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Wang E, Shuryak I, Brenner DJ. A competing risks machine learning study of neutron dose, fractionation, age, and sex effects on mortality in 21,000 mice. Sci Rep 2024; 14:17974. [PMID: 39095647 PMCID: PMC11297256 DOI: 10.1038/s41598-024-68717-9] [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: 03/25/2024] [Accepted: 07/25/2024] [Indexed: 08/04/2024] Open
Abstract
This study explores the impact of densely-ionizing radiation on non-cancer and cancer diseases, focusing on dose, fractionation, age, and sex effects. Using historical mortality data from approximately 21,000 mice exposed to fission neutrons, we employed random survival forest (RSF), a powerful machine learning algorithm accommodating nonlinear dependencies and interactions, treating cancer and non-cancer outcomes as competing risks. Unlike traditional parametric models, RSF avoids strict assumptions and captures complex data relationships through decision tree ensembles. SHAP (SHapley Additive exPlanations) values and variable importance scores were employed for interpretation. The findings revealed clear dose-response trends, with cancer being the predominant cause of mortality. SHAP value dose-response shapes differed, showing saturation for cancer hazard at high doses (> 2 Gy) and a more linear pattern at lower doses. Non-cancer responses remained more linear throughout the entire dose range. There was a potential inverse dose rate effect for cancer, while the evidence for non-cancer was less conclusive. Sex and age effects were less pronounced. This investigation, utilizing machine learning, enhances our understanding of the patterns of non-cancer and cancer mortality induced by densely-ionizing radiations, emphasizing the importance of such approaches in radiation research, including space travel and radioprotection.
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Affiliation(s)
- Eric Wang
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th street, VC-11, New York, NY, 10032, USA.
| | - Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th street, VC-11, New York, NY, 10032, USA
| | - David J Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th street, VC-11, New York, NY, 10032, USA
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Rudolf AM, Hood WR. Mitochondrial stress in the spaceflight environment. Mitochondrion 2024; 76:101855. [PMID: 38403094 DOI: 10.1016/j.mito.2024.101855] [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: 07/08/2023] [Revised: 02/12/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Space is a challenging environment that deregulates individual homeostasis. The main external hazards associated with spaceflight include ionizing space radiation, microgravity, isolation and confinement, distance from Earth, and hostile environment. Characterizing the biological responses to spaceflight environment is essential to validate the health risks, and to develop effective protection strategies. Mitochondria energetics is a key mechanism underpinning many physiological, ecological and evolutionary processes. Moreover, mitochondrial stress can be considered one of the fundamental features of space travel. So, we attempt to synthesize key information regarding the extensive effects of spaceflight on mitochondria. In summary, mitochondria are affected by all of the five main hazards of spaceflight at multiple levels, including their morphology, respiratory function, protein, and genetics, in various tissues and organ systems. We emphasize that investigating mitochondrial biology in spaceflight conditions should become the central focus of research on the impacts of spaceflight on human health, as this approach will help resolve numerous challenges of space health and combat several health disorders associated with mitochondrial dysfunction.
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Affiliation(s)
- Agata M Rudolf
- Department of Biological Sciences, Auburn University, Auburn, AL, USA; Space Technology Centre, AGH University of Science and Technology, Krakow, Poland.
| | - Wendy R Hood
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
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Haley B, Zander A, Popović J, Paunesku T, Woloschak GE. Findings from international archived data: Fractionation reduces mortality risk of ionizing radiation for total doses below 4 Gray in rodents. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2022; 882:503537. [PMID: 36155139 DOI: 10.1016/j.mrgentox.2022.503537] [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: 04/07/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 06/16/2023]
Abstract
Ionizing radiation is omnipresent and unavoidable on Earth; nevertheless, the range of doses and modes of radiation delivery that represent health risks remain controversial. Radiation protection policy for civilians in US is set at 1 mSv per year. Average persons from contemporary populations are exposed to several hundred milliSieverts (mSv) over their lifetimes from both natural and human made sources such as radon, cosmic rays, CT-scans (20-50 mSv partial body exposure per scan), etc. Health risks associated with these and larger exposures are focus of many epidemiological studies, but uncertainties of these estimates coupled with individual and environmental variation make it is prudent to attempt to use animal models and tightly controlled experimental conditions to supplement our evaluation of radiation risk question. Data on 11,528 of rodents of both genders exposed to x-ray or gamma-ray radiation in facilities in US and Europe were used for this analysis; animal mortality data argue that fractionated radiation exposures have about 2 fold less risk per Gray than acute radiation exposures in the range of doses between 0.25 and 4 Gy.
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Affiliation(s)
- Benjamin Haley
- Feinberg School of Medicine, Department of Radiation Oncology, Northwestern University, Chicago, IL 60611, USA; ClassDojo, 735 Tehama Street, San Francisco CA 94103, USA
| | - Alia Zander
- Feinberg School of Medicine, Department of Radiation Oncology, Northwestern University, Chicago, IL 60611, USA; Chicago-Tempus Headquarters and Lab, 600 West Chicago Avenue, Suite 510, Chicago, IL 60654, USA
| | - Jelena Popović
- Feinberg School of Medicine, Department of Radiation Oncology, Northwestern University, Chicago, IL 60611, USA
| | - Tatjana Paunesku
- Feinberg School of Medicine, Department of Radiation Oncology, Northwestern University, Chicago, IL 60611, USA
| | - Gayle E Woloschak
- Feinberg School of Medicine, Department of Radiation Oncology, Northwestern University, Chicago, IL 60611, USA.
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Zander A, Paunesku T, Woloschak GE. Analyses of cancer incidence and other morbidities in gamma irradiated B6CF1 mice. PLoS One 2020; 15:e0231510. [PMID: 32818954 PMCID: PMC7440931 DOI: 10.1371/journal.pone.0231510] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022] Open
Abstract
With increasing medical radiation exposures, it is important to understand how different modes of delivery of ionizing radiation as well as total doses of exposure impact health outcomes. Our lab studied the risks associated with ionizing radiation by analyzing the Northwestern University Radiation Archive for animals (NURA). NURA contains detailed data from a series of 10 individual neutron and gamma irradiation experiments conducted on over 50,000 mice. Rigorous statistical testing on control mice from all Janus experiments enabled us to select studies that could be compared to one another and uncover unexpected differences among the controls as well as experimental animals. For controls, mice sham irradiated with 300 fractions died significantly earlier than those with fewer sham fractions and were excluded from the pooled dataset. Using the integrated dataset of gamma irradiated and control mice, we found that fractionation significantly decreased the death hazard for animals dying of lymphomas, tumors, non-tumors, and unknown causes. Gender differences in frequencies of causes of death were identified irrespective of irradiation and dose fractionation, with female mice being at a greater risk for all causes of death, except for lung tumors. Irradiated and control male mice were at a significantly greater risk for lung tumors, the opposite from observations noted in humans. Additionally, we discovered that lymphoma deaths can occur quickly after exposures to high doses of gamma rays. This study systematically cross-compared outcomes of different modes of fractionation evaluated across different Janus experiments and across a wide span of total doses. It demonstrates that protraction modulated survival and disease status differently based on the total dose, cause of death, and sex of an animal. This novel method for analyzing the Janus datasets will lead to insightful new mechanistic hypotheses and research in the fields of radiation biology and protection.
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Affiliation(s)
- Alia Zander
- Feinberg School of Medicine, Radiation Oncology, Northwestern University, Chicago, IL, United States of America
| | - Tatjana Paunesku
- Feinberg School of Medicine, Radiation Oncology, Northwestern University, Chicago, IL, United States of America
| | - Gayle E. Woloschak
- Feinberg School of Medicine, Radiation Oncology, Northwestern University, Chicago, IL, United States of America
- * E-mail:
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Schofield PN, Kulka U, Tapio S, Grosche B. Big data in radiation biology and epidemiology; an overview of the historical and contemporary landscape of data and biomaterial archives. Int J Radiat Biol 2019; 95:861-878. [DOI: 10.1080/09553002.2019.1589026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Paul N. Schofield
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, UK
| | - Ulrike Kulka
- Bundesamt fuer Strahlenschutz, Neuherberg, Germany
| | - Soile Tapio
- Helmholtz Zentrum Muenchen, German Research Center for Environmental Health GmbH, Institute of Radiation Biology, Neuherberg, Germany
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Havighorst A, Crossland J, Kiaris H. Peromyscus as a model of human disease. Semin Cell Dev Biol 2016; 61:150-155. [PMID: 27375227 DOI: 10.1016/j.semcdb.2016.06.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/29/2016] [Indexed: 12/20/2022]
Abstract
Animals of the genus Peromyscus have been a particularly informative model for many areas of study, including behavior, evolution, anatomy, physiology and genetics. While their use in modeling human disease and pathology has been relatively restricted, certain qualities of Peromyscine mice may make them a good candidate for such studies. Pathophysiological conditions where Peromyscus may be of particular value involve aging, reactive oxygen species-associated pathologies, metabolism and detoxification, diabetes, and certain cancers. In this review article we will summarize pathological conditions where Peromyscus have been used effectively, we will discuss factors limiting the use of Peromyscus in studying pathology and we will indicate areas at which the use of this model may be of special value.
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Affiliation(s)
- Amanda Havighorst
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, SC, USA; Peromyscus Genetic Stock Center, Office of Research, University of South Carolina, SC, USA
| | - Janet Crossland
- Peromyscus Genetic Stock Center, Office of Research, University of South Carolina, SC, USA
| | - Hippokratis Kiaris
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, SC, USA; Peromyscus Genetic Stock Center, Office of Research, University of South Carolina, SC, USA; Department of Biochemistry, University of Athens Medical School, Athens, Greece.
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