Telomeres are essential structures located at the ends of linear chromosomes in eukaryotes. In humans, they consist of short TTAGGG repeats and are associated with various proteins [ref]. They play a critical role in maintaining the structural integrity of chromosomes and regulating genome replication and stability. The shortening of telomeres is linked to cellular senescence and aging.

Telomeres have been shown to respond to various stressors associated with space travel. It has been observed that astronauts at the International Space Station (ISS) exhibited changes in telomere length during their missions and upon returning to Earth. However, the specific effectsof individual stressors, such as microgravity, ionizing radiation, and isolation, still need to be understood.

This study aimed to evaluate the effects of isolation and extravehicular activity (EVA) on telomere length during the AMADEE-24 Mars simulation.

Six analog astronauts (AAs) participated in the study. Blood samples were collected in K3EDTA tubes before the mission and on days 3, 8, 11, and 15 of isolation. Genomic DNA and total RNA were extracted using the Promega Maxwell RSC automated nucleic acid isolation workstation with corresponding kits. DNA was used to measure telomere length, while RNA was stored for further sequencing library preparation. Relative telomere length (RTL) was measured using quantitative real-time PCR, which determines the ratio of telomeric DNA to a single-copy gene for each sample. The RTL values before isolation were used as a baseline. Differences in RTL at the various time points were assessed using ANOVA with Tukey HSD post hoc tests.

Our results showed a near-significant shortening of telomeres in AAs’ leukocytes during the early days of isolation, compared to baseline. However, RTL began to increase at later time points, approaching baseline values. These findings suggest that the initial days of isolation may lead to immunosenescence and a temporary reduction in immune system activity, which then recoversto normal levels. This indicates that immune-modulating interventions could be beneficial during the early phases of isolation to maintain immune system activity and reduce potential health risks. We would like to thank AMADEE-2024 Analog Astronauts, Flight Planning, Remote Science Support, and GOST team members for their volunteering and support. Funding for the experiment was provided by the Institute of Molecular Biology of the National Academy of Sciences of Armenia.

Source: Gisane Khachatryan, Toma Sirunyan, Lilit Ghukasyan, Arpine Minasyan, Hovsep Ghazaryan, Andranik Chavushyan, Nina Gruber, Jelena Savic, Partha Dip Mahanta, Roksana Zakharyan, Arsen Arakelyan, “Telomere Length Dynamics in Analog Astronauts During the AMADEE-24 Mission”, AMADEE-24 Science Workshop Booklet 2024

“Genes4Mars” Project
Institute of Molecular Biology NAS RA, Yerevan, Armenia
Institute of Biomedicine and Pharmacy RAU, Yerevan, Armenia