Maternal physiological (MpH) or supraphysiological hypercholesterolaemia (MSpH) occurs during pregnancy. Cholesterol trafficking from maternal to foetal circulation requires the uptake of maternal LDL and HDL by syncytiotrophoblast and cholesterol efflux from this multinucleated tissue to ApoA-I and HDL. We aimed to determine the effects of MSPH on placental cholesterol trafficking. Placental tissue and primary human trophoblast (pHt) were isolated from pregnant women with total cholesterol <280 md/dL (MPH, n = 27) or ≥280 md/dL (MSPH, n = 28). The lipid profile in umbilical cord blood from MpH and MSpH neonates was similar. the abundance of LDL receptor (LDLR) and HDL receptor (SR-Bi) was comparable between MSpH and MpH placentas. However, LDLR was localized mainly in the syncytiotrophoblast surface and was associated with reduced placental levels of its ligand ApoB. in pHt from MSpH, the uptake of LDL and HDL was lower compared to MpH, without changes in LDLR and reduced levels of SR-BI. Regarding cholesterol efflux, in MSPH placentas, the abundance of cholesterol transporter ABCA1 was increased, while ABCG1 and SR-BI were reduced. In PHT from MSPH, the cholesterol efflux to ApoA-I was increased and to HDL was reduced, along with reduced levels of ABCG1, compared to MPH. Inhibition of SR-BI did not change cholesterol efflux in PHT. The TC content in PHT was comparable in MpH and MSpH cells. However, free cholesterol was increased in MSpH cells. We conclude that MSPH alters the trafficking and content of cholesterol in placental trophoblasts, which could be associated with changes in the placenta-mediated maternal-to-foetal cholesterol trafficking. During the progress of human pregnancy, the concentrations of total cholesterol (TC) and low-(LDL) rises in a physiological (maternal physiological hypercholesterolemia, MPH) 1,2 or supraphysiological (maternal supraphysiological hypercholesterolemia, MSPH) 3,4 way. MSPH is determined in women with TC levels above a cutoff value of 280-300 mg/dL at term of pregnancy or above the 75th percentile for the different trimesters of pregnancy 1-6. Endothelial dysfunction of the macro-and the microvascular vessels of the placenta 4,7-9 as well as development of atherosclerosis in the foetal aorta 1,2,6 has been described in pregnancies with MSPH and increased LDL levels. This information suggest that MSPH could be related to the development of cardiovascular disease in the offspring later in life 2,6,10,11. Despite the increased maternal TC and LDL concentrations, the levels of TC and triglycerides (Tg) of neonates from MSPH pregnancies are comparable to those from MPH pregnancies, suggesting a possible regulation of placental maternal-to-foetal cholesterol trafficking across the placenta 7,12 .

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During pregnancy the renin-angiotensin-aldosterone system (RAAS) undergo major changes to preserve normal blood pressure (BP), placenta blood flow and ensure a good pregnancy outcome. Abnormal aldosterone-renin metabolism is a risk factor for arterial hypertension and cardiovascular risk, but its association to pathological conditions in pregnancy remains unknown. Hence, clinical and subclinical novel biomarkers associated to these pathological conditions are encouraged to be identified. Aim: To study a cohort of normotensive pregnant women according to their serum aldosterone and plasma renin levels and assay their small extracellular vesicles (sEV) and a specific protein-cargo (LCN2, AT1R). Methods: A cohort of 54 normotensive pregnant women at term gestation. We determined the BP, serum aldosterone and plasma renin concentration. In a subgroup, we isolated their plasma sEVs and semi-quantify two EV-proteins (AT1R, LCN2). Results: We set a normal range of aldosterone and renin based in the interquartile range. We identified 5/54(9%) pregnant women with elevated aldosterone and low renin levels, and 5/54(9%) other pregnant women with low aldosterone and elevated renin levels. No differences were found in sEV-LCN2 nor sEV-AT1R. Conclusion: We found 18% normotensive pregnant women having either high aldosterone or high renin levels, suggesting a subclinical status similar to a primary aldosteronism or a hyperreninemia. Both would evolve to pathological conditions in presence a second challenge affecting the maternal vascular physiology or the BP. sEVs and its specific cargo are encouraged to be further studied in order to clarify its role as potential biomarkers of RAAS alterations in pregnant women.