Development of a Compartmental Model for Studying Vitamin A Kinetics and Status in Theoretical Lactating Women

Veronica Lopez-Teros, Michael H. Green*, Jessica Avila-Prado, Joanne B. Green

*Autor correspondiente de este trabajo

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

1 Cita (Scopus)

Resumen

Background: Low vitamin A status and suboptimal milk vitamin A concentrations are problems in many populations worldwide. However, limited research has been done on whole-body vitamin A kinetics in women of reproductive age, especially during lactation. Objectives: Goals were to develop compartmental models describing retinol kinetics in theoretical nonlactating (NL) and lactating (L) women and to determine whether the retinol isotope dilution (RID) method accurately predicted vitamin A total body stores (TBS) in the groups and individuals. Methods: We adapted 12 previously-used theoretical females with assigned values for retinol kinetic parameters and TBS (225-1348 μmol); subjects were NL or L (nursing one 3- to 6-mo-old infant) during 49-d kinetic studies after isotope dosing. We used an established compartmental model, adding a compartment for chylomicrons and, for L, another for mammary gland milk with inputs from holo-retinol-binding protein and chylomicron retinyl esters and output to milk. Using compartmental analysis, we simulated tracer responses in compartments of interest and calculated TBS using the RID equation TBS = FaS/SAp [Fa, fraction of dose in stores; S, retinol specific activity in plasma/specific activity in stores; SAp, specific activity of retinol in plasma]. Results: Models for both groups were well identified. Simulated plasma tracer responses were similar for NL and L, with L always below NL; milk tracer paralleled plasma from 10 d postdosing. Geometric mean FaS ratios (L/NL) were ∼0.75 during days 2-30. Using appropriate group FaS, RID provided accurate TBS predictions for >80% of NL and L subjects after day 18 when CV% for FaS was ∼10%. Conclusions: These new physiologically-based models for vitamin A kinetics may be useful for future research in women of reproductive age. Results indicate that, in groups like these, RID to assess an individual's vitamin A status should be done at 21-28 d after isotope dosing.

Idioma originalInglés
Páginas (desde-hasta)1621-1628
Número de páginas8
PublicaciónJournal of Nutrition
Volumen152
N.º7
DOI
EstadoPublicada - 1 jul 2022

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Publisher Copyright:
© 2022 The Author(s). Published by Oxford University Press on behalf of the American Society for Nutrition.

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