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Transplacental supply of mannose and inositol in uncomplicated pregnancies using stable isotopes.

Abstract

OBJECTIVE
The aim of this study was to determine relative contributions of transplacental flux vs. fetal production for inositol and mannose in normal term pregnancies.
STUDY DESIGN
Seven term uncomplicated pregnancies undergoing cesarean section were infused with (13)C- and (2)H-labeled isotopes of glucose, inositol, and mannose until a steady state was achieved. Maternal and fetal concentrations of labeled and unlabeled glucose, mannose, and inositol were measured using gas chromatography/mass spectroscopy. The fetomaternal molar percentage excess ratio was calculated for each glucose, mannose, and inositol.
RESULTS
The fetomaternal molar percentage excess ratio of mannose in the fetal artery (F(artery)/M) was 0.99 [97.5% confidence interval (CI), 0.91-1.07] and in the fetal vein (F(vein)/M), 1.02 (97.5% CI, 0.95-1.10). Both were not significantly different from 1.0, consistent with transplacental supply. The fetomaternal ratios for glucose were similar to mannose (fetal artery, 0.95; 97.5% CI, 0.84-1.15; and fetal vein, 0.96; 97.5% CI, 0.85-1.07). The fetomaternal ratio for inositol was significantly less than 1.0 (fetal artery, 0.08; 97.5% CI, 0.05-0.12; fetal vein, 0.12; 97.5% CI, 0.06-0.18), indicating little transplacental flux and significant fetal production.
CONCLUSION
In normal term pregnancies, fetal mannose and glucose concentrations are dependent upon maternal transplacental supply. Fetal inositol is not dependent upon transplacental supply.

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  • Publisher Full Text

    • Authors

    Staat BC, Galan HL, Harwood JE, Lee G, Marconi AM, Paolini CL, Cheung A, Battaglia FC

    Institution

    Department of Obstetrics, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA. Barton.staat@us.af.mil

    Source

    The Journal of clinical endocrinology and metabolism 97:7 2012 Jul pg 2497-502

    MeSH

    Adult
    Carbon Isotopes
    Cesarean Section
    Female
    Humans
    Hydrogen
    Infant, Newborn
    Inositol
    Isotope Labeling
    Male
    Mannose
    Maternal-Fetal Exchange
    Placenta
    Placental Circulation
    Pregnancy
    Pregnancy Complications

    Pub Type(s)

    Clinical Trial
    Journal Article
    Multicenter Study
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    22544916