Poster Topical Area: Maternal, Perinatal and Pediatric Nutrition

Location: Hall D

Poster Board Number: 403

P13-146 - Effect of Maternal Vitamin D (VitD) Status on Sphingolipid Composition in Milk Fat Globule Membranes (MFGM)

Sunday, Jun 10
8:00 AM – 6:00 PM

Background: Signaling proteins are associated with sphingolipid-rich micro-domains on membranes and both the proteins and sphingolipids and/or metabolites are involved in immunity, inflammation, cell differentiation and several other protective signaling cascades. Previous studies have shown that diet affects the sphingolipid composition in milk fat globule membranes (MFGM).

Objective: Since sphingolipid (sphingomyelin [SM] and ceramide [Cer]) composition in MFGM has been shown to be affected by diet, we tested the hypothesis that SM and Cer composition is also dependent upon maternal VitD status (as measured by maternal blood 25OHD).

Design/
Methods: Whole breast milk samples from 8 mothers from 1-4 months postpartum were obtained. LC-MS was used to analyze long chain (C14-C18) and very long chain (C20-C26) acyl SM species normalized to total milk lipid inorganic phosphate.


Results: As illustrated in Figure 1, analysis of LC-MS data revealed that concentrations of very long chain sphingomyelin species (C22-SM, C24-SM and C24:1-SM) increased dramatically with increasing maternal 25OHD, with other species (C14, C20 and C26-SM) being in very low concentrations independent of VitD. Similar results were found for C22-Cer and C24-Cer (data not shown).


Conclusions: The findings are consistent with previous reports in other cells and organs that vitamin D regulates sphingolipid synthesis via VDR-responsive genes affecting MFGM sphingolipid composition, specially sphingomyelin and ceramide.



Funding Source: Funded by SC Translational Research Center UL1 TR000062 and MUSC Children's Hospital.
Figure 1. Dependence of Milk Fat Sphingomyelin Acyl Chain Length on Maternal 25(OH)D Concentration

CoAuthors: John Baatz, PhD – Medical University of SC; Danforth Newton, PhD – Medical University of SC

Carol L. Wagner

Professor of Pediatrics
Medical University of South Carolina
Charleston, South Carolina