Research ArticleBIODOSIMETRY

Two-miRNA–based finger-stick assay for estimation of absorbed ionizing radiation dose

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Science Translational Medicine  15 Jul 2020:
Vol. 12, Issue 552, eaaw5831
DOI: 10.1126/scitranslmed.aaw5831

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Detecting radiation in a single drop

Practical, scalable approaches for measuring therapeutic or accidental ionizing radiation exposure are needed. Yadav et al. show that the expression of two miRNAs in a drop of blood allowed inference of recent gamma or neutron radiation exposure in a variety of mouse models subjected to fractionated or single acute radiation and patients with leukemia undergoing fractionated radiotherapy within a few hours after blood collection. Although validation in nonhuman primates and testing of mixed-field exposure is needed, this simple two-miRNA assay shows preclinical promise for estimating radiation exposure at a range of doses relevant to clinical and catastrophic radiation exposure in humans.

Abstract

Nuclear radiation and radioactive fallouts resulting from a nuclear weapon detonation or reactor accidents could result in injuries affecting multiple sensitive organs, defined as acute radiation syndrome (ARS). Rapid and early estimation of injuries to sensitive organs using markers of radiation response is critical for identifying individuals who could potentially exhibit ARS; however, there are currently no biodosimetry assays approved for human use. We developed a sensitive microRNA (miRNA)–based blood test for radiation dose reconstruction with ±0.5 Gy resolution at critical dose range. Radiation dose–dependent changes in miR-150-5p in blood were internally normalized by a miRNA, miR-23a-3p, that was nonresponsive to radiation. miR-23a-3p was not highly expressed in blood cells but was abundant in circulation and was released primarily from the lung. Our assay showed the capability for dose estimation within hours to 1 week after exposure using a drop of blood from mice. We tested this biodosimetry assay for estimation of absorbed ionizing radiation dose in mice of varying ages and after exposure to both improvised nuclear device (IND)–spectrum neutrons and gamma rays. Leukemia specimens from patients exposed to fractionated radiation showed depletion of miR-150-5p in blood. We bridged the exposure of these patients to fractionated radiation by comparing responses after fractionated versus single acute exposure in mice. Although validation in nonhuman primates is needed, this proof-of-concept study suggests the potential utility of this assay in radiation disaster management and clinical applications.

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