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Carrothers E, Appleby M, Lai V, Kozbenko T, Alomar D, Smith BJ, Hamada N, Hinton P, Ainsbury EA, Hocking R, Yauk C, Wilkins RC, Chauhan V. AOP report: Development of an adverse outcome pathway for deposition of energy leading to cataracts. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2024. [PMID: 38644659 DOI: 10.1002/em.22594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/23/2024]
Abstract
Cataracts are one of the leading causes of blindness, with an estimated 95 million people affected worldwide. A hallmark of cataract development is lens opacification, typically associated not only with aging but also radiation exposure as encountered by interventional radiologists and astronauts during the long-term space mission. To better understand radiation-induced cataracts, the adverse outcome pathway (AOP) framework was used to structure and evaluate knowledge across biological levels of organization (e.g., macromolecular, cell, tissue, organ, organism and population). AOPs identify a sequence of key events (KEs) causally connected by key event relationships (KERs) beginning with a molecular initiating event to an adverse outcome (AO) of relevance to regulatory decision-making. To construct the cataract AO and retrieve evidence to support it, a scoping review methodology was used to filter, screen, and review studies based on the modified Bradford Hill criteria. Eight KEs were identified that were moderately supported by empirical evidence (e.g., dose-, time-, incidence-concordance) across the adjacent (directly linked) relationships using well-established endpoints. Over half of the evidence to justify the KER linkages was derived from the evidence stream of biological plausibility. Early KEs of oxidative stress and protein modifications had strong linkages to downstream KEs and could be the focus of countermeasure development. Several identified knowledge gaps and inconsistencies related to the quantitative understanding of KERs which could be the basis of future research, most notably directed to experiments in the range of low or moderate doses and dose-rates, relevant to radiation workers and other occupational exposures.
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Affiliation(s)
- Emma Carrothers
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Meghan Appleby
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Vita Lai
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Tatiana Kozbenko
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Dalya Alomar
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Benjamin J Smith
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Nobuyuki Hamada
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Chiba, Japan
| | - Patricia Hinton
- Defense Research & Development Canada, Canadian Forces Environmental Medicine Establishment, Toronto, Ontario, Canada
| | - Elizabeth A Ainsbury
- Radiation, Chemical and Environmental Hazards Division, UK Health Security Agency, Birmingham, UK
- Environmental Research Group within the School of Public Health, Faculty of Medicine at Imperial College of Science, Technology and Medicine, London, UK
| | - Robyn Hocking
- Learning and Knowledge and Library Services, Health Canada, Ottawa, Ontario, Canada
| | - Carole Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Ruth C Wilkins
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Vinita Chauhan
- Consumer and Clinical Radiation Protection Bureau, Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, Ontario, Canada
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Udroiu I, Sgura A. X-ray and DNA Damage: Limitations of the Dose as a Parameter for In Vitro Studies. Int J Mol Sci 2023; 24:16643. [PMID: 38068965 PMCID: PMC10706214 DOI: 10.3390/ijms242316643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
A century of studies has demonstrated that the magnitude of a radiation dose determines the extent of its biological effect. However, different types of radiation show different levels of effectiveness. Although all types of X-rays are usually considered to be equivalent, several authors have demonstrated an inverse relationship between photon energy and the biological effectiveness of the X-ray. Nonetheless, the differences among 50-100 keV X-rays are usually considered absent. However, comparing different types of X-rays with different energies is not easy since they are often used with different dose rates, and the latter can be a confounding factor. We compared the biological effectiveness of X-rays with different photon energies but with the same dose rate. Moreover, we also studied X-ray with different dose rates but the same photon energy. Biological effectiveness was assessed measuring DNA damage and cell survival. We confirmed that both the dose rate and photon energy influence the effectiveness of an X-ray. Moreover, we observed that differences in the 50-100 keV range are detectable after controlling for dose-rate variations. Our results, confirming those of previous studies in a more consistent way (and accompanied by hypotheses on the importance of the number of incident photons), underline the limitations of using the dose as the sole parameter for in vitro studies.
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Affiliation(s)
- Ion Udroiu
- Department of Sciences, Università Roma Tre, Viale G. Marconi 446, 00146 Rome, Italy;
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Abstract
PURPOSE Cataract (opacification of the ocular lens) is a typical tissue reaction (deterministic effect) following ionizing radiation exposure, for which prevention dose limits have been recommended in the radiation protection system. Manifestations of radiation cataracts can vary among individuals, but such potential individual responses remain uncharacterized. Here we review relevant literature and discuss implications for radiation protection. This review assesses evidence for significant modification of radiation-induced cataractogenesis by age at exposure, sex and genetic factors based on current scientific literature. CONCLUSIONS In addition to obvious physical factors (e.g. dose, dose rate, radiation quality, irradiation volume), potential factors modifying individual responses for radiation cataracts include sex, age and genetics, with comorbidity and coexposures also having important roles. There are indications and preliminary data identifying such potential modifiers of radiation cataract incidence or risk, although no firm conclusions can yet be drawn. Further studies and a consensus on the evidence are needed to gain deeper insights into factors determining individual responses regarding radiation cataracts and the implications for radiation protection.
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Affiliation(s)
- Stephen G R Barnard
- UK Health Security Agency (UKHSA), Radiation, Chemical and Environmental Hazards Division (RCEHD), Didcot, UK
| | - Nobuyuki Hamada
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo, Japan
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Staff eye lens dose in interventional radiology and cardiology in Finland. Phys Med 2022; 98:1-7. [DOI: 10.1016/j.ejmp.2022.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/29/2022] [Accepted: 04/09/2022] [Indexed: 11/20/2022] Open
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Iori M, Isolan L, Piergallini L, Chendi A, Lasagni L, Cucchi G, Bertolini M, Fioroni F, Piccagli V, Moramarco A, Romano MG, Fontana L, Strigari L, D'Alessio D, Bruzzaniti V, Sgura A, Udroiu I, Rosi A, Grande S, Palma A, Giliberti C, Sumini M. How direct measurements of worker eyes with a Scheimpflug camera can affect lensdose coefficients in interventional radiology. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:689-706. [PMID: 33827064 DOI: 10.1088/1361-6498/abf56f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
The 2013/59/Euratom Directive reduced the occupational exposure limits for the lens. Since it has become crucial to estimate the dose absorbed by the lens, we have studied the individual variability of exposed workers' ocular conformations with respect to the data estimated from their personal dosimetry. The anterior eye conformations of 45 exposed workers were acquired using Scheimpflug imaging and classified according to their sight conditions (emmetropia, myopia or hypermetropia). Three eye models were computed, with two lens reconstructions, and implemented in an interventional radiology scenario using Monte Carlo code. The models were dosimetrically analysed by simulating setup A, a theoretical monoenergetic and isotropic photon source (10-150 keV) and setup B, a more realistic interventional setting with an angiographic x-ray unit (50, 75, 100 kV peak). Scheimpflug imaging provided an average anterior chamber depth of (6.4 ± 0.5) mm and a lens depth of (3.9 ± 0.3) mm, together with a reconstructed equatorial lens length of (7.1-10.1) mm. Using these data for model reconstruction, dose coefficients (DCs) were simulated for all ocular structures. Regardless of the eye model used, the DCs showed a similar trend with radiation energy, which highlighted that for the same energy and setup, no significant dependence on ocular morphology and workers' visual conditions was observed. The maximum difference obtained did not exceed 1% for all eye models or structures analysed. Therefore, the individual variabilities of worker ocular anatomy do not require any additional correction, compared to the personal dosimetry data measured with a dedicated lens dosimeter. To estimate the dose absorbed by the other eye structures, it is, instead, essential to know the spectrum of the source that has generated the irradiation, since there are differences between monoenergetic sources and more realistic angiographic units.
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Affiliation(s)
- Mauro Iori
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Lorenzo Isolan
- University of Bologna, Industrial Engineering Department, Montecuccolino Laboratory, Bologna, Italy
- Interdepartmental Center 'L. Galvani' CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
- INFN, Bologna, Italy
| | - Lorenzo Piergallini
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Agnese Chendi
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
- Medical Physics, University of Bologna, Bologna, Italy
| | - Lorenzo Lasagni
- Postgraduate school in Medical Physics, University of Firenze, Firenze, Italy
| | - Giorgio Cucchi
- University of Bologna, Industrial Engineering Department, Montecuccolino Laboratory, Bologna, Italy
- Interdepartmental Center 'L. Galvani' CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
| | - Marco Bertolini
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Federica Fioroni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Vando Piccagli
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Antonio Moramarco
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Maria Grazia Romano
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Luigi Fontana
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Lidia Strigari
- Department of Medical Physics, St. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Daniela D'Alessio
- Laboratory of Medical Physics and Expert Systems, Regina Elena Cancer Institute IRCCS, Rome, Italy
| | - Vicente Bruzzaniti
- Laboratory of Medical Physics and Expert Systems, Regina Elena Cancer Institute IRCCS, Rome, Italy
| | - Antonella Sgura
- Department of Science, University of Rome 'Roma Tre', Rome, Italy
| | - Ion Udroiu
- Department of Science, University of Rome 'Roma Tre', Rome, Italy
| | - Antonella Rosi
- Istituto Superiore di Sanità, Centro Nazionale Tecnologie Innovative in Sanità Pubblica, Rome, Italy
| | - Sveva Grande
- Istituto Superiore di Sanità, Centro Nazionale Tecnologie Innovative in Sanità Pubblica, Rome, Italy
| | - Alessandra Palma
- Istituto Superiore di Sanità, Centro Nazionale Tecnologie Innovative in Sanità Pubblica, Rome, Italy
| | - Claudia Giliberti
- Inail-Dipartimento Innovazioni Tecnologiche e Sicurezza degli Impianti, Prodotti ed Insediamenti Antropici, Rome, Italy
| | - Marco Sumini
- University of Bologna, Industrial Engineering Department, Montecuccolino Laboratory, Bologna, Italy
- Interdepartmental Center 'L. Galvani' CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
- INFN, Bologna, Italy
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Ahmadi M, Barnard S, Ainsbury E, Kadhim M. Early Responses to Low-Dose Ionizing Radiation in Cellular Lens Epithelial Models. Radiat Res 2021; 197:78-91. [PMID: 34324666 DOI: 10.1667/rade-20-00284.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 07/06/2021] [Indexed: 11/03/2022]
Abstract
Cataract is the leading cause of visual impairment which can result in blindness. Cataract formation has been associated with radiation exposure; however, the mechanistic understanding of this phenomenon is still lacking. The goal of this study was to investigate mechanisms of cataract induction in isolated lens epithelial cells (LEC) exposed to ionizing radiation. Human LECs from different genetic backgrounds (SV40 immortalized HLE-B3 and primary HLEC cells) were exposed to varying doses of 137Cs gamma rays (0, 0.1, 0.25 and 0.5 Gy), at low (0.065 Gy/min) and higher (0.3 Gy/min) dose rates. Different assays were used to measure LEC response for, e.g., viability, oxidative stress, DNA damage studies, senescence and changes to telomere length/telomerase activity at two time points (1 h and 24 h, or 24 h and 15 days, depending on the type of assay and expected response time). The viability of cells decreased in a dose-dependent manner within 24 h of irradiation. Measurement of reactive oxygen species showed an increase at 1 h postirradiation, which was alleviated within 24 h. This was consistent with DNA damage results showing high DNA damage after 1 h postirradiation which reduced significantly (but not completely) within 24 h. Induction of senescence was also observed 15 days postirradiation, but this was not attributed to telomere erosion or telomerase activity reduction. Overall, these findings provide a mechanistic understanding of low-dose radiation-induced cataractogenesis which will ultimately help to inform judgements on the magnitude of risk and improve existing radiation protection procedures.
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Affiliation(s)
- Maryam Ahmadi
- Genomic Instability and Cell Communication Research Group, Department of Biological and Medical Science, Oxford Brookes University, Oxford, United Kingdom.,Kidney Genetics Group, Academic Unit of Nephrology, The Medical School, Royal Hallamshire Hospital, Sheffield, United Kingdom
| | - Stephen Barnard
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Oxford, United Kingdom
| | - Elizabeth Ainsbury
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Oxford, United Kingdom
| | - Munira Kadhim
- Genomic Instability and Cell Communication Research Group, Department of Biological and Medical Science, Oxford Brookes University, Oxford, United Kingdom
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