Comparable dose estimates of blinded whole blood samples are obtained independently of culture conditions and analytical approaches. Second RENEB gene expression study.

PURPOSE: This collaboration of five established European gene expression labs investigated the potential impact of culture conditions on the transcriptional response of peripheral blood to radiation exposure. MATERIALS AND METHODS: Blood from one healthy donor was exposed ex vivo to a Cobalt 60 source to produce a calibration curve in addition to four unknown doses. After exposure, the blood samples were either diluted with RPMI medium or left untouched. After 24-h incubation at 37 °C the diluted blood samples were lysed, while the undiluted samples were mixed with the preservative RNALater and all samples were shipped frozen to the participating labs. Samples were processed by each lab using microarray (one lab) and QRT-PCR (four labs). RESULTS: We show that although culture conditions affect the total amount of RNA recovered (p < .0001) and its integrity (p < .0001), it does not significantly affect dose estimates (except for the true dose at 1.1 Gy). Most importantly, the different analysis approaches provide comparable mean absolute difference of estimated doses relative to the true doses (p = .9) and number of out of range (>0.5 Gy) measurements (p = .6). CONCLUSION: This study confirms the robustness of gene expression as a method for biological dosimetry.

Integration of new biological and physical retrospective dosimetry methods into EU emergency response plans - joint RENEB and EURADOS inter-laboratory comparisons.

PURPOSE: RENEB, 'Realising the European Network of Biodosimetry and Physical Retrospective Dosimetry,' is a network for research and emergency response mutual assistance in biodosimetry within the EU. Within this extremely active network, a number of new dosimetry methods have recently been proposed or developed. There is a requirement to test and/or validate these candidate techniques and inter-comparison exercises are a well-established method for such validation. MATERIALS AND METHODS: The authors present details of inter-comparisons of four such new methods: dicentric chromosome analysis including telomere and centromere staining; the gene expression assay carried out in whole blood; Raman spectroscopy on blood lymphocytes, and detection of radiation-induced thermoluminescent signals in glass screens taken from mobile phones. RESULTS: In general the results show good agreement between the laboratories and methods within the expected levels of uncertainty, and thus demonstrate that there is a lot of potential for each of the candidate techniques. CONCLUSIONS: Further work is required before the new methods can be included within the suite of reliable dosimetry methods for use by RENEB partners and others in routine and emergency response scenarios.

MicroRNA Expression for Early Prediction of Late Occurring Hematologic Acute Radiation Syndrome in Baboons.

For effective medical management of radiation-exposed persons after a radiological/nuclear event, blood-based screening measures in the first few days that could predict hematologic acute radiation syndrome (HARS) are needed. For HARS severity prediction, we used microRNA (miRNA) expression changes measured on days one and two after irradiation in a baboon model. Eighteen baboons underwent different patterns of partial or total body irradiation, corresponding to an equivalent dose of 2.5 or 5 Gy. According to changes in blood cell counts (BCC) the surviving baboons (n = 17) exhibited mild (H1-2, n = 4) or more severe (H2-3, n = 13) HARS. In a two Stage study design we screened 667 miRNAs using a quantitative real-time polymerase chain reaction (qRT-PCR) platform. In Stage II we validated candidates where miRNAs had to show a similar regulation (up- or down-regulated) and a significant 2-fold miRNA expression difference over H0. Seventy-two candidate miRNAs (42 for H1-2 and 30 for H2-3) were forwarded for validation. Forty-two of the H1-2 miRNA candidates from the screening phase entered the validation step and 20 of them showed a statistically significant 2-4 fold up-regulation relative to the unexposed reference (H0). Fifteen of the 30 H2-3 miRNAs were validated in Stage II. All miRNAs appeared 2-3 fold down-regulated over H0 and allowed an almost complete separation of HARS categories; the strongest candidate, miR-342-3p, showed a sustained and 10-fold down-regulation on both days 1 and 2. In summary, our data support the medical decision making of the HARS even within the first two days after exposure where diagnostic tools for early medical decision are required but so far missing. The miRNA species identified and in particular miR-342-3p add to the previously identified mRNAs and complete the portfolio of identified mRNA and miRNA transcripts for HARS prediction and medical management.

Association of radiation-induced genes with noncancer chronic diseases in Mayak workers occupationally exposed to prolonged radiation.

We examined the association of gene expression with noncancer chronic disease outcomes in Mayak nuclear weapons plant workers who were exposed to radiation due to their occupation. We conducted a cross-sectional study with selection based on radiation exposure status of Mayak plant workers living in Ozyorsk who were alive in 2011 and either exposed to: combined incorporated Plutonium-239 ((239)Pu) and external gamma-ray exposure (n = 82); external gamma-ray exposure alone (n = 18); or were unexposed (n = 50) of Ozyorsk residents who provided community-based professional support for plant personnel and who were alive in 2011. Peripheral blood was taken and RNA was isolated and then converted into cDNA and stored at -20°C. In a previous analysis we screened the whole genome for radiation-associated candidate genes, and validated 15 mRNAs and 15 microRNAs using qRT-PCR. In the current analysis we examined the association of these genes with 15 different chronic diseases on 92 samples (47 males, 45 females). We examined the radiation-to-gene and gene-to-disease associations in statistical models stratified by gender and separately for each disease and exposure. We modeled radiation exposure as gamma or (239)Pu on both the continuous and categorical scales. Unconditional logistic regression was used to calculate odds ratios (OR), 95% confidence intervals (CI), and the concordance for genes that were significantly associated with radiation exposure and a specific disease outcome were identified. Altogether 12 mRNAs and 9 microRNAs appeared to be significantly associated with 6 diseases, including thyroid diseases (3 genes, OR: 1.2-5.1, concordance: 71-78%), atherosclerotic diseases (4 genes, OR: 2.5-10, concordance: 70-75%), kidney diseases (6 genes, OR: 1.3-8.6, concordance: 69-85%), cholelithiasis (3 genes, OR: 0.2-0.3, concordance: 74-75%), benign tumors [1 gene (AGAP4), OR: 3.7, concordance: 81%] and chronic radiation syndrome (4 genes, OR: 2.5-4.3, concordance: 70-99%). Further associations were found for systolic blood pressure (6 genes, OR: 3.7-10.6, concordance: 81-88%) and body mass index [1 gene (miR-484), OR: 3.7, concordance: 81%]. All associations were gender and exposure dependent. These findings suggest that gene expression changes observed after occupational prolonged radiation exposures may increase the risk for certain noncancer chronic diseases.