Fatty acid metabolism in human preimplantation embryos

BACKGROUND: Little is known of fatty acid metabolism in human embryos. This information would be useful in developing metabolic tests of embryo quality and improving embryo culture media. METHODS: The fatty acid composition of human embryos and their ability to accumulate 13 C labelled fatty acids was assessed in relation to the stage of development using gas-chromatography and combustion-isotope-ratio-mass spectrometry. RESULTS: Compared with embryos which did not develop beyond the 4-cell stage, those that did had significantly higher concentrations of the unsaturates, linoleic (12% versus 3%; P = 0.02) and oleic (14% versus 7%; P = 0.02), and a lower concentration of total saturates (62% versus 77%; P = 0.04). There was uptake of both 13 C linoleic and palmitic, but the developmental pattern was different for each fatty acid. The net accumulation in pmol/embryo/24h for palmitic was 1 at the 2-cell to