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Epel B, Viswakarma N, Hameed S, Freidin MM, Abrams CK, Kotecha M. Assessment of blood-brain barrier leakage and brain oxygenation in Connexin-32 knockout mice with systemic neuroinflammation using pulse electron paramagnetic resonance imaging techniques. Magn Reson Med 2024; 91:2519-2531. [PMID: 38193348 PMCID: PMC10997480 DOI: 10.1002/mrm.29994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 11/30/2023] [Accepted: 12/13/2023] [Indexed: 01/10/2024]
Abstract
PURPOSE The determination of blood-brain barrier (BBB) integrity and partial pressure of oxygen (pO2) in the brain is of substantial interest in several neurological applications. This study aimed to assess the feasibility of using trityl OX071-based pulse electron paramagnetic resonance imaging (pEPRI) to provide a quantitative estimate of BBB integrity and pO2 maps in mouse brains as a function of neuroinflammatory disease progression. METHODS Five Connexin-32 (Cx32)-knockout (KO) mice were injected with lipopolysaccharide to induce neuroinflammation for imaging. Three wild-type mice were also used to optimize the imaging procedure and as control animals. An additional seven Cx32-KO mice were used to establish the BBB leakage of trityl using the colorimetric assay. All pEPRI experiments were performed using a preclinical instrument, JIVA-25 (25 mT/720 MHz), at times t = 0, 4, and 6 h following lipopolysaccharide injection. Two pEPRI imaging techniques were used: (a) single-point imaging for obtaining spatial maps to outline the brain and calculate BBB leakage using the signal amplitude, and (b) inversion-recovery electron spin echo for obtaining pO2 maps. RESULTS A statistically significant change in BBB leakage was found using pEPRI with the progression of inflammation in Cx32 KO animals. However, the change in pO2 values with the progression of inflammation for these animals was not statistically significant. CONCLUSIONS For the first time, we show the ability of pEPRI to provide pO2 maps in mouse brains noninvasively, along with a quantitative assessment of BBB leakage. We expect this study to open new queries from the field to explore the pathology of many neurological diseases and provide a path to new treatments.
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Affiliation(s)
- Boris Epel
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois, USA
| | - Navin Viswakarma
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Safa Hameed
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
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Epel B, Viswakarma N, Sundramoorthy SV, Pawar NJ, Kotecha M. Oxygen Imaging of a Rabbit Tumor Using a Human-Sized Pulse Electron Paramagnetic Resonance Imager. Mol Imaging Biol 2024; 26:403-410. [PMID: 37715089 DOI: 10.1007/s11307-023-01852-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 09/17/2023]
Abstract
PURPOSE Spatial heterogeneity in tumor hypoxia is one of the most important factors regulating tumor growth, development, aggressiveness, metastasis, and affecting treatment outcome. Most solid tumors are known to have hypoxia or low oxygen levels (pO2 ≤10 torr). Electron paramagnetic resonance oxygen imaging (EPROI) is an emerging oxygen mapping technology. EPROI utilizes the linear relationship between the relaxation rates of the injectable OX071 trityl spin probe and the partial oxygen pressure (pO2). However, most of the EPROI studies have been limited to mouse models of solid tumors because of the instrument-size limitations. The purpose of this work was to develop a human-sized 9-mT (250 MHz resonance frequency, 60 cm bore size) pulse EPROI instrument and evaluate its performance with rabbit VX-2 tumor oxygen imaging. METHODS A New Zealand white rabbit with a 3.2-cm VX-2 tumor in the calf muscle was imaged using the human-sized EPROI instrument and a 2.25-in. ID volume coil. The animal received a ~8-min intravenous injection of OX071 (5.2 mL total volume at 72 mM concentration) and, after 75 min, an intratumoral injection (120 μL total at 5 mM OX071 concentration) and underwent EPROI. At the end of the experiments, MRI was performed using a preclinical 9.4-T MRI system to outline the tumor boundaries. RESULTS For the first time, a human-sized pulse EPROI instrument with a 60-cm bore size/250-MHz frequency was built and evaluated using rabbit tumor oxygen imaging. For the first time, the systemic IV injection of the oxygen-sensitive trityl OX071 spin probe was used for an animal of this size. The resulting EPROI image from the IV injection showed complete tumor coverage. The image obtained after intratumoral injection showed localized coverage in the upper lobe of the tumor, demonstrating the need for improved intratumoral injection protocol. CONCLUSIONS This study demonstrates the performance of the world's first human-sized pulse EPROI instrument. It also demonstrates that the EPROI of larger animals can be performed using the systemic injection of a manageable amount of the spin probe. This brings EPROI one step closer to clinical applications in cancer therapies. Oxygen imaging is a platform technology, and the instrument and techniques developed here will also be useful for other clinical applications.
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Affiliation(s)
- Boris Epel
- O2M Technologies, LLC, Chicago, IL, 60612, USA.
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL, 60637, USA.
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Li T, Murley GA, Liang X, Chin RL, de la Cerda J, Schuler FW, Pagel MD. Evaluations of an Early Change in Tumor Pathophysiology in Response to Radiotherapy with Oxygen Enhanced Electron Paramagnetic Resonance Imaging (OE EPRI). Mol Imaging Biol 2024; 26:448-458. [PMID: 38869818 DOI: 10.1007/s11307-024-01925-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 05/15/2024] [Accepted: 05/26/2024] [Indexed: 06/14/2024]
Abstract
PURPOSE Electron Paramagnetic Resonance Imaging (EPRI) can image the partial pressure of oxygen (pO2) within in vivo tumor models. We sought to develop Oxygen Enhanced (OE) EPRI that measures tumor pO2 with breathing gases of 21% O2 (pO221%) and 100% O2 (pO2100%), and the differences in pO2 between breathing gases (ΔpO2). We applied OE EPRI to study the early change in tumor pathophysiology in response to radiotherapy in two tumor models of pancreatic cancer. PROCEDURES We developed a protocol that intraperitoneally administered OX071, a trityl radical contrast agent, and then acquired anatomical MR images to localize the tumor. Subsequently, we acquired two pO221% and two pO2100% maps using the T1 relaxation time of OX071 measured with EPRI and a R1-pO2 calibration of OX071. We studied 4T1 flank tumor model to evaluate the repeatability of OE EPRI. We then applied OE EPRI to study COLO 357 and Su.86.86 flank tumor models treated with 10 Gy radiotherapy. RESULTS The repeatability of mean pO2 for individual tumors was ± 2.6 Torr between successive scans when breathing 21% O2 or 100% O2, representing a precision of 9.6%. Tumor pO221% and pO2100% decreased after radiotherapy for both models, although the decreases were not significant or only moderately significant, and the effect sizes were modest. For comparison, ΔpO2 showed a large, highly significant decrease after radiotherapy, and the effect size was large. MANOVA and analyses of the HF10 hypoxia fraction provided similar results. CONCLUSIONS EPRI can evaluate tumor pO2 with outstanding precision relative to other imaging modalities. The change in ΔpO2 before vs. after treatment was the best parameter for measuring the early change in tumor pathophysiology in response to radiotherapy. Our studies have established ΔpO2 from OE EPRI as a new parameter, and have established that OE EPRI is a valuable new methodology for molecular imaging.
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Affiliation(s)
- Tianzhe Li
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
- The University of Texas Health Science Center, Houston, TX, 77030, USA
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE, 68105, USA
| | - Grace A Murley
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
- The University of Texas Health Science Center, Houston, TX, 77030, USA
| | - Xiaofei Liang
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Renee L Chin
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
- The University of Texas Health Science Center, Houston, TX, 77030, USA
| | - Jorge de la Cerda
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - F William Schuler
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Mark D Pagel
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, 77030, USA.
- Department of Medical Physics, University of Wisconsin, Madison, WI, 53705, USA.
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Petryakov SV, Kmiec MM, Ubert CS, Kassey VB, Schaner PE, Kuppusamy P. Surface dielectric resonator for in vivo EPR measurements. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 362:107690. [PMID: 38692250 PMCID: PMC11102834 DOI: 10.1016/j.jmr.2024.107690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/16/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
This research report describes a novel surface dielectric resonator (SDR) with a flexible connector for in vivo electron paramagnetic resonance (EPR) spectroscopy. Contrary to the conventional cavity or surface loop-gap resonators, the newly developed SDR is constructed from a ceramic dielectric material, and it is tuned to operate at the L-band frequency band (1.15 GHz) in continuous-wave mode. The SDR is designed to be critically coupled and capable of working with both very lossy samples, such as biological tissues, and non-lossy materials. The SDR was characterized using electromagnetic field simulations, assessed for sensitivity with a B1 field-perturbation method, and validated with tissue phantoms using EPR measurements. The results showed remarkably higher sensitivity in lossy tissue phantoms than the previously reported multisegment surface-loop resonators. The new SDR can provide potential new insights for advancements in the application of in vivo EPR spectroscopy for biological measurements, including clinical oximetry.
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Affiliation(s)
- Sergey V Petryakov
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Maciej M Kmiec
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Conner S Ubert
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA; Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Victor B Kassey
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Philip E Schaner
- Department of Radiation Oncology and Applied Sciences, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Periannan Kuppusamy
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA; Thayer School of Engineering, Dartmouth College, Hanover, NH, USA; Department of Radiation Oncology and Applied Sciences, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
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Kishimoto S, Devasahayam N, Chandramouli GVR, Murugesan R, Otowa Y, Yamashita K, Yamamoto K, Brender JR, Krishna MC. Evaluation of a deuterated triarylmethyl spin probe for in vivo R 2 ∗-based EPR oximetric imaging with enhanced dynamic range. Magn Reson Med 2024; 91:413-423. [PMID: 37676121 PMCID: PMC10841161 DOI: 10.1002/mrm.29811] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/03/2023] [Accepted: 07/11/2023] [Indexed: 09/08/2023]
Abstract
PURPOSE In this study, we compared two triarylmethyl (TAM) spin probes, Ox071 and Ox063 for their efficacy in measuring tissue oxygen levels under hypoxic and normoxic conditions by R2 *-based EPR oximetry. METHODS The R2 * dependencies on the spin probe concentration and oxygen level were calibrated using deoxygenated 1, 2, 5, and 10 mM standard solutions and 2 mM solutions saturated at 0%, 2%, 5%, 10%, and 21% of oxygen. For the hypoxic model, in vivo imaging of a MIA PaCa-2 tumor implanted in the hind leg of a mouse was performed on successive days by R2 *-based EPR oximetry using either Ox071 or Ox063. For the normoxic model, renal imaging of healthy athymic mice was performed using both spin probes. The 3D images were reconstructed by single point imaging and multi-gradient technique was used to determine R2 * maps. RESULTS The signal intensities of Ox071 were approximately three times greater than that of Ox063 in the entire partial pressure of oxygen (pO2 ) range investigated. The histograms of the tumor pO2 images were skewed for both spin probes, and Ox071 showed more frequency counts at pO2 > 32 mm Hg. In the normoxic kidney model, there was a clear delineation between the high pO2 cortex and the low pO2 medulla regions. The histogram of high-resolution kidney oximetry image using Ox071 was nearly symmetrical and frequency counts were seen up to 55 mm Hg, which were missed in Ox063 imaging. CONCLUSION As an oximetric probe, Ox071 has clear advantages over Ox063 in terms of sensitivity and the pO2 dynamic range.
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Affiliation(s)
- Shun Kishimoto
- Radiation Biology Branch, Center for Cancer Research, NCI, Bethesda, Maryland, USA
- Urologic Oncology Branch, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | | | | | - Ramachandran Murugesan
- Karpaga Vinayaga Institute of Medical Sciences and Research Center, Chengalpattu, Tamil Nadu, India
| | - Yasunori Otowa
- Radiation Biology Branch, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | - Kota Yamashita
- Radiation Biology Branch, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | - Kazutoshi Yamamoto
- Radiation Biology Branch, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | - Jeffrey R Brender
- Radiation Biology Branch, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | - Murali C Krishna
- Radiation Biology Branch, Center for Cancer Research, NCI, Bethesda, Maryland, USA
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Gluth TD, Poncelet M, Gencheva M, Hoblitzell EH, Khramtsov VV, Eubank TD, Driesschaert B. Biocompatible Monophosphonated Trityl Spin Probe, HOPE71, for In Vivo Measurement of pO 2, pH, and [P i] by Electron Paramagnetic Resonance Spectroscopy. Anal Chem 2023; 95:946-954. [PMID: 36537829 PMCID: PMC9852220 DOI: 10.1021/acs.analchem.2c03476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Hypoxia, acidosis, and elevated inorganic phosphate concentration are characteristics of the tumor microenvironment in solid tumors. There are a number of methods for measuring each parameter individually in vivo, but the only method to date for noninvasive measurement of all three variables simultaneously in vivo is electron paramagnetic spectroscopy paired with a monophosphonated trityl radical, pTAM/HOPE. While HOPE has been successfully used for in vivo studies upon intratissue injection, it cannot be delivered intravenously due to systemic toxicity and albumin binding, which causes significant signal loss. Therefore, we present HOPE71, a monophosphonated trityl radical derived from the very biocompatible trityl probe, Ox071. Here, we describe a straightforward synthesis of HOPE71 starting with Ox071 and report its EPR sensitivities to pO2, pH, and [Pi] with X-band and L-band EPR spectroscopy. We also confirm that HOPE71 lacks albumin binding, shows low cytotoxicity, and has systemic tolerance. Finally, we demonstrate its ability to profile the tumor microenvironment in vivo in a mouse model of breast cancer.
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Affiliation(s)
- Teresa D. Gluth
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
| | - Marieta Gencheva
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biochemistry and Molecular Medicine, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Emily H. Hoblitzell
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Valery V. Khramtsov
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biochemistry and Molecular Medicine, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Timothy D. Eubank
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, School of Medicine, Morgantown, WV, 26506, USA
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
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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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Gertsenshteyn I, Giurcanu M, Vaupel P, Halpern H. Biological validation of electron paramagnetic resonance (EPR) image oxygen thresholds in tissue. J Physiol 2020; 599:1759-1767. [PMID: 32506448 DOI: 10.1113/jp278816] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/26/2020] [Indexed: 12/17/2022] Open
Abstract
Measuring molecular oxygen levels in vivo has been the cornerstone of understanding the effects of hypoxia in normal tissues and malignant tumors. Here we discuss the advances in a variety of partial pressure of oxygen ( P O 2 ) measurements and imaging techniques and relevant oxygen thresholds. A focus on electron paramagnetic resonance (EPR) imaging shows the validation of treating hypoxic tumours with a threshold of P O 2 ≤ 10 Torr, and demonstrates utility for in vivo oxygen imaging, as well as its current and future role in cancer studies.
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Affiliation(s)
- Inna Gertsenshteyn
- Department of Radiology, University of Chicago, IL, USA.,Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL, USA
| | - Mihai Giurcanu
- Department of Public Health Sciences, University of Chicago, IL, USA
| | - Peter Vaupel
- Department of Radiation Oncology, Medical Center, University of Freiburg, Germany.,German Cancer Consortium (DKTK), Partner site Freiburg and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Howard Halpern
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL, USA
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Kodama Y, Hyodo F, Yamato M, Yasukawa K, Minami Y, Sonoda N, Ogawa Y, Ichikawa K, Inoguchi T. Dynamic nuclear polarization magnetic resonance imaging and the oxygen-sensitive paramagnetic agent OX63 provide a noninvasive quantitative evaluation of kidney hypoxia in diabetic mice. Kidney Int 2019; 96:787-792. [PMID: 31345583 DOI: 10.1016/j.kint.2019.04.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 04/21/2019] [Accepted: 04/25/2019] [Indexed: 12/24/2022]
Abstract
Renal hypoxia may play an important role in the progression of diabetic nephropathy. However, tools that noninvasively and quantitatively measure oxygen tension in the kidney are lacking. Here, we evaluated the feasibility of a noninvasive and quantitative imaging technique using dynamic nuclear polarization magnetic resonance imaging (DNP-MRI) in combination with the oxygen-sensitive paramagnetic agent OX63 for measuring oxygen tension in the kidney. Our results demonstrate that the DNP-MRI technique can yield quantitative maps of oxygen tension in the mouse renal cortex. Using this procedure, we also showed that oxygen tension was less elevated in the renal cortex of both streptozotocin-induced type 1 diabetic mice and db/db mice, a model of type 2 diabetes, than in the renal cortex of age-matched control mice of each respective model. Oxygen tension in streptozotocin-exposed mice was significantly improved by insulin treatment. Thus, the noninvasive and quantitative DNP-MRI technique appears to be useful for studying the pathophysiological role of hypoxia.
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Affiliation(s)
- Yoshimi Kodama
- Department of Internal Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Fuminori Hyodo
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan; Frontier Science for Imaging, Department of Radiology, School of Medicine Gifu University, Gifu, Japan; Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Mayumi Yamato
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan; Physical Chemistry for Life Science Laboratory, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Keiji Yasukawa
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan; Laboratory of Advanced Pharmacology, Daiichi University of Pharmacy, Fukuoka, Japan
| | - Yohei Minami
- Department of Internal Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Noriyuki Sonoda
- Department of Internal Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan
| | - Yoshihiro Ogawa
- Department of Internal Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Kazuhiro Ichikawa
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan; Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki International University, Nagasaki, Japan
| | - Toyoshi Inoguchi
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan; Fukuoka City Health Promotion Support Center, Fukuoka City, Japan.
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Qu Y, Li Y, Tan X, Zhai W, Han G, Hou J, Liu G, Song Y, Liu Y. Synthesis and Characterization of Hydrophilic Trityl Radical TFO for Biomedical and Biophysical Applications. Chemistry 2019; 25:7888-7895. [PMID: 30972843 DOI: 10.1002/chem.201900262] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Indexed: 12/18/2022]
Abstract
Tetrathiatriarylmethyl (TAM, trityl) radicals have found wide applications as spin probes/labels for EPR spectroscopy and imaging, and as polarizing agents for dynamic nuclear polarization. The high hydrophilicity of TAM radicals is essential for their biomedical applications. However, the synthesis of hydrophilic TAM radicals (e.g., OX063) is extremely challenging and has only been reported in the patent literature, to date. Herein, an efficient synthesis of a highly water-soluble TAM radical bis(8-carboxyl-2,2,6,6-tetramethylbenzo[1,2-d:4,5-d']bis([1,3]dithiol-4-yl)-mono-(8-carboxyl-2,2,6,6-tetrakis(2-hydroxyethyl)benzo[1,2-d:4,5-d']bis([1,3]dithiol-4-yl)methyl (TFO), which contains four additional hydroxylethyl groups, relative to the Finland trityl radical CT-03, is reported. Similar to OX063, TFO exhibits excellent properties, including high water solubility in phosphate buffer, low log P, low pKa , long relaxation times, and negligible binding with bovine serum albumin. On the other hand, TFO has a sharper EPR line and higher O2 sensitivity than those of OX063. Therefore, in combination with its facile synthesis, TFO should find wide applications in magnetic resonance related fields and this synthetic approach would shed new light on the synthesis of other hydrophilic TAM radicals.
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Affiliation(s)
- Yuying Qu
- Tianjin Key Laboratory on Technologies Enabling, Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P.R. China
| | - Yingchun Li
- 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
| | - Weixiang Zhai
- 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
| | - Jingli Hou
- Tianjin Key Laboratory on Technologies Enabling, Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P.R. China
| | - Guoquan Liu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing, 100191, 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
| | - 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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Chen NT, Barth ED, Lee TH, Chen CT, Epel B, Halpern HJ, Lo LW. Highly sensitive electron paramagnetic resonance nanoradicals for quantitative intracellular tumor oxymetric images. Int J Nanomedicine 2019; 14:2963-2971. [PMID: 31118615 PMCID: PMC6503311 DOI: 10.2147/ijn.s194779] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/11/2019] [Indexed: 01/25/2023] Open
Abstract
Purpose: Tumor oxygenation is a critical parameter influencing the efficacy of cancer therapy. Low levels of oxygen in solid tumor have been recognized as an indicator of malignant progression and metastasis, as well as poor response to chemo- and radiation therapy. Being able to measure oxygenation for an individual's tumor would provide doctors with a valuable way of identifying optimal treatments for patients. Methods: Electron paramagnetic resonance imaging (EPRI) in combination with an oxygen-measuring paramagnetic probe was performed to measure tumor oxygenation in vivo. Triarylmethyl (trityl) radical exhibits high specificity, sensitivity, and resolution for quantitative measurement of O2 concentration. However, its in vivo applications in previous studies have been limited by the required high dosage, its short half-life, and poor intracellular permeability. To address these limitations, we developed high-capacity nanoformulated radicals that employed fluorescein isothiocyanate-labeled mesoporous silica nanoparticles (FMSNs) as trityl radical carriers. The high surface area nanostructure and easy surface modification of physiochemical properties of FMSNs enable efficient targeted delivery of highly concentrated, nonself-quenched trityl radicals, protected from environmental degradation and dilution. Results: We successfully designed and synthesized a tumor-targeted nanoplatform as a carrier for trityl. In addition, the nanoformulated trityl does not affect oxygen-sensing capacity by a self-relaxation or broadening effect. The FMSN-trityl exhibited high sensitivity/response to oxygen in the partial oxygen pressure range from 0 to 155 mmHg. Furthermore, MSN-trityl displayed outstanding intracellular oxygen mapping in both in vitro and in vivo animal studies. Conclusion: The highly sensitive nanoformulated trityl spin probe can profile intracellular oxygen distributions of tumor in a real-time and quantitative manner using in vivo EPRI.
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Affiliation(s)
- Nai-Tzu Chen
- Institute of New Drug Development, China Medical University, Taichung 40402, Taiwan
| | - Eugene D Barth
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Tsung-Hsi Lee
- Department of Biological Science and Technology, China Medical University, Taichung 40402, Taiwan
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA
| | - Boris Epel
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Howard J Halpern
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Leu-Wei Lo
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA.,Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan 35053, Taiwan
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12
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Pursley R, Enomoto A, Wu H, Brender JR, Pohida T, Subramanian S, Krishna MC, Devasahayam N. Towards reduction of SAR in scaling up in vivo pulsed EPR imaging to larger objects. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 299:42-48. [PMID: 30579225 PMCID: PMC6753525 DOI: 10.1016/j.jmr.2018.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 12/10/2018] [Accepted: 12/13/2018] [Indexed: 06/09/2023]
Abstract
An excessive RF power requirement is one of the main obstacles in the clinical translation of EPR imaging. The radio frequency (RF) pulses used in EPR imaging to excite electron spins must be very short to match their fast relaxation. With traditional pulse schemes and ninety degree flip angles, this can lead to either unsafe specific absorption rate (SAR) levels or unfeasibly long repetition times. In spectroscopy experiments, it has been shown that stochastic excitation and correlation detection can reduce the power while maintaining sensitivity but have yet to be applied to imaging experiments. Stochastic excitation is implemented using a pseudo-random phase modulation of the input stimulus. Using a crossed coil resonator assembly comprised of an outer saddle coil and an inner surface coil, it was possible to obtain a minimum isolation of ∼50 dB across a 12 MHz bandwidth. An incident peak RF power of 5 mW was used to excite the system. The low background signal obtained from this resonator allowed us to generate images with 32 dB (>1000:1) signal-to-noise ratio (SNR) while exciting with a traditional pulse sequence in a phantom containing the solid paramagnetic probe NMP-TCNQ (N-methyl pyridinium tetracyanoquinodimethane). Using two different stochastic excitation schemes, we were able to achieve a greater than 4-fold increase in SNR at the same peak power and number of averages, compared to single pulse excitation. This procedure allowed imaging at significantly lower RF power levels than used in conventional EPR imaging system configurations. Similar techniques may enable clinical applications for EPR imaging by facilitating the use of larger RF coils while maintaining a safe SAR level.
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Affiliation(s)
- Randall Pursley
- Signal Processing and Instrumentation Section, Computational Bioscience and Engineering Laboratory, Office of Intramural Research, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Ayano Enomoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States; Department of Biophysical Chemistry, Nagasaki International University, Japan
| | - Haitao Wu
- Image Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jeffrey R Brender
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Thomas Pohida
- Signal Processing and Instrumentation Section, Computational Bioscience and Engineering Laboratory, Office of Intramural Research, National Institutes of Health, Bethesda, MD 20892, United States
| | - Sankaran Subramanian
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States; Indian Institute of Technology, Madras, Chennai, India
| | - Murali C Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Nallathamby Devasahayam
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
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13
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Lampp L, Rogozhnikova OY, Trukhin DV, Tormyshev VM, Bowman MK, Devasahayam N, Krishna MC, Mäder K, Imming P. A radical containing injectable in-situ-oleogel and emulgel for prolonged in-vivo oxygen measurements with CW EPR. Free Radic Biol Med 2019; 130:120-127. [PMID: 30416100 PMCID: PMC8195441 DOI: 10.1016/j.freeradbiomed.2018.10.442] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/22/2018] [Accepted: 10/25/2018] [Indexed: 02/07/2023]
Abstract
Molecular oxygen, reactive oxygen species and free radicals derived from oxygen play important roles in a broad spectrum of physiological and pathological processes. The quantitative measurement of molecular oxygen in tissues by electron paramagnetic resonance (EPR) has great potential for understanding and diagnosing a number of diseases, and for developing and guiding therapies. This requires improvements in the free radical probe systems that sense and report molecular oxygen levels in vivo. We report on the encapsulation of existing free radical probes in lipophilic gel implants: an in-situ-oleogel and an emulgel, based only on well-known, safe excipients for the incorporation of lipophilic and hydrophilic radicals, respectively. The EPR signals of encapsulated radicals were not altered compared to dissolved radicals. The high solubility of oxygen in lipophilic solvents enhanced oxygen sensitivity. The gels extended the lifetime of the radicals in tissues from tens of minutes to many days, simplifying studies with extended series of measurements. The encapsulated radicals showed a good in vivo response to changes in oxygen supply and seem to circumvent concerns from toxicity of the radical probes. These gels simplify the development of new oxygen-sensitive free radical probes for EPR oximetry by making their in vivo stability, persistence and toxicity a function of the encapsulating gel and not a set of additional requirements for the free radical probe.
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Affiliation(s)
- Lisa Lampp
- Institute of Pharmacy, Martin Luther University Halle Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany; Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Building 10, NIH, Bethesda, MD 20892-1002, USA
| | - Olga Yu Rogozhnikova
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9, Lavrentjev Ave, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia
| | - Dmitry V Trukhin
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9, Lavrentjev Ave, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia
| | - Victor M Tormyshev
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9, Lavrentjev Ave, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia
| | - Michael K Bowman
- Department of Chemistry & Biochemistry, The University of Alabama, Box 870336, Tuscaloosa, AL 35487-0336, USA
| | - Nllathamby Devasahayam
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Building 10, NIH, Bethesda, MD 20892-1002, USA
| | - Murali C Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Building 10, NIH, Bethesda, MD 20892-1002, USA
| | - Karsten Mäder
- Institute of Pharmacy, Martin Luther University Halle Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany
| | - Peter Imming
- Institute of Pharmacy, Martin Luther University Halle Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany.
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14
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Matsuo M, Kawai T, Kishimoto S, Saito K, Munasinghe J, Devasahayam N, Mitchell JB, Krishna MC. Co-imaging of the tumor oxygenation and metabolism using electron paramagnetic resonance imaging and 13-C hyperpolarized magnetic resonance imaging before and after irradiation. Oncotarget 2018; 9:25089-25100. [PMID: 29861855 PMCID: PMC5982751 DOI: 10.18632/oncotarget.25317] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/02/2018] [Indexed: 01/18/2023] Open
Abstract
To examine the relationship between local oxygen partial pressure and energy metabolism in the tumor, electron paramagnetic resonance imaging (EPRI) and magnetic resonance imaging (MRI) with hyperpolarized [1-13C] pyruvate were performed. SCCVII and HT29 solid tumors implanted in the mouse leg were imaged by EPRI using OX063, a paramagnetic probe and 13C-MRI using hyperpolarized [1-13C] pyruvate. Local partial oxygen pressure and pyruvate metabolism in the two tumor implants were examined. The effect of a single dose of 5-Gy irradiation on the pO2 and metabolism was also investigated by sequential imaging of EPRI and 13C-MRI in HT29 tumors. A phantom study using tubes filled with different concentration of [1-13C] pyruvate, [1-13C] lactate, and OX063 at different levels of oxygen confirmed the validity of this sequential imaging of EPRI and hyperpolarized 13C-MRI. In vivo studies revealed SCCVII tumor had a significantly larger hypoxic fraction (pO2 < 8 mmHg) compared to HT29 tumor. The flux of pyruvate-to-lactate conversion was also higher in SCCVII than HT29. The lactate-to-pyruvate ratio in hypoxic regions (pO2 < 8 mmHg) 24 hours after 5-Gy irradiation was significantly higher than those without irradiation (0.76 vs. 0.36) in HT29 tumor. The in vitro study showed an increase in extracellular acidification rate after irradiation. In conclusion, co-imaging of pO2 and pyruvate-to-lactate conversion kinetics successfully showed the local metabolic changes especially in hypoxic area induced by radiation therapy.
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Affiliation(s)
- Masayuki Matsuo
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.,Department of Radiology, Gifu University Graduate School of Medicine, Gifu City, Japan
| | - Tatsuya Kawai
- Radiation Oncology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Shun Kishimoto
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Keita Saito
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jeeva Munasinghe
- MRI Research Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Nallathamby Devasahayam
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - James B Mitchell
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Murali C Krishna
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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15
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Tan X, Tao S, Liu W, Rockenbauer A, Villamena FA, Zweier JL, Song Y, Liu Y. Synthesis and Characterization of the Perthiatriarylmethyl Radical and Its Dendritic Derivatives with High Sensitivity and Selectivity to Superoxide Radical. Chemistry 2018; 24:6958-6967. [DOI: 10.1002/chem.201800134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/03/2018] [Indexed: 01/13/2023]
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
| | - Shanqing Tao
- Tianjin Key Laboratory on Technologies Enabling Development of; Clinical Therapeutics and Diagnostics; School of Pharmacy; Tianjin Medical University; Tianjin 300070 P.R. China
| | - 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
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry; Hungarian Academy of Sciences and; 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 OH 43210 USA
| | - Jay L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging; The Davis Heart and Lung Research Institute; Division of Cardiovascular Medicine; Department of Internal Medicine; The Ohio State University; Columbus OH 43210 USA
| | - 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
| | - 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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16
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Matsumoto KI, Hyodo F, Mitchell JB, Krishna MC. Effect of body temperature on the pharmacokinetics of a triarylmethyl-type paramagnetic contrast agent used in EPR oximetry. Magn Reson Med 2017; 79:1212-1218. [PMID: 29143987 DOI: 10.1002/mrm.27008] [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: 08/02/2017] [Revised: 10/25/2017] [Accepted: 10/25/2017] [Indexed: 12/30/2022]
Abstract
PURPOSE Pharmacokinetics of the tri[8-carboxy-2,2,6,6-tetrakis(2-hydroxymethyl)benzo[1,2-d:4,5-d']bis(1,3)dithio-4-yl]methyl radical (Oxo63) after a single bolus and/or continuous intravenous infusion was investigated in tumor-bearing C3H mice with or without body temperature control while under anesthesia. METHOD The in vivo time course of Oxo63 in blood was measured using X-band electron paramagnetic resonance spectroscopy. Distribution of Oxo63 in normal muscle and tumor tissues was obtained using a surface coil resonator and a 700-MHz electron paramagnetic resonance spectrometer. The whole-body distribution of Oxo63 was obtained by 300-MHz continuous-wave electron paramagnetic resonance imaging. The high-resolution 300-MHz time-domain electron paramagnetic resonance imaging was also carried out to probe the distribution of Oxo63. RESULTS Urination of mice was retarded at low body temperature, causing the concentration of Oxo63 in blood to attain high levels. However, the concentration of Oxo63 in tumor tissue was lower with no control of body temperature than active body temperature control. The nonsystemized blood flow in the tumor tissues may pool Oxo63 at lower body temperature. CONCLUSIONS Pharmacokinetics of the contrast agent were found to be significantly affected by body temperature of the experimental animal, and can influence the probe distribution and the image patterns. Magn Reson Med 79:1212-1218, 2018. © Published 2017. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Ken-Ichiro Matsumoto
- Quantitative RedOx Sensing Team, Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba-shi, Japan
| | - Fuminori Hyodo
- Department of Frontier Science for Imaging, School of Medicine, Gifu University, Gifu, Japan
| | - James B Mitchell
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Murali C Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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17
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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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18
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Ueno M, Matsumoto S, Matsumoto A, Manda S, Nakanishi I, Matsumoto KI, Mitchell JB, Krishna MC, Anzai K. Effect of amifostine, a radiation-protecting drug, on oxygen concentration in tissue measured by EPR oximetry and imaging. J Clin Biochem Nutr 2017; 60:151-155. [PMID: 28584395 PMCID: PMC5453015 DOI: 10.3164/jcbn.15-130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 03/08/2016] [Indexed: 11/22/2022] Open
Abstract
Effect of amifostine, a radiation-protecting drug, on muscle tissue partial pressure of oxygen was investigated by electron paramagnetic resonance spectroscopy and imaging. When amifostine was administered intraperitoneally or intravenously to mice, the linewidth of the electron paramagnetic resonance spectra of the lithium octa-n-butoxy-substituted naphthalocyanine implanted in the mouse leg muscle decreased. Electron paramagnetic resonance oximetry using a lithium octa-n-butoxy-substituted naphthalocyanine probe and electron paramagnetic resonance oxygen mapping using a triarylmethyl radical paramagnetic probe was useful to quantify pressure of oxygen in the tissues of living mice. The result of electron paramagnetic resonance oximetric imaging showed that administration of amifostine could decrease pressure of oxygen in the muscle and also tumor tissues. This finding suggests that lowering pressure of oxygen in tissues might contribute in part to the radioprotection of amifostine.
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Affiliation(s)
- Megumi Ueno
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan
| | - Shingo Matsumoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Building 10, NIH, Bethesda, MD 20892-1002, USA
| | - Atsuko Matsumoto
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan
| | - Sushma Manda
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan
| | - Ikuo Nakanishi
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan
| | - Ken-Ichiro Matsumoto
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan
| | - James B Mitchell
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Building 10, NIH, Bethesda, MD 20892-1002, USA
| | - Murali C Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Building 10, NIH, Bethesda, MD 20892-1002, USA
| | - Kazunori Anzai
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan.,Nihon Pharmaceutical University, 10281 Komuro, Ina-machi, Kitaadachi-gun, Saitama 362-0806, Japan
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19
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Chou CC, Chandramouli GVR, Shin T, Devasahayam N, McMillan A, Babadi B, Gullapalli R, Krishna MC, Zhuo J. Accelerated electron paramagnetic resonance imaging using partial Fourier compressed sensing reconstruction. Magn Reson Imaging 2016; 37:90-99. [PMID: 27989911 DOI: 10.1016/j.mri.2016.10.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/26/2016] [Indexed: 10/20/2022]
Abstract
PURPOSE Electron paramagnetic resonance (EPR) imaging has evolved as a promising tool to provide non-invasive assessment of tissue oxygenation levels. Due to the extremely short T2 relaxation time of electrons, single point imaging (SPI) is used in EPRI, limiting achievable spatial and temporal resolution. This presents a problem when attempting to measure changes in hypoxic state. In order to capture oxygen variation in hypoxic tissues and localize cycling hypoxia regions, an accelerated EPRI imaging method with minimal loss of information is needed. METHODS We present an image acceleration technique, partial Fourier compressed sensing (PFCS), that combines compressed sensing (CS) and partial Fourier reconstruction. PFCS augments the original CS equation using conjugate symmetry information for missing measurements. To further improve image quality in order to reconstruct low-resolution EPRI images, a projection onto convex sets (POCS)-based phase map and a spherical-sampling mask are used in the reconstruction process. The PFCS technique was used in phantoms and in vivo SCC7 tumor mice to evaluate image quality and accuracy in estimating O2 concentration. RESULTS In both phantom and in vivo experiments, PFCS demonstrated the ability to reconstruct images more accurately with at least a 4-fold acceleration compared to traditional CS. Meanwhile, PFCS is able to better preserve the distinct spatial pattern in a phantom with a spatial resolution of 0.6mm. On phantoms containing Oxo63 solution with different oxygen concentrations, PFCS reconstructed linewidth maps that were discriminative of different O2 concentrations. Moreover, PFCS reconstruction of partially sampled data provided a better discrimination of hypoxic and oxygenated regions in a leg tumor compared to traditional CS reconstructed images. CONCLUSIONS EPR images with an acceleration factor of four are feasible using PFCS with reasonable assessment of tissue oxygenation. The technique can greatly enhance EPR applications and improve our understanding cycling hypoxia. Moreover this technique can be easily extended to various MRI applications.
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Affiliation(s)
- Chia-Chu Chou
- University of Maryland College Park, College Park, MD 20742, United States; Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | | | - Taehoon Shin
- Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | | | - Alan McMillan
- Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, United States
| | - Behtash Babadi
- University of Maryland College Park, College Park, MD 20742, United States
| | - Rao Gullapalli
- Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | | | - Jiachen Zhuo
- Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, United States.
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20
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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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21
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Marchand V, Levêque P, Driesschaert B, Marchand-Brynaert J, Gallez B. In vivo EPR extracellular pH-metry in tumors using a triphosphonated trityl radical. Magn Reson Med 2016; 77:2438-2443. [PMID: 27364733 DOI: 10.1002/mrm.26316] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 05/26/2016] [Accepted: 05/31/2016] [Indexed: 01/19/2023]
Abstract
PURPOSE The ability to assess the extracellular pH (pHe) is an important issue in oncology, because extracellular acidification is associated with tumor aggressiveness and resistance to cytotoxic therapies. In this study, a stable triphosphonated triarylmethyl (TPTAM) radical was qualified as a pHe electron paramagnetic resonance (EPR) molecular reporter. METHODS Calibration of hyperfine splitting as a function of pH was performed using a 1.2-GHz EPR spectrometer. Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) was used as an extracellular paramagnetic broadening agent to assess the localization of TPTAM when incubated with cells. In vivo EPR pH-metry was performed in MDA, SiHa, and TLT tumor models and in muscle. Bicarbonate therapy was used to modulate the tumor pHe. EPR measurements were compared with microelectrode readouts. RESULTS The hyperfine splitting of TPTAM was strongly pH-dependent around the pKa of the probe (pKa = 6.99). Experiments with Gd-DTPA demonstrated that TPTAM remained in the extracellular compartment. pHe was found to be more acidic in the MDA, SiHa, and TLT tumor models compared with muscle. Treatment of animals by bicarbonate induced an increase in pHe in tumors: similar variations in pHe were found when using in vivo EPR or invasive microelectrodes measurements. CONCLUSION This study demonstrates the potential usefulness of TPTAM for monitoring pHe in tumors. Magn Reson Med 77:2438-2443, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Valérie Marchand
- Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Université Catholique de Louvain, Brussels, Belgium
| | - Philippe Levêque
- Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Université Catholique de Louvain, Brussels, Belgium
| | - Benoit Driesschaert
- Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Université Catholique de Louvain, Brussels, Belgium.,Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity, Université Catholique de Louvain, Brussels, Belgium
| | - Jacqueline Marchand-Brynaert
- Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity, Université Catholique de Louvain, Brussels, Belgium
| | - Bernard Gallez
- Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Université Catholique de Louvain, Brussels, Belgium
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Abstract
Continuous-wave (CW) dynamic nuclear polarization (DNP) is now established as a method of choice to enhance the sensitivity in a variety of NMR experiments. Nevertheless, there remains a need for the development of more efficient methods to transfer polarization from electrons to nuclei. Of particular interest are pulsed DNP methods because they enable a rapid and efficient polarization transfer that, in contrast with CW DNP methods, is not attenuated at high magnetic fields. Here we report nuclear spin orientation via electron spin-locking (NOVEL) experiments using the polarizing agent trityl OX063 in glycerol/water at a temperature of 80 K and a magnetic field of 0.34 T. (1)H NMR signal enhancements up to 430 are observed, and the buildup of the local polarization occurs in a few hundred nanoseconds. Thus, NOVEL can efficiently dynamically polarize (1)H atoms in a system that is of general interest to the solid-state DNP NMR community. This is a first, important step toward the general application of pulsed DNP at higher fields.
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Epel B, Halpern HJ. In Vivo pO2 Imaging of Tumors: Oxymetry with Very Low-Frequency Electron Paramagnetic Resonance. Methods Enzymol 2015; 564:501-27. [PMID: 26477263 DOI: 10.1016/bs.mie.2015.08.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
For over a century, it has been known that tumor hypoxia, regions of a tumor with low levels of oxygenation, are important contributors to tumor resistance to radiation therapy and failure of radiation treatment of cancer. Recently, using novel pulse electron paramagnetic resonance (EPR) oxygen imaging, near absolute images of the partial pressure of oxygen (pO2) in tumors of living animals have been obtained. We discuss here the means by which EPR signals can be obtained in living tissues and tumors. We review development of EPR methods to image the pO2 in tumors and the potential for the pO2 image acquisition in human subjects.
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Affiliation(s)
- Boris Epel
- Center for Electron Paramagnetic Resonance Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois, USA
| | - Howard J Halpern
- Center for Electron Paramagnetic Resonance Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois, USA.
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24
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Decroos C, Boucher JL, Mansuy D, Xu-Li Y. Reactions of Amino Acids, Peptides, and Proteins with Oxidized Metabolites of Tris(p-carboxyltetrathiaaryl)methyl Radical EPR Probes. Chem Res Toxicol 2014; 27:627-36. [DOI: 10.1021/tx400467p] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Christophe Decroos
- Laboratoire
de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 45 rue
des Saints-Pères, 75270 Paris, France
| | - Jean-Luc Boucher
- Laboratoire
de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 45 rue
des Saints-Pères, 75270 Paris, France
| | - Daniel Mansuy
- Laboratoire
de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 45 rue
des Saints-Pères, 75270 Paris, France
| | - Yun Xu-Li
- Laboratoire
de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 45 rue
des Saints-Pères, 75270 Paris, France
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25
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Epel B, Redler G, Halpern HJ. How in vivo EPR measures and images oxygen. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 812:113-119. [PMID: 24729222 DOI: 10.1007/978-1-4939-0620-8_15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The partial pressure of oxygen (pO₂) in tissues plays an important role in the pathophysiology of many diseases and influences outcome of cancer therapy, ischemic heart and cerebrovascular disease treatments and wound healing. Over the years a suite of EPR techniques for reliable oxygen measurements has been developed. This is a mini-review of pulse EPR in vivo oxygen imaging methods that utilize soluble spin probes. Recent developments in pulse EPR imaging technology have brought an order of magnitude increase in image acquisition speed, enhancement of sensitivity and considerable improvement in the precision and accuracy of oxygen measurements.
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Affiliation(s)
- Boris Epel
- Center for EPR Imaging In Vivo Physiology, Chicago, IL, USA.,Department of Radiation Oncology, University of Chicago, Chicago, IL, USA
| | - Gage Redler
- Center for EPR Imaging In Vivo Physiology, Chicago, IL, USA.,Department of Radiation Oncology, University of Chicago, Chicago, IL, USA
| | - Howard J Halpern
- Center for EPR Imaging In Vivo Physiology, Chicago, IL, USA. .,Department of Radiation Oncology, University of Chicago, Chicago, IL, USA. .,MC1105, Department of Radiation and Cellular Oncology, University of Chicago Medical Center, 5841 S. Maryland Ave, Chicago, IL, 60637, USA.
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26
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Decroos C, Balland V, Boucher JL, Bertho G, Xu-Li Y, Mansuy D. Toward stable electron paramagnetic resonance oximetry probes: synthesis, characterization, and metabolic evaluation of new ester derivatives of a tris-(para-carboxyltetrathiaaryl)methyl (TAM) radical. Chem Res Toxicol 2013; 26:1561-9. [PMID: 24010758 DOI: 10.1021/tx400250a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tris(p-carboxyltetrathiaaryl)methyl (TAM) radicals, such as 1a ("Finland" radical), are useful EPR probes for oximetry. However, they are rapidly metabolized by liver microsomes in the presence of NADPH, with the formation of diamagnetic quinone-methide metabolites resulting from an oxidative decarboxylation of one of their carboxylate substituents. In an effort to obtain TAM derivatives potentially more metabolically stable in vivo, we have synthesized four new TAM radicals in which the carboxylate substituents of 1a have been replaced with esters groups bearing various alkyl chains designed to render them water-soluble. The new compounds were completely characterized by UV-vis and EPR spectroscopies, high resolution mass spectrometry (HRMS), and electrochemistry. Two of them were water-soluble enough to undergo detailed microsomal metabolic studies in comparison with 1a. They were found to be stable in the presence of the esterases present in rat liver microsomes and cytosol, and, contrary to 1a, stable to oxidation in the presence of NADPH-supplemented microsomes. A careful study of their possible microsomal reduction under anaerobic or aerobic conditions showed that they were more easily reduced than 1a, in agreement with their higher reduction potentials. They were reduced into the corresponding anions not only under anaerobic conditions but also in the presence of dioxygen. These anions were much more stable than that of 1a and could be characterized by UV-vis spectroscopy, MS, and at the level of their protonated product. However, they were oxidized by O₂, giving back to the starting ester radicals and catalyzing a futile cycle of O₂ reduction. Such reactions should be considered in the design of future stable EPR probes for oximetry in vivo.
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Affiliation(s)
- Christophe Decroos
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270 Paris, France
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27
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Liu Y, Song Y, De Pascali F, Liu X, Villamena FA, Zweier JL. Tetrathiatriarylmethyl radical with a single aromatic hydrogen as a highly sensitive and specific superoxide probe. Free Radic Biol Med 2012; 53:2081-2091. [PMID: 23000244 PMCID: PMC4118678 DOI: 10.1016/j.freeradbiomed.2012.09.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 09/04/2012] [Accepted: 09/13/2012] [Indexed: 01/09/2023]
Abstract
Superoxide (O(2)(•-)) plays crucial roles in normal physiology and disease; however, its measurement remains challenging because of the limited sensitivity and/or specificity of prior detection methods. We demonstrate that a tetrathiatriarylmethyl (TAM) radical with a single aromatic hydrogen (CT02-H) can serve as a highly sensitive and specific O(2)(•-) probe. CT02-H is an analogue of the fully substituted TAM radical CT-03 (Finland trityl) with an electron paramagnetic resonance (EPR) doublet signal due to its aromatic hydrogen. Owing to the neutral nature and negligible steric hindrance of the hydrogen, O(2)(•-) preferentially reacts with CT02-H at this site with production of the diamagnetic quinone methide via oxidative dehydrogenation. Upon reaction with O(2)(•-), CT02-H loses its EPR signal and this EPR signal decay can be used to quantitatively measure O(2)(•-). This is accompanied by a change in color from green to purple, with the quinone methide product exhibiting a unique UV-Vis absorbance (ε=15,900 M(-1) cm(-1)) at 540 nm, providing an additional O(2)(•-) detection method. More than five-fold higher reactivity of CT02-H for O(2)(•-) relative to CT-03 was demonstrated, with a second-order rate constant of 1.7×10(4) M(-1) s(-1) compared to 3.1×10(3) M(-1) s(-1) for CT-03. CT02-H exhibited high specificity for O(2)(•-) as evidenced by its inertness to other oxidoreductants. The O(2)(•-) generation rates detected by CT02-H from xanthine/xanthine oxidase were consistent with those measured by cytochrome c reduction but detection sensitivity was 10- to 100-fold higher. EPR detection of CT02-H enabled measurement of very low O(2)(•-) flux with a detection limit of 0.34 nM/min over 120 min. HPLC in tandem with electrochemical detection was used to quantitatively detect the stable quinone methide product and is a highly sensitive and specific method for measurement of O(2)(•-), with a sensitivity limit of ~2×10(-13) mol (10 nM with 20-μl injection volume). Based on the O(2)-dependent linewidth broadening of its EPR spectrum, CT02-H also enables simultaneous measurement of O(2) concentration and O(2)(•-) generation and was shown to provide sensitive detection of extracellular O(2)(•-) generation in endothelial cells stimulated either by menadione or with anoxia/reoxygenation. Thus, CT02-H is a unique probe that provides very high sensitivity and specificity for measurement of O(2)(•-) by either EPR or HPLC methods.
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Affiliation(s)
- Yangping Liu
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Yuguang Song
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Francesco De Pascali
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Xiaoping Liu
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Frederick A. Villamena
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- Department of Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Jay L. Zweier
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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Epel, B, Halpern H. Electron paramagnetic resonance oxygen imaging in vivo. ELECTRON PARAMAGNETIC RESONANCE 2012. [DOI: 10.1039/9781849734837-00180] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This review covers the last 15 years of the development of EPR in vivo oxygen imaging. During this time, a number of major technological and methodological advances have taken place. Narrow line width, long relaxation time, and non-toxic triaryl methyl radicals were introduced in the late 1990s. These not only improved continuous wave (CW) imaging, but also enabled the application of pulse EPR imaging to animals. Recent developments in pulse technology have brought an order of magnitude increase in image acquisition speed, enhancement of sensitivity, and considerable improvement in the precision and accuracy of oxygen measurements. Consequently, pulse methods take up a significant part of this review.
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Affiliation(s)
- Boris Epel,
- Center for EPR Imaging in vivo Physiology the University of Chicago, Department of Radiation and Cellular Oncology (MC 1105), Chicago Illinois 60637
| | - Howard Halpern
- Center for EPR Imaging in vivo Physiology the University of Chicago, Department of Radiation and Cellular Oncology (MC 1105), Chicago Illinois 60637
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Subramanian S, Devasahayam N, McMillan A, Matsumoto S, Munasinghe JP, Saito K, Mitchell JB, Chandramouli GVR, Krishna MC. Reporting of quantitative oxygen mapping in EPR imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 214:244-51. [PMID: 22188976 PMCID: PMC3278905 DOI: 10.1016/j.jmr.2011.11.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 11/16/2011] [Accepted: 11/17/2011] [Indexed: 05/30/2023]
Abstract
Oxygen maps derived from electron paramagnetic resonance spectral-spatial imaging (EPRI) are based upon the relaxivity of molecular oxygen with paramagnetic spin probes. This technique can be combined with MRI to facilitate mapping of pO(2) values in specific anatomic locations with high precision. The co-registration procedure, which matches the physical and digital dimensions of EPR and MR images, may present the pO(2) map at the higher MRI resolution, exaggerating the spatial resolution of oxygen, making it difficult to precisely distinguish hypoxic regions from normoxic regions. The latter distinction is critical in monitoring the treatment of cancer by radiation and chemotherapy, since it is well-established that hypoxic regions are three or four times more resistant to treatment compared to normoxic regions. The aim of this article is to describe pO(2) maps based on the intrinsic resolution of EPRI. A spectral parameter that affects the intrinsic spatial resolution of EPRI is the full width at half maximum (FWHM) height of the gradient-free EPR absorption line in frequency-encoded imaging. In single point imaging too, the transverse relaxation times (T(2)(∗)) limit the resolution since the signal decays by exp(-t(p)/T(2)(∗)) where the delay time after excitation pulse, t(p), is related to the resolution. Although the spin densities of two point objects may be resolved at this separation, it is inadequate to evaluate quantitative changes of pO(2) levels since the linewidths are proportionately affected by pO(2). A spatial separation of at least twice this resolution is necessary to correctly identify a change in pO(2) level. In addition, the pO(2) values are blurred by uncertainties arising from spectral dimensions. Blurring due to noise and low resolution modulates the pO(2) levels at the boundaries of hypoxic and normoxic regions resulting in higher apparent pO(2) levels in hypoxic regions. Therefore, specification of intrinsic resolution and pO(2) uncertainties are necessary to interpret digitally processed pO(2) illustrations.
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Affiliation(s)
- Sankaran Subramanian
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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Epel B, Sundramoorthy SV, Barth ED, Mailer C, Halpern HJ. Comparison of 250 MHz electron spin echo and continuous wave oxygen EPR imaging methods for in vivo applications. Med Phys 2011; 38:2045-52. [PMID: 21626937 DOI: 10.1118/1.3555297] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The authors compare two electron paramagnetic resonance imaging modalities at 250 MHz to determine advantages and disadvantages of those modalities for in vivo oxygen imaging. METHODS Electron spin echo (ESE) and continuous wave (CW) methodologies were used to obtain three-dimensional images of a narrow linewidth, water soluble, nontoxic oxygen-sensitive trityl molecule OX063 in vitro and in vivo. The authors also examined sequential images obtained from the same animal injected intravenously with trityl spin probe to determine temporal stability of methodologies. RESULTS A study of phantoms with different oxygen concentrations revealed a threefold advantage of the ESE methodology in terms of reduced imaging time and more precise oxygen resolution for samples with less than 70 torr oxygen partial pressure. Above 100 torr, CW performed better. The images produced by both methodologies showed pO2 distributions with similar mean values. However, ESE images demonstrated superior performance in low pO2 regions while missing voxels in high pO2 regions. CONCLUSIONS ESE and CW have different areas of applicability. ESE is superior for hypoxia studies in tumors.
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Affiliation(s)
- Boris Epel
- Department of Radiation and Cellular Oncology, Center for EPR Imaging In Vivo Physiology, University of Chicago, MC1105, 5841 South Maryland Avenue, Chicago, Illinois 60637, USA.
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Karogodina TY, Sergeeva SV, Stass DV. Stability And Reactivity Of Free Radicals: APhysicochemical Perspective With Biological Implications. Hemoglobin 2011; 35:262-75. [DOI: 10.3109/03630269.2011.570187] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Higaki S, Fujii H, Nagano M, Katagiri S, Takahashi Y. Measurement of pO2 in cultured mouse oocytes using electron paramagnetic resonance oximetry. ACTA ACUST UNITED AC 2010; 31:165-8. [PMID: 20460746 DOI: 10.2220/biomedres.31.165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We investigated the feasibility of measuring the partial pressure of oxygen (pO(2)) in cultured mouse oocytes by electron paramagnetic resonance (EPR) oximetry. Approximately 15 pL (0.015 microL) of Ox063, an oxygen-sensing paramagnetic material, at a concentration of 500 mM was injected into the ooplasm of mouse oocytes. When one, five and 20 oocytes were used, the sample of 20 oocytes was sufficient to yield an effective EPR spectrum for determining the pO(2). The mean pO(2) levels in oocytes cultured under tensions of 5 and 20% O(2) were 60.2 and 153.1 mmHg, respectively. The present study indicates that it is possible to utilize EPR oximetry with Ox063 for the measurement of pO(2) in cultured oocytes.
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Affiliation(s)
- Shogo Higaki
- Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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Epel B, Haney CR, Hleihel D, Wardrip C, Barth ED, Halpern HJ. Electron paramagnetic resonance oxygen imaging of a rabbit tumor using localized spin probe delivery. Med Phys 2010; 37:2553-9. [PMID: 20632567 DOI: 10.1118/1.3425787] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Application of in vivo electron paramagnetic resonance (EPR) oxygen imaging (EPROI) to tumors larger than those of mice requires development of both instrumental and medical aspects of imaging. METHODS 250 MHz EPR oxygen imaging was performed using a loop-gap resonator with a volume exceeding 100 cm3. The paramagnetic spin probe was injected directly into the femoral artery feeding the rabbit leg/tumor. RESULTS The authors present continuous wave and electron spin echo EPR oxygen images of a large size (4 cm) VX-2 tumor located on the leg of a New Zealand white rabbit. CONCLUSIONS This study demonstrates the feasibility of continuous wave and electron spin echo oxygen imaging modalities for investigation of volumes of tumor and normal tissue relevant to large animals. The injection of the spin probe directly into the artery feeding a rabbit leg will allow one to reduce, by over one order of magnitude, the amount of spin probe used as compared to whole animal i.v. injection.
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Affiliation(s)
- Boris Epel
- Department of Radiation and Cellular Oncology, The University of Chicago, MC 1105, Chicago, Illinois 60637, USA
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Yasui H, Matsumoto S, Devasahayam N, Munasinghe JP, Choudhuri R, Saito K, Subramanian S, Mitchell JB, Krishna MC. Low-field magnetic resonance imaging to visualize chronic and cycling hypoxia in tumor-bearing mice. Cancer Res 2010; 70:6427-36. [PMID: 20647318 DOI: 10.1158/0008-5472.can-10-1350] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tumors exhibit fluctuations in blood flow that influence oxygen concentrations and therapeutic resistance. To assist therapeutic planning and improve prognosis, noninvasive dynamic imaging of spatial and temporal variations in oxygen partial pressure (pO(2)) would be useful. Here, we illustrate the use of pulsed electron paramagnetic resonance imaging (EPRI) as a novel imaging method to directly monitor fluctuations in oxygen concentrations in mouse models. A common resonator platform for both EPRI and magnetic resonance imaging (MRI) provided pO(2) maps with anatomic guidance and microvessel density. Oxygen images acquired every 3 minutes for a total of 30 minutes in two different tumor types revealed that fluctuation patterns in pO(2) are dependent on tumor size and tumor type. The magnitude of fluctuations in pO(2) in SCCVII tumors ranged between 2- to 18-fold, whereas the fluctuations in HT29 xenografts were of lower magnitude. Alternating breathing cycles with air or carbogen (95% O(2) plus 5% CO(2)) distinguished higher and lower sensitivity regions, which responded to carbogen, corresponding to cycling hypoxia and chronic hypoxia, respectively. Immunohistochemical analysis suggests that the fluctuation in pO(2) correlated with pericyte density rather than vascular density in the tumor. This EPRI technique, combined with MRI, may offer a powerful clinical tool to noninvasively detect variable oxygenation in tumors.
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Affiliation(s)
- Hironobu Yasui
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892-1002, USA
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Reconstruction for time-domain in vivo EPR 3D multigradient oximetric imaging--a parallel processing perspective. Int J Biomed Imaging 2009; 2009:528639. [PMID: 19672315 PMCID: PMC2721150 DOI: 10.1155/2009/528639] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 06/01/2009] [Indexed: 01/29/2023] Open
Abstract
Three-dimensional Oximetric Electron Paramagnetic Resonance Imaging using the Single Point Imaging modality generates unpaired spin density and oxygen images that can readily distinguish between normal and tumor tissues in small animals. It is also possible with fast imaging to track the changes in tissue oxygenation in response to the oxygen content in the breathing air. However, this involves dealing with gigabytes of data for each 3D oximetric imaging experiment involving digital band pass filtering and background noise subtraction, followed by 3D Fourier reconstruction. This process is rather slow in a conventional uniprocessor system. This paper presents a parallelization framework using OpenMP runtime support and parallel MATLAB to execute such computationally intensive programs. The Intel compiler is used to develop a parallel C++ code based on OpenMP. The code is executed on four Dual-Core AMD Opteron shared memory processors, to reduce the computational burden of the filtration task significantly. The results show that the parallel code for filtration has achieved a speed up factor of 46.66 as against the equivalent serial MATLAB code. In addition, a parallel MATLAB code has been developed to perform 3D Fourier reconstruction. Speedup factors of 4.57 and 4.25 have been achieved during the reconstruction process and oximetry computation, for a data set with 23 x 23 x 23 gradient steps. The execution time has been computed for both the serial and parallel implementations using different dimensions of the data and presented for comparison. The reported system has been designed to be easily accessible even from low-cost personal computers through local internet (NIHnet). The experimental results demonstrate that the parallel computing provides a source of high computational power to obtain biophysical parameters from 3D EPR oximetric imaging, almost in real-time.
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Decroos C, Li Y, Bertho G, Frapart Y, Mansuy D, Boucher JL. Oxidative and Reductive Metabolism of Tris(p-carboxyltetrathiaaryl)methyl Radicals by Liver Microsomes. Chem Res Toxicol 2009; 22:1342-50. [DOI: 10.1021/tx9001379] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Christophe Decroos
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Yun Li
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Gildas Bertho
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Yves Frapart
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Daniel Mansuy
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Jean-Luc Boucher
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
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38
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Yan G, Peng L, Jian S, Li L, Bottle SE. Spin probes for electron paramagnetic resonance imaging. Sci Bull (Beijing) 2008. [DOI: 10.1007/s11434-008-0520-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Dhimitruka I, Bobko AA, Hadad CM, Zweier JL, Khramtsov VV. Synthesis and characterization of amino derivatives of persistent trityl radicals as dual function pH and oxygen paramagnetic probes. J Am Chem Soc 2008; 130:10780-7. [PMID: 18636723 DOI: 10.1021/ja803083z] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Triarylmethyl radicals, TAMs, are useful soluble paramagnetic probes for EPR spectroscopic and imaging applications because of their extraordinary stability in living tissues, narrow line width, high analytical resolution at micromolar concentrations and enhanced sensitivity to molecular oxygen. Recently we proposed the concept of dual function pH and oxygen TAM probes based on the incorporation of ionizable groups into the TAM structure (J. Am. Chem. Soc. 2007, 129 (23), 7240-7241). In this paper we report the synthesis of TAM derivatives containing amino groups. The synthesized TAMs combine stability with oxygen and pH sensitivity, in the range of pH from 6.8 to 9.0. To decrease the number of spectral components and improve probe solubility at physiological pH, asymmetric TAM derivatives containing both carboxyl and amino functions were synthesized. The presence of nitrogen and hydrogen atoms in direct proximity to protonatable amino groups resulted in strong pH-induced changes to the corresponding hyperfine splittings, Delta hfs approximately (300-1000) mG, comparable to the values of hfs themselves. Large pH-dependent line shifts of individual spectral components, with narrow linewidths of (160-280) mG, allow for easy discrimination between the pH effect and the observed oxygen-dependent line broadening of about (6 +/- 0.5) mG per % oxygen. The synthesized TAM derivatives represent the first dual function pH and oxygen paramagnetic probes with reasonably valuable properties for biomedical research.
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Affiliation(s)
- Ilirian Dhimitruka
- Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
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Xia S, Villamena FA, Hadad CM, Kuppusamy P, Li Y, Zhu H, Zweier JL. Reactivity of molecular oxygen with ethoxycarbonyl derivatives of tetrathiatriarylmethyl radicals. J Org Chem 2007; 71:7268-79. [PMID: 16958520 PMCID: PMC2533111 DOI: 10.1021/jo0610560] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tetrathiatriarylmethyl (TAM) radicals are commonly used as oximetry probes for electron paramagnetic resonance imaging applications. In this study, the electronic properties and the thermodynamic preferences for O2 addition to various TAM-type triarylmethyl (trityl) radicals were theoretically investigated. The radicals' stability in the presence of O2 and biological milieu was also experimentally assessed using EPR spectroscopy. Results show that H substitution on the aromatic ring affects the trityl radical's stability (tricarboxylate salt 1-CO2Na > triester 1-CO2Et > diester 2-CO2Et > monoester 3-CO2Et) and may lead to substitution reactions in cellular systems. We propose that this degradation process involves an arylperoxyl radical that can further decompose to alcohol or quinone products. This study demonstrates how computational chemistry can be used as a tool to rationalize radical stability in the redox environment of biological systems and aid in the future design of more biostable trityl radicals.
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Affiliation(s)
- Shijing Xia
- Department of Chemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Frederick A. Villamena
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | | | - Periannan Kuppusamy
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Yunbo Li
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Hong Zhu
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Jay L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
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Matsumoto KI, Subramanian S, Murugesan R, Mitchell JB, Krishna MC. Spatially resolved biologic information from in vivo EPRI, OMRI, and MRI. Antioxid Redox Signal 2007; 9:1125-41. [PMID: 17571957 DOI: 10.1089/ars.2007.1638] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
EPR spectroscopy can give biologically important information, such as tissue redox status, pO2, pH, and microviscosity, based on variation of EPR spectral characteristics (i.e., intensity, linewidth, hyperfine splitting, and spectral shape of free radical probes. EPR imaging (EPRI) can obtain 1D-3D spatial distribution of such spectral components using several combinations of magnetic field gradients. Overhauser enhanced MRI (OMRI) is a double-resonance technique of electron and nuclear spins. Because the Overhauser enhancement depends on transverse relaxation rate of the electron spin, OMRI can provide pO2 information indirectly, along with a high-resolution MR image. MRI can also indirectly detect paramagnetic behaviors of free radical contrast agents. Imaging techniques and applications relating to paramagnetic species (i.e., EPRI, OMRI, and MRI) have the potential to obtain maximally 5D information (i.e., 3D spatial + 1D spectral + 1D temporal dimensions, theoretically). To obtain suitable dimensionality, several factors, such as the EPR spectral information, spatial resolution, temporal resolution, will have to be taken into account. For this review, the EPRI, OMRI, and MRI applications for the study biological systems were evaluated for researchers to apply the method of choice and the mode of measurements to specific experimental systems.
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Affiliation(s)
- Ken-ichiro Matsumoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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Devasahayam N, Subramanian S, Murugesan R, Hyodo F, Matsumoto KI, Mitchell JB, Krishna MC. Strategies for improved temporal and spectral resolution in in vivo oximetric imaging using time-domain EPR. Magn Reson Med 2007; 57:776-83. [PMID: 17390350 DOI: 10.1002/mrm.21194] [Citation(s) in RCA: 36] [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
A radiofrequency (RF) time-domain electron paramagnetic resonance (EPR) instrument operating at 300, 600, and 750 MHz was used to image tumor hypoxia with high spatial and temporal resolution. A high-speed signal-averaging Peripheral Component Interconnect (PCI) board with flexibility in the input signal level and the number of digitized samples per free induction decay (FID) was incorporated into the receive arm of the spectrometer. This enabled effective and fast averaging of FIDs. Modification of the phase-encoding protocol, and replacement of the General Purpose Interface Bus (GPIB)-based handshake with a PCI-based D/A board for direct control of the gradient amplifier decreased the gradient settling and communication overhead times by nearly two orders of magnitude. Cyclically-ordered phase sequence (CYCLOPS) phase cycling was implemented to correct for pulse imperfections and cancel out unwanted constant signals. These upgrades considerably enhanced the performance of the imager in terms of image collection time, sensitivity, and temporal resolution. We demonstrated this by collecting a large number of 2D images successively and rapidly. The results show that it is feasible to achieve accurate, 2D pO(2) maps of tumor hypoxia with 1-mm(2) resolution and minimal artifacts using a set of multigradient images within an acceptable measuring time of about 3 s, and 3D maps can be obtained in less than 1 min.
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Affiliation(s)
- Nallathamby Devasahayam
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
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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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Bratasz A, Kulkarni AC, Kuppusamy P. A highly sensitive biocompatible spin probe for imaging of oxygen concentration in tissues. Biophys J 2007; 92:2918-25. [PMID: 17259268 PMCID: PMC1831698 DOI: 10.1529/biophysj.106.099135] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The development of an injectable probe formulation, consisting of perchlorotriphenylmethyl triester radical dissolved in hexafluorobenzene, for in vivo oximetry and imaging of oxygen concentration in tissues using electron paramagnetic resonance (EPR) imaging is reported. The probe was evaluated for its oxygen sensitivity, biostability, and distribution in a radiation-induced fibrosarcoma tumor transplanted into C3H mice. Some of the favorable features of the probe are: a single narrow EPR peak (anoxic linewidth, 41 microT), high solubility in hexafluorobenzene (>12 mM), large linewidth sensitivity to molecular oxygen ( approximately 1.8 microT/mmHg), good stability in tumor tissue (half-life: 3.3 h), absence of spin-spin broadening (up to 12 mM), and lack of power saturation effects (up to 200 mW). Three-dimensional spatial and spectral-spatial (spectroscopic) EPR imaging measurements were used to visualize the distribution of the probe, as well as to obtain spatially resolved pO(2) information in the mice tumor subjected to normoxic and hyperoxic treatments. The new probe should enable unique opportunities for measurement of the oxygen concentration in tumors using EPR methods.
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Affiliation(s)
- Anna Bratasz
- Center for Biomedical EPR Spectroscopy and Imaging, Comprehensive Cancer Center, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
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Matsumoto KI, Subramanian S, Devasahayam N, Aravalluvan T, Murugesan R, Cook JA, Mitchell JB, Krishna MC. Electron paramagnetic resonance imaging of tumor hypoxia: Enhanced spatial and temporal resolution for in vivo pO2 determination. Magn Reson Med 2006; 55:1157-63. [PMID: 16596636 DOI: 10.1002/mrm.20872] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The time-domain (TD) mode of electron paramagnetic resonance (EPR) data collection offers a means of estimating the concentration of a paramagnetic probe and the oxygen-dependent linewidth (LW) to generate pO2 maps with minimal errors. A methodology for noninvasive pO2 imaging based on the application of TD-EPR using oxygen-induced LW broadening of a triarylmethyl (TAM)-based radical is presented. The decay of pixel intensities in an image is used to estimate T2*, which is inversely proportional to pO2. Factors affecting T2* in each pixel are critically analyzed to extract the contribution of dissolved oxygen to EPR line-broadening. Suitable experimental and image-processing parameters were obtained to produce pO2 maps with minimal artifacts. Image artifacts were also minimized with the use of a novel data collection strategy using multiple gradients. Results from a phantom and in vivo imaging of tumor-bearing mice validated this novel method of noninvasive oximetry. The current imaging protocols achieve a spatial resolution of approximately 1.0 mm and a temporal resolution of approximately 9 s for 2D pO2 mapping, with a reliable oxygen resolution of approximately 1 mmHg (0.12% oxygen in gas phase). This work demonstrates that in vivo oximetry can be performed with good sensitivity, accuracy, and high spatial and temporal resolution.
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Affiliation(s)
- Ken-ichiro Matsumoto
- Radiation Biology Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-1002, USA
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