Human lymphocytes responses to low and high doses of Iodine-131. Antonina Cebulska-Wasilewska

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1 Human lymphocytes responses to low and high doses of Iodine-131 Antonina Cebulska-Wasilewska The H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences Krakow, Poland ConRad 2013, BMA, Munich, Germany

2 Biological markers, associated with environmentally induced genotoxic changes, are supposed to be useful tools for improving the prediction of risk to human health posed by environmental (biological, chemical, physical) exposure.

3 The desirable features of biological marker (BM) of genotoxic action (GA) are that it should indicate: a quantitative measure of GA, it should be associated with a pathogenic outcome or health risk death Prevalence Biochemical markers, symptom of diseases Biochemical changes of uncertain outcome Internal dose Biomarker Exposure-emergency Any factors (genetic, epigenetic) or genotoxic agents causing a possible interaction (adaptive, additive or synergistic) altering a final biological endpoints that are associated to health risk should not be neglected!

4 How looks our quantitative measures of radiation s genotoxic action(ga) detected by chromosome aberrations (CSA) in HBL?

5 EC Medical Research Reactor, Petten,NL Chromosome aberration frequency Human lymphocytes ( X- r ays, neut r ons) Neutrons,cyclotron, 5,6 MeV,INP,Krakow,PL Retrospective biological dosimetry Californium 252, Gamma rays, Krakow,PL BNL Medical Research Reactor, NY, US Dose [Gy] Our standardizing dose response curves for various therapeutic sources of radiation Cebulska-Wasilewska A., et al.. (1998) Nukleonika V.43, No 1, X- 5. Cf E C B R

6 How our cytogentics results from human monitoring studies are related to the health risks?

7 European follow up studies have shown an association of cytogenetic damage (CA, MN) with cancer incidence outcomes. prob.di Survival sopravvivenza probability 1 0,8 0,6 0,4 0,2 0 Pooled cohort study of subjects from 11 countries (including 550 subjects from our research in the INP, Polish Academy of Sciences, Krakow) lunghezza Follow del up (years) follow-up CA frequency ACsenzaGAP >2 p < Norppa H,.. Cebulska-Wasilewska A. et al., (2006 ). CA and SCEs as biomarker of cancer risk. Mutat Res.600(1-2): Cebulska-Wasilewska A., Rachtan J., et al., (2006) Cytogenetic damage detected in lymphocytes of donors from Małopolska Region in Poland and cancer incidence in the follow-up studies, Springer Vlg), ISBN: , 53. Boffetta P, Norppa H., Cebulska-Wasilewska A., et al., (2007) CA and cancer risk: results of a cohort study from Central Europe. Am. J. Epidemiol;165(1):36-43,. Bonassi S.,.. Cebulska-Wasilewska A., et al., and Boffetta P.,(2008) CA frequency in lymphocytes predicts the risk of cancer: results from a pooled cohort study of subjects in 11 countries, Carcinogenesis vol.29 no

8 Association between our cytogenetic results and cancer risk Cumulative survival Cox, RR=2,6 (95%, CI:1,03-5,55) p<0.022 CA: L<0,67, H>0,67 Polish group (N=385 smoking males out of 550 subjects) Polish group: N=385 (M), age:15-83 ( ) Follow up (years) Cebulska-Wasilewska A., Rachtan J.,Rudek Z.Drąg Z, (2006) Cytogenetic damage detected in lymphocytes of donors from Małopolska Region in Poland and cancer incidence in the follow-up studies Springer Vlg) ISBN:

9 Can we predict susceptibility to exposure, or health risk for individuals potentially exposed to high dose of radiation? Can we distinguish between the stochastic and deterministic exposure?

10 Scheme of the studies on biomarkers of health risk and individual susceptibility to radiation G-0 response cellular response Molecular Cytogenetic Isolated lymphocytes Whole blood samples Challenging in In vivo vitro In vivo X-rays X-rays repair Cytogenetic culturing DNA damage (SCGE assay) CA, FISH, SCE, MN The same procedures we have applied for 3 groups of subjects: diagnosed and treated with I-131 and untreated control

11 Aim of recent studies: a) Molecular and cytogenetic damage induced by low versus high doses of Iodine-131 and versus control b) Susceptibility to radiation and DNA repair efficiency of lymphocytes from people exposed to low and high doses of 131-iodine v. control 41 exposed to 131 I - low dose ( A Av = MBq) Dose Av ~0.07 Sv 37 exposed to 131 I - high dose (A Av = MBq) Dose Av ~11 Sv Control (50 persons) Blood samples were collected after diagnosis (before therapeutic treatment) and 5 weeks after therapeutic dose

12 Kinetics of the post irradiation repair process TM t(1/2)=2.60 t(1/2)=4.54 t(1/2)=4.99 y d =y 0 *e -a*t t(incubation time) [min] Figure shows: a fast DNA repair in G 0 cells (last 2-5 minutes) different repair rates for various subjects different levels of the DNA damage not repaired during post irradiation incubation (residuals) incubations longer than 1h do not decrease anymore the amount of the residual DNA damage detected by SCGE We have studied: 750 healthy subjects and 210 patients (PCP, BPH, CC, GB) and recently thyroid patients exposed to low and high doses of I-131

13 To study inter-individual variability in radiosensitivity and efficiency to repair the DNA damage we proposed challenging dose and single cell gel electrophoresis (SCGE) assay: DONOR S SAMPLE Suspension of lymphocytes in PBS Internal STANDARD Viability test Challenging TREATMENT: X-irradiation on ice, total dose 2 Gy, time 2 min damage in vivo Repair Incubation 1 hr, 37 0 C, medium: 80% RPMI, 20% FCS SCGE assay (COMET) Standardized DNA repair competence assay Cebulska-Wasilewska A., et al.,eur.j. of Occup. & Environ. Medicine; 6(4) , 2000, Mutation Res. 2003

14 Can we predict susceptibility to exposure, or health risk for individuals potentially exposed to high dose of radiation? Can we distinguish between the stochastic and deterministic exposure?

15 Post-challenging DNA damage which was not repaired (% of residual) by 1h incubation (RD (T-DNA) ) shown as dispersion from the mean value of the control group. (Low 131 I dose range: MBq Lower repair capacity the lowest Higher repair capacity the highest Subject s sample code Variability between subjects after diagnostic dose of 131 Iodine (almost 70 % of subjects are stimulated to more efficient DNA repair induced by challening dose) Adaptive response?

16 Variability between individual s DNA repair competence shown as a dispersion from the mean value for control group after exposure to high dose (therapeutic) of 131 Iodine lower repair capacity +2SD Higher repair capacity Subject s samples codes

17 How looks inter-individuals variability in cytogenetic damage induced by low and high dose of radiation?

18 Chromosome aberrations/in 100 cells CSA range: 1-14! CSA range: I Diagnostic range: 1,85-4,85 MBq Therapeutic range: MBq Iodine -131 [MBq] Can we predict the health risk and distinguish between stochastic and deterministic effects?

19 Why we can not? C ells w ith aberrations % Lymphocytes X-rays, neutrons Dose [Gy] Dose response curves for percentage of aberrant cells irradiated with various LET therapeutic sources of radiation is affected by decrease of cell survival. The saturation levels are independent on LET The saturation level depends on biochemico-physical conditions of cellular environment of individuals!

20 How looks inter-individuals variability in cytogenetic damage induced by low and high dose of radiation in the interphase?

21 MN Range:1,85-4,85 MBq MBq Again we can not predict response to high dose Cellular response in lymphocytes (MN frequency) from thyroid patients after diagnostic and therapeutic 131 I. A Cebulska-Wasilewska, J.Miszczyk, Z. Drag, J. K. Kim, (2011) Korean J.of. Rad.Industry,5,4,.

22 Range:1,85-4,85 MBq MBq Alteration of individual responses? SCE -biomarkers potentially associated to homologous recombination

23 Conclusions On average levels of molecular and cytogenetic damage after diagnostic dose of I-131 are lower than the level detected in control. A strong variability between subjects in a response to low (diagnostic) and high (therapeutic) dose of Iodine-131 is observed. Elevated levels of cytogenetic damage that are still observed 5 weeks after therapeutic treatment suggest a possible increase of secondary cancer risk. A lower and different for various subjects survival of cells after high dose of radiation may cause a suppression of detection of the cytogenetic damage at high dose region. In a consequence at high doses or exposures it might result in application s limitations of those biomarkers for both, health risk assessment and retrospective biological dosimetry.

24 A.Cebulska-Wasilewska, Z.Drąg M.Krzysiek A.Panek J.Miszczyk (FiSH in progress) A.Stępień R.Majewska MSc students: Barbara Filip Aanna Wójcik Jan Gąsiorkiewicz Konrad Tkocz Institute of Nuclear Physics Polish Academy of Sciences ul. Radzikowskiego 152, Kraków, Poland Jagiellonian University Chair of Epidemiology and Preventive Medicine Collegium Medicum of Jagiellonian University Nuclear Medicine Dpt, 5 th Military Polyclinic, Work performed within the strategic research project; - Technologies supporting the development of safe nuclear power from National Centre for Research and Development (NCBiR). - Research Task Development of methods to assure nuclear safety and radiation protection for current and future needs of nuclear power plants, No. SP/J/6/143339/11 - partly by: MN i SW 0296/B/P01/2008/35 and IAEA RC

25 Thank you for your attention

26 Human lymphocytes - X-rays 2.00 Human lymphocytes, MNBNC test, X-rays, Cytogenetic damage - micronuclei frequency (MNF) Mitotic Index NDI R NDI =.96 Frequency of micronuclei (x10 2 ) MNF(x) 1MN F(x) 2MN F(x) 3MN F(x) R MNtF(x) =.9 8 R 1M N F( x) =.9 9 R 2M N F( x) =.9 9 R 3M N F( x) =.9 7 P e r c e n t a g e o f d i v i d i n g c e l l s [ % ] Human lymphocytes, MNBNC test, X-rays, Dose [Gy] RDR Div C% R RD R =.98 R DivC% = Dose [Gy] Dos e [Gy] DR&EB standardizing dose response curves for MN and survival

27 Averge values of age of the investigated groups and mean values of mitotic index and dispersion from control s value, percentage of binucletaed cells detected and micronuclei frequency Group Age MI MIdisp. BNCF % MNF Control Low 131 I High 131 I ns ns ns.01

28 Mean values of biomarkers detected in investigated groups T-DNA RD T-DNA 0 SCE 2n SCE s disp HFC Control SD Low 131 I SD High 131 I SD Sig ns

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30 Biological markers, associated with environmentally induced genotoxic changes, are supposed to be useful tools for improving the prediction of risk to human health posed by exposure.