The concentration of free holo-retinol binding protein is higher in vitamin A-sufficient than in deficient nepalese women in late pregnancy

Sandhya Sankaranarayanan, Monica Suárez, Douglas L Taren, Denise Genaro-Wolf, Burris R Duncan, Kamal Shrestha, Narayani Shrestha, Francisco J. Rosales

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Free holo-retinol binding protein (RBP) [i.e., unbound to transthyretin (TTR)] plays a role in transporting vitamin A across the placenta during pregnancy. In a cross-sectional study of clinically healthy urban women, we assessed the association among clinical and biochemical factors on estimated concentrations of free holo-RBP during the last trimester of pregnancy. Serum samples obtained from a subsample of women (n = 259), who had participated in the Night Vision Threshold Test study in Nepal, were analyzed for determinations of retinol by HPLC, and RBP, TTR, and α-1 acid glycoprotein by radial immunodiffusion. Free holo-RBP concentrations were calculated using dissociation constants for free holo- and apo-RBP. Among these women, 30% were vitamin A deficient based on either the RBP:TTR index ≤ 0.36 or serum retinol < 1.05 μmol/L. Using stepwise regression analyses, the RBP:TTR index explained 75% of the variance in free holo-RBP concentrations, whereas retinol explained only 14%. Women were classified as vitamin A sufficient (n = 185) or deficient (n = 74) using the RBP:TTR index and were stratified into 3 gestational groups (I: 24-28 wk, II: 29-33 wk, III: <33 wk). Concentrations of free holo-RBP were higher in vitamin A-sufficient women than in vitamin A-deficient women (mean ± SEM, 48.1 ± 1.2 vs. 27.6 ± 0.8 nmol/L; P < 0.001), and in a 3 x 2 factorial analysis, the interaction between gestational group and vitamin A status was significant. These results demonstrate that the RBP:TTR index is a useful proxy for free holo-RBP concentration and that vitamin A status affects its distribution.

Original languageEnglish (US)
Pages (from-to)2817-2822
Number of pages6
JournalJournal of Nutrition
Volume135
Issue number12
StatePublished - Dec 2005

Fingerprint

Retinol-Binding Proteins
retinol-binding protein
Vitamin A
vitamin A
pregnancy
Pregnancy
prealbumin
Prealbumin
night vision
Night Vision
Vision Tests
Nepal
Immunodiffusion
Third Pregnancy Trimester
Proxy
Serum
placenta
cross-sectional studies
Placenta
glycoproteins

Keywords

  • RBP:TTR index
  • Retinol
  • Retinol binding protein
  • Transthyretin
  • Vitamin A

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

Cite this

The concentration of free holo-retinol binding protein is higher in vitamin A-sufficient than in deficient nepalese women in late pregnancy. / Sankaranarayanan, Sandhya; Suárez, Monica; Taren, Douglas L; Genaro-Wolf, Denise; Duncan, Burris R; Shrestha, Kamal; Shrestha, Narayani; Rosales, Francisco J.

In: Journal of Nutrition, Vol. 135, No. 12, 12.2005, p. 2817-2822.

Research output: Contribution to journalArticle

Sankaranarayanan, S, Suárez, M, Taren, DL, Genaro-Wolf, D, Duncan, BR, Shrestha, K, Shrestha, N & Rosales, FJ 2005, 'The concentration of free holo-retinol binding protein is higher in vitamin A-sufficient than in deficient nepalese women in late pregnancy', Journal of Nutrition, vol. 135, no. 12, pp. 2817-2822.
Sankaranarayanan, Sandhya ; Suárez, Monica ; Taren, Douglas L ; Genaro-Wolf, Denise ; Duncan, Burris R ; Shrestha, Kamal ; Shrestha, Narayani ; Rosales, Francisco J. / The concentration of free holo-retinol binding protein is higher in vitamin A-sufficient than in deficient nepalese women in late pregnancy. In: Journal of Nutrition. 2005 ; Vol. 135, No. 12. pp. 2817-2822.
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