A pilot study on the use of natural calcium isotope (44Ca/40Ca) fractionation in urine as a proxy for the human body calcium balance

Heuser, Alexander; Eisenhauer, Anton

doi:10.1016/j.bone.2009.11.037

Cited by 86 publications

(98 citation statements)

References 27 publications

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“…This model uses the difference in Ca isotopic composition of urine before and during bed rest to estimate the rate of bone loss. It is similar to the model by Heuser and Eisenhauer (6) in that it explicitly includes renal Ca isotope fractionation. We have also extended the model to explicitly include hepatic Ca isotope fractionation.…”

Section: Datamentioning

confidence: 95%

“…Because δ 44/42 Ca is directly related to net BMB, it should be possible to use Ca isotopes to quantitatively assess the extent of bone loss (or gain). To illustrate this potential, we used an updated isotope mass balance model based on models developed in the works by Skulan and DePaolo (4) and Heuser and Eisenhauer (6). The model quantifying the amount of bone lost during the 30-d bed rest study is depicted in Fig.…”

Section: Datamentioning

confidence: 99%

“…ε 44/42 Ca urine . Renal Ca isotope fractionation is an important but poorly constrained term (6). Soft tissue tend to have a Ca isotopic composition similar to the composition of diet, whereas urine tends to be isotopically heavy (4,6,8).…”

Section: Datamentioning

confidence: 99%

“…Comparison of Ca in urine and soft tissue indicates that heavy isotopes are preferentially excreted (6). Although the mechanism of this renal Ca isotope effect is not well understood, Ca isotope abundances in soft tissue should shift to heavier Ca isotope values when BMB is positive and Ca excretion rate decreases and lighter values when BMB is negative and Ca excretion rate increases (see Discussion).…”

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confidence: 98%

“…Urine samples were given priority over blood; higher Ca concentrations in urine compared with blood ease analytical challenges, and urine samples are easier to obtain from subjects. This number of sample analyses is not practical with the time-consuming mass spectrometric methods used in previous studies (6)(7)(8). Therefore, we applied a validated method that uses multicollector inductively coupled plasma source mass spectrometry (9).…”

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confidence: 99%

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Rapidly assessing changes in bone mineral balance using natural stable calcium isotopes

Morgan

Skulan

Gordon

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

119

104

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The ability to rapidly detect changes in bone mineral balance (BMB) would be of great value in the early diagnosis and evaluation of therapies for metabolic bone diseases such as osteoporosis and some cancers. However, measurements of BMB are hampered by difficulties with using biochemical markers to quantify the relative rates of bone resorption and formation and the need to wait months to years for altered BMB to produce changes in bone mineral density large enough to resolve by X-ray densitometry. We show here that, in humans, the natural abundances of Ca isotopes in urine change rapidly in response to changes in BMB. In a bed rest experiment, use of high-precision isotope ratio MS allowed the onset of bone loss to be detected in Ca isotope data after about 1 wk, long before bone mineral density has changed enough to be detectable with densitometry. The physiological basis of the relationship between Ca isotopes and BMB is sufficiently understood to allow quantitative translation of changes in Ca isotope abundances to changes in bone mineral density using a simple model. The rate of change of bone mineral density inferred from Ca isotopes is consistent with the rate observed by densitometry in long-term bed rest studies. Ca isotopic analysis provides a powerful way to monitor bone loss, potentially making it possible to diagnose metabolic bone disease and track the impact of treatments more effectively than is currently possible.osteopenia | biomarker | medical geology | biosignature | spaceflight

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Section: Datamentioning

confidence: 95%

Section: Datamentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

mentioning

confidence: 98%

mentioning

confidence: 99%

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Rapidly assessing changes in bone mineral balance using natural stable calcium isotopes

Morgan

Skulan

Gordon

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

119

104

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Calcium Isotopic Compositions of Normal Mid‐Ocean Ridge Basalts From the Southern Juan de Fuca Ridge

Zhu

Liu

et al. 2018

JGR Solid Earth

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Mantle peridotites show that Ca is isotopically heterogeneous in Earth's mantle, but the mechanism for such heterogeneity remains obscure. To investigate the effect of partial melting on Ca isotopic fractionation and the mechanism for Ca isotopic heterogeneity in the mantle, we report high‐precision Ca isotopic compositions of the normal Mid‐Ocean Ridge Basalts (N‐MORB) from the southern Juan de Fuca Ridge. δ44/40Ca of these N‐MORB samples display a small variation ranging from 0.75 ± 0.05 to 0.86 ± 0.03‰ (relative to NIST SRM 915a, a standard reference material produced by the National Institute of Standards and Technology), which are slightly lower than the estimated Upper Mantle value of 1.05 ± 0.04‰ and the Bulk Silicate Earth (BSE) value of 0.94 ± 0.05‰. This phenomenon cannot be explained by fractional crystallization, because olivine and orthopyroxene fractional crystallization has limited influence on δ44/40Ca of N‐MORB due to their low CaO contents, while plagioclase fractional crystallization cannot lead to light Ca isotopic compositions of the residue magma. Instead, the lower δ44/40Ca of N‐MORB samples compared to their mantle source is most likely caused by partial melting. The offset in δ44/40Ca between N‐MORB and BSE indicates that at least 0.1–0.2‰ fractionation would occur during partial melting and light Ca isotopes are preferred to be enriched in magma melt, which is in accordance with the fact that δ44/40Ca of melt‐depleted peridotites are higher than fertile peridotites in literature. Therefore, partial melting is an important process that can decrease δ44/40Ca in basalts and induce Ca isotopic heterogeneity in Earth's mantle.

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The Use of Stable Isotope Techniques for Studying Mineral and Trace Element Metabolism in Humans

Walczyk

2012

Isotopic Analysis

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A pilot study on the use of natural calcium isotope (44Ca/40Ca) fractionation in urine as a proxy for the human body calcium balance

Cited by 86 publications

References 27 publications

Rapidly assessing changes in bone mineral balance using natural stable calcium isotopes

Rapidly assessing changes in bone mineral balance using natural stable calcium isotopes

Calcium Isotopic Compositions of Normal Mid‐Ocean Ridge Basalts From the Southern Juan de Fuca Ridge

The Use of Stable Isotope Techniques for Studying Mineral and Trace Element Metabolism in Humans

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