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Rapidly Assessing Changes in Bone Mineral Balance Using Natural Stable Calcium IsotopesWe demonstrate that variations in the Ca isotope ratios in urine rapidly and quantitatively reflect changes in bone mineral balance. This variation occurs because bone formation depletes soft tissue of light Ca isotopes, while bone resorption releases that isotopically light Ca back into soft tissue. In a study of 12 individuals confined to bed rest, a condition known to induce bone resorption, we show that Ca isotope ratios shift in a direction consistent with net bone loss after just 7 days, long before detectible changes in bone density occur. Consistent with this interpretation, the Ca isotope variations track changes observed in N-teleopeptide, a bone resorption biomarker, while bone-specific alkaline phosphatase, a bone formation biomarker, is unchanged. Ca isotopes can in principle be used to quantify net changes in bone mass. Ca isotopes indicate an average loss of 0.62 +/- 0.16 % in bone mass over the course of this 30-day study. The Ca isotope technique should accelerate the pace of discovery of new treatments for bone disease and provide novel insights into the dynamics of bone metabolism.
Document ID
Document Type
Preprint (Draft being sent to journal)
Morgan, J. L. L. (Arizona State Univ. Tempe, AZ, United States)
Gordon, G. W. (Arizona State Univ. Tempe, AZ, United States)
Romaniello, S. J. (Arizona State Univ. Tempe, AZ, United States)
Skulan, J. L. (Geology Museum Madison, WI, United States)
Smith, S. M. (NASA Johnson Space Center Houston, TX, United States)
Anbar, A. D. (Arizona State Univ. Tempe, AZ, United States)
Date Acquired
August 25, 2013
Publication Date
January 1, 2011
Subject Category
Aerospace Medicine
Report/Patent Number
Meeting Information
Goldschmidt Conference(Prague)
Distribution Limits
Public Use Permitted.

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NameType 20110011198.pdf STI