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High dietary intakes of phytosterols (Phyto), such as those consumed by vegans and vegetarians, are not recommended for cholesterol-lowering in pregnant women (PW) because the safety of their use during pregnancy has not been fully established [1]. Information on Phyto in pregnancy is very limited.To characterize the maternal-fetal gradient of free and esterified Phyto at the time of delivery in humans.PW who had a term delivery at the Obstetrics and Gynecology Unit of the University Hospital of Padua (Padua, Italy), between November 2016 and March 2017, participated in the study. Fatty acids (FA), cholesterol (Chol), Chol metabolites (7-dehydrocholesterol, 7-DHChol; lathosterol, Latho; 7α-hydroxycholesterol, 7α-OHChol), and Phyto (campesterol, Camp; stigmasterol, Stigma; sitosterol, Sito) were measured in both maternal (MB) and cord blood (CB) at the time of delivery. Non-pregnant adult volunteers (Ref-NA) served as a reference.Thirty-four term PW and 12 Ref-NA signed informed consent and were studied. Plasma total Phyto concentrations in CB were up to 20-fold lower than in MB (p 0.05). Positive and significant correlations were found between total Phyto of MB-CB pairs (p 0.01), and between total FA and Camp of MB (p 0.05). Interestingly, free Chol to Chol ester ratio of CB did not differ from that of MB, and free Phyto to Phyto ester ratios were higher in CB than in MB (p 0.001). No differences were found between Phyto concentrations of MB and Ref-NA. However, free Chol to Chol ester ratio, and free Phyto to Phyto ester ratios were higher in MB than in Ref-NA (p 0.05). Chol synthesis, as indicated by 7-DHChol to 7α-OHChol, Latho to 7α-OHChol, and Latho to Sito ratios, was greatest in CB and lowest in Ref-NA.Our data suggest that free Phyto cross the human placenta more easily than Phyto ester. An elevated Stigma to Chol ratio in CB than in MB was also described for the first time. The impact of these findings on the neonatal outcomes remains to be elucidated.

Lipid-protein interactions are regarded as one of the key factors in several biophysical relevant processes. In the present work, we studied the influence of Cytochrome-c (Cyto-c) on unilamellar vesicles composed by mixing an anionic lipid (the 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol, POPG, or the cardiolipin, CL) with the zwitterionic lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), by means of small-angle X-ray scattering. Cyto-c is a component of the electron transport chain, where it has a pivotal role in transferring electrons in the inner mitochondrial membrane (IMM), which is composed of a significant amount of anionic lipids. CL is a structurally unique anionic phospholipid, containing two phosphatidylglycerol groups and four acyl chains and it is found predominantly in the IMM. The interaction of Cyto-c and CL-containing mixed vesicles has been extensively studied, and it is appointed as the major responsible for the role of Cyto-c in the cell respiration and also in the cell programmed death (apoptosis), as recently evidenced. Present results show that, in the absence of anionic lipids, Cyto-c is not able to change the structural features of POPC unilamellar vesicles. In the mixed systems, however, Cyto-c induces the formation of a multilamellar vesicles, with a bilayer-bilayer repetition distance of 11 nm, circa 4 nm larger than the staking of POPC multilamellar vesicles. This information indicates that Cyto-c, a globular protein with 3.0 nm of diameter, is probably located among the bilayers. Furthermore, such effect takes place as soon as Cyto-c is mixed in the system, as confirmed by absorption spectroscopy. The time-evolution of such process was also investigated and, interestingly, it is faster in POPG-containing vesicles than in the CL ones. Moreover, the number of staked bilayers is larger in the POPG systems.