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All three proteasome inhibitors showed antioxidant effects in PBMC and up-regulated the antioxidant enzymes MnSOD, catalase and GST-π and the stress protein Hsp70, modifying the early radiation response, and conferring protection against the effects of ionizing radiation.

ABSTRACT Chronic inflammation is a common denominator linking a wide range of health conditions, including tissue response to radiation exposure. This pilot study investigates whether inflammatory cytokines—interleukins IL-6, −8, −10, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor α (TNFα)—can be used as early biomarkers of radiation-induced adverse health effects in occupationally exposed individuals. The study included 33 workers externally exposed to gamma radiation from the nuclear industry with cumulated doses from 0.11 to 190 mSv and 42 non-exposed controls of comparable age and socio-economic status. IL-6, IL-8, MCP-1, TNFα and IL-10 were analyzed by enzyme-linked assay (ELISA) in blood plasma samples. Total antioxidant status (TAS) of blood plasma was determined by a colorimetric assay. The radiation-exposed and control groups measured significantly different levels of MCP-1, TNFα and IL-10. Seventy-five percent of radiation workers had either high MCP-1 levels or low IL-10 levels and 30% had all three cytokines dysregulated. Approximately 50% of workers showed upregulated antioxidant status, which appeared to compensate the pro-inflammatory cytokine shift in these individuals. In contrast, only 2% of the control subjects were found to have three dysregulated cytokines, and all of them measured within the normal TAS range. The present study may represent an important step towards the establishment of a reliable set of biomarkers for health-risk estimation in population cohorts exposed to low radiation doses.

Purpose Radiation exposure, besides the risk of cancer, may also increase the risk of non-cancer diseases, including cardiovascular disease (CVD). This study investigates whether the soluble form of the ST2 receptor (sST2), an emerging prognostic marker in patients with CVD, can be used to monitor the CVD risk in individuals occupationally exposed to radiation. Materials and methods sST2 in blood plasma from 69 individuals, 45 workers from the nuclear industry and 24 controls, was analyzed using enzyme-linked assay (ELISA). Total antioxidant status (TAS) of blood plasma and levels of reactive oxygen species (ROS) in lymphocytes were determined by colorimetric and fluorescence assays. Results The data suggest a 5-fold increase in the number of subjects with sST2 levels above the clinical threshold and a 10-fold increase in the number of subjects with TAS levels outside the reference range in the exposed group when compared to the group of non-exposed individuals. The strongest up-regulation of TAS was measured in the group of younger workers with cumulative doses not exceeding 50 mSv. Conclusion The present study may represent an initial step towards the establishment of sST2 as a biomarker for CVD risk estimation in the context of radiation exposure.

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