Phospholipids in lipoproteins: compositional differences across VLDL, LDL, and HDL in pregnant women

Abstract Objective The aim of this study was to analyse the differences in the phospholipid composition of very low density (VLDL), low density (LDL) and high density lipoprotein (HDL) monolayers in pregnant lean and obese women. Methods LDL, HDL, and VLDL were isolated from plasma samples of 10 lean and 10 obese pregnant women, and their species composition of phosphatidylcholines (PC) and sphingomyelins (SM) was analysed by liquid-chromatography tandem mass-spectrometry. Wilcoxon-Mann-Whitney U test and principal component analysis (PCA) were used to investigate if metabolite profiles differed between the lean/obese group and between lipoprotein species. Results No significant differences have been found in the metabolite levels between obese and non-obese pregnant women. The PCA components 1 and 2 separated between LDL, HDL, and VLDL but not between normal weight and obese women. Twelve SM and one PCae were more abundant in LDL than in VLDL. In contrast, four acyl-alkyl-PC and two diacyl-PC were significantly higher in HDL compared to LDL. VLDL and HDL differed in three SM, seven acyl-alkyl-PC and one diacyl-PC (higher values in HDL) and 13 SM (higher in VLDL). We also found associations of some phospholipid species with HDL and LDL cholesterol. Conclusion In pregnant women phospholipid composition differs significantly in HDL, LDL and VLDL, similar to previous findings in men and non-pregnant women. Obese and lean pregnant women showed no significant differences in their lipoprotein associated metabolite profile

In vivo kinetic study of the materno-fetal fatty acid transfer in obese and normal weight pregnant women

We analyse for the first time the in vivo materno‐fetal kinetic transfer of fatty acids (FA) labelled with stable isotopes in control and obese (OB) pregnant women. Labelled FA with a similar metabolism (stearic acid: 13C‐SA; palmitic acid: 13C‐PA; oleic acid: 13C‐OA) were orally administered at −4 h, −8 h and −12 h, respectively prior to elective caesarean section to 10 pregnant women with a body mass index &gt;30 (OB) and 10 with a body mass index in the range 20–25 (NW). Placenta, venous and arterial cord blood were collected obtaining a wide range of FA enrichments. A combined experimental and computational modelling analysis was applied. FA fractional synthesis rate (FSR) in placenta was 11–12% h–1. No differences were observed between NW and normo‐lipidemic OB. It was not possible to estimate FA FSR in cord blood with this oral bolus dose approach. Computational modelling demonstrated a good fit to the data when all maternal plasma lipid classes were included but not with modelling based only on the non‐esterified FA fraction. The estimated materno‐fetal 13C‐FA transfer was ∼1%. In conclusion, our approach using multiple 13C‐FA tracers allowed us to estimated FSR in placental/maternal plasma but not in fetal/maternal compartments. Computational modelling showed a consistent time course of placental 13C‐FA transfer and predicted total fetal FA accumulation during the experiment. We conclude that, in addition to non‐esterified FA fraction in the maternal circulation, maternal plasma very low‐density lipoprotein and other lipoproteins are important contributors to placental FA transfer to the fetus.</p