Defining the Relation Between Biomarkers of Oxidative and Inflammatory Stress and Atherosclerosis Risk in Astronauts During and After Long-duration Spaceflight (Cardio Ox) - 12.03.13
Science Objectives for Everyone
Future human space travel missions may increase the risk of oxidative and inflammatory damage primarily from radiation, but also from psychological stress, reduced physical activity, diminished nutritional standards and exposure to elevated oxygen levels during extravehicular activity. There is evidence that higher levels of oxidative and inflammatory stress and associated damage to blood vessels contribute to cardiovascular disease. The purpose of this study is to measure levels of biomarkers in blood and urine that are affected by oxidative and inflammatory stress before, during, and after long duration spaceflight and relate them to the risk of developing atherosclerosis.
Science Results for Everyone
OpNom: Cardio OxPrincipal Investigator(s)
Johnson Space Center, Human Research Program, Houston, TX, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)Research Benefits
Scientific Discovery, Earth Benefits, Space ExplorationISS Expedition Duration:
September 2013 - September 2014Expeditions Assigned
37/38,39/40,41/42,43/44Previous ISS Missions
- Future human space travel will primarily consist of long duration missions onboard the International Space Station or exploration class missions to Mars, its moons, or nearby asteroids. These types of missions may increase the risk of increased oxidative damage and inflammation primarily from radiation, but also from psychological stress, reduced physical activity, diminished nutritional standards and, in the case of extravehicular activity, increased oxygen exposure. There is evidence that increased oxidative damage and inflammation can accelerate the development of atherosclerosis. This study will inform Space Medicine about the potential long-term effects of space flight (5 yrs post-landing) on cardiovascular health.
The investigation intends to provide a greater understanding of space-related cardiovascular disease risk, specifically to identify and validate markers and indices of increased cardiovascular health risk during and after long-duration spaceflight.
- The experiment is designed to determine whether markers of oxidative stress and inflammation in the blood and urine are elevated in astronauts participating in long-duration space flight and whether there are concomitant changes in arterial structure and function. Specifically, this study seeks to clarify the previously conflicting observations regarding oxidative stress and inflammation during and after space flight and relate these to long-term changes in vascular structure and function which might predict future development of atherosclerosis in astronauts.
Future human space travel will primarily consist of long duration missions onboard the International Space Station or exploration class missions to Mars, its moons, or nearby asteroids. These types of missions may increase the risk of oxidative and inflammatory damage primarily from radiation, but also from psychological stress, reduced physical activity, diminished nutritional standards and, in the case of extravehicular activity, hyperoxic/hypoxic exposure. There is evidence that increased oxidative damage and inflammation can accelerate the development of atherosclerosis. The purpose of this study is to identify biomarkers of oxidative stress and inflammation before, during, and after long duration spaceflight and to relate them to indices of atherosclerosis risk. The investigators will measure a number of blood and urine biomarkers, some of which we have previously shown to be elevated with spaceflight. Furthermore, they will track arterial structure and function via ultrasound measures of carotid intima-medial thickness and brachial artery flow-mediated dilation. Carotid intima-medial thickness has been shown to be a better indicator than Framingham Risk scores for prediction of atherosclerosis. Brachial flow-mediated dilation is a good index of endothelium-dependent vasodilation, which is a sensitive predictor of atherosclerotic risk. The investigators hypothesize that these biomarkers of oxidative and inflammatory stress will be increased with spaceflight and will correlate with decreased flow-mediated dilation and increased carotid intima-medial thickness. Furthermore, they hypothesize that measures of oxidative stress will return to baseline after flight, but that biomarkers of inflammatory stress and vascular indices of atherosclerosis risk will remain elevated. This is the first study to propose assessing atherosclerotic risk using biochemical, structural and functional measures during, immediately after, and for up to five years after landing.
The primary objectives of this study are to elucidate whether biomarkers of oxidative and inflammatory stress are elevated during and after space flight and to determine whether these are associated with an increased risk for the development of atherosclerosis and other cardiovascular diseases. This study is unique in its approach to evaluate the long-term health consequences of space flight, which may be important in the care of astronauts during and after their careers at NASA. Thus, while providing important information about the short-term effects of space flight, we also will investigate potential consequences of this unique occupational environment. These data will serve as the basis for future assessments of countermeasures and the safety of space exploration beyond low Earth orbit.Earth Applications
This study proposes to investigate, for the first time, the risk for cardiovascular disease in astronauts, a unique population who as part of their occupation are knowingly exposed to a number of conditions that will likely increase their risk for cardiovascular diseases. It is believed that an imbalance between anti- and pro-oxidative substances contributes to many of the initial changes associated with atherosclerotic vascular disease. Few studies have been designed to prospectively examine both the immediate and long-term effects in similar high-risk groups. Unlike the results from traditional cross-sectional study designs that are limited to interpretation due to certain assumptions, the findings from this study will overcome such deficiencies and are likely to provide researchers and clinicians with insights into the development and progression of atherosclerosis in this unique subject population.
A total of twelve subjects are required for this investigation. In-flight sessions are planned on flight day 15 (FD15), FD60 and FD180/R-15; each session includes an ultrasound scan, blood and 24-hour urine sample collection. For each session, the blood sample is taken within 24 hours of the start of urine collection and scans are performed within 3 days of the blood collection. Scheduling tolerance for the FD15 session is ±5 days; all other sessions are ±7 days. Subjects will perform self-scans using Remote Guidance, therefore, real-time video downlink is required. Blood and urine samples are returned to Earth for analysis, ideally within a year of the sampling date.Operational Protocols
Inflight ultrasound scans using the HRF Ultrasound 2 are performed on FD15, 30 and 180/R-15 via real-time Remote Guidance. Each scan is preceded or followed by blood and 24-hour urine sample collections. The blood samples are processed in the refrigerated centrifuge and then stored in the MELFI. Urine is collected void by void for 24 hours and syringe aliquot samples are stored in the MELFI.