Increased placental phospholipid levels in pre-eclamptic pregnancies

Metabolomic prediction of severe maternal and newborn complications in preeclampsia

INTRODUCTION

Preeclampsia (PreE) remains a major source of maternal and newborn complications. Prenatal prediction of these complications could significantly improve pregnancy management.

OBJECTIVES

Using metabolomic analysis we investigated the prenatal prediction of maternal and newborn complications in early and late PreE and investigated the pathogenesis of such complications.

METHODS

Serum samples from 76 cases of PreE (36 early-onset and 40 late-onset), and 40 unaffected controls were collected. Direct Injection Liquid Chromatography-Mass Spectrometry combined with Nuclear Magnetic Resonance (NMR) spectroscopy was performed. Logistic regression analysis was used to generate models for prediction of adverse maternal and neonatal outcomes in patients with PreE. Metabolite set enrichment analysis (MSEA) was used to identify the most dysregulated metabolites and pathways in PreE.

RESULTS

Forty-three metabolites were significantly altered (p < 0.05) in PreE cases with maternal complications and 162 metabolites were altered in PreE cases with newborn adverse outcomes. The top metabolite prediction model achieved an area under the receiver operating characteristic curve (AUC) = 0.806 (0.660-0.952) for predicting adverse maternal outcomes in early-onset PreE, while the AUC for late-onset PreE was 0.843 (0.712-0.974). For the prediction of adverse newborn outcomes, regression models achieved an AUC = 0.828 (0.674-0.982) in early-onset PreE and 0.911 (0.828-0.994) in late-onset PreE. Profound alterations of lipid metabolism were associated with adverse outcomes.

CONCLUSION

Prenatal metabolomic markers achieved robust prediction, superior to conventional markers for the prediction of adverse maternal and newborn outcomes in patients with PreE. We report for the first-time the prediction and metabolomic basis of adverse maternal and newborn outcomes in patients with PreE.

Synthesis of phospholipids in human placenta

INTRODUCTION

Placental phospholipid synthesis is critical for the expansion of the placental exchange surface area and for production of signaling molecules. Despite their importance, it is not yet established which enzymes involved in the de novo synthesis and remodeling of placental phospholipids are expressed and active in the human placenta.

METHODS

We identified phospholipid synthesis enzymes by immunoblotting in placental homogenates and immunofluorescence in placenta tissue sections. Primary human trophoblast (PHT) cells from term healthy placentas (n = 10) were cultured and exposed to 13C labeled fatty acids (16:0, 18:1 and 18:2 n-6, 22:6 n-3) for 2 and 24 h. Three phospholipid classes; phosphatidic acid, phosphatidylcholine, and lysophosphatidylcholine containing 13C fatty acids were quantified by Liquid Chromatography with tandem mass spectrometry (LC/MS-MS).

RESULTS

Acyl transferase and phospholipase enzymes were detected in human placenta homogenate and primarily expressed in the syncytiotrophoblast. Three representative 13C fatty acids (16:0, 18:1 and 18:2 n-6) were incorporated rapidly into phosphatidic acid in trophoblasts, but 13C labeled docosahexaenoic acid (DHA; 22:6 n-3) incorporation was not detected. 13C DHA was incorporated into phosphatidylcholine. Lysophosphatidylcholine containing all four 13C labeled fatty acids were found in high abundance.

CONCLUSIONS

Phospholipid synthesis and remodeling enzymes are present in the syncytiotrophoblast. 13C labeled fatty acids were rapidly incorporated into cellular phospholipids. 13C DHA was incorporated into phospholipids through the remodeling pathway rather than by de novo synthesis. These understudied pathways are highly active and critical for structure and function of the placenta.

Lipid profile of circulating placental extracellular vesicles during pregnancy identifies foetal growth restriction risk

Small-for-gestational age (SGA) neonates exhibit increased perinatal morbidity and mortality, and a greater risk of developing chronic diseases in adulthood. Currently, no effective maternal blood-based screening methods for determining SGA risk are available. We used a high-resolution MS/MSALL shotgun lipidomic approach to explore the lipid profiles of small extracellular vesicles (sEV) released from the placenta into the circulation of pregnant individuals. Samples were acquired from 195 normal and 41 SGA pregnancies. Lipid profiles were determined serially across pregnancy. We identified specific lipid signatures of placental sEVs that define the trajectory of a normal pregnancy and their changes occurring in relation to maternal characteristics (parity and ethnicity) and birthweight centile. We constructed a multivariate model demonstrating that specific lipid features of circulating placental sEVs, particularly during early gestation, are highly predictive of SGA infants. Lipidomic-based biomarker development promises to improve the early detection of pregnancies at risk of developing SGA, an unmet clinical need in obstetrics.

Single-Cell RNA Sequencing and Microarray Analysis Reveal the Role of Lipid-Metabolism-Related Genes and Cellular Immune Infiltration in Pre-Eclampsia and Identify Novel Biomarkers for Pre-Eclampsia

Pre-eclampsia (PE) is a gestational hypertensive disorder that is characterized by hypertension and proteinuria, typically occurring after 20 weeks of gestation. Despite its global impact on pregnant women, the precise pathogenic mechanisms of PE remain unclear. Dysregulated lipid metabolism and immune cell infiltration contribute to PE development. Our study aimed to identify lipid-metabolism-related genes (LMRG-PEs) and investigate their association with immune infiltration. We utilized the "Seurat" R package for data quality control, cell clustering, and marker gene identification. The "SingleR" package enabled the matching of marker genes to specific cell types. Pseudotemporal ordering analysis was conducted using the "Monocle" package. Weighted correlation network analysis (WGCNA), gene set variation analysis (GSVA), and gene set enrichment analysis (GSEA) approaches were employed to explore lipid-metabolism-related genes, while potential targeted drugs were predicted using the drug-gene interaction database (DGIdb). Hub gene expression was validated through RT-qPCR. By analyzing single-cell RNA sequencing data, we identified and classified 20 cell clusters into 5 distinct types. Differential gene expression analysis revealed 186 DEGs. WGCNA identified 9 critical modules and 265 genes significantly associated with PE diagnosis, emphasizing the importance of the core genes PLA2G7 and PTGS2. RT-qPCR confirmed the significantly decreased expression of PLA2G7 and PTGS2 in PE patient tissues. These findings offer valuable insights into the molecular mechanisms of PE, particularly those involving lipid metabolism and immune infiltration. The identified hub genes have potential as therapeutic targets and biomarkers for future research and clinical applications.

Plasma lipids are dysregulated preceding diagnosis of preeclampsia or delivery of a growth restricted infant

BACKGROUND

Lipids serve as multifunctional metabolites that have important implications for the pregnant mother and developing fetus. Abnormalities in lipids have emerged as potential risk factors for pregnancy diseases, such as preeclampsia and fetal growth restriction. The aim of this study was to assess the potential of lipid metabolites for detection of late-onset preeclampsia and fetal growth restriction.

METHODS

We used a case-cohort of 144 maternal plasma samples at 36 weeks' gestation from patients before the diagnosis of late-onset preeclampsia (n = 22), delivery of a fetal growth restricted infant (n = 55, defined as <5th birthweight centile), gestation-matched controls (n = 72). We performed liquid chromatography-tandem mass spectrometry (LC-QQQ) -based targeted lipidomics to identify 421 lipids, and fitted logistic regression models for each lipid, correcting for maternal age, BMI, smoking, and gestational diabetes.

FINDINGS

Phosphatidylinositol 32:1 (AUC = 0.81) and cholesterol ester 17:1 (AUC = 0.71) best predicted the risk of developing preeclampsia or delivering a fetal growth restricted infant, respectively. Five times repeated five-fold cross validation demonstrated the lipids alone did not out-perform existing protein biomarkers, soluble tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) for the prediction of preeclampsia or fetal growth restriction. However, lipids combined with sFlt-1 and PlGF measurements improved disease prediction.

INTERPRETATION

This study successfully identified 421 lipids in maternal plasma collected at 36 weeks' gestation from participants who later developed preeclampsia or delivered a fetal growth restricted infant. Our results suggest the predictive capacity of lipid measurements for gestational disorders holds the potential to improve non-invasive assessment of maternal and fetal health.

FUNDING

This study was funded by a grant from National Health and Medical Research Council.

Membrane lipid changes in mouse blastocysts induced by ovarian stimulation, IVF and oocyte vitrification

RESEARCH QUESTION

Is the membrane lipid profile of mice blastocysts affected by ovarian stimulation, IVF and oocyte vitrification? Could supplementation of vitrification media with L-carnitine and fatty acids prevent membrane phospholipid changes in blastocysts from vitrified oocytes?

DESIGN

Experimental study comparing the lipid profile of murine blastocysts produced from natural mating, superovulated cycles or after IVF submitted or not to vitrification. For in-vitro experiments, 562 oocytes from superovulated females were randomly divided into four groups: fresh oocytes fertilized in vitro and vitrified groups: Irvine Scientific (IRV); Tvitri-4 (T4) or T4 supplemented with L-carnitine and fatty acids (T4-LC/FA). Fresh or vitrified-warmed oocytes were inseminated and cultured for 96 h or 120 h. The lipid profile of nine of the best quality blastocysts from each experimental group was assessed by multiple reaction monitoring profiling method. Significantly different lipids or transitions between groups were found using univariate statistics (P < 0.05; fold change = 1.5) and multivariate statistical methods.

RESULTS

A total of 125 lipids in blastocysts were profiled. Statistical analysis revealed several classes of phospholipids affected in the blastocysts by ovarian stimulation, IVF, oocyte vitrification, or all. L-carnitine and fatty acid supplements prevented, to a certain extent, changes in phospholipid and sphingolipid contents in the blastocysts.

CONCLUSION

Ovarian stimulation alone, or in association with IVF, promoted changes in phospholipid profile and abundance of blastocysts. A short exposure time to the lipid-based solutions during oocyte vitrification was sufficient to induce changes in the lipid profile that were sustained until the blastocyst stage.

Effect of birth rank, and placentome subtype on expression of genes involved in placental nutrient transport in sheep

Placental function is a key determinant of fetal growth and development that can be influenced by maternal and fetal environmental factors. The molecular mechanisms by which the placenta senses and responds to environmental cues are poorly understood. This exploratory study aimed to characterize the effect of birth rank (single vs. twin) and placentome morphologic subtype on expression of genes involved in nutrient transport, angiogenesis, immunity and stress response. Cotyledonary tissue was collected from type A, B and C placentomes from five single and six twin fetuses at 140 days of gestation. GLUT1 and GLUT3 were the most highly expressed genes consistent with the high demand for glucose to support fetal growth. Expression of BCKDHβ and IGF-2 was 1.3- and 1.5-fold higher, respectively, and PCYT1A was 3-fold lower in singles compared to twins (P < 0.05) while no other differences in gene expression were observed between birth ranks. Expression of EAAT2 and LAT2 was higher while PCYT1A was lower in A compared to B type cotyledons. Expression of GUCY1B1/3 and IGF-1 was higher while CD98 and LAT2 were lower in type B compared to C cotyledons (P < 0.05). Compared to type C cotyledons, expression of EAAT2, IGF-1, IGF-2, LAT1 was higher, while TEK was lower in type A cotyledons. The effects of birth rank on placental gene expression in this study indicated that placental nutrient transport and/or function differs between single and twin pregnancies in sheep. Differences in gene expression between the placentome subtypes suggests that changes in placentome morphology are associated with shifts in amino acid transport and metabolism, oxidative stress and angiogenesis and/or blood flow. This study highlights that placental gene expression differs in response to birth rank and placentome morphologic subtype which suggests that both maternal and fetal factors may influence placental function in sheep. These associations provide insights into gene pathways for more targeted future investigations as well as potential adaptations to improve placental efficiency to support fetal growth in twin pregnancies.

Adipokine chemerin overexpression in trophoblasts leads to dyslipidemia in pregnant mice: implications for preeclampsia

BACKGROUND

The adipokine chemerin regulates adipogenesis and the metabolic function of both adipocytes and liver. Chemerin is elevated in preeclamptic women, and overexpression of chemerin in placental trophoblasts induces preeclampsia-like symptoms in mice. Preeclampsia is known to be accompanied by dyslipidemia, albeit via unknown mechanisms. Here, we hypothesized that chemerin might be a contributor to dyslipidemia.

METHODS

Serum lipid fractions as well as lipid-related genes and proteins were determined in pregnant mice with chemerin overexpression in placental trophoblasts and chemerin-overexpressing human trophoblasts. In addition, a phospholipidomics analysis was performed in chemerin-overexpressing trophoblasts.

RESULTS

Overexpression of chemerin in trophoblasts increased the circulating and placental levels of cholesterol rather than triglycerides. It also increased the serum levels of lysophosphatidic acid, high-density lipoprotein cholesterol (HDL-C), and and low-density lipoprotein cholesterol (LDL-C), and induced placental lipid accumulation. Mechanistically, chemerin upregulated the levels of peroxisome proliferator-activated receptor g, fatty acid-binding protein 4, adiponectin, sterol regulatory element-binding protein 1 and 2, and the ratio of phosphorylated extracellular signal-regulated protein kinase (ERK)1/2 / total ERK1/2 in the placenta of mice and human trophoblasts. Furthermore, chemerin overexpression in human trophoblasts increased the production of lysophospholipids and phospholipids, particularly lysophosphatidylethanolamine.

CONCLUSIONS

Overexpression of placental chemerin production disrupts trophoblast lipid metabolism, thereby potentially contributing to dyslipidemia in preeclampsia.

Metabolomics analysis of placental tissue obtained from patients with fetal growth restriction

AIM

The aim of this study was to determine whether there was a difference in placental metabolite profiles between patients with fetal growth restriction (FGR) and healthy controls.

METHODS

The study included 10 patients with FGR diagnosis with 14 healthy controls with both matched maternal age and body mass index. ¹ H HR-MAS NMR spectroscopy data obtained from placental tissue samples of patients with FGR and healthy control group were analyzed with bioinformatics methods. The obtained results of metabolite levels were further validated with the internal standard (IS) quantification method.

RESULTS

Principal component analysis (PCA) and the partial least squares discriminant analysis (PLS-DA) score plots obtained with the multivariate statistical analysis of preprocessed spectral data shows a separation between the samples from patients with FGR and healthy controls. Bioinformatics analysis results suggest that the placental levels of lactate, glutamine, glycerophosphocholine, phosphocholine, taurine, and myoinositol are increased in patients with FGR compared to the healthy controls.

CONCLUSIONS

Placental metabolic dysfunctions are a common occurrence in FGR.

Physiological characterization of an arginine vasopressin rat model of preeclampsia

Rodent models have contributed greatly to our understanding of preeclampsia (PE) progression in humans, however to-date no model has been able to effectively replicate the clinical presentation of the disease. This study aimed to provide a thorough physiological characterization of the arginine vasopressin (AVP)-induced rat model of PE to determine its applicability in studying the pathophysiology of PE. Female Sprague Dawley rats (n = 24) were separated into four groups (n = 6 per group) viz., pregnant AVP, pregnant saline, non-pregnant AVP, and non-pregnant saline. All animals received a continuous dose of either AVP (150 ng/h) or saline via subcutaneous mini osmotic pumps for 18 days. Full physiological characterization of the model included measuring systolic and diastolic blood pressure, and collecting urine and blood samples for biochemical analysis. AVP infusion significantly increased blood pressure and urinary protein levels in the pregnant rats (p < 0.05). Biochemical markers measured, differed significantly in the AVP-treated vs the pregnant saline groups (p < 0.05). Placental and individual pup weight decreased significantly in the pregnant AVP vs pregnant saline group (p < 0.05). The physiological and hematological data confirm the usefulness of this rat model in the study of PE, since AVP-induced vasoconstriction increases peripheral resistance and successfully mimics the pathological changes associated with PE development in humans.Abbreviations: PE: preeclampsia; AVP: arginine vasopressin; ISSHP: International Society for the Study of Hypertension in Pregnancy; ACOG: American College of Obstetricians and Gynecologists; RUPP: reduced uterine perfusion pressure; sFlt-1: soluble fms-like tyrosine kinase; VEGF: vascular endothelial growth factor; PlGF: placental growth factor; AVP: arginine vasopressin; PAVP: pregnant AVP-treated; PS: pregnant saline; GD: gestational day; ALT: alanine transaminase; NAVP: non-pregnant AVP-treated; NS: non-pregnant saline; AST: aspartate aminotransferase; HDL: high-density lipoprotein; RBC: red blood cell; RAAS: renin-angiotensin aldosterone system; HELLP: hemolysis, elevated liver enzymes, low platelet.

Preeclampsia: From Cellular Wellness to Inappropriate Cell Death, and the Roles of Nutrition

Preeclampsia is one of the most common obstetrical complications worldwide. The pathomechanism of this disease begins with abnormal placentation in early pregnancy, which is associated with inappropriate decidualization, vasculogenesis, angiogenesis, and spiral artery remodeling, leading to endothelial dysfunction. In these processes, appropriate cellular deaths have been proposed to play a pivotal role, including apoptosis and autophagy. The proper functioning of these physiological cell deaths for placentation depends on the wellbeing of the trophoblasts, affected by the structural and functional integrity of each cellular component including the cell membrane, mitochondria, endoplasmic reticulum, genetics, and epigenetics. This cellular wellness, which includes optimal cellular integrity and function, is heavily influenced by nutritional adequacy. In contrast, nutritional deficiencies may result in the alteration of plasma membrane, mitochondrial dysfunction, endoplasmic reticulum stress, and changes in gene expression, DNA methylation, and miRNA expression, as well as weakened defense against environmental contaminants, hence inducing a series of inappropriate cellular deaths such as abnormal apoptosis and necrosis, and autophagy dysfunction and resulting in abnormal trophoblast invasion. Despite their inherent connection, the currently available studies examined the functions of each organelle, the cellular death mechanisms and the nutrition involved, both physiologically in the placenta and in preeclampsia, separately. Therefore, this review aims to comprehensively discuss the relationship between each organelle in maintaining the physiological cell death mechanisms and the nutrition involved, and the interconnection between the disruptions in the cellular organelles and inappropriate cell death mechanisms, resulting in poor trophoblast invasion and differentiation, as seen in preeclampsia.

Placental lipid metabolism in preeclampsia

OBJECTIVES

The current study examines the placental and maternal lipid profile and expression of genes involved in placental lipid metabolism in women with preeclampsia.

METHODS

The current study includes normotensive control women (n = 40) and women with preeclampsia (n = 39). Preeclampsia women were further classified into women delivering at term preeclampsia (T-PE; n = 15) and preterm preeclampsia (PT-PE; n = 24).

RESULTS

There were no significant differences in maternal lipid profile between the T-PE and normotensive control groups. Maternal plasma VLDL (P < 0.05) and ratios of total cholesterol : HDL (P < 0.05), atherogenic index [log (triglycerides/HDL)] (P < 0.01) and apolipoprotein B : apolipoprotein A (P < 0.05) were higher in the PT-PE group as compared with the normotensive control group. Placental total cholesterol and HDL levels were higher (P < 0.05) in the T-PE as compared with the normotensive control group. Higher placental triglycerides (P < 0.05) were observed in PT-PE group compared with T-PE group. Placental mRNA levels of peroxisome proliferator activated receptor α, carnitine palmitoyl transferase-1, cluster of differentiation 36 and lipoprotein lipases were lower (P < 0.05) in the PT-PE than normotensive control group. A negative association of mRNA levels of peroxisome proliferator activated receptor α (r = -0.246, P = 0.032; r = -0.308, P = 0.007, respectively), carnitine palmitoyl transferase-1 (r = -0.292, P = 0.011; r = -0.366, P = 0.001), lipoprotein lipases (r = -0.296, P = 0.010; r = -0.254, P = 0.028) with SBP and DBP was observed. There was a positive association of placental triglycerides (r = 0.244, P = 0.031) with DBP.

CONCLUSION

Women with preeclampsia exhibit higher lipid : lipoprotein ratios suggesting an atherogenic state particularly in women delivering preterm. Lower expression of genes involved in placental fatty acid oxidation and transport was also observed in preeclampsia.

Reduced neuropathy target esterase in pre-eclampsia suppresses tube formation of HUVECs via dysregulation of phospholipid metabolism

Recently, studies have shown that neuropathy target esterase (NTE) is essential to placental and normal blood vessel development. However, whether it is involved in abnormal placenta angiogenesis of pre-eclampsia remains unknown. Thus, our aim was to observe the expression of NTE in pre-eclamptic placentas and its effects and mechanism of NTE on the migration and the tube formation of human umbilical vein endothelial cells (HUVECs). Immunohistochemical staining showed that the NTE protein was intensely located in blood vessels of the normal pregnant placenta. However, western blot revealed that the expression level of NTE protein was significantly reduced in pre-eclamptic placenta. The results indicated that overexpression of NTE significantly promoted the migration and the tube formation of HUVECs compared with those of the control and scramble short hairpin RNA (shRNA) group. Conversely, NTE shRNA obviously inhibited the migration and the tube formation of HUVECs. Additionally, chromatography assay evidenced that NTE overexpression significantly reduced the level of phosphatidylcholine (PC) of HUVECs, but NTE shRNA obviously increased the level of PC of HUVECs. Furthermore, exogenous PC and lysophosphatidylcholine (LPC) significantly inhibited the tube formation of HUVECs in a dose-dependent manner. Collectively, our results suggest that reduced NTE in placenta may contribute to abnormal placenta angiogenesis of pre-eclampsia via the dysregulation of PC and LPC metabolism.

Placental Trophoblast-Inspired Lipid Bilayers for Cell-Free Investigation of Molecular Interactions

The placenta plays a key role in regulating the maternal-fetal transport but it is a difficult organ to study due to a lack of existing in vitro models. Lipid bilayers inspired by the placenta can provide a facile new in vitro tool with promise for screening molecular transport across this important organ. Here we developed lipid bilayers that mimic the composition of human placental trophoblast cells at different times during the course of pregnancy. Mass spectrometry identified five major lipid classes (phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and sphingomyelin) present at varying concentrations in trophoblasts representative of the first and third trimesters and full-term placenta. We successfully developed supported and suspended lipid bilayers mimicking these trophoblast lipid compositions and then demonstrated the utility of these synthetic placenta models for investigating molecular interactions. Specifically, we investigated the interactions with di(2-ethylhexyl) phthalate (DEHP), a common plasticizer and environmental toxicant, and amphotericin B, a common yet toxic, antifungal therapeutic. Overall, we observed that DEHP adsorbs and potentially embeds itself within all placental lipid bilayers, with varying levels of interaction. For both amphotericin B and a liposomal formulation of amphotericin B, AmBisome, we noted lower levels of permeation in transport studies with bilayers and trophoblast cells compared with DEHP, likely driven by differences in size. AmBisome interacted less with both the supported and suspended placental lipid bilayers in comparison to amphotericin B, suggesting that drug delivery carriers can vary the impact of a pharmaceutical agent on these lipid structures. We found that the apparent permeability observed in suspended bilayers was approximately an order of magnitude less than those observed for trophoblast monolayers, which is typical of lipid bilayers. Ultimately, these placenta mimetic lipid bilayers can serve as a platform for the rapid initial screening of molecular interactions with the maternal-fetal interface to better inform future testing.

Investigating the molecular structure of placenta and plasma in pre-eclampsia by infrared microspectroscopy

Pre-eclampsia (PE) is a serious hypertensive disorder with unclear etiology and lack of reliable diagnostic tests. In this study, IR microspectroscopy was applied to identify molecular changes associated with the pathogenesis of PE in placental tissues and plasma samples from pre-eclamptic women and normotensive matched controls. The obtained spectra were analyzed by multivariate analysis in the spectral ranges of 3050-2800 cm^-1 and 1855-1485 cm^-1 corresponding to lipid and protein-carbonyl components, respectively. In the lipid region, an increase in CH₂/CH₃ ratio was noticed and higher level of unsaturation index in placenta was evident. New lipid species emerged as a consequence of oxidative stress. The more intense peak at 1740 cm^-1 in PE reflected higher level of LDL and VLDL. In the protein region, a decrease in the α-helix structure associated with gain in β-sheet and β-turn structures was detected. Our results revealed significant conformational changes in the protein secondary structure in PE illustrated by peak shifts and intensity alterations, particularly in amide I component. Variations in lipid order, membrane integrity, fatty acid saturation and plasma lipid profile were also detected in PE. The ROC curve generated from plasma samples yielded AUC values of 98.4% and 99.9% for lipid and protein-carbonyl regions, respectively. The current study shed light on the promising role of IR microspectroscopy as a new analytical tool that can aid in providing better diagnosis and understanding of the pathophysiology of PE.

Artificial intelligence and the analysis of multi-platform metabolomics data for the detection of intrauterine growth restriction

OBJECTIVE

To interrogate the pathogenesis of intrauterine growth restriction (IUGR) and apply Artificial Intelligence (AI) techniques to multi-platform i.e. nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) based metabolomic analysis for the prediction of IUGR.

MATERIALS AND METHODS

MS and NMR based metabolomic analysis were performed on cord blood serum from 40 IUGR (birth weight < 10th percentile) cases and 40 controls. Three variable selection algorithms namely: Correlation-based feature selection (CFS), Partial least squares regression (PLS) and Learning Vector Quantization (LVQ) were tested for their diagnostic performance. For each selected set of metabolites and the panel consists of metabolites common in three selection algorithms so-called overlapping set (OL), support vector machine (SVM) models were developed for which parameter selection was performed busing 10-fold cross validations. Area under the receiver operating characteristics curve (AUC), sensitivity and specificity values were calculated for IUGR diagnosis. Metabolite set enrichment analysis (MSEA) was performed to identify which metabolic pathways were perturbed as a direct result of IUGR in cord blood serum.

RESULTS

All selected metabolites and their overlapping set achieved statistically significant accuracies in the range of 0.78-0.82 for their optimized SVM models. The model utilizing all metabolites in the dataset had an AUC = 0.91 with a sensitivity of 0.83 and specificity equal to 0.80. CFS and OL (Creatinine, C2, C4, lysoPC.a.C16.1, lysoPC.a.C20.3, lysoPC.a.C28.1, PC.aa.C24.0) showed the highest performance with sensitivity (0.87) and specificity (0.87), respectively. MSEA revealed significantly altered metabolic pathways in IUGR cases. Dysregulated pathways include: beta oxidation of very long fatty acids, oxidation of branched chain fatty acids, phospholipid biosynthesis, lysine degradation, urea cycle and fatty acid metabolism.

CONCLUSION

A systematically selected panel of metabolites was shown to accurately detect IUGR in newborn cord blood serum. Significant disturbance of hepatic function and energy generating pathways were found in IUGR cases.

Involvement of follistatin-like 3 in preeclampsia

INTRODUCTION

Preeclampsia is a main cause of maternal and perinatal mortality and morbidity. The expression of follistatin-like 3 (FSTL3) is enhanced in maternal serum and placenta of preeclamptic women. However, whether FSTL3 is involved in the pathophysiologic of preeclampsia has not been clarified yet.

METHOD

Trophoblast cell lines Swan71 and JAR cells were cultured and siRNA was used to silence FSTL3. The expression of FSTL3 was determined by Western blotting. The matrigel-coated transwell and wound healing assays were used to assess invasion and migration, cell proliferation and apoptosis were detected by CCK-8 and flow cytometric analysis, respectively. Oil red O staining was used to detect the lipid storage in trophoblast.

RESULTS

Hypoxia culture significantly enhanced the expression of FSTL3 by trophoblast. Down-regulation of FSTL3 significantly suppressed the proliferation, migration, invasion and lipid storage but increased apoptosis of trophoblast.

DISCUSSION

Aberrant expression of FSTL3 in preeclampsia led to the dysfunction of trophoblast, indicating its involvement in the pathogenesis of preeclampsia.

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.

Identification of placental nutrient transporters associated with intrauterine growth restriction and pre-eclampsia

Background

Gestational disorders such as intrauterine growth restriction (IUGR) and pre-eclampsia (PE) are main causes of poor perinatal outcomes worldwide. Both diseases are related with impaired materno-fetal nutrient transfer, but the crucial transport mechanisms underlying IUGR and PE are not fully elucidated. In this study, we aimed to identify membrane transporters highly associated with transplacental nutrient deficiencies in IUGR/PE.

Results

In silico analyses on the identification of differentially expressed nutrient transporters were conducted using seven eligible microarray datasets (from Gene Expression Omnibus), encompassing control and IUGR/PE placental samples. Thereby 46 out of 434 genes were identified as potentially interesting targets. They are involved in the fetal provision with amino acids, carbohydrates, lipids, vitamins and microelements. Targets of interest were clustered into a substrate-specific interaction network by using Search Tool for the Retrieval of Interacting Genes. The subsequent wet-lab validation was performed using quantitative RT-PCR on placentas from clinically well-characterized IUGR/PE patients (IUGR, n = 8; PE, n = 5; PE+IUGR, n = 10) and controls (term, n = 13; preterm, n = 7), followed by 2D-hierarchical heatmap generation. Statistical evaluation using Kruskal-Wallis tests was then applied to detect significantly different expression patterns, while scatter plot analysis indicated which transporters were predominantly influenced by IUGR or PE, or equally affected by both diseases. Identified by both methods, three overlapping targets, SLC7A7, SLC38A5 (amino acid transporters), and ABCA1 (cholesterol transporter), were further investigated at the protein level by western blotting. Protein analyses in total placental tissue lysates and membrane fractions isolated from disease and control placentas indicated an altered functional activity of those three nutrient transporters in IUGR/PE.

Conclusions

Combining bioinformatic analysis, molecular biological experiments and mathematical diagramming, this study has demonstrated systematic alterations of nutrient transporter expressions in IUGR/PE. Among 46 initially targeted transporters, three significantly regulated genes were further investigated based on the severity and the disease specificity for IUGR and PE. Confirmed by mRNA and protein expression, the amino acid transporters SLC7A7 and SLC38A5 showed marked differences between controls and IUGR/PE and were regulated by both diseases. In contrast, ABCA1 may play an exclusive role in the development of PE.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-4518-z) contains supplementary material, which is available to authorized users.

Transfer and Metabolism of Cortisol by the Isolated Perfused Human Placenta

CONTEXT

Fetal overexposure to glucocorticoids in utero is associated with fetal growth restriction and is postulated to be a key mechanism linking suboptimal fetal growth with cardiovascular disease in later life.

OBJECTIVE

To develop a model to predict maternal-fetal glucocorticoid transfer. We hypothesized placental 11-β-hydroxysteroid dehydrogenase-type 2 (11β-HSD2) would be the major rate-limiting step in maternal cortisol transfer to the fetus.

DESIGN

We used a deuterated cortisol tracer in the ex vivo placental perfusion model, in combination with computational modeling, to investigate the role of interconversion of cortisol and its inactive metabolite cortisone on transfer of cortisol from mother to fetus.

PARTICIPANTS

Term placentas were collected from five women with uncomplicated pregnancies, at elective caesarean delivery.

INTERVENTION

Maternal artery of the isolated perfused placenta was perfused with D4-cortisol.

MAIN OUTCOME MEASURES

D4-cortisol, D3-cortisone, and D3-cortisol were measured in maternal and fetal venous outflows.

RESULTS

D4-cortisol, D3-cortisone, and D3-cortisol were detected and increased in maternal and fetal veins as the concentration of D4-cortisol perfusion increased. D3-cortisone synthesis was inhibited when 11-β-hydroxysteroid dehydrogenase (11β-HSD) activity was inhibited. At the highest inlet concentration, only 3.0% of the maternal cortisol was transferred to the fetal circulation, whereas 26.5% was metabolized and 70.5% exited via the maternal vein. Inhibiting 11β-HSD activity increased the transfer to the fetus to 7.3% of the maternal input, whereas 92.7% exited via the maternal vein.

CONCLUSIONS

Our findings challenge the concept that maternal cortisol diffuses freely across the placenta and confirm that 11β-HSD2 acts as a major "barrier" to cortisol transfer to the fetus.

Effect of Maternal Obesity on Placental Lipid Metabolism

Obese women, on average, give birth to babies with high fat mass. Placental lipid metabolism alters fetal lipid delivery, potentially moderating neonatal adiposity, yet how it is affected by maternal obesity is poorly understood. We hypothesized that fatty acid (FA) accumulation (esterification) is higher and FA β-oxidation (FAO) is lower in placentas from obese, compared with lean women. We assessed acylcarnitine profiles (lipid oxidation intermediates) in mother-baby-placenta triads, in addition to lipid content, and messenger RNA (mRNA)/protein expression of key regulators of FA metabolism pathways in placentas of lean and obese women with normal glucose tolerance recruited at scheduled term Cesarean delivery. In isolated trophoblasts, we measured [3H]-palmitate metabolism. Placentas of obese women had 17.5% (95% confidence interval: 6.1, 28.7%) more lipid than placentas of lean women, and higher mRNA and protein expression of FA esterification regulators (e.g., peroxisome proliferator-activated receptor γ, acetyl-CoA carboxylase, steroyl-CoA desaturase 1, and diacylglycerol O-acyltransferase-1). [3H]-palmitate esterification rates were increased in trophoblasts from obese compared with lean women. Placentas of obese women had fewer mitochondria and a lower concentration of acylcarnitines, suggesting a decrease in mitochondrial FAO capacity. Conversely, peroxisomal FAO was greater in placentas of obese women. Altogether, these changes in placental lipid metabolism may serve to limit the amount of maternal lipid transferred to the fetus, restraining excess fetal adiposity in this population of glucose-tolerant women.

A Lipidomic Analysis of Placenta in Preeclampsia: Evidence for Lipid Storage

In preeclampsia, maternal insulin resistance leads to defective expansion of adipocytes, enhanced adipocyte lipolysis, up-regulation of very low density lipoprotein synthesis, maternal hypertriglyceridaemia and the potential for ectopic fat storage. Our aim was to quantitate and compare the total amount and type of lipid in placenta from pregnancies complicated with preeclampsia and healthy pregnancies. Quantitative lipid analysis of lipid extracts from full thickness placental biopsies was carried out by shotgun lipidomics. Placental lipid profiles from pregnancies complicated by preeclampsia (n = 23) were compared to healthy pregnancies (n = 68), and placenta from intrauterine growth restriction pregnancies (n = 10) were used to control for gross differences in placental pathology. Placentae from pregnancies complicated with preeclampsia had higher neutral lipid content than healthy placentae (40% higher triacyglycerol (P = 0.001) and 33% higher cholesteryl ester (P = 0.004)) that was specific to preeclampsia and independent of maternal gestation.

Hypoxic treatment of human dual placental perfusion induces a preeclampsia-like inflammatory response

Preeclampsia is a human pregnancy-specific disorder characterized by a placental pro-inflammatory response in combination with an imbalance of angiogenic factors and clinical symptoms, including hypertension and proteinuria. Insufficient uteroplacental oxygenation in preeclampsia due to impaired trophoblast invasion during placentation is believed to be responsible for many of the molecular events leading to the clinical manifestations of this disease. We investigated the use of hypoxic treatment of the dual placental perfusion system as a model for preeclampsia. A modified perfusion technique allowed us to achieve a mean soluble oxygen tension within the intervillous space (IVS) of 5-7% for normoxia and <3% for hypoxia (as a model for preeclampsia). We assayed for the levels of different inflammatory cytokines, oxidative stress markers, as well as other factors, such as endothelin (ET)-1 that are known to be implicated as part of the inflammatory response in preeclampsia. Our results show a significant increase under hypoxia in the levels of different inflammatory cytokines, including IL-6 (P=0.002), IL-8 (P<0.0001), TNF-α (P=0.032) and IFN-γ (P=0.009) at 360 min in maternal venous samples (n=6). There was also a significant increase in ET-1 levels under hypoxia both on the maternal side at 30 min (P=0.003) and fetal side at 360 min (P=0.036) (n=6). Other markers of oxidative stress, including malondialdehyde and 8-iso-protaglandin F2α (P=0.009) also show increased levels. Overall, these findings indicate that exposure of ex vivo dually perfused placental tissue to hypoxia provides a useful model for mimicking the inflammatory response characteristic of preeclampsia. This would therefore provide a powerful tool for studying and further delineating the molecular mechanisms involved in the underlying pathophysiology of preeclampsia.

Placental ABCA1 and ABCG1 expression in gestational disease: Pre-eclampsia affects ABCA1 levels in syncytiotrophoblasts

INTRODUCTION

Transplacental feto-maternal lipid exchange through the ATP-binding cassette transporters ABCA1 and ABCG1 is important for normal fetal development. However, only scarce and conflicting data exist on the involvement of these transporters in gestational disease.

METHODS

Placenta samples (n = 72) derived from common gestational diseases, including pre-eclampsia (PE), HELLP, intrauterine growth restriction (IUGR), intrahepatic cholestasis of pregnancy and gestational diabetes, were assessed for their ABCA1 and ABCG1 expression levels and compared to age-matched control placentas with qRT-PCR and immunohistochemistry. ABCA1 expression was additionally investigated with immunoblot in placental membrane vesicles. Furthermore, placental cholesterol and phospholipid contents were assessed.

RESULTS

ABCA1 mRNA levels differed significantly between preterm and term control placentas (p = 0.0013). They were down-regulated in isolated PE and PE with IUGR (p = 0.0006 and p = 0.0012, respectively), but unchanged in isolated IUGR, isolated HELLP and other gestational diseases compared to gestational age-matched controls. Correspondingly, in PE, ABCA1 protein expression was significantly reduced in the apical membrane of the villous syncytiotrophoblast (p = 0.011) and in villous fetal endothelial cells (p = 0.036). Furthermore, in PE there was a significant increase in the placental content of total and individual classes of phospholipids which were partially correlated with diminished ABCA1 expression. Conversely, ABCG1 mRNA and protein levels were stable in the investigated conditions.

CONCLUSIONS

In gestational disease, there is a specific down-regulation of placental ABCA1 expression at sites of feto-maternal lipid exchange in PE. At a functional level, the increase in placental lipid concentrations provides indirect evidence of an impaired transport capacity of ABCA1 in this disease.