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Sowiński MP, Gahlawat S, Lund BA, Warnke AL, Hopmann KH, Lovett JE, Haugland MM. Conformational tuning improves the stability of spirocyclic nitroxides with long paramagnetic relaxation times. Commun Chem 2023; 6:111. [PMID: 37277501 DOI: 10.1038/s42004-023-00912-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/24/2023] [Indexed: 06/07/2023] Open
Abstract
Nitroxides are widely used as probes and polarization transfer agents in spectroscopy and imaging. These applications require high stability towards reducing biological environments, as well as beneficial relaxation properties. While the latter is provided by spirocyclic groups on the nitroxide scaffold, such systems are not in themselves robust under reducing conditions. In this work, we introduce a strategy for stability enhancement through conformational tuning, where incorporating additional substituents on the nitroxide ring effects a shift towards highly stable closed spirocyclic conformations, as indicated by X-ray crystallography and density functional theory (DFT) calculations. Closed spirocyclohexyl nitroxides exhibit dramatically improved stability towards reduction by ascorbate, while maintaining long relaxation times in electron paramagnetic resonance (EPR) spectroscopy. These findings have important implications for the future design of new nitroxide-based spin labels and imaging agents.
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Affiliation(s)
- Mateusz P Sowiński
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Sahil Gahlawat
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
- Hylleraas Center for Quantum Molecular Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Bjarte A Lund
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Anna-Luisa Warnke
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Kathrin H Hopmann
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Janet E Lovett
- SUPA, School of Physics and Astronomy and BSRC, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK
| | - Marius M Haugland
- Department of Chemistry, UiT The Arctic University of Norway, 9037, Tromsø, Norway.
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2
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Gallez B. The Role of Imaging Biomarkers to Guide Pharmacological Interventions Targeting Tumor Hypoxia. Front Pharmacol 2022; 13:853568. [PMID: 35910347 PMCID: PMC9335493 DOI: 10.3389/fphar.2022.853568] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 06/23/2022] [Indexed: 12/12/2022] Open
Abstract
Hypoxia is a common feature of solid tumors that contributes to angiogenesis, invasiveness, metastasis, altered metabolism and genomic instability. As hypoxia is a major actor in tumor progression and resistance to radiotherapy, chemotherapy and immunotherapy, multiple approaches have emerged to target tumor hypoxia. It includes among others pharmacological interventions designed to alleviate tumor hypoxia at the time of radiation therapy, prodrugs that are selectively activated in hypoxic cells or inhibitors of molecular targets involved in hypoxic cell survival (i.e., hypoxia inducible factors HIFs, PI3K/AKT/mTOR pathway, unfolded protein response). While numerous strategies were successful in pre-clinical models, their translation in the clinical practice has been disappointing so far. This therapeutic failure often results from the absence of appropriate stratification of patients that could benefit from targeted interventions. Companion diagnostics may help at different levels of the research and development, and in matching a patient to a specific intervention targeting hypoxia. In this review, we discuss the relative merits of the existing hypoxia biomarkers, their current status and the challenges for their future validation as companion diagnostics adapted to the nature of the intervention.
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Affiliation(s)
- Bernard Gallez
- Biomedical Magnetic Resonance Research Group, Louvain Drug Research Institute, Université Catholique de Louvain (UCLouvain), Brussels, Belgium
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3
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Rane V. Harnessing Electron Spin Hyperpolarization in Chromophore-Radical Spin Probes for Subcellular Resolution in Electron Paramagnetic Resonance Imaging: Concept and Feasibility. J Phys Chem B 2022; 126:2715-2728. [PMID: 35353514 DOI: 10.1021/acs.jpcb.1c10920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Obtaining a subcellular resolution for biological samples doped with stable radicals at room temperature (RT) is a long-sought goal in electron paramagnetic resonance imaging (EPRI). The spatial resolution in current EPRI methods is constrained either because of low electron spin polarization at RT or the experimental limitations associated with the field gradients and the radical linewidth. Inspired by the recent demonstration of a large electron spin hyperpolarization in chromophore-nitroxyl spin probe molecules, the present work proposes a novel optically hyperpolarized EPR imaging (OH-EPRI) method, which combines the optical method of two-photon confocal microscopy for hyperpolarization generation and the rapid scan (RS) EPR method for signal detection. An important aspect of OH-EPRI is that it is not limited by the abovementioned restrictions of conventional EPRI since the large hyperpolarization in the spin probes overcomes the poor thermal spin polarization at RT, and the use of two-photon optical excitation of the chromophore naturally generates the required spatial resolution, without the need for any magnetic field gradient. Simulations based on time-dependent Bloch equations, which took into account both the RS field modulation and the hyperpolarization generation by optical means, were performed to examine the feasibility of OH-EPRI. The simulation results revealed that a spatial resolution of up to 2 fL can be achieved in OH-EPRI at RT under in vitro conditions. Notably, the majority of the requirements for an OH-EPRI experiment can be fulfilled by the currently available technologies, thereby paving the way for its easy implementation. Thus, the proposed method could potentially bridge the sensitivity gap between the optical and magnetic imaging techniques.
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Affiliation(s)
- Vinayak Rane
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
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4
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Kimura K, Iguchi N, Nakano H, Yasui H, Matsumoto S, Inanami O, Hirata H. Redox-Sensitive Mapping of a Mouse Tumor Model Using Sparse Projection Sampling of Electron Paramagnetic Resonance. Antioxid Redox Signal 2022; 36:57-69. [PMID: 33847172 PMCID: PMC8823265 DOI: 10.1089/ars.2021.0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 03/08/2021] [Accepted: 04/03/2021] [Indexed: 11/16/2022]
Abstract
Aims: This work aimed to establish an accelerated imaging system for redox-sensitive mapping in a mouse tumor model using electron paramagnetic resonance (EPR) and nitroxyl radicals. Results: Sparse sampling of EPR spectral projections was demonstrated for a solution phantom. The reconstructed three-dimensional (3D) images with filtered back-projection (FBP) and compressed sensing image reconstruction were quantitatively assessed for the solution phantom. Mouse xenograft models of a human-derived pancreatic ductal adenocarcinoma cell line, MIA PaCa-2, were also measured for redox-sensitive mapping with the sparse sampling technique. Innovation: A short-lifetime redox-sensitive nitroxyl radical (15N-labeled perdeuterated Tempone) could be measured to map the decay rates of the EPR signals for the mouse xenograft models. Acceleration of 3D EPR image acquisition broadened the choices of nitroxyl radical probes with various redox sensitivities to biological environments. Conclusion: Sparse sampling of EPR spectral projections accelerated image acquisition in the 3D redox-sensitive mapping of mouse tumor-bearing legs fourfold compared with conventional image acquisition with FBP. Antioxid. Redox Signal. 36, 57-69.
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Affiliation(s)
- Kota Kimura
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Nami Iguchi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Hitomi Nakano
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Osamu Inanami
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
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5
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Swartz HM, Flood AB, Williams BB, Pogue BW, Schaner PE, Vaupel P. What Is the Meaning of an Oxygen Measurement? : Analysis of Methods Purporting to Measure Oxygen in Targeted Tissues. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1269:301-308. [PMID: 33966234 DOI: 10.1007/978-3-030-48238-1_48] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Clinical measurements of O2 in tissues will inevitably provide data that are at best aggregated and will not reflect the inherent heterogeneity of O2 in tissues over space and time. Additionally, the nature of all existing techniques to measure O2 results in complex sampling of the volume that is sensed by the technique. By recognizing these potential limitations of the measures, one can focus on the very important and useful information that can be obtained from these techniques, especially data about factors that can change levels of O2 and then exploit these changes diagnostically and therapeutically. The clinical utility of such data ultimately needs to be verified by careful studies of outcomes related to the measured changes in levels of O2.
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Affiliation(s)
- Harold M Swartz
- Department of Radiology, Dartmouth Medical School, Hanover, NH, USA.
- Department of Radiation Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.
| | - Ann Barry Flood
- Department of Radiology, Dartmouth Medical School, Hanover, NH, USA
| | - Benjamin B Williams
- Department of Radiation Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Philip E Schaner
- Department of Radiation Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Peter Vaupel
- Department of Radiation Oncology, University Medical Center, University of Freiburg, Freiburg, Germany
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Anemone A, Consolino L, Arena F, Capozza M, Longo DL. Imaging tumor acidosis: a survey of the available techniques for mapping in vivo tumor pH. Cancer Metastasis Rev 2020; 38:25-49. [PMID: 30762162 PMCID: PMC6647493 DOI: 10.1007/s10555-019-09782-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cancer cells are characterized by a metabolic shift in cellular energy production, orchestrated by the transcription factor HIF-1α, from mitochondrial oxidative phosphorylation to increased glycolysis, regardless of oxygen availability (Warburg effect). The constitutive upregulation of glycolysis leads to an overproduction of acidic metabolic products, resulting in enhanced acidification of the extracellular pH (pHe ~ 6.5), which is a salient feature of the tumor microenvironment. Despite the importance of pH and tumor acidosis, there is currently no established clinical tool available to image the spatial distribution of tumor pHe. The purpose of this review is to describe various imaging modalities for measuring intracellular and extracellular tumor pH. For each technique, we will discuss main advantages and limitations, pH accuracy and sensitivity of the applied pH-responsive probes and potential translatability to the clinic. Particular attention is devoted to methods that can provide pH measurements at high spatial resolution useful to address the task of tumor heterogeneity and to studies that explored tumor pH imaging for assessing treatment response to anticancer therapies.
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Affiliation(s)
- Annasofia Anemone
- Molecular Imaging Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, Italy
| | - Lorena Consolino
- Molecular Imaging Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, Italy
| | - Francesca Arena
- Institute of Biostructures and Bioimaging (IBB), Italian National Research Council (CNR), Via Nizza 52, Turin, Italy.,Center for Preclinical Imaging, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Ribes 5, Colleretto Giacosa, Italy
| | - Martina Capozza
- Center for Preclinical Imaging, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Ribes 5, Colleretto Giacosa, Italy
| | - Dario Livio Longo
- Molecular Imaging Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, Italy. .,Institute of Biostructures and Bioimaging (IBB), Italian National Research Council (CNR), Via Nizza 52, Turin, Italy.
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7
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Waterton JC, Hines CDG, Hockings PD, Laitinen I, Ziemian S, Campbell S, Gottschalk M, Green C, Haase M, Hassemer K, Juretschke HP, Koehler S, Lloyd W, Luo Y, Mahmutovic Persson I, O'Connor JPB, Olsson LE, Pindoria K, Schneider JE, Sourbron S, Steinmann D, Strobel K, Tadimalla S, Teh I, Veltien A, Zhang X, Schütz G. Repeatability and reproducibility of longitudinal relaxation rate in 12 small-animal MRI systems. Magn Reson Imaging 2019; 59:121-129. [PMID: 30872166 PMCID: PMC6477178 DOI: 10.1016/j.mri.2019.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 01/29/2019] [Accepted: 03/08/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Many translational MR biomarkers derive from measurements of the water proton longitudinal relaxation rate R1, but evidence for between-site reproducibility of R1 in small-animal MRI is lacking. OBJECTIVE To assess R1 repeatability and multi-site reproducibility in phantoms for preclinical MRI. METHODS R1 was measured by saturation recovery in 2% agarose phantoms with five nickel chloride concentrations in 12 magnets at 5 field strengths in 11 centres on two different occasions within 1-13 days. R1 was analysed in three different regions of interest, giving 360 measurements in total. Root-mean-square repeatability and reproducibility coefficients of variation (CoV) were calculated. Propagation of reproducibility errors into 21 translational MR measurements and biomarkers was estimated. Relaxivities were calculated. Dynamic signal stability was also measured. RESULTS CoV for day-to-day repeatability (N = 180 regions of interest) was 2.34% and for between-centre reproducibility (N = 9 centres) was 1.43%. Mostly, these do not propagate to biologically significant between-centre error, although a few R1-based MR biomarkers were found to be quite sensitive even to such small errors in R1, notably in myocardial fibrosis, in white matter, and in oxygen-enhanced MRI. The relaxivity of aqueous Ni2+ in 2% agarose varied between 0.66 s-1 mM-1 at 3 T and 0.94 s-1 mM-1 at 11.7T. INTERPRETATION While several factors affect the reproducibility of R1-based MR biomarkers measured preclinically, between-centre propagation of errors arising from intrinsic equipment irreproducibility should in most cases be small. However, in a few specific cases exceptional efforts might be required to ensure R1-reproducibility.
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Affiliation(s)
- John C Waterton
- Bioxydyn Ltd, Manchester Science Park, Rutherford House, Pencroft Way, MANCHESTER M15 6SZ, United Kingdom; Centre for Imaging Sciences, Division of Informatics Imaging & Data Sciences, School of Health Sciences, Faculty of Biology Medicine & Health, University of Manchester, Manchester Academic Health Sciences Centre, MANCHESTER M13 9PL, United Kingdom.
| | | | - Paul D Hockings
- Antaros Medical, BioVenture Hub, 43183 Mölndal, Sweden; MedTech West, Chalmers University of Technology, Gothenburg, Sweden.
| | - Iina Laitinen
- Sanofi-Aventis Deutschland GmbH, R&D TIM - Bioimaging Germany, Industriepark Höchst, D-65926 Frankfurt am Main, Germany.
| | - Sabina Ziemian
- Bayer AG, Research and Development, Pharmaceuticals, MR and CT Contrast Media Research, Müllerstraße 178, D-13353 Berlin, Germany.
| | - Simon Campbell
- In-Vivo Bioimaging UK, RD Platform Technology & Science, GSK Medicines Research Centre, Gunnels Wood Road, STEVENAGE, Hertfordshire, SG1 2NY, United Kingdom.
| | - Michael Gottschalk
- Lund University BioImaging Center, Klinikgatan 32, SE-222-42 Lund, Sweden.
| | - Claudia Green
- Bayer AG, Research and Development, Pharmaceuticals, MR and CT Contrast Media Research, Müllerstraße 178, D-13353 Berlin, Germany.
| | - Michael Haase
- In-Vivo Bioimaging UK, RD Platform Technology & Science, GSK Medicines Research Centre, Gunnels Wood Road, STEVENAGE, Hertfordshire, SG1 2NY, United Kingdom.
| | - Katja Hassemer
- Sanofi-Aventis Deutschland GmbH, R&D TIM - Bioimaging Germany, Industriepark Höchst, D-65926 Frankfurt am Main, Germany.
| | - Hans-Paul Juretschke
- Sanofi-Aventis Deutschland GmbH, R&D TIM - Bioimaging Germany, Industriepark Höchst, D-65926 Frankfurt am Main, Germany
| | - Sascha Koehler
- Bruker BioSpin MRI GmbH, Rudolf-Plank-Straße 23, D-76275 Ettlingen, Germany.
| | - William Lloyd
- Centre for Imaging Sciences, Division of Informatics Imaging & Data Sciences, School of Health Sciences, Faculty of Biology Medicine & Health, University of Manchester, Manchester Academic Health Sciences Centre, MANCHESTER M13 9PL, United Kingdom.
| | - Yanping Luo
- iSAT Discovery, Abbvie, 1 North Waukegan Road, North Chicago, IL, 60064-1802, United States of America.
| | - Irma Mahmutovic Persson
- Department of Translational Sciences, Medical Radiation Physics, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden.
| | - James P B O'Connor
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology Medicine & Health, University of Manchester, Manchester Academic Health Sciences Centre, MANCHESTER M20 4BX, United Kingdom. james.o'
| | - Lars E Olsson
- Department of Translational Sciences, Medical Radiation Physics, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden.
| | - Kashmira Pindoria
- In-Vivo Bioimaging UK, RD Platform Technology & Science, GSK Medicines Research Centre, Gunnels Wood Road, STEVENAGE, Hertfordshire, SG1 2NY, United Kingdom.
| | - Jurgen E Schneider
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Steven Sourbron
- Leeds Imaging Biomarkers Group, Department of Biomedical Imaging Sciences, University of Leeds, LIGHT Labs, Clarendon Way, LEEDS LS2 9JT, United Kingdom.
| | - Denise Steinmann
- Sanofi-Aventis Deutschland GmbH, R&D TIM - Bioimaging Germany, Industriepark Höchst, D-65926 Frankfurt am Main, Germany.
| | - Klaus Strobel
- Bruker BioSpin MRI GmbH, Rudolf-Plank-Straße 23, D-76275 Ettlingen, Germany.
| | - Sirisha Tadimalla
- Leeds Imaging Biomarkers Group, Department of Biomedical Imaging Sciences, University of Leeds, LIGHT Labs, Clarendon Way, LEEDS LS2 9JT, United Kingdom.
| | - Irvin Teh
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Andor Veltien
- Radboud university medical center, Radiology (766), P.O.Box 9101, 6500, HB, Nijmegen, the Netherlands.
| | - Xiaomeng Zhang
- iSAT Discovery, Abbvie, 1 North Waukegan Road, North Chicago, IL, 60064-1802, United States of America.
| | - Gunnar Schütz
- Bayer AG, Research and Development, Pharmaceuticals, MR and CT Contrast Media Research, Müllerstraße 178, D-13353 Berlin, Germany.
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Molecular Probes for Evaluation of Oxidative Stress by In Vivo EPR Spectroscopy and Imaging: State-of-the-Art and Limitations. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010013] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oxidative stress, defined as a misbalance between the production of reactive oxygen species and the antioxidant defenses of the cell, appears as a critical factor either in the onset or in the etiology of many pathological conditions. Several methods of detection exist. However, they usually rely on ex vivo evaluation or reports on the status of living tissues only up to a few millimeters in depth, while a whole-body, real-time, non-invasive monitoring technique is required for early diagnosis or as an aid to therapy (to monitor the action of a drug). Methods based on electron paramagnetic resonance (EPR), in association with molecular probes based on aminoxyl radicals (nitroxides) or hydroxylamines especially, have emerged as very promising to meet these standards. The principles involve monitoring the rate of decrease or increase of the EPR signal in vivo after injection of the nitroxide or the hydroxylamine probe, respectively, in a pathological versus a control situation. There have been many successful applications in various rodent models. However, current limitations lie in both the field of the technical development of the spectrometers and the molecular probes. The scope of this review will mainly focus on the latter.
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9
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Brain Redox Imaging Using In Vivo Electron Paramagnetic Resonance Imaging and Nitroxide Imaging Probes. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Reactive oxygen species (ROS) are produced by living organisms as a result of normal cellular metabolism. Under normal physiological conditions, oxidative damage is prevented by the regulation of ROS by the antioxidant network. However, increased ROS and decreased antioxidant defense may contribute to many brain disorders, such as stroke, Parkinson’s disease, and Alzheimer’s disease. Noninvasive assessment of brain redox status is necessary for monitoring the disease state and the oxidative damage. Continuous-wave electron paramagnetic resonance (CW-EPR) imaging using redox-sensitive imaging probes, such as nitroxides, is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. For conventional CW-EPR imaging, however, poor signal-to-noise ratio, low acquisition efficiency, and lack of anatomic visualization limit its ability to achieve three-dimensional redox mapping of small rodent brains. In this review, we discuss the instrumentation and coregistration of EPR images to anatomical images and appropriate nitroxide imaging probes, all of which are needed for a sophisticated in vivo EPR imager for all rodents. Using new EPR imaging systems, site-specific distribution and kinetics of nitroxide imaging probes in rodent brains can be obtained more accurately, compared to previous EPR imaging systems. We also describe the redox imaging studies of animal models of brain disease using newly developed EPR imaging.
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10
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Gorodetskii AA, Eubank TD, Driesschaert B, Poncelet M, Ellis E, Khramtsov VV, Bobko AA. Oxygen-induced leakage of spin polarization in Overhauser-enhanced magnetic resonance imaging: Application for oximetry in tumors. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 297:42-50. [PMID: 30359906 PMCID: PMC6289650 DOI: 10.1016/j.jmr.2018.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/03/2018] [Accepted: 10/09/2018] [Indexed: 06/08/2023]
Abstract
Overhauser-enhanced Magnetic Resonance Imaging (OMRI) is a double resonance technique applied for oxygen imaging in aqueous samples and biological tissues. In this report, we present an improved OMRI approach of oxygen measurement using the single line "Finland" trityl spin probe. Compared to a traditional approach, we introduced an additional mechanism of leakage of spin polarization due to an interaction of a spin system with oxygen. The experimental comparison of the new approach with an oxygen-dependent leakage factor to a traditional approach performed in phantom samples in vitro, and mouse tumor model in vivo, shows improved accuracy of determination of oxygen and contrast agent concentrations.
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Affiliation(s)
- Artem A Gorodetskii
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; N.N. Voroztsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia
| | - Timothy D Eubank
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; Department of Microbiology, Immunology & Cell Biology, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; West Virginia University Cancer Institute, Morgantown, WV 26506, USA
| | - Benoit Driesschaert
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV 26506, USA; West Virginia University Cancer Institute, Morgantown, WV 26506, USA
| | - Martin Poncelet
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, WV 26506, USA
| | - Emily Ellis
- Department of Microbiology, Immunology & Cell Biology, West Virginia University, School of Medicine, Morgantown, WV 26506, USA
| | - Valery V Khramtsov
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; West Virginia University Cancer Institute, Morgantown, WV 26506, USA.
| | - Andrey A Bobko
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; West Virginia University Cancer Institute, Morgantown, WV 26506, USA.
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11
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Khramtsov VV. In Vivo Molecular Electron Paramagnetic Resonance-Based Spectroscopy and Imaging of Tumor Microenvironment and Redox Using Functional Paramagnetic Probes. Antioxid Redox Signal 2018; 28:1365-1377. [PMID: 29132215 PMCID: PMC5910053 DOI: 10.1089/ars.2017.7329] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE A key role of the tumor microenvironment (TME) in cancer progression, treatment resistance, and as a target for therapeutic intervention is increasingly appreciated. Among important physiological components of the TME are tissue hypoxia, acidosis, high reducing capacity, elevated concentrations of intracellular glutathione (GSH), and interstitial inorganic phosphate (Pi). Noninvasive in vivo pO2, pH, GSH, Pi, and redox assessment provide unique insights into biological processes in the TME, and may serve as a tool for preclinical screening of anticancer drugs and optimizing TME-targeted therapeutic strategies. Recent Advances: A reasonable radiofrequency penetration depth in living tissues and progress in development of functional paramagnetic probes make low-field electron paramagnetic resonance (EPR)-based spectroscopy and imaging the most appropriate approaches for noninvasive assessment of the TME parameters. CRITICAL ISSUES Here we overview the current status of EPR approaches used in combination with functional paramagnetic probes that provide quantitative information on chemical TME and redox (pO2, pH, redox status, Pi, and GSH). In particular, an application of a recently developed dual-function pH and redox nitroxide probe and multifunctional trityl probe provides unsurpassed opportunity for in vivo concurrent measurements of several TME parameters in preclinical studies. The measurements of several parameters using a single probe allow for their correlation analyses independent of probe distribution and time of measurements. FUTURE DIRECTIONS The recent progress in clinical EPR instrumentation and development of biocompatible paramagnetic probes for in vivo multifunctional TME profiling eventually will make possible translation of these EPR techniques into clinical settings to improve prediction power of early diagnostics for the malignant transition and for future rational design of TME-targeted anticancer therapeutics. Antioxid. Redox Signal. 28, 1365-1377.
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Affiliation(s)
- Valery V Khramtsov
- 1 In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University , Morgantown, West Virginia.,2 Department of Biochemistry, West Virginia University School of Medicine , Morgantown, West Virginia
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12
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Rinard GA, Quine RW, Buchanan LA, Eaton SS, Eaton GR, Epel B, Sundramoorthy SV, Halpern HJ. Resonators for In Vivo Imaging: Practical Experience. APPLIED MAGNETIC RESONANCE 2017; 48:1227-1247. [PMID: 29391664 PMCID: PMC5788320 DOI: 10.1007/s00723-017-0947-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Resonators for preclinical electron paramagnetic resonance imaging have been designed primarily for rodents and rabbits and have internal diameters between 16 and 51 mm. Lumped circuit resonators include loop-gap, Alderman-Grant, and saddle coil topologies and surface coils. Bimodal resonators are useful for isolating the detected signal from incident power and reducing dead time in pulse experiments. Resonators for continuous wave, rapid scan, and pulse experiments are described. Experience at the University of Chicago and University of Denver in design of resonators for in vivo imaging is summarized.
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Affiliation(s)
- George A Rinard
- Center for EPR Imaging In Vivo Physiology, Department of Chemistry and Biochemistry and School of Engineering and Computer Science, University of Denver, Denver, CO 80210, USA
| | - Richard W Quine
- Center for EPR Imaging In Vivo Physiology, Department of Chemistry and Biochemistry and School of Engineering and Computer Science, University of Denver, Denver, CO 80210, USA
| | - Laura A Buchanan
- Center for EPR Imaging In Vivo Physiology, Department of Chemistry and Biochemistry and School of Engineering and Computer Science, University of Denver, Denver, CO 80210, USA
| | - Sandra S Eaton
- Center for EPR Imaging In Vivo Physiology, Department of Chemistry and Biochemistry and School of Engineering and Computer Science, University of Denver, Denver, CO 80210, USA
| | - Gareth R Eaton
- Center for EPR Imaging In Vivo Physiology, Department of Chemistry and Biochemistry and School of Engineering and Computer Science, University of Denver, Denver, CO 80210, USA
| | - Boris Epel
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
| | - Subramanian V Sundramoorthy
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
| | - Howard J Halpern
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
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13
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Komarov DA, Hirata H. Fast backprojection-based reconstruction of spectral-spatial EPR images from projections with the constant sweep of a magnetic field. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 281:44-50. [PMID: 28549338 DOI: 10.1016/j.jmr.2017.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 06/07/2023]
Abstract
In this paper, we introduce a procedure for the reconstruction of spectral-spatial EPR images using projections acquired with the constant sweep of a magnetic field. The application of a constant field-sweep and a predetermined data sampling rate simplifies the requirements for EPR imaging instrumentation and facilitates the backprojection-based reconstruction of spectral-spatial images. The proposed approach was applied to the reconstruction of a four-dimensional numerical phantom and to actual spectral-spatial EPR measurements. Image reconstruction using projections with a constant field-sweep was three times faster than the conventional approach with the application of a pseudo-angle and a scan range that depends on the applied field gradient. Spectral-spatial EPR imaging with a constant field-sweep for data acquisition only slightly reduces the signal-to-noise ratio or functional resolution of the resultant images and can be applied together with any common backprojection-based reconstruction algorithm.
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Affiliation(s)
- Denis A Komarov
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan.
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14
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Abstract
Molecular oxygen (O2) is essential to brain function and mechanisms necessary to regulate variations in delivery or utilization of O2 are crucial to support normal brain homeostasis, physiology and energy metabolism. Any imbalance in cerebral tissue partial pressure of O2 (pO2) levels may lead to pathophysiological complications including increased reactive O2 species generation leading to oxidative stress when tissue O2 level is too high or too low. Accordingly, the need for oximetry methods, which assess cerebral pO2in vivo and in real time, is imperative to understand the role of O2 in various metabolic and disease states, including the effects of treatment and therapy options. In this review, we provide a brief overview of the common in vivo oximetry methodologies for measuring cerebral pO2. We discuss the advantages and limitations of oximetry methodologies to measure cerebral pO2in vivo followed by a more in-depth review of electron paramagnetic resonance oximetry spectroscopy and imaging using several examples of current electron paramagnetic resonance oximetry applications in the brain.
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Affiliation(s)
- John M Weaver
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.,Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.,Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.,Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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15
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Kubota H, Komarov DA, Yasui H, Matsumoto S, Inanami O, Kirilyuk IA, Khramtsov VV, Hirata H. Feasibility of in vivo three-dimensional T 2* mapping using dicarboxy-PROXYL and CW-EPR-based single-point imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 30:291-298. [PMID: 28063096 DOI: 10.1007/s10334-016-0606-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/13/2016] [Accepted: 12/22/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The aim of this study was to demonstrate the feasibility of in vivo three-dimensional (3D) relaxation time T 2* mapping of a dicarboxy-PROXYL radical using continuous-wave electron paramagnetic resonance (CW-EPR) imaging. MATERIALS AND METHODS Isotopically substituted dicarboxy-PROXYL radicals, 3,4-dicarboxy-2,2,5,5-tetra(2H3)methylpyrrolidin-(3,4-2H2)-(1-15N)-1-oxyl (2H,15N-DCP) and 3,4-dicarboxy-2,2,5,5-tetra(2H3)methylpyrrolidin-(3,4-2H2)-1-oxyl (2H-DCP), were used in the study. A clonogenic cell survival assay was performed with the 2H-DCP radical using squamous cell carcinoma (SCC VII) cells. The time course of EPR signal intensities of intravenously injected 2H,15N-DCP and 2H-DCP radicals were determined in tumor-bearing hind legs of mice (C3H/HeJ, male, n = 5). CW-EPR-based single-point imaging (SPI) was performed for 3D T 2* mapping. RESULTS 2H-DCP radical did not exhibit cytotoxicity at concentrations below 10 mM. The in vivo half-life of 2H,15N-DCP in tumor tissues was 24.7 ± 2.9 min (mean ± standard deviation [SD], n = 5). The in vivo time course of the EPR signal intensity of the 2H,15N-DCP radical showed a plateau of 10.2 ± 1.2 min (mean ± SD) where the EPR signal intensity remained at more than 90% of the maximum intensity. During the plateau, in vivo 3D T 2* maps with 2H,15N-DCP were obtained from tumor-bearing hind legs, with a total acquisition time of 7.5 min. CONCLUSION EPR signals of 2H,15N-DCP persisted long enough after bolus intravenous injection to conduct in vivo 3D T 2* mapping with CW-EPR-based SPI.
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Affiliation(s)
- Harue Kubota
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Denis A Komarov
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Hironobu Yasui
- Central Institute of Isotope Science, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-0815, Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Osamu Inanami
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo, 060-0818, Japan
| | - Igor A Kirilyuk
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, 9, Ac. Lavrentieva Ave., Novosibirsk, 630090, Russia
| | - Valery V Khramtsov
- Department of Biochemistry, West Virginia University, Robert C. Byrd Health Sciences Center, 1 Medical Center Drive, Morgantown, WV, 26506, USA
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan.
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16
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Ahmad R, Samouilov A, Zweier JL. Accelerated dynamic EPR imaging using fast acquisition and compressive recovery. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 273:105-112. [PMID: 27821290 PMCID: PMC5130408 DOI: 10.1016/j.jmr.2016.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/30/2016] [Accepted: 10/01/2016] [Indexed: 06/06/2023]
Abstract
Electron paramagnetic resonance (EPR) allows quantitative imaging of tissue redox status, which provides important information about ischemic syndromes, cancer and other pathologies. For continuous wave EPR imaging, however, poor signal-to-noise ratio and low acquisition efficiency limit its ability to image dynamic processes in vivo including tissue redox, where conditions can change rapidly. Here, we present a data acquisition and processing framework that couples fast acquisition with compressive sensing-inspired image recovery to enable EPR-based redox imaging with high spatial and temporal resolutions. The fast acquisition (FA) allows collecting more, albeit noisier, projections in a given scan time. The composite regularization based processing method, called spatio-temporal adaptive recovery (STAR), not only exploits sparsity in multiple representations of the spatio-temporal image but also adaptively adjusts the regularization strength for each representation based on its inherent level of the sparsity. As a result, STAR adjusts to the disparity in the level of sparsity across multiple representations, without introducing any tuning parameter. Our simulation and phantom imaging studies indicate that a combination of fast acquisition and STAR (FASTAR) enables high-fidelity recovery of volumetric image series, with each volumetric image employing less than 10 s of scan. In addition to image fidelity, the time constants derived from FASTAR also match closely to the ground truth even when a small number of projections are used for recovery. This development will enhance the capability of EPR to study fast dynamic processes that cannot be investigated using existing EPR imaging techniques.
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17
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Weaver J, Burks SR, Liu KJ, Kao JPY, Rosen GM. In vivo EPR oximetry using an isotopically-substituted nitroxide: Potential for quantitative measurement of tissue oxygen. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 271:68-74. [PMID: 27567323 PMCID: PMC5266518 DOI: 10.1016/j.jmr.2016.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/12/2016] [Accepted: 08/15/2016] [Indexed: 06/06/2023]
Abstract
Variations in brain oxygen (O2) concentration can have profound effects on brain physiology. Thus, the ability to quantitate local O2 concentrations noninvasively in vivo could significantly enhance understanding of several brain pathologies. However, quantitative O2 mapping in the brain has proven difficult. The electron paramagnetic resonance (EPR) spectra of nitroxides are sensitive to molecular O2 and can be used to estimate O2 concentrations in aqueous media. We recently synthesized labile-ester-containing nitroxides, such as 3-acetoxymethoxycarbonyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 4), which accumulate in cerebral tissue after in situ hydrolysis, and thus enable spatial mapping of O2 concentrations in the mouse brain by EPR imaging. In an effort to improve O2 quantitation, we prepared 3-acetoxymethoxycarbonyl-2,2,5,5-tetra((2)H3)methyl-1-(3,4,4-(2)H3,1-(15)N)pyrrolidinyloxyl (nitroxide 2), which proved to be a more sensitive probe than its normo-isotopic version for quantifying O2 in aqueous solutions of various O2 concentrations. We now demonstrate that this isotopically substituted nitroxide is ∼2-fold more sensitive in vivo than the normo-isotopic nitroxide 4. Moreover, in vitro and in vivo EPR spectral-spatial imaging results with nitroxide 2 demonstrate significant improvement in resolution, reconstruction and spectral response to local O2 concentrations in cerebral tissue. Thus, isotopic-substituted nitroxides, such as 2, are excellent sensors for in vivo O2 quantitation in tissues, such as the brain.
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Affiliation(s)
- John Weaver
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States; Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, United States.
| | - Scott R Burks
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Center for EPR Imaging In Vivo Physiology, University of Maryland, Baltimore, MD 21201, United States
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States; Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, United States
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Center for EPR Imaging In Vivo Physiology, University of Maryland, Baltimore, MD 21201, United States
| | - Gerald M Rosen
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States; Center for EPR Imaging In Vivo Physiology, University of Maryland, Baltimore, MD 21201, United States; Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
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18
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Maulucci G, Bačić G, Bridal L, Schmidt HH, Tavitian B, Viel T, Utsumi H, Yalçın AS, De Spirito M. Imaging Reactive Oxygen Species-Induced Modifications in Living Systems. Antioxid Redox Signal 2016; 24:939-58. [PMID: 27139586 PMCID: PMC4900226 DOI: 10.1089/ars.2015.6415] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
SIGNIFICANCE Reactive Oxygen Species (ROS) may regulate signaling, ion channels, transcription factors, and biosynthetic processes. ROS-related diseases can be due to either a shortage or an excess of ROS. RECENT ADVANCES Since the biological activity of ROS depends on not only concentration but also spatiotemporal distribution, real-time imaging of ROS, possibly in vivo, has become a need for scientists, with potential for clinical translation. New imaging techniques as well as new contrast agents in clinically established modalities were developed in the previous decade. CRITICAL ISSUES An ideal imaging technique should determine ROS changes with high spatio-temporal resolution, detect physiologically relevant variations in ROS concentration, and provide specificity toward different redox couples. Furthermore, for in vivo applications, bioavailability of sensors, tissue penetration, and a high signal-to-noise ratio are additional requirements to be satisfied. FUTURE DIRECTIONS None of the presented techniques fulfill all requirements for clinical translation. The obvious way forward is to incorporate anatomical and functional imaging into a common hybrid-imaging platform. Antioxid. Redox Signal. 24, 939-958.
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Affiliation(s)
- Giuseppe Maulucci
- 1 Institute of Physics, Catholic University of Sacred Heart , Roma, Italy
| | - Goran Bačić
- 2 Faculty of Physical Chemistry, University of Belgrade , Belgrade, Serbia
| | - Lori Bridal
- 3 Laboratoire d'Imagerie Biomédicale, Sorbonne Universités and UPMC Univ Paris 06 and CNRS and INSERM , Paris, France
| | - Harald Hhw Schmidt
- 4 Department of Pharmacology and Personalised Medicine, CARIM, Faculty of Health, Medicine & Life Science, Maastricht University , Maastricht, the Netherlands
| | - Bertrand Tavitian
- 5 Laboratoire de Recherche en Imagerie, Université Paris Descartes, Hôpital Européen Georges Pompidou , Service de Radiologie, Paris, France
| | - Thomas Viel
- 5 Laboratoire de Recherche en Imagerie, Université Paris Descartes, Hôpital Européen Georges Pompidou , Service de Radiologie, Paris, France
| | - Hideo Utsumi
- 6 Innovation Center for Medical Redox Navigation, Kyushu University , Fukuoka, Japan
| | - A Süha Yalçın
- 7 Department of Biochemistry, School of Medicine, Marmara University , İstanbul, Turkey
| | - Marco De Spirito
- 1 Institute of Physics, Catholic University of Sacred Heart , Roma, Italy
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19
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Bačić G, Pavićević A, Peyrot F. In vivo evaluation of different alterations of redox status by studying pharmacokinetics of nitroxides using magnetic resonance techniques. Redox Biol 2015; 8:226-42. [PMID: 26827126 PMCID: PMC4753396 DOI: 10.1016/j.redox.2015.10.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/25/2015] [Indexed: 12/22/2022] Open
Abstract
Free radicals, particularly reactive oxygen species (ROS), are involved in various pathologies, injuries related to radiation, ischemia-reperfusion or ageing. Unfortunately, it is virtually impossible to directly detect free radicals in vivo, but the redox status of the whole organism or particular organ can be studied in vivo by using magnetic resonance techniques (EPR and MRI) and paramagnetic stable free radicals - nitroxides. Here we review results obtained in vivo following the pharmacokinetics of nitroxides on experimental animals (and a few in humans) under various conditions. The focus was on conditions where the redox status has been altered by induced diseases or harmful agents, clearly demonstrating that various EPR/MRI/nitroxide combinations can reliably detect metabolically induced changes in the redox status of organs. These findings can improve our understanding of oxidative stress and provide a basis for studying the effectiveness of interventions aimed to modulate oxidative stress. Also, we anticipate that the in vivo EPR/MRI approach in studying the redox status can play a vital role in the clinical management of various pathologies in the years to come providing the development of adequate equipment and probes.
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Affiliation(s)
- Goran Bačić
- EPR Laboratory, Faculty of Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia
| | - Aleksandra Pavićević
- EPR Laboratory, Faculty of Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia
| | - Fabienne Peyrot
- LCBPT, UMR 8601 CNRS - Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; ESPE of Paris, Paris Sorbonne Université, 75016 Paris, France
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20
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Abstract
Rapid-scan electron paramagnetic resonance is based on continuous direct detection of the spin response as the magnetic field is scanned upfield and downfield through resonance thousands of times per second. The method provides improved signal-to-noise for a wide range of samples, including rapidly tumbling and immobilized radicals. This chapter provides an introduction to the method and practical examples of implementation for organic radicals.
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Affiliation(s)
- Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA.
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21
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Caglieris F, Melone L, Canepa F, Lamura G, Castiglione F, Ferro M, Malpezzi L, Mele A, Punta C, Franchi P, Lucarini M, Rossi B, Trotta F. Effective magnetic moment in cyclodextrin–polynitroxides: potential supramolecular vectors for magnetic resonance imaging. RSC Adv 2015. [DOI: 10.1039/c5ra14597j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hepta-TEMPO β-CD has a molecular effective magnetic moment of 4.2 μB that is responsible of a NMR relaxivity up to 1.60 mm−1 s−1, not far from the values reported for Gd-based contrast agents, thus resulting a promising candidates as non-toxic MRI contrast agents.
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22
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Biller JR, Tseitlin M, Quine RW, Rinard GA, Weismiller HA, Elajaili H, Rosen GM, Kao JPY, Eaton SS, Eaton GR. Imaging of nitroxides at 250MHz using rapid-scan electron paramagnetic resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 242:162-8. [PMID: 24650729 PMCID: PMC4081024 DOI: 10.1016/j.jmr.2014.02.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/15/2014] [Accepted: 02/18/2014] [Indexed: 05/12/2023]
Abstract
Projections for 2D spectral-spatial images were obtained by continuous wave and rapid-scan electron paramagnetic resonance using a bimodal cross-loop resonator at 251MHz. The phantom consisted of three 4mm tubes containing different (15)N,(2)H-substituted nitroxides. Rapid-scan and continuous wave images were obtained with 5min total acquisition times. For comparison, images also were obtained with 29s acquisition time for rapid scan and 15min for continuous wave. Relative to continuous wave projections obtained for the same data acquisition time, rapid-scan projections had significantly less low-frequency noise and substantially higher signal-to-noise at higher gradients. Because of the improved image quality for the same data acquisition time, linewidths could be determined more accurately from the rapid-scan images than from the continuous wave images.
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Affiliation(s)
- Joshua R Biller
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States; Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States
| | - Mark Tseitlin
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States; Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States
| | - Richard W Quine
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States; School of Engineering and Computer Science, University of Denver, Denver, CO 80208, United States
| | - George A Rinard
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States; School of Engineering and Computer Science, University of Denver, Denver, CO 80208, United States
| | - Hilary A Weismiller
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States; Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States
| | - Hanan Elajaili
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States; Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States
| | - Gerald M Rosen
- Center for Biomedical Engineering and Technology, University of Maryland, School of Medicine, Baltimore, MD 21201, United States; Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201, United States
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, University of Maryland, School of Medicine, Baltimore, MD 21201, United States; Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD 21201, United States
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States; Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States; Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208, United States.
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23
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Biller JR, Elajaili H, Meyer V, Rosen GM, Eaton SS, Eaton GR. Electron spin-lattice relaxation mechanisms of rapidly-tumbling nitroxide radicals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 236:47-56. [PMID: 24056272 PMCID: PMC3952064 DOI: 10.1016/j.jmr.2013.08.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 05/12/2023]
Abstract
Electron spin relaxation times at 295 K were measured at frequencies between 250 MHz and 34 GHz for perdeuterated 2,2,6,6-tetramethyl-4-piperidone-1-oxyl (PDT) in five solvents with viscosities that result in tumbling correlation times, τR, between 4 and 50 ps and for three (14)N/(15)N pairs of nitroxides in water with τR between 9 and 19 ps. To test the impact of structure on relaxation three additional nitroxides with τR between 10 and 26 ps were studied. In this fast tumbling regime T2(-1)~T1(-1) at frequencies up to about 9 GHz. At 34 GHz T2(-1)>T1(-1) due to increased contributions to T2(-1) from incomplete motional averaging of g-anisotropy, and T2(-1)-T1(-1) is proportional to τR. The contribution to T1(-1) from spin rotation is independent of frequency and decreases as τR increases. Spin rotation dominates T1(-1) at 34 GHz for all τR studied, and at all frequencies studied for τR=4 ps. The contribution to T1(-1) from modulation of nitrogen hyperfine anisotropy increases as frequency decreases and as τR increases; it dominates at low frequencies for τR>~15 ps. The contribution from modulation of g anisotropy is significant only at 34 GHz. Inclusion of a thermally-activated process was required to account for the observation that for most of the radicals, T1(-1) was smaller at 250 MHz than at 1-2 GHz. The significant (15)N/(14)N isotope effect, the small H/D isotope effect, and the viscosity dependence of the magnitude of the contribution from the thermally-activated process suggest that it arises from intramolecular motions of the nitroxide ring that modulate the isotropic A values.
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Affiliation(s)
- Joshua R. Biller
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Hanan Elajaili
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Virginia Meyer
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Gerald M. Rosen
- Department of Pharmaceutical Sciences, Center for EPR Imaging in Vivo Physiology, and Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD 21201
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry and Center for EPR Imaging In Vivo Physiology, University of Denver, Denver, CO 80208
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24
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Miyake Y, Wang X, Amasaka M, Itto K, Xu S, Arimoto H, Fujii H, Hirata H. Simultaneous Imaging of an Enantiomer Pair by Electron Paramagnetic Resonance Using Isotopic Nitrogen Labeling. Anal Chem 2012; 85:985-90. [DOI: 10.1021/ac302710m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yusuke Miyake
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
| | - Xiaolei Wang
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Mitsuo Amasaka
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
| | - Kaori Itto
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Shu Xu
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Hirokazu Arimoto
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Hirotada Fujii
- Department
of Arts and Sciences, Center for Medical Education, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo
060-8556, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
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25
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Epel, B, Halpern H. Electron paramagnetic resonance oxygen imaging in vivo. ELECTRON PARAMAGNETIC RESONANCE 2012. [DOI: 10.1039/9781849734837-00180] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This review covers the last 15 years of the development of EPR in vivo oxygen imaging. During this time, a number of major technological and methodological advances have taken place. Narrow line width, long relaxation time, and non-toxic triaryl methyl radicals were introduced in the late 1990s. These not only improved continuous wave (CW) imaging, but also enabled the application of pulse EPR imaging to animals. Recent developments in pulse technology have brought an order of magnitude increase in image acquisition speed, enhancement of sensitivity, and considerable improvement in the precision and accuracy of oxygen measurements. Consequently, pulse methods take up a significant part of this review.
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Affiliation(s)
- Boris Epel,
- Center for EPR Imaging in vivo Physiology the University of Chicago, Department of Radiation and Cellular Oncology (MC 1105), Chicago Illinois 60637
| | - Howard Halpern
- Center for EPR Imaging in vivo Physiology the University of Chicago, Department of Radiation and Cellular Oncology (MC 1105), Chicago Illinois 60637
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26
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Kirschenbaum LJ, Riesz P. Sonochemical degradation of cyclic nitroxides in aqueous solution. ULTRASONICS SONOCHEMISTRY 2012; 19:1114-1119. [PMID: 22361491 DOI: 10.1016/j.ultsonch.2012.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 01/06/2012] [Accepted: 01/28/2012] [Indexed: 05/31/2023]
Abstract
The sonochemical degradation of eight five- and six-membered nitroxides has been studied by EPR spectroscopy after exposure to ultrasound at a frequency of 354 kHz in argon-saturated aqueous solution. Concentration vs. time profiles do not follow a simple rate law. Octanol/water partition functions have been determined for all eight nitroxides, and an excellent linear correlation has been found between initial decomposition rates and hydrophobicity (log K(octanol/water)). Variation of initial rate with concentration was investigated for one compound (TEMPONE) and is largely consistent with an equilibrium distribution of substrate between bulk solution and the gas/liquid interface.
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27
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Bobko AA, Dhimitruka I, Komarov DA, Khramtsov VV. Dual-function pH and oxygen phosphonated trityl probe. Anal Chem 2012; 84:6054-60. [PMID: 22703565 DOI: 10.1021/ac3008994] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Triarylmethyl radicals (TAMs) are used as persistent paramagnetic probes for electron paramagnetic resonance (EPR) spectroscopic and imaging applications and as hyperpolarizing and contrast agents for magnetic resonance imaging (MRI) and proton-electron double-resonance imaging (PEDRI). Recently we proposed the concept of dual-function pH and oxygen TAM probes based on the incorporation of ionizable groups into the TAM structure ( J. Am. Chem. Soc. 2007 , 129 , 7240 - 7241 ). In this paper we report the synthesis of a deuterated derivative of phosphonated trityl radical, pTAM. The presence of phosphono substitutes in the structure of TAM provides pH sensitivity of its EPR spectrum in the physiological range from 6 to 8, the phosphorus hyperfine splitting acting as a convenient and highly sensitive pH marker (spectral sensitivity, 3Δa(P)/ΔpH ≈ 0.5 G/pH unit; accuracy of pH measurements, ±0.05). In addition, substitution of 36 methyl protons with deuterons significantly decreased the individual line width of pTAM down to 40 mG and, as consequence, provided high sensitivity of the line-width broadening to pO(2) (ΔH/ΔpO(2) ≈ 0.4 mG/mmHg; accuracy of pO(2) measurements, ≈1 mmHg). The independent character of pH and [O(2)] effects on the EPR spectra of pTAM provides dual functionality to this probe, allowing extraction of both parameters from a single EPR spectrum.
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Affiliation(s)
- Andrey A Bobko
- Dorothy M. Davis Heart & Lung Research Institute and Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, United States
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28
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Ahmad R, Potter LC, Khramtsov VV. Spectral modeling for accelerated pH spectroscopy using EPR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 218:86-92. [PMID: 22578559 PMCID: PMC3351691 DOI: 10.1016/j.jmr.2012.03.002] [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: 01/12/2012] [Revised: 03/01/2012] [Accepted: 03/02/2012] [Indexed: 05/31/2023]
Abstract
A data modeling and processing method for electron paramagnetic resonance (EPR)-based pH spectroscopy is presented. The proposed method models the EPR spectrum of a pH-sensitive probe in both protonated and unprotonated forms. Under slow-exchange conditions, the EPR spectrum of a sample with an unknown pH value can be accurately represented by a weighted sum of the two models, with the pH value completely determined by their relative weights. Unlike traditional pH spectroscopy, which relies on locating resonance peaks, the proposed modeling-based approach utilizes the information from the entire scan and hence leads to more accurate estimation of pH for a given acquisition time. By employing the proposed methodology, we expect a reduction in the pH estimation error by more than a factor of three, which represents an order of magnitude reduction in acquisition time compared to the traditional method.
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Affiliation(s)
- R Ahmad
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
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29
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Chen Z, Reyes LA, Johnson DH, Velayutham M, Yang C, Samouilov A, Zweier JL. Fast gated EPR imaging of the beating heart: spatiotemporally resolved 3D imaging of free-radical distribution during the cardiac cycle. Magn Reson Med 2012; 69:594-601. [PMID: 22473660 DOI: 10.1002/mrm.24250] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/13/2012] [Accepted: 02/20/2012] [Indexed: 11/06/2022]
Abstract
In vivo or ex vivo electron paramagnetic resonance imaging (EPRI) is a powerful technique for determining the spatial distribution of free radicals and other paramagnetic species in living organs and tissues. However, applications of EPRI have been limited by long projection acquisition times and the consequent fact that rapid gated EPRI was not possible. Hence in vivo EPRI typically provided only time-averaged information. In order to achieve direct gated EPRI, a fast EPR acquisition scheme was developed to decrease EPR projection acquisition time down to 10-20 ms, along with corresponding software and instrumentation to achieve fast gated EPRI of the isolated beating heart with submillimeter spatial resolution in as little as 2-3 min. Reconstructed images display temporal and spatial variations of the free-radical distribution, anatomical structure, and contractile function within the rat heart during the cardiac cycle.
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Affiliation(s)
- Zhiyu Chen
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
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30
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Caia GL, Efimova OV, Velayutham M, El-Mahdy MA, Abdelghany TM, Kesselring E, Petryakov S, Sun Z, Samouilov A, Zweier JL. Organ specific mapping of in vivo redox state in control and cigarette smoke-exposed mice using EPR/NMR co-imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 216:21-7. [PMID: 22296801 PMCID: PMC4073597 DOI: 10.1016/j.jmr.2011.10.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 10/25/2011] [Accepted: 10/25/2011] [Indexed: 05/31/2023]
Abstract
In vivo mapping of alterations in redox status is important for understanding organ specific pathology and disease. While electron paramagnetic resonance imaging (EPRI) enables spatial mapping of free radicals, it does not provide anatomic visualization of the body. Proton MRI is well suited to provide anatomical visualization. We applied EPR/NMR co-imaging instrumentation to map and monitor the redox state of living mice under normal or oxidative stress conditions induced by secondhand cigarette smoke (SHS) exposure. A hybrid co-imaging instrument, EPRI (1.2 GHz)/proton MRI (16.18 MHz), suitable for whole-body co-imaging of mice was utilized with common magnet and gradients along with dual EPR/NMR resonators that enable co-imaging without sample movement. The metabolism of the nitroxide probe, 3-carbamoyl-proxyl (3-CP), was used to map the redox state of control and SHS-exposed mice. Co-imaging allowed precise 3D mapping of radical distribution and reduction in major organs such as the heart, lungs, liver, bladder and kidneys. Reductive metabolism was markedly decreased in SHS-exposed mice and EPR/NMR co-imaging allowed quantitative assessment of this throughout the body. Thus, in vivo EPR/NMR co-imaging enables in vivo organ specific mapping of free radical metabolism and redox stress and the alterations that occur in the pathogenesis of disease.
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Affiliation(s)
- George L. Caia
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Olga V. Efimova
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Murugesan Velayutham
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Mohamed A. El-Mahdy
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Tamer M. Abdelghany
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Eric Kesselring
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Sergey Petryakov
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Ziqi Sun
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Alexandre Samouilov
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Jay L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging and Center for Environmental and Smoking Induced Disease, the Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, the Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
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31
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Elas M, Ichikawa K, Halpern HJ. Oxidative stress imaging in live animals with techniques based on electron paramagnetic resonance. Radiat Res 2012; 177:514-23. [PMID: 22348251 DOI: 10.1667/rr2668.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Oxidative stress has been the object of considerable biological and biochemical investigation. Quantification has been difficult although the quantitative level of products of biological oxidations in tissues and tissue products has emerged as a widely used technique. The relationship between these products and the amount of oxidative stress is less clear. Imaging oxidative stress with electron paramagnetic resonance related magnetic resonance imaging, while not addressing the specific issue of quantification of initiating events, focuses on the anatomic specific location of the oxidative stress. Moreover, the relative quantification of oxidative stress of one location against another is possible, sharpening our understanding of oxidative stress. This promises to improve our understanding of oxidative stress and its deleterious consequences and enhance our understanding of the effectiveness of interventions to modulate oxidative stress and its consequences.
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Affiliation(s)
- Martyna Elas
- Department of Radiation and Cellular Oncology, University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA
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32
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Mitchell DG, Quine RW, Tseitlin M, Eaton SS, Eaton GR. X-band rapid-scan EPR of nitroxyl radicals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 214:221-226. [PMID: 22169156 DOI: 10.1016/j.jmr.2011.11.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 11/09/2011] [Accepted: 11/10/2011] [Indexed: 05/31/2023]
Abstract
X-band rapid-scan EPR spectra were obtained for dilute aqueous solutions of nitroxyl radicals (15)N-mHCTPO (4-hydro-3-carbamoyl-2,2,5,5-tetra-perdeuteromethyl-pyrrolin-1-(15)N-oxyl-d(12)) and (15)N-PDT (4-oxo-2,2,6,6-tetra-perdeuteromethyl-piperidinyl-(15)N-oxyl-d(16)). Simulations of spectra for (15)N-mHCTPO and (15)N-PDT agreed well with the experimental spectra. As the scan rate is increased in the rapid scan regime, the region in which signal amplitude increases linearly with B(1) extends to higher power and the maximum signal amplitude increases. In the rapid scan regime, the signal-to-noise for rapid-scan spectra was about a factor of 2 higher than for unbroadened CW EPR, even when the rapid scan spectra were obtained in a mode that had only 4% duty cycle for data acquisition. Further improvement in signal-to-noise per unit time is expected for higher duty cycles. Rapid scan spectra have higher bandwidth than CW spectra and therefore require higher detection bandwidths at faster scan rates. However, when the scan rate is increased by increasing the scan frequency, the increase in noise from the detection bandwidth is compensated by the decrease in noise due to increased number of averages per unit time. Because of the higher signal bandwidth, lower resonator Q is needed for rapid scan than for CW, so the rapid scan method is advantageous for lossy samples that inherently lower resonator Q.
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Affiliation(s)
- Deborah G Mitchell
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
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33
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Bobko AA, Eubank TD, Voorhees JL, Efimova OV, Kirilyuk IA, Petryakov S, Trofimiov DG, Marsh CB, Zweier JL, Grigor'ev IA, Samouilov A, Khramtsov VV. In vivo monitoring of pH, redox status, and glutathione using L-band EPR for assessment of therapeutic effectiveness in solid tumors. Magn Reson Med 2011; 67:1827-36. [PMID: 22113626 DOI: 10.1002/mrm.23196] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/22/2011] [Accepted: 08/03/2011] [Indexed: 01/27/2023]
Abstract
Approach for in vivo real-time assessment of tumor tissue extracellular pH (pH(e)), redox, and intracellular glutathione based on L-band EPR spectroscopy using dual function pH and redox nitroxide probe and disulfide nitroxide biradical, is described. These parameters were monitored in PyMT mice bearing breast cancer tumors during treatment with granulocyte macrophage colony-stimulating factor. It was observed that tumor pH(e) is about 0.4 pH units lower than that in normal mammary gland tissue. Treatment with granulocyte macrophage colony-stimulating factor decreased the value of pH(e) by 0.3 units compared with PBS control treatment. Tumor tissue reducing capacity and intracellular glutathione were elevated compared with normal mammary gland tissue. Granulocyte macrophage colony-stimulating factor treatment resulted in a decrease of the tumor tissue reducing capacity and intracellular glutathione content. In addition to spectroscopic studies, pH(e) mapping was performed using recently proposed variable frequency proton-electron double-resonance imaging. The pH mapping superimposed with MRI image supports probe localization in mammary gland/tumor tissue, shows high heterogeneity of tumor tissue pH(e) and a difference of about 0.4 pH units between average pH(e) values in tumor and normal mammary gland. In summary, the developed multifunctional approach allows for in vivo, noninvasive pH(e), extracellular redox, and intracellular glutathione content monitoring during investigation of various therapeutic strategies for solid tumors.
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Affiliation(s)
- Andrey A Bobko
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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34
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Davis RM, Mitchell JB, Krishna MC. Nitroxides as cancer imaging agents. Anticancer Agents Med Chem 2011; 11:347-58. [PMID: 21434855 DOI: 10.2174/187152011795677526] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 03/09/2011] [Indexed: 01/13/2023]
Abstract
Nitroxides are low molecular weight (150-400 Da) superoxide dismutase mimics that exhibit antioxidant, radical scavenging, and radioprotective activity. Additionally, the paramagnetic nature of nitroxides makes them viable as both spin probes for electron paramagnetic resonance imaging as well as contrast agents for magnetic resonance imaging. These imaging techniques enable in vivo monitoring of nitroxide metabolism. In biological systems, nitroxide metabolism occurs predominantly via reduction of the nitroxide to a hydroxylamine. The rate of nitroxide reduction can increase or decrease due to either oxidative stress, suggesting that nitroxides can provide an imaging-based assay of tissue redox status. The current review briefly summarizes the potential clinical applications of nitroxides, and focuses on the biochemical and tumor microenvironmental factors that affect the rate of nitroxide reduction. The potential therapeutic applications and bio-reduction mechanisms are discussed in the context of their relevance to oncology.
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Affiliation(s)
- Ryan M Davis
- Radiation Biology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892, USA.
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35
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Yu R, Zhao H, Zhao Z, Wan Y, Yuan H, Lan M, Lindoy LF, Wei G. A pH dependent thermo-sensitive copolymer drug carrier incorporating 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl (4-NH2-TEMPO) residues for electron spin resonance (ESR) labeling. J Colloid Interface Sci 2011; 362:584-93. [DOI: 10.1016/j.jcis.2011.06.079] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 06/23/2011] [Accepted: 06/25/2011] [Indexed: 01/31/2023]
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36
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Shin CS, Dunnam CR, Borbat PP, Dzikovski B, Barth ED, Halpern HJ, Freed JH. ESR Microscopy for Biological and Biomedical Applications. NANOSCIENCE AND NANOTECHNOLOGY LETTERS (PRINT) 2011; 3:561-567. [PMID: 21984955 PMCID: PMC3188420 DOI: 10.1166/nnl.2011.1206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on electron-spin resonance microscopy (ESRM) providing sub-micron resolution (~700nm) with a high spin concentration sample, i.e. lithium phthalocyanine (LiPc) crystal. For biomedical applications of our ESRM, we have imaged samples containing rat basophilic leukemia (RBL) cells as well as cancerous tissue samples with a resolution of several microns using a water soluble spin probe, Trityl_OX063_d24. Phantom samples with the nitroxide spin label, (15)N PDT, were also imaged to demonstrate that nitroxides, which are commonly used as spin labels, may also be used for ESRM applications. ESRM tissue imaging would therefore be valuable for diagnostic or therapeutic purposes. Also, ESRM can be used to study the motility or the metabolism of cells in various environments. With further modification and/or improvement of imaging probe and spectrometer instrumentation sub-micron biological images should be obtainable, thereby providing a useful tool for various biomedical applications.
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Affiliation(s)
- C. S. Shin
- National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, NY 14853, USA
- Dept of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - C. R. Dunnam
- National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, NY 14853, USA
- Dept of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - P. P. Borbat
- National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, NY 14853, USA
- Dept of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - B. Dzikovski
- National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, NY 14853, USA
- Dept of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - E. D. Barth
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637 USA
| | - H. J. Halpern
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637 USA
| | - J. H. Freed
- National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, NY 14853, USA
- Dept of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
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37
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Studying biomolecular complexes with pulsed electron–electron double resonance spectroscopy. Biochem Soc Trans 2011; 39:128-39. [DOI: 10.1042/bst0390128] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The function of biomolecules is intrinsically linked to their structure and the complexes they form during function. Techniques for the determination of structures and dynamics of these nanometre assemblies are therefore important for an understanding on the molecular level. PELDOR (pulsed electron–electron double resonance) is a pulsed EPR method that can be used to reliably and precisely measure distances in the range 1.5–8 nm, to unravel orientations and to determine the number of monomers in complexes. In conjunction with site-directed spin labelling, it can be applied to biomolecules of all sizes in aqueous solutions or membranes. PELDOR is therefore complementary to the methods of X-ray crystallography, NMR and FRET (fluorescence resonance energy transfer) and is becoming a powerful method for structural determination of biomolecules. In the present review, the methods of PELDOR are discussed and examples where PELDOR has been used to obtain structural information on biomolecules are summarized.
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38
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39
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Fujii H, Sato-Akaba H, Kawanishi K, Hirata H. Mapping of redox status in a brain-disease mouse model by three-dimensional EPR imaging. Magn Reson Med 2010; 65:295-303. [DOI: 10.1002/mrm.22598] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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40
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Yasui H, Matsumoto S, Devasahayam N, Munasinghe JP, Choudhuri R, Saito K, Subramanian S, Mitchell JB, Krishna MC. Low-field magnetic resonance imaging to visualize chronic and cycling hypoxia in tumor-bearing mice. Cancer Res 2010; 70:6427-36. [PMID: 20647318 DOI: 10.1158/0008-5472.can-10-1350] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tumors exhibit fluctuations in blood flow that influence oxygen concentrations and therapeutic resistance. To assist therapeutic planning and improve prognosis, noninvasive dynamic imaging of spatial and temporal variations in oxygen partial pressure (pO(2)) would be useful. Here, we illustrate the use of pulsed electron paramagnetic resonance imaging (EPRI) as a novel imaging method to directly monitor fluctuations in oxygen concentrations in mouse models. A common resonator platform for both EPRI and magnetic resonance imaging (MRI) provided pO(2) maps with anatomic guidance and microvessel density. Oxygen images acquired every 3 minutes for a total of 30 minutes in two different tumor types revealed that fluctuation patterns in pO(2) are dependent on tumor size and tumor type. The magnitude of fluctuations in pO(2) in SCCVII tumors ranged between 2- to 18-fold, whereas the fluctuations in HT29 xenografts were of lower magnitude. Alternating breathing cycles with air or carbogen (95% O(2) plus 5% CO(2)) distinguished higher and lower sensitivity regions, which responded to carbogen, corresponding to cycling hypoxia and chronic hypoxia, respectively. Immunohistochemical analysis suggests that the fluctuation in pO(2) correlated with pericyte density rather than vascular density in the tumor. This EPRI technique, combined with MRI, may offer a powerful clinical tool to noninvasively detect variable oxygenation in tumors.
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Affiliation(s)
- Hironobu Yasui
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892-1002, USA
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41
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Guo X, Chang C, Lam EY. Blind separation of electron paramagnetic resonance signals using diversity minimization. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 204:26-36. [PMID: 20194039 DOI: 10.1016/j.jmr.2010.01.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 12/23/2009] [Accepted: 01/29/2010] [Indexed: 05/28/2023]
Abstract
This paper presents a method for the blind separation of Electron Paramagnetic Resonance (EPR) spectroscopy signals that can aid in the detection of free radicals in living organisms. Observed EPR signals are often mixtures of source signals that are approximately "sparse", with a small number of narrow segments of the signal much larger than the remaining parts. We develop a method to separate the sources through minimizing a p-norm-like diversity measure under some mild assumptions which are generally valid for EPR signals. Simulations demonstrate that the proposed method performs well on EPR signal separation, with better robustness to noise compared to other techniques.
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Affiliation(s)
- Xiansheng Guo
- Department of Electrical and Electronic Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, China
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Khramtsov VV, Caia GL, Shet K, Kesselring E, Petryakov S, Zweier JL, Samouilov A. Variable Field Proton-Electron Double-Resonance Imaging: Application to pH mapping of aqueous samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 202:267-273. [PMID: 20007019 PMCID: PMC2818733 DOI: 10.1016/j.jmr.2009.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 08/27/2009] [Accepted: 11/20/2009] [Indexed: 05/28/2023]
Abstract
A new concept of Variable Field Proton-Electron Double-Resonance Imaging (VF PEDRI) is proposed. This allows for functional mapping using specifically designed paramagnetic probes (e.g. oxygen or pH mapping) with MRI high quality spatial resolution and short acquisition time. Studies performed at 200 G field MRI with phantoms show that a pH map of the sample can be extracted using only two PEDRI images acquired in 140 s at pre-selected EPR excitation fields providing pH resolution of 0.1 pH units and a spatial resolution of 1.25mm. Note that while concept of functional VF PEDRI was demonstrated using the pH probe, it can be applied for studies of other biologically relevant parameters of the medium such as redox state, concentrations of oxygen or glutathione using specifically designed EPR probes.
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Affiliation(s)
| | | | | | | | | | | | - Alexandre Samouilov
- Address for correspondence: Alexandre Samouilov, Davis Heart and Lung Research Institute, The Ohio State University, 420 West 12 Ave, Room 611B, Columbus, OH 43210.
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Sato-Akaba H, Kuwahara Y, Fujii H, Hirata H. Half-Life Mapping of Nitroxyl Radicals with Three-Dimensional Electron Paramagnetic Resonance Imaging at an Interval of 3.6 Seconds. Anal Chem 2009; 81:7501-6. [DOI: 10.1021/ac901169g] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hideo Sato-Akaba
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan, and School of Health Sciences, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Yoko Kuwahara
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan, and School of Health Sciences, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hirotada Fujii
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan, and School of Health Sciences, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan, and School of Health Sciences, Sapporo Medical University, Sapporo 060-8556, Japan
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