Chromosome aberrations of clonal origin are present in astronauts’ blood lymphocytes

Abstract

Radiation-induced chromosome translocations remain in peripheral blood cells over many years, and can potentially be used to measure retrospective doses or prolonged low-dose rate exposures. However, several recent studies have indicated that some individuals possess clones of cells with balanced chromosome abnormalities, which can result in an overestimation of damage and, therefore, influence the accuracy of dose calculations. We carefully examined the patterns of chromosome damage found in the blood lymphocytes of twelve astronauts, and also applied statistical methods to screen for the presence of potential clones. Cells with clonal aberrations were identified in three of the twelve individuals. These clonal cells were present in samples collected both before and after space flight, and yields are higher than previously reported for healthy individuals in this age range (40–52 years of age). The frequency of clonal damage appears to be even greater in chromosomes prematurely condensed in interphase, when compared with equivalent analysis in metaphase cells. The individuals with clonal aberrations were followed-up over several months and the yields of all clones decreased during this period. Since clonal aberrations may be associated with increased risk of tumorigenesis, it is important to accurately identify cells containing clonal rearrangements for risk assessment as well as biodosimetry.

Assessment of Radiosensitivity and Biomonitoring of Exposure to Space Radiation

“…The use of cytogenetics assays to assess radiation effects in astronauts during spaceflight, have been applied since the late 1990's (Durante et al 2003;Fedorenko et al 2001;George et al 2004George et al , 2001Obe et al 1997;Testard et al 1996;Yang et al 1997). In general, these studies and more recent ones (Beaton-Green et al 2015;Cucinotta et al 2008;George et al 2010George et al , 2013 have shown that the number of chromosomal aberrations significantly increased during the mission, although there were large interindividual differences, which could not be attributed to the measured dose.…”

Malignancies Associated with Radiation in Aerospace Personnel-A Review of Evidence and Studies

“…Within 3 of 12 astronauts that took part, researchers found clonal aberrations in blood lymphocyte chromosomes [19]. Upon follow-up, such quantities of aberrations decreased.…”

Chromosome translocations and assessing human exposure to adverse environmental agents

“…These exposures have been associated with elevated translocation frequencies [Yong et al, 2009]. Astronauts are particularly vulnerable to increased radiation exposure, especially during space walks where even the minimally protective shielding provided by the space capsule is not available [Obe et al, 1997;George et al, 2004George et al, , 2005Cucinotta et al, 2008]. One of the impediments for longterm space flight is radiation exposure [Obe et al, 1999].…”