Molecular markers of radiation-related normal tissue toxicity

Protective Effects of Alpha Lipoic Acid Against Ionizing Radiation- Induced Hepatotoxicity in Rats

OBJECTIVE

Radiation is used to treat cancer but causes serious complications, such as liver toxicity. In this study, the protective effects of alpha lipoic acid against the unwanted effects of radiation used in many cancer treatments which can cause damage after treatment were investigated.

MATERIAL AND METHODS

The sample consisted of 32 Sprague-Dawley male rats randomized equally into 4 groups. The control group received no intervention. The alpha lipoic acid group was administered 50 mg/kg (dissolved in 0.9% NaCl) for 3 days. The ionizing radiation group was exposed to a total of 30 Gy radiation in 10 Gy fractions per day. The ionizing radiation+alpha lipoic acid group was administered 50 mg/kg alpha lipoic acid® prior to exposure to a total of 30 Gy radiation in 10 Gy fractions per day. Rats were sacrificed by cervical dislocation, and the liver was removed for histopathological studies and superoxide dismutase and malondialdehyde assays. Liver tissues were histopathologically assessed using hematoxylin-eosin staining after 4 weeks of the experiment.

RESULTS

The ionizing radiation + alpha lipoic acid group had significantly less severe necrosis than the ionizing radiation group. Compared to the ionizing radiation group and the ionizing radiation + alpha lipoic acid group, superoxide dismutase enzyme activity was decreased with the addition of alpha lipoic acid. In addition, when the amount of malondialdehyde, which is a marker of oxidative stress, was examined, it was determined that the amount of malondialdehyde in the ionizing radiation + alpha lipoic acid group was lower than in the ionizing radiation Group.

CONCLUSION

Alpha lipoic acid® mitigates radiotherapy-induced damage in liver tissue.

Severity scoring systems for radiation-induced GI injury - Prioritization for use of GI-ARS medical countermeasures

PURPOSE

Severity scoring systems for ionizing radiation-induced gastrointestinal injury have been used in animal radiation models, human studies involving the use of radiation therapy, and radiation accidents. Various radiation exposure scenarios (i.e., total body irradiation, total abdominal irradiation, etc.) have been used to investigate ionizing radiation-induced gastrointestinal injury. These radiation-induced GI severity scoring systems are based on clinical signs and symptoms and gastrointestinal-specific biomarkers (i.e., citrulline, etc.). In addition, the time course for radiation-induced changes in blood citrulline levels were compared across various animal (i.e., mice, minipigs, Rhesus Macaque, etc.) and human model systems.

CONCLUSIONS

A worksheet tool was developed to prioritize individuals with severe life-threatening gastrointestinal acute radiation syndrome, based on the design of the Exposure and Symptom Tool addressing hematopoietic acute radiation syndrome, to rescue individuals from potential gastrointestinal acute radiation syndrome injury. This tool provides a triage diagnostic approach to assist first-responders to assess individuals suspected of showing gastrointestinal acute radiation syndrome severity to guide medical management, hence enhancing medical readiness for managing radiological casualties.

Hepatotoxicity and renal toxicity induced by radiation and the protective effect of quercetin in male albino rats

PURPOSE

Although radiation is one of the basic methods commonly used in cancer treatment, it inevitably enters the field of treatment in healthy tissues and is adversely affected by the acute and chronic side effects of radiation. This study evaluated the possible protective effects of quercetin, an antioxidant agent, against liver and kidney damage in rats exposed to a whole-body single dose of radiation (10 Gy of gamma-ray).

MATERIALS AND METHODS

The study groups were formed as control, sham, quercetin, radiation, quercetin + radiation and radiation + quercetin using 60 male Wistar albino (200-250 g, 3 months old) rats, including 10 rats in each group. The gamma-ray provided by the Co60 teletherapy machine was given to the whole body as external irradiation. According to the groups, quercetin was administered to rats at 50 mg/kg/day via oral gavage before or after radiation administration. The rats were sacrificed the day after irradiation and the extracted tissue samples from all groups were compared histologically and immunohistochemically. DNA damage was determined by the neutral comet assay technique. Also, malondialdehyde (MDA) and glutathione peroxidase (GSH) were evaluated in liver and kidney tissues by the ELISA method.

RESULTS

Histopathological changes were observed altered morphology of liver and kidney tissues in the radiation groups. Sinusoidal dilatations, vacuolization, and hepatic parenchyma necrosis in the liver, while in kidneys, glomerular shrinkage, widened Bowman's space, tubular dilatation, and inflammation were evident. TNF-α, IL1-α, HIF1-α, and caspase 3 immunoreactivities in tissues were determined by immunohistochemistry. High caspase 3 positive cell number confirmed apoptosis, the comet parameters were decreased in the quercetin + radiation group. When compared to the control group, the exposure to radiation showed a marked elevation in MDA which was accompanied by high GSH. This damage was reduced in the quercetin + radiation group.

CONCLUSIONS

With the results obtained from the study; Quercetin is thought to have a protective potential against radiation-induced liver and kidney damage due to its radioprotective effect.

Clinical Applications of Biological Dosimetry in Patients Exposed to Low Dose Radiation Due to Radiological, Imaging or Nuclear Medicine Procedures

Radiation dosimetric biomarkers have found applications beyond radiation protection area and now are actively introduced into clinical practice. Cytogenetic assays appeared to be a valuable tool for individualized quantifying radiation effects in patients, with high capability for assessing genotoxicity of various medical exposure modalities and providing meaningful radiation dose estimates for prognoses of radiation-related cancer risk. This review summarized current data on the use of biological dosimetry methods in patients undergoing various medical irradiations to low doses. The highlighted topics include basic aspects of biological dosimetry and its limitations in the range of low radiation doses, and main patterns of in vivo induction of radiation biomarkers in clinical exposure scenarios, occurring in X-ray diagnostics, computed tomography, interventional radiology, low dose radiotherapy, and nuclear medicine (internally administered ¹³¹I and other radiopharmaceuticals). Additionally, several specific issues, examined by biodosimetry techniques, are analysed, such as contrast media effect, radiation response in pediatric patients, impact of magnetic resonance imaging, evaluation of radioprotectors, detection of patients' abnormal intrinsic radiosensitivity and dose estimation in persons involved in medical radiation incidents. A prognosis of possible directions for further improvements in this area includes the automation of cytogenetic analysis, introduction of molecular biodosimeters and development of multiparametric biodosimetry platforms. A potential approach to the advanced biodosimetry of internal exposure and/or low dose external irradiation is suggested; this can be a multiparametric platform based on the combination of the γ-H2AX foci, dicentric, and translocation assays, each applied in the optimum postexposure time range, with the amalgamation of the dose estimates. The study revealed the necessity of further research, which might clarify medical radiation safety concerns for patients via using stringent biodosimetry methodology.

Gastrointestinal Toxicity of Pelvic Radiotherapy: Are We Letting Women Down?

For all cancers there are four areas of importance: prevention, early diagnosis, optimising therapy and living with and beyond. For women diagnosed with gynaecological cancers, progress in these first three areas has been immense. However, living with and beyond has largely been ignored as a significant issue. As a group, patients treated for gynaecological cancer are more often young and more often suffer the most difficult long-term issues. Despite the growing number of long-term survivors, little has been done to ensure appropriate assessment and treatment of side-effects of cancer therapies, especially when radiotherapy has been used. For many affected patients their symptoms become part of everyday life, 'normality' is adjusted and these changes are tolerated even when severely limiting activities. Data show that even expert clinicians frequently do not appreciate the true impact of these problems and the focus of treatment and of follow-up remains fixed on 5-year survival and cancer recurrence, respectively. Many clinicians are unaware of what experts can do for toxicity and do not know where to refer their patients. However, rapid identification of patients with significant symptoms can lead to earlier diagnosis of treatable pathologies and improvement in patients' quality of life. In addition, the underlying pathophysiology of radiation-induced damage is potentially amenable to disease-modifying therapies. This review focuses on the factors that contribute to patients developing pelvic radiation disease, what can be done to mitigate the toxicity of treatment and highlights the challenges that must be addressed to reduce the gastrointestinal toxicity of pelvic radiotherapy.

Longitudinal metabolic alterations in plasma of rats exposed to low doses of high linear energy transfer radiation

Astronauts embarking on deep space missions are at high risk of long-term exposure to low doses of high linear energy transfer (LET) radiation, which can contribute to the development of cancer and multiple degenerative diseases. However, long term effects of exposure to low doses of high LET radiation in plasma metabolite profiles have not been elucidated. We utilized an untargeted metabolomics and lipidomics approach to analyze plasma obtained from adult male Long Evans rats to determine the longitudinal effects of low-dose proton and low-dose oxygen ion whole-body irradiation on metabolic pathways. Our findings reveal that radiation exposure induced modest changes in the metabolic profiles in plasma, 7 months after exposure. Furthermore, we identified some common metabolite dysregulations between protons and oxygen ions, which may indicate a similar mechanism of action for both radiation types.

Identifying Circulating and Lung Tissue Cytokines Associated with Thoracic Irradiation and AEOL 10150 Treatment in a Nonhuman Primate Model

Inflammatory cytokines have been suggested to play important roles in radiation-induced lung injury (RILI). Identifying significantly changed circulating and tissue cytokines after thoracic irradiation will aid in deciphering the mechanism of RILI and identifying potential biomarkers to predict clinical outcome. Herein, the levels of 24 cytokines were measured in serial plasma samples and lung tissue samples collected from a pilot study where nonhuman primates (NHPs) received 11.5 Gy whole thoracic lung irradiation (WTLI) and were then treated with or without a medical countermeasure, AEOL 10150 [a superoxide dismutase (SOD) mimetic]. Seven plasma cytokines (i.e., IP-10, MCP-1, IL-12, IL-15, IL-16, IL-7 and IL-6) were found to be significantly changed at different time points due to WTLI. Plasma IP-10 and MDC were significantly changed between the vehicle group and the drug group. The levels of IP-10, MCP-1, MIP-1α, TARC, IL-17, TNF-β and IL-6 were significantly elevated in the lung tissue lysates of NHPs that received WTLI versus radiation-naïve NHPs. The terminal plasma concentrations of IP-10, MDC, TARC, IL-12, IL-15 and IL-6 were significantly correlated with their levels in the lung tissue. The levels of four cytokines (MCP-4, IL-17, TNF-β and IL-2) at early time points (≤8 weeks postirradiation) were significantly correlated with their terminal plasma levels, respectively. Statistical analysis indicated that circulating cytokines could be discriminatory predictors of AEOL 10150 treatment. Taken together, our data suggested that the cytokine profiles were significantly changed after WTLI as well as mitigator treatment, and that the plasma cytokine profiles could potentially be used to distinguish vehicle or mitigator treatment after WTLI in a NHP model.

Evaluation of cytokine expression and circulating immune cell subsets as potential parameters of acute radiation toxicity in prostate cancer patients

One of the challenges of radiation oncology in the era of personalized medicine is identification of biomarkers associated with individual radiosensitivity. The aim of research was to evaluate the possible clinical value of the associations between clinical, physical, and biological factors, and risk for development of acute radiotoxicity in patients with prostate cancer. The study involved forty four patients treated with three-dimensional conformal radiotherapy. The concentrations of IL-1β, IL-2, IL-6, IFN-γ and TGF-β1 were assessed before radiotherapy, after 5th, 15th and 25th radiotherapy fractions, at the end, and 1 month after the end of radiotherapy. Cytokine gene expression was determined in peripheral blood mononuclear cells. The univariate analysis of circulating cytokine levels during radiotherapy showed that increased serum concentrations of IL-6 were significantly associated with higher grade of acute genitourinary toxicity. The multivariate analysis demonstrated that increased level of IL-6 during the radiotherapy was significantly associated with higher grade of acute genitourinary toxicity across treatment. TGF-β expression levels significantly decreased during course of radiotherapy. Research indicates that changes in circulating cytokine levels might be important parameter of radiotoxicity in patients with prostate cancer. These findings suggest that future studies based on multi-parameter examination are necessary for prediction of individual radiosensitivity.

Identification of Plasma Lipidome Changes Associated with Low Dose Space-Type Radiation Exposure in a Murine Model

Long-term exposures to low dose space radiation may have adverse effects on human health during missions in deep space. Conventional dosimetry, monitoring of prodromal symptoms, and peripheral lymphocyte counts are of limited value as biomarkers of organ- and tissue-specific radiation injury, particularly of injuries that appear weeks or months after radiation exposure. To assess the feasibility of using plasma metabolic and lipidomic profiles as biomarkers of injury from space radiation, we used a mouse model of exposure to low doses of oxygen ions (¹⁶O) and protons (¹H). Plasma profiles were compared with those of mice exposed to γ-rays as a reference set. Our results demonstrate major changes in glycerophospholipid metabolism, amino acid metabolism, as well as fatty acid metabolism. We also observed dyslipidemia and lipid peroxidation, suggesting an inflammatory phenotype with possible long-term consequences to overall health upon exposure to low doses of high linear energy transfer (LET) radiation.

Micronucleus Assay: The State of Art, and Future Directions

During almost 40 years of use, the micronucleus assay (MN) has become one of the most popular methods to assess genotoxicity of different chemical and physical factors, including ionizing radiation-induced DNA damage. In this minireview, we focus on the position of MN among the other genotoxicity tests, its usefulness in different applications and visibility by international organizations, such as International Atomic Energy Agency, Organization for Economic Co-operation and Development and International Organization for Standardization. In addition, the mechanism of micronuclei formation is discussed. Finally, foreseen directions of the MN development are pointed, such as automation, buccal cells MN and chromothripsis phenomenon.

CLINICAL APPLICATIONS OF BIOMARKERS OF RADIATION EXPOSURE: LIMITATIONS AND POSSIBLE SOLUTIONS THROUGH COORDINATED RESEARCH

Dosimetric biomarkers have been effectively and intensively used for a long time in the area of radiation protection. In contrast to that, no robust standards or widely accepted protocols for application of these end-points in radiotherapy, diagnostic and interventional radiology and nuclear medicine exist to date. The International Atomic Energy Agency (IAEA) organized the review of the available data on the possibilities of the use of dosimetric biomarkers in medical irradiation scenarios. The resultant Technical Report also contains a summary of identified problems, gaps in knowledge, limitations in methodology and recommendations for their overcoming. This work provided a conceptual background for the initiation of a new IAEA Coordinated Research Project E35010, MEDBIODOSE (2017-21), which is aimed specifically at the development and improvement of applications of biodosimetric markers in clinical practice.

Plasma Fibrinogen-Like 1 as a Potential Biomarker for Radiation-Induced Liver Injury

Liver damage upon exposure to ionizing radiation, whether accidental or because of therapy can contribute to liver dysfunction. Currently, radiation therapy is used for various cancers including hepatocellular carcinoma; however, the treatment dose is limited by poor liver tolerance to radiation. Furthermore, reliable biomarkers to predict liver damage and associated side-effects are unavailable. Here, we investigated fibrinogen-like 1 (FGL1)-expression in the liver and plasma after radiation exposure. We found that 30 Gy of liver irradiation (IR) induced cell death including apoptosis, necrosis, and autophagy, with fibrotic changes in the liver occurring during the acute and subacute phase in mice. Moreover, FGL1 expression pattern in the liver following IR was associated with liver damage represented by injury-related proteins and oxidative stress markers. We confirmed the association between FGL1 expression and hepatocellular injury by exposing human hepatocytes to radiation. To determine its suitability, as a potential biomarker for radiation-induced liver injury, we measured FGL1 in the liver tissue and the plasma of mice following total body irradiation (TBI) or liver IR. In TBI, FGL1 showed the highest elevation in the liver compared to other major internal organs including the heart, lung, kidney, and intestine. Notably, plasma FGL1 showed good correlation with radiation dose by liver IR. Our data revealed that FGL1 upregulation indicates hepatocellular injury in response to IR. These results suggest that plasma FGL1 may represent a potential biomarker for acute and subacute radiation exposure to the liver.

Relationships between expression of BCS1L, mitochondrial bioenergetics, and fatigue among patients with prostate cancer

Introduction: Cancer-related fatigue (CRF) is the most debilitating symptom with the greatest adverse side effect on quality of life. The etiology of this symptom is still not understood. The purpose of this study was to examine the relationship between mitochondrial gene expression, mitochondrial oxidative phosphorylation, electron transport chain complex activity, and fatigue in prostate cancer patients undergoing radiotherapy (XRT), compared to patients on active surveillance (AS).

Methods: The study used a matched case–control and repeated-measures research design. Fatigue was measured using the revised Piper Fatigue Scale from 52 patients with prostate cancer. Mitochondrial oxidative phosphorylation, electron-transport chain enzymatic activity, and BCS1L gene expression were determined using patients’ peripheral mononuclear cells. Data were collected at three time points and analyzed using repeated measures ANOVA.

Results: The fatigue score was significantly different over time between patients undergoing XRT and AS (P<0.05). Patients undergoing XRT experienced significantly increased fatigue at day 21 and day 42 of XRT (P<0.01). Downregulated mitochondrial gene (BC1, ubiquinol-cytochrome c reductase, synthesis-like, BCS1L, P<0.05) expression, decreased OXPHOS-complex III oxidation (P<0.05), and reduced activity of complex III were observed over time in patients with XRT. Moreover, increased fatigue was significantly associated with downregulated BCS1L and decreased complex III oxidation in patients undergoing XRT.

Conclusion: Our results suggest that BCS1L and complex III in mitochondrial mononuclear cells are potential biomarkers and feasible therapeutic targets for acute XRT-induced fatigue in this clinical population.

Metabolomic Studies of Tissue Injury in Nonhuman Primates Exposed to Gamma-Radiation

Exposure to ionizing radiation induces a complex cascade of systemic and tissue-specific responses that lead to functional impairment over time in the surviving population. However, due to the lack of predictive biomarkers of tissue injury, current methods for the management of survivors of radiation exposure episodes involve monitoring of individuals over time for the development of adverse clinical symptoms and death. Herein, we report on changes in metabolomic and lipidomic profiles in multiple tissues of nonhuman primates (NHPs) that were exposed to a single dose of 7.2 Gy whole-body ⁶⁰Co γ-radiation that either survived or succumbed to radiation toxicities over a 60-day period. This study involved the delineation of the radiation effects in the liver, kidney, jejunum, heart, lung, and spleen. We found robust metabolic changes in the kidney and liver and modest changes in other tissue types at the 60-day time point in a cohort of NHPs. Remarkably, we found significant elevation of long-chain acylcarnitines in animals that were exposed to radiation across multiple tissue types underscoring the role of this class of metabolites as a generic indicator of radiation-induced normal tissue injury. These studies underscore the utility of a metabolomics approach for delineating anticipatory biomarkers of exposure to ionizing radiation.

Cytokines expression levels from tissue, plasma or serum as promising clinical biomarkers in adenocarcinoma of the prostate: a systematic review of recent findings

Prostate cancer (PC) is a common cancer (excluding non-melanoma skin cancer) in men in many parts of the world, although incidence and mortality rates vary significantly by population. In current medical practice, prognostic markers for PC include the presenting serum prostate-specific antigen (PSA) level, tumour Gleason score (GS) and clinical tumour stage. However, existing pre-treatment factors cannot be used to predict acute radiotherapy (RT)-induced toxicity. Therefore, new protein biomarkers are required in RT oncology to improve decision-making, treatment and therapy monitoring for PC patients. The aim of this systematic review is to the update potential research to address the difference in cytokine expression and their association with RT-induced toxicity and clinical outcomes. Studies were collected after searching three electronic databases: PubMed, Medline, and Google Scholar. An additional search was carried out through cross-check on a bibliography of selected articles. After the selection process made by two of the authors, 19 articles met the inclusion criteria and were included in the systematic review. Results from previous studies identified elevated levels of cytokines have been reported in several types of cancers and have sometimes correlated with disease progression or prognosis. Elevated levels of cytokine were noticed after immediate exposure to RT and their association with RT-induced acute/late toxicity of PC patients. Moreover, above studies also identified overexpression of cytokines on tumour biopsies and correlation with shortening cancer-specific survival and biochemical recurrence. Thus, altered levels of cytokine might be predictive biomarkers for RT-induced and clinical outcomes of PC patients.

Optical Metabolic Imaging for Assessment of Radiation-Induced Injury to Rat Kidney and Mitigation by Lisinopril

The kidney is one of the most radiosensitive organs; it is the primary dose-limiting organ in radiotherapies for upper abdominal cancers. The role of mitochondrial redox state in the development and treatment of renal radiation injury, however, remains ill-defined. This study utilizes 3D optical cryo-imaging to quantify renal mitochondrial bioenergetics dysfunction after 13 Gy leg-out partial body irradiation (PBI). Furthermore, the mitigating effects of lisinopril (lisino), an anti-hypertensive angiotensin converting enzyme inhibitor, is assessed in renal radiation-induced injuries. Around day 150 post-irradiation, kidneys are harvested for cryo-imaging. The 3D images of the metabolic indices (NADH, nicotinamide adenine dinucleotide, and FAD, flavin adenine dinucleotide) are acquired, and the mitochondrial redox states of the irradiated and irradiated + lisino kidneys are quantified by calculating the volumetric mean redox ratio (NADH/FAD). PBI oxidized renal mitochondrial redox state by 78%. The kidneys from the irradiated + lisino rats showed mitigation of mitochondrial redox state by 93% compared to the PBI group. The study provides evidence for an altered bioenergetics and energy metabolism in the rat model of irradiation-induced kidney damage. In addition, the results suggest that lisinopril mitigates irradiation damage by attenuating the oxidation of mitochondria leading to increase redox ratio.

A Potential Biomarker for Predicting the Risk of Radiation-Induced Fibrosis in the Lung

Biomarkers could play an essential role during triage in the aftermath of a radiological event, where exposure to radiation will be heterogeneous and complicated by concurrent trauma. Used alongside biodosimetry, biomarkers can identify victims in need of treatment for acute radiation effects, and might also provide valuable information on later developing consequences that need to be addressed as part of a treatment strategy. Indeed, because the lung is particularly sensitive to radiation and resultant late effects not only affect quality of life, but can also lead to morbidity, the risk of developing downstream pulmonary complications in exposed individuals requires assessment. In this study, analyses of changes in pulmonary and circulating content of club cell secretory protein (CCSP) and surfactant protein D (SP-D), expressed by epithelial club cells and type II pneumocytes in the lung, respectively, were used to evaluate pulmonary epithelial damage in several lung injury models. Using a combined radiation exposure model, fibrosis-susceptible C57BL/6J (C57) and alveolitis-prone C3H/HeJ (C3H) mice received 5 Gy total-body irradiation plus 2.5-10 Gy whole-lung irradiation, and lung and plasma samples were collected throughout the course of the radiation response, at time points ranging from 24 h to 26 weeks postirradiation. Radiation significantly reduced bronchiole CCSP coverage in C57 mice at 26 weeks, a response that varied in extent among animals, but correlated with the severity of fibrosis in each animal. Interestingly, plasma CCSP content was elevated in C57 mice at multiple time points preceding and during the fibrotic period; this response that was not observed in C3H mice. Circulating CCSP/SP-D ratios, calculated as an index of lung integrity, were similarly increased throughout the time course in C57, but not C3H, mice. Furthermore, when the thoracic doses were reduced to subthreshold levels for fibrosis induction (2.5 or 7.5 Gy), although the CCSP/SP-D ratio in lung homogenates demonstrated dose-responsive changes, this was not reflected in the plasma ratios at acute and late time points. Importantly, plasma CCSP/SP-D ratios also were not significantly altered in C57 mice exposed to LPS, and only transiently decreased in influenza-exposed mice, demonstrating a level of specificity for radiation-induced lung injury. These results indicate that the CCSP/SP-D ratio, measured in plasma, is sensitive to individual variation in radiation sensitivity, correlates with fibrosis development, can be detected early after exposure and is specific to radiation-induced injury. This suggests that the CCSP/SP-D ratio may be useful as a biomarker of radiation-induced pulmonary fibrosis.

Developments in toxicogenomics: understanding and predicting compound-induced toxicity from gene expression data

The toxicogenomics field aims to understand and predict toxicity by using 'omics' data in order to study systems-level responses to compound treatments. In recent years there has been a rapid increase in publicly available toxicological and 'omics' data, particularly gene expression data, and a corresponding development of methods for its analysis. In this review, we summarize recent progress relating to the analysis of RNA-Seq and microarray data, review relevant databases, and highlight recent applications of toxicogenomics data for understanding and predicting compound toxicity. These include the analysis of differentially expressed genes and their enrichment, signature matching, methods based on interaction networks, and the analysis of co-expression networks. In the future, these state-of-the-art methods will likely be combined with new technologies, such as whole human body models, to produce a comprehensive systems-level understanding of toxicity that reduces the necessity of in vivo toxicity assessment in animal models.

Evaluation of Mediators Associated with the Inflammatory Response in Prostate Cancer Patients Undergoing Radiotherapy

A recent “hot topic” in prostate cancer radiotherapy is the observed association between acute/late rectal toxicity and the presence of abdominal surgery before radiotherapy. The exact mechanism is unclear. Our working hypothesis was that a previous surgery may influence plasma level of inflammatory molecules and this might result in enhanced radiosensitivity. We here present results on the feasibility of monitoring the expression of inflammatory molecules during radiotherapy. Plasma levels of a panel of soluble mediators associated with the inflammatory response were measured in prostate cancer patients undergoing radical radiotherapy. We measured 3 cytokines (IL-1b, IL-6, and TNF alpha), 2 chemokines (CCL2 and CXCL8), and the long pentraxin PTX3. 20 patients were enrolled in this feasibility evaluation. All patients were treated with IMRT at 78 Gy. 3/20 patients reported grade 2 acute rectal toxicity, while 4/20 were scored as grade 2 late toxicity. CCL2 was the most interesting marker showing significant increase during and after radiotherapy. CCL2 levels at radiotherapy end could be modelled using linear regression including basal CCL2, age, surgery, hypertension, and use of anticoagulants. The 4 patients with late toxicity had CCL2 values at radiotherapy end above the median value. This trial is registered with ISRCTN64979094.

Global Gene Expression Response in Mouse Models of DNA Repair Deficiency after Gamma Irradiation

In the event of an improvised nuclear device or "dirty bomb" in a highly populated area, potentially hundreds of thousands of people will require screening to ensure that exposed individuals receive appropriate treatment. For this reason, there is a need to develop tools for high-throughput radiation biodosimetry. Gene expression represents an emerging approach to biodosimetry and could potentially provide an estimate of both absorbed dose and individual radiation-induced injury. Since approximately 2-4% of humans are thought to be radiosensitive, and would suffer greater radiological injury at a given dose than members of the general population, it is of interest to explore the potential impact of such sensitivity on the biodosimetric gene expression signatures being developed. In this study, we used wild-type mice and genetically engineered mouse models deficient in two DNA repair pathways that can contribute to radiation sensitivity to estimate the maximum effect of differences in radiosensitivity. We compared gene expression in response to a roughly equitoxic (LD_50/30) dose of gamma rays in wild-type C57BL/6 (8 Gy) and DNA double-strand break repair-deficient Atm^-/- (4 Gy) and Prkdc^scid (3 Gy) mutants of C57BL/6. Overall, 780 genes were significantly differentially expressed in wild-type mice one day postirradiation, 232 in Atm^-/- and 269 in Prkdc^scid. Upstream regulators including TP53 and NFκB were predicted to be activated by radiation exposure in the wild-type mice, but not in either of the DNA repair-deficient mutant strains. There was also a significant muting of the apparent inflammatory response triggered by radiation in both mutant strains. These differences impacted the ability of gene expression signatures developed in wild-type mice to detect potentially fatal radiation exposure in the DNA repair-deficient mice, with the greatest impact on Atm^-/- mice. However, the inclusion of mutant mice in gene selection vastly improved performance of the classifiers.

Validation of the Gatortail method for accurate sizing of pulmonary vessels from 3D medical images

PURPOSE

Detailed characterization of changes in vessel size is crucial for the diagnosis and management of a variety of vascular diseases. Because clinical measurement of vessel size is typically dependent on the radiologist's subjective interpretation of the vessel borders, it is often prone to high inter- and intra-user variability. Automatic methods of vessel sizing have been developed for two-dimensional images but a fully three-dimensional (3D) method suitable for vessel sizing from volumetric X-ray computed tomography (CT) or magnetic resonance imaging has heretofore not been demonstrated and validated robustly.

METHODS

In this paper, we refined and objectively validated Gatortail, a method that creates a mathematical geometric 3D model of each branch in a vascular tree, simulates the appearance of the virtual vascular tree in a 3D CT image, and uses the similarity of the simulated image to a patient's CT scan to drive the optimization of the model parameters, including vessel size, to match that of the patient. The method was validated with a 2-dimensional virtual tree structure under deformation, and with a realistic 3D-printed vascular phantom in which the diameter of 64 branches were manually measured 3 times each. The phantom was then scanned on a conventional clinical CT imaging system and the images processed with the in-house software to automatically segment and mathematically model the vascular tree, label each branch, and perform the Gatortail optimization of branch size and trajectory. Previously proposed methods of vessel sizing using matched Gaussian filters and tubularity metrics were also tested. The Gatortail method was then demonstrated on the pulmonary arterial tree segmented from a human volunteer's CT scan.

RESULTS

The standard deviation of the difference between the manually measured and Gatortail-based radii in the 3D physical phantom was 0.074 mm (0.087 in-plane pixel units for image voxels of dimension 0.85 × 0.85 × 1.0 mm) over the 64 branches, representing vessel diameters ranging from 1.2 to 7 mm. The linear regression fit gave a slope of 1.056 and an R² value of 0.989. These three metrics reflect superior agreement of the radii estimates relative to previously published results over all sizes tested. Sizing via matched Gaussian filters resulted in size underestimates of >33% over all three test vessels, while the tubularity-metric matching exhibited a sizing uncertainty of >50%. In the human chest CT data set, the vessel voxel intensity profiles with and without branch model optimization showed excellent agreement and improvement in the objective measure of image similarity.

CONCLUSIONS

Gatortail has been demonstrated to be an automated, objective, accurate and robust method for sizing of vessels in 3D non-invasively from chest CT scans. We anticipate that Gatortail, an image-based approach to automatically compute estimates of blood vessel radii and trajectories from 3D medical images, will facilitate future quantitative evaluation of vascular response to disease and environmental insult and improve understanding of the biological mechanisms underlying vascular disease processes.

Simvastatin ameliorates ionizing radiation-induced apoptosis in the thymus by activating the AKT/sirtuin 1 pathway in mice

Simvastatin is a HMG-CoA reductase inhibitor widely used to lower plasma cholesterol and to protect against cardiovascular risk factors. The aim of this study was to investigate whether simvastatin attenuates ionizing radiation-induced damage in the mouse thymus and to elucidate the possible mechanisms invovled. For this purpose, male C57BL/6J mice aged 6 weeks were used and exposed to 4 Gy ⁶⁰Co γ-radiation with or without simvastatin (20 mg/kg/day, for 14 days). Apoptosis was determined by terminal deoxynucle-otidyltransferase-mediated dUTP nick-end labeling (TUNEL) assay or transmission electron microscopy (TEM) examination. Thymocytes were also isolated and incubated in DMEM supplemented with 10% FBS at 37°C and exposed to 8 Gy ⁶⁰Co γ-radiation with or without simvastatin (20 µM). The expression levels of Bcl-2, p53, p-p53, AKT, sirtuin 1 and poly(ADP-ribose) polymerase (PARP) were determined by western blot analysis. TUNEL and TEM examination revealed that simvastatin treatment significantly mitigated ionizing radiation-induced apoptosis in the mouse thymus. It was also found that simvastatin treatment increased AKT/sirtuin 1 expression following exposure to ionizing radiation in vivo and in vitro. In the in vivo model, but not in the in vitro model, Bcl-2 and PARP expression was augmented and that of p53/p-p53 decreased following treatment with simvastatin. On the whole, our findings indicate that simvastatin exerts a protective effect against ionizing radiation-induced damage in the mouse thymus, which may be partially attributed to the activation of the AKT/sirtuin 1 pathway.

Tissue TGF-β expression following conventional radiotherapy and pulsed low-dose-rate radiation

The release of inflammatory cytokines has been implicated in the toxicity of conventional radiotherapy (CRT). Transforming growth factor β (TGF-β) has been suggested to be a risk marker for pulmonary toxicity following radiotherapy. Pulsed low-dose rate radiotherapy (PLDR) is a technique that involves spreading out a conventional radiotherapy dose into short pulses of dose with breaks in between to reduce toxicities. We hypothesized that the more tolerable toxicity profile of PLDR compared with CRT may be related to differential expression of inflammatory cytokines such as TGF-β in normal tissues. To address this, we analyzed tissues from mice that had been subjected to lethal doses of CRT and PLDR by histology and immunohistochemistry (IHC). Equivalent physical doses of CRT triggered more cellular atrophy in the bone marrow, intestine, and pancreas when compared with PLDR as indicated by hematoxylin and eosin staining. IHC data indicates that TGF-β expression is increased in the bone marrow, intestine, and lungs of mice subjected to CRT as compared with tissues from mice subjected to PLDR. Our in vivo data suggest that differential expression of inflammatory cytokines such as TGF-β may play a role in the more favorable normal tissue late response following treatment with PLDR.

MODELING H-ARS USING HEMATOLOGICAL PARAMETERS: A COMPARISON BETWEEN THE NON-HUMAN PRIMATE AND MINIPIG

Multiple hematological biomarkers (i.e. complete blood counts and serum chemistry parameters) were used in a multivariate linear-regression fit to create predictive algorithms for estimating the severity of hematopoietic acute radiation syndrome (H-ARS) using two different species (i.e. Göttingen Minipig and non-human primate (NHP) (Macacca mulatta)). Biomarker data were analyzed prior to irradiation and between 1-60 days (minipig) and 1-30 days (NHP) after irradiation exposures of 1.6-3.5 Gy (minipig) and 6.5 Gy (NHP) ⁶⁰Co gamma ray doses at 0.5-0.6 Gy min^-1 and 0.4 Gy min^-1, respectively. Fitted radiation risk and injury categorization (RRIC) values and RRIC prediction percent accuracies were compared between the two models. Both models estimated H-ARS severity with over 80% overall predictive power and with receiver operating characteristic curve area values of 0.884 and 0.825. These results based on two animal radiation models support the concept for the use of a hematopoietic-based algorithm for predicting the risk of H-ARS in humans.

Acute Radiation Syndrome Severity Score System in Mouse Total-Body Irradiation Model

Radiation accidents or terrorist attacks can result in serious consequences for the civilian population and for military personnel responding to such emergencies. The early medical management situation requires quantitative indications for early initiation of cytokine therapy in individuals exposed to life-threatening radiation doses and effective triage tools for first responders in mass-casualty radiological incidents. Previously established animal (Mus musculus, Macaca mulatta) total-body irradiation (γ-exposure) models have evaluated a panel of radiation-responsive proteins that, together with peripheral blood cell counts, create a multiparametic dose-predictive algorithm with a threshold for detection of ~1 Gy from 1 to 7 d after exposure as well as demonstrate the acute radiation syndrome severity score systems created similar to the Medical Treatment Protocols for Radiation Accident Victims developed by Fliedner and colleagues. The authors present a further demonstration of the acute radiation sickness severity score system in a mouse (CD2F1, males) TBI model (1-14 Gy, Co γ-rays at 0.6 Gy min) based on multiple biodosimetric endpoints. This includes the acute radiation sickness severity Observational Grading System, survival rate, weight changes, temperature, peripheral blood cell counts and radiation-responsive protein expression profile: Flt-3 ligand, interleukin 6, granulocyte-colony stimulating factor, thrombopoietin, erythropoietin, and serum amyloid A. Results show that use of the multiple-parameter severity score system facilitates identification of animals requiring enhanced monitoring after irradiation and that proteomics are a complementary approach to conventional biodosimetry for early assessment of radiation exposure, enhancing accuracy and discrimination index for acute radiation sickness response categories and early prediction of outcome.

Big Data and machine learning in radiation oncology: State of the art and future prospects

Precision medicine relies on an increasing amount of heterogeneous data. Advances in radiation oncology, through the use of CT Scan, dosimetry and imaging performed before each fraction, have generated a considerable flow of data that needs to be integrated. In the same time, Electronic Health Records now provide phenotypic profiles of large cohorts of patients that could be correlated to this information. In this review, we describe methods that could be used to create integrative predictive models in radiation oncology. Potential uses of machine learning methods such as support vector machine, artificial neural networks, and deep learning are also discussed.

Concepts of Operations (CONOPS) for Biodosimetry Tools Employed in Operational Environments

It is essential to identify improved capabilities to accurately identify, confirm, and/or quantify radiological exposure and injury in order to inform critical triage, diagnosis, and treatment decisions. Herein the authors report characteristic requirements and potential Concepts of Operations (CONOPS) for biodosimetry tools employed in operational environments. While similar significant efforts have been completed in this area for the U.S. civilian sector, limited perspectives are published in the peer-reviewed literature regarding the use of radiological diagnostic technologies in deployed military medical treatment settings. Two radiological exposure scenarios were developed to clarify the diagnostic performance criteria and identify capability gaps. The emerging technology areas associated with radiation exposure diagnostics were reviewed and assessed to gauge their suitability in supporting triage, treatment, and return to duty decisions within the military medical support system.

Necrostatin-1 rescues mice from lethal irradiation

There is an emerging need in new medical products that can mitigate and/or treat the short- and long-term consequences of radiation exposure after a radiological or nuclear terroristic event. The direct effects of ionizing radiation are realized primarily via apoptotic death pathways in rapidly proliferating cells within the initial 1-2days after the exposure. However later in the course of the radiation disease necrotic cell death may ensue via direct and indirect pathways from increased generation of pro-inflammatory cytokines. Here we evaluated radiomitigative potential of necrostatin-1 after total body irradiation (TBI) and the contribution of necroptosis to cell death induced by radiation. Circulating TNFα levels were increased starting on d1 after TBI and associated with increased plasmalemma permeability in ileum of irradiated mice. Necrostatin-1 given iv. 48h after 9.5Gy TBI attenuated radiation-induced receptor interacting protein kinase 3 (RIPK3) serine phosphorylation in ileum and improved survival vs. vehicle. Utilizing apoptosis resistant cytochrome c(-/-) cells, we showed that radiation can induce necroptosis, which is attenuated by RNAi knock down of RIPK1 and RIPK3 or by treatment with necrostatin-1 or -1s whereas 1-methyl-L-tryptophan, an indoleamine-2,3-dioxygenase inhibitor, did not exhibit radiomitigative effect. This suggests that the beneficial effect of necrostatin-1 is likely through inhibition of RIPK1-mediated necroptotic pathway. Overall, our data indicate that necroptosis, a form of programmed necrosis, may play a significant role in cell death contributing to radiation disease and mortality. This study provides a proof of principle that necrostatin-1 and perhaps other RIPK1 inhibitors are promising therapeutic agents for radiomitigation after TBI.

Triptolide Mitigates Radiation-Induced Pulmonary Fibrosis

Triptolide (TPL) may mitigate radiation-induced late pulmonary side effects through its inhibition of global pro-inflammatory cytokines. In this study, we evaluated the effect of TPL in C57BL/6 mice, the animals were exposed to radiation with vehicle (15 Gy), radiation with TPL (0.25 mg/kg i.v., twice weekly for 1, 2 and 3 months), radiation and celecoxib (CLX) (30 mg/kg) and sham irradiation. Cultured supernatant of irradiated RAW 264.7 and MLE-15 cells and lung lysate in different groups were enzyme-linked immunosorbent assays at 33 h. Respiratory rate, pulmonary compliance and pulmonary density were measured at 5 months in all groups. The groups exposed to radiation with vehicle and radiation with TPL exhibited significant differences in respiratory rate and pulmonary compliance (480 ± 75/min vs. 378 ± 76/min; 0.6 ± 0.1 ml/cm H2O/p kg vs. 0.9 ± 0.2 ml/cm H2O/p kg). Seventeen cytokines were significantly reduced in the lung lysate of the radiation exposure with TPL group at 5 months compared to that of the radiation with vehicle group, including profibrotic cytokines implicated in pulmonary fibrosis, such as IL-1β, TGF- β1 and IL-13. The radiation exposure with TPL mice exhibited a 41% reduction of pulmonary density and a 25% reduction of hydroxyproline in the lung, compared to that of radiation with vehicle mice. The trichrome-stained area of fibrotic foci and pathological scaling in sections of the mice treated with radiation and TPL mice were significantly less than those of the radiation with vehicle-treated group. In addition, the radiation with TPL-treated mice exhibited a trend of improved survival rate compared to that of the radiation with vehicle-treated mice at 5 months (83% vs. 53%). Three radiation-induced profibrotic cytokines in the radiation with vehicle-treated group were significantly reduced by TPL treatment, and this partly contributed to the trend of improved survival rate and pulmonary density and function and the decreased severity of pulmonary fibrosis at 5 months. Our findings indicate that TPL could be a potential new agent to mitigate radiation-induced pulmonary fibrosis.

Serum Amyloid A as a Biomarker for Radiation Exposure

There is a need for minimally invasive biomarkers that can accurately and quickly quantify radiation exposure. Radiation-responsive proteins have applications in clinical medicine and for mass population screenings after a nuclear or radiological incident where the level of radiation exposure and exposure pattern complicate medical triage for first responders. In this study, we evaluated the efficacy of the acute phase protein serum amyloid A (SAA) as a biomarker for radiation exposure using plasma from irradiated mice. Ten-week-old female C57BL6 mice received a 1-8 Gy single whole-body or partial-body dose from a Pantak X-ray source at a dose rate of 2.28 Gy/min. Plasma was collected by mandibular or cardiac puncture at 6, 24, 48 and 72 h or 1-3 weeks postirradiation. SAA levels were determined using a commercially available ELISA assay. Data was pooled to generate SAA μg/ml threshold values correlating plasma SAA levels with radiation dose. SAA levels were statistically significant over control at all exposures between 2 and 8 Gy at 24 h postirradiation but not at 6, 48 and 72 h or 1-3 weeks postirradiation. SAA levels at 1 Gy were not significantly elevated over control at all time points. Total-body-irradiated (TBI) SAA levels at 24 h were used to generate a dose prediction model that successfully differentiated TBI mice into dose received cohorts of control/1 Gy and ≥ 2 Gy groups with a high degree of accuracy in a blind study. Dose prediction of partial-body exposures based on the TBI model correlated increasing predictive accuracy with percentage of body exposure to radiation. Our findings indicate that plasma SAA levels might be a useful biomarker for radiation exposure in a variety of total- and partial-body irradiation settings.

Correlations Between Serum IL-6 Levels and Radiation Pneumonitis in Lung Cancer Patients: A Meta-Analysis

OBJECTIVE

Diagnostic significance of interleukin 6 (IL-6) for lung cancer patients with radiation pneumonitis (RP) was examined within various studies, but yielded conflicting results. Thus, this meta-analysis was performed to demonstrate correlations between serum IL-6 levels and RP in lung cancer patients.

METHOD

Electronic databases updated to March 2014 were searched to find relevant studies. Relevant literatures were searched under the PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, CBM and CNKI databases. STATA statistical software (Version 12.0, Stata Corporation, and College Station, TX) Standardized mean difference (SMD), and its corresponding 95% confidence intervals (CIs) were used for this meta-analysis. In addition, nine cohort studies met the inclusion criteria and involved a total of 137 RP patients and 295 non-RP patients.

RESULTS

The results of combined SMD suggested that serum IL-6 levels in RP patients was significantly higher than in non-RP patients before radiotherapy. While, there was a significant difference in serum IL-6 levels of RP patients between before and after radiotherapy, we observed no difference in serum IL-6 levels between RP patients and non-RP patients after radiotherapy. Ethnicity-stratified analyses indicated that increased serum IL-6 levels were related to the risk of RP in lung cancer patients among Caucasians, but not detected among Asians (all P > 0.05).

CONCLUSION

The main finding of our meta-analysis reveals that increased serum IL-6 levels may contribute to the incidence of RP in lung cancer patients, especially among Caucasians.

Vision 20/20: the role of Raman spectroscopy in early stage cancer detection and feasibility for application in radiation therapy response assessment

Raman spectroscopy is an optical technique capable of identifying chemical constituents of a sample by their unique set of molecular vibrations. Research on the applicability of Raman spectroscopy in the differentiation of cancerous versus normal tissues has been ongoing for many years, and has yielded successful results in the context of prostate, breast, brain, skin, and head and neck cancers as well as pediatric tumors. Recently, much effort has been invested on developing noninvasive "Raman" probes to provide real-time diagnosis of potentially cancerous tumors. In this regard, it is feasible that the Raman technique might one day be used to provide rapid, minimally invasive real-time diagnosis of tumors in patients. Raman spectroscopy is relatively new to the field of radiation therapy. Recent work involving cell lines has shown that the Raman technique is able to identify proteins and other markers affected by radiation therapy. Although this work is preliminary, one could ask whether or not the Raman technique might be used to identify molecular markers that predict radiation response. This paper provides a brief review of Raman spectroscopic investigations in cancer detection, benefits and limitations of this method, advances in instrument development, and also preliminary studies related to the application of this technology in radiation therapy response assessment.

Long-term differential changes in mouse intestinal metabolomics after γ and heavy ion radiation exposure

Tissue consequences of radiation exposure are dependent on radiation quality and high linear energy transfer (high-LET) radiation, such as heavy ions in space is known to deposit higher energy in tissues and cause greater damage than low-LET γ radiation. While radiation exposure has been linked to intestinal pathologies, there are very few studies on long-term effects of radiation, fewer involved a therapeutically relevant γ radiation dose, and none explored persistent tissue metabolomic alterations after heavy ion space radiation exposure. Using a metabolomics approach, we report long-term metabolomic markers of radiation injury and perturbation of signaling pathways linked to metabolic alterations in mice after heavy ion or γ radiation exposure. Intestinal tissues (C57BL/6J, female, 6 to 8 wks) were analyzed using ultra performance liquid chromatography coupled with electrospray quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS) two months after 2 Gy γ radiation and results were compared to an equitoxic ⁵⁶Fe (1.6 Gy) radiation dose. The biological relevance of the metabolites was determined using Ingenuity Pathway Analysis, immunoblots, and immunohistochemistry. Metabolic profile analysis showed radiation-type-dependent spatial separation of the groups. Decreased adenine and guanosine and increased inosine and uridine suggested perturbed nucleotide metabolism. While both the radiation types affected amino acid metabolism, the ⁵⁶Fe radiation preferentially altered dipeptide metabolism. Furthermore, ⁵⁶Fe radiation caused upregulation of ‘prostanoid biosynthesis’ and ‘eicosanoid signaling’, which are interlinked events related to cellular inflammation and have implications for nutrient absorption and inflammatory bowel disease during space missions and after radiotherapy. In conclusion, our data showed for the first time that metabolomics can not only be used to distinguish between heavy ion and γ radiation exposures, but also as a radiation-risk assessment tool for intestinal pathologies through identification of biomarkers persisting long after exposure.

Repeated delayed onset cerebellar radiation injuries after linear accelerator-based stereotactic radiosurgery for vestibular schwannoma: case report

A 63-year-old woman presented with right hearing disturbance and vertigo. Magnetic resonance (MR) imaging revealed the presence of right vestibular schwannoma (VS). Stereotactic radiosurgery (SRS) was performed with a tumor marginal dose of 14 Gy using two isocenters. She was followed up clinically and neuroradiologically using three-dimensional spoiled gradient-echo MR imaging. She experienced temporal neurological deterioration due to peritumoral edema in her right cerebellar peduncle and pons for a few months beginning 1.5 years after SRS, when she experienced transient right facial dysesthesia and hearing deterioration. Ten years after SRS, the patient presented with sudden onset of vertigo, gait disturbance, diplopia, dysarthria, and nausea. MR imaging demonstrated a new lesion in the right cerebellar peduncle, which was diagnosed as radiation-induced stroke. The patient was followed up conservatively and her symptoms disappeared within a few months. Multiple delayed onset radiation injuries are possible sequelae of SRS for VS.

Role of interleukin-1β in radiation-enhancement of MDA-MB-231 breast cancer cell invasion

The ability of radiation to increase the invasiveness of cancer cells is associated with the inflammatory response, which is induced in almost all irradiated patients. For breast cancer patients, elevated plasma levels of the inflammatory cytokine interleukin-1β (IL1β) persisted for a few weeks after completion of radiotherapy. The aim of this study was to determine whether IL1β is involved in the enhancement of breast cancer cell invasion induced by radiation. The role of IL1β was assessed with invasion chambers where irradiated fibroblasts were used as chemoattractant for the MDA-MB-231 breast cancer cells plated in the upper compartment. The ability of IL1β to stimulate the expression of cyclooxygenase-2 (COX-2) and biosynthesis of the prostaglandin E2 (PGE2) in MDA-MB-231 cells were also determined. Our results show that radiation-enhancement of MDA-MB-231 cell invasion was prevented with an anti-IL1β antibody. The production of IL1β was increased in irradiated fibroblasts, while the invasiveness of the MDA-MB-231 cells not exposed to irradiated fibroblasts was favored by adding this cytokine. Furthermore, addition of the COX-2 inhibitor NS-398 prevented the stimulation of cancer cell invasion induced either by irradiated fibroblasts or IL1β. We propose that the effect of IL1β on the invasiveness of the MDA-MB-231 cells involves elevation of matrix metalloproteinase-9 (MMP-9) production, induction of COX-2 expression and PGE2 biosynthesis. In conclusion, this study supports the involvement of IL1β in the radiation-enhancement of breast cancer cell invasion.

Biomarkers for anti-angiogenic therapy in cancer

Angiogenesis, the development of new vessels from existing vasculature, plays a central role in tumor growth, survival, and progression. On the molecular level it is controlled by a number of pro- and anti-angiogenic cytokines, among which the vascular endothelial growth factors (VEGFs), together with their related VEGF-receptors, have an exceptional position. Therefore, the blockade of VEGF signaling in order to inhibit angiogenesis was deemed an attractive approach for cancer therapy and drugs interfering with the VEGF-ligands, the VEGF receptors, and the intracellular VEGF-mediated signal transduction were developed. Although promising in pre-clinical trials, VEGF-inhibition proved to be problematic in the clinical context. One major drawback was the generally high variability in patient response to anti-angiogenic drugs and the rapid development of therapy resistance, so that, in total, only moderate effects on progression-free and overall survival were observed. Biomarkers predicting the response to VEGF-inhibition might attenuate this problem and help to further individualize drug and dosage determination. Although up to now no definitive biomarker has been identified for this purpose, several candidates are currently under investigation. This review aims to give an overview of the recent developments in this field, focusing on the most prevalent tumor species.

Cytokines associated with toxicity in the treatment of recurrent glioblastoma with aflibercept

Plasma profiling of patients treated with antiangiogenic agents may identify markers that correlate with toxicity. Objectives were to correlate changes in cytokine and angiogenic factors as potential markers of toxicity to aflibercept. Circulating cytokine and angiogenic factors were measured in 28 patients with recurrent glioblastoma in a single-arm phase II study of aflibercept. Plasma samples were analyzed at baseline, 24 h, and 28 days using multiplex assays or ELISA. We evaluated log-transformed baseline biomarker expressions with Cox proportional hazard regression models to assess the effect of markers on any grade II-IV (Gr II-IV) toxicity, on-target toxicity (hypertension, proteinuria, thromboembolism), and fatigue. All tests were two sided with a statistical significance level of p = 0.05. Among 28 pts, there were 116 Gr II-IV events. Changes in IL-13 from baseline to 24 h predicted on-target toxicities. Increases in IL-1b, IL-6, and IL-10 at 24 h were significantly associated with fatigue. Progression-free survival was 14.9 months for patients in the all-toxicity group and 9.0 months for patients in the on-target toxicity group compared to 4.3 months for those who did not develop any Gr II-IV toxicity (p = 0.002 and p = 0.045, respectively). Toxicity from antiangiogenic therapy remains an important cause of antiangiogenic treatment discontinuation and patient morbidity. Changes in IL6, IL10, and IL13 were repeatedly correlated with toxicity. Profiling of IL-13 as a surrogate for endothelial dysfunction could individualize patients at risk during antiangiogenic therapy, as could identifying those at higher risk for fatigue using IL-6 and IL-10.

Genomic determinants of normal tissue toxicity after radiotherapy for head and neck malignancy: a systematic review

Interindividual variations in radiotoxicity responses exist despite uniform treatment protocols. It is speculated that normal genetic variants, particularly single nucleotide polymorphisms (SNPs) may influence normal head and neck (HN) tissue radiotoxicity. This first-ever systematic review was undertaken to evaluate the association of SNPs with normal HN tissues radiotoxicity. Multiple databases (1950-February 2012) were reviewed using a combination of related keywords and MeSH terms. All published HN radiotoxicity studies with sufficient relevant data for extraction were included. The outcomes evaluated were acute and late radiotoxicity endpoints. Methodological quality assessment based on the STrengthening the REporting of Genetic Association (STREGA) statement was performed. Seven articles from 692 articles searched fulfilled the eligibility criteria. Recruited sample sizes were small (range, 32-140). There were 5/7 case-control studies. All studies used multimodality treatment with heterogeneous radiation parameters. Candidate gene approach was used in all studies. Fourteen SNPs from 9 genes were evaluated from the following pathways: DNA damage response, radiation fibrogenesis and oxidative/xenobiotic metabolism. Acute radiotoxicity events were associated with SNPs of DNA repair genes (OR, 3.01-4.08). SNPs of TGFβ1 were associated with osteoradionecrosis (OR, 4.2) and subcutaneous fibrosis. Genetic association studies in HN radiotoxicity currently provide hypothesis-generating findings that require validation in larger studies. Future studies must incorporate critical methodological issues and technological improvements, including using a genome-wide approach. Headway is possible through case-pooling of existing clinical trial data which could create a larger sample size of well-characterized treatment and endpoints. Also, on-going HN cancer clinical trials should consider extending their toxicity evaluation to include genetic association studies.

Strategies to optimize radiotherapy based on biological responses of tumor and normal tissue

Rapid developments in radiation oncology are currently taking place. Radiation-induced responses are being increasingly used for radiotherapy modification based on advancements in radiobiology. In the process of radiation treatment, radiobiological responses of tumor and normal tissue in patients are monitored non-invasively by a variety of techniques including imaging, biological methods and biochemical assays. Information collected using these methods and data on responses are further incorporated into radiotherapy optimization approaches, which not only include the optimization of radiation treatment planning, such as dose distributions in targets and treatment delivery, but also include radiation sensitivity modification and gene radiotherapy of the tumor and normal tissue. Hence, the highest tumor control rate is obtained with the utmost protection being afforded to normal tissue under this treatment modality.

Swallowing dysfunction in head and neck cancer patients treated by radiotherapy: review and recommendations of the supportive task group of the Italian Association of Radiation Oncology

PURPOSE

Dysphagia is a debilitating complication in head and neck cancer patients (HNCPs) that may cause a high mortality rate for aspiration pneumonia. The aims of this paper were to summarize the normal swallowing mechanism focusing on its anatomo-physiology, to review the relevant literature in order to identify the main causes of dysphagia in HNCPs and to develop recommendations to be adopted for radiation oncology patients. The chemotherapy and surgery considerations on this topic were reported in recommendations only when they were supposed to increase the adverse effects of radiotherapy on dysphagia.

MATERIALS AND METHODS

The review of literature was focused on studies reporting dysphagia as a pre-treatment evaluation and as cancer and cancer therapy related side-effects, respectively. Relevant literature through the primary literature search and by articles identified in references was considered. The members of the group discussed the results and elaborated recommendations according to the Oxford CRBM levels of evidence and recommendations. The recommendations were revised by external Radiation Oncology, Ear Nose and Throat (ENT), Medical Oncology and Speech Language Pathology (SLP) experts.

RESULTS

Recommendations on pre-treatment assessment and on patients submitted to radiotherapy were given. The effects of concurrent therapies (i.e. surgery or chemotherapy) were taken into account.

CONCLUSIONS

In HNCPs treatment, disease control has to be considered in tandem with functional impact on swallowing function. SLPs should be included in a multidisciplinary approach to head and neck cancer.

Interaction between total body gamma-irradiation and choline deficiency triggers immediate modulation of choline and choline-containing moieties

PURPOSE

The objective of this study was to examine the effect of 60Co-gamma (γ) radiation on acute phase modulation, if any, of choline and choline-containing moieties in choline-deficient subjects. Corresponding results could provide information that might be useful in the management of adverse effects of γ-radiation.

MATERIALS AND METHODS

Male Swiss mice maintained on a choline-sufficient diet (CSD) and choline-free diet (CFD) based on AIN-93M formula, were subjected to whole body γ-irradiation (2-6 Gy). Liver, serum and brain samples from each group were then tested for: (i) Alterations in choline and choline-containing moieties such as phosphatidylcholine (PC) and sphingomyeline (SM); and (ii) modulation of choline profile modulating enzymes such as phospholipase D (PLD) and total sphingomyelinase (t-SMase). Liver and brain samples were also subjected to histo-pathological examinations.

RESULTS

No significant changes were observed in folate, choline, choline-containing moieties and choline-modulating enzymes in choline-sufficient mice. In contrast, interaction between cytotoxic effects of γ-radiation and choline deficiency modulated choline and choline-containing moieties. Feeding CFD reduced hepatic concentrations of choline, PC and SM whereas PLD and t-SMase activities were significantly raised. The decrease in liver choline and choline-containing moieties was accompanied by an increase in blood choline concentration. Despite choline deficiency, the level of choline and acetylcholine synthesizing enzyme choline acetyltransfease (ChAT) significantly increased in the brain.

CONCLUSIONS

We propose that choline deprivation and γ-radiation interact to modulate choline reserves of hepatic tissue, which might release choline to blood. Our studies also clearly showed that interaction between choline deficiency and γ-radiation might substantially enhance liver adipogenesis.

Prevention of future incidents and investigational lines

All radiation devices in use nowadays are subject to cause serious incidents and accidents, with potential risks in exposed population groups. These risks may have immediate or long term health implications. The detection of radioactive incidents is a procedure that should be systematized in economically developed societies. International organizations may provide support to other states in the event of a radioactive incident. Prevention, mitigation and treatment of the radiation effects are done by anticipating the moment of exposure and by establishing new efforts for investigation of radioprotective products. In this article we will analyze the causes of radiological incidents, the means to detect them, and the current preventive and therapeutic procedures available, with special emphasis on new biodosimetry methods for triage and investigational radioprotective drugs. Finally, we will explore the most efficient measures, for future prevention.