Cross-sectional and longitudinal lipid determination studies in pregnant women reveal an association between increased maternal LDL cholesterol concentrations and reduced human umbilical vein relaxation

Excessive hypercholesterolaemia during pregnancy as a risk factor for endothelial dysfunction in pre-eclampsia

Pregnancy induces significant changes in the maternal cardiovascular system, and insufficient vascular endothelial adaptations to pregnancy contribute to the development of pregnancy complications such as pre-eclampsia. Pre-eclampsia is not only a major cause of maternal morbidity and mortality, but also a significant risk factor for the development of later-life cardiovascular disease. However, the specific mechanisms underlying the pathophysiology of pre-eclampsia, as well as the mechanisms for an increased susceptibility to cardiovascular disease later in life, are not fully characterized. In this review, we discuss the concept that excessive pregnancy-specific dyslipidaemia, particularly hypercholesterolaemia, is a significant risk factor for the development of pre-eclampsia. We further outline novel potential mechanisms (i.e. oxidized low-density lipoprotein receptor 1 and toll-like receptor 4) underlying endothelial dysfunction induced by excessively high cholesterol levels during pregnancy (in the context of pre-eclampsia), in addition to discussing the overall implications of having had a pregnancy complicated by pre-eclampsia on later-life maternal vascular health. Determining the mechanisms by which excessive, pregnancy-specific dyslipidaemia/hypercholesterolaemia impact maternal endothelial health in pregnancy, and later in life, will create a window of opportunity to diagnose and develop targeted therapy for a susceptible population of women, aiming to ultimately reduce the societal burden of cardiovascular disease.

Body mass index-dependent association between cholesteryl ester transfer protein variants and atherometabolic risk factors in gestational diabetes mellitus

OBJECTIVE

Gestational diabetes mellitus (GDM) is associated with metabolic abnormalities such as an altered serum lipid profile. This study investigated the influence of polymorphisms in the lipid metabolism-related cholesteryl ester transfer protein gene (CETP) on the metabolic parameters of pregnant women with GDM.

METHODS

This prospective case-control study included 665 women with GDM and 1,044 women with uncomplicated pregnancies. The PCR-restriction fragment length polymorphism method was used to genotype rs708272 and rs1800775 single nucleotide polymorphisms (SNPs). Lipid and glucose metabolic parameters were assessed. Genetic associations with related traits were analyzed.

RESULTS

Genotype distributions of rs708272 and rs1800775 in patients with GDM were similar to those in normal controls. However, the two CETP SNPs were associated with altered plasma total cholesterol (TC), high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C) concentrations in patients with GDM and in control pregnant women. Additional subgroup analysis demonstrated that the rs708272 polymorphism was associated with variations in triglyceride (TGs), TC, LDL-C, and apolipoprotein B (ApoB) levels in patients with overweight or obesity GDM, whereas both polymorphisms were associated with glucose metabolic traits (plasma insulin, glucose, or insulin) and the insulin resistance index in patients with GDM without obesity.

CONCLUSIONS

In patients with GDM, the rs708272 polymorphism was associated with atherogenic lipid levels (TG, TC, LDL-C, and ApoB), whereas the rs708272 and rs1800775 polymorphisms were associated with glucose metabolism and insulin resistance parameters, which were influenced by the body mass index. These results suggest that genetic associations with atherogenic metabolic factors may increase the risk of adverse outcomes in mothers with GDM and their offspring.

Early statin exposure influences cardiac and skeletal development with implications for ion channel transcriptomes in zebrafish

Statins, widely prescribed for cholesterol management by inhibiting HMG-CoA reductase in the cholesterol biosynthesis pathway, may also influence vertebrate development. In this study, we investigated the developmental effects of two widely used statins, atorvastatin (ATO) and pravastatin (PRA), on zebrafish offspring. For ATO, we administered doses classified as low (1 μM), medium (5 μM), and high (10 μM), while for PRA, the corresponding concentrations were set at low (18 μM), medium (180 μM), and high (270 μM). Our results showed significant reductions in birth and hatching rates, along with decreased body length in offspring at all ATO concentrations and medium to high PRA concentrations. A notable increase in malformation rates, especially in the spine and heart, was observed across all ATO treatments and in medium and high PRA groups. Additionally, we observed reduced heart contraction rates, decreased heart size, lower bone volumes, and diminished expression of mRNA osteogenic markers. Elevated venous sinus-artery bulb (SV-BA) ratios, increased thoracic area, and abnormal cartilage development were also prominent in all ATO-treated groups. Transcriptome analysis revealed alterations in genes predominantly associated with ion channels. These findings provide insights into the potential impacts of specific concentrations of statins on offspring development and highlight potential gene interactions with statins.

Intrauterine developmental origin, programming mechanism, and prevention strategy of fetal-originated hypercholesterolemia

There is increasing evidence that hypercholesterolemia has an intrauterine developmental origin. However, the pathogenesis of fetal-originated is still lacking in a theoretical system, which makes its clinical early prevention and treatment difficult. It has been found that an adverse environment during pregnancy (e.g., xenobiotic exposure) may lead to changes in fetal blood cholesterol levels through changing maternal cholesterol metabolic function and/or placental cholesterol transport function and may also directly affect the liver cholesterol metabolic function of the offspring in utero and continue after birth. Adverse environmental conditions during pregnancy may also raise maternal glucocorticoid levels and promote the placental glucocorticoid barrier opening, leading to fetal overexposure to maternal glucocorticoids. Intrauterine high-glucocorticoid exposure can alter the liver cholesterol metabolism of offspring, resulting in an increased susceptibility to hypercholesterolemia after birth. Abnormal epigenetic modifications are involved in the intrauterine programming mechanism of fetal-originated hypercholesterolemia. Some interventions targeted at pregnant mothers or offspring in early life have been proposed to effectively prevent and treat the development of fetal-originated hypercholesterolemia. In this paper, the recent research progress on fetal-originated hypercholesterolemia was reviewed, with emphasis on intrauterine maternal glucocorticoid programming mechanisms, in order to provide a theoretical basis for its early clinical warning, prevention, and treatment.

Evidence for hypoxia-induced dysregulated cholesterol homeostasis in preeclampsia: Insights into the mechanisms from human placental cells and tissues

Preeclampsia (PE) poses a considerable risk to the long-term cardiovascular health of both mothers and their offspring due to a hypoxic environment in the placenta leading to reduced fetal oxygen supply. Cholesterol is vital for fetal development by influencing placental function. Recent findings suggest an association between hypoxia, disturbed cholesterol homeostasis, and PE. This study investigates the influence of hypoxia on placental cholesterol homeostasis. Using primary human trophoblast cells and placentae from women with PE, various aspects of cholesterol homeostasis were examined under hypoxic and hypoxia/reoxygenation (H/R) conditions. Under hypoxia and H/R, intracellular total and non-esterified cholesterol levels were significantly increased. This coincided with an upregulation of HMG-CoA-reductase and HMG-CoA-synthase (key genes regulating cholesterol biosynthesis), and a decrease in acetyl-CoA-acetyltransferase-1 (ACAT1), which mediates cholesterol esterification. Hypoxia and H/R also increased the intracellular levels of reactive oxygen species and elevated the expression of hypoxia-inducible factor (HIF)-2α and sterol-regulatory-element-binding-protein (SREBP) transcription factors. Additionally, exposure of trophoblasts to hypoxia and H/R resulted in enhanced cholesterol efflux to maternal and fetal serum. This was accompanied by an increased expression of proteins involved in cholesterol transport such as the scavenger receptor class B type I (SR-BI) and the ATP-binding cassette transporter G1 (ABCG1). Despite these metabolic alterations, mitogen-activated-protein-kinase (MAPK) signaling, a key regulator of cholesterol homeostasis, was largely unaffected. Our findings indicate dysregulation of cholesterol homeostasis at multiple metabolic points in both the trophoblast hypoxia model and placentae from women with PE. The increased cholesterol efflux and intracellular accumulation of non-esterified cholesterol may have critical implications for both the mother and the fetus during pregnancy, potentially contributing to an elevated cardiovascular risk later in life.

Longitudinal changes of oxidative stress and PON1 lactonase activity and status in older pregnant women undergoing assisted reproductive technology: a prospective nested case-control study

BACKGROUND

Childbearing in women with advanced maternal age (AMA) has increased the need for artificial reproductive technology (ART). ART and oxidative stress are associated with many pregnancy complications. Paraoxonase (PON) 1 is one of the key components responsible for antioxidative activity in high-density lipoprotein (HDL). This study aimed to investigate the longitudinal changes of oxidative stress and PON1 lactonase activity and status in older women undergoing ART.

METHODS

This prospective nested case-control study included 129 control and 64 ART women. Blood samples were obtained respectively at different stages of pregnancy. PON1 level and lactonase activity were assessed using 7-O-diethylphosphoryl-3-cyano-4-methyl-7-hydroxycoumarin (DEPCyMC) and 5-thiobutyl butyrolactone (TBBL) as a substrate, respectively. A normalized lactonase activity (NLA) was estimated based on the ratio of TBBLase to DEPCyMCase activity. Serum total oxidant status (TOS), total antioxidant capacity (TAC), malondialdehyde (MDA), homocysteine (HCY), PON1 C-108T and Q192R genetic polymorphisms, and metabolic parameters were analyzed.

RESULTS

Lactonase activity and level of PON1 gradually decreased with pregnancy progression, while glycolipid metabolism parameters and TAC levels increased with pregnancy progression or significantly raised during the 2nd and 3rd trimesters, and NLA of PON1, TOS, OSI, MDA, and HCY significantly increased before delivery in the ART and control groups. Compared with the control women, the ART women had substantially higher or relatively high lactonase activity and NLA of PON1 and TAC during pregnancy; higher triglyceride (TG), total cholesterol, low-density lipoprotein cholesterol, atherogenic index, apolipoprotein (apo) B, and apoB/apoA1 ratio in the 1st trimester; and higher fasting glucose, fasting insulin, homeostatic model assessment of insulin resistance, and TG levels before delivery. No significant differences were found in the frequencies of PON1 C-108T and Q192R genotypes and alleles between the ART and control groups.

CONCLUSIONS

Women with AMA undergoing ART had higher TAC, PON1 lactonase activity, and PON1 NLA than control women, suggesting increased compensatory antioxidant capacity in ART women, thus showing higher sensitivity to oxidative stress-related injury and diseases.

Maternal Supraphysiological Hypercholesterolemia Is Accompanied by Shifts in the Composition and Anti-Atherogenic Functions of Maternal HDL along with Maternal Cardiovascular Risk Markers at Term of Pregnancy

BACKGROUND

Maternal physiological hypercholesterolemia (MPH) occurs in pregnancy for a proper fetal development. When cholesterol increases over the physiological range, maternal supraphysiological hypercholesterolemia (MSPH) is described, a condition underdiagnosed by a lack of evidence showing its biological and clinical relevance.

AIM

To determine if MSPH associates with maternal vascular dysfunction, along with changes in the composition and function of maternal HDL leading to increased cardiovascular risk.

METHODS

This study included 57 women at term of pregnancy in which a lipid profile was determined.

RESULTS

Maternal total cholesterol (TC) and LDL but not HDL were increased in MSPH women. The isolated HDL from a subgroup of MSPH women had a lower protein abundance and a reduced activity of the antioxidant enzyme PON1; however, an increased antioxidant capacity compared to MPH was observed, along with higher serum levels of α-tocopherol. Moreover, HDL from a subgroup of MSPH women had a lower capacity to induce NO synthesis in endothelial cells compared to MPH. In the circulation, we observed a reduced total antioxidant capacity and augmented levels of soluble VCAM, ApoB, ApoCII, ApoCIII, IL-10, and IL-12p70, as well as the cardiovascular risk ratio ApoB/ApoAI, compared to MPH women.

CONCLUSION

MSPH women present dysfunctional HDL and increased atherogenic cardiovascular risk factors.

Small extracellular vesicles from pregnant women with maternal supraphysiological hypercholesterolemia impair endothelial cell function in vitro

Maternal physiological hypercholesterolemia (MPH, maternal total cholesterol (TC) levels at term of pregnancy ≤280 mg/dl) occurs to assure fetal development. Maternal supraphysiological hypercholesterolemia (MSPH, TC levels >280 mg/dl) is a pathological condition associated with maternal, placental, and fetal endothelial dysfunction and early neonatal atherosclerosis development. Small extracellular vesicles (sEVs) are delivered to the extracellular space by different cells, where they modulate cell functions by transporting active signaling molecules, including proteins and miRNA.

AIM

To determine whether sEVs from MSPH women could alter the function of endothelial cells (angiogenesis, endothelial activation and nitric oxide synthesis capacity).

METHODS

This study included 24 Chilean women (12 MPH and 12 MSPH). sEVs were isolated from maternal plasma and characterized by sEV markers (CD9, Alix and HSP70), nanoparticle tracking analysis, transmission electron microscopy, and protein and cholesterol content. The endothelial cell line HMEC-1 was used to determine the uptake of labeled sEVs and the effects of sEVs on cell viability, endothelial tube formation, endothelial cell activation, and endothelial nitric oxide expression and function.

RESULTS

In MSPH women, the plasma concentration of sEVs was increased compared to that in MPH women. MSPH-sEVs were highly taken up by HMEC-1 cells and reduced angiogenic capacity and the expression and activity of eNOS without changing cell viability or endothelial activation.

CONCLUSION

sEVs from MSPH women impair angiogenesis and nitric oxide synthesis in endothelial cells, which could contribute to MSPH-associated endothelial dysfunction.

Genomic study of maternal lipid traits in early pregnancy concurs with four known adult lipid loci

BACKGROUND

Blood lipids during pregnancy are associated with cardiovascular diseases and adverse pregnancy outcomes. Genome-wide association studies (GWAS) in predominantly male European ancestry populations have identified genetic loci associated with blood lipid levels. However, the genetic architecture of blood lipids in pregnant women remains poorly understood.

OBJECTIVE

Our goal was to identify genetic loci associated with blood lipid levels among pregnant women from diverse ancestry groups and to evaluate whether previously known lipid loci in predominantly European adults are transferable to pregnant women.

METHODS

The trans-ancestry GWAS were conducted on serum levels of total cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL) and triglycerides during first trimester among pregnant women from four population groups (608 European-, 623 African-, 552 Hispanic- and 235 East Asian-Americans) recruited in the NICHD Fetal Growth Studies cohort. The four GWAS summary statistics were combined using trans-ancestry meta-analysis approaches that account for genetic heterogeneity among populations.

RESULTS

Loci in CELSR2 and APOE were genome-wide significantly associated (p-value < 5×10-8) with total cholesterol and LDL levels. Loci near CETP and ABCA1 approached genome-wide significant association with HDL (p-value = 2.97×10-7 and 9.71×10-8, respectively). Less than 20% of previously known adult lipid loci were transferable to pregnant women.

CONCLUSION

This trans-ancestry GWAS meta-analysis in pregnant women identified associations that concur with four known adult lipid loci. Limited replication of known lipid-loci from predominantly European study populations to pregnant women underlines the need for genomic studies of lipids in ancestrally diverse pregnant women.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT00912132.

Increased Circulating Levels of PCSK9 and Pro-Atherogenic Lipoprotein Profile in Pregnant Women with Maternal Supraphysiological Hypercholesterolemia

Maternal physiological hypercholesterolemia (MPH) occurs during pregnancy to assure fetal development. Some pregnant women develop maternal supraphysiological hypercholesterolemia (MSPH) characterized by increased levels of low-density lipoprotein (LDL). We aim to determine if proprotein convertase subtilisin/kexin type 9 (PCSK9) levels (a protein that regulate the availability of LDL receptor in the cells surface), as well as the composition and function of LDL, are modulated in MSPH women. This study included 122 pregnant women. Maternal total cholesterol (TC), LDL, triglycerides and PCSK9 increased from first (T1) to third trimester (T3) in MPH women. At T3, maternal TC, LDL, PCSK9 and placental abundances of PCSK9 were significantly higher in MPSH compared to MPH. Circulating PCSK9 levels were correlated with LDL at T3. In MSPH women, the levels of lipid peroxidation and oxidized LDL were significantly higher compared to MPH. LDL isolated from MSPH women presented significantly higher triglycerides and ApoB but lower levels of ApoAI compared to MPH. The formation of conjugated dienes was earlier in LDL from MSPH and in endothelial cells incubated with these LDLs; the levels of reactive oxygen species were significantly higher compared to LDL from MPH. We conclude that increased maternal PCSK9 would contribute to the maternal elevated levels of pro-atherogenic LDL in MSPH, which could eventually be related to maternal vascular dysfunction.

Perinatal Outcomes After Statin Exposure During Pregnancy

IMPORTANCE

Statins are the drug class most commonly used to treat hyperlipidemia. Recently, they have been used during pregnancy for the prevention or treatment of preeclampsia. However, the safety of statin use during pregnancy has been questioned, and the sample sizes of most previous studies have been small.

OBJECTIVE

To examine the perinatal outcomes among offspring associated with maternal use of statins during pregnancy.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 1 443 657 pregnant women 18 years of age or older with their first infant born during the period from January 1, 2004, to December 31, 2014. Data for this study were taken from the Taiwan National Health Insurance Research Database. Statistical analysis was performed from April 7, 2020, to July 31, 2021.

EXPOSURES

Maternal statin use during pregnancy.

MAIN OUTCOMES AND MEASURES

Women who have received a diagnosis of hyperlipidemia before pregnancy and who were receiving prescription statins during pregnancy were the statin-exposed group. Data on congenital anomalies, birth weight, gestational age, preterm birth, low birth weight, very low birth weight, fetal distress, and Apgar score were compared between participants with and partcipants without statin exposure during pregnancy. Risk ratios (RRs) were calculated by multivariable analyses using Poisson regression models to adjust for potential confounders. Subgroup analysis was performed to compare offspring of women who used statins for more than 3 months prior to pregnancy and maintained or stopped statin use after pregnancy.

RESULTS

A total of 469 women (mean [SD] age, 32.6 [5.4] years; mean [SD] gestational age, 38.4 [1.6] weeks) who used statins during pregnancy and 4690 age-matched controls (mean [SD] age, 32.0 [4.9] years; mean [SD] gestational age, 37.3 [2.4] weeks) with no statin exposure during pregnancy were enrolled. After controlling for maternal comorbidities and age, low birth weight was more common among offspring in the statin-exposed group (RR, 1.51 [95% CI, 1.05-2.16]), with a greater chance of preterm birth (RR, 1.99 [95% CI, 1.46-2.71]), and a lower 1-minute Apgar score (RR, 1.83 [95% CI, 1.04-3.20]). Congenital anomalies were not associated with statin exposure during pregnancy. In addition, multivariable analysis showed that there was no association between statin use for periconceptual hyperlipidemia and adverse perinatal outcomes among women who had used statins prior to pregnancy.

CONCLUSIONS AND RELEVANCE

This study suggests that statins may be safe when used during pregnancy because there was no association with congenital anomalies, but caution is needed because of an increased risk of low birth weight and preterm labor. The data also suggest that statins could be safely used during pregnancy for women with long-term use of statins before pregnancy.

Increased Fetal Cardiovascular Disease Risk: Potential Synergy Between Gestational Diabetes Mellitus and Maternal Hypercholesterolemia

Cardiovascular diseases (CVD) remain a major cause of death worldwide. Evidence suggests that the risk for CVD can increase at the fetal stages due to maternal metabolic diseases, such as gestational diabetes mellitus (GDM) and maternal supraphysiological hypercholesterolemia (MSPH). GDM is a hyperglycemic, inflammatory, and insulin-resistant state that increases plasma levels of free fatty acids and triglycerides, impairs endothelial vascular tone regulation, and due to the increased nutrient transport, exposes the fetus to the altered metabolic conditions of the mother. MSPH involves increased levels of cholesterol (mainly as low-density lipoprotein cholesterol) which also causes endothelial dysfunction and alters nutrient transport to the fetus. Despite that an association has already been established between MSPH and increased CVD risk, however, little is known about the cellular processes underlying this relationship. Our knowledge is further obscured when the simultaneous presentation of MSPH and GDM takes place. In this context, GDM and MSPH may substantially increase fetal CVD risk due to synergistic impairment of placental nutrient transport and endothelial dysfunction. More studies on the separate and/or cumulative role of both processes are warranted to suggest specific treatment options.

Maternal malnutrition and anaemia in India: dysregulations leading to the 'thin-fat' phenotype in newborns

Maternal and child malnutrition and anaemia remain the leading factors for health loss in India. Low birth weight (LBW) offspring of women suffering from chronic malnutrition and anaemia often exhibit insulin resistance and infantile stunting and wasting, together with increased risk of developing cardiometabolic disorders in adulthood. The resulting self-perpetuating and highly multifactorial disease burden cannot be remedied through uniform dietary recommendations alone. To inform approaches likely to alleviate this disease burden, we implemented a systems-analytical approach that had already proven its efficacy in multiple published studies. We utilised previously published qualitative and quantitative analytical results of rural and urban field studies addressing maternal and infantile metabolic and nutritional parameters to precisely define the range of pathological phenotypes encountered and their individual biological characteristics. These characteristics were then integrated, via extensive literature searches, into metabolic and physiological mechanisms to identify the maternal and foetal metabolic dysregulations most likely to underpin the 'thin-fat' phenotype in LBW infants and its associated pathological consequences. Our analyses reveal hitherto poorly understood maternal nutrition-dependent mechanisms most likely to promote and sustain the self-perpetuating high disease burden, especially in the Indian population. This work suggests that it most probably is the metabolic consequence of 'ill-nutrition' - the recent and rapid dietary shifts to high salt, high saturated fats and high sugar but low micronutrient diets - over an adaptation to 'thrifty metabolism' which must be addressed in interventions aiming to significantly alleviate the leading risk factors for health deterioration in India.

High total cholesterol and triglycerides levels increase arginases metabolism, impairing nitric oxide signaling and worsening fetoplacental endothelial dysfunction in gestational diabetes mellitus pregnancies

During human pregnancy, maternal physiological dyslipidemia (MPD) supports fetal development. However, some women develop maternal supraphysiological dyslipidemia (MSPD: increased total cholesterol (TC) and triglycerides (TG) levels). MSPD is present in normal and pregnancies with gestational diabetes mellitus (GDM). Both pathologies associate with fetoplacental endothelial dysfunction, producing alterations in nitric oxide (NO)-L-arginine/arginase metabolism. Nevertheless, the effect of MSPD on GDM, and how this synergy alters fetoplacental endothelial function is unknown, which is the aim of this study. 123 women at term of pregnancy were classified as MPD (n=40), MSPD (n=35), GDM with normal lipids (GDM- MPD, n=23) and with increased lipids (GDM-MSPD, n=25). TC ≥291 mg/dL and TG ≥275 mg/dL were considered as MSPD. Endothelial NO synthase (eNOS), human cationic amino acid transporter 1 (hCat1), and arginase II protein abundance and activity, were assayed in umbilical vein endothelial cells. In MSPD and MSPD-GDM, TC and TG increased respect to MPD and MPD-GDM. eNOS activity was reduced in MSPD and MSPD-GDM, but increased in MPD-GDM compared with MPD. No changes were observed in eNOS protein. However, decreased tetrahydrobiopterin levels were observed in all groups compared with MPD. Increased hCat1 protein and L-arginine transport were observed in both GDM groups compared with MPD. However, the transport was higher in GDM-MSPD compared to GDM-MPD. Higher Arginase II protein and activity were observed in MSPD-GDM compared with MPD. Thus, MSPD in GDM pregnancies alters fetal endothelial function associated with NO metabolism.

Effects of lipoproteins on endothelial cells and macrophages function and its possible implications on fetal adverse outcomes associated to maternal hypercholesterolemia during pregnancy

Hypercholesterolemia is one of the main risk factors associated with atherosclerosis and cardiovascular disease, the leading cause of death worldwide. During pregnancy, maternal hypercholesterolemia develops, and it can occur in a physiological (MPH) or supraphysiological (MSPH) manner, where MSPH is associated with endothelial dysfunction and early atherosclerotic lesions in the fetoplacental vasculature. In the pathogenesis of atherosclerosis, endothelial activation and endothelial dysfunction, characterized by an imbalance in the bioavailability of nitric oxide, contribute to the early stages of this disease. Macrophages conversion to foam cells, cholesterol efflux from these cells and its differentiation into a pro- or anti-inflammatory phenotype are also important processes that contribute to atherosclerosis. In adults it has been reported that native and modified HDL and LDL play an important role in endothelial and macrophage function. In this review it is proposed that fetal lipoproteins could be also relevant factors involved in the detrimental vascular effects described in MSPH. Changes in the composition and function of neonatal lipoproteins compared to adults has been reported and, although in MSPH pregnancies the fetal lipid profile does not differ from MPH, differences in the lipidomic profiles of umbilical venous blood have been reported, which could have implications in the vascular function. In this review we summarize the available information regarding the effects of lipoproteins on endothelial and macrophage function, emphasizing its possible implications on fetal adverse outcomes associated to maternal hypercholesterolemia during pregnancy.

Associations of maternal metabolic profile with placental and fetal cerebral and cardiac hemodynamics

OBJECTIVE

Maternal obesity and metabolic health affect pregnancy outcomes. We examined whether maternal metabolic profiles are associated with placental and fetal hemodynamics.

STUDY DESIGN

In a population-based prospective cohort study among 1175 women we examined the associations of an adverse maternal metabolic profile in early pregnancy with placental, fetal cerebral and cardiac hemodynamic development. We obtained maternal pre-pregnancy BMI by questionnaire and measured blood pressure, cholesterol, triglycerides and glucose concentrations at a median gestational age of 12.6 (95 % range 9.6-17.1) weeks. An adverse maternal metabolic profile was defined as ≥4 risk factors. Placental and fetal hemodynamics were measured by pulsed-wave-Doppler at a median gestational age of 30.3 (95 % range 28.8-32.3) weeks.

RESULTS

An adverse maternal metabolic profile was associated with a 0.29 Z-score higher (95 %CI 0.08-0.50) fetal cerebral middle artery pulsatility index (PI), but not with placental or fetal cardiac hemodynamic patterns. When the individual components of an adverse maternal metabolic profile were assessed, we observed that higher maternal total cholesterol and triglyceride concentrations were associated with a higher cerebral middle artery PI (Z-score, 0.09 (95 %CI 0.02-0.15), 0.09 (95 %CI 0.03-0.15) per Z-score increase). Higher total and HDL maternal cholesterol concentrations were also associated with a higher aorta ascendens peak systolic velocity (PSV) Z-score, 0.08 (95 %CI 0.01-0.14)), and a larger left cardiac output (Z-score, 0.08 (95 %CI 0.00-0.15), respectively).

CONCLUSION

An adverse maternal metabolic profile, especially higher cholesterol and triglycerides concentrations, are associated with increased fetal cerebral vascular resistance and larger fetal aorta ascendens diameter, PSV and left cardiac output, but not with placental vascular resistance indices. Further studies are needed to identify long-term consequences of the observed associations.

Cholesterol uptake and efflux are impaired in human trophoblast cells from pregnancies with maternal supraphysiological hypercholesterolemia

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.

Maternal lipid profiles vs. fetal growth and cord blood hematopoietic cells: weak associations in healthy Korean newborn-mother pairs

BACKGROUND

We aimed to define the maternal lipid profiles that are associated with fetal growth and cord blood (CB) hematopoietic cells in healthy Korean full-term newborns.

METHODS

A total of 608 fetal-maternal pairs were enrolled; mothers voluntarily donated CB with informed consent. We analyzed birth weight (BW) as a marker of fetal growth, and we examined total nucleated cells (TNCs) and CD34⁺ cell concentrations of CB as markers of hematopoietic progenitor cell (HPC) contents. We also analyzed maternal lipid levels and investigated their associations with BW, TNCs and CD34⁺ cells.

RESULTS

Maternal triglycerides (TG) showed a significant positive association with BW and CD34⁺ cells, and low-density lipoprotein (LDL) showed a negative association with BW and CD34⁺ cells. Though not statistically significant, higher maternal TG showed a tendency toward higher levels of TNCs. Maternal TG was independently and positively correlated with BW, and maternal LDL was independently and negatively correlated with CD34⁺ cells, although the impacts were not as strong, as indicated by small beta coefficients (0.157 and -0.226, respectively).

CONCLUSIONS

We were able to investigate the association of maternal lipid profiles with BW and CB HPCs in healthy Korean newborn-mother pairs in this study. Both BW and the HPC contents showed independent associations with maternal TG and LDL, although the effect of maternal lipid levels on fetal growth and HPCs was not strong in the normal healthy population. Because maternal lipid levels were assessed once in the healthy fetal-maternal pairs, we could not investigate those associations across pregnancy.

Endothelial dysfunction in pregnancy metabolic disorders

In recent years, the vascular endothelium has gained attention as a key player in the initiation and development of pregnancy disorders. Endothelium acts as an endocrine organ that preserves the homeostatic balance by responding to changes in metabolic status. However, in metabolic disorders, endothelial cells adopt a dysfunctional function, losing their normal responsiveness. During pregnancy, several metabolic changes occur, in which endothelial function decisively participates. Similarly, when pregnancy metabolic disorders occur, endothelial dysfunction plays a key role in pathogenesis. This review outlines the main findings regarding endothelial dysfunction in three main metabolic pathological conditions observed during pregnancy: gestational diabetes, hypertensive disorders, and obesity and hyperlipidemia. Organ, histological and cellular characteristics were thoroughly described. Also, we focused in discussing the underlying molecular mechanisms involved in the cellular signaling pathways that mediate responses in these pathological conditions.

Maternal supraphysiological hypercholesterolemia associates with endothelial dysfunction of the placental microvasculature

Maternal physiological or supraphysiological hypercholesterolemia (MPH, MSPH) occurs during pregnancy. MSPH is associated with foetal endothelial dysfunction and atherosclerosis. However, the potential effects of MSPH on placental microvasculature are unknown. The aim of this study was to determine whether MSPH alters endothelial function in the placental microvasculature both ex vivo in venules and arterioles from the placental villi and in vitro in primary cultures of placental microvascular endothelial cells (hPMEC). Total cholesterol < 280 mg/dL indicated MPH, and total cholesterol ≥280 mg/dL indicated MSPH. The maximal relaxation to histamine, calcitonin gene-related peptide and adenosine was reduced in MSPH venule and arteriole rings. In hPMEC from MSPH placentas, nitric oxide synthase (NOS) activity and L-arginine transport were reduced without changes in arginase activity or the protein levels of endothelial NOS (eNOS), human cationic amino acid 1 (hCAT-1), hCAT-2A/B or arginase II compared with hPMEC from MPH placentas. In addition, it was shown that adenosine acts as a vasodilator of the placental microvasculature and that NOS is active in hPMEC. We conclude that MSPH alters placental microvascular endothelial function via a NOS/L-arginine imbalance. This work also reinforces the concept that placental endothelial cells from the macro- and microvasculature respond differentially to the same pathological condition.

Foetoplacental epigenetic changes associated with maternal metabolic dysfunction

Metabolic-related diseases are attributed to a sedentary lifestyle and eating habits, and there is now an increased awareness regarding pregnancy as a preponderant window in the programming of adulthood health and disease. The developing foetus is susceptible to the maternal environment; hence, any unfavourable condition will result in foetal physiological adaptations that could have a permanent impact on its health. Some of these alterations are maintained via epigenetic modifications capable of modifying gene expression in metabolism-related genes. Children born to mothers with dyslipidaemia, pregestational or gestational obesity, and gestational diabetes mellitus, have a predisposition to develop metabolic alterations during adulthood. CpG methylation-associated alterations to the expression of several genes in the human placenta play a crucial role in the mother-to-foetus transfer of nutrients and macromolecules. Identification of epigenetic modifications in metabolism-related tissues of offspring from metabolic-altered pregnancies is essential to obtain insights into foetal programming controlling newborn, childhood, and adult metabolism. This review points out the importance of the foetal milieu in the programming and development of human disease and provides evidence of this being the underlying mechanism for the development of adulthood metabolic disorders in maternal dyslipidaemia, pregestational or gestational obesity, and gestational diabetes mellitus.

Maternal and fetal blood lipid concentrations during pregnancy differ by maternal body mass index: findings from the ROLO study

Background

Pregnancy is a time of altered metabolic functioning and maternal blood lipid profiles change to accommodate the developing fetus. While these changes are physiologically necessary, blood lipids concentrations have been associated with adverse pregnancy outcomes such as gestational diabetes, pregnancy-induced hypertension and high birth weight. As blood lipids are not routinely measured during pregnancy, there is limited information on what is considered normal during pregnancy and in fetal blood.

Methods

Data from 327 mother-child pairs from the ROLO longitudinal birth cohort study were analysed. Fasting total cholesterol and triglycerides were measured in early and late pregnancy and fetal cord blood. Intervals were calculated using the 2.5th, 50th and 97.5th centile. Data was stratified based on maternal body mass index (BMI) measured during early pregnancy. Differences in blood lipids between BMI categories were explored using ANOVA and infant outcomes of macrosomia and large-for-gestational-age (LGA) were explored using independent student T-tests and binary logistic regression.

Results

All maternal blood lipid concentrations increased significantly from early to late pregnancy. In early pregnancy, women with a BMI < 25 kg/m² had lower concentrations of total cholesterol compared to women with a BMI of 25–29.9 kg/m² (P = 0.02). With triglycerides, women in the obese category (BMI > 30 kg/m²) had higher concentrations than both women in the normal-weight and overweight category in early and late pregnancy (P < 0.001 and P = 0.03, respectively). In late pregnancy, triglyceride concentrations remained elevated in women in the obese category compared to women in the normal-weight category (P = 0.01). Triglyceride concentrations were also elevated in late pregnancy in mothers that then gave birth to infants with macrosomia and LGA (P = 0.01 and P = 0.03, respectively).

Conclusion

Blood lipid concentrations increase during pregnancy and differ by maternal BMI. These intervals could help to inform the development of references for blood lipid concentrations during pregnancy.

Trial registration

ROLO Study - ISRCTN54392969. Date of registration: 22/04/2009.

Modulation of cholesterol transport by maternal hypercholesterolemia in human full-term placenta

The significance of maternal cholesterol transporting to the fetus under normal as well as pathological circumstances is less understood. The objective of this study was to observe the effects of maternal hypercholesterolemia on placental cholesterol transportation. Human full-time placenta, maternal and venous cord blood were sampled at delivery from the pregnant women with serum total cholesterol (TC) concentrations at third trimester higher than 7.25 mM (n = 19) and the pregnant women with normal TC concentrations (n = 19). Serum lipids and expression of genes related to cholesterol transportation were measured by western blot or real-time PCR. The results indicated that serum TC, high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C) levels were significantly increased, in pregnancies, but decreased in cord blood in hypercholesterolemic group compared to the matched control group. All the subjects were no-drinking, non-smoker, and gestational disease free. The mRNA expression of lipoprotein receptors, including LDLR and VLDLR were significantly increased, while the protein expression of PCSK9 was significantly increased in hypercholesterolemic placenta. In conclusion, maternal hypercholesterolemia might decrease the transportation of cholesterol from mother to fetus because of the high levels of PCSK9 protein expression.

Insulin Is a Key Modulator of Fetoplacental Endothelium Metabolic Disturbances in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a disease of the mother that associates with altered fetoplacental vascular function. GDM-associated maternal hyperglycaemia result in fetal hyperglycaemia, a condition that leads to fetal hyperinsulinemia and altered L-arginine transport and synthesis of nitric oxide, i.e., endothelial dysfunction. These alterations in the fetoplacental endothelial function are present in women with GDM that were under diet or insulin therapy. Since these women and their newborn show normal glycaemia at term, other factors or conditions could be altered and/or not resolved by restoring normal level of circulating D-glucose. GDM associates with metabolic disturbances, such as abnormal handling of the locally released vasodilator adenosine, and biosynthesis and metabolism of cholesterol lipoproteins, or metabolic diseases resulting in endoplasmic reticulum stress and altered angiogenesis. Insulin acts as a potent modulator of all these phenomena under normal conditions as reported in primary cultures of cells obtained from the human placenta; however, GDM and the role of insulin regarding these alterations in this disease are poorly understood. This review focuses on the potential link between insulin and endoplasmic reticulum stress, hypercholesterolemia, and angiogenesis in GDM in the human fetoplacental vasculature. Based in reports in primary culture placental endothelium we propose that insulin is a factor restoring endothelial function in GDM by reversing ERS, hypercholesterolaemia and angiogenesis to a physiological state involving insulin activation of insulin receptor isoforms and adenosine receptors and metabolism in the human placenta from GDM pregnancies.