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Swartz HM, Flood AB. Re-examining What the Results of "a Measurement of Oxygen Level in Tissues" Really Mean. Mol Imaging Biol 2024; 26:391-402. [PMID: 38177616 DOI: 10.1007/s11307-023-01887-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024]
Abstract
Within this special issue, many eminent investigators report on measurements of oxygen (O2) levels in tissues. Given the complexities of spatial and temporal heterogeneities of O2 in tissues and its many sources, this commentary draws attention to what such measurements do and do not actually assess regarding O2 levels in tissues. Given this limitation, it also discusses how these results can be used most effectively. To provide a convenient mechanism to discuss these issues more fully, this analysis focuses on measurements using EPR oximetry, but these considerations apply to all other techniques. The nature of the delivery of O2 to tissues and the mechanisms by which O2 is consumed necessarily result in very different levels of O2 within the volume of each voxel of a measurement. Better spatial resolution cannot fully resolve the problem because the variations include O2 gradients within each cell. Improved resolution of the time-dependent variation in O2 is also very challenging because O2 levels within tissues can have fluctuations of O2 levels in the range of milliseconds, while most methods require longer times to acquire the data from each voxel. Based on these issues, we argue that the values obtained inevitably are complex aggregates of averages of O2 levels across space and time in the tissue. These complexities arise from the complex physiology of tissues and are compounded by the limitations of the technique and its ability to acquire data. However, one often can obtain very meaningful and useful results if these complexities and limitations are taken into account. We illustrate this, using results obtained with in vivo EPR oximetry, especially utilizing its capacity to make repeated measurements to follow changes in O2 levels that occur with interventions and/or over time.
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Affiliation(s)
- Harold M Swartz
- Dept. of Radiology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Clin-EPR, LLC, Lyme, NH, USA
| | - Ann Barry Flood
- Dept. of Radiology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA.
- Clin-EPR, LLC, Lyme, NH, USA.
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Krzykawska-Serda M, Szczygieł D, Gaweł S, Drzał A, Szczygieł M, Kmieć MM, Mackiewicz A, Kieda C, Elas M. Oxygen therapeutic window induced by myo-inositol trispyrophosphate (ITPP)-Local pO2 study in murine tumors. PLoS One 2023; 18:e0285318. [PMID: 37167239 PMCID: PMC10174508 DOI: 10.1371/journal.pone.0285318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 04/19/2023] [Indexed: 05/13/2023] Open
Abstract
Hypoxia, an inevitable feature of locally advanced solid tumors, has been known as an adverse prognostic factor, a driver of an aggressive phenotype, and an unfavorable factor in therapies. Myo-inositol trispyrophosphate (ITPP) is a hemoglobin modifier known to both increase O2 release and normalize microvasculature. Our goal was to measure the tumor oxygen partial pressure dynamic changes and timing of the therapeutic window after ITPP systemic administration. Two syngeneic tumor models in mice, B16 melanoma and 4T1 breast carcinoma, were used, with varying ITPP dose schedules. Tissue oxygenation level was measured over several days in situ in live animals by Electron Paramagnetic Resonance oximetry with implanted OxyChip used as a constant sensor of the local pO2 value. Both B16 and 4T1 tumors became more normoxic after ITPP treatment, with pO2 levels elevated by 10-20 mm Hg compared to the control. The increase in pO2 was either transient or sustained, and the underlying mechanism relied on shifting hypoxic tumor areas to normoxia. The effect depended on ITPP delivery intervals regarding the tumor type and growth rate. Moreover, hypoxic tumors before treatment responded better than normoxic ones. In conclusion, the ITPP-generated oxygen therapeutic window may be valuable for anti-tumor therapies requiring oxygen, such as radio-, photo- or immunotherapy. Furthermore, such a combinatory treatment can be especially beneficial for hypoxic tumors.
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Affiliation(s)
- Martyna Krzykawska-Serda
- Faculty of Biochemistry, Biophysics and Biotechnology, Department of Biophysics and Cancer Biology, Jagiellonian University, Kraków, Poland
| | - Dariusz Szczygieł
- Faculty of Biochemistry, Biophysics and Biotechnology, Department of Biophysics and Cancer Biology, Jagiellonian University, Kraków, Poland
| | - Szymon Gaweł
- Faculty of Biochemistry, Biophysics and Biotechnology, Department of Biophysics and Cancer Biology, Jagiellonian University, Kraków, Poland
| | - Agnieszka Drzał
- Faculty of Biochemistry, Biophysics and Biotechnology, Department of Biophysics and Cancer Biology, Jagiellonian University, Kraków, Poland
| | - Małgorzata Szczygieł
- Faculty of Biochemistry, Biophysics and Biotechnology, Department of Biophysics and Cancer Biology, Jagiellonian University, Kraków, Poland
| | - Maciej M Kmieć
- Department of Radiology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Andrzej Mackiewicz
- Department of Cancer Immunology, Greater Poland Cancer Centre, Poznan University of Medical Sciences, Chair of Medical Biotechnology, Poznan, Poland
| | - Claudine Kieda
- Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine -National Research Institute, Warsaw, Poland
- Center for Molecular Biophysics UPR 4301 CNRS, 45071, Orleans, France
- Department of Oncology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Martyna Elas
- Faculty of Biochemistry, Biophysics and Biotechnology, Department of Biophysics and Cancer Biology, Jagiellonian University, Kraków, Poland
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Swartz HM, Hoopes PJ, Gladstone DJ, Demidov V, Vaupel P, Flood AB, Williams BB, Zhang R, Pogue BW. A Radiation Biological Analysis of the Oxygen Effect as a Possible Mechanism in FLASH. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1395:315-321. [PMID: 36527655 PMCID: PMC10653672 DOI: 10.1007/978-3-031-14190-4_51] [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] [Indexed: 12/23/2022]
Abstract
The delivery of radiation at an ultra-high dose rate (FLASH) is an important new approach to radiotherapy (RT) that appears to be able to improve the therapeutic ratio by diminishing damage to normal tissues. While the mechanisms by which FLASH improves outcomes have not been established, a role involving molecular oxygen (O2) is frequently mentioned. In order to effectively determine if the protective effect of FLASH RT occurs via a differential direct depletion of O2 (compared to conventional radiation), it is essential to consider the known role of O2 in modifying the response of cells and tissues to ionising radiation (known as 'the oxygen effect'). Considerations include: (1) The pertinent reaction involves an unstable intermediate of radiation-damaged DNA, which either undergoes chemical repair to restore the DNA or reacts with O2, resulting in an unrepairable lesion in the DNA, (2) These reactions occur in the nuclear DNA, which can be used to estimate the distance needed for O2 to diffuse through the cell to reach the intermediates, (3) The longest lifetime that the reactive site of the DNA is available to react with O2 is 1-10 μsec, (4) Using these lifetime estimates and known diffusion rates in different cell media, the maximal distance that O2 could travel in the cytosol to reach the site of the DNA (i.e., the nucleus) in time to react are 60-185 nm. This calculation defines the volume of oxygen that is pertinent for the direct oxygen effect, (5) Therefore, direct measurements of oxygen to determine if FLASH RT operates through differential radiochemical depletion of oxygen will require the ability to measure oxygen selectively in a sphere of <200 nm, with a time resolution of the duration of the delivery of FLASH, (6) It also is possible that alterations of oxygen levels by FLASH could occur more indirectly by affecting oxygen-dependent cell signalling and/or cellular repair.
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Affiliation(s)
- Harold M Swartz
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA.
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Centre, Lebanon, NH, USA.
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.
| | - P Jack Hoopes
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Centre, Lebanon, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - David J Gladstone
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Centre, Lebanon, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | | | - Peter Vaupel
- Department of Radiation Oncology, University Medical Center, Freiburg, Germany
| | - Ann Barry Flood
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Centre, Lebanon, NH, USA
| | - Benjamin B Williams
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Centre, Lebanon, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Rongxiao Zhang
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Centre, Lebanon, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Brian W Pogue
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Centre, Lebanon, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
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Oxygen levels are key to understanding "Anaerobic" protozoan pathogens with micro-aerophilic lifestyles. Adv Microb Physiol 2021; 79:163-240. [PMID: 34836611 DOI: 10.1016/bs.ampbs.2021.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Publications abound on the physiology, biochemistry and molecular biology of "anaerobic" protozoal parasites as usually grown under "anaerobic" culture conditions. The media routinely used are poised at low redox potentials using techniques that remove O2 to "undetectable" levels in sealed containers. However there is growing understanding that these culture conditions do not faithfully resemble the O2 environments these organisms inhabit. Here we review for protists lacking oxidative energy metabolism, the oxygen cascade from atmospheric to intracellular concentrations and relevant methods of measurements of O2, some well-studied parasitic or symbiotic protozoan lifestyles, their homeodynamic metabolic and redox balances, organism-drug-oxygen interactions, and the present and future prospects for improved drugs and treatment regimes.
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What Is the Meaning of an Oxygen Measurement? : Analysis of Methods Purporting to Measure Oxygen in Targeted Tissues. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1269:301-308. [PMID: 33966234 DOI: 10.1007/978-3-030-48238-1_48] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Clinical measurements of O2 in tissues will inevitably provide data that are at best aggregated and will not reflect the inherent heterogeneity of O2 in tissues over space and time. Additionally, the nature of all existing techniques to measure O2 results in complex sampling of the volume that is sensed by the technique. By recognizing these potential limitations of the measures, one can focus on the very important and useful information that can be obtained from these techniques, especially data about factors that can change levels of O2 and then exploit these changes diagnostically and therapeutically. The clinical utility of such data ultimately needs to be verified by careful studies of outcomes related to the measured changes in levels of O2.
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Swartz HM, Flood AB, Schaner PE, Halpern H, Williams BB, Pogue BW, Gallez B, Vaupel P. How best to interpret measures of levels of oxygen in tissues to make them effective clinical tools for care of patients with cancer and other oxygen-dependent pathologies. Physiol Rep 2020; 8:e14541. [PMID: 32786045 PMCID: PMC7422807 DOI: 10.14814/phy2.14541] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 02/07/2023] Open
Abstract
It is well understood that the level of molecular oxygen (O2 ) in tissue is a very important factor impacting both physiology and pathological processes as well as responsiveness to some treatments. Data on O2 in tissue could be effectively utilized to enhance precision medicine. However, the nature of the data that can be obtained using existing clinically applicable techniques is often misunderstood, and this can confound the effective use of the information. Attempts to make clinical measurements of O2 in tissues will inevitably provide data that are aggregated over time and space and therefore will not fully represent the inherent heterogeneity of O2 in tissues. Additionally, the nature of existing techniques to measure O2 may result in uneven sampling of the volume of interest and therefore may not provide accurate information on the "average" O2 in the measured volume. By recognizing the potential limitations of the O2 measurements, one can focus on the important and useful information that can be obtained from these techniques. The most valuable clinical characterizations of oxygen are likely to be derived from a series of measurements that provide data about factors that can change levels of O2 , which then can be exploited both diagnostically and therapeutically. The clinical utility of such data ultimately needs to be verified by careful studies of outcomes related to the measured changes in levels of O2 .
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Affiliation(s)
- Harold M Swartz
- Department of Radiology, Dartmouth Medical School, Hanover, NH, USA
- Department of Medicine, Section of Radiation Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Ann Barry Flood
- Department of Radiology, Dartmouth Medical School, Hanover, NH, USA
| | - Philip E Schaner
- Department of Medicine, Section of Radiation Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Howard Halpern
- Department Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA
| | - Benjamin B Williams
- Department of Radiology, Dartmouth Medical School, Hanover, NH, USA
- Department of Medicine, Section of Radiation Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Department of Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Bernard Gallez
- Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Peter Vaupel
- Department Radiation Oncology, University Medical Center, University of Freiburg, Freiburg, Germany
- German Cancer Center Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Waller J, Onderdonk B, Flood A, Swartz H, Shah J, Shah A, Aydogan B, Halpern H, Hasan Y. The clinical utility of imaging methods used to measure hypoxia in cervical cancer. Br J Radiol 2020; 93:20190640. [PMID: 32286849 PMCID: PMC7336054 DOI: 10.1259/bjr.20190640] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 03/18/2020] [Accepted: 04/07/2020] [Indexed: 12/13/2022] Open
Abstract
While it is well-established that hypoxia is a major factor that affects clinical outcomes in cervical cancer, widespread usage of clinically available methods to detect and evaluate hypoxia during the course of treatment have not been established. This review compares these methods, summarizes their strengths and weaknesses, and assesses the pathways for their useful employment to alter clinical practice. We conducted a search on PubMed for literature pertaining to imaging hypoxic cervical cancer, and implemented keywords related to oxygen measurement tools to improve the relevance of the search results.Oxygenation level-dependent applications of MRI have demonstrated hypoxia-induced radioresistance, and changes in cervix tumor oxygenation from hyperoxic therapy.The hypoxic areas within tumors can be indirectly identified in dynamic contrast-enhanced images, where they generally display low signal enhancement, and diffusion-weighted images, which demonstrates areas of restricted diffusion (which correlates with hypoxia). Positron emmision tomography, used independently and with other imaging modalities, has demonstrated utility in imaging hypoxia through tracers specific for low oxygen levels, like Cu-ATSM tracers and nitroimidazoles. Detecting hypoxia in the tumors of patients diagnosed with cervical cancer via medical imaging and non-imaging tools like electron paramagnetic resonance oximetry can be utilized clinically, such as for guiding radiation and post-treatment surveillance, for a more personalized approach to treatment. The merits of these methods warrant further investigation via comparative effectiveness research and large clinical trials into their clinical applications.
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Affiliation(s)
- Joseph Waller
- Drexel College of Medicine, 2900 W Queen Ln, PA 19129, United States
| | - Benjamin Onderdonk
- Department of Radiation and Cellular Oncology, The University of Chicago, 5758 S Maryland Ave, IL 60637, United States
| | - Ann Flood
- Department of Radiology, Dartmouth Geisel School of Medicine, 1 Rope Ferry Rd, NH 03755, United States
| | - Harold Swartz
- Department of Radiology, Dartmouth Geisel School of Medicine, 1 Rope Ferry Rd, NH 03755, United States
| | - Jaffer Shah
- Drexel College of Medicine, 2900 W Queen Ln, PA 19129, United States
| | - Asghar Shah
- Brown University, Providence, RI 02912, United States
| | - Bulent Aydogan
- Department of Radiation and Cellular Oncology, The University of Chicago, 5758 S Maryland Ave, IL 60637, United States
| | - Howard Halpern
- Department of Radiation and Cellular Oncology, The University of Chicago, 5758 S Maryland Ave, IL 60637, United States
| | - Yasmin Hasan
- Department of Radiation and Cellular Oncology, The University of Chicago, 5758 S Maryland Ave, IL 60637, United States
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Clinical and Statistical Considerations when Assessing Oxygen Levels in Tumors: Illustrative Results from Clinical EPR Oximetry Studies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1232:155-168. [PMID: 31893406 DOI: 10.1007/978-3-030-34461-0_20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The success of treatment for malignancies, especially those undergoing radiation therapy or chemotherapy, has long been recognized to depend on the degree of hypoxia in the tumor. In addition to the prognostic value of knowing the tumor's initial level of hypoxia, assessing the tumor oxygenation during standard therapy or oxygen-related treatments (such as breathing oxygen-enriched gas mixtures or taking drugs that can increase oxygen supply to tissues) can provide valuable data to improve the efficacy of treatments. A series of early clinical studies of tumors in humans are ongoing at Dartmouth and Emory using electron paramagnetic resonance (EPR) oximetry to assess tumor oxygenation, initially and over time during either natural disease progression or treatment. This approach has the potential for reaching the long-sought goal of enhancing the effectiveness of cancer therapy. In order to effectively reach this goal, we consider the validity of the practical and statistical assumptions when interpreting the measurements made in vivo for patients undergoing treatment for cancer.
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