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Use of Potassium Citrate to Reduce the Risk of Renal Stone Formation During SpaceflightIntroduction: NASA s Vision for Space Exploration centers on exploration class missions including the goals of returning to the moon and landing on Mars. One of NASA s objectives is to focus research on astronaut health and the development of countermeasures that will protect crewmembers during long duration voyages. Exposure to microgravity affects human physiology and results in changes in the urinary chemical composition favoring urinary supersaturation and an increased risk of stone formation. Nephrolithiasis is a multifactorial disease and development of a renal stone is significantly influenced by both dietary and environmental factors. Previous results from long duration Mir and short duration Shuttle missions have shown decreased urine volume, pH, and citrate levels and increased calcium. Citrate, an important inhibitor of calcium-containing stones, binds with urinary calcium reducing the amount of calcium available to form stones. Citrate inhibits renal stone recurrence by preventing crystal growth, aggregation, and nucleation and is one of the most common therapeutic agents used to prevent stone formation. Methods: Thirty long duration crewmembers (29 male, 1 female) participated in this study. 24-hour urines were collected and dietary monitoring was performed pre, in, and postflight. Crewmembers in the treatment group received two potassium citrate (KCIT) pills, 10 mEq/pill, ingested daily beginning 3 days before launch, all inflight days and through 14 days postflight. Urinary biochemical and dietary analyses were completed. Results: KCIT treated subjects exhibited decreased urinary calcium excretion and maintained the levels of calcium oxalate supersaturation risk at their preflight levels. The increased urinary pH levels in these subjects reduced the risk of uric acid stones. Discussion: The current study investigated the use of potassium citrate as a countermeasure to minimize the risk of stone formation during ISS missions. Results suggest that supplementation with potassium citrate decreases the risk of stone formation during and immediately after spaceflight.
Document ID
20080046171
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Whitson, P. A.
(NASA Johnson Space Center Houston, TX, United States)
Pietrzyk, R. A.
(Wyle Integrated Science and Engineering Group Houston, TX, United States)
Sams, C. F.
(NASA Johnson Space Center Houston, TX, United States)
Jones, J. A.
(NASA Johnson Space Center Houston, TX, United States)
Nelman-Gonzalez, M.
(Wyle Integrated Science and Engineering Group Houston, TX, United States)
Hudson, E. K.
(JES Tech Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2008
Subject Category
Aerospace Medicine
Meeting Information
Meeting: 80th Annual Meeting of the Aerospace Medical Medical Association
Location: Los Angeles, CA
Country: United States
Start Date: May 3, 2009
End Date: May 7, 2009
Distribution Limits
Public
Copyright
Other

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