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Boerma M, Sridharan V, Mao XW, Nelson GA, Cheema AK, Koturbash I, Singh SP, Tackett AJ, Hauer-Jensen M. Effects of ionizing radiation on the heart. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 770:319-327. [PMID: 27919338 DOI: 10.1016/j.mrrev.2016.07.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 12/20/2022]
Abstract
This article provides an overview of studies addressing effects of ionizing radiation on the heart. Clinical studies have identified early and late manifestations of radiation-induced heart disease, a side effect of radiation therapy to tumors in the chest when all or part of the heart is situated in the radiation field. Studies in preclinical animal models have contributed to our understanding of the mechanisms by which radiation may injure the heart. More recent observations in human subjects suggest that ionizing radiation may have cardiovascular effects at lower doses than was previously thought. This has led to examinations of low-dose photons and low-dose charged particle irradiation in animal models. Lastly, studies have started to identify non-invasive methods for detection of cardiac radiation injury and interventions that may prevent or mitigate these adverse effects. Altogether, this ongoing research should increase our knowledge of biological mechanisms of cardiovascular radiation injury, identify non-invasive biomarkers for early detection, and potential interventions that may prevent or mitigate these adverse effects.
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Affiliation(s)
- Marjan Boerma
- University of Arkansas for Medical Sciences, Division of Radiation Health, Little Rock, AR, United States.
| | - Vijayalakshmi Sridharan
- University of Arkansas for Medical Sciences, Division of Radiation Health, Little Rock, AR, United States
| | - Xiao-Wen Mao
- Loma Linda University, Department of Basic Sciences, Loma Linda, CA, United States
| | - Gregory A Nelson
- Loma Linda University, Department of Basic Sciences, Loma Linda, CA, United States
| | - Amrita K Cheema
- Georgetown University Medical Center, Departments of Oncology and Biochemistry, Molecular and Cellular Biology, Washington, DC, United States
| | - Igor Koturbash
- University of Arkansas for Medical Sciences, Department of Environment and Occupational Health, Little Rock, AR, United States
| | - Sharda P Singh
- University of Arkansas for Medical Sciences, Department of Pharmacology and Toxicology, Little Rock, AR, United States
| | - Alan J Tackett
- University of Arkansas for Medical Sciences, Department of Biochemistry and Molecular Biology, Little Rock, AR, United States
| | - Martin Hauer-Jensen
- University of Arkansas for Medical Sciences, Division of Radiation Health, Little Rock, AR, United States; Central Arkansas Veterans Healthcare System, Surgical Service, Little Rock, AR, United States
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Singh VK, Hauer-Jensen M. γ-Tocotrienol as a Promising Countermeasure for Acute Radiation Syndrome: Current Status. Int J Mol Sci 2016; 17:E663. [PMID: 27153057 PMCID: PMC4881489 DOI: 10.3390/ijms17050663] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/03/2016] [Accepted: 04/25/2016] [Indexed: 01/13/2023] Open
Abstract
The hazard of ionizing radiation exposure due to nuclear accidents or terrorist attacks is ever increasing. Despite decades of research, still, there is a shortage of non-toxic, safe and effective medical countermeasures for radiological and nuclear emergency. To date, the U.S. Food and Drug Administration (U.S. FDA) has approved only two growth factors, Neupogen (granulocyte colony-stimulating factor (G-CSF), filgrastim) and Neulasta (PEGylated G-CSF, pegfilgrastim) for the treatment of hematopoietic acute radiation syndrome (H-ARS) following the Animal Efficacy Rule. Promising radioprotective efficacy results of γ-tocotrienol (GT3; a member of the vitamin E family) in the mouse model encouraged its further evaluation in the nonhuman primate (NHP) model. These studies demonstrated that GT3 significantly aided the recovery of radiation-induced neutropenia and thrombocytopenia compared to the vehicle controls; these results particularly significant after exposure to 5.8 or 6.5 Gray (Gy) whole body γ-irradiation. The stimulatory effect of GT3 on neutrophils and thrombocytes (platelets) was directly and positively correlated with dose; a 75 mg/kg dose was more effective compared to 37.5 mg/kg. GT3 was also effective against 6.5 Gy whole body γ-irradiation for improving neutrophils and thrombocytes. Moreover, a single administration of GT3 without any supportive care was equivalent, in terms of improving hematopoietic recovery, to multiple doses of Neupogen and two doses of Neulasta with full supportive care (including blood products) in the NHP model. GT3 may serve as an ultimate radioprotector for use in humans, particularly for military personnel and first responders. In brief, GT3 is a promising radiation countermeasure that ought to be further developed for U.S. FDA approval for the ARS indication.
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Affiliation(s)
- Vijay K Singh
- Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD 20889, USA.
| | - Martin Hauer-Jensen
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare Systems, Little Rock, AR 72205, USA.
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Minicucci M, Oliveira F, Santos P, Polegato B, Roscani M, Fernandes AA, Lustosa B, Paiva S, Zornoff L, Azevedo P. Pentoxifylline Attenuates Cardiac Remodeling Induced by Tobacco Smoke Exposure. Arq Bras Cardiol 2016; 106:396-403. [PMID: 27096523 PMCID: PMC4914004 DOI: 10.5935/abc.20160057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/19/2016] [Indexed: 12/25/2022] Open
Abstract
Background Tobacco smoke exposure is an important risk factor for cardiac remodeling.
Under this condition, inflammation, oxidative stress, energy metabolism
abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has
anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative
properties. Objective The present study tested the hypothesis that pentoxifylline would attenuate
cardiac remodeling induced by smoking. Methods Wistar rats were distributed in four groups: Control (C), Pentoxifylline
(PX), Tobacco Smoke (TS), and PX-TS. After two months, echocardiography,
invasive blood pressure measurement, biochemical, and histological studies
were performed. The groups were compared by two-way ANOVA with a
significance level of 5%. Results TS increased left atrium diameter and area, which was attenuated by PX. In
the isolated heart study, TS lowered the positive derivate (+dp/dt), and
this was attenuated by PX. The antioxidants enzyme superoxide dismutase and
glutathione peroxidase were decreased in the TS group; PX recovered these
activities. TS increased lactate dehydrogenase (LDH) and decreased
3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA) and citrate synthase (CS).
PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased
IL-10, ICAM-1, and caspase-3. PX did not influence these variables. Conclusion TS induced cardiac remodeling, associated with increased inflammation,
oxidative stress, apoptosis, and changed energy metabolism. PX attenuated
cardiac remodeling by reducing oxidative stress and improving cardiac
bioenergetics, but did not act upon cardiac cytokines and apoptosis.
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Affiliation(s)
- Marcos Minicucci
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Fernando Oliveira
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Priscila Santos
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Bertha Polegato
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Meliza Roscani
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Ana Angelica Fernandes
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Beatriz Lustosa
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Sergio Paiva
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Leonardo Zornoff
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
| | - Paula Azevedo
- Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP, Brazil
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Johnke RM, Sattler JA, Allison RR. Radioprotective agents for radiation therapy: future trends. Future Oncol 2015; 10:2345-57. [PMID: 25525844 DOI: 10.2217/fon.14.175] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Only two radioprotective compounds, amifostine and palifermin, currently have the US FDA approval for use in radiation therapy. However, several agents have been reported that show therapeutic promise. Many of these agents are free radical scavengers/antioxidants. Superoxide dismutase and superoxide dismutase mimetics, nitroxides and dietary antioxidants are all being investigated. Recently, alternative strategies of drug development have been evolving, which focus on targeting the series of cellular insult recognition/repair responses initiated following radiation. These agents, which include cytokines/growth factors, angiotensin-converting enzyme inhibitors and apoptotic modulators, show promise of having significant impact on the mitigation of radiation injury. Herein, we review current literature on the development of radioprotectors with emphasis on compounds with proven or potential usefulness in radiation therapy.
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Affiliation(s)
- Roberta M Johnke
- Department of Radiation Oncology, East Carolina University Brody School of Medicine, Greenville, NC 27834, USA
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Vitamin E Analogs as Radiation Response Modifiers. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:741301. [PMID: 26366184 PMCID: PMC4558447 DOI: 10.1155/2015/741301] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/06/2015] [Accepted: 07/22/2015] [Indexed: 02/07/2023]
Abstract
The potentially life-threatening effects of total body ionizing radiation exposure have been known for more than a century. Despite considerable advances in our understanding of the effects of radiation over the past six decades, efforts to identify effective radiation countermeasures for use in case of a radiological/nuclear emergency have been largely unsuccessful. Vitamin E is known to have antioxidant properties capable of scavenging free radicals, which have critical roles in radiation injuries. Tocopherols and tocotrienols, vitamin E analogs together known as tocols, have shown promise as radioprotectors. Although the pivotal mechanisms of action of tocols have long been thought to be their antioxidant properties and free radical scavenging activities, other alternative mechanisms have been proposed to drive their activity as radioprotectors. Here we provide a brief overview of the effects of ionizing radiation, the mechanistic mediators of radiation-induced damage, and the need for radiation countermeasures. We further outline the role for, efficacy of, and mechanisms of action of tocols as radioprotectors, and we compare and contrast their efficacy and mode of action with that of another well-studied chemical radioprotector, amifostine.
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56
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Lieblong BJ, Sridharan V, Srivastava AK, Moros EG, Sharma SK, Boerma M. Role of the bradykinin B2 receptor in a rat model of local heart irradiation. Int J Radiat Biol 2015; 91:634-42. [PMID: 25955317 DOI: 10.3109/09553002.2015.1047041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE Radiation-induced heart disease (RIHD) is a delayed effect of radiotherapy for cancers of the chest, such as breast, esophageal, and lung. Kinins are small peptides with cardioprotective properties. We previously used a rat model that lacks the precursor kininogen to demonstrate that kinins are involved in RIHD. Here, we examined the role of the kinin B2 receptor (B2R) in early radiation-induced signaling in the heart. MATERIALS AND METHODS Male Brown Norway rats received the B2R-selective antagonist HOE-140 (icatibant) via osmotic minipump from 5 days before until 4 weeks after 21 Gy local heart irradiation. At 4 weeks, signaling events were measured in left ventricular homogenates and nuclear extracts using western blotting and real-time polymerase chain reaction. Numbers of CD68-positive (monocytes/macrophages), CD2-positive (T-lymphocytes), and mast cells were measured using immunohistochemistry. RESULTS Radiation-induced c-Jun phosphorylation and nuclear translocation were enhanced by HOE-140. HOE-140 did not modify endothelial nitric oxide synthase (eNOS) phosphorylation or alter numbers of CD2-positive or mast cells, but enhanced CD68-positive cell counts in irradiated hearts. CONCLUSIONS B2R signaling may regulate monocyte/macrophage infiltration and c-Jun signals in the irradiated heart. Although eNOS is a main target for kinins, the B2R may not regulate eNOS phosphorylation in response to radiation.
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Affiliation(s)
- Benjamin J Lieblong
- a Department of Pharmacology and Toxicology , University of Arkansas for Medical Sciences , Little Rock, Arkansas , USA
| | - Vijayalakshmi Sridharan
- b Division of Radiation Health, Department of Pharmaceutical Sciences , University of Arkansas for Medical Sciences , Little Rock, Arkansas , USA
| | - Anup K Srivastava
- a Department of Pharmacology and Toxicology , University of Arkansas for Medical Sciences , Little Rock, Arkansas , USA
| | - Eduardo G Moros
- c Moffitt Cancer Center and Research Institute , Department of Radiation Oncology , Tampa, Florida , USA
| | - Sunil K Sharma
- b Division of Radiation Health, Department of Pharmaceutical Sciences , University of Arkansas for Medical Sciences , Little Rock, Arkansas , USA
| | - Marjan Boerma
- b Division of Radiation Health, Department of Pharmaceutical Sciences , University of Arkansas for Medical Sciences , Little Rock, Arkansas , USA
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Slezak J, Kura B, Ravingerová T, Tribulova N, Okruhlicova L, Barancik M. Mechanisms of cardiac radiation injury and potential preventive approaches. Can J Physiol Pharmacol 2015; 93:737-53. [PMID: 26030720 DOI: 10.1139/cjpp-2015-0006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In addition to cytostatic treatment and surgery, the most common cancer treatment is gamma radiation. Despite sophisticated radiological techniques however, in addition to irradiation of the tumor, irradiation of the surrounding healthy tissue also takes place, which results in various side-effects, depending on the absorbed dose of radiation. Radiation either damages the cell DNA directly, or indirectly via the formation of oxygen radicals that in addition to the DNA damage, react with all cell organelles and interfere with their molecular mechanisms. The main features of radiation injury besides DNA damage is inflammation and increased expression of pro-inflammatory genes and cytokines. Endothelial damage and dysfunction of capillaries and small blood vessels plays a particularly important role in radiation injury. This review is focused on summarizing the currently available data concerning the mechanisms of radiation injury, as well as the effectiveness of various antioxidants, anti-inflammatory cytokines, and cytoprotective substances that may be utilized in preventing, mitigating, or treating the toxic effects of ionizing radiation on the heart.
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Affiliation(s)
- Jan Slezak
- Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic.,Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic
| | - Branislav Kura
- Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic.,Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic
| | - Táňa Ravingerová
- Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic.,Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic
| | - Narcisa Tribulova
- Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic.,Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic
| | - Ludmila Okruhlicova
- Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic.,Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic
| | - Miroslav Barancik
- Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic.,Institute for Heart Research, Slovak Academy of Sciences, Dúbravská cesta 9, 842 33 Bratislava, Slovak Republic
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Sharma S, Moros EG, Boerma M, Sridharan V, Han EY, Clarkson R, Hauer-Jensen M, Corry PM. A novel technique for image-guided local heart irradiation in the rat. Technol Cancer Res Treat 2014; 13:593-603. [PMID: 24000983 PMCID: PMC3951712 DOI: 10.7785/tcrtexpress.2013.600256] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/28/2013] [Accepted: 01/30/2013] [Indexed: 11/06/2022] Open
Abstract
In radiotherapy treatment of thoracic, breast and chest wall tumors, the heart may be included (partially or fully) in the radiation field. As a result, patients may develop radiation-induced heart disease (RIHD) several years after exposure to radiation. There are few methods available to prevent or reverse RIHD and the biological mechanisms remain poorly understood. In order to further study the effects of radiation on the heart, we developed a model of local heart irradiation in rats using an image-guided small animal conformal radiation therapy device (SACRTD) developed at our institution. First, Monte Carlo based simulations were used to design an appropriate collimator. EBT-2 films were used to measure relative dosimetry, and the absolute dose rate at the isocenter was measured using the AAPM protocol TG-61. The hearts of adult male Sprague-Dawley rats were irradiated with a total dose of 21 Gy. For this purpose, rats were anesthetized with isoflurane and placed in a custom-made vertical rat holder. Each heart was irradiated with a 3-beam technique (one AP field and 2 lateral fields), with each beam delivering 7 Gy. For each field, the heart was visualized with a digital flat panel X-ray imager and placed at the isocenter of the 1.8 cm diameter beam. In biological analysis of radiation exposure, immunohistochemistry showed γH2Ax foci and nitrotyrosine throughout the irradiated hearts but not in the lungs. Long-term follow-up of animals revealed histopathological manifestations of RIHD, including myocardial degeneration and fibrosis. The results demonstrate that the rat heart irradiation technique using the SACRTD was successful and that surrounding untargeted tissues were spared, making this approach a powerful tool for in vivo radiobiological studies of RIHD. Functional and structural changes in the rat heart after local irradiation are ongoing.
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Affiliation(s)
- Sunil Sharma
- Department of Radiation Oncology, Radiation Oncology Center, University of Arkansas for Medical _Sciences, Little Rock, AR .
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Abstract
AbstractThe Growth Differentiation Factor-15 gene (GDF15) is a member of TGF-b superfamily and this cytokine family is considered to be a promising target for cancer therapy. The purpose of this study was to investigate the effect of tumor derived GDF15 on proliferation and radiosensitivity of breast cancer cells in vitro and in vivo. A mouse breast cancer LM2 cell line with stable transfection of full-length mouse GDF15 cDNA was established. Cell growth and proliferation was observed using WST assay and impedance-based method. Radiation induced GDF15 and TGF-b1 expression was determined by qRT-PCR. Radiosensitivity was measured by a colony formation assay in vitro and by a tumor growth delay assay in vivo. Cells with more than a 10-fold increase in GDF15 expression had a higher growth rate than parental control cells in vitro and in vivo. The radiation induced elevation of the expression of TGFb1 was reduced in GDF15 overexpressing cells. GDF15 may play a role in the radiation response of breast cancer cells by effecting cell survival, inhibiting radiation-induced cell death, and inhibiting the TGF-b1 related cytotoxic action.
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Moulder JE. 2013 Dade W. Moeller lecture: medical countermeasures against radiological terrorism. HEALTH PHYSICS 2014; 107:164-71. [PMID: 24978287 PMCID: PMC4076685 DOI: 10.1097/hp.0000000000000082] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Soon after the 9-11 attacks, politicians and scientists began to question our ability to cope with a large-scale radiological terrorism incident. The outline of what was needed was fairly obvious: the ability to prevent such an attack, methods to cope with the medical consequences, the ability to clean up afterward, and the tools to figure out who perpetrated the attack and bring them to justice. The medical response needed three components: the technology to determine rapidly the radiation doses received by a large number of people, methods for alleviating acute hematological radiation injuries, and therapies for mitigation and treatment of chronic radiation injuries. Research done to date has shown that a realistic medical response plan is scientifically possible, but the regulatory and financial barriers to achieving this may currently be insurmountable.
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Affiliation(s)
- John E. Moulder
- Center for Medical Countermeasures Against Radiological Terrorism, Radiation Oncology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin, 53226 U. S. A
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Benderitter M, Caviggioli F, Chapel A, Coppes RP, Guha C, Klinger M, Malard O, Stewart F, Tamarat R, van Luijk P, Limoli CL. Stem cell therapies for the treatment of radiation-induced normal tissue side effects. Antioxid Redox Signal 2014; 21:338-55. [PMID: 24147585 PMCID: PMC4060814 DOI: 10.1089/ars.2013.5652] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Targeted irradiation is an effective cancer therapy but damage inflicted to normal tissues surrounding the tumor may cause severe complications. While certain pharmacologic strategies can temper the adverse effects of irradiation, stem cell therapies provide unique opportunities for restoring functionality to the irradiated tissue bed. RECENT ADVANCES Preclinical studies presented in this review provide encouraging proof of concept regarding the therapeutic potential of stem cells for treating the adverse side effects associated with radiotherapy in different organs. Early-stage clinical data for radiation-induced lung, bone, and skin complications are promising and highlight the importance of selecting the appropriate stem cell type to stimulate tissue regeneration. CRITICAL ISSUES While therapeutic efficacy has been demonstrated in a variety of animal models and human trials, a range of additional concerns regarding stem cell transplantation for ameliorating radiation-induced normal tissue sequelae remain. Safety issues regarding teratoma formation, disease progression, and genomic stability along with technical issues impacting disease targeting, immunorejection, and clinical scale-up are factors bearing on the eventual translation of stem cell therapies into routine clinical practice. FUTURE DIRECTIONS Follow-up studies will need to identify the best possible stem cell types for the treatment of early and late radiation-induced normal tissue injury. Additional work should seek to optimize cellular dosing regimes, identify the best routes of administration, elucidate optimal transplantation windows for introducing cells into more receptive host tissues, and improve immune tolerance for longer-term engrafted cell survival into the irradiated microenvironment.
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Affiliation(s)
- Marc Benderitter
- 1 Laboratory of Radiopathology and Experimental Therapies, IRSN , PRP-HOM, SRBE, Fontenay-aux-Roses, France
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Gu J, Liu K, Li H, Wang X, Yang K. Astragalus saponin attenuates the expression of fibrosis-related molecules in irradiated cardiac fibroblasts. Acta Biochim Biophys Sin (Shanghai) 2014; 46:492-501. [PMID: 24739634 DOI: 10.1093/abbs/gmu021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The main pathological change of radiation-induced heart disease is fibrosis. Emerging evidence has indicated that Astragalus membranaceus and its extractant, Astragalus saponin (AST), were used for treating fibrosis diseases. In the present study, the effects of AST on fibrosis damage induced by irradiation were determined. After being irradiated with 1 or 2-Gy X-rays, obvious changes of endoplasmic reticulum morphology were observed in cardiac fibroblasts (CFs), suggesting that its protein processing function was imbalanced, which indirectly indicated that fibrosis damage was caused by irradiating CFs. The expression levels of TGF-β1 and collagen I (Col-1) were increased at 48-h post-irradiation. Administration of 20 μg/ml AST reduced the production of reactive oxygen species in irradiated CFs and decreased the expression of Col-1, TGF-β1, and p-Smad2/3. Polymerase chain reaction (PCR)-array analysis showed that there were ~30 genes which were mainly classified into extracellular matrix, remodeling enzymes, inflammatory cytokines/chemokines, and TGF-β superfamily, were up-regulated after treatment with 1-Gy X-ray, whereas most of these genes were down-regulated when pretreated with 20 μg/ml of AST. In addition, TIMP1 and Smad7 genes that were down-regulated after treatment with 1-Gy X-ray were up-regulated when pretreated with 20 μg/ml of AST. In conclusion, radiation-induced fibrosis damage was observed at a cellular level. AST attenuated this fibrosis damage effect in irradiated CFs and this anti-fibrosis effect may be closely related to its antioxidant action. The involvement of fibrosis-related molecules in irradiated CFs was systematically demonstrated by a PCR array for the first time. AST reversed the expression of the majority of genes changed by irradiation, which further confirmed its anti-fibrosis effect.
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Affiliation(s)
- Jing Gu
- Evidence-Based Medicine Center, Institute of Integrated Traditional Chinese and Western Medicine, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China Gansu University of Traditional Chinese Medicine, Lanzhou 730000, China Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province, Lanzhou 730000, China
| | - Kai Liu
- Gansu University of Traditional Chinese Medicine, Lanzhou 730000, China
| | - Hailong Li
- Gansu University of Traditional Chinese Medicine, Lanzhou 730000, China
| | - Xiaogang Wang
- Evidence-Based Medicine Center, Institute of Integrated Traditional Chinese and Western Medicine, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Kehu Yang
- Evidence-Based Medicine Center, Institute of Integrated Traditional Chinese and Western Medicine, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province, Lanzhou 730000, China
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63
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Singh VK, Beattie LA, Seed TM. Vitamin E: tocopherols and tocotrienols as potential radiation countermeasures. JOURNAL OF RADIATION RESEARCH 2013; 54:973-88. [PMID: 23658414 PMCID: PMC3823775 DOI: 10.1093/jrr/rrt048] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Despite the potential devastating health consequences of intense total-body irradiation, and the decades of research, there still remains a dearth of safe and effective radiation countermeasures for emergency, radiological/nuclear contingencies that have been fully approved and sanctioned for use by the US FDA. Vitamin E is a well-known antioxidant, effective in scavenging free radicals generated by radiation exposure. Vitamin E analogs, collectively known as tocols, have been subject to active investigation for a long time as radioprotectors in patients undergoing radiotherapy and in the context of possible radiation accidents or terrorism scenarios. Eight major isoforms comprise the tocol group: four tocopherols and four tocotrienols. A number of these agents and their derivatives are being investigated actively as radiation countermeasures using animal models, and several appear promising. Although the tocols are well recognized as potent antioxidants and are generally thought to mediate radioprotection through 'free radical quenching', recent studies have suggested several alternative mechanisms: most notably, an 'indirect effect' of tocols in eliciting specific species of radioprotective growth factors/cytokines such as granulocyte colony-stimulating factor (G-CSF). The radioprotective efficacy of at least two tocols has been abrogated using a neutralizing antibody of G-CSF. Based on encouraging results of radioprotective efficacy, laboratory testing of γ-tocotrienol has moved from a small rodent model to a large nonhuman primate model for preclinical evaluation. In this brief review we identify and discuss selected tocols and their derivatives currently under development as radiation countermeasures, and attempt to describe in some detail their in vivo efficacy.
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Affiliation(s)
- Vijay K. Singh
- Radiation Countermeasures Program, Scientific Research Department, Armed Forces Radiobiology Research Institute, 8901 Wisconsin Ave, Bethesda, MD 20889-5603, USA
- Department of Radiation Biology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Corresponding author. Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, 8901 Wisconsin Ave, Bethesda, MD 20889-5603, USA. Tel: +1-301-295-2347; Fax: +1-301-295-6503;
| | - Lindsay A. Beattie
- Radiation Countermeasures Program, Scientific Research Department, Armed Forces Radiobiology Research Institute, 8901 Wisconsin Ave, Bethesda, MD 20889-5603, USA
| | - Thomas M. Seed
- Tech Micro Services, 4417 Maple Avenue, Bethesda, MD, USA
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Wondergem J, Boerma M, Kodama K, Stewart FA, Trott KR. Cardiovascular effects after low-dose exposure and radiotherapy: what research is needed? RADIATION AND ENVIRONMENTAL BIOPHYSICS 2013; 52:425-434. [PMID: 23999657 DOI: 10.1007/s00411-013-0489-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 08/19/2013] [Indexed: 06/02/2023]
Abstract
The authors of this report met at the Head Quarter of the International Atomic Energy Agency (IAEA) in Vienna, Austria, on 2-4 July 2012, for intensive discussions of an abundance of original publications on new epidemiological studies on cardiovascular effects after low-dose exposure and radiotherapy and radiobiological experiments as well as several comprehensive reviews that were published since the previous meeting by experts sponsored by the IAEA in June 2006. The data necessitated a re-evaluation of the situation with special emphasis on the consequences current experimental and clinical data may have for clinical oncology/radiotherapy and radiobiological research. The authors jointly arrived at the conclusions and recommendations presented here.
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Affiliation(s)
- Jan Wondergem
- Applied Radiation Biology and Radiotherapy Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagrammer Strasse 5, PO box 100, 1400, Vienna, Austria,
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Giardi MT, Touloupakis E, Bertolotto D, Mascetti G. Preventive or potential therapeutic value of nutraceuticals against ionizing radiation-induced oxidative stress in exposed subjects and frequent fliers. Int J Mol Sci 2013; 14:17168-92. [PMID: 23965979 PMCID: PMC3759958 DOI: 10.3390/ijms140817168] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 08/01/2013] [Accepted: 08/12/2013] [Indexed: 12/19/2022] Open
Abstract
Humans are constantly exposed to ionizing radiation deriving from outer space sources or activities related to medical care. Absorption of ionizing radiation doses over a prolonged period of time can result in oxidative damage and cellular dysfunction inducing several diseases, especially in ageing subjects. In this report, we analyze the effects of ionizing radiation, particularly at low doses, in relation to a variety of human pathologies, including cancer, and cardiovascular and retinal diseases. We discuss scientific data in support of protection strategies by safe antioxidant formulations that can provide preventive or potential therapeutic value in response to long-term diseases that may develop following exposure.
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Affiliation(s)
| | - Eleftherios Touloupakis
- Biosensor, Via Olmetti 44 Formello, Rome 00060, Italy; E-Mail:
- Department of Chemistry, University of Crete, P.O. Box 2208, Voutes-Heraklion 71003, Greece
| | - Delfina Bertolotto
- Agenzia Spaziale Italiana (ASI), Viale Liegi 26, Rome 00198, Italy; E-Mails: (D.B.); (G.M.)
| | - Gabriele Mascetti
- Agenzia Spaziale Italiana (ASI), Viale Liegi 26, Rome 00198, Italy; E-Mails: (D.B.); (G.M.)
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Lenarczyk M, Lam V, Jensen E, Fish BL, Su J, Koprowski S, Komorowski RA, Harmann L, Migrino RQ, Li XA, Hopewell JW, Moulder JE, Baker JE. Cardiac injury after 10 gy total body irradiation: indirect role of effects on abdominal organs. Radiat Res 2013; 180:247-58. [PMID: 23919311 DOI: 10.1667/rr3292.1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The objective of this study was to determine whether radiation-induced injury to the heart after 10 Gy total body irradiation (TBI) is direct or indirect. Young male WAG/RijCmcr rats received a 10 Gy single dose using TBI, upper hemi-body (UHB) irradiation, lower hemi-body (LHB) irradiation, TBI with the kidneys shielded or LHB irradiation with the intestines shielded. Age-matched, sham-irradiated rats served as controls. The lipid profile, kidney injury, heart and liver morphology and cardiac function were determined up to 120 days after irradiation. LHB, but not UHB irradiation, increased the risk factors for cardiac disease as well as the occurrence of cardiac and kidney injury in a way that was quantitatively and qualitatively similar to that observed after TBI. Shielding of the kidneys prevented the increases in risk factors for cardiac disease. Shielding of the intestines did not prevent the increases in risk factors for cardiac disease. There was no histological evidence of liver injury 120 days after irradiation. Injury to the heart from irradiation appears to be indirect, supporting the notion that injury to abdominal organs, principally the kidneys, is responsible for the increased risk factors for and the occurrence of cardiac disease after TBI and LHB irradiation.
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Sridharan V, Tripathi P, Sharma S, Corry PM, Moros EG, Singh A, Compadre CM, Hauer-Jensen M, Boerma M. Effects of late administration of pentoxifylline and tocotrienols in an image-guided rat model of localized heart irradiation. PLoS One 2013; 8:e68762. [PMID: 23894340 PMCID: PMC3718790 DOI: 10.1371/journal.pone.0068762] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 06/02/2013] [Indexed: 01/15/2023] Open
Abstract
Radiation-induced heart disease (RIHD) is a long-term side effect of radiotherapy of intrathoracic, chest wall and breast tumors when radiation fields encompass all or part of the heart. Previous studies have shown that pentoxifylline (PTX) in combination with α-tocopherol reduced manifestations of RIHD in rat models of local heart irradiation. The relative contribution of PTX and α-tocopherol to these beneficial effects are not known. This study examined the effects of PTX alone or in combination with tocotrienols, forms of vitamin E with potential potent radiation mitigation properties. Rats received localized X-irradiation of the heart with an image-guided irradiation technique. At 3 months after irradiation rats received oral treatment with vehicle, PTX, or PTX in combination with a tocotrienol-enriched formulation. At 6 months after irradiation, PTX-treated rats showed arrhythmia in 5 out of 14 animals. PTX alone or in combination with tocotrienols did not alter cardiac radiation fibrosis, left ventricular protein expression of the endothelial markers von Willebrand factor and neuregulin-1, or phosphorylation of the signal mediators Akt, Erk1/2, or PKCα. On the other hand, tocotrienols reduced cardiac numbers of mast cells and macrophages, but enhanced the expression of tissue factor. While this new rat model of localized heart irradiation does not support the use of PTX alone, the effects of tocotrienols on chronic manifestations of RIHD deserve further investigation.
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Affiliation(s)
- Vijayalakshmi Sridharan
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Preeti Tripathi
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Sunil Sharma
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Peter M. Corry
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Eduardo G. Moros
- Department of Radiation Oncology, Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Awantika Singh
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Cesar M. Compadre
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Martin Hauer-Jensen
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- Surgical Service, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, United States of America
| | - Marjan Boerma
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
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Stewart FA, Seemann I, Hoving S, Russell NS. Understanding radiation-induced cardiovascular damage and strategies for intervention. Clin Oncol (R Coll Radiol) 2013; 25:617-24. [PMID: 23876528 DOI: 10.1016/j.clon.2013.06.012] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/26/2013] [Accepted: 06/30/2013] [Indexed: 12/22/2022]
Abstract
There is a clear association between therapeutic doses of thoracic irradiation and an increased risk of cardiovascular disease (CVD) in cancer survivors, although these effects may take decades to become symptomatic. Long-term survivors of Hodgkin's lymphoma and childhood cancers have two-fold to more than seven-fold increased risks for late cardiac deaths after total tumour doses of 30-40 Gy, given in 2 Gy fractions, where large volumes of heart were included in the field. Increased cardiac mortality is also seen in women irradiated for breast cancer. Breast doses are generally 40-50 Gy in 2 Gy fractions, but only a small part of the heart is included in the treatment fields and mean heart doses rarely exceeded 10-15 Gy, even with older techniques. The relative risks of cardiac mortality (1.1-1.4) are consequently lower than for Hodgkin's lymphoma survivors. Some epidemiological studies show increased risks of cardiac death after accidental or environmental total body exposures to much lower radiation doses. The mechanisms whereby these cardiac effects occur are not fully understood and different mechanisms are probably involved after high therapeutic doses to the heart, or part of the heart, than after low total body exposures. These various mechanisms probably result in different cardiac pathologies, e.g. coronary artery atherosclerosis leading to myocardial infarct, versus microvascular damage and fibrosis leading to congestive heart failure. Experimental studies can help to unravel some of these mechanisms and may identify suitable strategies for managing or inhibiting CVD. In this overview, the main epidemiological and clinical evidence for radiation-induced CVD is summarised. Experimental data shedding light on some of the underlying pathologies and possible targets for intervention are also discussed.
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Affiliation(s)
- F A Stewart
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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69
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Hamama S, Gilbert-Sirieix M, Vozenin MC, Delanian S. Radiation-induced enteropathy: Molecular basis of pentoxifylline–vitamin E anti-fibrotic effect involved TGF-β1 cascade inhibition. Radiother Oncol 2012; 105:305-12. [DOI: 10.1016/j.radonc.2012.08.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 07/23/2012] [Accepted: 08/28/2012] [Indexed: 01/03/2023]
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Abstract
Radiation-induced heart disease (RIHD) is a serious side effect of radiotherapy for intrathoracic and chest wall tumors. The threshold dose for development of clinically significant RIHD is believed to be lower than previously assumed. Therefore, research into mechanisms of RIHD has gained substantial momentum. RIHD becomes clinically apparent ten to fifteen years after radiation exposure. Chronic manifestations of RIHD include accelerated atherosclerosis, cardiomyopathy, and valve abnormalities. Reducing exposure of the heart during radiotherapy is the only known method of preventing RIHD, and there are no approaches to reverse RIHD once it occurs. We use a combination of pharmacological and genetic animal models to determine biological mechanisms of RIHD. Major technological advances in small animal research have made this type of study more valuable. The long-term goal of this work is to identify targets for intervention in RIHD, thereby enhancing the efficacy and safety of thoracic radiotherapy.
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Affiliation(s)
- Marjan Boerma
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansass
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71
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Hamama S, Delanian S, Monceau V, Vozenin MC. Therapeutic management of intestinal fibrosis induced by radiation therapy: from molecular profiling to new intervention strategies et vice et versa. FIBROGENESIS & TISSUE REPAIR 2012; 5:S13. [PMID: 23259677 PMCID: PMC3368760 DOI: 10.1186/1755-1536-5-s1-s13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Chronic toxicities of locoregional and systemic oncological treatments commonly develop in long-term cancer survivors. Amongst these toxicities, post-radiotherapeutic complications alter patient's quality of life. Reduction of exposure of normal tissues can be achieved by optimization of radiotherapy. Furthermore, understanding of the fibrogenic mechanisms has provided targets to prevent, mitigate, and reverse late radiation-induced damages. This mini-review shows how (i) global molecular studies using gene profiling can provide tools to develop new intervention strategies and (ii) how successful clinical trials, conducted in particular with combined pentoxifylline-vitamin E, can take benefice of biological and molecular evidences to improve our understanding of fibrogenic mechanisms, enhance the robustness of proposed treatments, and lead ultimately to better treatments for patient's benefice.
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Affiliation(s)
- Saad Hamama
- INSERM U-1030 "Molecular Radiotherapy" Institut Gustave Roussy, Villejuif, France ; "Molecular Radiotherapy", Université Paris Sud Paris XI, France
| | - Sylvie Delanian
- INSERM U-1030 "Molecular Radiotherapy" Institut Gustave Roussy, Villejuif, France ; "Molecular Radiotherapy", Université Paris Sud Paris XI, France ; Unité de Radiopathologie, Service Oncologie-Radiothérapie, Hôpital Saint-Louis, APHP, Paris, France
| | - Virginie Monceau
- INSERM U-1030 "Molecular Radiotherapy" Institut Gustave Roussy, Villejuif, France
| | - Marie-Catherine Vozenin
- INSERM U-1030 "Molecular Radiotherapy" Institut Gustave Roussy, Villejuif, France ; "Molecular Radiotherapy", Université Paris Sud Paris XI, France
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72
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Houser SR, Margulies KB, Murphy AM, Spinale FG, Francis GS, Prabhu SD, Rockman HA, Kass DA, Molkentin JD, Sussman MA, Koch WJ. Animal models of heart failure: a scientific statement from the American Heart Association. Circ Res 2012; 111:131-50. [PMID: 22595296 DOI: 10.1161/res.0b013e3182582523] [Citation(s) in RCA: 331] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Sardaro A, Petruzzelli MF, D'Errico MP, Grimaldi L, Pili G, Portaluri M. Radiation-induced cardiac damage in early left breast cancer patients: risk factors, biological mechanisms, radiobiology, and dosimetric constraints. Radiother Oncol 2012; 103:133-42. [PMID: 22391054 DOI: 10.1016/j.radonc.2012.02.008] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 01/30/2012] [Accepted: 02/04/2012] [Indexed: 01/29/2023]
Abstract
Today there is general awareness of the potential damage to the heart in left-sided (more than in right-sided) breast cancer radiotherapy (RT). Historical changes in tumor and heart doses are presented here along with the impact of different RT techniques and volumes. Individual and pharmacological risk factors are also examined with respect to radiation damage. The biological mechanisms of harm are only partially understood, such as the radiobiology of heart damage due to the presence of various radiosensitive structures and their topographic heterogeneity. Furthermore, individual variability may expose patients to higher or lower risks of late cardiac damage or death. Damage mechanisms and radiobiological characteristics in heart irradiation are presented in relation to dosimetric and biological parameters.
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Affiliation(s)
- Angela Sardaro
- University Institute of Radiation Oncology Policlinico di Bari, Italy
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Berbée M, Hauer-Jensen M. Novel drugs to ameliorate gastrointestinal normal tissue radiation toxicity in clinical practice: what is emerging from the laboratory? Curr Opin Support Palliat Care 2012; 6:54-9. [PMID: 22228028 PMCID: PMC3677768 DOI: 10.1097/spc.0b013e32834e3bd7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW To give an overview of promising novel agents under development for the prevention and reduction of gastrointestinal radiation injury. RECENT FINDINGS Currently, several novel agents are being tested as drugs to prevent or reduce gastrointestinal radiation injury. These drugs may not only prevent injury, but also mitigate toxicity, that is, reduce injury after radiation exposure has occurred. Promising novel agents include the somatostatin analogue SOM230, growth factors, agents acting on the toll-like receptor 5 pathway, endothelial protectants, and the vitamin E analogue γ-tocotrienol. SUMMARY Gastrointestinal radiation injury is the most important dose-limiting factor during radiotherapy of the abdomen or pelvis. It may severely affect the quality of life both during radiotherapy treatment and in cancer survivors. To date, there are no agents that can prevent or reduce intestinal radiation injury. Hence, there is an urgent need for the development of novel drugs to ameliorate intestinal toxicity during and after radiotherapy. This review summarizes the several agents that have been shown to reduce intestinal radiation injury in animals. Further research is needed to investigate their safety and efficacy in patients receiving radiotherapy for abdominal or pelvic tumours.
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Affiliation(s)
- Maaike Berbée
- Department of Radiation Oncology (Maastro), GROW Research Institute, Maastricht University Medical Center, Maastricht, The Netherlands.
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75
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Stewart FA, Akleyev AV, Hauer-Jensen M, Hendry JH, Kleiman NJ, Macvittie TJ, Aleman BM, Edgar AB, Mabuchi K, Muirhead CR, Shore RE, Wallace WH. ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context. Ann ICRP 2012; 41:1-322. [PMID: 22925378 DOI: 10.1016/j.icrp.2012.02.001] [Citation(s) in RCA: 795] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.
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Levy A, Chargari C. Pentoxifylline to avoid radiation-induced cardiotoxicity: from NF-κB to beyond--a reply to M. Halle and P. Hall and P. Tornvall. J Intern Med 2011; 270:487-8. [PMID: 21848916 DOI: 10.1111/j.1365-2796.2011.02440.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Nowak G, Bakajsova D, Hayes C, Hauer-Jensen M, Compadre CM. γ-Tocotrienol protects against mitochondrial dysfunction and renal cell death. J Pharmacol Exp Ther 2011; 340:330-8. [PMID: 22040679 DOI: 10.1124/jpet.111.186882] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Oxidative stress is a major mechanism of a variety of renal diseases. Tocopherols and tocotrienols are well known antioxidants. This study aimed to determine whether γ-tocotrienol (GT3) protects against mitochondrial dysfunction and renal proximal tubular cell (RPTC) injury caused by oxidants. Primary cultures of RPTCs were injured by using tert-butyl hydroperoxide (TBHP) in the absence and presence of GT3 or α-tocopherol (AT). Reactive oxygen species (ROS) production increased 300% in TBHP-injured RPTCs. State 3 respiration, oligomycin-sensitive respiration, and respiratory control ratio (RCR) decreased 50, 63, and 47%, respectively. The number of RPTCs with polarized mitochondria decreased 54%. F₀F₁-ATPase activity and ATP content decreased 31 and 65%, respectively. Cell lysis increased from 3% in controls to 26 and 52% at 4 and 24 h, respectively, after TBHP exposure. GT3 blocked ROS production, ameliorated decreases in state 3 and oligomycin-sensitive respirations and F₀F₁-ATPase activity, and maintained RCR and mitochondrial membrane potential (ΔΨ(m)) in injured RPTCs. GT3 maintained ATP content, blocked RPTC lysis at 4 h, and reduced it to 13% at 24 h after injury. Treatment with equivalent concentrations of AT did not block ROS production and cell lysis and moderately improved mitochondrial respiration and coupling. This is the first report demonstrating the protective effects of GT3 against RPTC injury by: 1) decreasing production of ROS, 2) improving mitochondrial respiration, coupling, ΔΨ(m), and F₀F₁-ATPase function, 3) maintaining ATP levels, and 4) preventing RPTC lysis. Our data suggest that GT3 is superior to AT in protecting RPTCs against oxidant injury and may prove therapeutically valuable for preventing renal injury associated with oxidative stress.
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Affiliation(s)
- Grazyna Nowak
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, 4301 West Markham St., MS 522-3, Little Rock, AR 72205, USA.
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Abstract
Abstract population are ubiquitous background radiation and medical exposure of patients. From the early 1980s to 2006, the average dose per individual in the United States for all sources of radiation increased by a factor of 1.7-6.2 mSv, with this increase due to the growth of medical imaging procedures. Radiation can place individuals at an increased risk of developing cardiovascular disease. Excess risk of cardiovascular disease occurs a long time after exposure to lower doses of radiation as demonstrated in Japanese atomic bomb survivors. This review examines sources of radiation (atomic bombs, radiation accidents, radiological terrorism, cancer treatment, space exploration, radiosurgery for cardiac arrhythmia, and computed tomography) and the risk for developing cardiovascular disease. The evidence presented suggests an association between cardiovascular disease and exposure to low-to-moderate levels of radiation, as well as the well-known association at high doses. Studies are needed to define the extent that diagnostic and therapeutic radiation results in increased risk factors for cardiovascular disease, to understand the mechanisms involved, and to develop strategies to mitigate or treat radiation-induced cardiovascular disease.
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Affiliation(s)
- John E Baker
- Division of Cardiothoracic Surgery, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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Complete Restoration of Refractory Mandibular Osteoradionecrosis by Prolonged Treatment with a Pentoxifylline-Tocopherol-Clodronate Combination (PENTOCLO): A Phase II Trial. Int J Radiat Oncol Biol Phys 2011; 80:832-9. [DOI: 10.1016/j.ijrobp.2010.03.029] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 02/08/2010] [Accepted: 03/10/2010] [Indexed: 11/22/2022]
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81
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Boerma M, Hauer-Jensen M. Potential targets for intervention in radiation-induced heart disease. Curr Drug Targets 2011; 11:1405-12. [PMID: 20583977 DOI: 10.2174/1389450111009011405] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Accepted: 04/05/2010] [Indexed: 12/14/2022]
Abstract
Radiotherapy of thoracic and chest wall tumors, if all or part of the heart was included in the radiation field, can lead to radiation-induced heart disease (RIHD), a late and potentially severe side effect. RIHD presents clinically several years after irradiation and manifestations include accelerated atherosclerosis, pericardial and myocardial fibrosis, conduction abnormalities, and injury to cardiac valves. The pathogenesis of RIHD is largely unknown, and a treatment is not available. Hence, ongoing pre-clinical studies aim to elucidate molecular and cellular mechanisms of RIHD. Here, an overview of recent pre-clinical studies is given, and based on the results of these studies, potential targets for intervention in RIHD are discussed.
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Affiliation(s)
- M Boerma
- Department of Pharmaceutical Sciences, Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
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Berbee M, Fu Q, Boerma M, Pathak R, Zhou D, Kumar KS, Hauer-Jensen M. Reduction of radiation-induced vascular nitrosative stress by the vitamin E analog γ-tocotrienol: evidence of a role for tetrahydrobiopterin. Int J Radiat Oncol Biol Phys 2011; 79:884-91. [PMID: 20950957 PMCID: PMC3023840 DOI: 10.1016/j.ijrobp.2010.08.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 08/19/2010] [Accepted: 08/20/2010] [Indexed: 01/13/2023]
Abstract
PURPOSE The vitamin E analog γ-tocotrienol (GT3) is a powerful radioprotector. GT3 reduces postradiation vascular peroxynitrite production, an effect dependent on inhibition of hydroxy-methylglutaryl-coenzyme A reductase. Hydroxy-methylglutaryl-coenzyme A reductase inhibitors mediate their pleiotropic effects via endothelial nitric oxide synthase that requires the cofactor tetrahydrobiopterin (BH4). This study investigated the effects of radiation on BH4 bioavailability and of GT3 on BH4 metabolism. METHODS AND MATERIALS Mice were exposed to 8.5 Gy of total body irradiation (TBI). Lung BH4 and total biopterin concentrations were measured 0, 3.5, 7, 14, and 21 days after TBI by use of differential oxidation followed by high-performance liquid chromatography. The effect of exogenous GT3 and BH4 treatment on postradiation vascular oxidative stress and bone marrow colony-forming units were assessed in vivo. The effect of GT3 on endothelial cell apoptosis and endothelial expression of guanosine triphosphate (GTP) cyclohydrolase 1 (GTPCH), GTPCH feedback regulatory protein (GFRP), GFRP transcription, GFRP protein levels, and GFRP-GTPCH protein binding was determined in vitro. RESULTS Compared with baseline levels, lung BH4 concentrations decreased by 24% at 3.5 days after TBI, an effect that was reversed by GT3. At 14 and 21 days after TBI, compensatory increases in BH4 (58% and 80%, respectively) were observed. Relative to vehicle-treated controls, both GT3 and BH4 supplementation reduced postirradiation vascular peroxynitrite production at 3.5 days (by 66% and 33%, respectively), and BH4 resulted in a 68% increase in bone marrow colony-forming units. GT3 ameliorated endothelial cell apoptosis and reduced endothelial GFRP protein levels and GFRP-GTPCH binding by decreasing transcription of the GFRP gene. CONCLUSIONS BH4 bioavailability is reduced in the early postradiation phase. Exogenous administration of BH4 reduces postirradiation vascular oxidative stress. GT3 potently reduces the expression of GFRP, one of the key regulatory proteins in the BH4 pathway, and may thus exert some of its beneficial effects on postradiation free radical production partly by counteracting the decrease in BH4.
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Affiliation(s)
- Maaike Berbee
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Qiang Fu
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Marjan Boerma
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Rupak Pathak
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Daohong Zhou
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - K. Sree Kumar
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD
| | - Martin Hauer-Jensen
- University of Arkansas for Medical Sciences, Little Rock, AR
- Central Arkansas Veterans Healthcare System, Little Rock, AR
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83
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Berbée M, Fu Q, Garg S, Kulkarni S, Kumar KS, Hauer-Jensen M. Pentoxifylline enhances the radioprotective properties of γ-tocotrienol: differential effects on the hematopoietic, gastrointestinal and vascular systems. Radiat Res 2010; 175:297-306. [PMID: 21388273 DOI: 10.1667/rr2399.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The vitamin E analog γ-tocotrienol (GT3) is a potent radioprotector and mitigator. This study was performed to (a) determine whether the efficacy of GT3 can be enhanced by the addition of the phosphodiesterase inhibitor pentoxifylline (PTX) and (b) to obtain information about the mechanism of action. Mice were injected subcutaneously with vehicle, GT3 [400 mg/kg 24 h before total-body irradiation (TBI)], PTX (200 mg/kg 30 min before TBI), or GT3+PTX before being exposed to 8.5-13 Gy TBI. Overall lethality, survival time and intestinal, hematopoietic and vascular injury were assessed. Cytokine levels in the bone marrow microenvironment were measured, and the requirement for endothelial nitric oxide synthase (eNOS) was studied in eNOS-deficient mice. GT3+PTX significantly improved survival compared to GT3 alone and provided full protection against lethality even after exposure to 12.5 Gy. GT3+PTX improved bone marrow CFUs, spleen colony counts and platelet recovery compared to GT3 alone. GT3 and GT3+PTX increased bone marrow plasma G-CSF levels as well as the availability of IL-1α, IL-6 and IL-9 in the early postirradiation phase. GT3 and GT3+PTX were equally effective in ameliorating intestinal injury and vascular peroxynitrite production. Survival studies in eNOS-deficient mice and appropriate controls revealed that eNOS was not required for protection against lethality after TBI. Combined treatment with GT3 and PTX increased postirradiation survival over that with GT3 alone by a mechanism that may depend on induction of hematopoietic stimuli. GT3+PTX did not reduce GI toxicity or vascular oxidative stress compared to GT3 alone. The radioprotective effect of either drug alone or both drugs in combination does not require the presence of eNOS.
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Affiliation(s)
- Maaike Berbée
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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84
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Boerma M, Hauer-Jensen M. Preclinical research into basic mechanisms of radiation-induced heart disease. Cardiol Res Pract 2010; 2011:858262. [PMID: 20953374 PMCID: PMC2952915 DOI: 10.4061/2011/858262] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 09/04/2010] [Indexed: 01/20/2023] Open
Abstract
Radiation-induced heart disease (RIHD) is a potentially severe side effect of radiotherapy of thoracic and chest wall tumors if all or part of the heart was included in the radiation field. RIHD presents clinically several years after irradiation and manifestations include accelerated atherosclerosis, pericardial and myocardial fibrosis, conduction abnormalities, and injury to cardiac valves. There is no method to prevent or reverse these injuries when the heart is exposed to ionizing radiation. This paper presents an overview of recent studies that address the role of microvascular injury, endothelial dysfunction, mast cells, and the renin angiotensin system in animal models of cardiac radiation injury. These insights into the basic mechanisms of RIHD may lead to the identification of targets for intervention in this late radiotherapy side effect.
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Affiliation(s)
- M. Boerma
- Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 522-10, Little Rock, AR 72205, USA
| | - M. Hauer-Jensen
- Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 522-10, Little Rock, AR 72205, USA
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85
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Andratschke N, Maurer J, Molls M, Trott KR. Late radiation-induced heart disease after radiotherapy. Clinical importance, radiobiological mechanisms and strategies of prevention. Radiother Oncol 2010; 100:160-6. [PMID: 20826032 DOI: 10.1016/j.radonc.2010.08.010] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 07/06/2010] [Accepted: 08/12/2010] [Indexed: 12/14/2022]
Abstract
The clinical importance of radiation-induced heart disease, in particular in post-operative radiotherapy of breast cancer patients, has been recognised only recently. There is general agreement, that a co-ordinated research effort would be needed to explore all the potential strategies of how to reduce the late risk of radiation-induced heart disease in radiotherapy. This approach would be based, on one hand, on a comprehensive understanding of the radiobiological mechanisms of radiation-induced heart disease after radiotherapy which would require large-scale long-term animal experiments with high precision local heart irradiation. On the other hand - in close co-operation with mechanistic in vivo research studies - clinical studies in patients need to determine the influence of dose distribution in the heart on the risk of radiation-induced heart disease. The aim of these clinical studies would be to identify the critical structures within the organ which need to be spared and their radiation sensitivity as well as a potential volume and dose effect. The results of the mechanistic studies might also provide concepts of how to modify the gradual progression of radiation damage in the heart by drugs or biological molecules. The results of the studies in patients would need to also incorporate detailed dosimetric and imaging studies in order to develop early indicators of impending radiation-induced heart disease which would be a pre-condition to develop sound criteria for treatment plan optimisation.
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Affiliation(s)
- Nicolaus Andratschke
- Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie, Technische Universität München, Munich, Germany.
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86
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Zhang XD, Hou JF, Qin XJ, Li WL, Chen HL, Liu R, Liang X, Hai CX. Pentoxifylline inhibits intercellular adhesion molecule-1 (ICAM-1) and lung injury in experimental phosgene-exposure rats. Inhal Toxicol 2010; 22:889-95. [DOI: 10.3109/08958378.2010.493900] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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87
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Darby SC, Cutter DJ, Boerma M, Constine LS, Fajardo LF, Kodama K, Mabuchi K, Marks LB, Mettler FA, Pierce LJ, Trott KR, Yeh ETH, Shore RE. Radiation-related heart disease: current knowledge and future prospects. Int J Radiat Oncol Biol Phys 2010; 76:656-65. [PMID: 20159360 PMCID: PMC3910096 DOI: 10.1016/j.ijrobp.2009.09.064] [Citation(s) in RCA: 438] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/03/2009] [Accepted: 09/09/2009] [Indexed: 02/07/2023]
Abstract
The heart has traditionally been considered a radio-resistant organ that would be unaffected by cardiac doses below about 30 Gray. During the last few years, however, evidence that radiation-related heart disease can occur following lower doses has emerged from several sources. These include studies of breast cancer patients, who received mean cardiac doses of 3–17 Gray when given radiotherapy following surgery, and studies of survivors of the atomic bombings of Japan who received doses of up to 4 Gray. At doses above 30 Gray, radiation-related heart disease may occur within a year or two of exposure and risk increases with higher radiotherapy dose, younger age at irradiation, and the presence of conventional risk factors. At lower doses the typical latent period is much longer and is often more than a decade. However, the nature and magnitude of the risk following lower doses is not well characterized, and it is not yet clear whether there is a threshold dose below which there is no risk. The evidence regarding radiation-related heart disease comes from several different disciplines. The present review brings together information from pathology, radiobiology, cardiology, radiation oncology and epidemiology. It summarises current knowledge, identifies gaps in that knowledge, and outlines some potential strategies for filling them. Further knowledge about the nature and magnitude of radiation-related heart disease would have immediate application in radiation oncology. It would also provide a basis for radiation protection policies for use in diagnostic radiology and occupational exposure.
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Affiliation(s)
- Sarah C Darby
- Clinical Trial Service Unit, Richard Doll Building, Roosevelt Drive, Oxford, United Kingdom.
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88
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89
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de Souza RBC, Macedo AR, Kuruma KA, Macedo PA, Borges CTL. Pentoxyphylline in association with vitamin E reduces cutaneous fibrosis in systemic sclerosis. Clin Rheumatol 2009; 28:1207-12. [PMID: 19468787 DOI: 10.1007/s10067-009-1202-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2008] [Revised: 03/16/2009] [Accepted: 05/11/2009] [Indexed: 11/29/2022]
Abstract
Systemic sclerosis (SSc) is a disorder characterized by skin thickness and vasculopathy. The objective of the study was to evaluate the therapeutic effect and safety of the association of pentoxyphylline and vitamin E in SSc patients. Twelve SSc patients (American College of Rheumatology criteria) enrolled this 24-week open-label study. Patients received daily 800 mg of pentoxyphylline and 800 UI of vitamin E and were evaluated at 4-week interval. The primary efficacy endpoint was the change in Modified Rodnan Skin Score (MRSS) at week 24. Nine diffuse SSc patients treated 6 months with cyclophosphamide were used as a historical control group. The mean age of the treated group was 43.6 years, and ten of 12 (84%) patients were women. Their mean MRSS reduced from 25.7 to 18.7 (p = 0.03) at 16th week and remained significantly reduced throughout the study. In contrast, only a trend of MRSS reduction was observed in the historical control group (p = 0.06). Two patients started the study with active ischemic ulcers and ended with a complete healing of them. No serious side effects were reported. Pentoxyphylline and vitamin E might be an alternative therapeutic approach in SSc patients.
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Affiliation(s)
- Romy Beatriz Christmann de Souza
- Rheumatology Division, Medical School, University of São Paulo, Av. Dr. Arnaldo 455, 30 andar, São Paulo, SP, 01246-903, Brazil.
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90
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Berbée M, Fu Q, Boerma M, Wang J, Kumar KS, Hauer-Jensen M. gamma-Tocotrienol ameliorates intestinal radiation injury and reduces vascular oxidative stress after total-body irradiation by an HMG-CoA reductase-dependent mechanism. Radiat Res 2009; 171:596-605. [PMID: 19580495 PMCID: PMC2713014 DOI: 10.1667/rr1632.1] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Analogs of vitamin E (tocols) are under development as radioprophylactic agents because of their high efficacy and lack of toxicity. Gamma-tocotrienol (GT3) is of particular interest because, in addition to being an antioxidant, it also inhibits 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and accumulates to greater extent in endothelial cells than other tocols. We addressed in vivo whether HMG-CoA reductase inhibition contributes to the radioprotection conferred by GT3. Groups of mice were treated with vehicle, mevalonate (the product of the reaction catalyzed by HMG-CoA reductase), GT3 alone or GT3 in combination with mevalonate. Lethality and standard parameters of injury to the hematopoietic, intestinal and vascular/endothelial systems were assessed after exposure to total-body irradiation. GT3 improved postirradiation survival and decreased radiation-induced vascular oxidative stress, an effect that was reversible by mevalonate. GT3 also enhanced hematopoietic recovery, reduced intestinal radiation injury, and accelerated the recovery of soluble markers of endothelial function. These parameters were not reversed by mevalonate co-administration. Our data confirm GT3's radioprophylactic properties against hematopoietic injury and, for the first time, demonstrate benefits in terms of protection against gastrointestinal and vascular injury. The radioprotective efficacy of GT3 against vascular injury is related to its properties as an HMG-CoA reductase inhibitor.
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Affiliation(s)
- Maaike Berbée
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Qiang Fu
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Marjan Boerma
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Junru Wang
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - K. Sree Kumar
- Armed Forces Radiobiology Research Institute, Uniformed Services University, Bethesda, Maryland
| | - Martin Hauer-Jensen
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Departments of Surgery and Pathology, University of Arkansas for Medical Sciences and Surgery Service, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas
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91
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François A, Milliat F, Jullien N, Blirando K, Abderrahmani R, Benderitter M. [Radiotherapy: what therapeutic orientations against the digestive aftereffects?]. Med Sci (Paris) 2009; 25:267-72. [PMID: 19361390 DOI: 10.1051/medsci/2009253267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Despite constant progress in radiotherapy techniques such as tumour imaging and cartography, techniques of radiation delivery or fractionation schedules, damage to normal gastro-intestinal tissues is inevitably associated with radiation therapy of pelvic tumours. Acute radiation enteritis concerns 80% of patients. It is related to stem cell loss, default in epithelial regenerating capacity and inflammation-induced mucosal dystrophy and ulceration. Chronic injury may develop in 5 to 10% of patients and is characterized by intestinal wall fibrosis resulting from an exaggerated scarring process, chronic inflammation and tissue necrosis. Research in mechanistic processes of normal tissue damage paved the way for new therapeutic approaches to emerge. These new targets include mucosal regeneration, reduction of vascular activation, inflammation and thrombosis, and fight against mesenchymal cells sustained activation. Effective strategies are multiple on preclinical models, but numerous efforts have to be made to achieve the complicated goal of protection of normal tissues from the side effects of radiation therapy.
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Affiliation(s)
- Agnès François
- Institut de Radioprotection et de Sûreté Nucléaire, 31, avenue de la Division Leclerc, 92260 Fontenay-aux-Roses, France.
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