Biodosimetry (USUHS)
Abstract
For the Uniformed Services University of the Health Sciences (USU), the mission and research objectives for biodosimetry are to assess radiation exposure by developing and providing biological and biophysical dosimetry capabilities for acute, protracted, and prior radiation exposures for all relevant military applications. FY 2018 Plans: -Establish a suite of biodosimetry assays, techniques, and standard operating procedures to support analysis of chromosomal aberrations for assessing radiation injury and dose. -Establish dose-response curve for dicentric yields, that is, frequencies of chromosome aberrations in irradiated lymphocytes using automated dicentric scoring software utility. -Perform dose response studies to measure dicentric chromosomal aberrations in irradiated lymphocytes after exposure to mixed neutron and photon radiation fields mimicking those from an improvised nuclear device at relevant distances from the epicenter. -Identify radiation-responsive biological markers (aka biomarkers) such as microRNAs and proteins that are organ-specific in a mouse model of partial-body radiation exposure. -Participate in annual performance evaluation of established techniques and procedures for radiation biodosimetry to demonstrate accuracy in dose assessment methodology such as cytogenetic assays for detecting chromosomal aberrations; implement new approaches through reassessment to enhance throughput capability for processing and scoring of chromosomal aberrations. -Establish partial-body animal radiation mouse model of acute radiation syndrome (ARS) using low linear energy transfer( LET)/photon exposure from the small animal radiation research platform (SARRP) and assess organ-specific radiation injury biomarkers similar to ones performed earlier in low-linear energy transfer (LET) Total-body irradiation (TBI) mouse model. -Establish partial-body animal radiation models (mouse and nonhuman primates (NHPs)) using low-LET/photon exposure with the SARRP for mice and with the linear accelerator (LINAC) radiation platform for NHPs in order to assess organ-specific radiation injury biomarkers evaluated earlier in low-LET TBI studies. -Establish mouse TBI model for combined hematological and proteomic biodosimetry approach following mixed-field (neutrons and photons, high-LET) in addition to one already established and evaluated for a pure photon (60 Co gamma ray, low-LET) exposure. -Evaluate IL-18 and IL-12, small protein signaling agents as dual radiation biomarkers in non-human primate urine sampling for assessment of radiation injury and doses, severity and lethality after TBI. -Develop microRNAs profile as biomarkers of radiation injury and dose by sampling urine from gamma-irradiated NHPs using microRNAs microarray and quantitative real-time polymerase chain reaction (RT-PCR) methods. -Compare microRNAs profiles in gamma-irradiated mouse serum and NHPs urine and identify sensitive and accurate radiation biomarkers. -Evaluate effects of low and moderate doses of gamma-radiation from hematopoietic and immune system of mice (in vivo) and human cells (in vitro). -Further evaluate mechanisms of radiation-induced lymphocyte damage. -Further evaluate additional hematology and leukemia biomarkers during leukemogenesis that are differentially expressed at early and late phases of transformation. Identify additional epigenetic changes that discriminate between differences in dose rate at low doses (<10 cGy). FY 2018 Accomplishments: - Evaluated several radiation-responsive protein biomarkers for early-phase and organ-specific damage in animal total-body irradiation (TBI) models: In mouse (with minimal supportive care) and nonhuman primate (with minimal and full medical supportive care consisting of G-CSF or Neupogen® [filgrastim], antibiotics, blood transfusions, etc.]) in order to predict as early as possible the radiation-induced multi-organ involvement (MOI) and multi-organ failure (MOF) and late effects of exposure and acute radiation sickness (ARS) outcome in two animal models to support FDA regulatory requirement. -Demonstrated in mouse TBI studies that the evaluated biomarker profiles show no gender-effect as well as no dose-rate effect within a broad range (0.02 to ~2 Gy/min) reflecting the fact that the radiation dose prediction might be done strictly based on biomarker level regardless to the exposure dose-rate. -Identified several biomarkers of gastrointestinal (GI) injury: citrulline, citrullinated proteins (CP), bactericidal permeability increasing (BPI) protein, lipopolysaccharide binding protein (LBP), procalcitonin (PCT), intestinal fatty acid binding protein (I-FABP), diamine oxidase (DAO or histaminase) in mouse and nonhuman primate (NHP) TBI models. -Plasma citrulline and citrullinated proteins were identified as early biomarkers of radiation-induced gastrointestinal damage and a potential new biomarkers of late-effect kidney failure. -Citrullinated proteins were demonstrated as a new predicative radiation-responsive biomarker in animal models for a prediction of the ARS outcome (AFRRI US Patent Number 9,063,148 issued on 6/23/2015). -Evaluated biochemical profiles in NHP TBI model revealed elevations in individual enzymes that reflect radiation-damage to the respective organs (i.e., salivary glands, pancreas, liver, muscles, kidney, etc.). -Confirmed that the specific biomarker levels correlate with a severity of radiation damage to different organs evaluated in complete necropsies performed in NHPs. Although, those findings need to evaluate in partial-body animal studies using either SARRP or LINAC. -Evaluated the IL-18 level in urine of NHPs total-body irradiated with 60Co gamma-rays and demonstrated its great utility as a non-invasive early prognostic indicator of survival facilitated rapid detection of radiation exposure that might be suitable for field-deployable biodosimetry point-of-care to determine the exposure dose in a few minutes. -Demonstrated that the urine IL-18 levels combined with other biomarkers measured in blood provided highly discriminatory power, specificity and sensitivity of radiation exposure. -Created ARS severity score response categories in mouse and NHP TBI gamma-rays studies reveled good similarities with one created in radiation accident victims. -Completed comparison of some results/data from the NHP dose-response TBI (gamma- and x-rays) studies with data collected in radiation accident victims and radiation therapy patients and revealed good similarities. -Evaluated and demonstrated the different responses of mouse hematopoietic and immune cells to low-moderate doses (0.1, 0.5, 1.0, 3.0, and 5.0 Gy) of total-body γ-irradiation (TBI). Radiation < 1 Gy can significantly damage hematopoietic stem and progenitor cells; low dose radiation-induced decrease of stem cell factor (SCF) in mouse BM and increase in circulating proinflammatory factors may be responsible for the enhanced sensitivity of hematopoietic stem and progenitor cells to radiation. -Developed a novel method, using long-range quantitative PCR to determine radiation-induced nuclear and mitochondria DNA damage. -Demonstrated the circulating microRNA (miR)-30 and miR-34 as radiation biomarkers in mice which can also be used to track radiation-induced apoptosis in human and mouse cells. - Established the severity of mortality and platelet depletion dependence on radiation doses and dose rates. - Established the severity of lymphocyte depletion and concentrations of biomarkers G-CSF, IL-18, Flt-3 ligand dependence on radiation doses. -Established two radiation dose-response calibration curves (60Co-gamma rays at 0.6 Gy/min and 0.1 Gy/min) for automated scoring of dicentrics chromosome aberrations (DCA) that enable rapid radiation dose assessment. These studies contribute towards DoDs radiological medical preparedness by validating enhanced throughput capability via automated scoring software and laboratory competency. -Reported on radiation dose-responses for both total-body and partial-body irradiation up to 30 Gy using the premature chromosome condensation (PCC) assay using multiple endpoints (i.e., excess fragments, rings, length ratio, and dicentrics). On-going studies are evaluating the accuracy of these various endpoints using the PCC assay using blind samples. -Participated as a satellite scoring laboratory in the RENEB (Realizing the European Network in Biodosimetry) RENEB ILC II exercise involving the analysis of 500 spreads in each of three samples. Preliminary analysis showed samples that our results were to be within in the acceptable range. Participated in intra- and inter-laboratory DCA/dose assessment comparison exercises with Health Canada. (Dr. Ruth Wilkins). This exercise involved the use of 10 human blood samples (exposed to various radiation doses) received from Health Canada that were cultured, stained, and scored for dicentrics using their requested triage scoring approach (n=50). Data analysis is on-going. -Initiated studies to compare total-body and partial-body radiation exposures using the mouse model system to evaluate candidate radiation biomarkers (i.e., proteomic, miRNA) to assess organ specific injury. - Reported new research findings that increases in biomarkers from blood after mixed field irradiation and gamma irradiation depended on radiation doses but not radiation dose rates. The effects also were not affected by genders. The observation is essential for establishing the biomarkers for triage and radiation dose assessment. One paper on this subject was published in Radiation Research 189:634-643, 2018.
Document Details
- Document Type
- Accomplishment
- Publication Date
- Oct 01, 2020
- Source ID
- 0859c3647750889bd38df688e6d57038