Fatty acid metabolism and oxidation capacity in the placenta, which likely affects the rate and composition of
lipid delivered to the fetus remains poorly understood. Long chain
polyunsaturated fatty acids, such as
docosahexaenoic acid (DHA), are critical for fetal growth and brain development. We determined the impact of
maternal obesity on placental
fatty acid oxidation, esterification and transport capacity by measuring
PhosphatidylCholine (PC) and
LysoPhosphatidylCholine (LPC) containing DHA by mass spectrometry in mother-placenta-baby triads as well as placental free
carnitine and
acylcarnitine metabolites in women with normal and obese pre-pregnancy BMI. Placental
protein expression of
enzymes involved in beta-oxidation and esterification pathways, MFSD2a (
lysophosphatidylcholine transporter) and OCTN2 (
carnitine transporter) expression in syncytiotrophoblast microvillous (MVM) and basal (BM) membranes were determined by Western Blot.
Maternal obesity was associated with decreased umbilical cord plasma DHA in LPC and PC fractions in male, but not female, fetuses. Basal membrane MFSD2a
protein expression was increased in placenta of males of obese mothers. In female placentas, despite an increased MVM OCTN2 expression,
maternal obesity was associated with a reduced MUFA-
carnitine levels and increased esterification
enzymes. We speculate that lower DHA-PL in fetal circulation of male offspring of obese mothers, despite a significant increase in transporter expression for LPC-DHA, may lead to low DHA needed for brain development contributing to neurological consequences that are more prevalent in male children. Female placentas likely have reduced beta-oxidation capacity and appear to store FA through greater placental esterification, suggesting impaired placenta function and
lipid transfer in female placentas of obese mothers.