1
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Yasukawa K. Redox-Based Theranostics of Gastric Ulcers Using Nitroxyl Radicals. Antioxid Redox Signal 2022; 36:160-171. [PMID: 34498915 DOI: 10.1089/ars.2021.0104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Significance: Redox-based theranostics involves redox monitoring and therapeutics that normalize redox imbalance. It may be a promising approach to markedly improve a patient's quality of life through streamlined treatment. Nitroxyl radicals are useful for both redox monitoring and treating gastric ulcers in rodents. Recent Advances: Redox monitoring using in vivo electron paramagnetic resonance (EPR) spectroscopy in a gastric ulcer rat model showed the production of reactive oxygen species in the whole stomach. A combination of Overhauser-enhanced magnetic resonance imaging (MRI) and nitroxyl radicals provided high-resolution images of redox imbalance in the stomach of rats with a gastric ulcer. Treatment with nitroxyl radicals was effective to treat ulcers that were formed using model experiments of Helicobacter pylori and mental stress as well as nonsteroidal anti-inflammatory drugs. Critical Issues: For redox monitoring using Overhauser-enhanced MRI, the EPR irradiation power that is delivered to subjects must be within the range of the specific absorption rate regulation to protect against microwave damage regardless of a decrease in image contrast. The effect of long-term treatment with a nitroxyl radical in patients with a gastric ulcer remains unclear. Future Directions: Further research on redox-based theranostics in redox-related diseases, including gastric ulcers, would be accelerated by improving the redox imager and by developing functional nitroxyl radicals that localize in the target organ, tissue, or cell and that have specific reactivity for the redox-related biomolecule.
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Affiliation(s)
- Keiji Yasukawa
- Laboratory of Advanced Pharmacology, Faculty of Pharmaceutical Sciences, Daiichi University of Pharmacy, Fukuoka, Japan
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2
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Chen L, Wu L, Tan X, Rockenbauer A, Song Y, Liu Y. Synthesis and Redox Properties of Water-Soluble Asymmetric Trityl Radicals. J Org Chem 2021; 86:8351-8364. [PMID: 34043350 DOI: 10.1021/acs.joc.1c00766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tetrathiatriarylmethyl (trityl) radicals have been recently shown to react with biological oxidoreductants including glutathione (GSH), ascorbic acid (Asc), and superoxide anion radical (O2•-). However, how the substituents affect the reactivity of trityl radicals is still unknown. In this work, five asymmetric trityl radicals were synthesized and their reactivities with GSH, Asc, and O2•- investigated. Under aerobic conditions, GSH induces fast decays for the thioether- (TSA) and N-methyleneglycine-substituted (TGA) derivatives and slow decay for the 4-carboxyphenyl-containing one (TPA). Under anaerobic conditions, the direct reduction of these radicals by GSH also occurs with rate constants (kGSH) from 1.8 × 10-4 M-1 s-1 for TPA to 1.0 × 10-2 M-1 s-1 for TGA. Moreover, these radicals can also react with O2•- with rate constants (kSO) from 1.2 × 103 M-1 s-1 for ET-01 to 1.6 × 104 M-1 s-1 for TGA. Surprisingly, these radicals are completely inert to Asc in both aerobic and anaerobic conditions. Additionally, the substituents exert an important effect on redox potentials of these trityl radicals. This work demonstrates that the redox properties of the trityl radicals strongly depend on their substituents, and TPA with high stability toward GSH shows great potential for intracellular applications.
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Affiliation(s)
- Li Chen
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Lanlan Wu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Xiaoli Tan
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary.,Department of Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - Yuguang Song
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
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3
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Matsumoto KI, Mitchell JB, Krishna MC. Multimodal Functional Imaging for Cancer/Tumor Microenvironments Based on MRI, EPRI, and PET. Molecules 2021; 26:1614. [PMID: 33799481 PMCID: PMC8002164 DOI: 10.3390/molecules26061614] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 11/23/2022] Open
Abstract
Radiation therapy is one of the main modalities to treat cancer/tumor. The response to radiation therapy, however, can be influenced by physiological and/or pathological conditions in the target tissues, especially by the low partial oxygen pressure and altered redox status in cancer/tumor tissues. Visualizing such cancer/tumor patho-physiological microenvironment would be a useful not only for planning radiotherapy but also to detect cancer/tumor in an earlier stage. Tumor hypoxia could be sensed by positron emission tomography (PET), electron paramagnetic resonance (EPR) oxygen mapping, and in vivo dynamic nuclear polarization (DNP) MRI. Tissue oxygenation could be visualized on a real-time basis by blood oxygen level dependent (BOLD) and/or tissue oxygen level dependent (TOLD) MRI signal. EPR imaging (EPRI) and/or T1-weighted MRI techniques can visualize tissue redox status non-invasively based on paramagnetic and diamagnetic conversions of nitroxyl radical contrast agent. 13C-DNP MRI can visualize glycometabolism of tumor/cancer tissues. Accurate co-registration of those multimodal images could make mechanisms of drug and/or relation of resulted biological effects clear. A multimodal instrument, such as PET-MRI, may have another possibility to link multiple functions. Functional imaging techniques individually developed to date have been converged on the concept of theranostics.
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Affiliation(s)
- Ken-ichiro Matsumoto
- Quantitative RedOx Sensing Group, Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, Quantum Medical Science Directorate, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - James B. Mitchell
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1002, USA;
| | - Murali C. Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1002, USA;
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4
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Hyodo F, Ito S, Eto H, Elhelaly AE, Murata M, Akahoshi T, Utsumi H, Matuso M. Free radical imaging of endogenous redox molecules using dynamic nuclear polarisation magnetic resonance imaging. Free Radic Res 2020; 55:343-351. [PMID: 33307891 DOI: 10.1080/10715762.2020.1859109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Redox reactions accompanied by the oxidation-reduction of endogenous molecules play important roles in maintaining homeostasis in living organisms. In humans, numerous endogenous molecules that contribute towards maintaining physiological conditions form free radicals via electron transfer. A typical example of this is the mitochondrial electron transport chain, which is involved in energy production. If free radicals derived from endogenous molecules could be visualised and exploited as biological and functional probes, redox reactions mediated by endogenous molecules could be detected non-invasively. We succeeded in visualising the free radicals derived from endogenous molecules using an in vivo dynamic nuclear polarisation (DNP) magnetic resonance imaging (MRI) system. In this review, we describe the visualisation of endogenous redox molecules, such as flavins and ubiquinones, which are mitochondrial electron carriers, as well as vitamin E and vitamin C (ascorbate). In addition, we describe the application of melanin free radicals for the in vivo visualisation of metabola without using probes via in vivo DNP-MRI.
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Affiliation(s)
- Fuminori Hyodo
- Department of Radiology, Frontier Science for Imaging, School of Medicine, Gifu University, Gifu, Japan
| | - Shinji Ito
- Center for Advanced Medical Open Innovation, Kyushu University, Fukuoka, Japan
| | - Hinako Eto
- Center for Advanced Medical Open Innovation, Kyushu University, Fukuoka, Japan
| | - Abdelazim Elsayed Elhelaly
- Department of Radiology, Gifu University, Gifu, Japan.,Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Suez Canal University, Ismalia, Egypt
| | - Masaharu Murata
- Center for Advanced Medical Open Innovation, Kyushu University, Fukuoka, Japan
| | - Tomohiko Akahoshi
- Graduate School of Medicine, Advanced Medical Medicine, Disaster and Emergency medicine, Kyushu University, Fukuoka, Japan
| | - Hideo Utsumi
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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5
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Wang XQ, Wang W, Peng M, Zhang XZ. Free radicals for cancer theranostics. Biomaterials 2020; 266:120474. [PMID: 33125969 DOI: 10.1016/j.biomaterials.2020.120474] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 09/20/2020] [Accepted: 10/18/2020] [Indexed: 01/06/2023]
Abstract
Free radicals were generally regarded as highly reactive, transient and harmful species. In fact, some of the free radicals can also be inactive, long-lived and beneficial for our health. These properties of free radicals provide future possibilities for their application in various fields. Owning to their open-shell electronic structure, free radicals exhibit unique advantages in biomedical applications, such as high reactivity, photoacoustic and photothermal conversion ability, molecular magnetic. In this review, recent progress on free radicals and their applications in cancer theranostics are presented. Typical materials that exhibit controlled generation of free radicals and their applications for photodynamic therapy (PDT), chemodynamic therapy (CDT), sonodynamic therapy (SDT), gas therapy, hypoxic cancer treatment, photothermal therapy (PTT), photoacoustic imaging (PAI) and magnetic resonance imaging (MRI) are summarized and discussed.
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Affiliation(s)
- Xiao-Qiang Wang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, PR China; The State Key Laboratory of Refractories and Metallurgy, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan, 430081, PR China
| | - Wenjing Wang
- The State Key Laboratory of Refractories and Metallurgy, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan, 430081, PR China
| | - Mengyun Peng
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, PR China; School of Pharmacy, Zhejiang Chinese Medical University, Hangzhou, 310000, PR China
| | - Xian-Zheng Zhang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, PR China.
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6
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Wang X, Peng C, He K, Ji K, Tan X, Han G, Liu Y, Liu Y, Song Y. Intracellular delivery of liposome-encapsulated Finland trityl radicals for EPR oximetry. Analyst 2020; 145:4964-4971. [PMID: 32510063 DOI: 10.1039/d0an00108b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tetrathiatriarylmethyl (TAM, trityl) radicals have found wide applications in electron paramagnetic resonance (EPR) oximetry. However, the biomedical applications of TAM radicals were exclusively limited to an extracellular region owing to their negatively charged nature. The intracellular delivery of TAM radicals still remains a challenge. In the present work, we report a liposome-based method to encapsulate the water-soluble Finland trityl radical CT-03 for its intracellular delivery. Using the thin lipid film hydration method, CT-03-loaded liposomes were prepared from DSPC/cholesterol/DOTAP with a mean size of 167.5 ± 2.4 nm and a zeta potential of 27.8 ± 0.8 mV. EPR results showed that CT-03 was entrapped into the liposomes and still exhibited good oxygen (O2) sensitivity. Moreover, CT-03 was successfully delivered into HepG2 cells and HUVECs using the CT-03-loaded liposomes. Importantly, the combination of the liposome-encapsulated radical CT-03 and the other TAM radical CT02-H enabled simultaneous measurements of the intracellular and extracellular O2 concentrations and O2 consumption rates in HepG2 cells. Our present study provides a new approach for intracellular delivery of TAM radicals and could significantly expand their biomedical applications.
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Affiliation(s)
- Xing Wang
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China.
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7
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Merging Preclinical EPR Tomography with other Imaging Techniques. Cell Biochem Biophys 2019; 77:187-196. [PMID: 31440878 PMCID: PMC6742609 DOI: 10.1007/s12013-019-00880-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/30/2019] [Indexed: 12/21/2022]
Abstract
This paper presents a survey of electron paramagnetic resonance (EPR) image registration. Image registration is the process of overlaying images (two or more) of the same scene taken at different times, from different viewpoints and/or different techniques. EPR-imaging (EPRI) techniques belong to the functional-imaging modalities and therefore suffer from a lack of anatomical reference which is mandatory in preclinical imaging. For this reason, it is necessary to merging EPR images with other modalities which allow for obtaining anatomy images. Methodological analysis and review of the literature were done, providing a summary for developing a good foundation for research study in this field which is crucial in understanding the existing levels of knowledge. Out of these considerations, the aim of this paper is to enhance the scientific community’s understanding of the current status of research in EPR preclinical image registration and also communicate to them the contribution of this research in the field of image processing.
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8
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Li C, Huang Z, Gao N, Zheng J, Guan J. Injectable, thermosensitive, fast gelation, bioeliminable, and oxygen sensitive hydrogels. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 99:1191-1198. [PMID: 30889653 PMCID: PMC7368179 DOI: 10.1016/j.msec.2019.02.075] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/06/2019] [Accepted: 02/20/2019] [Indexed: 01/09/2023]
Abstract
The decrease of tissue oxygen content due to pathological conditions leads to severe cell death and tissue damage. Restoration of tissue oxygen content is the primary treatment goal. To accurately and efficiently assess efficacy of a treatment, minimally invasive, and long-term detection of oxygen concentration in the same tissue location represents a clinically attractive strategy. Among the different oxygen concentration measurement approaches, electron paramagnetic resonance (EPR) has the potential to accomplish this. Yet there lacks injectable EPR probes that can maintain a consistent concentration at the same tissue location during treatment period to acquire a stable EPR signal, and can finally be eliminated from body without retrieval. Herein, we developed injectable and bioeliminable hydrogel-based polymeric EPR probes that exhibited fast gelation rate, slow weight loss rate, and high oxygen sensitivity. The probe was based on N-Isopropylacrylamide (NIPAAm), 2-hydroxyethyl methacrylate (HEMA), dimethyl-γ-butyrolactone acrylate (DBA), and tetrathiatriarylmethyl (TAM) radical. The injectable probes can be implanted into tissues using a minimally invasive injection approach. The high gelation rate (~10 s) allowed the probes to quickly solidify upon injection to have a high retention in tissues. The polymeric probes overcame the toxicity issue of current small molecule EPR probes. The probes can be gradually hydrolyzed. Upon complete hydrolysis, the probes became water soluble at 37 °C, thus having the potential to be removed from the body by urinary system. The probes showed slow weight loss rate so as to maintain EPR signal intensity for extended periods while retaining in a certain tissue location. The probes remained their high oxygen sensitivity after in vitro hydrolysis and in vivo implantation for 4 weeks. These hydrogel-based EPR probes have attractive properties for in vivo oxygen detection.
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Affiliation(s)
- Chao Li
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Zheng Huang
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Ning Gao
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA; Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Jie Zheng
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Jianjun Guan
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA; Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA.
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9
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Yasukawa K, Shigemi R, Kanbe T, Mutsumoto Y, Oda F, Ichikawa K, Yamada KI, Tun X, Utsumi H. In Vivo Imaging of the Intra- and Extracellular Redox Status in Rat Stomach with Indomethacin-Induced Gastric Ulcers Using Overhauser-Enhanced Magnetic Resonance Imaging. Antioxid Redox Signal 2019; 30:1147-1161. [PMID: 29631421 DOI: 10.1089/ars.2017.7336] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AIMS Repeated use of nonsteroidal anti-inflammatory drugs can induce changes in the redox status, including production of reactive oxygen species (ROS), but the specific details of these changes remain unknown. Overhauser-enhanced magnetic resonance imaging (OMRI) has been used in vivo to monitor the redox status in several diseases and map tissue oxygen concentrations. We monitored the intra- and extracellular redox status in the stomach of rats with indomethacin-induced gastric ulcers using OMRI and investigated the relationship with gastric mucosal damage. RESULTS One hour after oral administration of indomethacin (30 mg/kg), OMRI measurements in the stomach were made following nitroxyl probe administration. OMRI with the membrane-permeable nitroxyl probe, 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPOL), demonstrated a redox change toward oxidation, which was reversed by a membrane-permeable antioxidant. Conversely, imaging with the impermeable probe, 4-trimethylammonium-2,2,6,6-tetramethyl-piperidine-1-oxyl (CAT-1), demonstrated little redox change. Redox imbalance imaging of a live rat stomach with indomethacin-induced gastric ulcers was produced by dual imaging of 15N-labeled TEMPOL and 14N-labeled CAT-1, in addition to imaging with another membrane-permeable 15N-labeled probe, 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl (MC-PROXYL), and 14N-labeled CAT-1. Pretreatment with MC-PROXYL suppressed gastric mucosal damage, whereas pretreatment with CAT-1 did not suppress ulcer formation. INNOVATION OMRI combined with a dual probe is a less invasive imaging technique for evaluation of intracellular ROS production contributing to the formation of gastric ulcers in the stomach of indomethacin-treated rats, which cannot be done with other methods. CONCLUSION This method may be a very powerful tool for characterizing the pathogenesis of various diseases and may have medical applications.
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Affiliation(s)
- Keiji Yasukawa
- 1 Laboratory of Advanced Pharmacology, Daiichi University of Pharmacy, Fukuoka, Japan.,2 Physical Chemistry for Life Science Laboratory, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,3 Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan
| | - Ryota Shigemi
- 2 Physical Chemistry for Life Science Laboratory, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomomi Kanbe
- 2 Physical Chemistry for Life Science Laboratory, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yusaku Mutsumoto
- 2 Physical Chemistry for Life Science Laboratory, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Fumiko Oda
- 2 Physical Chemistry for Life Science Laboratory, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhiro Ichikawa
- 3 Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan
| | - Ken-Ichi Yamada
- 2 Physical Chemistry for Life Science Laboratory, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Xin Tun
- 4 Division of Host Defense, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Hideo Utsumi
- 5 School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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10
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Tan X, Chen L, Song Y, Rockenbauer A, Villamena FA, Zweier JL, Liu Y. Thiol-Dependent Reduction of the Triester and Triamide Derivatives of Finland Trityl Radical Triggers O2-Dependent Superoxide Production. Chem Res Toxicol 2017; 30:1664-1672. [DOI: 10.1021/acs.chemrestox.7b00086] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Xiaoli Tan
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Li Chen
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Yuguang Song
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Antal Rockenbauer
- Institute
of Materials and Environmental Chemistry, Hungarian Academy of Sciences,
Department of Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - Frederick A. Villamena
- Department
of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Jay L. Zweier
- Center
for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung
Research Institute, The Division of Cardiovascular Medicine, Department
of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yangping Liu
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
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11
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Liu W, Nie J, Tan X, Liu H, Yu N, Han G, Zhu Y, Villamena FA, Song Y, Zweier JL, Liu Y. Synthesis and Characterization of PEGylated Trityl Radicals: Effect of PEGylation on Physicochemical Properties. J Org Chem 2016; 82:588-596. [DOI: 10.1021/acs.joc.6b02590] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Wenbo Liu
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Jiangping Nie
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Xiaoli Tan
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Huiqiang Liu
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Nannan Yu
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Guifang Han
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Yutian Zhu
- State
Key
Laboratory of Polymer Physics and Chemistry, Changchun Institute of
Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Frederick A. Villamena
- Department
of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yuguang Song
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Jay L. Zweier
- Center
for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung
Research Institute, the Division of Cardiovascular Medicine, Department
of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yangping Liu
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
- Center
for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung
Research Institute, the Division of Cardiovascular Medicine, Department
of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, United States
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12
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Meenakumari V, Utsumi H, Jawahar A, Milton Franklin Benial A. ESR line width and line shape dependence of Overhauser-enhanced magnetic resonance imaging. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:874-879. [PMID: 27432403 DOI: 10.1002/mrc.4489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 07/10/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
Electron spin resonance and Overhauser-enhanced magnetic resonance imaging studies were carried out for various concentrations of 14 N-labeled 3-carbamoyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl in pure water. Overhauser-enhancement factor attains maxima in the range of 2.5-3 mm concentration. The leakage factor showed an asymptotic increase with increasing agent concentration. The coupling parameter showed the interaction between the electron and nuclear spins to be mainly dipolar in origin. The electron spin resonance parameters, such as the line width, line shape and g-factor, were determined. The line width analysis confirms that the line broadening is proportional to the agent concentration, and also the agent concentration is optimized in the range of 2.5-3 mm. The line shape analysis shows that the observed electron spin resonance line shape is a Voigt line shape, in which the Lorentzian component is dominant. The contribution of Lorentzian component was estimated using the winsim package. The Lorentzian component of the resonance line attains maxima in the range of 2.5-3 mm concentration. Therefore, this study reveals that the agent concentration, line width and Lorentzian component are the important factors in determining the Overhauser-enhancement factor. Hence, the agent concentration was optimized as 2.5-3 mm for in vivo/in vitro electron spin resonance imaging and Overhauser-enhanced magnetic resonance imaging phantom studies. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- V Meenakumari
- Department of Physics, NMSSVN College, Madurai, Tamil Nadu, India
| | - Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan
| | - A Jawahar
- Department of Chemistry, NMSSVN College, Madurai, Tamil Nadu, India
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13
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Dhimitruka I, Alzarie YA, Hemann C, Samouilov A, Zweier JL. Trityl radicals in perfluorocarbon emulsions as stable, sensitive, and biocompatible oximetry probes. Bioorg Med Chem Lett 2016; 26:5685-5688. [PMID: 27836400 DOI: 10.1016/j.bmcl.2016.10.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 10/20/2022]
Abstract
EPR oximetry with the use of trityl radicals can enable sensitive O2 measurement in biological cells and tissues. However, in vitro cellular and in vivo biological applications are limited by rapid trityl probe degradation or biological clearance and the need to enhance probe O2 sensitivity. We synthesized novel perfluorocarbon (PFC) emulsions, ∼200nm droplet size, containing esterified perchlorinated triphenyl methyl (PTM) radicals dispersed in physiological aqueous buffers. These formulations exhibit excellent EPR signal stability, over 20-fold greater than free PTM probes, with high oxygen sensitivity ∼17mG/mmHg enabling pO2 measurement in aqueous solutions or cell suspensions with sensitivity >0.5mmHg. Thus, PFC-PTM probes hold great promise to enable combined O2 delivery and sensing as needed to restore or enhance tissue oxygenation in disease.
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Affiliation(s)
- Ilirian Dhimitruka
- Department of Internal Medicine, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Yasmin Alsayed Alzarie
- Department of Internal Medicine, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Craig Hemann
- Department of Internal Medicine, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Alexandre Samouilov
- Department of Internal Medicine, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Jay L Zweier
- Department of Internal Medicine, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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14
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Eto H, Hyodo F, Nakano K, Utsumi H. Selective Imaging of Malignant Ascites in a Mouse Model of Peritoneal Metastasis Using in Vivo Dynamic Nuclear Polarization-Magnetic Resonance Imaging. Anal Chem 2016; 88:2021-7. [PMID: 26796949 DOI: 10.1021/acs.analchem.5b04821] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The presence of malignant ascites in advanced cancer patients is associated with both a poor prognosis and quality of life with a risk of abdominal infection and sepsis. Contemporary noninvasive visualization methods such as ultrasound, computed tomography, and magnetic resonance imaging (MRI) often struggle to differentiate malignant ascites from surrounding tissues. This study aimed to determine the utility of selective H2O imaging in the abdominal cavity with a free radical probe and deuterium oxide (D2O) contrast agent using in vivo dynamic nuclear polarization-MRI (DNP-MRI). Phantom imaging experiments established a linear relationship between H2O volume and image intensity using in vivo DNP-MRI. Similar results were obtained when the radical-D2O probe was used to determine selective and spatial information on H2O in vivo, modeled by the injection of saline into the abdominal cavity of mice. To demonstrate the utility of this method for disease, malignant ascites in peritoneal metastasis animal model was selected as one of the typical examples. In vivo DNP-MRI of peritoneal metastasis animal model was performed 7-21 days after intraperitoneal injection of luciferase, stably expressing the human pancreatic carcinoma (SUIT-2). The image intensity with increasing malignant ascites was significantly increased at days 7, 16, and 21. This increase corresponded to in vivo tumor progression, as measured by bioluminescent imaging. These results suggest that H2O signal enhancement in DNP-MRI using radical-D2O contrast is positively associated with the progression of dissemination and could be a useful biomarker for malignant ascites with cancer metastasis.
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Affiliation(s)
- Hinako Eto
- Innovation Center for Medical Redox Navigation, Kyushu University , 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Fuminori Hyodo
- Innovation Center for Medical Redox Navigation, Kyushu University , 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kenji Nakano
- Innovation Center for Medical Redox Navigation, Kyushu University , 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University , 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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15
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Kumara Dhas M, Utsumi H, Jawahar A, Milton Franklin Benial A. Dynamic nuclear polarization properties of nitroxyl radical in high viscous liquid using Overhauser-enhanced Magnetic Resonance Imaging (OMRI). JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 257:32-38. [PMID: 26047309 DOI: 10.1016/j.jmr.2015.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 06/04/2023]
Abstract
The dynamic nuclear polarization (DNP) studies were carried out for (15)N labeled carbamoyl-PROXYL in pure water and pure water/glycerol mixtures of different viscosities (1.8cP, 7cP and 14cP). The dependence of DNP parameters was demonstrated over a range of agent concentration, viscosities, RF power levels and ESR irradiation time. DNP spectra were also recorded for 2mM concentration of (15)N labeled carbamoyl-PROXYL in pure water and pure water/glycerol mixtures of different viscosities. The DNP factors were measured as a function of ESR irradiation time, which increases linearly up to 2mM agent concentration in pure water and pure water/glycerol mixtures of different viscosities. The DNP factor started declining in the higher concentration region (∼3mM), which is due to the ESR line width broadening. The water proton spin-lattice relaxation time was measured at very low Zeeman field (14.529mT). The increased DNP factor (35%) was observed for solvent 2 (η=1.8cP) compared with solvent 1 (η=1cP). The increase in the DNP factor was brought about by the shortening of water proton spin-lattice relaxation time of solvent 2. The decreased DNP factors (30% and 53%) were observed for solvent 3 (η=7cP) and solvent 4 (η=14cP) compared with solvent 2, which is mainly due to the low value of coupling parameter in high viscous liquid samples. The longitudinal relaxivity, leakage factor and coupling parameter were estimated. The coupling parameter values reveal that the dipolar interaction as the major mechanism. The longitudinal relaxivity increases with the increasing viscosity of pure water/glycerol mixtures. The leakage factor showed an asymptotic increase with the increasing agent concentration. It is envisaged that the results reported here may provide guidelines for the design of new viscosity prone nitroxyl radicals, suited to the biological applications of DNP.
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Affiliation(s)
- M Kumara Dhas
- Department of Physics, NMSSVN College, Nagamalai, Madurai 625 019, Tamil Nadu, India
| | - Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka 812-8582, Japan
| | - A Jawahar
- Department of Chemistry, NMSSVN College, Nagamalai, Madurai 625 019, Tamil Nadu, India
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16
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Affiliation(s)
- Fuminori Hyodo
- Innovation Center for Medical Redox Navigation, Kyushu University
| | - Shinji Ito
- Innovation Center for Medical Redox Navigation, Kyushu University
| | - Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University
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17
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Utsumi H, Hyodo F. Free Radical Imaging Using In Vivo Dynamic Nuclear Polarization-MRI. Methods Enzymol 2015; 564:553-71. [DOI: 10.1016/bs.mie.2015.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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18
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Danhier P, Gallez B. Electron paramagnetic resonance: a powerful tool to support magnetic resonance imaging research. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 10:266-81. [PMID: 25362845 DOI: 10.1002/cmmi.1630] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/18/2014] [Indexed: 12/31/2022]
Abstract
The purpose of this paper is to describe some of the areas where electron paramagnetic resonance (EPR) has provided unique information to MRI developments. The field of application mainly encompasses the EPR characterization of MRI paramagnetic contrast agents (gadolinium and manganese chelates, nitroxides) and superparamagnetic agents (iron oxide particles). The combined use of MRI and EPR has also been used to qualify or disqualify sources of contrast in MRI. Illustrative examples are presented with attempts to qualify oxygen sensitive contrast (i.e. T1 - and T2 *-based methods), redox status or melanin content in tissues. Other areas are likely to benefit from the combined EPR/MRI approach, namely cell tracking studies. Finally, the combination of EPR and MRI studies on the same models provides invaluable data regarding tissue oxygenation, hemodynamics and energetics. Our description will be illustrative rather than exhaustive to give to the readers a flavour of 'what EPR can do for MRI'.
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Affiliation(s)
- Pierre Danhier
- Biomedical Magnetic Resonance Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Bernard Gallez
- Biomedical Magnetic Resonance Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
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19
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Hyodo F, Ito S, Yasukawa K, Kobayashi R, Utsumi H. Simultaneous and spectroscopic redox molecular imaging of multiple free radical intermediates using dynamic nuclear polarization-magnetic resonance imaging. Anal Chem 2014; 86:7234-8. [PMID: 25036767 DOI: 10.1021/ac502150x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Redox reactions that generate free radical intermediates are essential to metabolic processes. However, their intermediates can produce reactive oxygen species, which may promote diseases related to oxidative stress. We report here the use of dynamic nuclear polarization-magnetic resonance imaging (DNP-MRI) to conduct redox molecular imaging. Using DNP-MRI, we obtained simultaneous images of free radical intermediates generated from the coenzyme Q10 (CoQ10), flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD) involved in the mitochondrial electron transport chain as well as the radicals derived from vitamins E and K1. Each of these free radicals was imaged in real time in a phantom comprising a mixture of free radicals localized in either lipophilic or aqueous environments. Changing the frequency of electron spin resonance (ESR) irradiation also allowed each of the radical species to be distinguished in the spectroscopic images. This study is the first to report the spectroscopic DNP-MRI imaging of free radical intermediates that are derived from endogenous species involved in metabolic processes.
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Affiliation(s)
- Fuminori Hyodo
- Innovation Center for Medical Redox Navigation, Kyushu University , 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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20
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Koonjoo N, Parzy E, Massot P, Lepetit-Coiffé M, Marque SRA, Franconi JM, Thiaudiere E, Mellet P. In vivo Overhauser-enhanced MRI of proteolytic activity. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 9:363-71. [PMID: 24729587 DOI: 10.1002/cmmi.1586] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/21/2013] [Accepted: 10/31/2013] [Indexed: 01/22/2023]
Abstract
There is an increasing interest in developing novel imaging strategies for sensing proteolytic activities in intact organisms in vivo. Overhauser-enhanced MRI (OMRI) offers the possibility to reveal the proteolysis of nitroxide-labeled macromolecules thanks to a sharp decrease of the rotational correlation time of the nitroxide moiety upon cleavage. In this paper, this concept is illustrated in vivo at 0.2 T using nitroxide-labeled elastin orally administered in mice. In vitro, this elastin derivative was OMRI-visible and gave rise to high Overhauser enhancements (19-fold at 18 mm nitroxide) upon proteolysis by pancreatic porcine elastase. In vivo three-dimensional OMRI detection of proteolysis was carried out. A keyhole fully balanced steady-state free precession sequence was used, which allowed 3D OMRI acquisition within 20 s at 0.125 mm(3) resolution. About 30 min after mouse gavage, proteolysis was detected in the duodenum, where Overhauser enhancements were 7.2 ± 2.4 (n = 7) and was not observed in the stomach. Conversely, orally administered free nitroxides or pre-digested nitroxide-labeled elastin were detected in the mouse's stomach by OMRI. Combined with specific molecular probes, this Overhauser-enhanced MRI technique can be used to evaluate unregulated proteolytic activities in various models of experimental diseases and for drug testing.
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Affiliation(s)
- Neha Koonjoo
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS Université Bordeaux Segalen, Bordeaux, France
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21
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Utsumi H. Novel Redox Molecular Imaging “ReMI” with Dual Magnetic Resonance. YAKUGAKU ZASSHI 2013; 133:803-14. [DOI: 10.1248/yakushi.13-00139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University
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22
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Massot P, Parzy E, Pourtau L, Mellet P, Madelin G, Marque S, Franconi JM, Thiaudiere E. In vivo high-resolution 3D overhauser-enhanced MRI in mice at 0.2 T. CONTRAST MEDIA & MOLECULAR IMAGING 2012; 7:45-50. [PMID: 22344879 DOI: 10.1002/cmmi.464] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Overhauser-enhanced MRI (OMRI) offers the potentiality of detecting low-concentrated species generated by specific biological processes. However molecular imaging applications of OMRI need significant improvement in spatial localization. Here it is shown that 3D-OMRI of a free radical injected in tumor-bearing mice can be performed at high anatomical resolution at a constant field. A 30 mm cavity operating at 5.43 GHz was inserted in a C-shaped magnet for proton MRI at 0.194 T. Nude mice with or without brain-implanted C6 rat glioma were positioned in the cavity and injected with TOPCA (1-oxyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrole-3-carboxylic acid). OMRI was performed in 3D within several minutes in the brain region without high overheating of the animals. Voxel size was 0.5 × 0.5 × 1 mm³ , providing good delineation of brain regions. Signal amplifications ranged from 2 in tumors to 10 in vessels several minutes after TOPCA injection. Time-course of signal enhancement could be measured by 2D OMRI at 15 s time intervals in a localized thin slice. The method opens the way for molecular imaging of biological activities able to generate OMRI-visible free radicals.
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23
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Sun Z, Li H, Petryakov S, Samouilov A, Zweier JL. In vivo proton electron double resonance imaging of mice with fast spin echo pulse sequence. J Magn Reson Imaging 2011; 35:471-5. [PMID: 22147559 DOI: 10.1002/jmri.22874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 10/05/2011] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To develop and evaluate a two-dimensional (2D) fast spin echo (FSE) pulse sequence for enhancing temporal resolution and reducing tissue heating for in vivo proton electron double resonance imaging (PEDRI) of mice. MATERIALS AND METHODS A four-compartment phantom containing 2 mM TEMPONE was imaged at 20.1 mT using 2D FSE-PEDRI and regular gradient echo (GRE)-PEDRI pulse sequences. Control mice were infused with TEMPONE over ~1 min followed by time-course imaging using the 2D FSE-PEDRI sequence at intervals of 10-30 s between image acquisitions. The average signal intensity from the time-course images was analyzed using a first-order kinetics model. RESULTS Phantom experiments demonstrated that EPR power deposition can be greatly reduced using the FSE-PEDRI pulse sequence compared with the conventional gradient echo pulse sequence. High temporal resolution was achieved at ~4 s per image acquisition using the FSE-PEDRI sequence with a good image SNR in the range of 233-266 in the phantom study. The TEMPONE half-life measured in vivo was ~72 s. CONCLUSION Thus, the FSE-PEDRI pulse sequence enables fast in vivo functional imaging of free radical probes in small animals greatly reducing EPR irradiation time with decreased power deposition and provides increased temporal resolution.
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Affiliation(s)
- Ziqi Sun
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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24
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Efimova OV, Caia GL, Sun Z, Petryakov S, Kesselring E, Samouilov A, Zweier JL. Standard-based method for proton-electron double resonance imaging of oxygen. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 212:197-203. [PMID: 21807539 PMCID: PMC3235921 DOI: 10.1016/j.jmr.2011.06.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/24/2011] [Accepted: 06/28/2011] [Indexed: 05/31/2023]
Abstract
Proton-electron double resonance imaging (PEDRI) has been utilized for indirect determination of oxygen concentrations in aqueous samples and living systems. Due to the complexity of the problem, there are seven oxygen related parameters that need to be measured to determine the distribution of oxygen. We present an improved approach in which image intensities from only two PEDRI acquisitions with different EPR irradiation powers are required to determine the distribution of a paramagnetic probe and oxygen in an analyzed sample. This is achieved using three reference samples with known concentrations of a paramagnetic probe and oxygen placed inside the resonator together with the measurement sample. An EPR-off image, which has low signal intensity at low magnetic field (0.02 T) is not required for the calculations, significantly reducing the total time of the experiments and the noise while enhancing the accuracy of these oxygen measurements. The Finland trityl radical was used as the paramagnetic probe and oxygen concentrations could be accurately measured and imaged over the physiological range from 0 to 240 μM.
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Affiliation(s)
| | | | | | | | | | | | - Jay L. Zweier
- Corresponding author Dr. Jay L. Zweier, The Ohio State University, 473 W. 12 Avenue, Room 611C, Columbus, Ohio 43210, Phone 614-247-7788, Fax 614-247-7845,
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25
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Efimova OV, Sun Z, Petryakov S, Kesselring E, Caia GL, Johnson D, Zweier JL, Khramtsov VV, Samouilov A. Variable radio frequency proton-electron double-resonance imaging: application to pH mapping of aqueous samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 209:227-232. [PMID: 21320790 PMCID: PMC3065501 DOI: 10.1016/j.jmr.2011.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 12/08/2010] [Accepted: 01/10/2011] [Indexed: 05/30/2023]
Abstract
Proton-electron double-resonance imaging (PEDRI) offers rapid image data collection and high resolution for spatial distribution of paramagnetic probes. Recently we developed the concept of variable field (VF) PEDRI which enables extracting a functional map from a limited number of images acquired at pre-selected EPR excitation fields using specific paramagnetic probes (Khramtsov et al., J. Magn. Reson. 202 (2010) 267-273). In this work, we propose and evaluate a new modality of PEDRI-based functional imaging with enhanced temporal resolution which we term variable radio frequency (VRF) PEDRI. The approach allows for functional mapping (e.g., pH mapping) using specifically designed paramagnetic probes with high quality spatial resolution and short acquisition times. This approach uses a stationary magnetic field but different EPR RFs. The ratio of Overhauser enhancements measured at each pixel at two different excitation frequencies corresponding to the resonances of protonated and deprotonated forms of a pH-sensitive nitroxide is converted to a pH map using a corresponding calibration curve. Elimination of field cycling decreased the acquisition time by exclusion periods of ramping and stabilization of the magnetic field. Improved magnetic field homogeneity and stability allowed for the fast MRI acquisition modalities such as fast spin echo. In total, about 30-fold decrease in EPR irradiation time was achieved for VRF PEDRI (2.4s) compared with VF PEDRI (70s). This is particularly important for in vivo applications enabling one to overcome the limiting stability of paramagnetic probes and sample overheating by reducing RF power deposition.
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Affiliation(s)
| | | | | | | | | | | | | | - Valery V. Khramtsov
- Corresponding authors: (Alexandre Samouilov); (Valery V. Khramtsov), Primary address for the correspondence during review process: Alexandre Samouilov, PhD, Davis Heart and Lung Research Institute, The Ohio State University, 420 West 12 Ave, Room 611B, Columbus, OH 43210
| | - Alexandre Samouilov
- Corresponding authors: (Alexandre Samouilov); (Valery V. Khramtsov), Primary address for the correspondence during review process: Alexandre Samouilov, PhD, Davis Heart and Lung Research Institute, The Ohio State University, 420 West 12 Ave, Room 611B, Columbus, OH 43210
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26
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Liu Y, Villamena FA, Song Y, Sun J, Rockenbauer A, Zweier JL. Synthesis of 14N- and 15N-labeled trityl-nitroxide biradicals with strong spin-spin interaction and improved sensitivity to redox status and oxygen. J Org Chem 2010; 75:7796-802. [PMID: 21028905 DOI: 10.1021/jo1016844] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Simultaneous evaluation of redox status and oxygenation in biological systems is of great importance for the understanding of biological functions. Electron paramagnetic resonance (EPR) spectroscopy coupled with the use of the nitroxide radicals have been an indispensable technique for this application but are still limited by low oxygen sensitivity and low EPR resolution in part due to the moderately broad EPR triplet and spin quenching through bioreduction. In this study, we showed that these drawbacks can be overcome through the use of trityl-nitroxide biradicals allowing for the simultaneous measurement of redox status and oxygenation. A new trityl-nitroxide biradical TNN14 composed of a pyrrolidinyl-nitroxide and a trityl and its isotopically labeled (15)N analogue TNN15 were synthesized and characterized. Both biradicals exhibited much stronger spin-spin interaction with J > 400 G compared with that of the previous synthesized trityl-nitroxide biradicals TN1 (∼160 G) and TN2 (∼52 G) with longer linker chain length. The enhanced stability of TNN14 was evaluated using ascorbate as reductant, and the effect of different types of cyclodextrins on its stability in the presence of ascorbate was also investigated. Both biradicals are sensitive to redox status, and their corresponding trityl-hydroxylamines resulting from the reduction of the biradicals by ascorbate share the same oxygen sensitivity. Of note is that the (15)N-labeled TNN15-H with an EPR doublet exhibits improved EPR signal amplitude as compared with that of TNN14-H with an EPR triplet. In addition, cyclic voltammetric studies verify the characteristic electrochemical behaviors of the trityl-nitroxide biradicals.
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Affiliation(s)
- Yangping Liu
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, the Division of Cardiovascular Medicine, Department of Internal Medicine
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27
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Shet K, Caia GL, Kesselring E, Samouilov A, Petryakov S, Lurie DJ, Zweier JL. A novel variable field system for field-cycled dynamic nuclear polarization spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 205:202-208. [PMID: 20570197 PMCID: PMC4073606 DOI: 10.1016/j.jmr.2010.04.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 04/26/2010] [Accepted: 04/26/2010] [Indexed: 05/29/2023]
Abstract
Dynamic nuclear polarization (DNP) is an NMR-based technique which enables detection and spectral characterization of endogenous and exogenous paramagnetic substances measured via transfer of polarization from the saturated unpaired electron spin system to the NMR active nuclei. A variable field system capable of performing DNP spectroscopy with NMR detection at any magnetic field in the range 0-0.38 T is described. The system is built around a clinical open-MRI system. To obtain EPR spectra via DNP, partial cancellation of the detection field B(0)(NMR) is required to alter the evolution field B(0)(EPR) at which the EPR excitation is achieved. The addition of resistive actively shielded field cancellation coils in the gap of the primary magnet provides this field offset in the range of 0-100 mT. A description of the primary magnet, cancellation coils, power supplies, interfacing hardware, RF electronics and console are included. Performance of the instrument has been evaluated by acquiring DNP spectra of phantoms with aqueous nitroxide solutions (TEMPOL) at three NMR detection fields of 97 G, 200 G and 587 G corresponding to 413 kHz, 851.6 kHz and 2.5 MHz respectively and fixed EPR evolution field of 100 G corresponding to an irradiation frequency of 282.3 MHz. This variable-field DNP system offers great flexibility for the performance of DNP spectroscopy with independent optimum choice of EPR excitation and NMR detection fields.
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Affiliation(s)
- Keerthi Shet
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
| | - George L. Caia
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
| | - Eric Kesselring
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
| | - Alexandre Samouilov
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
| | - Sergey Petryakov
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
| | - David J. Lurie
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
- Aberdeen Biomedical Imaging Centre, University of Aberdeen, Foresterhill, Aberdeen, Scotland, UK AB25 2ZD
| | - Jay L. Zweier
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
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28
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Benial AMF, Utsumi H, Ichikawa K, Murugesan R, Yamada KI, Kinoshita Y, Naganuma T, Kato M. Dynamic nuclear polarization studies of redox-sensitive nitroxyl spin probes in liposomal solution. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 204:131-138. [PMID: 20226702 DOI: 10.1016/j.jmr.2010.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Revised: 02/17/2010] [Accepted: 02/17/2010] [Indexed: 05/28/2023]
Abstract
Overhauser-enhanced magnetic resonance imaging (OMRI) studies of a membrane-permeable nitroxyl spin probe, (2)H-enriched 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl (MC-PROXYL), used in simultaneous molecular imaging is reported. Phantom imaging was performed with liposomal solutions of MC-PROXYL at varying spin probe and liposome concentrations using a field-cycle mode, custom-built OMRI scanner. Dynamic nuclear polarization (DNP) spectra of the liposomal solution of the spin probe, measured at 14.529mT using a 5mT sweep of the electron paramagnetic resonance (EPR) irradiation field showed splitting of the low and high filed hyperfine lines. Spectral measurements using D(2)O and a spin broadening agent, K(3)Fe(CN)(6) confirmed that these peaks originated from water molecules in two different environments, compartmentalized with liposomes. The nuclear Overhauser enhancement measured at different EPR irradiation times and power levels showed reduction in water nuclear magnetic resonance (NMR) signal enhancement in liposomal membrane due to the reduction in the coupling constant, rho. This study illustrates that OMRI can be used to differentiate between the intra- and extra- membrane water by loading the liposome vesicles with a lipid-permeable nitroxyl spin probe.
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Affiliation(s)
- A Milton Franklin Benial
- Department of Bio-functional Science, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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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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Mellet P, Massot P, Madelin G, Marque SRA, Harte E, Franconi JM, Thiaudière E. New concepts in molecular imaging: non-invasive MRI spotting of proteolysis using an Overhauser effect switch. PLoS One 2009; 4:e5244. [PMID: 19396361 PMCID: PMC2671144 DOI: 10.1371/journal.pone.0005244] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 03/23/2009] [Indexed: 11/18/2022] Open
Abstract
Background Proteolysis, involved in many processes in living organisms, is tightly regulated in space and time under physiological conditions. However deregulation can occur with local persistent proteolytic activities, e.g. in inflammation, cystic fibrosis, tumors, or pancreatitis. Furthermore, little is known about the role of many proteases, hence there is a need of new imaging methods to visualize specifically normal or disease-related proteolysis in intact bodies. Methodology/Principal Findings In this paper, a new concept for non invasive proteolysis imaging is proposed. Overhauser-enhanced Magnetic Resonance Imaging (OMRI) at 0.2 Tesla was used to monitor the enzymatic hydrolysis of a nitroxide-labeled protein. In vitro, image intensity switched from 1 to 25 upon proteolysis due to the associated decrease in the motional correlation time of the substrate. The OMRI experimental device used in this study is consistent with protease imaging in mice at 0.2 T without significant heating. Simulations show that this enzymatic-driven OMRI signal switch can be obtained at lower frequencies suitable for larger animals or humans. Conclusions/Significance The method is highly sensitive and makes possible proteolysis imaging in three dimensions with a good spatial resolution. Any protease could be targeted specifically through the use of taylor-made cleavable macromolecules. At short term OMRI of proteolysis may be applied to basic research as well as to evaluate therapeutic treatments in small animal models of experimental diseases.
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Affiliation(s)
- Philippe Mellet
- INSERM IFR 004, and Magnetic Resonance Center CNRS UMR 5536 University Victor Segalen Bordeaux, Bordeaux, France.
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31
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Liu Y, Villamena FA, Sun J, Wang TY, Zweier JL. Esterified trityl radicals as intracellular oxygen probes. Free Radic Biol Med 2009; 46:876-83. [PMID: 19135524 PMCID: PMC2673998 DOI: 10.1016/j.freeradbiomed.2008.12.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 11/17/2008] [Accepted: 12/11/2008] [Indexed: 10/21/2022]
Abstract
Triarylmethyl (trityl) radicals exhibit high stability and narrow linewidth under physiological conditions which provide high sensitivity and resolution for the measurement of O2 concentrations, making them attractive as EPR oximetry probes. However, the application of previously available compounds has been limited by their poor intracellular permeability. We recently reported the synthesis and characterization of esterified trityl radicals as potential intracellular EPR probes and their oxygen sensitivity, redox properties, and enzyme-mediated hydrolysis were investigated. In this paper, we report the cellular permeability and stability of these trityls in the presence of bovine aortic endothelial cells. Results show that the acetoxymethoxycarbonyl-containing trityl AMT-02 exhibits high stability in the presence of cells and can be effectively internalized. The intracellular hydrolysis of AMT-02 to the carboxylate form of the trityl (CT-03) was also observed. In addition, this internalized trityl probe was applied to measure intracellular O2 concentrations and the effects of menadione and KCN on the rates of O2 consumption in endothelial cells. This study demonstrates that these esterified trityl radicals can function as effective EPR oximetry probes measuring intracellular O2 concentration and consumption.
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Affiliation(s)
- Yangping Liu
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, Columbus, OH 43210, USA
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32
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Charlier N, Driesschaert B, Wauthoz N, Beghein N, Préat V, Amighi K, Marchand-Brynaert J, Gallez B. Nano-emulsions of fluorinated trityl radicals as sensors for EPR oximetry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 197:176-180. [PMID: 19128993 DOI: 10.1016/j.jmr.2008.12.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 11/24/2008] [Accepted: 12/15/2008] [Indexed: 05/27/2023]
Abstract
This article reports the development and evaluation of two nano-emulsions (F45T-03/HFB and F15T-03/PFOB) containing fluorinated trityl radicals dissolved in perfluorocarbons. Preparation with a high-pressure homogenizer conferred sub-micronic size to both nano-emulsions. In vitro and in vivo EPR spectroscopy showed that the nano-emulsions had much greater oxygen sensitivity than the hydrophilic trityl, CT-03. In vivo experiments in rodents confirmed the ability of the nano-emulsions to follow the changes in oxygen concentration after induced ischemia. Histological evaluation of the tissue injected with the nano-emulsions revealed some acute toxicity for the F45T-03/HFB nano-emulsion but none for the F15T-03/PFOB nano-emulsion. These new formulations should be considered for further EPR oximetry experiments in pathophysiological situations where subtle changes in tissue oxygenation are expected.
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Affiliation(s)
- N Charlier
- Université catholique de Louvain, Laboratory of Biomedical Magnetic Resonance, REMA, Brussels, Belgium
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33
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Driesschaert B, Charlier N, Gallez B, Marchand-Brynaert J. Synthesis of two persistent fluorinated tetrathiatriarylmethyl (TAM) radicals for biomedical EPR applications. Bioorg Med Chem Lett 2008; 18:4291-3. [DOI: 10.1016/j.bmcl.2008.06.100] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 06/27/2008] [Accepted: 06/28/2008] [Indexed: 11/28/2022]
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34
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Vicent MJ, Dieudonné L, Carbajo RJ, Pineda-Lucena A. Polymer conjugates as therapeutics: future trends, challenges and opportunities. Expert Opin Drug Deliv 2008; 5:593-614. [DOI: 10.1517/17425247.5.5.593] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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35
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Dhimitruka I, Velayutham M, Bobko AA, Khramtsov VV, Villamena FA, Hadad CM, Zweier JL. Large-scale synthesis of a persistent trityl radical for use in biomedical EPR applications and imaging. Bioorg Med Chem Lett 2007; 17:6801-5. [PMID: 17964156 DOI: 10.1016/j.bmcl.2007.10.030] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 10/09/2007] [Accepted: 10/10/2007] [Indexed: 11/26/2022]
Abstract
Tetrathiatriarylmethyl radicals are ideal spin probes for biological electron paramagnetic resonance (EPR) spectroscopy and imaging. The wide application of trityl radicals as biosensors of oxygen or other biological radicals was hampered by the lack of affordable large-scale syntheses. We report the large-scale synthesis of the Finland trityl radical using an improved addition protocol of the aryl lithium monomer to methylchloroformate. A new reaction for the formal one-electron reduction of trityl alcohols to trityl radicals using neat trifluoroacetic acid is reported as well. Initial applications show that the compound is very sensitive to molecular oxygen. It has already provided high-resolution EPR images on large aqueous samples and should be suitable for a broad range of in vivo applications.
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Affiliation(s)
- Ilirian Dhimitruka
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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36
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Davda S, Bezabeh T. Advances in methods for assessing tumor hypoxia in vivo: implications for treatment planning. Cancer Metastasis Rev 2007; 25:469-80. [PMID: 17029029 DOI: 10.1007/s10555-006-9009-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Tumor hypoxia and its downstream effects have remained of considerable interest for decades due to its negative impact on response to various cancer therapies and promotion of metastasis. Diagnosing hypoxia non-invasively can provide a significant advancement in cancer treatment and is the dire necessity for implementing specific targeted therapies now emerging to treat different aspects of cancer. A variety of techniques are being proposed to do so. However, none of them has yet been established in the clinical arena. This review summarizes the methods currently available to assess tumor hypoxia in vivo and their respective advantages and shortcomings. It also points out the impedances that need to be overcome to establish any particular method in the clinic, along with a broad overview of requirements for further advancement in this sphere of cancer research.
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Affiliation(s)
- Sonal Davda
- Institute for Biodiagnostics, National Research Council, 435 Ellice Avenue, Winnipeg, Manitoba, Canada, R3B 1Y6
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37
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Kawada Y, Hirata H, Fujii H. Use of multi-coil parallel-gap resonators for co-registration EPR/NMR imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 184:29-38. [PMID: 17029883 DOI: 10.1016/j.jmr.2006.09.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 09/12/2006] [Accepted: 09/12/2006] [Indexed: 05/12/2023]
Abstract
This article reports experimental investigations on the use of RF resonators for continuous-wave electron paramagnetic resonance (cw-EPR) and proton nuclear magnetic resonance (NMR) imaging. We developed a composite resonator system with multi-coil parallel-gap resonators for co-registration EPR/NMR imaging. The resonance frequencies of each resonator were 21.8MHz for NMR and 670MHz for EPR. A smaller resonator (22mm in diameter) for use in EPR was placed coaxially in a larger resonator (40mm in diameter) for use in NMR. RF magnetic fields in the composite resonator system were visualized by measuring a homogeneous 4-hydroxy-2,2,6,6-tetramethyl-piperidinooxy (4-hydroxy-TEMPO) solution in a test tube. A phantom of five tubes containing distilled water and 4-hydroxy-TEMPO solution was also measured to demonstrate the potential usefulness of this composite resonator system in biomedical science. An image of unpaired electrons was obtained for 4-hydroxy-TEMPO in three tubes, and was successfully mapped on the proton image for five tubes. Technical problems in the implementation of a composite resonator system are discussed with regard to co-registration EPR/NMR imaging for animal experiments.
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Affiliation(s)
- Yuuki Kawada
- Department of Electrical Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan
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38
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Matsumoto S, Yamada K, Hirata H, Yasukawa K, Hyodo F, Ichikawa K, Utsumi H. Advantageous application of a surface coil to EPR irradiation in overhauser-enhanced MRI. Magn Reson Med 2007; 57:806-11. [PMID: 17390363 DOI: 10.1002/mrm.21198] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The present study describes the advantageous application of a surface coil to electron paramagnetic resonance (EPR) irradiation in Overhauser-enhanced MRI (OMRI). OMRI is a double-resonance method for imaging free radicals based on the Overhauser effect. Proton NMR images are recorded without and with EPR irradiation of the free radical resonance, which results in a difference proton image that shows signal enhancement in spatial regions that contain the free radical. To obtain good signal enhancement in OMRI, very high RF power and a long EPR irradiation time are required. To improve sensitivity and shorten the image acquisition time, especially for localized (and topical) applications, we developed and tested a surface-coil-type EPR irradiation coil. Theoretical calculations and experimental data showed that EPR irradiation through the surface coil could ameliorate the localized Overhauser enhancement, which was related to the ratio of B(1) surface coil/B(1) volume coil in the region of interest (ROI), as expected. The increased sensitivity could also be converted into a shortened EPR irradiation time, resulting in fast data acquisition. For biomedical applications, the use of a surface coil (as opposed to a conventional volume coil) could decrease the total RF power deposition in the sample required to obtain the same Overhauser enhancement in the ROI.
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Affiliation(s)
- Shingo Matsumoto
- Department of Biofunctional Science, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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39
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Petryakov S, Samouilov A, Roytenberg M, Li H, Zweier JL. Modified Alderman-Grant resonator with high-power stability for proton electron double resonance imaging. Magn Reson Med 2006; 56:654-9. [PMID: 16902975 DOI: 10.1002/mrm.20992] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Proton-electron double resonance imaging (PEDRI) requires a dual EPR/NMR resonator. In order to saturate electron spins, long high-power RF EPR pulses are needed. Dissipated power causes resonator and sample heating, resulting in instability of the resonator frequency and coupling, which in turn causes a reduction in sensitivity. To overcome this problem, we designed, built, and tested a modified Alderman-Grant (MAG) resonator for in vivo and in vitro applications. We improved the temperature stability by using fused quartz in critical structural components of the resonator and employing a design that minimized moving parts. All of the components of the resonator and matching circuit, including coupling capacitors, were rigidly positioned on the surface of the quartz tube. Electrical coupling circuitry between the feeding cable and resonator was employed to provide independent coupling and tuning adjustments, which improved the ease and speed of operation. The equivalent schematic of the matching circuit is presented along with calculations of critical parameters. The resonator exhibits no frequency shift with 20 W of continuous power irradiation, and can handle intermittent power of 60 W for up to 3 min without detuning, enabling stable and reliable data acquisition for PEDRI of biological samples.
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Affiliation(s)
- Sergey Petryakov
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Columbus, Ohio 43210-1252, USA
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40
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Benial AMF, Ichikawa K, Murugesan R, Yamada KI, Utsumi H. Dynamic nuclear polarization properties of nitroxyl radicals used in Overhauser-enhanced MRI for simultaneous molecular imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 182:273-82. [PMID: 16875854 DOI: 10.1016/j.jmr.2006.06.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 06/14/2006] [Accepted: 06/26/2006] [Indexed: 05/11/2023]
Abstract
DNP parameters relevant to Overhauser-enhanced magnetic resonance imaging (OMRI) are reported for a few nitroxyl radicals and their corresponding (15)N and (2)H enriched analogues, used in simultaneous imaging by OMRI. DNP enhancement was measured at 14.529 mT, using a custom-built scanner operating in a field-cycled mode, for different concentrations, ESR irradiation times and RF power levels. DNP enhancements increased with agent concentration up to 2.5 mM and decreased above 3 mM, in tune with ESR line broadening measured at X-band as a function of the agent concentration. The proton spin-lattice relaxation times (T(1)) measured at very low Zeeman field (14.529 mT) and the longitudinal relaxivity parameters were estimated. The relaxivity parameters were in good agreement with those independently computed from the linear region of the concentration dependent enhancement. The leakage factor showed an asymptotic increase with increasing agent concentration. The coupling parameters of (14)N- and (15)N-labeled carbamoyl-PROXYL showed the interaction between the electron and nuclear spins to be mainly dipolar in origin. Upon (2)H labeling, about 70% and 40% increases in enhancement for (15)N- and (14)N-labeled nitroxyl agents were observed, respectively. It is envisaged that the results reported here may enable better understanding of the factors determining DNP enhancement to design suitable 'beacons' for simultaneous molecular imaging by OMRI.
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Affiliation(s)
- A Milton Franklin Benial
- Department of Bio-functional Science, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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41
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Fujii H, Aoki M, Haishi T, Itoh K, Sakata M. Development of an ESR/MR dual-imaging system as a tool to detect bioradicals. Magn Reson Med Sci 2006; 5:17-23. [PMID: 16785723 DOI: 10.2463/mrms.5.17] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A system combining electron spin resonance imaging (ESRI) with another imaging modality capable of enabling visualization of the distribution of bioradicals on an anatomical map of the specimens would be a superior biomedical imaging system. We describe the development of an ESR/MR dual-imaging system with one permanent magnet and the biomedical applications of this system. The magnetic circuit developed for the ESR/MR dual-imaging system consisted of the permanent magnet made of Fe-Nd-B, pole pieces, and poke. The permanent magnet was installed on the MR side only, and the ESR side was made of pole pieces only. The magnetic field was adjusted to 0.5T at MR and to 0.042T at ESR. The overall dimensions of the magnet developed for the ESR/MR imaging system were 460 (W)x440 (D)x460 (H) mm, and it weighed 220 kg. The distance of each center for the magnet for ESR and MR imaging could be set as close as 200 mm. The entire ESR/MR imaging system can be installed in a common laboratory without magnetic shielding. MR images of plants (myoga) and small animals (mice and rats) were successfully acquired with or without ESR operation. ESR spectra of nitroxyl spin probes were also measured, even with MRI operation. ESR signals of triarylmethyl derivatives with narrow line-width (0.026 mT) were observed in living mice while MRI was operating. The ESR/MR imaging dual functions work properly with no electric or magnetic interference. The ESR/MR dual images demonstrate that this system enables visualization of the distribution of bioradicals on the anatomical map of the object.
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Affiliation(s)
- Hirotada Fujii
- School of Health Sciences, Sapporo Medical University, Chuo-ku, Sapporo, Japan.
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42
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Deng Y, Shet K, Li H, Kuppusamy P, Zweier JL. Real-time calculation and visualization of spectra in field-cycled dynamic nuclear polarization spectroscopy. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2006; 82:67-72. [PMID: 16563554 DOI: 10.1016/j.cmpb.2006.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 02/03/2006] [Accepted: 02/05/2006] [Indexed: 05/08/2023]
Abstract
Field-cycled dynamic nuclear polarization (FC-DNP), which is based on the Overhauser effect, provides a new way to perform in vivo measurements of free radicals in biological systems. Since it measures the alterations of the nuclear magnetic resonance (NMR) signal in the presence of paramagnetic molecules, a customized program is usually needed in FC-DNP experiments to extract spectral information from the acquired NMR signals. While this program can be designed to calculate the spectrum after all the NMR signals are collected, the batch-processing mode inevitably causes delay and is not convenient for in vivo applications. In this paper, we report the development of a real-time DNP spectrum calculation and visualization program, called RT_DNP, for FC-DNP experiments. A dynamic data exchange (DDE) client was implemented to enable real-time receipt of the system information and the NMR signals from a commercial NMR console. The received NMR signals and experimental parameters were then used to calculate the DNP spectrum during the data acquisition. The real-time DNP spectrum calculation and visualization program was tested in experiments. A seamless integration of the program into a commercial NMR console has been achieved.
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Affiliation(s)
- Yuanmu Deng
- Center for Biomedical EPR Spectroscopy and Imaging, 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, OH 43210, USA
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43
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Li H, He G, Deng Y, Kuppusamy P, Zweier JL. In vivo proton electron double resonance imaging of the distribution and clearance of nitroxide radicals in mice. Magn Reson Med 2006; 55:669-75. [PMID: 16463344 DOI: 10.1002/mrm.20804] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Proton electron double resonance imaging (PEDRI) is an emerging technique that utilizes the Overhauser effect to enable in vivo and in vitro imaging of free radicals in biological systems. Nitroxide spin probes enable measurement of tissue redox state based on their reduction to diamagnetic hydroxylamines. PEDRI instrumentation at 0.02 T was applied to assess the ability to image the in vivo distribution, clearance, and metabolism of nitroxide radicals in living mice. Using phantoms of 2,2,5,5-tetramethyl-3-carboxylpyrrolidine-N-oxyl (PCA) in normal saline the dependence of the enhancement on RF power and spin probe concentration was determined. Enhancements of up to -23 were obtained in phantoms with 2 mM levels. Maximum enhancement of -7 was observed in vivo. Coronal images of nitroxide-infused mice enabled visualization of the kinetics of spin probe uptake and clearance in different organs including the great vessels, heart, lungs, kidneys, and bladder with an in-plane spatial resolution of 0.6 mm. PEDRI of living mice was also performed using 3-carbamoyl-proxyl and 2,2,6,6-tetramethyl-4-oxopiperidine-N-oxyl to compare the different rate of clearance and metabolism among different nitroxide probes. PCA, due to its intravascular compartmentalization, provided the sharpest contrast for the vascular system and highest enhancement values in the PEDRI images among the three nitroxides.
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Affiliation(s)
- Haihong Li
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 04210-1252, USA
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44
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Eaton GR, Eaton SS. EPR Spectrometers at Frequencies Below X-band. EPR: INSTRUMENTAL METHODS 2004. [DOI: 10.1007/978-1-4419-8951-2_2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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45
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Liebgott T, Li H, Deng Y, Zweier JL. Proton electron double resonance imaging (PEDRI) of the isolated beating rat heart. Magn Reson Med 2003; 50:391-9. [PMID: 12876716 DOI: 10.1002/mrm.10534] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Proton electron double resonance imaging (PEDRI) is a double resonance technique where proton MRI is performed with irradiation of a paramagnetic solute. A low-field PEDRI system was developed at 20.1 mT suitable for imaging free radicals in biological samples. With a new small dual resonator, PEDRI was applied to image nitroxide free radicals in isolated beating rat hearts. Experiments with phantoms showed maximum image enhancement factors (IEF) of 42 or 28 with TEMPONE radical concentrations of 2-3 mM at EPR irradiation powers of 12W or 6W, respectively. In the latter case, image resolution better than 0.5 mm and radical sensitivity of 5 microM was obtained. For isolated heart studies, EPR irradiation power of 6W provided optimal compromise of modest sample heating with good SNR. Only a small increase in temperature of about 1 degrees C was observed, while cardiac function remained within 10% of control values. With infusion of 3 mM TEMPONE an IEF of 15 was observed enabling 2D or 3D images to be obtained in 27 sec or 4.5 min, respectively. These images visualized the change in radical distribution within the heart during infusion and clearance. Thus, PEDRI enables rapid and high-quality imaging of free radical uptake and clearance in perfused hearts and provides a useful technique for studying cardiac radical metabolism.
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Affiliation(s)
- Thibaut Liebgott
- Center for Biomedical EPR Spectroscopy and Imaging, the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
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46
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Current awareness in NMR in biomedicine. NMR IN BIOMEDICINE 2003; 16:56-65. [PMID: 12619641 DOI: 10.1002/nbm.799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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