The influence of placental metabolism on fatty acid transfer to the fetus

The factors determining Fatty acid transfer across the placenta are not fully understood. This study used a combined experimental and computational modelling approach to explore placental transfer of non-esterified fatty acids and identify rate-determining processes. The isolated perfused human placenta was used to study the uptake and transfer of [13C]-fatty acids and the release of endogenous fatty acids. Only 6.2 ± 0.8% of the maternal 13C-fatty acids taken up by the placenta was delivered to the fetal circulation. Of the unlabelled fatty acids released from endogenous lipid pools, 78 ± 5% was recovered in the maternal circulation and 22 ± 5% in the fetal circulation. Computational modelling indicated that fatty acid metabolism was necessary to explain the discrepancy between uptake and delivery of 13C-fatty acids. Without metabolism, the model overpredicts the fetal delivery of 13C-fatty acids 15 fold. Metabolic rate was predicted to be the main determinant of uptake from the maternal circulation. The microvillous membrane had a greater fatty acid transport capacity than the basal membrane. This study suggests incorporation of fatty acids into placental lipid pools may modulates their transfer to the fetus. Future work needs to focus on the factors regulating fatty acid incorporation into lipid pools.