Poster Topical Area: Vitamins and Minerals
Location: Hall D
Poster Board Number: 512
Background: Alpha-tocopherol (αT) is critical for an infant's developing central nervous system. Most infant formulas are fortified with synthetic (all-racemic) αT, but naturally-sourced (RRR) αT preferentially accumulates in human breast milk and infant brain tissues. Hepatic αT transfer protein (αTTP) facilitates secretion of αT into lipoproteins and discriminates in favor of RRR-αT. This partially explains the selective accumulation of RRR-αT in tissues, but tissue-specific expression of binding proteins like αTTP may also affect αT deposition. The expression of αTTP was previously reported in the adult cerebellum, but expression in regions of the infant brain is unknown.
Objectives: To compare αTTP expression in the cerebellum (CB) and occipital cortex (OC) of infant rhesus macaques. Secondly, to determine the effect of dietary αT source (all-racemic or RRR) on αTTP expression and αT accumulation.
Methods: Infant rhesus macaques were fed one of two formulas (containing either RRR-αT or all-racemic-αT) or were breastfed for 6 months (n = 8, 7, 8). αTTP protein expression and αTTP mRNA expression were determined by Western blots and qPCR, respectively. Total αT concentrations and αT stereoisomer profiles were measured via HPLC.
Results: αTTP protein expression was significantly higher in the CB than the OC (p=<0.001); this was supported by mRNA expression results (p=<0.001). αTTP expression was not significantly modulated by dietary αT source. Across all diet groups, total αT accumulation was significantly higher in the OC than the CB (p=<0.001), with no significant differences between groups. RRR-αT was consistently the predominant stereoisomer across brain regions and diet groups, constituting ~92%, ~71%, and ~38% of the αT in RRR-αT-fed, all-racemic-αT-fed, and breastfed monkey brains, respectively.
Conclusions: αTTP expression, but not total αT levels, were higher in the CB than the OC of infant rhesus macaques. Dietary αT source did not affect αTTP expression. There is a biological preference for the RRR stereoisomer of αT in the infant brain.
University of Illinois at Urbana-Champaign