Assessing Telomere Lengths and Telomerase Activity in Astronauts (Telomeres) - 09.20.17

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Telomeres are "caps" on the ends of chromosomes that protect them from fraying, much like the end of a shoelace, and an enzyme, called telomerase, maintains their length. Telomeres shorten over time, and the rate at which this occurs can be increased by stress, leading to accelerated aging, cardiovascular disease, cancer, and an impaired immune system. The Telomeres investigation collects crew member blood samples to determine how telomeres and telomerase are affected by space travel.
Science Results for Everyone
Information Pending

The following content was provided by Susan Bailey, Ph.D., and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom: Telomeres

Principal Investigator(s)
Susan Bailey, Ph.D., Colorado State University, Fort Collins, CO, United States

Information Pending

NASA Johnson Space Center, Human Research Program, Houston, TX, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
NASA Research Office - Human Research Program (NASA Research-HRP)

Research Benefits
Earth Benefits, Scientific Discovery, Space Exploration

ISS Expedition Duration
March 2015 - March 2016; March 2016 - September 2017

Expeditions Assigned

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • This research is needed to establish how the combined stresses of long-duration spaceflight influence telomere shortening and changes in telomerase activity in blood samples from crew members collected pre-, in-, and post-flight.
  • This research is needed in order to better evaluate the impact of future space flight, specifically in regard to changes in telomere length and telomerase activity, which have the potential to contribute to accelerated aging, reduced immune function, cardiovascular disease, and cancer.

Standard assays are performed on blood samples to assess crew members’ telomere lengths and telomerase activity as part of their spaceflight biochemical profiles pre-flight (to establish baseline), during flight (to evaluate short-term/temporary changes), and post-flight (to evaluate long-term/permanent changes). Together with investigation of potential mechanisms and mitigation strategies, as well as information related to diet/nutrition, radiation exposure, gender, age, stress, genetic predisposition/sensitivity, and appropriate statistical analyses, results from this experiment can help researchers to establish relevant relationships and suggest potential interventions (e.g., antioxidants) for further study. The Longitudinal Study of Astronaut Health, an electronic database of medical information collected over the active and post-career lives of the astronauts, will be a valuable resource in this regard. The proposed studies are also strongly grounded to on-going, as well as previous, biodosimetry studies utilizing chromosome aberration data. For example, samples for cytogenetic analysis from about 30 ISS astronauts have been archived, and can now be utilized (built upon) for telomere analyses.

The overall goal of this project is to characterize and begin to define the risk (and possible underlying mechanisms) of accelerated telomere shortening and changes in telomerase activity associated with spaceflight, a lifestyle with a variety of unique stressors. Consequences of accelerated telomere shortening would include advanced aging and age-associated phenotypes, ranging from reduced immune function, effects of which could be immediate/short-term and so influence performance during a mission, to cardiovascular disease and cancer, representing more long-term/permanent outcomes.

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Space Applications
Long-duration spaceflight takes a toll on the body. This includes increases in physical and emotional stresses that can impact crew health. Inadequate nutrition, disrupted sleep, and microgravity itself contribute to crew stress, which in turn can contribute to shortened telomeres. Radiation exposure can also shorten telomeres. This investigation identifies the spaceflight-related risks of accelerated telomere shortening and altered telomerase activity, which can have both short-term and long-term effects. Telomere degeneration could cause reduced immune function, which could have immediate effects on crew health, or it could cause cardiovascular disease and cancer years later. Telomere maintenance is an important biomarker for space travelers dealing with inadequate nutrition, radiation exposure, and physical and psychological stress.

Earth Applications
Stress can have dramatic effects on human health. Results from the Telomeres investigation are expected to improve understanding of how life stresses can influence telomere maintenance, which in turn is related to aging and age-related diseases. Establishing relationships between stress and shortened telomeres, including altered telomerase activity, could lead to potential countermeasures for reduced immune function, cardiovascular disease, and cancer.

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Operational Requirements and Protocols

A minimum of 10 flight subjects (and 10 age-matched ground control subjects) are required for this investigation. Additionally, data is collected from the one-year mission US crew member and his ground-based twin as part of the Twins Study.
For 6-month missions, in-flight ambient blood collections are planned on approximately flight day 90 (as close to mid-mission as possible) and R-1 for a subset of subjects. For the 1-year mission, inflight collections are planned on approximately FD45 and FD233 as part of the Twins Study. Sessions must be aligned with a returning Soyuz vehicle for ambient sample return.

Sixteen (16) mL of blood are collected from the subject during each inflight session. Blood samples are returned at ambient temperature to the ground (JSC) for processing within 72 hours of collection.  Information (via data share) from a Food Frequency Questionnaire completed by the crewmember is also obtained, in order to make correlations between astronaut health in relation to nutritional status and changes in telomere length and telomerase activity. Information (via data share) will also be obtained for radiation exposures (dosimetry).

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Decadal Survey Recommendations

Animal and Human Biology AH13
Animal and Human Biology AH16

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Results/More Information

Information Pending

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Related Websites

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image Telomere length will be evaluated according to established protocols, including quantitative (Q)-FISH (30). Below are representative microscopic images of a human metaphase chromosome spread hybridized with a peptide nucleic acid (PNA) probe complementary to the telomere sequence and labeled with a red fluorophore (left), and the corresponding karyotype of the metaphase (right). Q-FISH analysis provides relative telomere length measurements based on fluorescence intensities for each chromosome.
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image TELI-FISH. 3D reconstruction of telomere fluorescence in situ hybridization combined with immunostaining (e.g., stem cell markers) for measurement of telomere fluorescence/lengths in specific cell compartments.
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