Salivary Markers of Metabolic Changes during Space Missions (Check-Saliva) - 07.14.16
Salivary Markers of Metabolic Changes during Space Missions (Check-Saliva) tests crewmembers' saliva, blood, and urine before, during and after spaceflight to study whether saliva tests can serve as reliable health monitors. Long-term exposure to the microgravity environment results in reduced bone and muscle mass, which is related to changes in certain substances in the bloodstream and urine. Some of these changes can also be detected in saliva samples, so tests using Check-Saliva can validate whether saliva and/or urine can be used as simple, non-invasive tools to monitor crewmembers' bone and muscle status during a space mission. Science Results for Everyone
Information Pending Experiment Details
OpNom: Bone/Muscle Check
Massimo Cirillo, MD, Dept. of Medicine & Surgery (Nephrology), Italy
Giancarlo Bilancio, M.D, Salerno University, Italy
Salerno University, Salerno, Italy
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Italian Space Agency (ASI)
Earth Benefits, Space Exploration
ISS Expedition Duration
September 2014 - September 2015
- The reduction in bone/muscle mass secondary to microgravity exposure is a limiting step in the duration of space missions. The monitoring of the biochemical aspects of this reduction depends at present on the collection of blood and/or urine samples. The definition of other simple tools for monitoring the bone/muscle status could be of help in detection, treatment and control of the microgravity-induced reduction in bone/muscle mass.
The investigation aims to perform the following procedures:
- In the days preceding the space mission: measurements of bone/muscle mass together with collection of samples of saliva, blood, and urine;
- At different time-points during space mission: collection of samples of saliva and urine;
- At the completion of the space mission: measurements of bone/muscle mass together with collection of samples of saliva, blood, and urine.
- Samples of saliva, blood, and urine shall be frozen as rapidly as possible, and later analyzed for measurements of substances which reflect the bone/muscle metabolism.
The investigation will provide information on the reliability of saliva and urine as a simple and non-invasive tool to monitor changes in bone/muscle status during space mission. This information could be the first step in the development of space-designed devices for rapid measurements of markers of bone/muscle status. Theoretically, the use of saliva as marker of the blood composition could be of use in other microgravity-induced disorders, as well as in medicine on Earth.
A number of previous observations show that exposure to microgravity results in a reduction of bone and muscle mass. These effects are a limiting step in the duration of space mission. Similar effects on bone and muscle mass are induced by prolonged bed-rest, that is, by the experimental condition which is used to simulate microgravity on Earth. The reduction in bone and muscle mass is associated with changes in blood levels and, secondarily, in urine levels, of several substances, which are used in research and clinical practice, as markers of bone or muscle metabolism. A recent program of the Italian Space Agency (ASI) included a set of bed-rest experiments which confirmed and extended these previous observations.
Saliva and urine are biological fluids which can be easily and repeatedly collected without risks. Past and recent data from different laboratories consistently indicate that the chemical composition of saliva and urine reflects, in many aspects, the chemical composition of blood. This is true also for some markers of bone or muscle conditions. In fact, saliva, urine, and blood tend to have similar levels of bone mineral components (calcium and phosphate), of bone-related vitamins (vitamin D), and of end-products of muscle protein (urea), etc.
Blood-based measurements are effective, but saliva-based detection of metabolic changes would be simpler and less invasive for use in spaceflight. If the results support testing saliva for the presence of biological markers, future automated devices could rapidly test saliva instead of blood samples before, during and after space missions.
If saliva can be used as a reliable indicator of bone and muscle health, it may also be used as a simple, automated, non-invasive clinical tool on Earth. Salivary markers could be used to test for certain medical conditions in settings where blood samples are difficult or impossible, including in remote areas, for young children, or for large-scale screening of a general population.
Operational Requirements and Protocols
The measurements of bone/muscle mass, and the collection of biological samples, require standardized conditions: a 20 min rest (still sit) for bone/muscle measurements, and 3-4 hours of fasting after morning breakfast for the collection biological samples. The protocol on Earth mirrors the protocol on ISS.
- Pre-flight procedures are performed by the PI group in the days preceding the space mission and will include: measurements of bone/muscle mass by pQCT together with the collection of samples of saliva, blood, and urine.
- In-flight procedures should be performed by crewmembers at different time-points during space mission and will include: collection of samples of saliva and urine samples; labeling, freezing, and storage of the samples. The participating crewmembers are asked to collect samples of saliva at three, or more, separate time points. The research focuses on saliva and, secondarily, on urine. Urinary samples are used to verify the presence/absence at given time points of the expected changes in urinary markers of bone and muscle metabolism.
- Post-flight procedures are performed by the PI group at completion of the space mission and mirror Pre-flight procedures (measurements of bone/muscle mass by pQCT together with collection of samples of saliva, blood, and urine).
Decadal Survey Recommendations
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