title: Telomere Length in Aged Mayak PA Nuclear Workers Chronically Exposed to Internal Alpha and External Gamma Radiation.
abstract: Telomeres consist of GC-rich DNA repeats and the "shelterin" protein complex that together protect chromosome ends from fusion and degradation. Telomeres shorten with age due to incomplete end replication and upon exposure to environmental and intrinsic stressors. Exposure to ionizing radiation is known to modulate telomere length. However, the response of telomere length in humans chronically exposed to radiation is poorly understood. Here, we studied relative telomere length (RTL) by IQ-FISH to leukocyte nuclei in a group of 100 workers from the plutonium production facility at the Mayak Production Association (PA) who were chronically exposed to alpha-emitting ((239)Pu) radiation and/or gamma (photon) radiation, and 51 local residents serving as controls, with a similar mean age of about 80 years. We applied generalized linear statistical models adjusted for age at biosampling and the second exposure type on a linear scale and observed an age-dependent telomere length reduction. In those individuals with the lowest exposure, a significant reduction of about 20% RTL was observed, both for external gamma radiation (≤1 Gy) and internal alpha radiation (≤0.05-0.1 Gy to the red bone marrow). In highly exposed individuals (>0.1 Gy alpha, 1-1.5 Gy gamma), the RTL was similar to control. Stratification by gender revealed a significant (∼30%) telomere reduction in low-dose-exposed males, which was absent in females. While the gender differences in RTL may reflect different working conditions, lifestyle and/or telomere biology, absence of a dose response in the highly exposed individuals may reflect selection against cells with short telomeres or induction of telomere-protective effects. Our observations suggest that chronic systemic exposure to radiation leads to variable dose-dependent effects on telomere length.
authors.affiliation: a   Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, D-80937 Munich, Germany; and.
authors.forename: Harry
authors.initials: H
authors.lastname: Scherthan
authors.affiliation: b   Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region, 456780 Russian Federation.
authors.forename: Natalia
authors.initials: N
authors.lastname: Sotnik
authors.affiliation: a   Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, D-80937 Munich, Germany; and.
authors.forename: Michel
authors.initials: M
authors.lastname: Peper
authors.affiliation: a   Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, D-80937 Munich, Germany; and.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Schrock
authors.affiliation: b   Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region, 456780 Russian Federation.
authors.forename: Tamara
authors.initials: T
authors.lastname: Azizova
authors.affiliation: a   Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, D-80937 Munich, Germany; and.
authors.forename: Michael
authors.initials: M
authors.lastname: Abend
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics; D000512:Alpha Particles / Q000009:adverse effects*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009688:Nuclear Reactors; D016273:Occupational Exposure / Q000009:adverse effects*; D012426:Russia; D016615:Telomere / Q000235:genetics* / Q000528:radiation effects*; D013997:Time Factors