Embryonic fatty acid metabolism in diabetic pregnancy: the difference between embryoblasts and trophoblasts

Abstract

During the first days of development the preimplantation embryo is supplied with nutrients from the surrounding milieu. Maternal diabetes mellitus affects the uterine microenvironment, leading to a metabolic adaptation processes in the embryo. We analysed embryonic fatty acid (FA) profiles and expression of processing genes in rabbit blastocysts, separately in embryoblasts and trophoblasts, to determine the potential consequences of maternal diabetes mellitus on intracellular FA metabolism. Insulin-dependent diabetes was induced by alloxan in female rabbits. On day 6 post coitum, FA profiles in blastocysts (embryoblast, trophoblast and blastocoel fluid) and maternal blood were analysed by gas chromatography. The expression levels of molecules involved in FA elongation (fatty acid elongases, ELOVLs) and desaturation (fatty acid desaturases, FADSs) were measured in embryoblast and trophoblast. Maternal diabetes mellitus influenced the FA profile in maternal plasma and blastocysts. Independent from metabolic changes, rabbit blastocysts contained a higher level of saturated fatty acids (SFAs) and a lower level of polyunsaturated fatty acids (PUFAs) compared to the FA profile of the maternal plasma. Furthermore, the FA profile was altered in the embryoblast and trophoblast, differently. While SFAs (palmitic and stearic acid) were elevated in embryoblast of diabetic rabbits, PUFAs, such as docosahexaenoic acid, were decreased. In contrast, in the trophoblast, lower levels of SFAs and higher levels of oleic acid were observed. Embryoblast and trophoblast specific alterations in gene expression were found for ELOVLs and FADSs, key enzymes for FA elongation and desaturation. In conclusion, maternal diabetes mellitus alters embryonic FA metabolism differently in embryoblast and trophoblast, indicating a lineage-specific metabolic adaptive response.

The interplay between the gut microbiota and metabolism during the third trimester of pregnancy

“…Palmitic acid is a straight chain saturated fatty acid that can be absorbed from food or generated from the endogenous synthesis of some other fatty acids, carbohydrates and amino acids ( Innis, 2016 ). It was reported that palmitic acid may have adverse impacts on conception and preimplantation embryo development ( Innis, 2016 ; Rampersaud et al, 2020 ; Schindler et al, 2020 ). Interestingly, fetuses were found to accumulate palmitic acid during the last trimester of gestation.…”

Ectopic Lipid Accumulation Correlates with Cellular Stress in Rabbit Blastocysts from Diabetic Mothers

“…In addition, the metabolic profiles of the EB and TB cells are differentially affected by maternal diabetes mellitus [36]. While saturated fatty acids (palmitic and stearic acid) were elevated in the EB cells of diabetic rabbits, polyunsaturated fatty acids, such as docosahexaenoic acid, were decreased [36]. In contrast, lower levels of palmitic and stearic acid and higher levels of oleic acid were observed in the TB cells [36].…”

“…For example, EB cells tend to accumulate intracellular lipid droplets and predominantly express FABP4 and adipophilin genes [35]. In addition, the metabolic profiles of the EB and TB cells are differentially affected by maternal diabetes mellitus [36]. While saturated fatty acids (palmitic and stearic acid) were elevated in the EB cells of diabetic rabbits, polyunsaturated fatty acids, such as docosahexaenoic acid, were decreased [36].…”