes decreased by 32 to 39%. These findings suggest that reduced CK flux may be a potential HF treatment target. Newer imaging strategies, including noninvasive ³¹P MRS that detect altered ATP kinetics, could thus complement risk stratification in HF and add value in conditions involving other tissues with high energy demands, including skeletal muscle and brain.
Collapse
Affiliation(s)
- Paul A. Bottomley
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Gurusher S. Panjrath
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Shenghan Lai
- Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Glenn A. Hirsch
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Katherine Wu
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Samer S. Najjar
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- MedStar Health Research Institute, MedStar Washington Hospital Center, Washington, DC 20010, USA
| | - Angela Steinberg
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Gary Gerstenblith
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Robert G. Weiss
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| |
Collapse
|
14
|
Abraham MR, Bottomley PA, Dimaano VL, Pinheiro A, Steinberg A, Traill TA, Abraham TP, Weiss RG. Creatine kinase adenosine triphosphate and phosphocreatine energy supply in a single kindred of patients with hypertrophic cardiomyopathy. Am J Cardiol 2013; 112:861-6. [PMID: 23751935 DOI: 10.1016/j.amjcard.2013.05.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/02/2013] [Accepted: 05/02/2013] [Indexed: 01/20/2023]
Abstract
A lethal and extensively characterized familial form of hypertrophic cardiomyopathy (HC) is due to a point mutation (Arg403Gln) in the cardiac β-myosin heavy chain gene. Although this is associated with abnormal energy metabolism and progression to heart failure in an animal model, in vivo cardiac energetics have not been characterized in patients with this mutation. Noninvasive phosphorus saturation transfer magnetic resonance spectroscopy was used to measure the adenosine triphosphate supplied by the creatine kinase (CK) reaction and phosphocreatine, the heart's primary energy reserve, in 9 of 10 patients from a single kindred with HC caused by the Arg403GIn mutation and 17 age-matched healthy controls. Systolic and diastolic function was assessed by echocardiography in all 10 patients with HC. The patients with HC had impairment of diastolic function and mild systolic dysfunction, when assessed using global systolic longitudinal strain. Myocardial phosphocreatine was significantly decreased by 24% in patients (7.1 ± 2.3 μmol/g) compared with the controls (9.4 ± 1.2 μmol/g; p = 0.003). The pseudo-first-order CK rate-constant was 26% lower (0.28 ± 0.15 vs 0.38 ± 0.07 s⁻¹, p = 0.035) and the forward CK flux was 44% lower (2.0 ± 1.4 vs 3.6 ± 0.9 μmol/g/s, p = 0.001) than in the controls. The contractile abnormalities did not correlate with the metabolic indexes. In conclusion, myocardial phosphocreatine and CK-ATP delivery are significantly reduced in patients with HC caused by the Arg403Gln mutation, akin to previous results from mice with the same mutation. A lack of a relation between energetic and contractile abnormalities suggests the former result from the sarcomeric mutation and not a late consequence of mechanical dysfunction.
Collapse
|
15
|
Hirsch GA, Bottomley PA, Gerstenblith G, Weiss RG. Allopurinol acutely increases adenosine triphospate energy delivery in failing human hearts. J Am Coll Cardiol 2012; 59:802-8. [PMID: 22361399 DOI: 10.1016/j.jacc.2011.10.895] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 10/03/2011] [Accepted: 10/19/2011] [Indexed: 01/28/2023]
Abstract
OBJECTIVES This study tested the hypothesis that acute administration of the xanthine oxidase (XO) inhibitor allopurinol improves cardiac high-energy phosphate concentrations in human heart failure (HF) and increases the rate of adenosine triphosphate (ATP) synthesis through creatine kinase (CK), the primary myocardial energy reserve. BACKGROUND Studies of patients and animal models implicate impaired myocardial high-energy phosphate availability in HF. The XO reaction is a critical terminal step in ATP and purine degradation and an important source of reactive oxygen species. Thus, XO inhibition is a potentially attractive means to improve energy metabolism in the failing human heart. METHODS We randomized 16 patients with nonischemic cardiomyopathy in a double-blind fashion to allopurinol (300 mg intravenously) or placebo infusion, 4-to-1, the latter for purposes of blinding only. The myocardial concentrations of ATP and creatine phosphate (PCr) and the rate of ATP synthesis through CK (CK flux) were determined by (31)P magnetic resonance spectroscopy. RESULTS Allopurinol infusion increased mean cardiac PCr/ATP and PCr concentration by ∼11% (p < 0.02), and mean CK flux by 39% (2.07 ± 1.27 μmol/g/s to 2.87 ± 1.82 μmol/g/s, p < 0.007). Calculated cytosolic adenosine diphosphate concentration decreased, whereas the free energy of ATP hydrolysis (ΔG(∼ATP)) increased with allopurinol. The increased CK flux was disproportionate to substrate changes, indicating increased CK enzyme activity. CONCLUSIONS Intravenous administration of the XO inhibitor allopurinol acutely improves the relative and absolute concentrations of myocardial high-energy phosphates and ATP flux through CK in the failing human heart, offering direct evidence that myofibrillar CK energy delivery can be pharmaceutically augmented in the failing human heart. (Intravenous Allopurinol in Heart Failure; NCT00181155).
Collapse
Affiliation(s)
- Glenn A Hirsch
- Department of Medicine, Division of Cardiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | | | | |
Collapse
|
16
|
Schär M, El-Sharkawy AMM, Weiss RG, Bottomley PA. Triple repetition time saturation transfer (TRiST) 31P spectroscopy for measuring human creatine kinase reaction kinetics. Magn Reson Med 2010; 63:1493-501. [PMID: 20512852 DOI: 10.1002/mrm.22347] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Human cardiac phosphorus MR saturation transfer experiments to quantify creatine kinase forward rate constants (k(f)) have previously been performed at 1.5 T. Such experiments could benefit from increased signal-to-noise ratio (SNR) and spectral resolution at 3 T. At 1.5 T, the four-angle saturation transfer method was applied with low-angle adiabatic pulses and surface coils. However, low-angle adiabatic pulses are potentially problematic above 1.5 T due to bandwidth limitations, power requirements, power deposition, and intrapulse spin-spin relaxation. For localized metabolite spin-lattice relaxation time (T(1)) measurements, a dual repetition time approach with adiabatic half-passage pulses was recently introduced to solve these problems at 3 T. Because the saturation transfer experiment requires a T(1) measurement performed while one reacting moiety is saturated, we adapt the dual repetition time approach to measure k(f) using a triple repetition time saturation transfer (TRiST) method. A new pulsed saturation scheme with reduced sensitivity to static magnetic field inhomogeneity and compatibility with cardiac triggering is also presented. TRiST measurements of k(f) are validated in human calf muscle against conventional saturation transfer and found to agree within 3%. The first 3-T TRiST measurements of creatine kinase k(f) in the human calf (n = 6), chest muscle, and heart (n = 8) are 0.26 +/- 0.04 s(-1), 0.23 +/- 0.03 s(-1), and 0.32 +/- 0.07 s(-1), respectively, consistent with prior 1.5 T values.
Collapse
Affiliation(s)
- Michael Schär
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
| | | | | | | |
Collapse
|
17
|
Bottomley PA, Wu KC, Gerstenblith G, Schulman SP, Steinberg A, Weiss RG. Reduced myocardial creatine kinase flux in human myocardial infarction: an in vivo phosphorus magnetic resonance spectroscopy study. Circulation 2009; 119:1918-24. [PMID: 19332463 DOI: 10.1161/circulationaha.108.823187] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Energy metabolism is essential for myocellular viability. The high-energy phosphates adenosine triphosphate (ATP) and phosphocreatine (PCr) are reduced in human myocardial infarction (MI), reflecting myocyte loss and/or decreased intracellular ATP generation by creatine kinase (CK), the prime energy reserve of the heart. The pseudo-first-order CK rate constant, k, measures intracellular CK reaction kinetics and is independent of myocyte number within sampled tissue. CK flux is defined as the product of [PCr] and k. CK flux and k have never been measured in human MI. METHODS AND RESULTS Myocardial CK metabolite concentrations, k, and CK flux were measured noninvasively in 15 patients 7 weeks to 16 years after anterior MI using phosphorus magnetic resonance spectroscopy. In patients, mean myocardial [ATP] and [PCr] were 39% to 44% lower than in 15 control subjects (PCr=5.4+/-1.2 versus 9.6+/-1.1 micromol/g wet weight in MI versus control subjects, respectively, P<0.001; ATP=3.4+/-1.1 versus 5.5+/-1.3 micromol/g wet weight, P<0.001). The myocardial CK rate constant, k, was normal in MI subjects (0.31+/-0.08 s(-1)) compared with control subjects (0.33+/-0.07 s(-1)), as was PCr/ATP (1.74+/-0.27 in MI versus 1.87+/-0.45). However, CK flux was halved in MI [to 1.7+/-0.5 versus 3.3+/-0.8 micromol(g . s)(-1); P<0.001]. CONCLUSIONS These first observations of CK kinetics in prior human MI demonstrate that CK ATP supply is significantly reduced as a result of substrate depletion, likely attributable to myocyte loss. That k and PCr/ATP are unchanged in MI is consistent with the preservation of intracellular CK metabolism in surviving myocytes. Importantly, the results support therapies that primarily ameliorate the effects of tissue and substrate loss after MI and those that reduce energy demand rather than those that increase energy transfer or workload in surviving tissue.
Collapse
Affiliation(s)
- Paul A Bottomley
- Division of MR Research, Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
| | | | | | | | | | | |
Collapse
|