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Guan B, Li D, Meng A. Development of radiation countermeasure agents for acute radiation syndromes. Animal Model Exp Med 2023; 6:329-336. [PMID: 37642199 PMCID: PMC10486342 DOI: 10.1002/ame2.12339] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 07/18/2023] [Indexed: 08/31/2023] Open
Abstract
The risk of internal and external exposure to ionizing radiation (IR) has increased alongside the development and implementation of nuclear technology. Therefore, serious security issues have emerged globally, and there has been an increase in the number of studies focusing on radiological prevention and medical countermeasures. Radioprotective drugs are particularly important components of emergency medical preparedness strategies for the clinical management of IR-induced injuries. However, a few drugs have been approved to date to treat such injuries, and the related mechanisms are not entirely understood. Thus, the aim of the present review was to provide a brief overview of the World Health Organization's updated list of essential medicines for 2023 for the proper management of national stockpiles and the treatment of radiological emergencies. This review also discusses the types of radiation-induced health injuries and the related mechanisms, as well as the development of various radioprotective agents, including Chinese herbal medicines, for which significant survival benefits have been demonstrated in animal models of acute radiation syndrome.
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Affiliation(s)
- Bowen Guan
- National Human Diseases Animal Model Resource Center, NHC Key Laboratory of Human Disease Comparative Medicine, Beijing Engineering Research Center for Experimental Animal Models of Human Critical DiseasesInstitute of Laboratory Animal Sciences Chinese Academy of Medical Sciences (CAMS), Peking Union Medical College (PUMC), National Center of Technology Innovation for Animal ModelBeijingChina
| | - Deguan Li
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear MedicineInstitute of Radiation Medicine, Chinese Academy of Medical Science, Peking Union Medical CollegeTianjinChina
| | - Aimin Meng
- National Human Diseases Animal Model Resource Center, NHC Key Laboratory of Human Disease Comparative Medicine, Beijing Engineering Research Center for Experimental Animal Models of Human Critical DiseasesInstitute of Laboratory Animal Sciences Chinese Academy of Medical Sciences (CAMS), Peking Union Medical College (PUMC), National Center of Technology Innovation for Animal ModelBeijingChina
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Chmil V, Filipová A, Tichý A. Looking for the phoenix: the current research on radiation countermeasures. Int J Radiat Biol 2023; 99:1148-1166. [PMID: 36745819 DOI: 10.1080/09553002.2023.2173822] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/06/2022] [Accepted: 12/26/2022] [Indexed: 02/08/2023]
Abstract
PURPOSE Ionizing radiation (IR) is widely applied in radiotherapy for the treatment of over 50% of cancer patients. IR is also intensively used in medical diagnostics on a daily basis in imaging. Moreover, recent geopolitical events have re-ignited the real threat of the use of nuclear weapons. Medical radiation countermeasures represent one of the effective protection strategies against the effects of IR. The aim of this review was to summarize the most commonly used strategies and procedures in the development of radiation countermeasures and to evaluate the current state of their research, with a focus on those in the clinical trial phase. METHODS Clinical trials for this review were selected in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. The search was performed in the clinicaltrials.gov database as of May 2022. RESULTS Our search returned 263 studies, which were screened and of which 25 were included in the review. 10 of these studies had been completed, 3 with promising results: KMRC011 increased G-CSF, IL-6, and neutrophil counts suggesting potential for the treatment of hematopoietic acute radiation syndrome (H-ARS); GC4419 reduced the number of patients with severe oral mucositis and its duration; the combination of enoxaparin, pentoxifylline, and ursodeoxycholic acid reduced the incidence of focal radiation-induced liver injury. CONCLUSION The agents discovered so far show significant side effects or low efficacy, and hence most of the tested agents terminate in the early stages of development. In addition, the low profitability of this type of drug demotivates the private sector to invest in such research. To overcome this problem, there is a need to involve more public resources in funding. Among the technological opportunities, a deeper use of in silico approaches seems to be prospective.
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Affiliation(s)
- Vojtěch Chmil
- Department of Radiobiology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Alžběta Filipová
- Department of Radiobiology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Aleš Tichý
- Department of Radiobiology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
- Biomedical Research Centre, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
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Li P, Chen C, Huang B, Jiang Z, Wei J, Zeng J. Altered excitability of motor neuron pathways after stroke: more than upper motor neuron impairments. Stroke Vasc Neurol 2022; 7:518-526. [PMID: 35772811 PMCID: PMC9811581 DOI: 10.1136/svn-2022-001568] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 06/01/2022] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Previous studies have suggested that impairment occurs in the lower motor neuron (LMN) pathway after stroke, but more research remains to be supported. OBJECTIVE In this study, we tested the hypotheses: (1) both motor cortex and peripheral nerve pathways have decreased excitability and structural damage after stroke; (2) parameters of transcranial magnetic stimulation motor evoked potentials (TMS-MEP) can be used as predictors of motor function and stroke prognosis. METHODS We studied five male cynomolgus monkeys with ischaemic stroke. TMS-MEP, cranial MRI, behavioural assessment, neurological scales and pathology were applied. RESULTS Elevated resting motor threshold (RMT) (p<0.05), decreased TMS-MEP amplitudes (p<0.05) and negative RMT lateralisation were detected in both the affected motor cortex (AMC) and the paretic side median nerve (PMN) at 2 weeks poststroke. Disturbed structure and loose arrangement of myelin sheaths were observed in the PMN through H&E staining and LFB staining at 12 weeks poststroke. The primate Rankin Scale (used for assess the stroke prognosis) scores at 2-12 weeks after middle cerebral artery occlusion were [1, (1; 3)], [1, (1;2)], [1, (1; 1.5)] and [1, (1; 1.5)], respectively. The RMT and RMT lateralisation (AMC) were predictors of stroke prognosis, and the RMT lateralisation of PMN and latency of AMC were predictors of motor impairment. CONCLUSIONS Both upper motor neuron (UMN) and LMN pathway excitability is reduced after stroke, and structural damage in median nerve 12 weeks after stroke occur. In addition, RMT and RMT lateralisation are predictors of stroke prognosis and motor impairment.
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Affiliation(s)
- Pingping Li
- Department of Neurology and Stroke Center, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China,Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Chunyong Chen
- Department of Neurology and Stroke Center, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China,Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Baozi Huang
- Department of Neurology and Stroke Center, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China,Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Zimu Jiang
- Department of Neurology and Stroke Center, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jiating Wei
- Department of Neurology and Stroke Center, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jinsheng Zeng
- Department of Neurology and Stroke Center, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
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Vasin MV. B-190 (Indralin) in Light of the History of the Formation of Ideas about the Mechanism of Action of Radioprotectors. BIOL BULL+ 2022. [DOI: 10.1134/s1062359021110091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Vasin MV, Ushakov IB. An Analysis of the Role of Bioenergetic Processes under Radioprotective Effects Mediated by Alpha1-Adrenergic Agonists. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921030210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Obrador E, Salvador R, Villaescusa JI, Soriano JM, Estrela JM, Montoro A. Radioprotection and Radiomitigation: From the Bench to Clinical Practice. Biomedicines 2020; 8:E461. [PMID: 33142986 PMCID: PMC7692399 DOI: 10.3390/biomedicines8110461] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023] Open
Abstract
The development of protective agents against harmful radiations has been a subject of investigation for decades. However, effective (ideal) radioprotectors and radiomitigators remain an unsolved problem. Because ionizing radiation-induced cellular damage is primarily attributed to free radicals, radical scavengers are promising as potential radioprotectors. Early development of such agents focused on thiol synthetic compounds, e.g., amifostine (2-(3-aminopropylamino) ethylsulfanylphosphonic acid), approved as a radioprotector by the Food and Drug Administration (FDA, USA) but for limited clinical indications and not for nonclinical uses. To date, no new chemical entity has been approved by the FDA as a radiation countermeasure for acute radiation syndrome (ARS). All FDA-approved radiation countermeasures (filgrastim, a recombinant DNA form of the naturally occurring granulocyte colony-stimulating factor, G-CSF; pegfilgrastim, a PEGylated form of the recombinant human G-CSF; sargramostim, a recombinant granulocyte macrophage colony-stimulating factor, GM-CSF) are classified as radiomitigators. No radioprotector that can be administered prior to exposure has been approved for ARS. This differentiates radioprotectors (reduce direct damage caused by radiation) and radiomitigators (minimize toxicity even after radiation has been delivered). Molecules under development with the aim of reaching clinical practice and other nonclinical applications are discussed. Assays to evaluate the biological effects of ionizing radiations are also analyzed.
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Affiliation(s)
- Elena Obrador
- Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 46010 Valencia, Spain; (E.O.); (R.S.); (J.M.E.)
| | - Rosario Salvador
- Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 46010 Valencia, Spain; (E.O.); (R.S.); (J.M.E.)
| | - Juan I. Villaescusa
- Service of Radiological Protection, Clinical Area of Medical Image, La Fe University Hospital, 46026 Valencia, Spain;
- Biomedical Imaging Research Group GIBI230, Health Research Institute (IISLaFe), La Fe University Hospital, 46026 Valencia, Spain
| | - José M. Soriano
- Food & Health Lab, Institute of Materials Science, University of Valencia, 46980 Valencia, Spain;
- Joint Research Unit in Endocrinology, Nutrition and Clinical Dietetics, University of Valencia-Health Research Institute IISLaFe, 46026 Valencia, Spain
| | - José M. Estrela
- Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 46010 Valencia, Spain; (E.O.); (R.S.); (J.M.E.)
| | - Alegría Montoro
- Service of Radiological Protection, Clinical Area of Medical Image, La Fe University Hospital, 46026 Valencia, Spain;
- Biomedical Imaging Research Group GIBI230, Health Research Institute (IISLaFe), La Fe University Hospital, 46026 Valencia, Spain
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Abstract
Introduction: There are at the minimum two major, quite different approaches to advance drug discovery. The first being the target-based drug discovery (TBDD) approach that is commonly referred to as the molecular approach. The second approach is the phenotype-based drug discovery (PBDD), also known as physiology-based drug discovery or empirical approach. Area covered: The authors discuss, herein, the need for developing radiation countermeasure agents for various sub-syndromes of acute radiation syndromes (ARS) following TBDD and PBDD approaches. With time and continuous advances in radiation countermeasure drug development research, the expectation is to have multiple radiation countermeasure agents for each sub-syndrome made available to radiation exposed victims. Expert opinion: The majority of the countermeasures currently being developed for ARS employ the PBDD approach, while the TBDD approach is clearly under-utilized. In the future, an improved drug development strategy might be a 'hybrid' strategy that is more reliant on TBDD for the initial drug discovery via large-scale screening of potential candidate agents, while utilizing PBDD for secondary screening of those candidates, followed by tertiary analytics phase in order to pinpoint efficacious candidates that target the specific sub-syndromes of ARS.
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Affiliation(s)
- Vijay K Singh
- a Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine , Uniformed Services University of the Health Sciences , Bethesda , MD , USA.,b Scientific Research Department , Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences , Bethesda , MD , USA
| | | | - Ayodele O Olabisi
- b Scientific Research Department , Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences , Bethesda , MD , USA
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Abstract
Peroxiredoxin 6 (Prdx6) is a member of an evolutionary ancient family of peroxidase enzymes with diverse functions in the cell. Prdx6 is an important enzymatic antioxidant. It reduces a wide range of peroxide substrates in the cell, thus playing a leading role in the maintenance of the redox homeostasis in mammalian cells. Beside peroxidase activity, Prdx6 has been shown to possess an activity of phospholipase A2, an enzyme playing an important role in membrane phospholipid metabolism. Moreover, Prdx6 takes part in intercellular and intracellular signal transduction due to its peroxidase and phospholipase activity, thus facilitating the initiation of regenerative processes in the cell, suppression of apoptosis, and activation of cell proliferation. Being an effective and important antioxidant enzyme, Prdx6 plays an essential role in neutralizing oxidative stress caused by various factors, including action of ionizing radiation. Endogenous Prdx6 has been shown to possess a significant radioprotective potential in cellular and animal models. Moreover, intravenous infusion of recombinant Prdx6 to animals before irradiation at lethal or sublethal doses has shown its high radioprotective effect. Exogenous Prdx6 effectively alleviates the severeness of radiation lesions, providing normalization of the functional state of radiosensitive organs and tissues, and leads to a significant elevation of the survival rate of animals. Prdx6 can be considered as a potent and promising radioprotective agent for reducing the pathological effect of ionizing radiation on mammalian organisms. The radioprotective properties and mechanisms of radioprotective action of Prdx6 are discussed in the current review.
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Affiliation(s)
- Mars G Sharapov
- Laboratory of Mechanisms of Reception, Institute of Cell Biophysics of the Russian Academy of Sciences, 142290 Pushchino, Russia.
| | - Vladimir I Novoselov
- Laboratory of Mechanisms of Reception, Institute of Cell Biophysics of the Russian Academy of Sciences, 142290 Pushchino, Russia.
| | - Sergey V Gudkov
- Wave Research Center, Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia.
- Department of Experimental Clinical Studies, Moscow Regional Research and Clinical Institute (MONIKI), 129110 Moscow, Russia.
- The Institute of Biology and Biomedicine, Lobachevsky State University of Nizhni Novgorod, 603950 Nizhni Novgorod, Russia.
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Baklaushev VP, Durov OV, Kim SV, Gulaev EV, Gubskiy IL, Konoplyannikov MA, Zabozlaev FG, Zhang C, Agrba VZ, Orlov SV, Lapin BA, Troitskiy AV, Averyanov AV, Ahlfors JE. Development of a motor and somatosensory evoked potentials-guided spinal cord Injury model in non-human primates. J Neurosci Methods 2018; 311:200-214. [PMID: 30393204 DOI: 10.1016/j.jneumeth.2018.10.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 10/22/2018] [Indexed: 02/07/2023]
Abstract
Background Nonhuman primates (NHP) may provide the most adequate (in terms of neuroanatomy and neurophysiology) model of spinal cord injury (SCI) for testing regenerative therapies, but bioethical considerations exclude their use in severe SCI. New Method A reproducible model of SCI at the lower thoracic level has been developed in Rhesus macaques. The model comprises surgical resection of 25% of the spinal cord in the projection of the dorsal funiculus and dorsolateral corticospinal pathways, controlled via registration of intraoperative evoked potentials (EPs). The animals were evaluated using the modified Hindlimb score, MRI, SSEP, and MEP over a time period of 8-12 weeks post-SCI, followed by histological examination. Results Complete disappearance of intraoperative EPs from distal hindlimb muscles without restoration within two weeks post-SCI was an indicator for irreversible disruption of the abovementioned pathways. As a result, controlled damage to the spinal cord was achieved in three NHPs, clinically manifested as irreversible lower monoplegia. No significant functional restoration was observed in these NHPs up to 12 weeks post-SCI. Demyelination of the damaged ascending tracts was detected. Disturbances in pelvic organ function were not observed in all animals. Comparison with existing methods The new method of EPs-guided SCI allows a more controlled and irreversible damage to the spinal cord compared with contusion and other transection approaches. Conclusions This method to induce complete SCI in NHP is well tolerated, reproducible and ethically acceptable: these are valuable attributes in a preclinical model that will hopefully help advance testing of new regenerative therapies in SCI.
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Affiliation(s)
- V P Baklaushev
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia; Institute for Advanced Training, FMBA, Moscow, Russia.
| | - O V Durov
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - S V Kim
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - E V Gulaev
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - I L Gubskiy
- Research and Education Center for Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russia
| | - M A Konoplyannikov
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia; Institute of Regenerative Medicine, Sechenov Medical University, Moscow, Russia
| | - F G Zabozlaev
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - C Zhang
- Research and Education Center for Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russia; Department of Bone and Soft Tissue Tumors, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - V Z Agrba
- Institute of Medicinal Primatology Russian Academy of Science, Sochi, Russia
| | - S V Orlov
- Institute of Medicinal Primatology Russian Academy of Science, Sochi, Russia
| | - B A Lapin
- Institute of Medicinal Primatology Russian Academy of Science, Sochi, Russia
| | - A V Troitskiy
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia; Institute for Advanced Training, FMBA, Moscow, Russia
| | - A V Averyanov
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
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Singh VK, Garcia M, Seed TM. A review of radiation countermeasures focusing on injury-specific medicinals and regulatory approval status: part II. Countermeasures for limited indications, internalized radionuclides, emesis, late effects, and agents demonstrating efficacy in large animals with or without FDA IND status. Int J Radiat Biol 2017; 93:870-884. [DOI: 10.1080/09553002.2017.1338782] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Vijay K. Singh
- Division of Radioprotection, Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Melissa Garcia
- Division of Radioprotection, Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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Singh VK, Seed TM. A review of radiation countermeasures focusing on injury-specific medicinals and regulatory approval status: part I. Radiation sub-syndromes, animal models and FDA-approved countermeasures. Int J Radiat Biol 2017. [PMID: 28650707 DOI: 10.1080/09553002.2017.1332438] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE The increasing global risk of nuclear and radiological accidents or attacks has driven renewed research interest in developing medical countermeasures to potentially injurious exposures to acute irradiation. Clinical symptoms and signs of a developing acute radiation injury, i.e. the acute radiation syndrome, are grouped into three sub-syndromes named after the dominant organ system affected, namely the hematopoietic, gastrointestinal, and neurovascular systems. The availability of safe and effective countermeasures against the above threats currently represents a significant unmet medical need. This is the first article within a three-part series covering the nature of the radiation sub-syndromes, various animal models for radiation countermeasure development, and the agents currently approved by the United States Food and Drug Administration for countering the medical consequences of several of these prominent radiation exposure-associated syndromes. CONCLUSIONS From the U.S. and global perspectives, biomedical research concerning medical countermeasure development is quite robust, largely due to increased government funding following the 9/11 incidence and subsequent rise of terrorist-associated threats. A wide spectrum of radiation countermeasures for specific types of radiation injuries is currently under investigation. However, only a few radiation countermeasures have been fully approved by regulatory agencies for human use during radiological/nuclear contingencies. Additional research effort, with additional funding, clearly will be needed in order to fill this significant, unmet medical health problem.
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Affiliation(s)
- Vijay K Singh
- a Division of Radioprotection, Department of Pharmacology and Molecular Therapeutics , F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences , Bethesda , MD , USA.,b Armed Forces Radiobiology Research Institute , Uniformed Services University of the Health Sciences , Bethesda , MD , USA
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Abstract
INTRODUCTION Despite significant scientific advances over the past six decades toward the development of safe and effective radiation countermeasures for humans using animal models, only two pharmaceutical agents have been approved by United States Food and Drug Administration (US FDA) for hematopoietic acute radiation syndrome (H-ARS). Additional research efforts are needed to further develop large animal models for improving the prediction of clinical safety and effectiveness of radiation countermeasures for ARS and delayed effects of acute radiation exposure (DEARE) in humans. Area covered: The authors review the suitability of animal models for the development of radiation countermeasures for ARS following the FDA Animal Rule with a special focus on nonhuman primate (NHP) models of ARS. There are seven centers in the United States currently conducting studies with irradiated NHPs, with the majority of studies being conducted with rhesus monkeys. Expert opinion: The NHP model is considered the gold standard animal model for drug development and approval by the FDA. The lack of suitable substitutes for NHP models for predicting response in humans serves as a bottleneck for the development of radiation countermeasures. Additional large animal models need to be characterized to support the development and FDA-approval of new radiation countermeasures.
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Affiliation(s)
- Vijay K Singh
- a Department of Pharmacology and Molecular Therapeutics , F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences , Bethesda , MD , USA.,b Armed Forces Radiobiology Research Institute , Uniformed Services University of the Health Sciences , Bethesda , MD , USA
| | - Ayodele O Olabisi
- b Armed Forces Radiobiology Research Institute , Uniformed Services University of the Health Sciences , Bethesda , MD , USA
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Vasin MV, Ushakov IB. Comparative efficacy and the window of radioprotection for adrenergic and serotoninergic agents and aminothiols in experiments with small and large animals. J Radiat Res 2015; 56:1-10. [PMID: 25312329 PMCID: PMC4572585 DOI: 10.1093/jrr/rru087] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 08/25/2014] [Accepted: 09/05/2014] [Indexed: 06/04/2023]
Abstract
This review gives a comparative evaluation of the radioprotective properties and the therapeutic index (TI) of radioprotectors from various pharmacological group in experiments on both small and large animals. It presents a hypothesis explaining the decrease in the TI of cystamine and 5-methoxytryptamine (mexamine), and the retention of that of α1-adrenomimetic indralin, and also compares the effects on large and small animals. The considerable differences in the therapeutic indices of catecholamines, serotonin and cystamine are a consequence of specific features of their mechanisms of radioprotective action. Radioprotectors acting via receptor mediation tend to provide a more expanded window of protection. The reduction in the TI of cystamine in larger animals, such as dogs, may be caused by the greater increase in toxicity of aminothiols in relation to the decrease in their optimal doses for radioprotective effect in going from mice to dogs, which is a consequence of the slower metabolic processes in larger animals. The somatogenic phase of intoxication by cystamine is significantly longer than the duration of its radioprotective effect, and increases with irradiation. The decrease in the radioprotective effect and the TI of mexamine in experiments with dogs may be caused by their lower sensitivity to the acute hypoxia induced by the mexamine. This is because of lower gradient in oxygen tension between tissue cells and blood capillaries under acute hypoxia that is determined by lower initial oxygen consumption in a large animal as compared with a small animal. Indralin likely provides optimal radioprotective effects and a higher TI for large animals via the increased specificity of its adrenergic effect on tissue respiration, which supports the development of acute hypoxia in the radiosensitive tissues of large animals. The stimulatory effect of indralin on early post-irradiation haematopoietic recovery cannot provide a high level of radioprotective action for large animals, but it may promote recovery.
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Affiliation(s)
- Mikhail V Vasin
- State Scientific Center Russian Federation - Institute of Biomedical Problems, Russian Academy of Science, 76a Khoroshovskoe schuss, Moscow123007, Russia
| | - Igor B Ushakov
- State Scientific Center Russian Federation - Institute of Biomedical Problems, Russian Academy of Science, 76a Khoroshovskoe schuss, Moscow123007, Russia
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Vasin MV. Comments on the mechanisms of action of radiation protective agents: basis components and their polyvalence. Springerplus 2014; 3:414. [PMID: 25133093 PMCID: PMC4132458 DOI: 10.1186/2193-1801-3-414] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 07/31/2014] [Indexed: 12/18/2022]
Abstract
Purpose These comments suggest a division of radiation protective agents on the grounds of their mechanism of action that increase the radio resistance of an organism. Conclusion Given below is the division of radiation protective agents on the basis of their mechanism of action into 3 groups: 1) Radiation protective agents, with the implementation of radiation protective action taking place at the cellular level in the course of rapidly proceeding radiation-chemical reactions. At the same time, when the ionizing radiation energy is absorbed, these agents partially neutralize the “oxygen effect” as a radiobiological phenomenon, especially in the radiolysis of DNA; 2) Radiation protective agents that exert their effect at the system level by accelerating the post-radiation recovery of radiosensitive tissues through activation of a number of pro-inflammatory signaling pathways and an increase in the secretion of hematopoietic growth factors, including their use as mitigators in the early period after irradiation prior to the clinical development of acute radiation syndrome (ARS). 3) Radiomodulators including drugs and nutritional supplements that can elevate the resistance of the organism to adverse environmental factors, including exposure to ionization by means of modulating the gene expression through a hormetic effect of small doses of stressors and a “substrate” maintenance of adaptive changes, resulting in an increased antioxidant protection of the organism. Radiation protective agents having polyvalence in implementation of their action may simultaneously induce radioprotective effect by various routes with a prevalence of basis mechanisms of the action.
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Affiliation(s)
- Mikhail V Vasin
- Department of Medicine of Catastrophe, Russian Medical Academy of Post-Graduate Education, St. Polikarpova 10, 125284 Moscow, Russia
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