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Zhang Y, Zhang Y, Shen C, Hao S, Duan W, Liu L, Wei H. Ionizing radiation alters functional neurotransmission in Drosophila larvae. Front Cell Neurosci 2023; 17:1151489. [PMID: 37484822 PMCID: PMC10357008 DOI: 10.3389/fncel.2023.1151489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
Introduction Patients undergoing cranial ionizing radiation therapy for brain malignancies are at increased risk of long-term neurocognitive decline, which is poorly understood and currently untreatable. Although the molecular pathogenesis has been intensively researched in many organisms, whether and how ionizing radiation alters functional neurotransmission remains unknown. This is the first study addressing physiological changes in neurotransmission after ionizing radiation exposure. Methods To elucidate the cellular mechanisms of radiation damage, using calcium imaging, we analyzed the effects of ionizing radiation on the neurotransmitter-evoked responses of prothoracicotropic hormone (PTTH)-releasing neurons in Drosophila larvae, which play essential roles in normal larval development. Results The neurotransmitters dopamine and tyramine decreased intracellular calcium levels of PTTH neurons in a dose-dependent manner. In gamma irradiated third-instar larvae, a dose of 25 Gy increased the sensitivity of PTTH neurons to dopamine and tyramine, and delayed development, possibly in response to abnormal functional neurotransmission. This irradiation level did not affect the viability and arborization of PTTH neurons and successful survival to adulthood. Exposure to a 40-Gy dose of gamma irradiation decreased the neurotransmitter sensitivity, physiological viability and axo-dendritic length of PTTH neurons. These serious damages led to substantial developmental delays and a precipitous reduction in the percentage of larvae that survived to adulthood. Our results demonstrate that gamma irradiation alters neurotransmitter-evoked responses, indicating synapses are vulnerable targets of ionizing radiation. Discussion The current study provides new insights into ionizing radiation-induced disruption of physiological neurotransmitter signaling, which should be considered in preventive therapeutic interventions to reduce risks of neurological deficits after photon therapy.
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Affiliation(s)
- Yi Zhang
- North China Research Institute of Electro-Optics, Beijing, China
| | - Yihao Zhang
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Cong Shen
- China Electronics Technology Group Corporation No. 45 Research Institute, Beijing, China
| | - Shun Hao
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Wenlan Duan
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Li Liu
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Hongying Wei
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
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Peter JS, Schuemann J, Held KD, McNamara AL. Nano-scale simulation of neuronal damage by galactic cosmic rays. Phys Med Biol 2022; 67:10.1088/1361-6560/ac95f4. [PMID: 36172820 PMCID: PMC9951267 DOI: 10.1088/1361-6560/ac95f4] [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: 02/14/2022] [Accepted: 09/28/2022] [Indexed: 11/11/2022]
Abstract
The effects of realistic, deep space radiation environments on neuronal function remain largely unexplored.In silicomodeling studies of radiation-induced neuronal damage provide important quantitative information about physico-chemical processes that are not directly accessible through radiobiological experiments. Here, we present the first nano-scale computational analysis of broad-spectrum galactic cosmic ray irradiation in a realistic neuron geometry. We constructed thousands ofin silicorealizations of a CA1 pyramidal neuron, each with over 3500 stochastically generated dendritic spines. We simulated the entire 33 ion-energy beam spectrum currently in use at the NASA Space Radiation Laboratory galactic cosmic ray simulator (GCRSim) using the TOol for PArticle Simulation (TOPAS) and TOPAS-nBio Monte Carlo-based track structure simulation toolkits. We then assessed the resulting nano-scale dosimetry, physics processes, and fluence patterns. Additional comparisons were made to a simplified 6 ion-energy spectrum (SimGCRSim) also used in NASA experiments. For a neuronal absorbed dose of 0.5 Gy GCRSim, we report an average of 250 ± 10 ionizations per micrometer of dendritic length, and an additional 50 ± 10, 7 ± 2, and 4 ± 2 ionizations per mushroom, thin, and stubby spine, respectively. We show that neuronal energy deposition by proton andα-particle tracks declines approximately hyperbolically with increasing primary particle energy at mission-relevant energies. We demonstrate an inverted exponential relationship between dendritic segment irradiation probability and neuronal absorbed dose for each ion-energy beam. We also find that there are no significant differences in the average physical responses between the GCRSim and SimGCRSim spectra. To our knowledge, this is the first nano-scale simulation study of a realistic neuron geometry using the GCRSim and SimGCRSim spectra. These results may be used as inputs to theoretical models, aid in the interpretation of experimental results, and help guide future study designs.
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Affiliation(s)
- Jonah S Peter
- Biophysics Program, Harvard University, Boston, MA 02115, United States of America
- Department of Radiation Oncology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, United States of America
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, United States of America
| | - Kathryn D Held
- Department of Radiation Oncology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, United States of America
| | - Aimee L McNamara
- Department of Radiation Oncology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, United States of America
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3
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Prelich MT, Matar M, Gokoglu SA, Gallo CA, Schepelmann A, Iqbal AK, Lewandowski BE, Britten RA, Prabhu RK, Myers JG. Predicting Space Radiation Single Ion Exposure in Rodents: A Machine Learning Approach. Front Syst Neurosci 2021; 15:715433. [PMID: 34720896 PMCID: PMC8555470 DOI: 10.3389/fnsys.2021.715433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
This study presents a data-driven machine learning approach to predict individual Galactic Cosmic Radiation (GCR) ion exposure for 4He, 16O, 28Si, 48Ti, or 56Fe up to 150 mGy, based on Attentional Set-shifting (ATSET) experimental tests. The ATSET assay consists of a series of cognitive performance tasks on irradiated male Wistar rats. The GCR ion doses represent the expected cumulative radiation astronauts may receive during a Mars mission on an individual ion basis. The primary objective is to synthesize and assess predictive models on a per-subject level through Machine Learning (ML) classifiers. The raw cognitive performance data from individual rodent subjects are used as features to train the models and to explore the capabilities of three different ML techniques for elucidating a range of correlations between received radiation on rodents and their performance outcomes. The analysis employs scores of selected input features and different normalization approaches which yield varying degrees of model performance. The current study shows that support vector machine, Gaussian naive Bayes, and random forest models are capable of predicting individual ion exposure using ATSET scores where corresponding Matthews correlation coefficients and F1 scores reflect model performance exceeding random chance. The study suggests a decremental effect on cognitive performance in rodents due to ≤150 mGy of single ion exposure, inasmuch as the models can discriminate between 0 mGy and any exposure level in the performance score feature space. A number of observations about the utility and limitations in specific normalization routines and evaluation scores are examined as well as best practices for ML with imbalanced datasets observed.
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Affiliation(s)
| | - Mona Matar
- NASA Glenn Research Center, Cleveland, OH, United States
| | | | | | | | - Asad K Iqbal
- ZIN Technologies, Inc., Cleveland, OH, United States
| | | | - Richard A Britten
- Department of Radiation Oncology, Eastern Virginia Medical School, Norfolk, VA, United States
| | - R K Prabhu
- Universities Space Research Association, Cleveland, OH, United States
| | - Jerry G Myers
- NASA Glenn Research Center, Cleveland, OH, United States
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4
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Matar M, Gokoglu SA, Prelich MT, Gallo CA, Iqbal AK, Britten RA, Prabhu RK, Myers JG. Machine Learning Models to Predict Cognitive Impairment of Rodents Subjected to Space Radiation. Front Syst Neurosci 2021; 15:713131. [PMID: 34588962 PMCID: PMC8473791 DOI: 10.3389/fnsys.2021.713131] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022] Open
Abstract
This research uses machine-learned computational analyses to predict the cognitive performance impairment of rats induced by irradiation. The experimental data in the analyses is from a rodent model exposed to ≤15 cGy of individual galactic cosmic radiation (GCR) ions: 4He, 16O, 28Si, 48Ti, or 56Fe, expected for a Lunar or Mars mission. This work investigates rats at a subject-based level and uses performance scores taken before irradiation to predict impairment in attentional set-shifting (ATSET) data post-irradiation. Here, the worst performing rats of the control group define the impairment thresholds based on population analyses via cumulative distribution functions, leading to the labeling of impairment for each subject. A significant finding is the exhibition of a dose-dependent increasing probability of impairment for 1 to 10 cGy of 28Si or 56Fe in the simple discrimination (SD) stage of the ATSET, and for 1 to 10 cGy of 56Fe in the compound discrimination (CD) stage. On a subject-based level, implementing machine learning (ML) classifiers such as the Gaussian naïve Bayes, support vector machine, and artificial neural networks identifies rats that have a higher tendency for impairment after GCR exposure. The algorithms employ the experimental prescreen performance scores as multidimensional input features to predict each rodent's susceptibility to cognitive impairment due to space radiation exposure. The receiver operating characteristic and the precision-recall curves of the ML models show a better prediction of impairment when 56Fe is the ion in question in both SD and CD stages. They, however, do not depict impairment due to 4He in SD and 28Si in CD, suggesting no dose-dependent impairment response in these cases. One key finding of our study is that prescreen performance scores can be used to predict the ATSET performance impairments. This result is significant to crewed space missions as it supports the potential of predicting an astronaut's impairment in a specific task before spaceflight through the implementation of appropriately trained ML tools. Future research can focus on constructing ML ensemble methods to integrate the findings from the methodologies implemented in this study for more robust predictions of cognitive decrements due to space radiation exposure.
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Affiliation(s)
- Mona Matar
- NASA Glenn Research Center, Cleveland, OH, United States
| | | | | | | | - Asad K. Iqbal
- ZIN Technologies, Inc., Cleveland, OH, United States
| | - Richard A. Britten
- Department of Radiation Oncology, Eastern Virginia Medical School, Norfolk, VA, United States
| | - R. K. Prabhu
- Universities Space Research Association, Cleveland, OH, United States
| | - Jerry G. Myers
- NASA Glenn Research Center, Cleveland, OH, United States
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Suckert T, Nexhipi S, Dietrich A, Koch R, Kunz-Schughart LA, Bahn E, Beyreuther E. Models for Translational Proton Radiobiology-From Bench to Bedside and Back. Cancers (Basel) 2021; 13:4216. [PMID: 34439370 PMCID: PMC8395028 DOI: 10.3390/cancers13164216] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/09/2021] [Accepted: 08/17/2021] [Indexed: 12/25/2022] Open
Abstract
The number of proton therapy centers worldwide are increasing steadily, with more than two million cancer patients treated so far. Despite this development, pending questions on proton radiobiology still call for basic and translational preclinical research. Open issues are the on-going discussion on an energy-dependent varying proton RBE (relative biological effectiveness), a better characterization of normal tissue side effects and combination treatments with drugs originally developed for photon therapy. At the same time, novel possibilities arise, such as radioimmunotherapy, and new proton therapy schemata, such as FLASH irradiation and proton mini-beams. The study of those aspects demands for radiobiological models at different stages along the translational chain, allowing the investigation of mechanisms from the molecular level to whole organisms. Focusing on the challenges and specifics of proton research, this review summarizes the different available models, ranging from in vitro systems to animal studies of increasing complexity as well as complementing in silico approaches.
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Affiliation(s)
- Theresa Suckert
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (T.S.); (S.N.); (A.D.); (L.A.K.-S.)
- German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Sindi Nexhipi
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (T.S.); (S.N.); (A.D.); (L.A.K.-S.)
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, 01309 Dresden, Germany
| | - Antje Dietrich
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (T.S.); (S.N.); (A.D.); (L.A.K.-S.)
- German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Robin Koch
- Heidelberg Institute of Radiation Oncology (HIRO), 69120 Heidelberg, Germany; (R.K.); (E.B.)
- Department of Radiation Oncology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany
| | - Leoni A. Kunz-Schughart
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (T.S.); (S.N.); (A.D.); (L.A.K.-S.)
- National Center for Tumor Diseases (NCT), Partner Site Dresden, 01307 Dresden, Germany
| | - Emanuel Bahn
- Heidelberg Institute of Radiation Oncology (HIRO), 69120 Heidelberg, Germany; (R.K.); (E.B.)
- Department of Radiation Oncology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany
- German Cancer Research Center (DKFZ), Clinical Cooperation Unit Radiation Oncology, 69120 Heidelberg, Germany
| | - Elke Beyreuther
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (T.S.); (S.N.); (A.D.); (L.A.K.-S.)
- Helmholtz-Zentrum Dresden—Rossendorf, Institute of Radiation Physics, 01328 Dresden, Germany
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6
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Limoli C. Can a comparison of clinical and deep space irradiation scenarios shed light on the radiation response of the brain? Br J Radiol 2020; 93:20200245. [PMID: 32970457 DOI: 10.1259/bjr.20200245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Not surprisingly, our knowledge of the impact of radiation on the brain has evolved considerably. Decades of work have struggled with identifying the critical cellular targets in the brain, the latency of functional change and understanding how irradiation alters the balance between excitatory and inhibitory circuits. Radiation-induced cell kill following clinical fractionation paradigms pointed to both stromal and parenchymal targets but also defined an exquisite sensitivity of neurogenic populations of newly born cells in the brain. It became more and more apparent too, that acute (days) events transpiring after exposure were poorly prognostic of the late (months-years) waves of radiation injury believed to underlie neurocognitive deficits. Much of these gaps in knowledge persisted as NASA became interested in how exposure to much different radiation types, doses and dose rates that characterize the space radiation environment might impair central nervous system functionality, with possibly negative implications for deep space travel. Now emerging evidence from researchers engaged in clinical, translational and environmental radiation sciences have begun to fill these gaps and have uncovered some surprising similarities in the response of the brain to seemingly disparate exposure scenarios. This article highlights many of the commonalities between the vastly different irradiation paradigms that distinguish clinical treatments from occupational exposures in deep space.
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Affiliation(s)
- Charles Limoli
- Department of Radiation Oncology, University of California, Irvine, CA, United States
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Parihar VK, Angulo MC, Allen BD, Syage A, Usmani MT, Passerat de la Chapelle E, Amin AN, Flores L, Lin X, Giedzinski E, Limoli CL. Sex-Specific Cognitive Deficits Following Space Radiation Exposure. Front Behav Neurosci 2020; 14:535885. [PMID: 33192361 PMCID: PMC7525092 DOI: 10.3389/fnbeh.2020.535885] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022] Open
Abstract
The radiation fields in space define tangible risks to the health of astronauts, and significant work in rodent models has clearly shown a variety of exposure paradigms to compromise central nervous system (CNS) functionality. Despite our current knowledge, sex differences regarding the risks of space radiation exposure on cognitive function remain poorly understood, which is potentially problematic given that 30% of astronauts are women. While work from us and others have demonstrated pronounced cognitive decrements in male mice exposed to charged particle irradiation, here we show that female mice exhibit significant resistance to adverse neurocognitive effects of space radiation. The present findings indicate that male mice exposed to low doses (≤30 cGy) of energetic (400 MeV/n) helium ions (4He) show significantly higher levels of neuroinflammation and more extensive cognitive deficits than females. Twelve weeks following 4He ion exposure, irradiated male mice demonstrated significant deficits in object and place recognition memory accompanied by activation of microglia, marked upregulation of hippocampal Toll-like receptor 4 (TLR4), and increased expression of the pro-inflammatory marker high mobility group box 1 protein (HMGB1). Additionally, we determined that exposure to 4He ions caused a significant decline in the number of dendritic branch points and total dendritic length along with the hippocampus neurons in female mice. Interestingly, only male mice showed a significant decline of dendritic spine density following irradiation. These data indicate that fundamental differences in inflammatory cascades between male and female mice may drive divergent CNS radiation responses that differentially impact the structural plasticity of neurons and neurocognitive outcomes following cosmic radiation exposure.
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Affiliation(s)
- Vipan K Parihar
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Maria C Angulo
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Amber Syage
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Manal T Usmani
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | | | - Amal Nayan Amin
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Lidia Flores
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Xiaomeng Lin
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Erich Giedzinski
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA, United States
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Allen BD, Syage AR, Maroso M, Baddour AAD, Luong V, Minasyan H, Giedzinski E, West BL, Soltesz I, Limoli CL, Baulch JE, Acharya MM. Mitigation of helium irradiation-induced brain injury by microglia depletion. J Neuroinflammation 2020; 17:159. [PMID: 32429943 PMCID: PMC7236926 DOI: 10.1186/s12974-020-01790-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 03/26/2020] [Indexed: 12/11/2022] Open
Abstract
Background Cosmic radiation exposures have been found to elicit cognitive impairments involving a wide-range of underlying neuropathology including elevated oxidative stress, neural stem cell loss, and compromised neuronal architecture. Cognitive impairments have also been associated with sustained microglia activation following low dose exposure to helium ions. Space-relevant charged particles elicit neuroinflammation that persists long-term post-irradiation. Here, we investigated the potential neurocognitive benefits of microglia depletion following low dose whole body exposure to helium ions. Methods Adult mice were administered a dietary inhibitor (PLX5622) of colony stimulating factor-1 receptor (CSF1R) to deplete microglia 2 weeks after whole body helium irradiation (4He, 30 cGy, 400 MeV/n). Cohorts of mice maintained on a normal and PLX5622 diet were tested for cognitive function using seven independent behavioral tasks, microglial activation, hippocampal neuronal morphology, spine density, and electrophysiology properties 4–6 weeks later. Results PLX5622 treatment caused a rapid and near complete elimination of microglia in the brain within 3 days of treatment. Irradiated animals on normal diet exhibited a range of behavioral deficits involving the medial pre-frontal cortex and hippocampus and increased microglial activation. Animals on PLX5622 diet exhibited no radiation-induced cognitive deficits, and expression of resting and activated microglia were almost completely abolished, without any effects on the oligodendrocyte progenitors, throughout the brain. While PLX5622 treatment was found to attenuate radiation-induced increases in post-synaptic density protein 95 (PSD-95) puncta and to preserve mushroom type spine densities, other morphologic features of neurons and electrophysiologic measures of intrinsic excitability were relatively unaffected. Conclusions Our data suggest that microglia play a critical role in cosmic radiation-induced cognitive deficits in mice and, that approaches targeting microglial function are poised to provide considerable benefit to the brain exposed to charged particles.
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Affiliation(s)
- Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | - Amber R Syage
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | - Mattia Maroso
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Al Anoud D Baddour
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | - Valerie Luong
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | - Harutyun Minasyan
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | - Erich Giedzinski
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | | | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, CA, USA
| | - Munjal M Acharya
- Department of Radiation Oncology, University of California, Irvine, CA, USA.
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Acharya MM, Baulch JE, Klein PM, Baddour AAD, Apodaca LA, Kramár EA, Alikhani L, Garcia C, Angulo MC, Batra RS, Fallgren CM, Borak TB, Stark CEL, Wood MA, Britten RA, Soltesz I, Limoli CL. New Concerns for Neurocognitive Function during Deep Space Exposures to Chronic, Low Dose-Rate, Neutron Radiation. eNeuro 2019; 6:ENEURO.0094-19.2019. [PMID: 31383727 PMCID: PMC6709229 DOI: 10.1523/eneuro.0094-19.2019] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/08/2019] [Accepted: 07/16/2019] [Indexed: 12/12/2022] Open
Abstract
As NASA prepares for a mission to Mars, concerns regarding the health risks associated with deep space radiation exposure have emerged. Until now, the impacts of such exposures have only been studied in animals after acute exposures, using dose rates ∼1.5×105 higher than those actually encountered in space. Using a new, low dose-rate neutron irradiation facility, we have uncovered that realistic, low dose-rate exposures produce serious neurocognitive complications associated with impaired neurotransmission. Chronic (6 month) low-dose (18 cGy) and dose rate (1 mGy/d) exposures of mice to a mixed field of neutrons and photons result in diminished hippocampal neuronal excitability and disrupted hippocampal and cortical long-term potentiation. Furthermore, mice displayed severe impairments in learning and memory, and the emergence of distress behaviors. Behavioral analyses showed an alarming increase in risk associated with these realistic simulations, revealing for the first time, some unexpected potential problems associated with deep space travel on all levels of neurological function.
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Affiliation(s)
- Munjal M Acharya
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Peter M Klein
- Department of Neurosurgery, Stanford University, California 94305
| | - Al Anoud D Baddour
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Lauren A Apodaca
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Eniko A Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, California 92697
| | - Leila Alikhani
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Camillo Garcia
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Maria C Angulo
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Raja S Batra
- Department of Radiation Oncology, University of California, Irvine, California 92697
| | - Christine M Fallgren
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Thomas B Borak
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Craig E L Stark
- Department of Neurobiology and Behavior, University of California, Irvine, California 92697
| | - Marcello A Wood
- Department of Neurobiology and Behavior, University of California, Irvine, California 92697
| | - Richard A Britten
- Department of Radiation Oncology, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, California 94305
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, California 92697
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Cucinotta FA, Cacao E. Risks of cognitive detriments after low dose heavy ion and proton exposures. Int J Radiat Biol 2019; 95:985-998. [PMID: 31120359 PMCID: PMC6606350 DOI: 10.1080/09553002.2019.1623427] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/16/2019] [Accepted: 04/25/2019] [Indexed: 12/15/2022]
Abstract
Purpose: Heavy ion and proton brain irradiations occur during space travel and in Hadron therapy for cancer. Heavy ions produce distinct patterns of energy deposition in neuron cells and brain tissues compared to X-rays leading to large uncertainties in risk estimates. We make a critical review of findings from research studies over the last 25 years for understanding risks at low dose. Conclusions: A large number of mouse and rat cognitive testing measures have been reported for a variety of particle species and energies for acute doses. However, tissue reactions occur above dose thresholds and very few studies were performed at the heavy ion doses to be encountered on space missions (<0.04 Gy/y) or considered dose-rate effects, such that threshold doses are not known in rodent models. Investigations of possible mechanisms for cognitive changes have been limited by experimental design with largely group specific and not subject specific findings reported. Persistent oxidative stress and activated microglia cells are common mechanisms studied, while impairment of neurogenesis, detriments in neuron morphology, and changes to gene and protein expression were each found to be important in specific studies. Future research should focus on estimating threshold doses carried out with experimental designs aimed at understating causative mechanisms, which will be essential for extrapolating rodent findings to humans and chronic radiation scenarios, while establishing if mitigation are needed.
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Cucinotta FA, Eliedonna Cacao MA. DETRIMENTS IN NEURON MORPHOLOGY FOLLOWING HEAVY ION IRRADIATION: WHAT'S THE TARGET? RADIATION PROTECTION DOSIMETRY 2019; 183:69-74. [PMID: 30561664 PMCID: PMC6642454 DOI: 10.1093/rpd/ncy265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 11/21/2018] [Indexed: 06/09/2023]
Abstract
Neuron cells consist of the soma or cell body, axons, dendritic arbor with multiple branches, and dendritic spines which are the substrates for memory storage and synaptic transmission. Detriments in neuron morphology are suggested to play a key role in cognitive impairments following brain irradiation. Multiple molecular mechanisms are involved in the regulation and stability of neuron morphology, while the effects of radiation on these processes have not been studied extensively. In this report, we consider possible biological targets in neurons for energy deposition (ED) by charged particles that could lead to neuron morphology detriments, and the resulting dose and radiation quality dependence of such detriments. The track structures of heavy ions including high charge and energy (HZE) particles consists of core of high-ED events and a penumbra of sparse ED from δ-ray electrons produced in ionization of target molecules. We consider the role of track structure relative to possible targets causative in the degradation of morphology.
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Affiliation(s)
- Francis A Cucinotta
- Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas NV, USA
| | - Murat Alp Eliedonna Cacao
- Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas NV, USA
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