A pathological convergence theory for non-communicable diseases

The current paradigm considers the study of non-communicable diseases (NCDs), which are the main causes of mortality, as individual disorders. Nevertheless, this conception is being solidly challenged by numerous remarkable studies. The clear fact that the mortality, by virtually all NCDs, tends to cluster at old ages (with the exception of congenital malformations and certain types of cancer, among a few others); makes us intuitive to assume that the common convergence mechanism that exponentially increases mortality by almost all NCDs in older ages is cell aging. Moreover, when we study NCDs, we are not analyzing which disorders cause the mortality of the populations, rather that which disorders kill us before others do, because the aging of the individuals causes inevitably their death by one cause or another. This is not a defeatist perspective, but a challenging and efficient one. These intuitive assumptions have been supported by studies from the pathophysiologic, epidemiologic, and genetic fields, leading to the affirmation that, as NCDs share genetic and pathophysiological mechanisms (derived from mostly the same risk factors), they should no longer be considered independently. Those studies should make us reconsider our current conceptions of studying NCDs as individual disorders, and to hypothesize about a paradigm that would consider most NCDs (cancer, neurological pathologies, cardiovascular diseases, type II diabetes mellitus, chronic respiratory diseases, osteoarthritis, and osteoporosis, among others) different manifestations of the same process: the cell aging.

Postsynaptic density radiation signature following space irradiation

Introduction: The response of the brain to space radiation is an important concern for astronauts during space missions. Therefore, we assessed the response of the brain to ²⁸Si ion irradiation (600 MeV/n), a heavy ion present in the space environment, on cognitive performance and whether the response is associated with altered DNA methylation in the hippocampus, a brain area important for cognitive performance. Methods: We determined the effects of ²⁸Si ion irradiation on object recognition, 6-month-old mice irradiated with ²⁸Si ions (600 MeV/n, 0.3, 0.6, and 0.9 Gy) and cognitively tested two weeks later. In addition, we determined if those effects were associated with alterations in hippocampal networks and/or hippocampal DNA methylation. Results: At 0.3 Gy, but not at 0.6 Gy or 0.9 Gy, ²⁸Si ion irradiation impaired cognition that correlated with altered gene expression and 5 hmC profiles that mapped to specific gene ontology pathways. Comparing hippocampal DNA hydroxymethylation following proton, ⁵⁶Fe ion, and ²⁸Si ion irradiation revealed a general space radiation synaptic signature with 45 genes that are associated with profound phenotypes. The most significant categories were glutamatergic synapse and postsynaptic density. Discussion: The brain's response to space irradiation involves novel excitatory synapse and postsynaptic remodeling.

miR-484: A Potential Biomarker in Health and Disease

Disorders of miR-484 expression are observed in cancer, different diseases or pathological states. There is accumulating evidence that miR-484 plays an essential role in the development as well as the regression of different diseases, and miR-484 has been reported as a key regulator of common cancer and non-cancer diseases. The miR-484 targets that have effects on inflammation, apoptosis and mitochondrial function include SMAD7, Fis1, YAP1 and BCL2L13. For cancer, identified targets include VEGFB, VEGFR2, MAP2, MMP14, HNF1A, TUSC5 and KLF12. The effects of miR-484 on these targets have been documented separately. Moreover, miR-484 is typically described as an oncosuppressor, but this claim is simplistic and one-sided. This review will combine relevant basic and clinical studies to find that miR-484 promotes tumorigenesis and metastasis in liver, prostate and lung tissues. It will provide a basis for the possible mechanisms of miR-484 in early tumor diagnosis, prognosis determination, disease assessment, and as a potential therapeutic target for tumors.

Early molecular markers for retrospective biodosimetry and prediction of acute health effects

Radiation-induced biological changes occurring within hours and days after irradiation can be potentially used for either exposure reconstruction (retrospective dosimetry) or the prediction of consecutively occurring acute or chronic health effects. The advantage of molecular protein or gene expression (GE) (mRNA) marker lies in their capability for early (1-3 days after irradiation), high-throughput and point-of-care diagnosis, required for the prediction of the acute radiation syndrome (ARS) in radiological or nuclear scenarios. These molecular marker in most cases respond differently regarding exposure characteristics such as e.g. radiation quality, dose, dose rate and most importantly over time. Changes over time are in particular challenging and demand certain strategies to deal with. With this review, we provide an overview and will focus on already identified and used mRNA GE and protein markers of the peripheral blood related to the ARS. These molecules are examined in light of 'ideal' characteristics of a biomarkers (e.g. easy accessible, early response, signal persistency) and the validation degree. Finally, we present strategies on the use of these markers considering challenges as their variation over time and future developments regarding e.g. origin of samples, point of care and high-throughput diagnosis.

Detection of Embedded Low-level Radioactive Shrapnel after the Explosion of a Radiological Dispersal Device in Radiological Emergency Imaging

Concern about the threat of a terrorist attack with a Radiological Dispersal Device has increased considerably over the last few years, and this comes along with an immense challenge, especially regarding medical treatment of combined injuries with incorporated radioactive fragments. In such scenarios, the identification and surgical exploration of radioactive fragments is a major issue to prevent further radiation-induced effects like wound healing disorders, onset of acute radiation syndrome, and as a late-effect cancer. However, in a usual emergency setting, it is unclear how this task can be achieved. Within this study, we evaluated the feasibility of different radiological methods to identify and locate an incorporated radioactive fragment. We placed two different Cs sources and several non-radioactive fragments representing sham control samples within a human spine phantom. Standard emergency imaging procedures were performed, including plane radiography and different CT scans (64 row, 384 row dual energy, 320 row without iterative metal artifact reduction), respectively. Eight radiologists were blinded toward the results and asked to identify the radioactive fragments within the provided images. For both sources, correct identification was rather low (15.63%). Furthermore, none of the questioned radiologists (N = 0) stated that they were able to identify the radioactive shrapnel distinctly. Positive predictive value was accordingly low (15.63%). Most participants recommended a scintigraphy-based technique for identification (26.67%) rather than radiographic procedures (6.67%). Identification and location of incorporated small radioactive fragments with low energies by standard radiological procedures prior to surgical exploration is not promising. Nevertheless, procedures that can achieve this aim are needed direly in the case of a terrorist attack with a radiological dispersal device and should be available in an emergency department.

Gene Expression and Cellular Markers of Occupational Radiation Exposure in Chernobyl Shelter Construction Workers

Low-dose radiation effects were studied in Ukrainian personnel of the Chernobyl exclusion zone. The aim of this study was to determine the influence of borderline exposure to annual professional limits and age on expression of molecular markers. Study groups included 300 radiation workers performing construction work on the New Safe Confinement (Arch) upon the Chernobyl "Shelter" [external dose, 26.1 ± 18.1 mSv; age, 43.1 ± 10.3 y overall and 48.7 ± 5.9 y for 69 control persons]. Methods included gene expression using RT-PCR, flow cytometry of lymphocyte antigens, gamma-H2AX, Cyclin D1 expression, and relative telomere length using flow-FISH. A statistically significant upregulation of VEGFA BAX, DDB2, NFKB1 was shown at doses below 35 mSv. In workers aged under 40 y with doses higher than 35 mSv, an upregulation of 16 genes was revealed-VEGFA, TERF2, TERF1, BIRC5, BAX, TP53, DDB2, CDKN1B, CDKN2A, NFKB2, MAPK14, TGFBR1, MKNK2, CDKN1A, NFKB1, TP53I3; and four genes were downregulated-MADD, FASL, CSF2, and TERT. In workers older than 40 y, 8 genes were upregulated and 12 were downregulated. All groups showed an increased and dose-dependent gamma-H2AX expression. Downregulation of CCND1 genes in older groups was accompanied by lower numbers of Cyclin D1 protein expression and lower CD3 and CD4 cell counts. Upregulation of CSF2 in those over 40 y old positively correlated with B-cell and NK-cell counts. A non-linear type of gene expression response was demonstrated: in doses over 35 mSv for those over 40 y, the increased expression of gamma-H2AX is associated with upregulation of cell survival positive regulators-BIRC5, BRCA1, DDB2, CCND1, TERT genes, and longer telomeres; the younger age group was characterized by TERF1 and TERF2 upregulation and telomere shortening.

Utility of gene expression studies in relation to radiation exposure and clinical outcomes: thyroid cancer in the Ukrainian-American cohort and late health effects in a MAYAK worker cohort

PURPOSE

We herein report on changes in gene expression after radiation exposure to iodine-131 from the Chernobyl accident in the Ukrainian-American thyroid cohort and to external gamma ray or internal plutonium exposure in the Mayak Production Association radiation workers.

MATERIALS AND METHODS

Taking advantage of access to tissue samples from the thyroid cancer cases in the Ukrainian-American cohort, our group tried to identify candidate genes to discriminate spontaneously occurring thyroid cancers from thyroid cancers caused by radiation exposure. We also examined gene expression changes in normal and cancerous thyroid tissue in relation to iodine-131 dose separately. Gene expression changes in the peripheral blood of radiation exposed Mayak workers were examined to elucidate the dose-to-gene and gene-to-health (e.g. cardiovascular disease) relationships.

CONCLUSIONS

Results of both projects are discussed under the aspect of dose-response relationships (dose-to-gene) and clinical outcome relationships (gene-to-effect) in light of how mechanistic data can be translated into actionable knowledge for radiation protection or clinical purposes.

Retrospective biodosimetry techniques: Focus on cytogenetics assays for individuals exposed to ionizing radiation

In the absence of physical data, biodosimetry tools are required for fast dose and risk assessment in the event of radiological or nuclear mass accidents or attacks to triage exposed humans and take immediate medical countermeasures. Biodosimetry tools have mostly been developed for retrospective dose assessment and the follow-up of victims of irradiation. Among them, cytogenetics analyses, to reveal chromosome damage, are the most developed and allow the determination of doses from blood samples as low as 100 mGy. Various cytogenetic tests have already allowed retrospective dose assessment of Chernobyl liquidators and military personnel exposed to nuclear tests after decades. In this review, we discuss the properties of various biodosimetry techniques, such as their sensitivity and limitations as a function of the time from exposure, using multiple examples of nuclear catastrophes or working exposure. Among them, chromosome FISH hybridization, which reveals chromosome translocations, is the most reliable due to the persistence of translocations for decades, whereas dicentric chromosome and micronuclei assays allow rapid and accurate dose assessment a short time after exposure. Both need to be adjusted through mathematical algorithms for retrospective analyses, accounting for the time since exposure and the victims' age. The goal for the future will be to better model chromosome damage, reduce the time to result, and develop new complementary biodosimetry approaches, such as mutation signatures.

CHANGES IN GENE EXPRESSION ASSOCIATED WITH NON-CANCER EFFECTS OF THE CHORNOBYL CLEAN-UP WORKERS IN THE REMOTE PERIOD AFTER EXPOSURE

OBJECTIVE

to establish the connection of radiation-induced changes in gene expression with the realized pathology of the broncho-pulmonary and cardiovascular systems in Chornobyl clean-up workers.

MATERIALS AND METHODS

We examined 314 male Chornobyl clean-up workers (main group; age (58.94 ± 6.82) years(M ± SD); min 33, max 79 years; radiation dose (411.82 ± 625.41) mSv (M ± SD); min 1.74, max 3600 mSv) with various nosological forms of cardiovascular and broncho-pulmonary pathology (BPP) and 50 subjects of the controlgroup: age (50.50 ± 5.73) years (M ± SD); min 41, max 67 years. The relative level of BCL2, CDKN2A, CLSTN2, GSTM1,IFNG, IL1B, MCF2L, SERPINB9, STAT3, TERF1, TERF2, TERT, TNF, TP53, CCND1, CSF2, VEGFA genes expression was determined inperipheral blood leukocytes by real-time PCR (7900 HT Fast Real-Time PCR System (Applied Biosystems, USA)). The«gene-disease» association was determined on statistical models stratified separately for each disease and gene.Logistic regression was used to calculate the odds ratio.

RESULTS

Increased GSTM1 gene expression and no changes in angiogenesis-related VEGFA gene expression werefound in the main group of patients with coronary heart disease (CHD). It was established overexpression of TP53,VEGF and IFNG genes in the group of patients with arterial hypertension (AH). At combination of these diseases anincrease of expression of СSF2, TERF1, TERF2 genes was established. The detected changes demonstrate an activationof the antioxidative defense system in patients with CHD, while AH is associated with the expression of genes ofangiogenesis and immune inflammation. It was shown an increase in the expression of genes associated with apoptosis and kinase activity (BCL2, CLSTN2, CDKN2), immune inflammation (CSF2, IL1B, TNF) in Chornobyl clean-upworkers with BPP. Expression of TP53 and GSTM1 (gene, associated with the glutathione system) was significantlyupregulated in the group of individuals with chronic bronchitis, whereas in patients with chronic obstructive pulmonary disease, no increase was detected; the expression of SERPINB9 and MCF2L genes was downregulated.

CONCLUSIONS

Changes in the expression of genes, associated with the development of somatic pathology in theremote period after irradiation, in particular the genes of the immune response and inflammatory reactions CSF2,IFNG, IL1B, TNF; expression of genes that regulate cell proliferation, aging and apoptosis TP53, BCL2, MCF2L, CDKN2A,SERPINB9, TERF1, TERF2, TERT; genes that regulate cell adhesion and angiogenesis CLSTN2, VEGF.

What does radiation biology tell us about potential health effects at low dose and low dose rates?

The health risks to humans exposed to low dose and low dose rate ionising radiation remain ambiguous and are the subject of debate. The need to establish risk assessment standards based on the mechanisms underlying low dose/low fluence radiation exposures has been recognised by scholarly and regulatory bodies as critical for reducing the uncertainty in predicting adverse health risks of human exposure to low doses of radiation. Here, a brief review of laboratory-based evidence of molecular and biochemical changes induced by low doses and low dose rates of radiation is presented. In particular, two phenomena, namely bystander effects and adaptive responses that may impact low-level radiation health risks, are discussed together with the need for further studies. The expansion of this knowledge by considering the important variables that affect the radiation response (e.g. genetic susceptibility, time after exposure), and using the latest advances in experimental models and bioinformatics tools, may guide epidemiological studies towards reducing the uncertainty in predicting the potential health hazards of exposure to low-dose radiation.

BIOLOGICAL MARKERS OF EXTERNAL AND INTERNAL EXPOSURE IN SHELTER CONSTRUCTION WORKERS: A 13-YEAR EXPERIENCE

OBJECTIVE

The aim of this study is to investigate the cellular, molecular, genetic and non-invasive functional biomarkers of occupational irradiation in workers exposed to a combination of external gamma-radiation and incorporation of transuranium elements.

RESULTS

A study was performed in 688 radiation workers of Shelter object conversion into a safe system with mean shift dose of external exposure of 26.06 mSv (range: 0.1-113.35) and risk of internal exposure with transuranium elements. Several biological parameters could serve as biomarkers of exposure at radiation doses below 100 mSv and even in 20-50 mSv interval. The parallel changes were shown in decline of brain electric activity, telomere length, differences in CCND1, CDKN1A, CDKN2A, VEGFA, TP53, DDB2 genes expression. An increase in counts of dicentrics, pair fragments and TCR-variant lymphocytes at doses over professional limits shows the need of biological dosimetry. The most sensitive markers include TCR-CD4+, γ-H2AX+ and CyclinD1+ cell counts. Implementation of flow cytometry approach for these markers enables quick obtaining of quantitative data. Confounding factors included respiratory function and smoking. The study of the radiation workers with the history of chronic exposure in radiation area during 3-5 years demonstrates changes of compensatory origin, i.e. absence of telomere shortening, increased number of NK-cells in combination with lower expression of intracellular γ-H2AX.

CONCLUSION

This study confirms the presence of radiation-induced changes in gene regulation of cell proliferation, telomere function and apoptosis in radiation workers exposed to external and internal exposure at doses above professional limits and increase of compensatory changes.

Ionizing radiation and taxonomic, functional and evolutionary diversity of bird communities

Ionizing radiation from nuclear accidents at Chernobyl, Fukushima and elsewhere has reduced the abundance, species richness and diversity of ecosystems. Here we analyzed the taxonomic, functional and evolutionary diversity of bird communities in forested areas around Chernobyl. Species richness decreased with increasing radiation, mainly in 2007. Functional richness, but not functional evenness and divergence, decreased with increasing level of ionizing radiation. Evolutionary distinctiveness of bird communities was higher in areas with higher levels of ionizing radiation. Regression tree models revealed that species richness was higher in bird communities in areas with radiation levels lower than 0.7 μSv/h. In contrast, when radiation levels were higher than 16.67 μSv/h, bird species richness reached a minimum. Functional richness was affected by two variables: Forest cover and radiation level. Higher functional richness was found in bird communities in areas with forest cover lower than 50%. In the areas with forest cover higher than 50%, the functional richness was lower when radiation level was higher than 0.91 μSv/h. Finally, the average evolutionary distinctiveness of bird communities was higher in areas with forest cover exceeding 50%. These findings imply that level of ionizing radiation interacted with forest cover to affect species richness and its component parts, i.e. taxonomic, functional, and evolutionary diversity.

Exploring the Link between Radiation Exposure and Multifocal Basal Cell Carcinomas in a Former Chernobyl Clean-up Worker by Combining Different Molecular Biological Techniques

Thirty years after the Chernobyl nuclear power plant accident we report on a patient who was a clean-up worker, who subsequently developed multiple cutaneous basal cell carcinomas (BCCs). We used several methods to assess the biological long-term effects related to low-dose external and internal radiation exposure. Specifically, because BCC risk may be increased with ionizing radiation exposure, we endeavored to determine whether the multifocal BCCs were related to the patient's past clean-up work. We assessed cytogenetic changes using peripheral blood, and internal incorporation was measured with a whole-body counter. Gene expression alterations were determined and array-based comparative genomic hybridization was performed for copy number aberration analysis of available BCC samples. In 1,053 metaphase cells, the dicentric yield of 0.005 dicentrics, with acentrics/cell, was significantly increased compared to the established calibration curve (P < 0.001). A 2.5-fold increase in total translocations was observed compared to the expected translocation rate. No internal contamination was detected with the whole-body counter. At the RNA level, two of seven genes (HNRNPA1, AGAP4/6/8) indicated internal plutonium exposure associated with the lowest dose category found in Mayak workers (>0-0.055 Gy). Relevant DNA copy number changes were only detected within the most aggressive BCC focus. Our results suggest that the examined worker had low and more recent radiation exposure with presumably internalized radionuclides that were below the detection level of a whole-body counter. The multifocal BCC could not be related to past occupational radiation exposure. The findings from our study suggest that integrating different methodologies potentially provides an improved overall assessment of individual health risks associated with or excluding occupational radiation exposure.

Pre-Exposure Gene Expression in Baboons with and without Pancytopenia after Radiation Exposure

Radiosensitivity differs in humans and likely among primates. The reasons are not well known. We examined pre-exposure gene expression in baboons (n = 17) who developed haematologic acute radiation syndrome (HARS) without pancytopenia or a more aggravated HARS with pancytopenia after irradiation. We evaluated gene expression in a two stage study design where stage I comprised a whole genome screen for messenger RNAs (mRNA) (microarray) and detection of 667 microRNAs (miRNA) (real-time quantitative polymerase chain reaction (qRT-PCR) platform). Twenty candidate mRNAs and nine miRNAs were selected for validation in stage II (qRT-PCR). None of the mRNA species could be confirmed during the validation step, but six of the nine selected candidate miRNA remained significantly different during validation. In particular, miR-425-5p (receiver operating characteristic = 0.98; p = 0.0003) showed nearly complete discrimination between HARS groups with and without pancytopenia. Target gene searches of miR-425-5p identified new potential mRNAs and associated biological processes linked with radiosensitivity. We found that one miRNA species examined in pre-exposure blood samples was associated with HARS characterized by pancytopenia and identified new target mRNAs that might reflect differences in radiosensitivity of irradiated normal tissue.

Ionizing radiation biomarkers in epidemiological studies - An update

Recent epidemiology studies highlighted the detrimental health effects of exposure to low dose and low dose rate ionizing radiation (IR): nuclear industry workers studies have shown increased leukaemia and solid tumour risks following cumulative doses of <100mSv and dose rates of <10mGy per year; paediatric patients studies have reported increased leukaemia and brain tumours risks after doses of 30-60mGy from computed tomography scans. Questions arise, however, about the impact of even lower doses and dose rates where classical epidemiological studies have limited power but where subsets within the large cohorts are expected to have an increased risk. Further progress requires integration of biomarkers or bioassays of individual exposure, effects and susceptibility to IR. The European DoReMi (Low Dose Research towards Multidisciplinary Integration) consortium previously reviewed biomarkers for potential use in IR epidemiological studies. Given the increased mechanistic understanding of responses to low dose radiation the current review provides an update covering technical advances and recent studies. A key issue identified is deciding which biomarkers to progress. A roadmap is provided for biomarker development from discovery to implementation and used to summarise the current status of proposed biomarkers for epidemiological studies. Most potential biomarkers remain at the discovery stage and for some there is sufficient evidence that further development is not warranted. One biomarker identified in the final stages of development and as a priority for further research is radiation specific mRNA transcript profiles.

Combining Radiation Epidemiology With Molecular Biology-Changing From Health Risk Estimates to Therapeutic Intervention

The authors herein summarize six presentations dedicated to the key session "molecular radiation epidemiology" of the ConRad meeting 2015. These presentations were chosen in order to highlight the promise when combining conventional radiation epidemiology with molecular biology. Conventional radiation epidemiology uses dose estimates for risk predictions on health. However, combined with molecular biology, dose-dependent bioindicators of effect hold the promise to improve clinical diagnostics and to provide target molecules for potential therapeutic intervention. One out of the six presentations exemplified the use of radiation-induced molecular changes as biomarkers of exposure by measuring stabile chromosomal translocations. The remaining five presentations focused on molecular changes used as bioindicators of the effect. These bioindicators of the effect could be used for diagnostic purposes on colon cancers (genomic instability), thyroid cancer (CLIP2), or head and neck squamous cell cancers. Therapeutic implications of gene expression changes were examined in Chernobyl thyroid cancer victims and Mayak workers.

Transcriptome Alterations In X-Irradiated Human Gingiva Fibroblasts

Ionizing radiation is known to induce genomic lesions, such as DNA double strand breaks, whose repair can lead to mutations that can modulate cellular and organismal fate. Soon after radiation exposure, cells induce transcriptional changes and alterations of cell cycle programs to respond to the received DNA damage. Radiation-induced mutations occur through misrepair in a stochastic manner and increase the risk of developing cancers years after the incident, especially after high dose radiation exposures. Here, the authors analyzed the transcriptomic response of primary human gingival fibroblasts exposed to increasing doses of acute high dose-rate x rays. In the dataset obtained after 0.5 and 5 Gy x-ray exposures and two different repair intervals (0.5 h and 16 h), the authors discovered several radiation-induced fusion transcripts in conjunction with dose-dependent gene expression changes involving a total of 3,383 genes. Principal component analysis of repeated experiments revealed that the duration of the post-exposure repair intervals had a stronger impact than irradiation dose. Subsequent overrepresentation analyses showed a number of KEGG gene sets and WikiPathways, including pathways known to relate to radioresistance in fibroblasts (Wnt, integrin signaling). Moreover, a significant radiation-induced modulation of microRNA targets was detected. The data sets on IR-induced transcriptomic alterations in primary gingival fibroblasts will facilitate genomic comparisons in various genotoxic exposure scenarios.