Background: Better understanding of the mechanisms involved in docosahexaenoic acid (DHA) transfer to the neonate may contribute to improve dietary support for infants born prematurely to mothers with placental lipid transport disorders.
Objective: We studied whether DHA supplements modify the messenger RNA (mRNA) expression of placental lipid transport proteins to allow a selective transfer of DHA to the fetus.
Design: Healthy pregnant women (n = 136) received, in a double-blind randomized trial, 500 mg DHA + 150 mg eicosapentaenoic acid, 400 microg 5-methyl-tetrahydrofolic acid, 500 mg DHA + 400 microg 5-methyl-tetrahydrofolic acid, or placebo during the second half of gestation. We analyzed the fatty acid composition of maternal and cord blood phospholipids and of placenta; we quantified placental mRNA expression of fatty acid-transport protein 1 (FATP-1), FATP-4, FATP-6, fatty acid translocase, fatty acid-binding protein (FABP) plasma membrane, heart-FABP, adipocyte-FABP, and brain-FABP.
Results: The mRNA expression of the lipid carriers assayed did not differ significantly between the 4 groups. However, the mRNA expression of FATP-1 and FATP-4 in placenta was correlated with DHA in both maternal plasma and placental phospholipids, although only FATP-4 expression was significantly correlated with DHA in cord blood phospholipids. Additionally, the mRNA expression of several membrane lipid carriers was correlated with EPA and DHA in placental triacylglycerols and with EPA in placental free fatty acids.
Conclusions: Correlation of the mRNA expression of the membrane placental proteins FATP-1 and especially of FATP-4 with maternal and cord DHA leads us to conclude that these lipid carriers are involved in placental transfer of long-chain polyunsaturated fatty acids.