| 1. |
- Murphy, Michelle M, et al.
(författare)
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Longitudinal study of the effect of pregnancy on maternal and fetal cobalamin status in healthy women and their offspring.
- 2007
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Ingår i: Journal of Nutrition. - 0022-3166 .- 1541-6100. ; 137:8, s. 1863-1867
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Tidskriftsartikel (refereegranskat)abstract
- Compromised cobalamin status during pregnancy may put both mother and child at risk of deficiency during lactation and subsequent development. We investigated whether changes in cobalamin status during pregnancy are associated with impaired status in the mother and the cord. Plasma cobalamin, methylmalonic acid (MMA), and holotranscobalamin (holoTC) concentrations were determined in 92 women at preconception, 8, 20, and 32 wk of pregnancy, at labor, and in the cord. All variables [geometric mean percentiles 10, 90 (P(10), P(90))] were significantly reduced from preconception [cobalamin: 293 (155, 535) pmol/L; holoTC: 63 (38,98) pmol/L; MMA: 0.12 (0.09, 0.17) micromol/L] by 20 wk of pregnancy [cobalamin: 230 (123, 432) pmol/L; holoTC: 48 (34,78) pmol/L; MMA: 0.11 (0.08, 0.15) micromol/L P < 0.001]. Plasma cobalamin and holoTC remained lower throughout the remainder of pregnancy [32 wk: 198 (107, 339); labor: 224 (117, 444); P < 0.001] and [32 wk: 45 (26,82); labor: 40 (23,79); P < 0.05], respectively. By 32 wk, MMA was greater than preconception [0.14 (0.09, 0.20) micromol/L; P < 0.01]. Plasma holoTC at 32 wk and at labor was negatively correlated with cord MMA (r = -0.51, P < 0.001 and r = -0.40, P < 0.01, respectively). Women with lower holoTC at preconception had greater increases in MMA at 32 wk and at labor. Maternal MMA at 32 wk and at labor was significantly and independently associated with cord MMA only in women with lower holoTC at preconception (regression models: R(2) = 0.707, 0.682, respectively; P < 0.01). The moderate increases observed in the cobalamin biomarker, MMA, during pregnancy may indicate a functional depletion in intracellular cobalamin status.
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| 2. |
- Riedel, Bettina M., et al.
(författare)
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Transcobalamin polymorphism 67A-> G, but not 776C-> G, affects serum holotranscobalamin in a cohort of healthy middle-aged men and women
- 2011
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Ingår i: Journal of Nutrition. - Bethesda, Md. : Elsevier BV. - 0022-3166 .- 1541-6100. ; 141:10, s. 1784-1790
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Tidskriftsartikel (refereegranskat)abstract
- Two polymorphic variants in the gene coding for transcobalamin II (TCN2), TCN2 776C-> G and TCN2 67A-> G, may alter serum holotranscobalamin (holoTC), which in turn may affect cellular uptake of cobalamin (Cbl) and thereby Cbl status indicators. We studied the effects of TCN2 776C- > G and TCN2 67A- > G on blood concentrations of holoTC, Cbl, methylmalonic acid (MMA), and total homocysteine (tHcy) in 2411 individuals (50-64 y) that had been selected on the basis of these TCN2 genotypes from 10601 Norwegian inhabitants. The serum holoTC concentration was lower in TCN2 67AG (55 +/- 0.75 pmol/L) and 67GG (48 +/- 2.14 pmol/L) than in 67AA (62 +/- 0.67 pmol/L) (P < 0.001) but did not differ among TCN2 776C-> G genotypes. The polymorphisms interacted as serum holoTC determinants (P= 0.001) and the presence of TCN2 67AG and GG in strata of 776CC and CG, but not 776GG, increased the risk of having serum holoTC <45.6 pmol/L [tertile 1 vs. tertiles 2 and 3: OR = 2.5(95% CI 1.8-3.5) for 67AG; OR = 5.7 (95% Cl 3.5-9.1) for 67GG in 776CC; OR = 2.1 195% Cl 1.6-2.9) for 67AG; and OR = 4.5 (95% Cl 2.4-8.2) for 67GG in 776CG; all P < 0.0011. Plasma MMA, tHcy, and Cbl were not affected by either polymorphism. In summary, serum holoTC, but not plasma Cbl, MMA, or tHcy, varied according to TCN2 67A-> G genotypes. It remains to be determined whether this polymorphic effect on serum holoTC alters its diagnostic utility as Cbl status indicator.
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