title: Cellular adaptive response to chronic radiation exposure in interventional cardiologists.
abstract: Aims Invasive cardiologists are the most exposed to ionizing radiation among health professionals and show an increased rate of somatic DNA damage. To evaluate the effects of chronic low-dose exposure to ionizing radiation on redox state and apoptotic activation.  Methods and results We enrolled 10 healthy exposed professionals (all interventional cardiologists, Group II, exposed: age = 38 ± 5 years) and 10 age- and gender-matched unexposed controls (Group I, non-exposed). Exposed subjects had a median exposure of 4 mSv/year (range 1-8) by film badge dosimetry (below lead apron). We measured reduced glutathione (GSH, a marker of antioxidant response) in erythrocytes and plasma generation of hydrogen peroxide (a marker of oxyradical stress) by ferrous oxidation-xylenol orange assay in plasma. In both groups, lymphocytes were isolated and caspase-3 activity (a marker of apoptotic response) measured at baseline and following 2 Gy in vitro irradiation. Exposed subjects showed a three-fold increase in hydrogen peroxide (Group I = 2.21 ± 1.03 vs. II = 6.51 ± 1.55 μM H(2)O(2) equivalents) and a 1.7-fold increase in GSH (I = 12.37 ± 1.22 vs. II = 20.61 ± 2.16 mM). Exposed subjects also showed higher values of caspase-3 activity, both at baseline and-more strikingly-following high-dose radiation challenge.  Conclusion In interventional cardiologists, chronic exposure to low-dose radiation is associated with an altered redox balance mirrored by an increase in hydrogen peroxide and with two possibly adaptive cellular responses: (i) an enhanced antioxidant defence (increase in GSH, counteracting increased oxyradical stress) and (ii) an increased susceptibility to apoptotic induction which might efficiently remove genetically damaged cells.
authors.affiliation: Institute of Food Sciences, National Research Council, Via Roma 64, Avellino, Italy.
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Russo
authors.forename: Idolo
authors.initials: I
authors.lastname: Tedesco
authors.forename: Maria
authors.initials: M
authors.lastname: Russo
authors.forename: Angelo
authors.initials: A
authors.lastname: Cioppa
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Andreassi
authors.forename: Eugenio
authors.initials: E
authors.lastname: Picano
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000528:radiation effects*; D015415:Biomarkers / Q000378:metabolism; D002309:Cardiology; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism; D004912:Erythrocytes / Q000737:chemistry / Q000528:radiation effects; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008297:Male; D016273:Occupational Exposure / Q000009:adverse effects*; D010084:Oxidation-Reduction / Q000528:radiation effects*; D011829:Radiation Dosage; D011839:Radiation, Ionizing; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D017382:Reactive Oxygen Species; D053148:Caspase 3; D005978:Glutathione