PARENT SESSION

Cell and Tissue Signaling

(PP258) Biomarkers of radiation exposure and stress based on individual responsiveness.

Segura, Tamika^*,1, Prud'homme-Lalonde, Louise¹, Lachapelle, Sylvie¹, Mullins, Dana¹, Qutob, Sami², Thorleifson, Erika², Lemyre, Louise³, Wilkinson, Diana¹, ¹ Radiological Analysis & Defence;, Ottawa, Ontario, Canada² Consumer and Clinical Radiation Protection Bureau;, Ottawa, Ontario, Canada³ Institute of Population Health;, Ottawa, Ontario, Canada

ABSTRACT- A major advantage of cytogenetics based assays is that they provide a dose estimate in radiation exposure cases where physical dosimetry is unavailable or in dispute. A fundamental disadvantage however, is that these dosimetry assessments do not account for variation in biological consequences of exposure. From radiotherapy data it has become evident that exposed individuals do not respond in a predefined manner to a given dose. Our hypothesis is that biomarkers of radiation exposure will be identified and that these biomarkers will become screening tools for identification of radiation exposed individuals based on their unique radiation responsiveness. This work has been expanded to examine not only the affects of radiation, but also how psychological stress in combination with radiation may affect these radiation responsive markers. This information is critical for determining the specificity of the selected biomarkers. To study the biomarker profiles after radiation, five 3 ml venous blood samples were taken from 14 healthy donors. Each tube was given an in vitro dose of either 0, 0.1, 0.5, 1.0 or 2.0 Gy using a ⁶⁰Cobalt source with a dose rate of 6 Gy/h. After 24h the plasma was separated and assayed using the Bioplex protein suspension array system. To study the biomarker profiles due to stress, 14 volunteers donated blood as stated above both during a stressful event and then again 4 weeks after the event. The cytokine biomarkers currently under investigation include IL-1, IL-2, IL-6, IL-8, IL-10, IL-12, G-CSF, GM-CSF, and TNF-. Our data shows that i) basal levels of cytokines are not always consistent between individuals, ii) some individuals do have a dose response relationship for certain cytokine levels in response to radiation and iii) most individuals were immunosuppressed when stressed compared to their personal cytokine levels four weeks post-event. The outcome of this research will contribute to the development of a new tool in counter-terrorism and radiological nuclear response of benefit for both screening military and civilian personnel with the hope that we can distinguish between a biological response to stress and radiation. A rapid surveillance tool can ensure that the general public and/or the military will receive the proper urgently needed care after a radiation incident.

Key words: Biomarker, Cytokine, Radiological Terrorism, Radiation Exposure