Isotopic Analysis of Calcium in Blood Plasma and Bone from Mouse Samples by Multiple Collector-ICP-Mass Spectrometry

Abstract

The biological processing of Ca produces significant stable isotope fractionation. The level of isotopic fractionation can provide key information about the variation in dietary consumption or Ca metabolism. To investigate this, we measured the 43 Ca/ 42 Ca and 44 Ca/ 42 Ca ratios for bone and blood plasma samples collected from mice of various ages using multiple collector-ICP-mass spectrometry (MC-ICP-MS). The 44 Ca/ 42 Ca ratio in bones was significantly (0.44 -0.84‰) lower than the corresponding ratios in the diet, suggesting that Ca was isotopically fractionated during Ca metabolism for bone formation. The resulting 44 Ca/ 42 Ca ratios for blood plasma showed almost identical, or slightly higher, values (0.03 -0.2‰) than found in a corresponding diet. This indicates that a significant amount of Ca in the blood plasma was from dietary sources. Unlike that discovered for Fe, there were no significant differences in the measured 44 Ca/ 42 Ca ratios between female and male specimens (for either bone or blood plasma samples). Similarity, the 44 Ca/ 42 Ca ratios suggests that there were no significant differences in Ca dietary consumption or Ca metabolism between female and male specimens. In contrast, the 44 Ca/ 42Ca ratios of blood plasma from mother mice during the lactation period were significantly higher than those for all other adult specimens. This suggests that Ca supplied to infants through lactation was isotopically lighter, and the preferential supply of isotopically lighter Ca resulted in isotopically heavier Ca in blood plasma of mother mice during the lactation period. The data obtained here clearly demonstrate that the Ca isotopic ratio has a potential to become a new tool for evaluating changes in dietary consumption, or Ca metabolism of animals. both of these two isotope tracer approaches are based on the assumption that the spiked isotope replaces the native element, and behaves in an identical manner. 1This indicates that mimicing of the isotopes to the native nutrients must be considered in order to obtain reliable data for elemental metabolism. Faced with this problem, we have developed a new isotope tracer technique based on changes in the isotopic composition of Ca due to a mass-dependent isotopic effect. Hence, no spiking with additional elements, such as radio isotopes or enriched isotopes, was required, and therefore, no mimicing to the native nutrients is required. Moreover, it should be noted that the present stable isotope approach allows regular monitoring of the nutritional status of Ca of the donor without any spiking or addition of isotopes. The measurement of stable isotopes of nitrogen ( 15 N/ 14 N) and carbon ( 13 C/ 12 C) is a useful tool to trace trophic relationships and food webs. 3,12,13 This method assumes that, during the assimilation process, there is an enrichment in heavy isotopes (i.e., 13 C or 15 N) compared to the dietary intake, which is compensated by the preferential excretion of lighter isotopes. 14,15 The isotopic composition of an animals' tissue reflec...

Assessing human weaning practices with calcium isotopes in tooth enamel

“…*Described in ref. 59. including horses, seals, mice, deer, sheep, and Göttingen minipigs (30,(42)(43)(44)(45) and is assumed to be comparable in humans (46,47). The average δ 44/42 Ca value of wisdom tooth enamel that we measured in nine adult individuals (−1.58 ± 0.26 ‰, 2 SD, n = 9) is thus in good agreement with a hypothetical average Western diet composition of −1.00‰.…”

Calcium isotope ratios in animal and human bone

“…Samples were then dissolved in 2 M quartz-distilled HCl. All column chemistry was done in a class 1000 clean Skulan and DePaolo (1999)), and 2 standard deviations of the mean for the deer (n = 3, Chu et al (2006)) and mouse (n = 4, Hirata et al (2008)) data. laboratory, with quartz-distilled acids.…”

“…These range from studies of rocks, rivers, soils, and vegetation in terrestrial samples (Skulan et al, 1997;Schmitt et al, 2003;Chu et al, 2006;Tipper et al, 2006;Tipper et al, 2008;Jacobson and Holmden, 2008;Ewing et al, 2008;Page et al, 2008;Amini et al, 2009;Cenki-Tok et al, 2009) to marine biogenic and inorganic precipitates (Zhu and Macdougall, 1998;Nägler et al, 2000;Marriott et al, 2004;DePaolo, 2005, 2007;Sime et al, 2005Sime et al, , 2007Farkaš et al, 2007a,b;Kasemann et al, 2008;Griffith et al, 2008;Teichert et al, 2009), and other biological materials such as animal soft tissues (Skulan and DePaolo, 1999;Skulan et al, 2007;Hirata et al, 2008) and bone apatite (Skulan et al, 1997;Skulan and DePaolo, 1999;Clementz et al, 2003;Chu et al, 2006;Reynard et al, 2008a;Heuser and Eisenhauer, 2008;Heuser et al, 2009).…”

“…Measurements of d 44/42 Ca of diet, soft tissues, and bone have helped clarify calcium isotopic fractionation in a few animals (Skulan and DePaolo, 1999;Chu et al, 2006;Hirata et al, 2008); the data are plotted in Fig. 1.…”

Comments on “Application of laser ablation multicollector inductively coupled plasma mass spectrometry for the measurement of calcium and lead isotope ratios in packaging for discriminatory purposes”

“…6 in Wieser et al, [4] Fig. 2 in Schmitt et al, [5] Table 2 in Chu et al, [6] and Table 2 in Hirata et al [7] ). Hence, the lack of correlation between Ca in Fig.…”