Serum levels of lipids, lipoproteins and paraoxonase activity in pre-eclampsia

Metabolic profiles of meconium in preeclamptic and normotensive pregnancies

INTRODUCTION

Preeclampsia (PE) is a common vascular pregnancy disorder affecting maternal and fetal metabolism with severe immediate and long-term consequences in mothers and infants. During pregnancy, metabolites in the maternal circulation pass through the placenta to the fetus. Meconium, a first stool of the neonate, offers a view to maternal and fetoplacental unit metabolism and could add to knowledge on the effects of PE on the fetus and newborn.

OBJECTIVES

To compare meconium metabolome of infants from PE and normotensive pregnancies.

METHODS

A cohort of preeclamptic parturients and normotensive controls were recruited in Tampere University Hospital during 2019-2022. Meconium was sampled and its metabolome analyzed using liquid chromatography- mass spectrometry in 48 subjects in each group.

RESULTS

Differences in abundances of 1263 compounds, of which 19 could be annotated, were detected between the two groups. Several acylcarnitines, androsterone sulfate, three bile acids, amino acid derivatives (phenylacetylglutamine, epsilon-(gamma-glutamyl)lysine and N-(phenylacetyl)glutamic acid), as well as caffeine and paraxanthine were lower in the PE group compared to the control group. Urea and progesterone were higher in the PE group.

CONCLUSION

PE is associated with alterations in the meconium metabolome of infants. The differing abundances of several metabolites show alterations in the interaction between the fetoplacental unit and mother in PE, but whether they are a cause or an effect of the disorder remains to be further investigated.

Diagnosis of preeclampsia using metabolomic biomarkers

The diagnostic criteria for preeclampsia do not accurately reflect the pathophysiological characteristics of patients with preeclampsia. Conventional biomarkers and diagnostic approaches have proven insufficient to fully comprehend the intricacies of preeclampsia. This study aimed to screen differentially abundant metabolites as candidate biomarkers for preeclampsia. A propensity score matching method was used to perform a 1:1 match between preeclampsia patients (n = 70) and healthy control individuals (n = 70). Based on univariate and multivariate statistical analysis methods, the different characteristic metabolites were screened and identified. Least absolute shrinkage and selection operator (LASSO) regression analysis was subsequently used to further screen for differentially abundant metabolites. A receiver operating characteristic (ROC) curve was drawn to evaluate the diagnostic efficacy of the metabolites. A total of 1,630 metabolites were identified and quantified in maternal serum samples. Fifty-three metabolites were significantly increased, and two were significantly decreased in preeclampsia patients. The area under the curve (AUC) of the model composed of isobutyryl-L-carnitine and acetyl-leucine was 0.878, and the sensitivity and specificity in detecting preeclampsia were 81.4% and 87.1%, respectively. There are significant differences in metabolism between preeclampsia patients and healthy pregnant women, and a range of novel biomarkers have been identified. These findings lay the foundation for the use of metabolomic biomarkers for the diagnosis of preeclampsia.

Cholesterol Metabolic Profiling of HDL in Women with Late-Onset Preeclampsia

A specific feature of dyslipidemia in pregnancy is increased high-density lipoprotein (HDL) cholesterol concentration, which is probably associated with maternal endothelium protection. However, preeclampsia is most often associated with low HDL cholesterol, and the mechanisms behind this change are scarcely explored. We aimed to investigate changes in HDL metabolism in risky pregnancies and those complicated by late-onset preeclampsia. We analyze cholesterol synthesis (cholesterol precursors: desmosterol, 7-dehydrocholesterol, and lathosterol) and absorption markers (phytosterols: campesterol and β-sitosterol) within HDL particles (NCS_HDL), the activities of principal modulators of HDL cholesterol's content, and major HDL functional proteins levels in mid and late pregnancy. On the basis of the pregnancy outcome, participants were classified into the risk group (RG) (70 women) and the preeclampsia group (PG) (20 women). HDL cholesterol was lower in PG in the second trimester compared to RG (p < 0.05) and followed by lower levels of cholesterol absorption markers (p < 0.001 for campesterol_HDL and p < 0.05 for β-sitosterol_HDL). Lowering of HDL cholesterol between trimesters in RG (p < 0.05) was accompanied by a decrease in HDL phytosterol content (p < 0.001), apolipoprotein A-I (apoA-I) concentration (p < 0.05), and paraoxonase 1 (PON1) (p < 0.001), lecithin-cholesterol acyltransferase (LCAT) (p < 0.05), and cholesterol ester transfer protein (CETP) activities (p < 0.05). These longitudinal changes were absent in PG. Development of late-onset preeclampsia is preceded by the appearance of lower HDL cholesterol and NCS_HDL in the second trimester. We propose that reduced capacity for intestinal HDL synthesis, decreased LCAT activity, and impaired capacity for HDL-mediated cholesterol efflux could be the contributing mechanisms resulting in lower HDL cholesterol.

The involvement of long noncoding RNA APOA1-AS in the pathogenesis of preeclampsia

OBJECTIVE

Long noncoding RNAs (lncRNAs) are involved in preeclampsia (PE), and apolipoprotein A-1 antisense RNA (APOA1-AS) and has been found to be associated with a number of diseases. Our study aims to understand the involvement of APOA1-AS in PE.

METHODS

Clinically, APOA1-AS expression in early-onset severe PE (EOSPE) patients and healthy controls was detected by real-time quantitative polymerase chain reaction. In vitro experiments were divided into control [coculturing trophoblasts with human uterine microvascular endothelial cells (UtMVECs)], TNF-α [coculturing trophoblasts with UtMVECs treated with tumor necrosis factor-α (TNF-α)], and TNF-α + control siRNA/APOA1-AS siRNA groups (UtMVECs transfected with control siRNA/APOA1-AS siRNA were cocultured with trophoblasts in the presence of TNF-α). The animals were divided into normal group, PE group (PE model was established by administrating nitro-L-arginine methyl ester (L-NAME) in rats), PE + control siRNA group (PE rats were treated with control siRNA), and PE + APOA1-AS siRNA group (PE rats were treated with APOA1-AS siRNA).

RESULTS

Increased APOA1-AS was found in the placental tissues of EOSPE patients. APOA1-AS siRNA abolished the decreased integration of trophoblasts into UtMVEC networks induced by TNF-α. Furthermore, APOA1-AS siRNA improved pregnancy outcomes in PE rats with increased expression of vascular endothelial growth factor, placental growth factor, and fms-like tyrosine kinase receptor (Flt-1) but decreased expression of E-cadherin, intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1).

CONCLUSION

Downregulation of APOA1-AS protected against TNF-α-induced inhibition of trophoblast integration into endothelial networks, thus exerting protective effects against PE rats.

Upregulation of ENDOU in cytotrophoblasts from placenta complicated with preeclampsia and fetal growth restriction

Placental hypoplasia is associated with the pathophysiology of fetal growth restriction and preeclampsia. The placenta consists of differentiated trophoblasts, including cytotrophoblasts, syncytiotrophoblasts, and extravillous trophoblasts. Cytotrophoblasts are thought to have stem-like characteristics and the ability to differentiate into syncytiotrophoblasts and extravillous trophoblasts. However, it is poorly understood whether isolated cytotrophoblasts derived from hypoplastic placentas have specific features compared with those in normal placentas. This study aimed to determine the features of cytotrophoblasts in hypoplastic placentas. Differentially expressed proteins between isolated cytotrophoblasts from hypoplastic placenta with fetal growth restriction and those from the normal placenta were determined by liquid chromatography-tandem mass spectrometry. Among 6,802 proteins, 1,253 and 2,129 proteins were more than 2-fold upregulated and downregulated, respectively. Among them, ENDOU (endonuclease, poly(U) specific), which has high homology with the coronavirus endoribonuclease nonstructural protein 15 (Nsp15), showed a significantly increased expression in cytotrophoblasts from the placenta with fetal growth restriction related to preeclampsia compared with those in normal control placenta. These results provide insight into the pathological mechanisms of placental hypoplasia and additional information on preeclamptic symptoms in cases of SARS-CoV-2 infected placenta, although further investigation is needed.

Regulatory role of Apelin-13-mediated PI3K/AKT signaling pathway in the glucose and lipid metabolism of mouse with gestational diabetes mellitus

OBJECTIVE

To investigate the regulatory mechanism of Apelin-13-mediated PI3K/AKT signaling pathway in the glucose and lipid metabolism of gestational diabetes mellitus (GDM) mouse.

METHODS

GDM mice models were established and treated with Apelin-13 and/or PI3K/AKT inhibitor LY294002. Then, the indicators of glucose and lipid metabolism and the levels of inflammatory factors were detected. Besides, the levels of indicators of oxidative stress in the placenta of mice were measured. Western blotting was also carried out to determine the expression of PI3K/AKT pathway-related proteins in all groups.

RESULTS

In comparison with the Control group, mice in the GDM group presented with the continuous increase in the level of FBG as the time went on, while FINS level decreased evidently. Besides, the fetus alive ratio in the GDM group was much lower with significant increased weight of fetal mouse and weight of placenta; the mice had significant decreased levels of IL-6, IL-1β, TNF-α and MCP-1, and in the placenta, the levels of SOD, GPx, GSH and CAT were also reduced evidently, with significant downregulation of p-PI3K/PI3K and p-AKT/AKT. However, indicators above in the GDM mice treated with Apelin-13 had significant improvement as compared to those in the GDM group, and the improvement was reversed by LY294002 treatment.

CONCLUSION

Apelin-13, possibly by activating the PI3K/AKT pathway, could improve the glucose and lipid metabolism, reduce the damage caused by oxidative stress and inflammatory reaction, and protect the pancreas islet, thereby improving the pregnancy outcome of GDM mice.

Maternal serum lipids in some women with pre-eclampsia in Yaoundé

Preeclampsia is one of the most common complications of pregnancy and occurs in approximately 3-8% of all pregnancies worldwide. Although the aetiology of preeclampsia still largely remains unclear, it is thought to be related to endothelial dysfunction and can lead to serum lipid abnormalities. Therefore, this case-control study was conceived and designed with the aim to compare maternal lipid profile parameters and cardiovascular risk factors, between preeclamptic and healthy pregnancies. Blood samples were collected after overnight fasting from 48 preeclamptics and 96 healthy pregnant controls matched for age and gestational weeks and serum lipid profile concentrations were estimated and used them to calculate cardiac risk ratio I and II. There was a significant rise in serum lipid levels in pregnancies complicated by preeclampsia. These lipids turn out to be risk factor for cardiovascular diseases. Positive correlation of maternal serum lipids to high blood pressure suggests a causal relationship.

Fetal High-Density Lipoproteins: Current Knowledge on Particle Metabolism, Composition and Function in Health and Disease

Cholesterol and other lipids carried by lipoproteins play an indispensable role in fetal development. Recent evidence suggests that maternally derived high-density lipoprotein (HDL) differs from fetal HDL with respect to its proteome, size, and function. Compared to the HDL of adults, fetal HDL is the major carrier of cholesterol and has a unique composition that implies other physiological functions. Fetal HDL is enriched in apolipoprotein E, which binds with high affinity to the low-density lipoprotein receptor. Thus, it appears that a primary function of fetal HDL is the transport of cholesterol to tissues as is accomplished by low-density lipoproteins in adults. The fetal HDL-associated bioactive sphingolipid sphingosine-1-phosphate shows strong vasoprotective effects at the fetoplacental vasculature. Moreover, lipoprotein-associated phospholipase A2 carried by fetal-HDL exerts anti-oxidative and athero-protective functions on the fetoplacental endothelium. Notably, the mass and activity of HDL-associated paraoxonase 1 are about 5-fold lower in the fetus, accompanied by an attenuation of anti-oxidative activity of fetal HDL. Cholesteryl ester transfer protein activity is reduced in fetal circulation despite similar amounts of the enzyme in maternal and fetal serum. This review summarizes the current knowledge on fetal HDL as a potential vasoprotective lipoprotein during fetal development. We also provide an overview of whether and how the protective functionalities of HDL are impaired in pregnancy-related syndromes such as pre-eclampsia or gestational diabetes mellitus.

Concept and connotation of oxidative stress in preeclampsia

BACKGROUND:

Preeclampsia (PE) is a systemic pregnancy-related disorder characterized by hypertension, proteinuria, and edema. Free radicals seem to play an important role in the induction of endothelial dysfunction in PE.

AIM:

The aim of the present study was to investigate serum levels of nitric oxide (NO), peroxynitrite (ONOO⁻), paraoxonase (PON-1), malondialdehyde (MDA), and lipid profile in preeclamptic patients compared to the women with normal pregnancy.

MATERIALS AND METHODS:

A total of 68 pregnant women were recruited. They were divided into two groups - Group A, 40 women were a newly diagnosed with PE and Group B, 28 women with normal pregnancy. Anthropometric measurements including body mass index and blood pressure in accordance with biochemical measurements including NO, ONOO⁻, PON-1, MDA, and lipid profile were done for preeclamptic pregnant women compared to the controls.

RESULTS:

Pregnant women with pre-eclampsia illustrated insignificant differences in the age (31.22±2.87) compared to the age of control P > 0.05. There were significant changes in the body mass index (BMI), type of delivery and smoking status of pregnant women with pre-eclampsia compared to the control P < 0.05. Both systolic and diastolic blood pressures were high in pregnant women with pre-eclampsia compared to the control P < 0.01. PON-1 and NO serum levels were significantly decreased (P < 0.01) while ONOO⁻ and MDA serum levels were significantly increased in PE compared to the women with normal pregnancy.

CONCLUSIONS:

This study concluded that PE is associated with the augmentation of oxidative stress and reduction of endogenous antioxidant capacity regarding PON-1.

A Non-Targeted LC-MS Profiling Reveals Elevated Levels of Carnitine Precursors and Trimethylated Compounds in the Cord Plasma of Pre-Eclamptic Infants

Preeclampsia (PE) is a complex pregnancy disorder. It is not extensively known how the metabolic alterations of PE women contribute to the metabolism of newborn. We applied liquid chromatography-mass spectrometry (LC-MS) based non-targeted metabolomics to determine whether the metabolic profile of plasma from umbilical cord differs between infants born to PE and non-PE pregnancies in the FINNPEC study. Cord plasma was available from 42 newborns born from PE and 53 from non-PE pregnancies. 133 molecular features differed between PE and non-PE newborns after correction for multiple testing. Decreased levels of 4-pyridoxic acid were observed in the cord plasma samples of PE newborns when compared to non-PE newborns. Compounds representing following areas of metabolism were increased in the cord plasma of PE newborns: urea and creatine metabolism; carnitine biosynthesis and acylcarnitines; putrescine metabolites; tryptophan metabolism and phosphatidylcholines. To our knowledge, this study is the first one to apply LC-MS based metabolomics in cord plasma of PE newborns. We demonstrate that this strategy provides a global picture of the widespread metabolic alterations associated with PE and particularly the elevated levels of carnitine precursors and trimethylated compounds appear to be associated with PE at birth.

Maternal serum lipid in women with preeclampsia in Lagos: a case control study

Objective: This was to determine the serum lipid profile of preeclamptic women and their association with severity of preeclampsia.Methods: This was a case control study conducted at the Lagos University Teaching Hospital, Lagos, Nigeria. Blood samples for serum lipid estimation were collected after an overnight fast. The National Cholesterol Education Program - Adult Treatment Panel (ATP) III criteria were used to define dyslipidemia.Results: Two hundred forty women participated in the study. The mean total cholesterol of preeclamptic and normotensive women was 309.9 ± 10.4 mg/dl and 237 ± 6.8 mg/dl, respectively. Both groups of women had higher than normal mean levels of triglycerides (TG) (203.3 ± 11.0 mg/dl versus 157.5 ± 7.1 mg/dl); low-density lipoprotein (LDL)-c (156.5 ± 11.0 mg/dl versus 109.7 ± 6.9 mg/dl); high-density lipoprotein (HDL)-c (63.2 ± 2.5 mg/dl versus 55.4 ± 1.8 mg/dl) and very low-density lipoprotein (VLDL) (39.5 ± 2.0 mg/dl versus 31.5 ± 1.4 mg/dl). Fewer women with preeclampsia had isolated hypertriglyceridemia (95 versus 99%). Maternal serum total cholesterol (TC), TG, and LDL was significantly (p < .001) higher in severe, compared to mild preeclampsia. Pearson's correlation indicated that all lipids, including total cholesterol (r = 0.406) had positive correlation with preeclampsia.Conclusion: There is elevated serum lipid in pregnancy irrespective of preeclampsia developing. The positive correlation of maternal serum lipids to preeclampsia suggests a casual relationship.

High-density lipoproteins (HDL) composition and function in preeclampsia

PURPOSE

To evaluate (a) the properties of high-density lipoproteins (HDL)/cholesterol, which include apolipoprotein A-1 (ApoA1) and paraoxonase1 (PON1), both are negative predictors of cardiovascular risk and (b) HDL function, among women with preeclampsia (PE). PE is a multi-system disorder, characterized by onset of hypertension and proteinuria or other end-organ dysfunction in the second half of pregnancy. Preeclampsia is associated with increased risk for later cardiovascular disease. The inverse association between HDL, cholesterol levels and the risk of developing atherosclerotic cardiovascular disease is well-established.

METHODS

Twenty-five pregnant women [19 with PE and 6 with normal pregnancy (NP)] were recruited during admission for delivery. HDL was isolated from blood samples. PON1 activity and HDL were analyzed. An in vitro model of endothelial cells was used to evaluate the effect of HDL on the transcription response of vascular cell adhesion molecule-1 (VCAM-1) and endothelial nitric oxide synthase (eNOS) mRNA expression.

RESULTS

PON1 activity (units/ml serum) was lower in the PE group compared to normal pregnancy (NP) (6.51 ± 0.73 vs. 9.98 ± 0.54; P = 0.015). Increased ApoA1 was released from PE-HDL as compared to NP-HDL (3.54 ± 0.72 vs. 0.89 ± 0.35; P = 0.01). PE-HDL exhibited increased VCAM-1 mRNA expression and decreased eNOS mRNA expression on TNF-α stimulated endothelial cells as compared to NP-HDL.

CONCLUSIONS

HDL from women with PE reduced PON1 activity and increased ApoA1 release from HDL particles. This process was associated with increased HDL diameter, suggesting impaired HDL anti-oxidant activity. These changes might contribute to higher long-term cardiovascular risks among women with PE.

Epidemiological analysis of maternal lipid levels during the second trimester in pregnancy and the risk of adverse pregnancy outcome adjusted by pregnancy BMI

BACKGROUND

Pregnancy is accompanied by profound changes in lipid metabolism. We aimed to assess whether effects of second trimester body mass index and maternal lipid concentrations are associated with an increased risk of adverse pregnancy outcomes.

METHODS

We investigated the serum levels of maternal lipids during the second trimester in pregnancy, and analyzed associations between the lipid levels and the risk of adverse pregnancy outcome. Seven hundred and seventy-four pregnant women were enrolled in this study between February 2016 and June 2016. Multivariate logistic regression analysis was conducted to estimate the relative risk between maternal lipids and adverse pregnancy outcome.

RESULTS

Compared with the control group, during the second trimester of pregnancy, BMI, TG, and Lp(a) were risk factors for gestational diabetes mellitus; middle trimester pregnancy BMI, Lp(a), and APO-B were risk factors for pre-eclampsia; second trimester BMI and TG/HDL-C were risk factors for macrosomia; age and Lp(a) were uterine atony postpartum hemorrhage risk factors, while APO-AI was a protective factor of uterine inertia and postpartum hemorrhage; second trimester BMI, TCH, Lp(a), and TG/HDL-C were risk factors for fetal distress, while parity was a protective factor against fetal distress.

CONCLUSION

Abnormal blood lipid levels in pregnancy are significantly associated with GDM, pre-eclampsia, and other adverse pregnancy outcomes.

Oxidative profiles of LDL and HDL isolated from women with preeclampsia

BACKGROUND

Oxidative stress causes biochemical changes in lipids and proteins; these changes can induce damage to the vascular endothelium and create maternal complications that are characteristic of preeclampsia. In this study, we evaluated the oxidative profile of lipoproteins isolated from women with preeclampsia.

METHODS

Thirty women diagnosed with preeclampsia and thirty women without preeclampsia were included in the study. Lipid-damage biomarkers, including conjugated dienes, lipohydroperoxides and malondialdehyde, were measured. The reduction of nitroblue tetrazolium, the formation of dityrosines, and the carbonylation of proteins were assessed as indicators of protein damage. The protective activity of HDL-c was evaluated by the paraoxonase-I activity present on the HDL-c particles. Serum lipid profiles were also quantified in both groups. Data were analysed using Student's t test and the Pearson correlation coefficient.

RESULTS

Our results demonstrated in PE women evident oxidative changes in the lipids and proteins in HDL-c and LDL-c particles and the activity of the antioxidant enzyme PON-I decreased 59.9%. HDL-c exhibited self-defence, as demonstrated by the negative correlation between paraoxonase-I activity and the formation of lipohydroperoxides in HDL-c (r = -0.3755, p < 0.005).

CONCLUSIONS

LDL-c and HDL-c isolated from women with preeclampsia show oxidative damage to lipids and proteins. We propose an oxidative profile based on the oxidation levels indicated by each of the markers used. We also found that paraoxonase-I is inactivated in the presence of lipohydroperoxides. Antioxidant support might be helpful to reduce oxidative stress in patients with preeclampsia. Further investigations are necessary to define the association between antioxidant activities and preeclampsia.

Increased maternal and fetal cholesterol efflux capacity and placental CYP27A1 expression in preeclampsia

Preeclampsia is a pregnancy-specific condition that leads to increased cardiovascular risk in later life. A decrease in cholesterol efflux capacity is linked to CVD. We hypothesized that in preeclampsia there would be a disruption of maternal/fetal plasma to efflux cholesterol, as well as differences in the concentrations of both placental sterol 27-hydroxylase (CYP27A1) and apoA1 binding protein (AIBP). Total, HDL-, and ABCA1-mediated cholesterol effluxes were performed with maternal and fetal plasma from women with preeclampsia and normotensive controls (both n = 17). apoA1 and apoE were quantified by chemiluminescence, and 27-hydroxycholesterol (27-OHC) by GC-MS. Immunohistochemistry was used to determine placental expression/localization of CYP27A1, AIBP, apoA1, apoE, and SRB1. Maternal and fetal total and HDL-mediated cholesterol efflux capacities were increased in preeclampsia (by 10-20%), but ABCA1-mediated efflux was decreased (by 20-35%; P < 0.05). Maternal and fetal apoE concentrations were higher in preeclampsia. Fetal plasma 27-OHC levels were decreased in preeclamptic samples (P < 0.05). Placental protein expression of both CYP27A1 and AIBP were localized around fetal vessels and significantly increased in preeclampsia (P = 0.04). Placental 27-OHC concentrations were also raised in preeclampsia (P < 0.05). Increased HDL-mediated cholesterol efflux capacity and placental CYP27A1/27-OHC could be a rescue mechanism in preeclampsia, to remove cholesterol from cells to limit lipid peroxidation and increase placental angiogenesis.

Integration of metabolomic and transcriptomic networks in pregnant women reveals biological pathways and predictive signatures associated with preeclampsia

INTRODUCTION

Preeclampsia is a leading cause of maternal and fetal mortality worldwide, yet its exact pathogenesis remains elusive.

OBJECTIVES

This study, nested within the Vitamin D Antenatal Asthma Reduction Trial (VDAART), aimed to develop integrated omics models of preeclampsia that have utility in both prediction and in the elucidation of underlying biological mechanisms.

METHODS

Metabolomic profiling was performed on first trimester plasma samples of 47 pregnant women from VDAART who subsequently developed preeclampsia and 62 controls with healthy pregnancies, using liquid-chromatography tandem mass-spectrometry. Metabolomic profiles were generated based on logistic regression models and assessed using Received Operator Characteristic Curve analysis. These profiles were compared to profiles from generated using third trimester samples. The first trimester metabolite profile was then integrated with a pre-existing transcriptomic profile using network methods.

RESULTS

In total, 72 (0.9%) metabolite features were associated (p<0.01) with preeclampsia after adjustment for maternal age, race, and gestational age. These features had moderate to good discriminatory ability; in ROC curve analyses a summary score based on these features displayed an area under the curve (AUC) of 0.794 (95%CI 0.700, 0.888). This profile retained the ability to distinguish preeclamptic from healthy pregnancies in the third trimester (AUC:0.762 (95% CI 0.663, 0.860)). Additionally, metabolite set enrichment analysis identified common pathways, including glycerophospholipid metabolism, at the two time-points. Integration with the transcriptomic signature refined these results suggesting a particular role for lipid imbalance, immune function and the circulatory system.

CONCLUSIONS

These findings suggest it is possible to develop a predictive metabolomic profile of preeclampsia. This profile is characterized by changes in lipid and amino acid metabolism and dysregulation of immune response and can be refined through interaction with transcriptomic data. However validation in larger and more diverse populations is required.

[Relationship between lipid alterations during pregnancy and adverse pregnancy outcomes]

Lipids play an important role during pregnancy, and in this period major changes occur in lipoprotein metabolism. During the third trimester plasma cholesterol and triglyceride levels are substantially increased, returning to normal after delivery. Described associations between increased morbidity during pregnancy and excessive increases in plasma cholesterol and triglycerides. For this reason we have reviewed the relationship between lipid alterations, preeclampsia, gestational diabetes and preterm birth. The overall metabolic control can improve pregnancy outcomes, and the assessment of supraphysiological changes in lipid profile will classify pregnancy risk at a higher level, which would entail a stricter control.

A study of serum Apo A-1 and Apo B-100 levels in women with preeclampsia

OBJECTIVE

To investigate Apo A-1 and Apo B-100 levels and Apo B-100/Apo A-1 ratios in preeclamptic (PE) patients.

MATERIALS AND METHODS

Forty-eight PE and 48 without PE patients (healthy pregnancies) matched for gestational age were included. Maternal age, parity, gestational age at delivery, obstetrical complications including intrauterine growth restriction (IUGR) and gestational diabetes mellitus (GDM), serum Apo A-1 and Apo B-100 levels, and the Apo B-100/Apo A-1 ratio were compared.

RESULTS

Preeclamptic patients had significantly lower Apo A-1 levels (167.07mg/dl±14.61mg/dl vs. 244.37mg/dl±20.84mg/dl, p<0.001), higher Apo B-100/Apo A-1 ratio (0.63±0.07 vs. 0.42±0.05, p<0.001), but similar Apo B-100 levels (104.84mg/dl±7.05mg/dl vs. 102.39mg/dl±8.08mg/dl, p=0.118). Mean Apo A-1 and Apo B-100 levels and the Apo B-100/Apo A-1 ratio were similar in patients with severe PE, HELLP syndrome, IUGR, and patients requiring antihypertensive therapy compared to PE patients who did not have these complications (p>0.05). Apo A-1 levels had the best accuracy followed by the Apo B-100/Apo A-1 ratio in patients with PE.

CONCLUSION

Apo A-1 and the Apo B-100/Apo A-1 ratio may be useful markers in patients with PE. Further studies are required to elucidate this issue.

Lipoprotein (a): impact by ethnicity and environmental and medical conditions

Levels of lipoprotein (a) [Lp(a)], a complex between an LDL-like lipid moiety containing one copy of apoB, and apo(a), a plasminogen-derived carbohydrate-rich hydrophilic protein, are primarily genetically regulated. Although stable intra-individually, Lp(a) levels have a skewed distribution inter-individually and are strongly impacted by a size polymorphism of the LPA gene, resulting in a variable number of kringle IV (KIV) units, a key motif of apo(a). The variation in KIV units is a strong predictor of plasma Lp(a) levels resulting in stable plasma levels across the lifespan. Studies have demonstrated pronounced differences across ethnicities with regard to Lp(a) levels and some of this difference, but not all of it, can be explained by genetic variations across ethnic groups. Increasing evidence suggests that age, sex, and hormonal impact may have a modest modulatory influence on Lp(a) levels. Among clinical conditions, Lp(a) levels are reported to be affected by kidney and liver diseases.

First Trimester Urine and Serum Metabolomics for Prediction of Preeclampsia and Gestational Hypertension: A Prospective Screening Study

Hypertensive disorders of pregnancy, including preeclampsia, are major contributors to maternal morbidity. The goal of this study was to evaluate the potential of metabolomics to predict preeclampsia and gestational hypertension from urine and serum samples in early pregnancy, and elucidate the metabolic changes related to the diseases. Metabolic profiles were obtained by nuclear magnetic resonance spectroscopy of serum and urine samples from 599 women at medium to high risk of preeclampsia (nulliparous or previous preeclampsia/gestational hypertension). Preeclampsia developed in 26 (4.3%) and gestational hypertension in 21 (3.5%) women. Multivariate analyses of the metabolic profiles were performed to establish prediction models for the hypertensive disorders individually and combined. Urinary metabolomic profiles predicted preeclampsia and gestational hypertension at 51.3% and 40% sensitivity, respectively, at 10% false positive rate, with hippurate as the most important metabolite for the prediction. Serum metabolomic profiles predicted preeclampsia and gestational hypertension at 15% and 33% sensitivity, respectively, with increased lipid levels and an atherogenic lipid profile as most important for the prediction. Combining maternal characteristics with the urinary hippurate/creatinine level improved the prediction rates of preeclampsia in a logistic regression model. The study indicates a potential future role of clinical importance for metabolomic analysis of urine in prediction of preeclampsia.

Maternal hyperlipidemia and the risk of preeclampsia: a meta-analysis

Published reports examining lipid levels during pregnancy and preeclampsia have been inconsistent. The objective of this meta-analysis was to test the association between preeclampsia and maternal total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), non-HDL-C, and triglyceride levels measured during pregnancy. We conducted a systematic search for studies published between the index date until July 2013 reporting maternal lipid levels in women with preeclampsia and normotensive pregnant women. Seventy-four studies met all eligibility criteria and were included in the meta-analysis. Weighted mean differences in lipid levels were calculated using a random-effects model. Statistical heterogeneity was investigated using the I(2) statistic. Meta-regression was used to identify sources of heterogeneity. Preeclampsia was associated with elevated total cholesterol, non-HDL-C, and triglyceride levels, regardless of gestational age at the time of blood sampling, and with lower levels of HDL-C in the third trimester. A marginal association was found with LDL-C levels. Statistical heterogeneity was detected in all analyses. Meta-regression analyses suggested that differences in body mass index (weight (kg)/height (m)(2)) across studies may be partially responsible for the heterogeneity in the triglyceride and LDL-C analyses. This systematic review and meta-analysis demonstrates that women who develop preeclampsia have elevated levels of total cholesterol, non-HDL-C, and triglycerides during all trimesters of pregnancy, as well as lower levels of HDL-C during the third trimester.

Cardiovascular risk, lipids and pregnancy: preeclampsia and the risk of later life cardiovascular disease

It has been widely thought that the effects of hypertension in pregnancy reversed after delivery and hypertension values returned to their pre-pregnancy level as it was seen as a disease of short duration in otherwise healthy young women. However, recent studies have demonstrated that the principal underlying abnormality, endothelial dysfunction, remains in women who had preeclampsia and that it is this damage that increases the risk of developing cardiovascular disease (CVD) in later life. The contributions of hypertension and dyslipidaemia before and during the pregnancy are also important and contribute to future risk. Serum lipids are complex and change dramatically in pregnancy. In general there is an increase in most plasma lipid components, notably triglycerides, total cholesterol and the major particles of HDL and LDL. Aberrations or exaggerations in this shift (i.e. decrease HDL and a greater increase in LDL) are associated with poor outcomes of pregnancy such as preeclampsia. Long term cardiovascular disease is influenced by preeclampsia and in part potentially by the lipid changes which escalate late in disease. Whether we can influence the risk of preeclampsia by controlling cardiovascular risk factors preceding or during preeclampsia, or cardiovascular disease after preeclampsia is yet to be determined. Ultimately, strategies to control lipid concentrations will only be viable when we understand the safety to the mother at the time of the pregnancy, and to the foetus both immediately and in the very long term. Strategies to control blood pressure are well established in the non-pregnant population, and previous preeclampsia and gestational hypertension should be considered in any cardiovascular risk profile. Whether control of blood pressure in the pregnancy per se is of any longer term benefit is also yet to be determined.

First-trimester metabolomic detection of late-onset preeclampsia

OBJECTIVE

We sought to identify first-trimester maternal serum biomarkers for the prediction of late-onset preeclampsia (PE) using metabolomic analysis.

STUDY DESIGN

In a case-control study, nuclear magnetic resonance-based metabolomic analysis was performed on first-trimester maternal serum between 11(+0)-13(+6) weeks of gestation. There were 30 cases of late-onset PE, i.e., requiring delivery ≥37 weeks, and 59 unaffected controls. The concentrations of 40 metabolites were compared between the 2 groups. We also compared 30 early-onset cases to the late-onset group.

RESULTS

A total of 14 metabolites were significantly elevated and 3 significantly reduced in first-trimester serum of late-onset PE patients. A complex model consisting of multiple metabolites and maternal demographic characteristics had a 76.6% sensitivity at 100% specificity for PE detection. A simplified model using fewer predictors yielded 60% sensitivity at 96.6% specificity. Strong separation of late- vs early-onset PE groups was achieved.

CONCLUSION

Significant differences in the first-trimester metabolites were noted in women who went on to developed late-onset PE and between early- and late-onset PE.

The current status of lipoprotein (a) in pregnancy: a literature review

BACKGROUND AND PURPOSE

Lipoprotein (Lp) (a) is a neglected element of the blood lipid profile. It is now recognized as a determinant of coronary heart disease progression and its role in atherosclerosis and its ability to induce thrombosis make it potentially important in the course of normal and complicated pregnancies. Pregnancy involves a major transformation of metabolism to sustain fetal growth. Multiple studies have been conducted on Lp(a) in pregnancy, and it is timely to synthesize and evaluate this evidence.

METHODS AND SUBJECTS

We reviewed the MEDLINE database for all articles published concerning "lipoprotein a" and "pregnancy" from May 2003 to May 2012. A previous comprehensive review assessed the literature up to May 2003.

RESULTS

We critically analyzed 14 studies detailing the effect of complications in pregnancy on Lp(a) profile, and subsequent pregnancy outcomes where available. Studies evaluating the normal metabolic response to pregnancy, pregnancies complicated by pre-eclampsia and intra-uterine growth restriction were reviewed.

CONCLUSIONS

A substantial mass of data has accumulated describing Lp(a) changes in pregnancy. The diversity of study design limits the ability to draw broad-ranging conclusions, but brings into focus the important questions remaining, which we discuss.