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Vozenin MC, Alaghband Y, Drayson OGG, Piaget F, Leavitt R, Allen BD, Doan NL, Rostomyan T, Stabilini A, Reggiani D, Hajdas W, Yukihara EG, Norbury JW, Bailat C, Desorgher L, Baulch JE, Limoli CL. More May Not be Better: Enhanced Spacecraft Shielding May Exacerbate Cognitive Decrements by Increasing Pion Exposures during Deep Space Exploration. Radiat Res 2024; 201:93-103. [PMID: 38171489 DOI: 10.1667/rade-23-00241.1.s1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024]
Abstract
The pervasiveness of deep space radiation remains a confounding factor for the transit of humans through our solar system. Spacecraft shielding both protects astronauts but also contributes to absorbed dose through galactic cosmic ray interactions that produce secondary particles. The resultant biological effects drop to a minimum for aluminum shielding around 20 g/cm2 but increase with additional shielding. The present work evaluates for the first time, the impact of secondary pions on central nervous system functionality. The fractional pion dose emanating from thicker shielded spacecraft regions could contribute up to 10% of the total absorbed radiation dose. New results from the Paul Scherrer Institute have revealed that low dose exposures to 150 MeV positive and negative pions, akin to a Mars mission, result in significant, long-lasting cognitive impairments. These surprising findings emphasize the need to carefully evaluate shielding configurations to optimize safe exposure limits for astronauts during deep space travel.
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Affiliation(s)
- Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Yasaman Alaghband
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Olivia G G Drayson
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Filippo Piaget
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Ron Leavitt
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | | | | | | | | | | | | | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Laurent Desorgher
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
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Allen BD, Alaghband Y, Kramár EA, Ru N, Petit B, Grilj V, Petronek MS, Pulliam CF, Kim RY, Doan NL, Baulch JE, Wood MA, Bailat C, Spitz DR, Vozenin MC, Limoli CL. Elucidating the neurological mechanism of the FLASH effect in juvenile mice exposed to hypofractionated radiotherapy. Neuro Oncol 2023; 25:927-939. [PMID: 36334265 PMCID: PMC10158064 DOI: 10.1093/neuonc/noac248] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Ultrahigh dose-rate radiotherapy (FLASH-RT) affords improvements in the therapeutic index by minimizing normal tissue toxicities without compromising antitumor efficacy compared to conventional dose-rate radiotherapy (CONV-RT). To investigate the translational potential of FLASH-RT to a human pediatric medulloblastoma brain tumor, we used a radiosensitive juvenile mouse model to assess adverse long-term neurological outcomes. METHODS Cohorts of 3-week-old male and female C57Bl/6 mice exposed to hypofractionated (2 × 10 Gy, FLASH-RT or CONV-RT) whole brain irradiation and unirradiated controls underwent behavioral testing to ascertain cognitive status four months posttreatment. Animals were sacrificed 6 months post-irradiation and tissues were analyzed for neurological and cerebrovascular decrements. RESULTS The neurological impact of FLASH-RT was analyzed over a 6-month follow-up. FLASH-RT ameliorated neurocognitive decrements induced by CONV-RT and preserved synaptic plasticity and integrity at the electrophysiological (long-term potentiation), molecular (synaptophysin), and structural (Bassoon/Homer-1 bouton) levels in multiple brain regions. The benefits of FLASH-RT were also linked to reduced neuroinflammation (activated microglia) and the preservation of the cerebrovascular structure, by maintaining aquaporin-4 levels and minimizing microglia colocalized to vessels. CONCLUSIONS Hypofractionated FLASH-RT affords significant and long-term normal tissue protection in the radiosensitive juvenile mouse brain when compared to CONV-RT. The capability of FLASH-RT to preserve critical cognitive outcomes and electrophysiological properties over 6-months is noteworthy and highlights its potential for resolving long-standing complications faced by pediatric brain tumor survivors. While care must be exercised before clinical translation is realized, present findings document the marked benefits of FLASH-RT that extend from synapse to cognition and the microvasculature.
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Affiliation(s)
- Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Yasaman Alaghband
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Eniko A Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Ning Ru
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Benoit Petit
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Veljko Grilj
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Michael S Petronek
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
| | - Casey F Pulliam
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
| | - Rachel Y Kim
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Claude Bailat
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - Douglas R Spitz
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
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Alaghband Y, Allen BD, Kramár EA, Zhang R, Drayson OG, Ru N, Petit B, Almeida A, Doan NL, Wood MA, Baulch JE, Ballesteros-Zebadua P, Vozenin MC, Limoli CL. Uncovering the Protective Neurologic Mechanisms of Hypofractionated FLASH Radiotherapy. Cancer Res Commun 2023; 3:725-737. [PMID: 37377749 PMCID: PMC10135433 DOI: 10.1158/2767-9764.crc-23-0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 03/26/2023] [Accepted: 03/28/2023] [Indexed: 06/29/2023]
Abstract
Implementation of ultra-high dose-rate FLASH radiotherapy (FLASH-RT) is rapidly gaining traction as a unique cancer treatment modality able to dramatically minimize normal tissue toxicity while maintaining antitumor efficacy compared with standard-of-care radiotherapy at conventional dose rate (CONV-RT). The resultant improvements in the therapeutic index have sparked intense investigations in pursuit of the underlying mechanisms. As a preamble to clinical translation, we exposed non-tumor-bearing male and female mice to hypofractionated (3 × 10 Gy) whole brain FLASH- and CONV-RT to evaluate differential neurologic responses using a comprehensive panel of functional and molecular outcomes over a 6-month follow-up. In each instance, extensive and rigorous behavioral testing showed FLASH-RT to preserve cognitive indices of learning and memory that corresponded to a similar protection of synaptic plasticity as measured by long-term potentiation (LTP). These beneficial functional outcomes were not found after CONV-RT and were linked to a preservation of synaptic integrity at the molecular (synaptophysin) level and to reductions in neuroinflammation (CD68+ microglia) throughout specific brain regions known to be engaged by our selected cognitive tasks (hippocampus, medial prefrontal cortex). Ultrastructural changes in presynaptic/postsynaptic bouton (Bassoon/Homer-1 puncta) within these same regions of the brain were not found to differ in response to dose rate. With this clinically relevant dosing regimen, we provide a mechanistic blueprint from synapse to cognition detailing how FLASH-RT reduces normal tissue complications in the irradiated brain. Significance Functional preservation of cognition and LTP after hypofractionated FLASH-RT are linked to a protection of synaptic integrity and a reduction in neuroinflammation over protracted after irradiation times.
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Affiliation(s)
- Yasaman Alaghband
- Department of Radiation Oncology, University of California, Irvine, California
| | - Barrett D. Allen
- Department of Radiation Oncology, University of California, Irvine, California
| | - Eniko A. Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Richard Zhang
- Department of Radiation Oncology, University of California, Irvine, California
| | - Olivia G.G. Drayson
- Department of Radiation Oncology, University of California, Irvine, California
| | - Ning Ru
- Department of Radiation Oncology, University of California, Irvine, California
| | - Benoit Petit
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Aymeric Almeida
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, University of California, Irvine, California
| | - Marcelo A. Wood
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Janet E. Baulch
- Department of Radiation Oncology, University of California, Irvine, California
| | - Paola Ballesteros-Zebadua
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Instituto Nacional de Neurología y Neurocirugía MVS, México City, México
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Charles L. Limoli
- Department of Radiation Oncology, University of California, Irvine, California
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4
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Alaghband Y, Klein PM, Kramár EA, Cranston MN, Perry BC, Shelerud LM, Kane AE, Doan NL, Ru N, Acharya MM, Wood MA, Sinclair DA, Dickstein DL, Soltesz I, Limoli CL, Baulch JE. Galactic cosmic radiation exposure causes multifaceted neurocognitive impairments. Cell Mol Life Sci 2023; 80:29. [PMID: 36607431 PMCID: PMC9823026 DOI: 10.1007/s00018-022-04666-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 11/01/2022] [Accepted: 12/11/2022] [Indexed: 01/07/2023]
Abstract
Technological advancements have facilitated the implementation of realistic, terrestrial-based complex 33-beam galactic cosmic radiation simulations (GCR Sim) to now probe central nervous system functionality. This work expands considerably on prior, simplified GCR simulations, yielding new insights into responses of male and female mice exposed to 40-50 cGy acute or chronic radiations relevant to deep space travel. Results of the object in updated location task suggested that exposure to acute or chronic GCR Sim induced persistent impairments in hippocampus-dependent memory formation and reconsolidation in female mice that did not manifest robustly in irradiated male mice. Interestingly, irradiated male mice, but not females, were impaired in novel object recognition and chronically irradiated males exhibited increased aggressive behavior on the tube dominance test. Electrophysiology studies used to evaluate synaptic plasticity in the hippocampal CA1 region revealed significant reductions in long-term potentiation after each irradiation paradigm in both sexes. Interestingly, network-level disruptions did not translate to altered intrinsic electrophysiological properties of CA1 pyramidal cells, whereas acute exposures caused modest drops in excitatory synaptic signaling in males. Ultrastructural analyses of CA1 synapses found smaller postsynaptic densities in larger spines of chronically exposed mice compared to controls and acutely exposed mice. Myelination was also affected by GCR Sim with acutely exposed mice exhibiting an increase in the percent of myelinated axons; however, the myelin sheathes on small calibur (< 0.3 mm) and larger (> 0.5 mm) axons were thinner when compared to controls. Present findings might have been predicted based on previous studies using single and mixed beam exposures and provide further evidence that space-relevant radiation exposures disrupt critical cognitive processes and underlying neuronal network-level plasticity, albeit not to the extent that might have been previously predicted.
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Affiliation(s)
- Yasaman Alaghband
- Department of Radiation Oncology, Medical Sciences I, University of California Irvine, Room B-146D, Irvine, CA, 92697-2695, USA
| | - Peter M Klein
- Department of Neurosurgery, Stanford University, Palo Alto, CA, 94305, USA
| | - Eniko A Kramár
- Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, 92697-2695, USA
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, 92697-2695, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, 92697-2695, USA
| | - Michael N Cranston
- Department of Pathology, Uniformed Services University of Health Sciences, Bethesda, MD, 20814, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), Bethesda, MD, 20817, USA
| | - Bayley C Perry
- Department of Pathology, Uniformed Services University of Health Sciences, Bethesda, MD, 20814, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), Bethesda, MD, 20817, USA
| | - Lukas M Shelerud
- Department of Genetics, Blavatnik Institute, Paul F. Glenn Center for Biology of Aging Research, Harvard Medical School, Boston, MA, 0211, USA
| | - Alice E Kane
- Department of Genetics, Blavatnik Institute, Paul F. Glenn Center for Biology of Aging Research, Harvard Medical School, Boston, MA, 0211, USA
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, Medical Sciences I, University of California Irvine, Room B-146D, Irvine, CA, 92697-2695, USA
| | - Ning Ru
- Department of Radiation Oncology, Medical Sciences I, University of California Irvine, Room B-146D, Irvine, CA, 92697-2695, USA
| | - Munjal M Acharya
- Department of Radiation Oncology, Medical Sciences I, University of California Irvine, Room B-146D, Irvine, CA, 92697-2695, USA
- Department of Anatomy and Neurobiology, University of California, Irvine, 92697-2695, USA
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, 92697-2695, USA
| | - David A Sinclair
- Department of Genetics, Blavatnik Institute, Paul F. Glenn Center for Biology of Aging Research, Harvard Medical School, Boston, MA, 0211, USA
| | - Dara L Dickstein
- Department of Pathology, Uniformed Services University of Health Sciences, Bethesda, MD, 20814, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), Bethesda, MD, 20817, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Palo Alto, CA, 94305, USA
- Department of Neurology and Neurological Sciences, Stanford University, Palo Alto, CA, 94305, USA
| | - Charles L Limoli
- Department of Radiation Oncology, Medical Sciences I, University of California Irvine, Room B-146D, Irvine, CA, 92697-2695, USA
| | - Janet E Baulch
- Department of Radiation Oncology, Medical Sciences I, University of California Irvine, Room B-146D, Irvine, CA, 92697-2695, USA.
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Klein PM, Alaghband Y, Doan NL, Ru N, Drayson OGG, Baulch JE, Kramár EA, Wood MA, Soltesz I, Limoli CL. Acute, Low-Dose Neutron Exposures Adversely Impact Central Nervous System Function. Int J Mol Sci 2021; 22:9020. [PMID: 34445726 PMCID: PMC8396607 DOI: 10.3390/ijms22169020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 02/06/2023] Open
Abstract
A recognized risk of long-duration space travel arises from the elevated exposure astronauts face from galactic cosmic radiation (GCR), which is composed of a diverse array of energetic particles. There is now abundant evidence that exposures to many different charged particle GCR components within acute time frames are sufficient to induce central nervous system deficits that span from the molecular to the whole animal behavioral scale. Enhanced spacecraft shielding can lessen exposures to charged particle GCR components, but may conversely elevate neutron radiation levels. We previously observed that space-relevant neutron radiation doses, chronically delivered at dose-rates expected during planned human exploratory missions, can disrupt hippocampal neuronal excitability, perturb network long-term potentiation and negatively impact cognitive behavior. We have now determined that acute exposures to similar low doses (18 cGy) of neutron radiation can also lead to suppressed hippocampal synaptic signaling, as well as decreased learning and memory performance in male mice. Our results demonstrate that similar nervous system hazards arise from neutron irradiation regardless of the exposure time course. While not always in an identical manner, neutron irradiation disrupts many of the same central nervous system elements as acute charged particle GCR exposures. The risks arising from neutron irradiation are therefore important to consider when determining the overall hazards astronauts will face from the space radiation environment.
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Affiliation(s)
- Peter M. Klein
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; (P.M.K.); (I.S.)
| | - Yasaman Alaghband
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Ning Ru
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Olivia G. G. Drayson
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Janet E. Baulch
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Enikö A. Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA; (E.A.K.); (M.A.W.)
| | - Marcelo A. Wood
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA; (E.A.K.); (M.A.W.)
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; (P.M.K.); (I.S.)
| | - Charles L. Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
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