Global Metabolomic Identification of Long-Term Dose-Dependent Urinary Biomarkers in Nonhuman Primates Exposed to Ionizing Radiation

Abstract

Due to concerns surrounding potential large-scale radiological events, there is a need to determine robust radiation signatures for the rapid identification of exposed individuals, which can then be used to guide the development of compact field deployable instruments to assess individual dose. Metabolomics provides a technology to process easily accessible biofluids and determine rigorous quantitative radiation biomarkers with mass spectrometry (MS) platforms. While multiple studies have utilized murine models to determine radiation biomarkers, limited studies have profiled nonhuman primate (NHP) metabolic radiation signatures. In addition, these studies have concentrated on short-term biomarkers (i.e., <72 h). The current study addresses the need for biomarkers beyond 72 h using a NHP model. Urine samples were collected at 7 days postirradiation (2, 4, 6, 7 and 10 Gy) and processed with ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight (QTOF) MS, acquiring global metabolomic radiation signatures. Multivariate data analysis revealed clear separation between control and irradiated groups. Thirteen biomarkers exhibiting a dose response were validated with tandem MS. There was significantly higher excretion of L-carnitine, L-acetylcarnitine, xanthine and xanthosine in males versus females. Metabolites validated in this study suggest perturbation of several pathways including fatty acid β oxidation, tryptophan metabolism, purine catabolism, taurine metabolism and steroid hormone biosynthesis. In this novel study we detected long-term biomarkers in a NHP model after exposure to radiation and demonstrate differences between sexes using UPLC-QTOF-MS-based metabolomics technology.

Assessment of Saliva as a Potential Biofluid for Biodosimetry: A Pilot Metabolomics Study in Mice

“…Finally, while this proof-of-concept study in mice did provide valuable information on the utility of saliva as a biofluid for biodosimetry, the radiation signature should be further assessed in nonhuman primates and the human population, as has been done previously with urine (5, 8, 24). …”

“…Supernatant (5 μl) were diluted in 50:50 acetonitrile:water (1:20 dilution) with internal standards (4 μ M debrisoquine sulfate, 30 μ M 4-nitrobenzoic acid) and centrifuged for 20 min at 13,000 g , 4°C and 2 μl were then injected into a Waters ® Acquity UPLC ® High Strength Silica, 1.8 μm, 50 mm column (Waters Corp., Milford, MA) with LC-MS conditions as described previously (5, 8). Data were acquired on a Waters UPLC coupled to a Xevo ® G2 QTof, operated in both ESI + and ESI − .…”

“…To date, we have explored the value of such markers in rodents, nonhuman primates, and total-body-irradiated humans with very encouraging results and significant cross-species validation (4–8). In this pilot study, we extended our studies to assess the utility of saliva as a biofluid for biodosimetry through metabolomics at day 1 and 7 postirradiation, time points that have been previously investigated with other biofluids (1, 4, 6, 7, 9–11).…”

Nuclear Abnormalities of Lymphocytes as the Simplest Markers for Bioindication Test in Case of Mass Casualty Events Involving Radiation Exposure

“…Frequency of occurrence of cells with dumbbell-shaped nuclei depends on the dose of irradiation and this correlation is described by a linearquadratic function with the following equation: y = 0.003+0.014x +0.005x 2 [31]. We would like to emphasize that the simplest biomarkers (nuclei abnormalities) we suggest for radiation exposure detection in vivo is not an alternative to classical radiation biomarkers in vitro [17], as well as to other modern approaches [2][3][4][5][44][45][46]. Detection of chromosomal aberrations (dicentrics) and the cytochalasine B micronucleus and "Cytome" methods are reliable bioindication and biodosimetry methods.…”

“…The field of activity of biodosimetry has significantly expanded with the methods of genomics [1,2], proteomics [3,4], metabolomics [5] and transcriptomics [6]. At the same time, methods of cytogenetics that require the cultivation of lymphocytes in vitro or the use of special equipment still remain the classical methods [7][8][9][10][11][12][13].…”