Cytogenetic damage in the blood lymphocytes of astronauts: Effects of repeat long-duration space missions

Abstract

Human missions onboard the International Space Station (ISS) are increasing in duration and several astronauts have now participated in second ISS increments. The radiation environment in space is very different from terrestrial radiation exposure and it is still unclear if space flight effects and radiation from repeat missions are simply additive, which potentially confounds the assessment of the cumulative risk of radiation exposure. It has been shown that single space missions of a few months or more on the ISS can induce measureable increases in the yield of chromosome damage in the blood lymphocytes of astronauts, and it appears that cytogenetic biodosimetry can be used reliably to estimate equivalent dose and radiation risk. We have now obtained direct in vivo measurements of chromosome damage in blood lymphocytes of five astronauts before and after their first and second long duration space flights. Chromosome damage was assessed by fluorescence in situ hybridization technique using three different chromosome painting probes. All astronauts showed an increase in total exchanges and translocations after both the first and second flight. Biological dose measured using either individual assessment or a population assessment supports an additive risk model.

Characterization of Aspergillus fumigatus Isolates from Air and Surfaces of the International Space Station

“…Figure S1 in the supplemental material shows the same phylogenic data represented in a phylogram. As it has been suggested previously that genetic consequences resulting from irradiation exposure during time in space may manifest as insertions and deletions (indels) over point mutations (28–30), we analyzed ISSFT-021, IF1SW-F4, and CEA10 and averages from all sequenced isolates included in this study against the reference genome (Af293) and found no obvious enrichment for indels in the ISS isolates (see Fig. S2 in the supplemental material).…”

“…S2 in the supplemental material), suggesting that life aboard the space station was not accompanied by an accumulation of mutations presumably from enhanced exposure to irradiation and microgravity; however, since the proper terrestrial control strains do not exist for ISSFT-021 and IF1SW-F4, we cannot determine/quantify mutations that may have accumulated during time aboard the ISS. Interestingly, previous data suggest that DNA damage resulting from time aboard the ISS may favor chromosomal aberrations and large deletions over point mutations (28–30), a conclusion that may have been fueled by studies that reported finding no detectable mutations from time in space, although these experiments utilized experimental setups that would favor detection of point mutations over large genetic lesions, or the studies were possibly too short in duration for mutations to accumulate (44). Sequence analysis with ISS A. fumigatus strains suggested that there is no enrichment for any type of mutation we could identify through our resequencing-based mapping approach, namely, indels, in comparison with Af293 (see Fig.…”

Induction of Chromosomal Aberrations at Fluences of Less Than One HZE Particle per Cell Nucleus

“…This argument suggests an approximate doubling of the bystander contribution of 1.1 per 100 cells due to fractionation, which leads to an estimate of ;2.7 aberrations per 100 cells and is consistent with the increase observed in the 30 min to Our results for human lymphocytes at low doses do not provide evidence for NTE contributing to the induction of chromosomal aberrations. Chromosomal aberrations are used to monitor astronauts' radiation exposures while on the International Space Station (33,34), and our lack of a bystander effect in lymphocytes provides support for the accuracy of this assay. This could be due to the fact that in contrast to irradiation of confluent fibroblasts, lymphocytes irradiated in blood tubes have reduced modes of intercellular effects compared to fibroblasts.…”

Space Radiation Risks for Astronauts on Multiple International Space Station Missions

“…Other factors to be considered include smoking history which effects lung, esophagus, oral cavity, bladder and several other cancers, and reproductive history which can impact the risk of breast and other cancers in women [29]. The collection of biodosimetry and biomarker data prior to flight and at multiple time points over several years post-flight [47] would aid in understanding of causation, especially for repeat ISS flyers.…”