Long Chain PUFA Transport in Human Term Placenta

Abstract

Docosahexanoic (DHA)⁴ and arachidonic (ARA) acids are important for proper fetal development and accumulate in the fetus during gestation. They cannot be synthesized by the fetus and must be gained instead from the maternal blood supply via the syncytiotrophoblast, the transporting epithelium of the placenta. Cell biological experiments suggest that both membrane-associated placental plasma membrane fatty acid-binding protein (pFABPpm) and fatty acid transport protein (FATP) 4 are involved in DHA uptake while fatty acid-binding proteins (FABP) are thought to be involved in intracellular trafficking of long-chain fatty acids. FABP1, 3, and 4 have been detected in the syncytiotrophoblast and there is experimental and theoretical evidence to suggest that these three FABP are under the control of hypoxia inducible factor (HIF), perhaps playing a role in fetal protection from hypoxia. Biophysical measurements reveal these FABP have a higher affinity for DHA over ARA but that affinities for both are lower than those of nonessential fatty acids. Recent research is beginning to uncover the mechanisms of DHA and ARA transmembrane and intracellular transport in the placenta, and it is suggested that maternal health and nutrition during pregnancy could be important in determining fatty acid transport and binding protein expression and, thereby, essential fatty acid delivery to the fetus.