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Palma-Rojo E, Barquinero JF, Pérez-Alija J, González JR, Armengol G. Differential biological effect of low doses of ionizing radiation depending on the radiosensitivity in a cell line model. Int J Radiat Biol 2024:1-14. [PMID: 39288264 DOI: 10.1080/09553002.2024.2400514] [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: 05/09/2024] [Revised: 07/18/2024] [Accepted: 08/22/2024] [Indexed: 09/19/2024]
Abstract
PURPOSE Exposure to low doses (LD) of ionizing radiation (IR), such as the ones employed in computed tomography (CT) examination, can be associated with cancer risk. However, cancer development could depend on individual radiosensitivity. In the present study, we evaluated the differences in the response to a CT-scan radiation dose of 20 mGy in two lymphoblastoid cell lines with different radiosensitivity. MATERIALS AND METHODS Several parameters were studied: gene expression, DNA damage, and its repair, as well as cell viability, proliferation, and death. Results were compared with those after a medium dose of 500 mGy. RESULTS After 20 mGy of IR, the radiosensitive (RS) cell line showed an increase in DNA damage, and higher cell proliferation and apoptosis, whereas the radioresistant (RR) cell line was insensitive to this LD. Interestingly, the RR cell line showed a higher expression of an antioxidant gene, which could be used by the cells as a protective mechanism. After a dose of 500 mGy, both cell lines were affected by IR but with significant differences. The RS cells presented an increase in DNA damage and apoptosis, but a decrease in cell proliferation and cell viability, as well as less antioxidant response. CONCLUSIONS A differential biological effect was observed between two cell lines with different radiosensitivity, and these differences are especially interesting after a CT scan dose. If this is confirmed by further studies, one could think that individuals with radiosensitivity-related genetic variants may be more vulnerable to long-term effects of IR, potentially increasing cancer risk after LD exposure.
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Affiliation(s)
- Elia Palma-Rojo
- Unitat d'Antropologia Biològica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
| | - Joan-Francesc Barquinero
- Unitat d'Antropologia Biològica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
| | - Jaime Pérez-Alija
- Servei de Radiofísica i Radioprotecció, Hospital de la Santa Creu i Sant Pau, Barcelona, Catalonia, Spain
| | - Juan R González
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
| | - Gemma Armengol
- Unitat d'Antropologia Biològica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
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Brzóska K, Abend M, O'Brien G, Gregoire E, Port M, Badie C. Calibration curve for radiation dose estimation using FDXR gene expression biodosimetry - premises and pitfalls. Int J Radiat Biol 2024; 100:1202-1212. [PMID: 38953870 DOI: 10.1080/09553002.2024.2373751] [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: 03/08/2024] [Revised: 05/25/2024] [Accepted: 06/19/2024] [Indexed: 07/04/2024]
Abstract
PURPOSE Radiation-induced alterations in gene expression show great promise for dose reconstruction and for severity prediction of acute health effects. Among several genes explored as potential biomarkers, FDXR is widely used due to high upregulation in white blood cells following radiation exposure. Nonetheless, the absence of a standardized protocols for gene expression-based biodosimetry is a notable gap that warrants attention to enhance the accuracy, reproducibility and reliability. The objective of this study was to evaluate the sensitivity of transcriptional biodosimetry to differences in protocols used by different laboratories and establish guidelines for the calculation of calibration curve using FDXR expression data. MATERIAL AND METHODS Two sets of irradiated blood samples generated during RENEB exercise were used. The first included samples irradiated with known doses including: 0, 0.25, 0.5, 1, 2, 3 and 4 Gy. The second set consisted of three 'blind' samples irradiated with 1.8 Gy, 0.4 Gy and a sham-irradiated sample. After irradiation, samples were incubated at 37 °C over 24 h and sent to participating laboratories, where RNA isolation and FDXR expression analysis by qPCR were performed using sets of primers/probes and reference genes specific for each laboratory. Calibration curves based on FDXR expression data were generated using non-linear and linear regression and used for dose estimation of 'blind' samples. RESULTS Dose estimates for sham-irradiated sample (0.020-0.024 Gy) and sample irradiated with 0.4 Gy (0.369-0.381 Gy) showed remarkable consistency across all laboratories, closely approximating the true doses regardless variation in primers/probes and reference genes used. For sample irradiated with 1.8 Gy the dose estimates were less precise (1.198-2.011 Gy) but remained within an acceptable margin for triage within the context of high dose range. CONCLUSION Methodological differences in reference genes and primers/probes used for FDXR expression measurement do not have a significant impact on the dose estimates generated, provided that all reference genes performed as expected and the primers/probes target a similar set of transcript variants. The preferred method for constructing a calibration curve based on FDXR expression data involves employing linear regression to establish a function that describes the relationship between the logarithm of absorbed dose and FDXR ΔCt values. However, one should be careful with using non-irradiated sample data as these cannot be accurately represented on a logarithmic scale. A standard curve generated using this approach can give reliable dose estimations in a dose range from 50 mGy to 4 Gy at least.
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Affiliation(s)
- Kamil Brzóska
- Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Warsaw, Poland
| | - Michael Abend
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Grainne O'Brien
- Cancer Mechanisms and Biomarkers Group, Centre for Radiation, Chemical and Environmental Hazards, UK Health Security Agency, Oxfordshire, England
| | - Eric Gregoire
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-Santé, SERAMED, LRAcc, Fontenay-aux-Roses, France
| | - Matthias Port
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Christophe Badie
- Cancer Mechanisms and Biomarkers Group, Centre for Radiation, Chemical and Environmental Hazards, UK Health Security Agency, Oxfordshire, England
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Schüle S, Bunert F, Hackenbroch C, Beer M, Ostheim P, Stewart S, Port M, Scherthan H, Abend M. The Influence of Computed Tomography Contrast Agent on Radiation-Induced Gene Expression and Double-Strand Breaks. Radiat Res 2024; 201:396-405. [PMID: 38282002 DOI: 10.1667/rade-23-00118.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 10/14/2023] [Indexed: 01/30/2024]
Abstract
After nuclear scenarios, combined injuries of acute radiation syndrome (ARS) with, e.g., abdominal trauma, will occur and may require contrast-enhanced computed tomography (CT) scans for diagnostic purposes. Here, we investigated the effect of iodinated contrast agents on radiation-induced gene expression (GE) changes used for biodosimetry (AEN, BAX, CDKN1A, EDA2R, APOBEC3H) and for hematologic ARS severity prediction (FDXR, DDB2, WNT3, POU2AF1), and on the induction of double-strand breaks (DSBs) used for biodosimetry. Whole blood samples from 10 healthy donors (5 males, 5 females, mean age: 28 ± 2 years) were irradiated with X rays (0, 1 and 4 Gy) with and without the addition of iodinated contrast agent (0.016 ml contrast agent/ml blood) to the blood prior to the exposure. The amount of contrast agent was set to be equivalent to the blood concentration of an average patient (80 kg) during a contrast-enhanced CT scan. After irradiation, blood samples were incubated at 37°C for 20 min (DSB) and 8 h (GE, DSB). GE was measured employing quantitative real-time polymerase chain reaction. DSB foci were revealed by γH2AX + 53BP1 immunostaining and quantified automatically in >927 cells/sample. Radiation-induced differential gene expression (DGE) and DSB foci were calculated using the respective unexposed sample without supplementation of contrast agent as the reference. Neither the GE nor the number of DSB foci was significantly (P = 0.07-0.94) altered by the contrast agent application. However, for some GE and DSB comparisons with/without contrast agent, there were weakly significant differences (P = 0.03-0.04) without an inherent logic and thus are likely due to inter-individual variation. In nuclear events, the diagnostics of combined injuries can require the use of an iodinated contrast agent, which, according to our results, does not alter or influence radiation-induced GE changes and the quantity of DSB foci. Therefore, the gene expression and γH2AX focus assay can still be applied for biodosimetry and/or hematologic ARS severity prediction in such scenarios.
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Affiliation(s)
- Simone Schüle
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
- Department of Diagnostic and Interventional Radiology and Neuroradiology, German Armed Force Hospital of Ulm, Oberer Eselsberg 40, 89081 Ulm, Germany
| | - Felix Bunert
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
| | - Carsten Hackenbroch
- Department of Diagnostic and Interventional Radiology and Neuroradiology, German Armed Force Hospital of Ulm, Oberer Eselsberg 40, 89081 Ulm, Germany
- Department of Radiology, University Hospital of Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Meinrad Beer
- Department of Radiology, University Hospital of Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Patrick Ostheim
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
- Department of Radiology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg
| | - Samantha Stewart
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
| | - Matthias Port
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
| | - Harry Scherthan
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
| | - Michael Abend
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
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López-Riego M, Płódowska M, Lis-Zajęcka M, Jeziorska K, Tetela S, Węgierek-Ciuk A, Sobota D, Braziewicz J, Lundholm L, Lisowska H, Wojcik A. The DNA damage response to radiological imaging: from ROS and γH2AX foci induction to gene expression responses in vivo. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2023:10.1007/s00411-023-01033-4. [PMID: 37335333 DOI: 10.1007/s00411-023-01033-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/03/2023] [Indexed: 06/21/2023]
Abstract
Candidate ionising radiation exposure biomarkers must be validated in humans exposed in vivo. Blood from patients undergoing positron emission tomography-computed tomography scan (PET-CT) and skeletal scintigraphy (scintigraphy) was drawn before (0 h) and after (2 h) the procedure for correlation analyses of the response of selected biomarkers with radiation dose and other available patient information. FDXR, CDKN1A, BBC3, GADD45A, XPC, and MDM2 expression was determined by qRT-PCR, DNA damage (γH2AX) by flow cytometry, and reactive oxygen species (ROS) levels by flow cytometry using the 2', 7'-dichlorofluorescein diacetate test in peripheral blood mononuclear cells (PBMC). For ROS experiments, 0- and 2-h samples were additionally exposed to UVA to determine whether diagnostic irradiation conditioned the response to further oxidative insult. With some exceptions, radiological imaging induced weak γH2AX foci, ROS and gene expression fold changes, the latter with good coherence across genes within a patient. Diagnostic imaging did not influence oxidative stress in PBMC successively exposed to UVA. Correlation analyses with patient characteristics led to low correlation coefficient values. γH2AX fold change, which correlated positively with gene expression, presented a weak positive correlation with injected activity, indicating a radiation-induced subtle increase in DNA damage and subsequent activation of the DNA damage response pathway. The exposure discrimination potential of these biomarkers in the absence of control samples as frequently demanded in radiological emergencies, was assessed using raw data. These results suggest that the variability of the response in heterogeneous populations might complicate identifying individuals exposed to low radiation doses.
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Affiliation(s)
- Milagrosa López-Riego
- Centre for Radiation Protection Research, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
| | - Magdalena Płódowska
- Department of Medical Biology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Milena Lis-Zajęcka
- Department of Medical Biology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Kamila Jeziorska
- Department of Medical Biology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Sylwia Tetela
- Department of Medical Biology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Aneta Węgierek-Ciuk
- Department of Medical Biology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Daniel Sobota
- Department of Medical Physics, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Janusz Braziewicz
- Department of Medical Physics, Institute of Biology, Jan Kochanowski University, Kielce, Poland
- Department of Nuclear Medicine With Positron Emission Tomography (PET) Unit, Holy Cross Cancer Centre, Kielce, Poland
| | - Lovisa Lundholm
- Centre for Radiation Protection Research, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Halina Lisowska
- Department of Medical Biology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Andrzej Wojcik
- Centre for Radiation Protection Research, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- Department of Medical Biology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
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Schüle S, Hackenbroch C, Beer M, Muhtadi R, Hermann C, Stewart S, Schwanke D, Ostheim P, Port M, Scherthan H, Abend M. Ex-vivo dose response characterization of the recently identified EDA2R gene after low level radiation exposures and comparison with FDXR gene expression and the γH2AX focus assay. Int J Radiat Biol 2023; 99:1584-1594. [PMID: 36988552 DOI: 10.1080/09553002.2023.2194402] [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: 10/02/2022] [Accepted: 03/09/2023] [Indexed: 03/30/2023]
Abstract
OBJECTIVE Recently, promising radiation-induced EDA2R gene expression (GE) changes after low level radiation could be shown. Stimulated by that, in this study, we intended to independently validate these findings and to further characterize dose-response relationships in comparison to FDXR and the γH2AX-DNA double-strand break (DSB) focus assay, since both assays are already widely used for biodosimetry purposes. MATERIALS AND METHODS Peripheral blood samples from six healthy human donors were irradiated ex vivo (dose: ranging from 2.6 to 49.7 mGy). Subsequently, the fold-differences relative to the sham irradiated reference group were calculated. Radiation-induced changes in GE of FDXR and EDA2R were examined using the quantitative real-time polymerase-chain-reaction (qRT-PCR). DSB foci were quantified in 100 γH2AX + 53BP1 immunostained cells employing fluorescence microscopy. Examinations were performed at single time points enabling sufficient detection of both endpoints. RESULTS A significant increase in EDA2R GE relative to the unexposed control was observed in the range of 2.6 mGy (1.6-fold, p = .045) to 5.4 mGy (2.2-fold, p = .0002), whereas the copy numbers increased linearly up to 13.1-fold at 49.7 mGy. On the contrary, FDXR upregulation (2.2-fold) became significant after a 22.6 mGy exposure (p ≤ .02) and increased linearly up to 4-fold at 49.7 mGy. A significant increase in radiation-induced foci (relative to unexposed, RIF-fd) was observed after 11.3 mGy (RIF-fd: 1.5 ± 0.5, p ≤ .03), while the foci increased linearly up to 3-fold at 49.7 mGy. From this, the FDXR and RIF-fd slopes have shown comparability, while the EDA2R slope was five times higher. Nevertheless, the coefficient of variation (CV) of EDA2R was about 30% higher than for RIF-fd. CONCLUSION Higher radiation-induced EDA2R GE changes and a lower radiation detection level compared to RIF-fd and FDXR GE changes examined under optimal conditions ex vivo on human samples appear promising. Yet, our results represent just the beginning of further studies to be conducted in animal models for further time- and dose-dependent evaluation and additional examinations on radiologically examined patients to evaluate the impact of confounder, such as age, sex, social behavior, or diseases.
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Affiliation(s)
- Simone Schüle
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Carsten Hackenbroch
- Department of Diagnostic and Interventional Radiology and Neuroradiology, German Armed Force Hospital of Ulm, Ulm, Germany
- Department of Radiology, University Hospital of Ulm, Ulm, Germany
| | - Meinrad Beer
- Department of Radiology, University Hospital of Ulm, Ulm, Germany
| | - Razan Muhtadi
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Cornelius Hermann
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Samantha Stewart
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Daniel Schwanke
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Patrick Ostheim
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Matthias Port
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Harry Scherthan
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
| | - Michael Abend
- Bundeswehr Institute of Radiobiology, Affiliated to the University of Ulm, Munich, Germany
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Initial experience on abdominal photon-counting computed tomography in clinical routine: general image quality and dose exposure. Eur Radiol 2023; 33:2461-2468. [PMID: 36477938 PMCID: PMC10017564 DOI: 10.1007/s00330-022-09278-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/27/2022] [Accepted: 10/31/2022] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Photon-counting computed tomography has lately found its way into clinical routine. The new technique could offer substantial improvements regarding general image quality, image noise, and radiation dose reduction. This study evaluated the first abdominal examinations in clinical routine and compared the results to conventional computed tomography. METHODS In this single-center retrospective study, 66 patients underwent photon-counting and conventional abdominal CT. Four radiologists assessed general image quality, image noise, and image artifacts. Signal-to-noise ratio and dose properties of both techniques within the clinical application were compared. An ex vivo phantom study revealed the radiobiological impact by means of DNA double-strand break foci in peripheral blood cells by enumerating γ-H2AX+53BP1 foci. RESULTS General image quality in accordance with the Likert scale was found superior for photon-counting CT (4.74 ± 0.46 vs. 4.25 ± 0.54; p < 0.001). Signal-to-noise ratio (p < 0.001) and also dose exposure were higher for photon-counting CT (DLP: 419.2 ± 162.2 vs. 372.3 ± 236.6 mGy*cm; p = 0.0435). CT exposure resulted in significantly increased DNA damage in comparison to sham control (p < 0.001). Investigation of the average foci per cell and radiation-induced foci numbers revealed significantly elevated numbers (p = 0.004 and p < 0.0001, respectively) after photon-counting CT. CONCLUSION Photon-counting CT in abdominal examinations showed superior results regarding general image quality and signal-to-noise ratio in clinical routine. However, this seems to be traded for a significantly higher dose exposure and corresponding double-strand break frequency. Optimization of standard protocols in further clinical applications is required to find a compromise regarding picture quality and dose exposure. KEY POINTS • Photon-counting computed tomography promises to enhance the diagnostic potential of medical imaging in clinical routine. • Retrospective single-center study showed superior general image quality accompanied by higher dose exposure in initial abdominal PCCT protocols compared to state-of-the-art conventional CT. • A simultaneous ex vivo phantom study revealed correspondingly increased frequencies of DNA double-strand breaks after PCCT.
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Manils J, Marruecos L, Soler C. Exonucleases: Degrading DNA to Deal with Genome Damage, Cell Death, Inflammation and Cancer. Cells 2022; 11:2157. [PMID: 35883600 PMCID: PMC9316158 DOI: 10.3390/cells11142157] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/30/2022] [Accepted: 07/07/2022] [Indexed: 01/27/2023] Open
Abstract
Although DNA degradation might seem an unwanted event, it is essential in many cellular processes that are key to maintaining genomic stability and cell and organism homeostasis. The capacity to cut out nucleotides one at a time from the end of a DNA chain is present in enzymes called exonucleases. Exonuclease activity might come from enzymes with multiple other functions or specialized enzymes only dedicated to this function. Exonucleases are involved in central pathways of cell biology such as DNA replication, repair, and death, as well as tuning the immune response. Of note, malfunctioning of these enzymes is associated with immune disorders and cancer. In this review, we will dissect the impact of DNA degradation on the DNA damage response and its links with inflammation and cancer.
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Affiliation(s)
- Joan Manils
- Serra Húnter Programme, Immunology Unit, Department of Pathology and Experimental Therapy, School of Medicine, Universitat de Barcelona, Feixa Llarga s/n, 08907 L’Hospitalet de Llobregat, Spain;
- Immunity, Inflammation and Cancer Group, Oncobell Program, Institut d’Investigació Biomèdica de Bellvitge—IDIBELL, 08907 L’Hospitalet de Llobregat, Spain
| | - Laura Marruecos
- Breast Cancer Laboratory, Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia;
| | - Concepció Soler
- Immunity, Inflammation and Cancer Group, Oncobell Program, Institut d’Investigació Biomèdica de Bellvitge—IDIBELL, 08907 L’Hospitalet de Llobregat, Spain
- Immunology Unit, Department of Pathology and Experimental Therapy, School of Medicine, Universitat de Barcelona, 08007 Barcelona, Spain
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Becker BV, Kaatsch HL, Nestler K, Jakobi J, Schäfer B, Hantke T, Brockmann MA, Waldeck S, Port M, Ullmann R. Impact of medical imaging on the epigenome - low-dose exposure in the course of computed tomography does not induce detectable changes of DNA-methylation profiles in peripheral blood cells. Int J Radiat Biol 2021; 98:980-985. [PMID: 34779695 DOI: 10.1080/09553002.2021.2004329] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Computed tomography (CT) is a main contributor to artificial low-dose exposure. Understanding the biological effects induced by CT exposure and their dependency on the characteristics of photon spectra is essential for knowledge-driven risk assessment. In a previous gene expression study, we have identified upregulation of AEN, BAX, DDB2, EDA2R and FDXR after ex vivo exposure with single-energy CT and dual-energy CT (DECT). In this study, we focused on CT-induced changes of DNA methylation. This epigenetic modification of DNA is a central regulator of gene expression and instrumental in preserving genome integrity. Previous studies reported focal hypermethylation and global hypomethylation after exposure with doses above 100 mSv, however, the effect of low dose exposure on DNA methylation is hardly explored. MATERIALS AND METHODS DNA was isolated from peripheral blood of three healthy individuals 6 h after ex vivo exposition to single-energy (80 kV and 150 kV) and DECT (80 kV/Sn150 kV) with a calculated effective dose of 7.0 ± 0.08 mSv. The experimental setting was identical to the one used in our previous gene expression study enabling a direct comparison of gene expression results with changes of DNA methylation identified in this study. DNA methylation was analyzed by high-throughput sequencing of bisulfite-treated DNA targeted methylation sequencing. RESULTS Unsupervised hierarchical clustering based on DNA methylation profiles of all samples created three distinct clusters. Formation of these three clusters was solely determined by the origin of samples, indicating the absence of prominent irradiation-associated changes of DNA methylation. In line with this observation, inter-individual comparison of non-irradiated samples revealed 1163, 1224 and 4550 significant differentially methylated regions (DMRs), respectively, whereas the pairwise comparison of irradiated and non-irradiated samples failed to identify irradiation-induced DMRs in any of the three probands. This even applied to the genomic regions harboring AEN, BAX, DDB2, EDA2R and FDXR, the five genes known to be upregulated by CT exposure. CONCLUSIONS CT exposure with various photon spectra did not result in detectable changes of DNA methylation. However, minor effects in a subpopulation of irradiated cells cannot be ruled out. Thus, future studies with extended observation intervals are needed to investigate DNA methylation changes that are induced by indirect effects at later points of time or become detectable by clonal expansion of affected cells. Moreover, our data suggest that DNA methylation analysis is less sensitive in detecting immediate effects of low-dose irradiation when compared to gene expression analysis.
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Affiliation(s)
| | | | - Kai Nestler
- Department of Radiology and Neuroradiology, Bundeswehr Central Hospital, Koblenz, Germany
| | - Julia Jakobi
- Bundeswehr Institute of Radiobiology Affiliated to Ulm University, Munich, Germany
| | - Barbara Schäfer
- Bundeswehr Institute of Radiobiology Affiliated to Ulm University, Munich, Germany
| | - Thomas Hantke
- Bundeswehr Institute of Radiobiology Affiliated to Ulm University, Munich, Germany
| | - Marc A Brockmann
- Department of Neuroradiology, University Medical Center Mainz, Mainz, Germany
| | - Stephan Waldeck
- Department of Radiology and Neuroradiology, Bundeswehr Central Hospital, Koblenz, Germany
| | - Matthias Port
- Bundeswehr Institute of Radiobiology Affiliated to Ulm University, Munich, Germany
| | - Reinhard Ullmann
- Bundeswehr Institute of Radiobiology Affiliated to Ulm University, Munich, Germany
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9
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Ostheim P, Amundson SA, Badie C, Bazyka D, Evans AC, Ghandhi SA, Gomolka M, López Riego M, Rogan PK, Terbrueggen R, Woloschak GE, Zenhausern F, Kaatsch HL, Schüle S, Ullmann R, Port M, Abend M. Gene expression for biodosimetry and effect prediction purposes: promises, pitfalls and future directions - key session ConRad 2021. Int J Radiat Biol 2021; 98:843-854. [PMID: 34606416 DOI: 10.1080/09553002.2021.1987571] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE In a nuclear or radiological event, an early diagnostic or prognostic tool is needed to distinguish unexposed from low- and highly exposed individuals with the latter requiring early and intensive medical care. Radiation-induced gene expression (GE) changes observed within hours and days after irradiation have shown potential to serve as biomarkers for either dose reconstruction (retrospective dosimetry) or the prediction of consecutively occurring acute or chronic health effects. The advantage of GE markers lies in their capability for early (1-3 days after irradiation), high-throughput, and point-of-care (POC) diagnosis required for the prediction of the acute radiation syndrome (ARS). CONCLUSIONS As a key session of the ConRad conference in 2021, experts from different institutions were invited to provide state-of-the-art information on a range of topics including: (1) Biodosimetry: What are the current efforts to enhance the applicability of this method to perform retrospective biodosimetry? (2) Effect prediction: Can we apply radiation-induced GE changes for prediction of acute health effects as an approach, complementary to and integrating retrospective dose estimation? (3) High-throughput and point-of-care diagnostics: What are the current developments to make the GE approach applicable as a high-throughput as well as a POC diagnostic platform? (4) Low level radiation: What is the lowest dose range where GE can be used for biodosimetry purposes? (5) Methodological considerations: Different aspects of radiation-induced GE related to more detailed analysis of exons, transcripts and next-generation sequencing (NGS) were reported.
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Affiliation(s)
- Patrick Ostheim
- Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, Munich, Germany
| | - Sally A Amundson
- Center for Radiological Research, Columbia University Irving Medical Center (CUIMC), New York, NY, USA
| | - Christophe Badie
- PHE CRCE, Chilton, Didcot, Oxford, UK.,Environmental Research Group within the School of Public Health, Faculty of Medicine at Imperial College of Science, Technology and Medicine, London, UK
| | - Dimitry Bazyka
- National Research Centre for Radiation Medicine, Kyiv, Ukraine
| | - Angela C Evans
- Department of Radiation Oncology, University of California Davis, Sacramento, CA, USA
| | - Shanaz A Ghandhi
- Center for Radiological Research, Columbia University Irving Medical Center (CUIMC), New York, NY, USA
| | - Maria Gomolka
- Bundesamt für Strahlenschutz/Federal Office for Radiation Protection, Oberschleissheim, Germany
| | - Milagrosa López Riego
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Peter K Rogan
- Biochemistry, University of Western Ontario, London, Canada.,CytoGnomix Inc, London, Canada
| | | | - Gayle E Woloschak
- Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Frederic Zenhausern
- Department of Basic Medical Sciences, College of Medicine, The University of Arizona, Phoenix, AZ, USA.,Center for Applied Nanobioscience and Medicine, University of Arizona, Phoenix, AZ, USA
| | - Hanns L Kaatsch
- Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, Munich, Germany
| | - Simone Schüle
- Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, Munich, Germany
| | - Reinhard Ullmann
- Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, Munich, Germany
| | - Matthias Port
- Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, Munich, Germany
| | - Michael Abend
- Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, Munich, Germany
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